Acta Botanica Cassubica. Monographiae

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1 Acta Botanica Cassubica 3 Monographiae Katedra Taksonomii Roœlin i Ochrony Przyrody Uniwersytetu Gdañskiego Renata Afranowicz VEGETATION OF WATERCOURSES AND THEIR MARGINS UNDER INTENSE ANTHROPOPRESSURE IN THE U AWY WIŒLANE REGION (NORTHERN POLAND) ROŒLINNOŒÆ CIEKÓW I ICH OBRZE Y W WARUNKACH SILNEJ ANTROPOPRESJI NA U AWACH WIŒLANYCH (PÓ NOCNA POLSKA) Gdañsk 2009

2 Redakcja RYSZARD MARKOWSKI redaktor naczelny JOANNA BLOCH-OR OWSKA sekretarz redakcji DARIUSZ L. SZLACHETKO KATARZYNA Ó KOŒ TOMASZ S. OLSZEWSKI Komitet redakcyjny WIES AW FA TYNOWICZ Uniwersytet Wroc³awski JACEK HERBICH Uniwersytet Gdañski KAROL LATOWSKI Uniwersytet im. A. Mickiewicza w Poznaniu ANDRZEJ NIENARTOWICZ Uniwersytet Miko³aja Kopernika w Toruniu Acta Botanica Cassubica, Monographiae jest czasopismem recenzowanym Druk sfinansowany przez: Rektora Uniwersytetu Gdañskiego ds. Nauki, Dziekana Wydzia³u Biologii Uniwersytetu Gdañskiego Projekt ok³adki TOMASZ S. OLSZEWSKI Fotografia na ok³adce Nupharo-Nymphaeetum albae (fot. R. AFRANOWICZ) Fragment haftu kaszubskiego na ok³adce wykorzystano za zgod¹ wydawcy Oficyny Czec. Copyright by Katedra Taksonomii Roœlin i Ochrony Przyrody Uniwersytetu Gdañskiego, Gdañsk 2009 PL ISSN Sk³ad i ³amanie: URSZULA JÊDRYCZKA Druk: Zak³ad Poligrafii Fundacji Rozwoju Uniwersytetu Gdañskiego Sopot, ul. Armii Krajowej 119/121 tel./fax (58) , tel , poligraf@gnu.univ.gda.pl

3 Vegetation of watercourses and their margins under intense anthropopressure in the u³awy Wiœlane region (northern Poland) Roœlinnoœæ cieków i ich obrze y w warunkach silnej antropopresji na u³awach Wiœlanych (pó³nocna Polska) RENATA AFRANOWICZ Katedra Taksonomii Roœlin i Ochrony Przyrody, Uniwersytet Gdañski, Al. Legionów 9, Gdañsk, biora@univ.gda.pl ABSTRACT: The main aim of the study was to characterize types of vegetation connected with watercourses of different origin and morphometry and to evaluate the role of artificial watercourses as potential refuges for natural vegetation in the anthropogenic landscape of the Wis³a river delta. The research was conducted on 241 sites within the u³awy Wiœlane region during The study concerned the vegetation of contemporary watercourses and their margins. In each site phytosociological data (relevés) were collected; altogether 326 relevés were made. The studied objects were characterized by the width and depth of watercourse as well as by the type of its bottom. Also the watercourse condition was described, including the maintaining techniques and land use type in the adjacent area. Habitat diversity was estimated according to Ellenberg s bioindicators of reaction (R), nitrogen (N) and salinity (S). Ordination of vegetation samples was made with Detrended Correspondence Analysis (DCA) method, in CANOCO 4.5 program. The results indicated that vegetation of artificial watercourses (canals and drainage ditches) shows considerable similarity to vegetation of natural watercourses. The half of all plant communities observed in the studied area is connected with both natural and artificial watercourses and doesn t express clear preference to their size. Moreover, patches of those plant associations are the most frequently observed. Watercourse type and morphometry have in turn an effect on distribution of community types and size of the area covered by them. The intense human impact, especially maintenance of canals and drainage ditches, causes disturbance of vegetation and habitats. Newly uncovered places are often being overgrown by expansive plant species. KEY WORDS: vegetation, natural and artificial watercourses, anthropopressure, the u³awy Wiœlane region ARANOWICZ R Vegetation of watercourses and their margins under intense anthropopressure in the u³awy Wiœlane region (northern Poland). Roœlinnoœæ cieków i ich obrze y w warunkach silnej antropopresji na u³awach Wiœlanych (pó³nocna Polska). Acta Bot. Cassub., Monogr. 3: 1-94.

4 Contents Introduction Study area Material and methods Objects of the detailed research and their location Description of the vegetation and habitats of the studied objects Statistical analyses Results Vegetation of natural and artificial watercourses Syntaxonomic list of plant communities Characteristics of plant communities Correlations between vegetation and chosen features of watercourse and human impact Commonness of plant communities Phytocoenotical diversity versus watercourse size and origin Spatial diversity of plant communities in particular types of watercourses Discussion Conclusions Acknowledgements References Streszczenie Annex

5 Vegetation of watercourses and their margins... # Introduction u³awy Wiœlane (the Wis³a river delta) is an area, which distinguishes on the scale of Poland by its history, cultural heritage, landscape and natural environment. The uniqueness of the region is a result of specific origin, which affected particular habitat conditions. The development of the Wis³a river delta, started 7 thousands years ago, came under dynamic geological, geomorphological, hydrological and anthropogenic processes. The intensity and duration of those processes had a vast influence on development and changes of plant cover of u³awy Wiœlane. Human impact, which had been increasing gradually since the end of the 13 JD century, played especially important role in last few centuries. The most significant elements of that pressure were: deforestation, establishment of dense network of artificial watercourses drainage canals and ditches as well as building flood walls. Along with human settlement, more and more areas of very fertile alluvial muds and organic soils were drained and used for agriculture. Contemporary plant cover of the u³awy Wiœlane region is a reflection of natural processes, connected with several centuries long accumulation activity of the Wis³a river as well as with anthropogenic processes. Researches on the plant cover of that area started fairly tardily, in the second quarter of 20 JD century (see Abromeit et al ; Kalkreuth 1926, 1928, 1932). The later papers concerned among others the plant cover of watercourses and their margins, although most of them was concentrated on Druzno Lake (Schulz 1941; Lenczewski 1955, 1957; Kluszczyñska, Szmeja 1979; Strawiñski et al. 1985; Klim 1988; Buliñski 1998; Markowski et al. 2002), or referred to selected fragments of the Wis³a river delta (Dziedzic 1991a, b; Œroda 1991a, b, c; 2000a, b, c; Œroda et al. 2002). Those mentioned above papers, although explain many problems associated with plant cover of aquatic and waterlogged habitats, answer only some of the research questions and rather show the gaps in the knowledge. One of the aspects that remains unsolved is to recognize relations between the contemporary plant cover and the origin, character and changes of the watercourses, in connection with other components of abiotic environment. The area of the Wis³a river delta is especially suitable for such research due to the dense hydrological network and strong direct and indirect human interference into its shape. The main aim of the study was to characterize types of vegetation connected with watercourses of different origin and morphometry and to evaluate the role of artificial watercourses as potential refuges for natural vegetation in the anthropogenic landscape of the u³awy Wiœlane region.

6 6 Renata Afranowicz 1. Study area The research was carried out in the entire u³awy Wiœlane region (Fig. 1), which covers the plain area of about 2460 km (Kondracki 2002). In the physicalgeographical regionalization by Kondracki (2002) the area is defined as the u³awy Wiœlane mesoregion, while in geobotanical division it is called the u³awy Wis³y province (Szafer 1977). Fig. 1. Location of the study area ( u³awy Wiœlane 1997) The Wis³a river delta is distinguished from adjacent regions: Wzniesienia Elbl¹skie laying on the north-east, Pojezierze I³awskie and Dolina Kwidzyñska

7 Vegetation of watercourses and their margins... 7 on the south and Pojezierze Kaszubskie and Starogardzkie on the west, by many specific features. Among the most significant ones there are: a plain surface, the biggest in Poland participation of depression areas (Starkel 2001), observed influence of continental and maritime climate (Kwiecieñ 1982) and human activity that modifies natural alluvial processes of rivers. The most characteristic feature of the studied area is a very dense hydrographic network, which consists of natural and artificial watercourses (Fig. 2). That network covers 70% of the total area of the u³awy region (Matusik, Szczêsny 1976). The surface waters consist of large rivers (Wis³a, Nogat, Szkarpawa, Martwa Wis³a and others), smaller natural watercourses (e.g. Œwiêta, Tina, Balewka), Druzno Lake with the area ca km (Drwal 1991) and many artificial watercourses. The last ones take the main part in the hydrographic network of u³awy Wiœlane. Total length of the artificial watercourses is about 20 thousands km, among which 3000 km belongs to canals and other km to subsidiary ditches (Kondracki 2002). Fig. 2. Hydrographic network of the Wis³a river delta (according to Czarnecka et al. 1987)

8 8 Renata Afranowicz 2. Material and methods 2.1. Objects of the detailed research and their location The field work was carried out in vegetative seasons of years The study concerned the vegetation of contemporary watercourses altogether with their margins. Each site was located in ATPOL square grid (Zaj¹c 1978), detailed to lower range squares of 5 km sides, which were signed with a-d letters (see Markowski, Buliñski 2004). The studied watercourses were divided due to the origin into natural, i.e. developed without human interference, and artificial ones, i.e. of direct anthropogenic origin. Inside each kind of watercourses, additional categories connected with the width of water surface were established: natural small (sn) up to 10 m wide large (ln) wider than 10 m artificial ditches (d) up to 2 m wide, used for drainage and melioration; their seasonally changeable water level can be regulated small canals (sc) 2 to 10 m wide large canals (lc) wider than 10 m, with hydrological character similar to large, regulated rivers The field research concerning natural and artificial watercourses and their margins was carried out in chosen sites spread over the whole area of u³awy Wiœlane. Location of the study sites with referring to the ATPOL grid is given on Fig. 3. During the study, a 50 m long fragment of watercourse was treated as one locality. In case of large rivers and canals (above 10 m wide), localities were distanced from each other for at least 500 m and were placed on each side of the watercourse separately. Altogether 241 sites were investigated, among which there were 94 in natural watercourses and 147 in artificial ones (65 in canals and 82 in drainage ditches). The detailed list of all studied localities is given in Table Description of the vegetation and habitats of the studied objects In each studied site phytosociological data (relevés) were collected according to the Braun-Blanquet method (Paw³owski 1977). Syntaxonomic classification of plant communities was taken after Matuszkiewicz (2005), with the exception of Wolffietum arrhizae association, which was identified according to Miyawaki and Tüxen (1960). Altogether 326 relevés were made in water and marginal zones of the watercourses. They were arranged in 26 phytosociological tables, among which aquatic communities were compiled in 12 tables (126 relevés) and Reed swamps

9 Vegetation of watercourses and their margins... 9 Fig. 3. Location of the study sites in the watercourses of the Wis³a river delta, with reference to the ATPOL grid Table 1. The detailed list of the study sites. Abbreviations as in the text above Site no. Watercourse type Square no. in modified ATPOL grid Locality description 1. d DA95c 1 km E of Cieplice I 2. d DA95c 1.25 km N of Cieplice I 3. lc DA95c 0.75 km NE of Cieplice II 4. d DA95c 1.25 km NE of Nowotki 5. sn DB22c 1.80 km S of Mi³oradz 6. ln DB22d 1 km SW of Pogorza³a Wieœ 7. ln DB32a 0.5km NE of Piek³o 8. ln DB32a 0.5km NE of Piek³o 9. ln DB32a 0.5km NE of Piek³o 10. d DB22d 1.25km S of Raczki Elbl¹skie 11. sc DB15a 2 km N of Raczki Elbl¹skie 12. d DB15a 0.5 km N of Raczki Elbl¹skie 13. d DB15a 0.7 km N of Raczki Elbl¹skie 14. ln DB15b 0.75 km SE of Raczki Elbl¹skie 15. d DB15b 0.8 km SE of Raczki Elbl¹skie

10 10 Renata Afranowicz Site no. Watercourse type Square no. in modified ATPOL grid Locality description 16. d DB15b 1 km SE of Raczki Elbl¹skie 17. sc DB15b 0.75 km S of Raczki Elbl¹skie 18. sc DB15d 1.8 km S of urawiec 19. sc DB15d 0.5 km N of Wêgle 20. sc DB15d 1.25 km S of ukowo 21. d DB15d 0.12 km SW of Jurandowo 22. d DB15d 0.15 km SW of Jurandowo 23. sc DB23b 0.5km SW of Kamienica 24. d DB13d 1.25km N of Szawa³d 25. d DB13d 2 km SE of Lasowice Ma³e 26. sn DB13d 2 km S of Lasowice Ma³e 27. sc DB13c 0.25km E of Tragamin 28. sn DB05c 2 km N of Kazimierzowo 29. sc DB05c 1.6 km N of Kazimierzowo 30. d DB05c 2.1 km NW of Kazimierzowo 31. ln DB05c 1 km W of Józefowo 32. ln DB05c 0.75 km W of PGR Nowakowo I 33. d DB05c 0.75 km W of Janowo 34. sc DB04d 0.4 km S of Józefowo 35. sc DB04d 1.2 km SW of Józefowo 36. sc DB05c 0.5 km W of Kazimierzowo 37. sc DB05c 2.8 km NE of Kazimierzowo 38. d DB05c 0.12 km E of Nowakowo II 39. sc DB05c 0.37 km SW of Kazimierzowo 40. sc DB14b 2 km S of Wiktorowo 41. d DB14b 0.8 km N of Jeg³ownik 42. lc DA92c 0.37 km NE of PGR B³otnik I 43. sc DA93c 3 km SE of u³awki 44. sc DB02a 0.25km N of D³ugie Pole I 45. ln DB32a 0.5 km NE of Piek³o 46. d DA92b 1.25km NE of u³awki 47. ln DA92b 1.1 km NE of u³awki 48. ln DA92b 0.75km E of Przemys³aw 49. d DA92b 1.5km NW of Przemys³aw 50. sn DA93a 0.25 km S of Izbiska 51. sn DA93a 0.25 km N of Stegienka 52. sn DA93b 1 km SE of Stegna 53. sc DA93d 1.25 km S of Rybina 54. d DA93d 1 km W of PGR Nowotna 55. ln DA93d 1.2 km W of PGR Nowotna 56. sc DA93c 0.12 km S of PGR Szkarpawa 57. d DA93c 1.6 km SW of PGR Szkarpawa 58. sc DA91d Woc³awy

11 Vegetation of watercourses and their margins Site no. Watercourse type Square no. in modified ATPOL grid Locality description 59. sn DA91c 1.25 km SW of Woc³awy 60. sn DB01a 0.5km S of Grabina-Zameczek 61. ln DB01d 0.5km N of Suchy Dab 62. d DA91c 2.5km E of Pruszcz Gdañski 63. d DA91c 2.2 km E of Pruszcz Gdañski 64. lc DB02a Leszkowy-Wybudowania 65. d DB02b 1.18 km S of Kiezmark 66. ln DA94c PGR Che³mek 67. ln DA94c 0.75km S of P³onino 68. d DA94d 1.3 km SE of Dublewo 69. d DA94d 1.5km NE of Dublewo 70. ln DA94b 2.3 km SE of Kobyla Kêpa 71. ln DA94b 2 km NE of Kobyla Kêpa 72. ln DA94a 0.5km SE of Sztutowo 73. sn DA94b 2.1 km NE of Kobyla Kêpa 74. ln DB04d 0.75km SW of Kêpki 75. ln DB04b 1 km SW of Stobna 76. sn DB04b 0.8 km SW of Kêpiny Ma³e 77. ln DB05a 0.8 km NW of Kêpa Rybacka 78. ln DA94d 1.5km S of Nowotki 79. d DA94d 1 km N of PGR Wê owiec 80. ln DA94d 1.2 km N of PGR Wê owiec 81. lc DA94d 1.6 km N of Marzêcino 82. lc DA94d 2.75km N of Marzêcino 83. ln DA94c Os³onka 84. d DA94c 0.75km SW of PGR Che³mek 85. ln DA94c 1.25 km SW of PGR Che³mek 86. d DA94c 1 km NW of Stobiec 87. d DA94c 1 km NW of Stobiec 88. d DA94c 1.2 km NW of Stobiec 89. sn DB04a Orliniec 90. sn DB04a Orliniec 91. d DB04a Orliniec 92. d DB04a 1.5km NE of Solnica 93. sc DB04a 1 km E of PGR Ró ewo 94. sc DA94c 2 km NW of Marzêcino 95. d DA94c 1.75 km NW of Marzêcino 96. lc DB04a 1.5km N of Orliniec 97. d DB03d 1 km NW of Myszewko 98. sc DB13b 1 km NW of Lasowice Ma³e 99. sc DB13d 0.75km SE of Lasowice Ma³e 100. sc DB13b 0.8 km S of PGR Myszewko 101. sc DB13b 0.75km S of PGR Myszewko

12 12 Renata Afranowicz Site no. Watercourse type Square no. in modified ATPOL grid Locality description 102. sn DB14d 1.5km N of Gronowo Elbl¹skie 103. d DB15c 1.25 km N of Gronowo Elbl¹skie 104. sc DB15c 1.6 km NE of Gronowo Elbl¹skie 105. d DB15c 0.5 km NE of Jesionno 106. sc DB15c 1.4 km NE of Gronowo Elbl¹skie 107. sc DB15a 1.8 km S of Karczowiska Górne 108. d DB15a 1.3 km S of Karczowiska Górne 109. sn DB15a 1 km N of Karczowiska Górne 110. ln DB15c 1.5 km NW of Jezioro 111. sc DB25b 0.6 km SE of Krzewsko 112. ln DB25b Balewo 113. ln DB25b Dzierzgonka 114. d DB25b 0.15 km SE of Dzierzgonka 115. d DB25b 0.75 km SW of Nowe Dolno 116. ln DB25d 0.5 km NE of Brudzêdy 117. lc DB25d 0.5 km NW of Brudzêdy 118. sc DB25b 0.5 km SW of Rachowo 119. d DB25b 0.6 km NE of Rachowo 120. d DB25b Markusy 121. d DB15c 1.3 km SW of Jezioro 122. d DB15c 1.75 km SW of Jezioro 123. sc DB15c 1.8 km SW of Jezioro 124. ln DB15c 0.3 km S of Zdroje 125. sc DB15c 1.5 km N of Zwierzeñskie Pola 126. sc DB25a 0.25 km SE of Ró any 127. d DB25a 0.2 km S of Ró any 128. sc DB25a 0.25 km N of Zwierzno 129. sn DB24b 0.1 km SE of Szaleniec 130. sn DB24b 0.3 km W of Szaleniec 131. d DB14d Oleœno 132. d DB14d 2.5km SW of Oleœno 133. sn DB24b 1.25km SE of Z³otowo 134. sc DB24a 0.6 km SE of Z³otowo 135. sn DB24a 1.5 km SW of Krzy anowo 136. ln DB13d Janówko 137. sc DB05c 0.5 km S of PGR Adamowo 138. sn DB15a 0.1 km S of Helenowo 139. sn DB03c PGR Lubiszynek I 140. ln DB03d 1.25km NW of Marynowy 141. sn DB03d 1 km NW of Marynowy 142. sc DB02b 1.6 km NW of PGR Stawiec 143. d DB12c 0.5km S of Lichnówki 144. d DB12c 0.75km S of Lichnówki

13 Vegetation of watercourses and their margins Site no. Watercourse type Square no. in modified ATPOL grid Locality description 145. sc DB12c 1.5 km NE of Szymankowo 146. sn DB12d 1 km NE of Starynia 147. sc DB02c 0.5km NE of Pordenowo 148. d DA95c 1.25 km W of PGR Batorowo 149. sc DA95c 1 km SE of Nowotki 150. d DB13c Tragamin 151. d DA81c 0.5 km N of Przejazdowo 152. sn DA81c 0.25 km N of Przejazdowo 153. d DA91b 1.5 km SE of PGR Wiœlinka 154. lc DA92a 2.75 km SE of PGR Wiœlinka 155. lc DA92c 1.25 km N of Cedry Wielkie 156. d DA91d 0.75 km NW of Cedry Wielkie 157. sc DA91d 1.5 km SE of Mi³ocin 158. sn DA91d 1.25 km SE of Mi³ocin 159. ln DB11b 0.5 km SE of Tczewskie ¹ki 160. ln DB11b 0.6 km NE of Tczewskie ¹ki 161. sc DB11b 1.25km NE of Tczewskie ¹ki 162. ln DB01d Krzywe Ko³o 163. ln DB01d 0.4 km N of Krzywe Ko³o 164. sc DB14c 0.8 km N of PGR Kaczynos I 165. d DB14c 0.7 km NE of PGR Kaczynos I 166. sc DB14c 1.5km N of Kaczynos 167. d DB14c 1 km SE of Kaczynos 168. sn DB14c 1.3 km NW of Fiszewo 169. sn DB14c 1.4 km NW of Z¹browo 170. sc DB14d 2 km NE of Z¹browo 171. sc DB14d 2.75km NE of Z¹browo 172. sn DB05c 1.25 km W of Helenowo 173. sn DB05c 1.5 km W of Helenowo 174. ln DB03b Nowy Dwór Gdañski 175. sc DB03a Stare Babki 176. sc DB03a 1.75km SE of Stare Babki 177. ln DB03a 0.6 km SW of Cyganki 178. sc DA81d Sobieszewo 179. ln DA81d 0.6 km SE of Sobieszewo 180. ln DA81d 1.2 km SE of Sobieszewo 181. ln DA81d 0.3 km W of Sobieszewko 182. ln DA92a 0.3 km SE of Sobieszewko 183. ln DA92a Sobieszewska Pastwa 184. ln DA92a 1 km SE of Sobieszewska Pastwa 185. ln DA92a 1.6 km SE of Sobieszewska Pastwa 186. ln DA92a 0.5km SW of Komary 187. ln DA92a 0.5km W of Przegalina

14 14 Renata Afranowicz Site no. Watercourse type Square no. in modified ATPOL grid Locality description 188. lc DA92a Trzcinowo 189. ln DA92a 0.5km NE of Trzcinowo 190. ln DA92a 1.5km NE of Trzcinowo 191. d DA91b 0.75km NE of PGR Koszwa³y 192. ln DB14d 2 km NW of Oleœno 193. d DB14d 1.6 km NW of Oleœno 194. d DB14d 1.5km NW of Oleœno 195. ln DA93d 0.75 km SE of Tujsk 196. sn DB03d 1.1 km N of Myszewko 197. sn DB03d 1 km NW of Myszewko 198. ln DB14c 1 km NE of Letniki 199. sn DA94a PGR Grochowo III 200. ln DB15a 0.6 km S of Helenowo 201. ln DB15a 0.6 km N of Szopy 202. d DB15a 0.5 km N of Szopy 203. ln DB15a 1.5 km N of Szopy 204. d DB14c 1.25km SW of Fiszewo 205. sn DB14c 1.25 km S of Letniki 206. ln DB14c 1.5km S of Letniki 207. d DB15a 1.25 km S of Jeg³ownik 208. d DB15a 1.25 km S of Jeg³ownik 209. d DB15a 1.4 km S of Jeg³ownik 210. d DB15a 1.6 km S of Jeg³ownik 211. d DB15a 1.8 km S of Jeg³ownik 212. d DB15a 1.9 km S of Jeg³ownik 213. d DB15a 1.5 km S of Jeg³ownik 214. d DB15a 0.75 km S of Jeg³ownik 215. d DB15a 0.6 km S of Jeg³ownik 216. sn DB22c 2 km S of Mi³oradz 217. ln DA94d 1.5km W of Nowotki 218. ln DA94d 1.75km N of PGR Wê owiec 219. sn DA94d 0.7 km SW of PGR Wê owiec 220. sn DA94d 0.5km SW of PGR Wê owiec 221. ln DA94d 1.5km NW of Nowotki 222. lc DB05c 0.5 km SE of PGR Nowakowo II 223. lc DB05a 0.75 km N of PGR Nowakowo II 224. lc DB05a 2.5 km SE of Kêpa Rybacka 225. d DB05a 2.3 km SE of Kêpa Rybacka 226. d DB05a 2 km SE of Kêpa Rybacka 227. d DB05a 0.8 km S of Ujœcie 228. sn DA95c 1 km NE of PGR Batorowo 229. d DB05a 0.5 km NE of Kêpki 230. d DB04b 0.5km E of Stobna

15 Vegetation of watercourses and their margins Site no. Watercourse type Square no. in modified ATPOL grid Locality description 231. d DB04b 0.25km E of Stobna 232. d DB04b 0.5km W of Stobna 233. lc DB05a 1 km NE of Kêpa Rybacka 234. lc DB05a 1 km NW of Nowe Batorowo 235. d DA95c 1 km NE of Kêpiny Wielkie 236. d DB22b 0.5km E of Stara Koœcielnica 237. lc DB02a 0.25km N of D³ugie Pole I 238. d DB22a Bystrze 239. d DB12b 1 km E of Parszewo 240. d DB13a 1 km W of Œwierki 241. d DB02b 1 km S of PGR Lubieszewo in 14 (200 relevés). During the research, plant communities of both permanently and seasonally flooded areas, as well as those located in the nearest neighbourhood of the watercourse beds, were investigated. The studied objects were characterized by the width of water surface and the depth of watercourse (established with measuring tape and telescopic level staff) as well as by the type of watercourse bottom. Also the watercourse condition was described, including the maintaining techniques and land use type in the adjacent area. Information of the condition, functioning and maintaining of the drainage network in the u³awy Wiœlane region were achieved from local units of the Voivodship Managements for Melioration and Water Infrastructure in Elbl¹g, Pruszcz Gdañski and Nowy Dwór Gdañski (Dane Zarz¹du Melioracji ). Also some hydrological studies of the region were useful in investigation of changes of water conditions (Majewski 1969; Fac-Beneda 1999, 2002; Drwal 2000). Habitat diversity was estimated according to Ellenberg s bioindicator method (Ellenberg 1992). Indicator values of reaction (R), nitrogen (N) and salinity (S) for species of particular study sites were taken into account. Nomenclature of vascular plants follows Mirek et al. (2002), with the exception of Polygonum amphibium f. natans and P. amphibium f. terrestre (Rutkowski 2004). Names of liverworts are accepted after Szweykowski (2006). English names of plant species and communities are according to Ellenberg (1988). Identifications of Potamogeton species were verified by Dr. Joanna Zalewska-Ga³osz from Jagiellonian University in Kraków Statistical analyses Ordination of vegetation samples represented by relevés was made according to Detrended Correspondence Analysis (DCA) method, in CANOCO 4.5 program (ter Braak, Šmilauer 2002). Such a method was used due to unimodal

16 16 Renata Afranowicz character of the data and to the gradient length which was over 4 standard deviations (Lepš, Šmilauer 2004). The DCA method allowed indirect analyzing of environmental gradients which are revealed on the basis of floristic composition of the samples. Environmental factors were characterized by particular variables, concerning categories of watercourses. Indicators of reaction, nutrient and salinity were treated as additional variables (Ellenberg 1992). Before application of Detrended Correspondence Analysis, cover values of plant species were transformed from Braun-Blanquet scale into 7-point ordinal scale (Lepš, Šmilauer 2004) using the following values: r 1,+ 2,1 3,2 4,3 5,4 6,5 7 For chosen Ellenberg s indicators the weighted averages, including quantitative occurrence of species, were estimated for each relevé, according to following formula ( omnicki 2000): X M x / ME E ME where: w E = weight (quantitative occurrence) of the species, = value of Ellenberg s indicator for given species. x E Interpretation of diagrams, that are the graphical result of DCA analysis, was made according to following rules: samples (representing particular relevés) are displayed as points, variables such as categories of watercourses are also displayed as points, values of Ellenberg s indicators are presented as arrows, neighbouring samples show higher similarity in the received environmental gradient, expressed by chosen variables, distanced samples differ significantly in floristic composition, arrows indicate the direction of changes of variable s intensity, and the arrow length shows importance of that variable, vertical projection of points (representing relevés) onto an axis of the variable vector allows ordering them in the gradient of that factor. Relevés were preliminarily grouped according to hierarchical classification, with the use of methods of complete linkage and Euclidean distance as similarity measures. Calculations were made in Statistica 6.0 packet. The detailed results of the analysis were presented in work by Afranowicz (2004).

17 Vegetation of watercourses and their margins Results 3.1. Vegetation of natural and artificial watercourses Syntaxonomic list of plant communities Class: Lemnetea minoris R.Tx Order: Lemnetalia minoris R.Tx Alliance: Lemnion gibbae R.Tx. et A.Schwabe 1974 in R.Tx Association: Spirodeletum polyrhizae (Kelhofer 1915) W.Koch 1954 em. R.Tx. et A.Schwabe 1974 in R.Tx Association: Lemnetum gibbae Miy. et J.Tx Association: Wolffietum arrhizae Miy. et J.Tx Alliance: Riccio fluitantis-lemnion trisulcae R.Tx. et A.Schwabe 1974 in R.Tx Association: Ricciocarpetum natantis Segal 1963 em. R.Tx Association: Lemnetum trisulcae (Kelhofer 1915) Knapp et Stoffers 1962 Alliance: Lemno minoris-salvinion natantis Slavniæ 1956 em. R.Tx. et A.Schwabe 1981 Association: Lemno minoris-salvinietum natantis (Slavniæ 1956) Korneck 1959 Class: Potametea R.Tx. et Prsg Order: Potametalia Koch 1926 Alliance: Potamion Koch 1926 em. Oberd Association: Elodeetum canadensis (Pign. 1953) Pass Association: Ceratophylletum demersi Hild Association: Myriophylletum spicati Soe 1927 Association: Ranunculetum circinati (Bennema et West. 1943) Segal 1965 Association: Potametum pectinati Carstensen 1955 Association: Potametum lucentis Hueck 1931 Association: Potametum friesi Tomasz Alliance: Nymphaeion Oberd Association: Potametum natantis Soó 1923 Association: Polygonetum natantis Soó 1927 Association: Nymphoidetum peltatae (All. 1922) Bellot 1951 Association: Myriophylletum verticillati Soó 1927 Association: Hydrocharitetum morsus-ranae Langendonck 1935 Association: Nupharo-Nymphaeetum albae Tomasz Alliance: Hottonion Segal 1964 Association: Hottonietum palustris R.Tx Class: Phragmitetea R.Tx. et Prsg 1942 Order: Phragmitetalia Koch 1926 Alliance: Phragmition Koch 1926

18 18 Renata Afranowicz Association: Sparganietum erecti Roll 1938 Association: Typhetum angustifoliae (Allorge 1922) Soó 1927 Association: Typhetum latifoliae Soó 1927 Association: Phragmitetum australis (Gams 1927) Schmale 1939 Association: Acoretum calami Kobendza 1948 Association: Glycerietum maximae Hueck 1931 Association: Oenantho-Rorippetum Lohm Association: Scirpetum maritimi (Br.-Bl. 1931) R.Tx Alliance: Magnocaricion Koch 1926 Association: Caricetum ripariae Soó 1928 Association: Caricetum acutiformis Sauer 1937 Association: Caricetum gracilis (Graebn. et Hueck 1931) R.Tx Association: Thelypteridi-Phragmitetum Kuiper 1957 Association: Iridetum pseudacori Eggler 1933 Association: Phalaridetum arundinaceae (Koch 1926 n.n.) Lib Characteristics of plant communities Association: Spirodeletum polyrhizae (Kelhofer 1915) W.Koch 1954 em. R.Tx. et A.Schwabe 1974 in R.Tx (Table 2, relevés 1-13) The Giant duckweed cover contains the most primitive phytocoenoses of tiny free-floating water plants. It is one of the most common aquatic communities, which grew in both natural and artificial watercourses in the whole area of u³awy Wiœlane. In small rivers and canals as well as in drainage ditches, phytocoenoses of Spirodeletum polyrhizae covered the water surface at the major length of the watercourse, due to a weak flow of the water. However, in large rivers (e.g. Nogat, Mot³awa, Tina Dolna, and Dzierzgoñ) those communities appeared only in the bankside area or in parts of river bend, where they were shifted by the midstream. In such circumstances they also formed a surface layer within Reed swamp communities. Patches of that association consisted of small amount of taxa from 3 to 8 (Table 2). Spirodela polyrhiza was a dominant, which formed dense films covering even the whole surface of the water. The accompanying species were Lemna minor and less frequently L. gibba. Additional species were: Hydrocharis morsusranae, Salvinia natans and Nuphar lutea, especially in natural watercourses. The layer of submerged plants was usually poorly developed and only exceptionally it covered 40% of the area (Table 2). In such situations Lemna trisulca played a significant role and it was accompanied by Cerathophyllum demersum, and in large rivers also by Potamogeton lucens. Sporadic occurrence of the mentioned submerged macrophytes was connected with strong dimness caused by surface plants.

19 Vegetation of watercourses and their margins Table 2. Spirodeletum polyrhizae (Kelhofer 1915) W.Koch 1954 em. R.Tx. et A.Schwabe 1974 in R.Tx Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type sc ln ln sn ln sn ln sn d lc d lc lc Cover of above water herb layer c (%) - < surface water herb layer c (%) submerged herb layer c! (%) 40 <520 <1 - <1 - <1 < <1 Water depth (m) Relevé area (m ) Number of species Ch. Spirodeletum polyrhizae Spirodela polyrhiza c Ch. Lemnion gibbae, Lemnetalia minoris, Lemnetea minoris Lemna minor c Lemna trisulca c! Salvinia natans c Lemna gibba Accompanying species: Ch. Nymphaeion*, Potamion, Potametalia, Potametea *Hydrocharis morsus-ranae c *Nuphar lutea Ceratophyllum demersum c! Potamogeton lucens Sporadic species: c : *Nymphaea alba 5(+), c!: Utricularia vulgaris 1 (1), Elodea canadensis 6 (+) Other species: Sporadic species: c: Catabrosa aquatica 2 (+) Association: Lemnetum gibbae Miy. et J.Tx (Table 3, relevés 1-6) The Gibbous Duckweed cover, similarly as the previously described community, is represented by dense phytocoenoses of pleustonic Duckweeds, floating freely on the surface of water. It is a rare association, although it has relatively frequent localities in the u³awy Elbl¹skie and u³awy Gdañskie sub-regions. Phytocoenoses of Lemnetum gibbae occur mostly in small, rather shallow, very slowly flowing rivers and canals.

20 20 Renata Afranowicz Table 3. Lemnetum gibbae Miy. et J.Tx (relevés 1 6), Wolffietum arrhizae Miy. et J.Tx (relevés 7 10) i Ricciocarpetum natantis Segal 1963 em. R.Tx (relevés 11, 12) Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type ln sn sn sn sn d ln sc sn d sn sc Cover of above water herb layer c (%) <1 - < surface water herb layer c (%) submerged herb layer c! (%) - <1 - <1 < Water depth (m) Relevé area (m ) Number of species Ch. Lemnetum gibbae Lemna gibba c Ch. Wolffietum arrhizae Wolffia arrhiza c Ch. Ricciocarpetum natantis Ricciocarpus natans c Ch. Lemnion gibbae, Riccio fluitantis-lemnion trisulcae, Lemnetalia minoris, Lemnetea minoris Lemna minor c Spirodela polyrhiza Lemna trisulca c! Sporadic species: c :Salvinia natans 8 (+) Accompanying species: Ch. Nymphaeion*, Potamion, Potametalia, Potametea *Nuphar lutea c *Hydrocharis morsus-ranae Sporadic species: c :*Potamogeton natans 1(2),*Nymphaea alba 1(1), Polygonum amphibium f. natans 1 (+), c!: Ceratophyllum demersum 2 (+), Elodea canadensis 5(+) Other species: Glyceria maxima c Typha latifolia Iris pseudacorus Sporadic species: Sagittaria sagittifolia 3 (2), Rorippa amphibia 11 (+), Solanum dulcanmara 11 (+), Lycopus europaeus 11 (+), Sium latifolium 12 (+), Phragmites australis 12 (+)

21 Vegetation of watercourses and their margins Patches of that association, similarly to Spirodeletum polyrhizae, formed a dense mat on the surface of water, with cover often reaching % of the area. It was build by the subdominant species Lemna gibba, sometimes accompanied by L. minor and occasionally by Hydrocharis morsus-ranae and Spirodela polyrhiza (see Table 3). The submerged layer, which was significantly less developed than the surface one, consisted of: Ceratophyllum demersum, Elodea canadensis and Lemna trisulca. Association: Wolffietum arrhizae Miy. et J.Tx (Table 3, relevés 7-10) The Dwarf Duckweed community is represented by usually dense, two-layer phytocoenoses of pleustonic plants. It is one of the very rare plant associations of the studied area (Afranowicz 2002). It appeared in small, mainly artificial watercourses. It remained also in regularly conserved canals close to Gronowo Elbl¹skie and Kaczynos localities. Patches of that association were characterized by poor floristic composition: from 3 to 6 species (see Table 3). Wolffia arhiza (Photo 1) was the main component, while Lemna gibba, L. minor and Spirodela polyrhiza occurred often as accompanying species with relatively high cover. In most phytocoenoses the cover of surface water layer reached maximum values. Other taxa appeared sporadically, except from Lemna trisulca, which was the only representative of submerged macrophytes (see Table 3). Association: Ricciocarpetum natantis Segal 1963 em. R.Tx (Table 3, relevés 11, 12) The association of Purple-fringed Riccia is community of small pleustonic plants that appeared rarely in the u³awy Wiœlane region. It was noted in two localities in small watercourses: natural and the artificial one (canal), which were distinguished by muddy bottom and water depth not exceeding 0.7 m. Observed phytocoenoses occurred in sheltered and shaded places. Ricciocarpus natans were a dominant species, building up relatively dense patches on the water surface. The Lemna minor and L. trisulca were regular components of community. Also some Reed swamp taxa, especially Typha latifolia, Glyceria maxima and Iris pseudacorus occurred (see Table 3). Association: Lemnetum trisulcae (Kelhofer 1915) Knapp et Stoffers 1962 (Table 4, relevés 1-11) The Ivy-leaved Duckweed community includes two-layer phytocoenoses of pleustophytes, with well developed submerged layer. They were widespread in the studied area and appeared more often in small canals and drainage ditches than in natural watercourses. The community was mainly connected with still or slowly flowing water, with the depth not exceeding 1.2 m. The phytocoenoses were built by aggregations of Lemna trisulca. The species formed a submerged layer, which thickness reached up to 0.1 m in places with stagnating and shallow water. In such circumstances Ivy-leaved Duckweed covered 100% of the area. In the surface water layer occurred: Lemna gibba, L. minor, Hydrocharis

22 22 Renata Afranowicz morsus-ranae, Spirodela polyrhiza and Nuphar lutea especially in natural watercourses (see Table 4). Species abundance in particular patches was variable, thus the cover of the upper layer was widely differentiated from below 5% up to 95%. Table 4. Lemnetum trisulcae (Kelhofer 1915) Knapp et Stoffers 1962 Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type sc d sc d sc sc ln d d sc sn Cover of above water herb layer c (%) 10 < <1 - surface water herb layer c (%) <1 <1 <1 <1 <5 submerged herb layer c! (%) Water depth (m) Relevé area (m ) Number of species Ch. Lemnetum trisulcae Lemna trisulca c! Ch. Riccio fluitantis-lemnion trisulcae, Lemnetalia minoris, Lemnetea minoris Lemna minor c Spirodela polyrhiza Lemna gibba Sporadic species: Salvinia natans 1 (+) Accompanying species: Ch. Nymphaeion*, Hottonion**, Potametalia, Potametea *Hydrocharis morsus-ranae c *Nuphar lutea Ceratophyllum demersum c! **Hottonia palustris c Sporadic species: c :*Nymphaea alba 7 (+), c!: Potamogeton filiformis 1 (+) Ch. Phragmitetea Sporadic species: c: Alisma plantago-aquatica 1(+), Sagittaria sagittifolia 1 (+), Acorus calamus 2 (1), Phragmites australis 2 (+), Glyceria maxima 10 (+) Association: Lemno minoris-salvinietum natantis (Slavniæ 1956) Korneck 1959 (Table 5, relevés 1-10) The association of Floating Watermoss and Lesser Duckweed showed increasing propagation in the u³awy Wiœlane region. Patches of the community were noted in all types of watercourses, although most frequently they occurred in the natural ones.

23 Vegetation of watercourses and their margins Table 5. Lemno minoris-salvinietum natantis (Slavniæ 1956) Korneck 1959 Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type sc d ln sc ln ln lc ln ln d Cover of above water herb layer c (%) < surface water herb layer c (%) submerged herb layer c! (%) <1 < <1 - <1 - Water depth (m) Relevé area (m ) Number of species Ch. Lemno minoris-salvinietum natantis Salvinia natans c Ch. Lemnion minoris-salvinion natantis, Lemnetalia minoris, Lemnetea minoris Lemna minor c Spirodela polyrhiza Lemna trisulca c! Sporadic species: c : Wolffia arrhiza 4 (+), Lemna gibba 5(+) Accompanying species: Ch. Nymphaeion*, Hottonion**, Potametalia, Potametea Ceratophyllum demersum c! *Hydrocharis morsus-ranae c *Nuphar lutea *Nymphaea alba Sporadic species: c!: Elodea canadensis 1 (+), c : *Stratiotes aloides 4(1), Potamogeton natans 8 (2), **Callitriche cophocarpa 10 (+) Other species: Sporadic species: c: Sagittaria sagittifolia 6 (+) Phytocoenoses were built by plants with floating leaves, among which aquatic fern Salvinia natans (Photo 2) was a dominant species and it reached 3 H@ to 5 JD degree of the cover scale. Among other diagnostic species of the class Lemnetea minoris the most abundant were: Lemna minor, L. trisulca and Spirodela polyrhiza (see Table 5). The other important component of the community was Hydrocharis morsus-ranae. Also some submerged macrophytes, most frequently Ceratophyllum demersum, played role in forming two-layer structure of the patches.

24 24 Renata Afranowicz In recent years Salvinia natans has spread widely over the area of u³awy Wiœlane. Multi-ares patches of the association were observed e.g. in rivers: Nogat, Fiszewka, Linawa, Tuga, Tina and Szkarpawa, in canals: Wiœlano-Zalewowy and Panieñski as well as in smaller natural and artificial watercourses. Particularly in 2002 those phytocoenoses were widespread and covered large areas, limiting appearance of the other communities of aquatic macrophytes. Association: Elodeetum canadensis (Pign. 1953) Pass (Table 6, relevés 1 15) This is a submerged plant community, built up mainly by Canadian Waterweed. Phytocoenoses of Elodeetum canadensis were widespread over Wis³a river delta. They mostly developed in smaller canals, as well as in small natural watercourses and were not observed in large rivers of u³awy Wiœlane. The characteristic species of the association Elodea canadensis often formed single-species aggregations. In phytocoenoses, beside Canadian Waterweed, there was always at least one Duckweed species. Taxa of the class Potametea: Hydrocharis morsus-ranae or Ceratophyllum demersum appeared less often. Watercourses, in which Elodea canadensis existed, become overgrown very quickly. One year after maintaining, the species overrun the watercourse again, forming well developed patches of this association (Table 6, relevés 1, 10, 13 and 15). Elodea canadensis is a North American species (Cook, Urmi-König 1985), which was found in the surroundings of Gdañsk for the first time in 1867 (Klatt 1867, after Abromeit et al ). At present that hydrophyte is widespread over u³awy Wiœlane. Association: Ceratophylletum demersi Hild (Table 7, relevés 1-13) This is association of submerged macrophytes, with dominance of Common Hornwort. It was one of common plant communities of the u³awy Wiœlane region. It appeared in both natural and artificial watercourses with slowly flowing or stagnating water. Phytocoenoses of the association had structure of single- or two-layer patches, characterized by poor floristic composition not exceeding 6 species. Ceratophyllum demersum was a dominant species among submerged plants and Lemna trisulca played significant role among accompanying species. Occasionally also species of the genus Potamogeton appeared. Moreover, the lower was the cover of surface water plants the higher was cover of the submerged layer. Among that last group Lemna minor, L. gibba, Spirodela polyrhiza and Hydrocharis morsus-ranae were the most frequent. Patches of Ceratophylletum demersi, due to its considerable phytomass production, took significant part in shallowing of the watercourses. They were also characterized by high ability of regeneration and expansion, as they were well developed just in the next vegetative season after watercourse cleaning (Table 7, relevés 1, 3).

25 Vegetation of watercourses and their margins Table 6. Elodeetum canadensis (Pign. 1953) Pass Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type sc sc sc sn sn sn sn sc d sc sc d sc sc sc Cover of above water herb layer c (%) - < < surface water herb layer c (%) < <5<5 5 < <1 20 <5 submerged herb layer c! (%) < Water depth (m) Relevé area (m ) Number of species Ch. Elodeetum canadensis Elodea canadensis c! Callitriche cophocarpa c Ch. Potamion, Nymphaeion*, Potametalia, Potametea Ceratophyllum demersum c! *Hydrocharis morsus-ranae c *Nuphar lutea Potamogeton friesii c! Polygonum amphibium f. natans c Sporadic species: c!: Potamogeton pusillus 3 (+), Myriophyllum spicatum 4 (2), Myriophyllum verticillatum 6 (+), Potamogeton trichoides 8 (+), Potamogeton natans 9 (+) Accompanying species: Ch. Lemnetea minoris Lemna minor c Lemna trisulca c! Spirodela polyrhiza c Lemna gibba Sporadic species: c :Wolffia arrhiza 14 (+) Ch. Phragmitetea Sagittaria sagittifolia c Sporadic species: Sparganium emersum 2 (+), Sium latifolium 3 (+), Sparganium erectum 3 (+), Alisma plantago-aquatica 7 (+)

26 26 Renata Afranowicz Table 7. Ceratophylletum demersi Hild Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type d sc d d sn d sn sc sn sn lc d d Cover of above water herb layer c (%) < surface water herb layer c (%) <1 5<5< <1 <1 - submerged herb layer c! (%) Water depth (m) Relevé area (m ) Number of species Ch. Ceratophylletum demersi Ceratophyllum demersum Ch. Potamion, Nymphaeion*, Potametalia, Potametea *Hydrocharis morsus-ranae c Potamogeton pectinatus c! Myriophyllum spicatum *Nuphar lutea c Potamogeton natans Sporadic species: c!: Elodea canadensis 4 (1), Potamogeton filiformis 7 (2), Potamogeton trichoides 8 (+), Myriophyllum verticillatum 10 (2) Accompanying species: Ch. Lemnetea minoris Lemna minor c Lemna trisulca c! Spirodela polyrhiza c Lemna gibba Salvinia natans Wolffia arrhiza Other species: Sporadic species: c: Sagittaria sagittifolia 6 (+) Association: Myriophylletum spicati Soe 1927 (Table 8, relevés 1, 2) That association was represented by facies phytocoenoses of Eurasian Watermilfoil. In u³awy Wiœlane it occurred rarely and in dispersed localities. It grew

27 Vegetation of watercourses and their margins in natural and artificial watercourses, in slowly flowing waters, of the depth not exceeding 1 m. In the phytocoenoses Myriophyllum spicatum was a dominant species and it formed dense, small patches. The quantitative and qualitative participation of the other species was minimal (see Table 8). Sporadically emerged plants and submerged macrophytes appeared and among them only Lemna minor was more abundant. Table 8. Myriophylletum spicati Soe 1927 (relevés 1, 2) and Ranunculetum circinati (Bennema et West. 1943) Segal 1965 (relevés 3 6) Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type ln sc ln ln ln ln Cover of above water herb layer c (%) surface water herb layer c (%) 510 <10 5<5<1 submerged herb layer c! (%) Water depth (m) Relevé area (m ) Number of species Ch. Myriophylletum spicati Myriophyllum spicatum c! Ch. Ranunculetum circinati Batrachium circinatum c! Ch. Nymphaeion*, Hottonion**, Potamion, Potametalia, Potametea *Nuphar lutea c Ceratophyllum demersum c! *Hydrocharis morsus-ranae c *Nymphaea alba Sporadic species: c!: Elodea canadensis 2 (+) Accompanying species: Ch. Lemnetea minoris Lemna trisulca c! Lemna minor c Salvinia natans Sporadic species: c : Spirodela polyrhiza 1 (+)

28 28 Renata Afranowicz Association: Ranunculetum circinati (Bennema et West. 1943) Segal 1965 (Table 8, relevés 3-6) The association was represented by dense phytocoenoses of submerged plants, mostly Fan-leaved Water-crowfoot. In the u³awy Wiœlane region well developed patches of that association were noted only in rivers, such as: Nogat, Szkarpawa and Martwa Wis³a. Batrachium circinatum was a dominant species. It occurred massively, reaching the highest cover degree (see Table 8). The other taxa played minor role. Only Lemna trisulca and Nuphar lutea appeared more often. The cover of surface water plants was below 10%. Association: Potametum pectinati Carstensen 1955 (Table 9, relevés 1, 2) The Fennel-leaved Pondweed community was represented by floristically poor phytocoenoses of submerged macrophytes. It was one of the rarest components of vegetation of the studied area, patches of that association grew in small watercourses with the width not exceeding 3 m and characterized by the weak water flow. In that community Potamogeton pectinatus was a dominant and it covered 75 to 100% of the area. Among accompanying species, the surface water plants Lemna minor and L. gibba occurred more frequently. Floristically poorest patches of Potametum pectinati were those that existed in moderately saline habitats, in the range of Martwa Wis³a river basin (Table 9, relevés 2). Beside the massive occurrence of Fennel-leaved Pondweed, only the Duckweeds: Lemna gibba and L. minor appeared. Association: Potametum lucentis Hueck 1931 (Table 9, relevés 3-5) The association comprised of dense patches of submerged plants, among which Broad-leaved Pondweed dominates. In the studied area it was noted only in large natural and artificial watercourses Nogat river and canals: Cieplicówka and Œledziowy. The community occurred in flowing waters of about 2 m depth. Phytocoenoses of the discussed association were characterized by well developed submerged layer, built mostly by Potamogeton lucens. Quantitative and qualitative participation of the other species was insignificant. Among taxa appearing sporadically there were plants with floating leaves, such as: Nuphar lutea and Salvinia natans, as well Reed-swamp species, e.g. Phragmites australis and Typha latifolia. The exception was the patch of association growing in the Œledziowy canal (Table 9, relevé 4). That phytocoenosis was characterized by higher number of species 10. Three of them distinguished Potamogeton pusillus, Ceratophyllum demersum and Spirodela polyrhiza. Major participation of aquatic macrophytes was connected with water flow slower than in other watercourses, in which Potametum lucens was observed.

29 Vegetation of watercourses and their margins Table 9. Potametum pectinati Carstensen 1955 (relevés 1 2), Potametum lucentis Hueck 1931 (relevés 3 5), Potametum friesi Tomasz (relevés 6 8) and Potametum natantis Soó 1923 (relevés 9 11) Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type sn sn sc ln lc sn sc sc d lc d Cover of above water herb layer c (%) - - <1 <1 <1 - - < surface water herb layer c (%) < <5<1 submerged herb layer c! (%) Water depth (m) Relevé area (m ) Number of species Ch. Potametum pectinati Potamogeton pectinatus c! Ch. Potametum lucentis Potamogeton lucens c! Ch. Potametum friesi Potamogeton friesii c! Ch. Potametum natantis Potamogeton natans c! Ch. Nymphaeion*, Hottonion**, Potamion, Potametalia, Potametea Ceratophyllum demersum c! *Hydrocharis morsus-ranae c *Nuphar lutea Elodea canadensis c! Sporadic species: c : *Nymphaea alba 5(+),**Hottonia palustris 11 (+), c!: Potamogeton pusillus 3 (2), Potamogeton trichoides 8 (+) Accompanying species: Ch. Lemnetea minoris Lemna minor c Lemna trisulca c! Lemna gibba c Spirodela polyrhiza Salvinia natans Phragmites australis c Other species: Sporadic species: c: Glyceria maxima 3 (+), Sagittaria sagittifolia 3 (+), Typha latifolia 5(+), Hippuris vulgaris 8 (1), c!: Callitriche cophocarpa 1 (+)

30 30 Renata Afranowicz Association: Potametum friesi Tomasz (Table 9, relevés 6-8) The Flat-stalked Pondweed community was represented by facies phytocoenoses of submerged macrophytes with the biggest share of Potamogeton friesii. That community occurred rarely in the studied area. Patches of the association were noted in small rivers, canals and ditches of relatively slow water flow. Those phytocoenoses were connected with watercourses, characterized by muddy bottom and the water depth not exceeding 0.7 m. Studied phytocoenoses covered small areas up to 6 m. Potamogeton friesii was a dominant species and formed dense patches. It was accompanied by few small pleustophytes, which occurred with high abundance. They were diagnostic taxa of the class Lemnetea minoris: Lemna gibba, L. minor, L. trisulca and Spirodela polyrhiza. Association: Potametum natantis Soó 1923 (Table 9, relevés 9-11) The association was represented by communities of surface water plants, among which Floating Pondweed played dominant role. In the studied area the association was noted in few sites in natural and artificial watercourses. Small patches of Potametum natantis gave place to other communities of floating-leaf plants. In the discussed phytocoenoses Potamogeton natans was a dominant. Floristic composition of the patches was very poor only 4-5 taxa. Most of them usually appeared with low abundance and frequency. Only Lemna minor and Spirodela polyrhiza were occasionally more abundant (see Table 9). Association: Polygonetum natantis Soó 1927 (Table 10, relevés 1-3) That association was built by a floating form of Water Smartweed. Its small, well developed patches were noted in only few localities within the u³awy Wiœlame region, in rivers as well as in small canals and drainage ditches. The community was connected with slowly flowing waters, which depth usually didn t exceed 0.5 m, although in exceptional cases in larger rivers might reach 3 m. Phytocoenoses of Polygonetum natantis, similarly as Potametum natantis, were displaced by plant communities, e.g. Hydrocharitetum morsus-ranae. In the discussed community a relatively dense layer of surface water plants was built by Polygonum amphibium f. natans. Other accompanying species occurred seldom and with varied abundance. The only exception was Lemna minor, which was regular component of the studied phytocoenoses (see table 10). Association: Nymphoidetum peltatae (All. 1922) Bellot 1951 (Table 10, relevé 4) Phytocoenoses of Nymphoidetum peltatae were built by floating-leaf aquatic plants, among which Water fringe dominated. The association is particularly interesting on the regional or even country-wide scale, as it belongs to thermophilous communities of sub-oceanic-sub-mediterranean type of distribution range (Matuszkiewcz 2005). In the studied area the association was noted in natural watercourse, which is a branch of Wis³a Królewiecka river, located close to P³onino. The community grew in organic and muddy habitat, with water depth below 1 m.

31 Vegetation of watercourses and their margins Table 10. Polygonetum natantis Soó 1927 (relevés 1 3), Nymphoidetum peltatae (All. 1922) Bellot 1951 (relevé 4) and Myriophylletum verticillati Soó 1927 (relevés 5-8) Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type ln d sc ln sc sn sc sc Cover of above water herb layer c (%) - <1 - <1 5<1 - - surface water herb layer c (%) <520 submerged herb layer c! (%) Water depth (m) Relevé area (m ) Number of species Ch. Polygonetum natantis Polygonum amphibium f. natans c Ch. Nymphoidetum peltatae Nymphoides peltata c Ch. Myriophylletum verticillati Myriophyllum verticillatum c! Ch. Nymphaeion*, Hottonion**, Potamion, Potametalia, Potametea *Nuphar lutea c Elodea canadensis c! Ceratophyllum demersum Sporadic species: c!: *Nymphaea alba 1(+), Potamogeton pectinatus 1(2),*Hydrocharis morsus-ranae 6 (+), *Stratiotes aloides 6 (+) Accompanying species: Ch. Lemnetea minoris Lemna minor c Lemna trisulca c! Spirodela polyrhiza c Sporadic species: c : Lemna gibba 1 (+), Salvinia natans 6 (1), Wolffia arrhiza 8 (+) Other species: Alisma plantago-aquatica c Phragmites australis Sagittaria sagittifolia Sporadic species: c: Catabrosa aquatica 4 (+), Glyceria maxima 5(+), Sium latifolium 5(+), c!: Callitriche cophocarpa 2 (2)

32 32 Renata Afranowicz The patch of Nymphoidetum peltatae in Wis³a Królewiecka river covered area of ca. 40 m. Nymphoides peltata was a dominant and it achieved the highest abundance. Lemna minor and Nuphar lutea appeared as accompanying species. The submerged layer was weakly developed and it consisted of Ceratophyllum demersum and Lemna trisulca. The cover of submerged plants didn t exceed 20% (see table 10). Association: Myriophylletum verticillati Soó 1927 (Table 10, relevés 5-8) The association included dense phytocoenoses of submerged plants, with massive participation of Whorl-Leaf Watermilfoil. In the area of u³awy Wiœlane the community occurred rarely, in scattered localities. Well developed patches covered small areas, up to 8 m, located in natural and artificial watercourses. They appeared in places, where water depth didn t exceed 1 m and the movement of water was slow. The bottom of those watercourses was usually slightly silted. Myriophyllum verticillatum was a dominant species in those phytocoenoses. Among the accompanying species there was Lemna minor, which was a regular component of plant community, less frequently appeared: Elodea canadensis and Ceratophyllum demersum. Also some emerged plants, such as: Phragmites australis and Sagittaria sagittifolia, occurred sporadically (Table 10, relevés 5, 6). Myriophyllum verticillatum has ability to create turions, which play important role in vegetative spread and overwintering (Podbielkowski, Podbielkowska 1992; Podbielkowski, Tomaszewicz 1996). They permit phytocoenoses to last in the occupied localities and regenerate after mechanical hacking, or even desludging of watercourses (Table 10, relevés 5, 7, 8). Association: Hydrocharitetum morsus-ranae Langendonck 1935 (Table 11, relevés 1-13) The association of European Frogbit and Canadian Waterweed is a plant community built by aquatic macrophytes with floating and partly emerged leaves. It belongs to communities widespread in north-eastern part of u³awy Wiœlane. It was similarly developed in both natural and artificial watercourses, which were characterized by mainly stagnating water of small depth. Phytocoenoses were usually formed by aggregations of one of two characteristic species Hydrocharis morsus-ranae and Stratiotes aloides. Occasionally both taxa existed together, however in such situations one of them was a dominant (Photo 3). In natural watercourses, small-area phytocoenoses with European Frogbit were located in sheltered places close to Reed swamps, while in artificial ones they formed large patches that covered almost the whole watercourse width. Stratiotes aloides in both types of watercourses often covered the whole surface of water along significant distance. Massive occurrence of those two characteristic species usually precluded the appearance of other plants. The unoccupied spaces were taken by pleustophytes, usually: Lemna minor, L. gibba, Spirodela polyrhiza, less often Wolffia arrhiza and Salvinia natans. As cover of the above-water layer averaged 90%, the development of submerged macrophytes was limited. Among them occasionally

33 Vegetation of watercourses and their margins appeared: Lemna trisulca, Elodea canadensis and Potamogeton friesii. In the abovewater layer some helophytes were noted; they migrated from Reed swamp communities, neighbouring on the landward side. Table 11. Hydrocharitetum morsus-ranae Langendonck 1935 Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type ln sc sn sc sc d sc d d ln sc d ln Cover of above water herb layer c (%) surface water herb layer c (%) submerged herb layer c! (%) Water depth (m) Relevé area (m ) Number of species Ch. Hydrocharitetum morsus-ranae Hydrocharis morsus-ranae c Stratiotes aloides Ch. Nymphaeion, Potametalia, Potametea Elodea canadensis c! Potamogeton friesii Hottonia palustris c Sporadic species: c : Nuphar lutea 1(+), Nymphaea alba 1(+), Callitriche cophocarpa 6(1), c!: Potamogeton crispus 3 (1), Potamogeton filiformis 5(+), Potamogeton sp. 12 (+) Accompanying species: Ch. Lemnetea minoris Lemna minor c Lemna trisulca c! Spirodela polyrhiza c Lemna gibba Salvinia natans Sporadic species: c : Wolffia arrhiza 7 (+) Ch. Phragmitetea Sagittaria sagittifolia c Glyceria maxima Sporadic species: Galium palustre 6(+), Sparganium erectum 6(+), Typha latifolia 6(+), Alisma plantagoaquatica 13 (+), Glyceria fluitans 13 (+), Phragmites australis 13 (+), Sium latifolium 13 (+) Other species: Sporadic species: c: Calystegia sepium 13 (+), Lythrum salicaria 13 (+)

34 34 Renata Afranowicz Phytocoenoses of Hydrocharitetum morsus-ranae played an important role in overgrowing of watercourses. After maintaining actions a quick regeneration of dense patches of that community was observed (Table 11, relevés 4, 5). Association: Nupharo-Nymphaeetum albae Tomasz (Table 12, relevés 1-10) The association consists of species with large floating leaves: Yellow Pond Lily and Water Lily. Its phytocoenoses occurred in large rivers, mainly in: Nogat, Szkarpawa, Tina, Tuga and Izbowa acha as well as in wide artificial canals: Cieplicówka and Panieñski. Table 12. Nupharo-Nymphaeetum albae Tomasz Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type ln lc sc ln ln ln ln lc ln ln Cover of above water herb layer c (%) < surface water herb layer c (%) submerged herb layer c! (%) - < <1 <1 <1 - - <1 Water depth (m) Relevé area (m ) Number of species Ch. Nupharo-Nymphaeetum albae Nuphar lutea c Nymphaea alba Ch. Nymphaeion, Potametalia, Potametea Potamogeton perfoliatus c! Ceratophyllum demersum Hydrocharis morsus-ranae c Sporadic species: c : Stratiotes aloides 3 (+), c!: Myriophyllum verticillatum 3 (+) Accompanying species: Ch. Lemnetea minoris Salvinia natans c Spirodela polyrhiza Lemna minor Lemna trisulca c! Ch. Phragmitetea Sagittaria sagittifolia c Sporadic species: Typha latifolia 2 (+)

35 Vegetation of watercourses and their margins Nuphar lutea and/or Nymphaea alba dominated in the structure of immense, multi-ares patches (Photo 4). Among other components of the surface water layer there were usually pleustophytes: Salvinia natans, Spirodela polyrhiza and Lemna minor. In the utmost cases phytocoenoses were built exclusively by Yellow Pond Lily and Water Lily. The submerged plant layer was formed mostly by: Ceratophyllum demersum, Potamogeton perfoliatus and Lemna trisulca. Cover of that layer usually didn t exceed 20% (see Table 12). The appearance of Nuphar lutea and Nymphaea alba was not limited to large watercourses, as they occurred also in smaller canals and drainage ditches. In such circumstances they formed small patches of their own association or were components of other aquatic communities as accompanying species. Association: Hottonietum palustris R.Tx (Table 13, relevés 1-4) That association was built by partly emerged aquatic plants. Typically developed patches of Hottonietum palustris appeared in localities scattered over Wis³a river delta. They were noted only in small, periodically drying up watercourses of the width not exceeding 2 m and water depth reaching 0.4 m. Table 13. Hottonietum palustris R.Tx Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type d d d d Cover of above water herb layer c(%) surface water herb layer c (%) submerged herb layer c!(%) Water depth (m) Relevé area (m ) Number of species Ch. Hottonietum palustris Hottonia palustris c Callitriche cophocarpa... 3 Ch. Hottonion, Potametalia, Potametea Hydrocharis morsus-ranae c Accompanying species: Ch. Lemnetea minoris Lemna minor c Sporadic species: c!: Lemna trisulca 1 (3) Ch. Phragmitetea Equisetum fluviatile c Sporadic species: Alisma plantago-aquatica 2 (+), Glyceria fluitans 3 (+), Glyceria maxima 3 (+), Sium latifolium 3 (+)

36 36 Renata Afranowicz Phytocoenoses of that association were floristically poor and consisted of 4-5 taxa. Hottonia palustris was a dominant, and from other characteristic species only Callitriche cophocarpa was noted. Among accompanying species Lemna minor occurred more frequently and L. trisulca in singular patches (see Table 13). Association: Sparganietum erecti Roll 1938 (Table 14, relevés 1-10) The Branched Bur-reed association was a relatively common community in the u³awy Wiœlane. It occurred in both natural and artificial watercourses and usually adjoins aquatic communities. Phytocoenoses appeared in form of weakly dense, small, one- or two-layer patches, which height reached ca. 1 m. The characteristic species Sparganium erectum was usually a dominant. Accompanying species occurred with varied frequency and abundance. In natural watercourses (Table 14, relevés 1-2) and in some artificial ones (Table 14, relevés 3-4) major participation had species of the class Lemnetea minoris, which build the surface and/or submerged layers. In the other relevés representing phytocoenoses developed in artificial watercourses, species of that class didn t appear, while quite common were taxa of Phragmitetea as well as other helophytes, which were regular components of Reed-swamp communities. Association: Typhetum angustifoliae (Allorge 1922) Soó 1927 (Table 15, relevés 1-7) The Narrow Leaf Cattail swamp was a floristically poor community, reaching up to 2.5 m height. It occurred rather frequently in the studied area, but only on large, natural rivers of u³awy, among others on: Nogat, Szkarpawa, Martwa Wis³a and Linawa. Those rivers were characterized by sandy, sometimes slightly muddy bottom. According to the occurrence and floristical composition, two variants of the association were distinguished. The first one occurred in some distance of watercourse bank, in waters of ca. 1.5 m depth. In those patches species of classes: Lemnetea minoris and Potametea were more abundant (Table 15, relevés 1-3). And the other variant was observed in the bankside area, characterized by minor water depth about 0.8 m. In floristic composition of those phytocoenoses more frequent were species characteristic for the class Phragmitetea as well as other helophytes (Table 15, relevés 4-6). Association: Typhetum latifoliae Soó 1927 (Table 16, relevés 1-20) The Common Cattail swamp was a very common plant community in the Wis³a river delta. It grew within the whole studied area in watercourses of different types. The floristically richest phytocoenoses of that association occurred in the contact area of aquatic and other Reed-swamp communities (Table 16, relevés 4, 5, 8). Occasionally, mainly in watercourses that are seasonally drying up, patches less reach in species appeared (Table 16, relevés 11, 14, 15, 17). Those phytocoenoses were characterized by the lack of hydrophytes and minor participation of helophytes.

37 Vegetation of watercourses and their margins Table 14. Sparganietum erecti Roll 1938 Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type sn sn d sc lc d sc sc d d Cover of above water herb layer c (%) surface water herb layer c (%) 40 <1 - < submerged herb layer c! (%) <1 < Water depth (m) Relevé area (m ) Number of species Ch. Sparganietum erecti Sparganium erectum c Ch. Phragmition, Phragmitetalia, Phragmitetea Alisma plantago-aquatica c Glyceria maxima Sium latifolium Galium palustre Rumex hydrolapathum Typha latifolia Sporadic species: Rorippa amphibia 3 (+), Sagittaria sagittifolia 3 (+), Veronica anagallis-aquatica 3 (+), Iris pseudacorus 5(+), Oenanthe aquatica 6 (+), Butomus umbellatus 9 (+), Carex pseudocyperus 9 (+), Phragmites australis 10 (+) Accompanying species: Ch. Lemnetea minoris Lemna minor c Lemna trisulca c! Spirodela polyrhiza c Sporadic species: c : Lemna gibba 1 (+) Ch. Potametea Sporadic species: c : Callitriche cophocarpa 3 (+), Ceratophyllum demersum 3 (+), Nuphar lutea 3 (+), Hydrocharis morsus-ranae 4 (+), c!: Elodea canadensis 3 (+), Potamogeton pectinatus 3 (3) Other species: Myosotis palustris c Bidens cernua Equisetum palustre Lythrum salicaria Lycopus europaeus Sporadic species: Peucedanum palustre 3(+), Typha latifolia 3(+), Calystegia sepium 5(+), Mentha aquatica 5(+), Solanum dulcamara 5(+), Bidens tripartita 6 (+), Epilobium hirsutum 6 (+), Ranunculus repens 6 (+)

38 38 Renata Afranowicz Table 15. Typhetum angustifoliae (Allorge 1922) Soó 1927 Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type ln ln ln ln ln ln ln Cover of above water herb layer c(%) surface water herb layer c (%) < submerged herb layer c!(%) < Water depth (m) Relevé area (m ) Number of species Ch. Typhetum angustifoliae Typha angustifolia c Ch. Phragmition, Phragmitetalia, Phragmitetea Phragmites australis c Glyceria maxima Rumex hydrolapathum Sporadic species: Sagittaria sagittifolia 1 (1), Sium latifolium 2 (+), Carex gracilis 4 (+), Carex pseudocyperus 4 (+), Oenanthe aquatica 4 (+), Sparganium emersum 4 (+), Iris pseudacorus 5(+), Bolboschoenus maritimus 6 (+), Eleocharis palustris 6 (1), Schoenoplectus lacustris 6 (+), Schoenoplectus tabernaemontani 6 (+) Acommpanying species: Ch. Lemnetea minoris Lemna minor c Spirodela polyrhiza Lemna trisulca c! Sporadic species: c : Salvinia natans 1 (+) Ch. Potametea Hydrocharis morsus-ranae c Nuphar lutea Sporadic species: c : Nymphaea alba 7 (+), c!: Ceratophyllum demersum 1 (+), Potamogeton lucens 1 (+) Other species: Sporadic species: Lythrum salicaria 2 (+), Equisetum palustre 4 (+), Lycopus europaeus 4 (+), Myosotis palustris 4 (+), Polygonum hydropiper 4 (+), Rumex palustris 4 (+), Agrostis stolonifera 6 (2), Aster tripolium 6 (+), Atriplex littoralis 6 (+), Hippuris vulgaris 6 (+)

39 Table 16. Typhetum latifoliae Soó 1927 Successive number of relevé Number of relevé in the field Date: day month year Localitynumber (see chapter 2.1) Watercourse type sc ln d ln sc ln d d sc d d d sc sc d d d d d d Cover of above water herb layer c (%) surface water herb layer c (%) < submerged herb layer c! (%) Water depth (m) < Relevé area (m ) Number of species Ch. Typhetum latifoliae Typha latifolia c Ch. Phragmition, Phragmitetalia, Phragmitetea Alisma plantago-aquatica c Glyceria maxima Rumex hydrolapathum Sparganium erectum Rorippa amphibia Phalaris arundinacea Galium palustre Sium latifolium Phragmites australis Carex acutiformis Cicuta virosa Acorus calamus

40 Bolboschoenus maritimus Glyceria fluitans Iris pseudacorus Carex cuprina Sporadic species: Eleocharis palustris 5 (+), Carex gracilis 12 (1), Equisetum fluviatile 12 (1), Carex vulpina 16 (+), Carex pseudocyperus 20 (+) Accomanying species: Ch. Lemnetea minoris Lemna minor c Spirodela polyrhiza Lemna trisulca c! Salvinia natans c Ch. Potametea Hydrocharis morsus-ranae c Ceratophyllum demersum c! Callitriche cophocarpa c Sporadic species: c : Nuphar lutea 6 (+), Nymphaea alba 6 (+), c!:potamogeton trichoides 9 (1) Other species: Lythrum salicaria c Symphytum officinale Solanum dulcamara Equisetum palustre Ranunculus sceleratus Myosotis palustris Calystegia sepium Juncus effusus Epilobium hirsutum Bidens cernua Polygonum amphibium f. terrestre Sporadic species: Mentha aquatica 2 (+), Stachys palustris 2 (+), Lycopus europaeus 4 (+), Polygonum mite 5 (+), Mentha arvensis 8 (+), Bidens tripartita 13 (+), Peucedanum palustre 13 (+), Agrostis stolonifera 16 (1), Alopecurus aequalis 16 (1), Juncus articulatus 16 (+), Juncus bufonius 16 (+), Juncus inflexus 16 (1), Juncus tenuis 16 (+), Equisetum arvense 19 (+), Lysimachia vulgaris 19 (+), Scirpus sylvaticus 19 (+)

41 Vegetation of watercourses and their margins In natural watercourses the surface layer was better developed (Table 16, relevés 2-4, 7) and it was built by Spirodela polyrhiza, Lemna minor and sometimes Salvinia natans. Phytocoenoses of Typhetum latifoliae often occurred also in shallow drainage ditches, which depth didn t exceed 0.4 m (Photo 5). Those small patches (up to 10 m ) usually covered the whole width of the ditch. Their floristic composition consisted mainly from: Alisma plantago-aquatica, Equisetum palustre, Lythrum salicaria as well as many other swamp species, which appeared sporadically. Association: Phragmitetum australis (Gams 1927) Schmale 1939 (Table 17-23) The Common Reed swamp was the most widespread swamp community in the u³awy Wiœlane region. It occurred along the banks as well as in flood zones of all types of watercourses in the whole studied area. Phytocoenoses consisted of one, two or three plant layers. The highest layer was built mainly by Phragmites australis and its cover varied from 20 to 90%. The total number of species found in herb layer was 196 and among them were species of other Reed swamps as well as those of meadows, alder forests, tall herb, ruderal and segetal communities. Diversity of the structure and floristic composition of the observed phytocoenoses was associated with habitat conditions and influence of the neighbourhood. In Reed-swamp phytocoenoses located along natural watercourses altogether 161 species were found, among which 63% were plants of wet habitats. The opposite situation was observed in patches developed along ditches and canals. In those communities over half of 136 species consisted of species from dryer habitats. The significant number of such species was affected by close vicinity of farmlands and roadsides, however those plants played slight role in the analyzed patches. Particular phytocoenoses were built by different number of species. The poor ones consisted of less than 10 taxa. Quite often it was connected with Common Reed burns in the spring, made on the banks of watercourses located close to farmlands. The richest patches comprised of even 43 species. They developed on fertile soils of flood plains of rivers such as: Martwa Wis³a, Balewka, Szkarpawa, Nogat or Cieplicówka canal. The patches were mostly built by species of wet habitats, especially those from the class Phragmitetea. Multi-species Reed-swamp communities occurred also on the banks of drainage ditches, although they had slightly different floristic composition from those described above. They were also characterized by greater participation of species from dryer habitats. Altogether 7 different variants of the Common Reed community were identified on the banks and in flood plains of the studied watercourses. Variant with aquatic species (Table 17, relevés 1-11) That variant of the Common Reed swamps often occurred on permanently flooded banks of mostly natural watercourses, characterized by the muddy bottom and water depth reaching 1.5 m. In zonation of plant communities they

42 42 Renata Afranowicz strictly bordered on aquatic communities or other Reed-swamps occurring in deeper parts of watercourses, e.g. Typhetum angustifoliae and Scirpetum maritimi. Stands of that form of Phragmitetum australis was distinguished by the occurrence of aquatic species. Among them the most frequent was Lemna minor, while others, like: Lemna trisulca, Hydrocharis morsus-ranae or Stratiotes aloides, appeared sporadically. The surface water layer usually didn t cover much area and only in some patches was well developed up to 40% (Table 17, relevés 1-2). At the same time participation of the swamp species was small. Phytocoenoses representing the analyzed variant were characterized by well developed herb layer (Table 17, relevés 3-8). They were built by species of Reed swamps, alder forests and other communities associated with waters banks. The most frequent were: Carex riparia and C. acutiformis as well as Iris pseudacorus, Solanum dulcamara, Calystegia sepium and Urtica dioica. Patches of Phragmitetum australis occurring in the flood zone of drainage ditches had a richer floristic composition (Table 17, relevé 9). Higher species diversity was associated with appearance of plants from adjacent areas, as a consequence of unstable water conditions, i.e. frequent drying up of the watercourses. Stands growing in deep water were characterized by the poorest species composition (Table 17, relevés 1-11) or had a form of mono-species aggregations of Phragmites australis. In both cases Common Reed built loose, up to 2 m high phytocoenoses. Table 17. Phragmitetum australis variant with aquatic species Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type ln ln sn sc d ln ln ln sn sn ln Cover of above water herb layer c/c (%) Cover of above water herb layer c /c! (%) 30/. 20/. <5/. <5/. <5/. 5/. 20/. <5/<5 -./<5 <5/. Relevé area (m ) Number of species Ch. Phragmitetum australis Phragmites australis D. of the variant Lemna minor c Spirodela polyrhiza Salvinia natans Ceratophyllum demersum c! Hydrocharis morsus-ranae c

43 Vegetation of watercourses and their margins Lemna trisulca c! Stratiotes aloides c Sporadic species: c : Nymphaea alba 11 (+) Ch. Phragmition, Phragmitetalia, Phragmitetea Iris pseudacorus c, c Typha latifolia Carex acutiformis Carex riparia Typha angustifolia Carex pseudocyperus Glyceria maxima Acorus calamus Carex paniculata Sporadic species: Alisma plantago-aquatica 5(+), Poa palustris 5(+), Sagittaria sagittifolia 6 (+), Schoenoplectus tabernaemontani 7 (1), Sium latifolium 7 (+), Rumex hydrolapathum 7 (+), Bolboschoenus maritimus 8 (+), Rorippa amphibia 9 (+), Galium palustre 10 (+), Phalaris arundinacea 10 (+), Carex gracilis 11 (+), Cicuta virosa 11 (+) Accomanying species: Ch. Alnetea glutinosae Solanum dulcamara c, c Lycopus europaeus Ch., D. Artemisietea vulgaris (Convolvuletalia sepium*) *Calystegia sepium c, c Urtica dioica Cirsium arvense *Symphytum officinale Rubus caesius Sporadic species: *Angelica archangelica subsp. litoralis 1 (+), Actium lappa 2 (+), Carduus crispus 2 (+), *Cuscuta europaea 2 (1) Ch. Molinio-Arrhenatheretea Lysimachia vulgaris c, c Lythrum salicaria Vicia cracca Stachys palustris Sporadic species: Geranium pratense 1 (+), Elymus repens 5(1), Mentha longifolia 5(+), Caltha palustris 8 (+), Equisetum palustre 9 (+) Other species: Polygonum amphibium f. terrestre c, c Aegopodium podagraria Epilobium hirsutum Sonchus arvensis Sporadic species: Sonchus palustris 1 (1), Polygonum hydropiper 3 (+), Polygonum minus 3 (+), Galeopsis bifida 5(+), Juncus effusus 5(1), Mentha xverticillata 5(1), Salix fragilis (juv.) 5(2), Scirpus sylvaticus 5(1), Equisetum arvense 7 (+), Bidens cernua 11 (+), Vicia sepium 11 (+)

44 44 Renata Afranowicz Halophilous variant (Table 18, relevés 1-6) Specific forms of the Common Reed association were located within the flood zone of the Martwa Wis³a river. They were distinguished by the appearance of halophilous plants. The origin of those phytocoenoses was connected with appearance and gradual overgrowing by Phragmites australis on the habitats of salt-marsh community Juncetum gerardi. Phytocoenoses of that variant were characterized by usually low cover of Common Reed. Significant role was played by halophytes and plants associated with salt-marsh habitats, able to tolerate the enlarged content of sodium chlordane in the soil (see Zarzycki et al. 2002). Among them the highest abundance had: Agrostis stolonifera, Glaux maritima, Atriplex prostrata and Juncus compressus (see Table 18). Also the other species like: Plantago winteri, Aster tripolium, Triglochin maritimum, Atriplex littoralis, Potentilla anserina and Hippuris vulgaris were noted. Their total cover reached 40-60%. The other components of the herb layer took small role in the community formation. Table 18. Phragmitetum australis halophilous variant Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type ln ln ln lc ln ln Cover of above water herb layer c/c (%) Relevé area (m ) Number of species Ch. Phragmitetum australis Phragmites australis c, c D. of the variant Plantago winteri c, c Triglochin maritimum Atriplex littoralis Aster tripolium Bolboschoenus maritimus Schoenoplectus tabernaemontani Sporadic species: Glaux maritima 2 (+) Ch. Phragmition, Phragmitetalia, Phragmitetea Hippuris vulgaris c, c Eleocharis palustris Carex vulpina Iris pseudacorus

45 Vegetation of watercourses and their margins Sporadic species: Carex riparia 1(+),Sium latifolium 1(+), Galium palustre 2(+),Ranunculus lingua 2(+), Schoenoplectus lacustris 3 (+), Rumex hydrolapathum 6 (+) Accompanying species: Ch., D. Artemisietea vulgaris (Convolvuletalia sepium*) *Calystegia sepium c, c Cirsium arvense Sporadic species: Senecio fluviatilis 1 (+), Urtica dioica 1 (+), *Angelica archangelica subsp. litoralis 2 (+), Galeopsis pubescens 2 (+), Galium aparine 2 (+) Ch. Molinio-Arrhenatheretea Agrostis stolonifera c, c Potentilla anserina Elymus repens Agrostis gigantea Vicia cracca Sporadic species: Carex cuprina 1 (+), Geranium pratense 1 (+), Lysimachia vulgaris 1 (+), Rumex crispus 1 (+) Other species Juncus compressus c, c Atriplex prostrata Sonchus arvensis Sonchus oleraceus Polygonum mite Rumex sanguineus Sonchus palustris Sporadic species: Bromus inermis 1 (+), Calamagrostis canescens 1 (1), Plantago intermedia 1 (+), Polygonum aviculare 1 (+), Tanacetum vulgare 1 (+), Carex pairae 2 (+), Polygonum amphibium f. terrestre 2 (+), Taraxacum officinale 2 (+), Juncus bufonius 5(+) Variant with Agrostis gigantea (Table 19, relevés 1-18) This type of phytocoenoses developed more frequently along ditches than natural watercourses. According to watercourse size, patches had a form of rather narrow strips on the banks of drainage ditches or large-area phytocoenoses located on big rivers and canals. That variant of the Reed-swamps was often connected with mowing of banks of the artificial watercourses. The characteristic species of that Reed swamps Phragmites australis had a low cover. Distinctive for that variant was significant participation of other grasses: Agrostis gigantea, A. stolonifera, Phalaris arundinacea and Calamagrostis canescens. They usually covered up to 30-40%. In some patches, among other monocotyledon species, more frequent were sedges, especially Carex riparia and C. acutiformis. Abundant were also: Urtica dioica, Symphytum officinale, Cirsium arvense, Lythrum salicaria, Lysimachia vulgaris and Polygonum amphibium f. terrestre. In the herb layer, which on average consisted of 16 species per relevé, other taxa were noted with varied frequency and quantity (see Table 19).

46 Table 19. Phragmitetum australis variant with Agrostis gigantea Successive number of relevé Number of relevé in the field Date: day month year Localitynumber (see chapter 2.1) Watercourse type d d d d ln ln d d ln ln d d d d lc lc d ln Cover of above water herb layer c/c (%) Relevé area (m ) Number of species Ch. Phragmitetum australis Phragmites australis D. of the variant Agrostis gigantea Agrostis stolonifera Ch. Phragmition, Phragmitetalia, Phragmitetea Phalaris arundinacea c, c Carex acutiformis Poa palustris Iris pseudacorus Carex riparia Carex pseudocyperus Scutellaria galericulata Galium palustre Carex paniculata

47 Sporadic species: Peucedanum palustre 3 (+), Typha latifolia 6 (+), Carex gracilis 7 (+), Sium latifolium 10 (+) Accompanying species: Ch. Alnetea glutinosae Calamagrostis canescens c, c Lycopus europaeus Sporadic species: Solanum dulcamara 5 (+) Ch., D. Artemisietea vulgaris (Convolvuletalia sepium*) Urtica dioica c, c *Symphytum officinale Cirsium arvense Glechoma hederacea * Calystegia sepium Artemisia vulgaris Carduus crispus Galium aparine Myosoton aquaticum Cirsium vulgare Fallopia convolvulus Senecio fluviatilis Rubus caesius Solidago gigantea Angelica sylvestris Anthriscus sylvestris Sporadic species: Linaria vulgaris 7(+), Medicago lupulina 7 (+), Melandrium album 7 (+), *Eupatorium cannabinum 10 (+), Actium lappa 18 (+) Ch. Molinio-Arrhenatheretea Lythrum salicaria c, c Vicia cracca Lysimachia vulgaris Deschampsia caespitosa

48 Equisetum palustre Stachys palustris Filipendula ulmaria Elymus repens Ranunculus repens Potentilla anserina Lathyrus palustris Mentha longifolia Carex hirta Cirsium oleraceum Lathyrus pratensis Sporadic species: Achillea millefolium 7 (+), Poa trivialis 7 (2), Plantago lanceolata 7 (+), Plantago major 7 (+), Rorippa sylvestris 7 (+), Rumex crispus 7 (+), Trifolium pratense 7 (+), Alopecurus pratensis 12 (+) Other species: Polygonum amphibium f. terrestre c, c Juncus effusus Calamagrostis epigejos Epilobium hirsutum Senecio paludosus Sonchus oleraceus Chenopodium polyspermum Taraxacum officinale Epilobium montanum Mentha arvensis Thalictrum aquilegiifolium Scirpus sylvaticus Sporadic species: Dryopteris carthusiana 3 (+), Hypericum tetrapterum 3 (+), Anthoxanthum odoratum 7 (1), Equisetum arvense 7 (+), Mentha xverticillata 7 (1), Rorippa palustris 7 (+), Aegopodium podagraria 9 (2), Thalictrum flavum 9 (+), Vicia sepium 9 (+), Sonchus palustris 10 (+), Galinsoga ciliata 12 (+), Polygonum minus 15 (+), Valeriana officinalis 16 (+), Chenopodium album 17 (+), Galinsoga ciliata 17 (+), Matricaria maritima subsp. inodora 17 (+)

49 Vegetation of watercourses and their margins Typical variant with tall herbs (Table 20, relevés 1-18) Large-area phytocoenoses representing that variant grew on the extensive fertile terraces of rivers: Nogat, Szkarpawa, Fiszewka and large canals: Elbl¹ski and Cieplicówka. Well developed, but smaller patches occurred also on drainage ditches. That floristically rich variant of the Common Reed association had a physiognomy of tall herb-reed swamp community, characterized by significant participation of dicotyledonous perennials. They were mainly: Calystegia sepium, Lysimachia vulgaris, Eupatorium cannabinum, Filipendula ulmaria and sometimes: Senecio paludosus, S. fluviatilis and Solidago gigantea. In the three-layer structure of the community other accompanying species, especially from the classes Phragmitetea, Molinio-Arrhenatheretea and Artemisietea vulgaris, were frequent (see Table 20). The floristic composition of particular phytocoenoses consisted of few to over a dozen taxa (on average 17 species per patch). Nitrophilous variant with tall herbs (Table 21, relevés 1-12) This is a local variant of Common Reed association, widespread along both natural and artificial watercourses. Phytocoenoses were characterized by complex structure and rich floristic composition. The upper layer was built by Phragmites australis, which formed not very dense stands. Apart from the previously described typical variant with tall herbs, here the major quantitative and qualitative participation had plants of fertile habitats, like nitrophytes: Urtica dioica and Cirsium arvense. There was also a large group of accompanying species, although they appeared sporadically and didn t play any significant role in the community formation. That variant was referred to Urtico-Phragmitetum, which was distinguished by the occurrence of nitrophytes. Variant with Calystegia sepium (Table 22, relevés 1-18) This is a low Reed swamp community, found often on the banks of natural and artificial watercourses. It was distinguished by regular presence of Calystegia sepium, which quite abundant occurrence gave a specific physiognomy to the community individuals of Common Reed, which grew in loose patches, were entangled by the shoots of Hedge False Bindweed. The described variant of Phragmitetum australis was also characterized by regular participation of nitrophilous species: Urtica dioica and Cirsium arvense. In some stands (Table 22, relevés 1-9) the tall herb species, such as Senecio fluviatilis or Lythrum salicaria, occurred sporadically and they were used by Calystegia sepium as a suitable support.

50 Table 20. Phragmitetum asutralis typical variant with tall herbs Successive number of relevé Number of relevé in the field Date: day month year Localitynumber (see chapter 2.1) Watercourse type ln ln lc ln ln ln ln ln ln sn sn ln sn ln ln d ln ln Cover of above water herb layer c/c (%) Relevé area (m ) Number of species Ch. Phragmitetum australis Phragmites australis D. of the variant Calystegia sepium c, c Lysimachia vulgaris Lythrum salicaria Filipendula ulmaria Eupatorium cannabinum Solidago gigantea Angelica sylvestris Senecio paludosus Senecio fluviatilis Sporadic species: Thalictrum aquilegiifolium 11 (1) Ch. Phragmition, Phragmitetalia, Phragmitetea Iris pseudacorus c, c

51 Phalaris arundinacea Acorus calamus Carex acutiformis Galium palustre Carex riparia Carex paniculata Poa palustris Carex gracilis Bolboschoenus maritimus Rumex hydrolapathum Typha latifolia Sporadic species: Alisma plantago-aquatica 1 (+), Carex disticha 1 (3), Carex vulpina 1 (+), Scutellaria galericulata 1 (+), Glyceria maxima 2 (+), Peucedanum palustre 9 (+), Rorippa amphibia 9 (+), Cicuta virosa 13 (+), Sium latifolium 14 (1) Accompanying species: Ch. Alnetea glutinosae Lycopus europaeus c, c Solanum dulcamara Sporadic species: Calamagrostis canescens 5 (2) Ch., D. Artemisietea vulgaris (Convolvuletalia sepium*) Urtica dioica c, c *Symphytum officinale Cirsium arvense Rubus caesius Galium aparine Glechoma hederacea Sporadic species: Carduus crispus 9 (+), Myosoton aquaticum 9 (1), Anthriscus sylvestris 10 (+), Artemisia vulgaris 10 (1), *Cuscuta europaea 10 (2)

52 Ch. Molinio-Arrhenatheretea Stachys palustris c, c Vicia cracca Caltha palustris Equisetum palustre Myosotis palustris Ranunculus repens Heracleum sibiricum Lathyrus pratensis Sporadic species: Alopecurus pratensis 1 (+), Rorippa sylvestris 1 (+), Geranium pratense 3 (+) Other species: Polygonum amphibium f. terrestre c, c Humulus lupulus Sonchus palustris Angelica archangelica subsp. archangelica Rorippa palustris Calamagrostis epigejos Mentha aquatica Equisetum arvense Bidens frondosa Tanacetum vulgare Polygonum minus Sporadic species: Achillea ptarmica 1 (+), Juncus articulatus 1 (+), Juncus effusus 1 (+), Polygonum mite 1 (+), Rumex conglomeratus 1 (+), Salix purpurea 1 (+), Trifolium medium 1 (+), Veronica longifolia 1 (+), Thalictrum flavum 2 (+), Valeriana officinalis 3 (+), Chaerophyllum bulbosum 4 (+), Sonchus arvensis 4 (+), Hypericum perforatum 10 (1), Scirpus sylvaticus 13 (+), Sparganium emersum 14 (+), Aegopodium podagraria 17 (1), Cucubalus baccifer 17 (1), Atriplex prostrata 17 (+)

53 Vegetation of watercourses and their margins Table 21. Phragmitetum asutralis nitrophilous variant with tall herbs Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type sc lc ln d d ln lc d d sc ln sn c/c Cover of above water herb layer (%) Relevé area (m ) Number of species Ch. Phragmitetum australis Phragmites australis D. of the variant Lythrum salicaria c, c Calystegia sepium Lysimachia vulgaris Filipendula ulmaria Senecio fluviatilis Eupatorium cannabinum Sporadic species: Angelica sylvestris 2 (+), Solidago gigantea 2 (2), Thalictrum aquilegiifolium 6 (+) Ch. Phragmition, Phragmitetalia, Phragmitetea Carex acutiformis c, c Iris pseudacorus Phalaris arundinacea Poa palustris Galium palustre Carex riparia Sporadic species: Scutellaria galericulata 4 (+), Glyceria maxima 11 (+), Typha latifolia 12 (+) Accompanying species: Ch. Alnetea glutinosae Solanum dulcamara c, c Lycopus europaeus Sporadic species: Calamagrostis canescens 4 (1) Ch., D. Artemisietea vulgaris (Convolvuletalia sepium*) Urtica dioica c, c Cirsium arvense *Symphytum officinale Rubus caesius Anthriscus sylvestris

54 54 Renata Afranowicz Carduus crispus Myosoton aquaticum Galium aparine Glechoma hederacea Sporadic species: Arctium lappa 1 (+), Armoracia rusticana 2 (+), *Cuscuta europaea 9 (1) Ch. Molinio-Arrhenatheretea Vicia cracca c, c Lathyrus pratensis Carex hirta Deschampsia caespitosa Stachys palustris Elymus repens Equisetum palustre Sporadic species: Alopecurus pratensis 1 (+), Carex cuprina 1 (3), Cirsium oleraceum 1 (+), Festuca pratensis 1 (+), Lotus uliginosus 1 (+), Lysimachia nummularia 1 (1), Phleum pratense 1 (+), Poa pratensis 1 (+), Potentilla anserina 1 (+), Ranunculus acris 1 (+), Ranunculus repens 1 (+), Rumex acetosa 1 (+), Lathyrus palustris 5(+), Mentha longifolia 6 (+), Myosotis palustris 11 (+) Other species: Epilobium hirsutum c, c Polygonum amphibium f. terrestre Sonchus palustris Equisetum pratense Vicia sepium Aegopodium podagraria Cucubalus baccifer Sporadic species: Carex ovina 1(+),Juncus articulatus 1(+),Juncus effusus 1(+),Lupinus polyphyllus 1(+), Scirpus sylvaticus 1 (+), Valeriana officinalis 1 (+), Atriplex prostrata 3 (+), Bidens tripartita 3 (+), Peucedanum palustre 3(+),Chenopodium album 5(+), Chenopodium polyspermum 5(+), Galinsoga ciliata 5(+), Taraxacum officinale 5(+), Calamagrostis epigejos 6(+), Humulus lupulus 9(+),Tanacetum vulgare 11 (+)

55 Table 22. Phragmitetum australis variant with Calystegia sepium Successive number of relevé Number of relevé in the field Date: day month year Localitynumber (see chapter 2.1) Watercourse type sc ln lc lc ln d sn sn sc d lc sc sc lc ln sc sc ln Cover of above water herb layer c, c (%) Relevé area (m ) Number of species Ch. Phragmitetum australis Phragmites australis c, c D. of the variant Calystegia sepium c, c Senecio fluviatilis Lythrum salicaria Eupatorium cannabinum Sporadic species: Solidago gigantea 2 (1), Angelica sylvestris 3 (+), Filipendula ulmaria 3 (+) Ch. Phragmition, Phragmitetalia, Phragmitetea Poa palustris c, c Iris pseudacorus Bolboschoenus maritimus Carex riparia Phalaris arundinacea Scutellaria galericulata

56 Sium latifolium Sporadic species: Carex acutiformis 5 (+), Galium palustre 9 (+), Carex gracilis 11 (1), Rumex hydrolapathum 12 (+), Carex elata 16 (2), Acorus calamus 18 (1), Berula erecta 18 (+), Cicuta virosa 18 (+), Glyceria maxima 18 (+), Oenanthe aqatica 18 (+), Rorippa amphibia 18 (+) Accompanying species: Ch. Alnetea glutinosae Lycopus europaeus c, c Sporadic species: Calamagrostis canescens 1 (1), Solanum dulcamara 12 (+) Ch., D. Artemisietea vulgaris (Convolvuletalia sepium*) Urtica dioica c, c *Symphytum officinale Cirsium arvense Carduus crispus Galium aparine Glechoma hederacea Anthriscus sylvestris Rubus caesius Artemisia vulgaris Actium lappa Lactuca serriola Sporadic species: Myosoton aquaticum 4 (+), Lamium album 9 (+), Galeopsis pubescens 12 (+) Ch. Molinio-Arrhenatheretea Vicia cracca c, c Stachys palustris Equisetum palustre Elymus repens Geranium pratense

57 Alopecurus pratensis Ranunculus repens Heracleum sibiricum Sporadic species: Mentha longifolia 2 (1), Lathyrus pratensis 3 (+), Caltha palustris 5 (+), Achillea millefolium 15 (+), Dactylis glomerata 15 (+), Phleum pratense 15 (+), Myosotis palustris 18 (+) Other species: Tanacetum vulgare c, c Arctium lappa Epilobium hirsutum Equisetum arvense Polygonum amphibium f. terrestre Sonchus palustris Chenopodium album Cucubalus baccifer Sonchus oleraceus Sonchus arvensis Galium mollugo Atriplex prostrata Sporadic species: Calamagrostis epigejos 2 (+), Chaerophyllum bulbosum 2 (+), Fallopia dumetorum 2 (+), Humulus lupulus 2 (1), Polygonum minus 3 (+), Scrophularia nodosa 3 (+), Achillea salicifolia 5 (+), Avena fatua 5 (+), Bidens tripartita 5 (+), Lapsana communis 6 (+), Matricaria maritima subsp. inodora 6 (+), Taraxacum officinale 10 (+), Polygonum mite 12 (+), Polygonum lapathifolium subsp. lapathifolium 16 (+), Ranunculus sceleratus 16 (+), Sonchus asper 16 (+), Thlaspi arvense 16 (+), Bidens frondosa 18 (+), Cyperus fuscus 18 (+), Mentha aquatica 18 (+)

58 58 Renata Afranowicz Typical land variant (Table 23, relevés 1-25) The dominating component of that variant was Phragmites australis, which covered 60-90% of the area. Among more frequent species of the class Phragmitetea were: Carex riparia, Iris pseudacorus, Poa palustris and Phalaris arundinacea. The accompanying species occurred with varied frequency and abundance. Due to the high floristic diversity, three subvariants were distinguished: subvariant with Solanum dulcamara and Lycopus europaeus. It grew in wet sites in the bankside area of mainly large watercourses, especially on Nogat river and Cieplicówka canal (Table 23, relevés 1-5); fertile subvariant, characterized by large participation of nitrophilous plants: Urtica dioica and Cirsium arvense. It developed in the flood zone of canals and drainage ditches as well as small, natural watercourses (Table 23, relevés 6-19); subvariant of Common Reed aggregations, in which the qualitative and quantitative participation of other species was minimal (Table 23, relevés 20-25). Association: Acoretum calami Kobendza 1948 (Table 24, relevés 1-10) The association was represented by phytocoenoses of low, relatively dense Sweet Flag swamp. It belongs to strictly nitrophilous plant communities, resistant to human impact. In the studied area it was noted in natural watercourses as well as in canals and drainage ditches, located close to human settlements, pastures and cattle watering-places. Phytocoenoses were built by dominant Acorus calamus and other swamp species. Among more frequent there were: Glyceria maxima, Lycopus europaeus, Phalaris arundinacea, Lythrum salicaria, Iris pseudacorus and Carex acutiformis. Insome patches located in the bankside area of natural watercourses, pleustophytes such as: Lemna sp. div., Spirodela polyrhiza and Hydrocharis morsus-ranae were noted (Table 24, relevés 6-10). However, their cover didn t exceed 20%. In the utmost cases stands of Acoretum calami were represented by phytocoenoses of the aggregation type, built exclusively by policormons of Acorus calamus. Association: Glycerietum maximae Hueck 1931 (Table 25, relevés 1-25) The Reed Sweetgrass was a very common plant community in the u³awy Wiœlane region. Well developed, dense and floristically rich patches of that association grew in the bankside area of natural and artificial watercourses. In the described phytocoenoses Glyceria maxima was a dominant species and formed small stands, usually not exceeding 10 m. They had shape of narrow strips on the banks of watercourses. The floristical composition of the community consisted of large number of accompanying species (54), varied in abundance and quantity. However, over half of them occurred only once or twice in the studied phytocoenoses.

59 Table 23. Phragmitetum australis typical land variant subvariant with Solanum dulcamara and Lycopus europaeus subvariant with nitrophilous plants subvariant dominated by Phragmites australis Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type ln sn lc d sn sc sn d sc ln d lc d sc d sn d sc sc ln d sc ln sn ln Cover of above water herb layer c/c (%) Relevé area (m ) Number of species Ch. Phragmitetum australis Phragmites australis c, c D. of the variant Calystegia sepium c, c Lythrum salicaria Lysimachia vulgaris Senecio fluviatilis Sporadic species: Solidago gigantea 1 (+), Senecio paludosus 3 (+), Agrostis gigantea 15 (+), Filipendula ulmaria 25 (+) Ch. Phragmition, Phragmitetalia, Phragmitetea Carex acutiformis c, c Iris pseudacorus Sium latifolium

60 Galium palustre Glyceria maxima Typha latifolia Phalaris arundinacea Carex riparia Equisetum fluviatile Acorus calamus Cicuta virosa Rumex hydrolapathum Rorippa amphibia Poa palustris Alisma plantago-aquatica Typha angustifolia Bolboschoenus maritimus Schoenoplectus tabernaemontani Sporadic species: Carex pseudocyperus 2 (1), Carex paniculata 4 (1), Eleocharis palustris 22 (+) Accompanying species: Ch. Alnetea glutinosae Solanum dulcamara c, c Lycopus europaeus Ch., D. Artemisietea vulgaris (Convolvuletalia sepium*) Urtica dioica c, c Cirsium arvense *Symphytum officinale Anthriscus sylvestris

61 Glechoma hederacea Rubus caesius Myosoton aquaticum Carduus crispus Lamium album Artemisia vulgaris Arrhenatherum elatius Sporadic species: Cirsium vulgare 5 (+), Galeopsis pubescens 6 (+) Ch. Molinio-Arrhenatheretea Elymus repens c, c Vicia cracca Myosotis palustris Equisetum palustre Heracleum sibiricum Lathyrus pratensis Geranium pratense Sporadic species: Stachys palustris 1 (+), Caltha palustris 3 (+), Dactylis glomerata 9 (+), Phleum pratense 9 (+), Alopecurus pratensis 15 (+), Deschampsia caespitosa 17 (2), Juncus tenuis 23 (+) Other species: Polygonum amphibium f. terrestre c, c Equisetum arvense Epilobium hirsutum Atriplex prostrata Vicia sepium Sonchus palustris Sporadic species: Epilobium palustre 5 (+), Arctium lappa 6 (+), Sambucus nigra 6 (1), Equisetum pratense 10 (+), Chenopodium polyspermum 11 (+), Galium mollugo 15 (+), Sonchus arvensis 15 (+), Taraxacum officinale 15 (+), Lapsana communis 18 (+), Tanacetum vulgare 18 (+), Polygonum hydropiper 20 (+), Polygonum mite 20 (+), Juncus effusus 23 (+), Bidens frondosa 23 (+), Ranunculus sceleratus 23 (+), Rumex maritimus 23 (+)

62 62 Renata Afranowicz Table 24. Acoretum calami Kobendza 1948 Successive number of relevé Number of relevé in the field Date: day month year Localitynumber (see chapter 2.1) Watercourse type ln d ln d ln sn ln ln ln d Cover of above water herb layer c (%) surface water herb layer c (%) <1 <1 <1 submerged herb layer c! (%) <1-5 <1 <1 Water depth (m) Relevé area (m ) Number of species Ch. Acoretum calami Acorus calamus Ch. Phragmition, Phragmitetalia, Phragmitetea Glyceria maxima c Iris pseudacorus Rorippa amphibia Typha latifolia Carex riparia Rumex hydrolapathum Phalaris arundinacea Carex acutiformis Bolboschoenus maritimus Sporadic species: Butomus umbellatus 1 (+), Carex gracilis 1 (2), Poa palustris 1 (+), Scutellaria galericulata 3 (+), Equisetum fluviatile 4 (1), Galium palustre 4 (+), Typha angustifolia 5 (2), Sium latifolium 6 (+) Accompanying species: Ch. Lemnetea minoris Spirodela polyrhiza c Lemna trisulca c! Lemna minor c Lemna gibba Ch. Potametea Hydrocharis morsus-ranae c Sporadic species: c!: Ceratophyllum demersum 8 (1), Potamogeton sp. 10 (+) Other species: Lycopus europaeus c Lythrum salicaria Myosotis palustris Stachys palustris Equisetum palustre Sporadic species: Bidens cernua 1(+), Bidens tripartita 1(+), Mentha aquatica 1(1), Rumex conglomeratus 1(+), Cirsium arvense 3 (+), Lathyrus pratensis 3 (+), Polygonum amphibium f. terrestre 3 (+), Typha latifolia 3 (+), Vicia cracca 3 (+), Alopecurus geniculatus 4 (+), Eupatorium cannabinum 8 (+), Filipendula ulmaria 8 (+)

63 Table 25. Glycerietum maximae Hueck1931 Successive number of relevé Number of relevé in the field Date: day month year Localitynumber (see chapter 2.1) Watercourse type sn sc sc sc sc ln sn sc d sn sc ln sn d d d sn ln d sn sc sc d d ln Cover of above water herb layer c (%) surface water herb layer c (%) submerged herb layer c! (%) Water depth (m) Relevé area (m ) Number of species Ch. Glycerietum maximae Glyceria maxima c Ch. Phragmition, Phragmitetalia, Phragmitetea Iris pseudacorus c Alisma plantago-aquatica Sium latifolium Phalaris arundinacea Rorippa amphibia Phragmites australis Sparganium erectum Cicuta virosa Rumex hydrolapathum Scutellaria galericulata Carex riparia

64 Acorus calamus Butomus umbellatus Typha latifolia Oenanthe aquatica Sporadic species: Carex gracilis 6 (1), Veronica anagallis-aquatica 11 (+), Sagittaria sagittifolia 13 (+), Galium palustre 19 (+), Carex pseudocyperus 21 (+), Equisetum fluviatile 24 (+) Accompanying species: Ch. Lemnetea minoris Lemna minor c Spirodela polyrhiza Lemna trisulca c! Sporadic species: c : Wolffia arrhiza 1 (+), Lemna gibba 2 (+) Ch. Potametea Hydrocharis morsus-ranae c Ceratophyllum demersum c! Sporadic species: c : Stratiotes aloides 1 (+), Nuphar lutea 25 (+), c!: Potamogeton sp. 1 (+) Other species: Calystegia sepium c Lythrum salicaria Myosotis palustris Bidens cernua Solanum dulcamara Lycopus europaeus Epilobium hirsutum Symphytum officinale Typha latifolia Equisetum palustre Ranunculus repens Sporadic species: Cirsium arvense 1 (+), Polygonum amphibium f. terrestre 5 (+), Bidens tripartita 6 (+), Scirpus sylvaticus 7 (+), Ranunculus sceleratus 11 (+), Stachys palustris 12 (+), Rorippa palustris 16 (+), Epilobium palustre 19 (+), Juncus articulatus 19 (+), Caltha palustris 21 (+), Filipendula ulmaria 21 (+), Valeriana officinalis 25 (+)

65 Vegetation of watercourses and their margins Among frequent components of the community there were: Lemna minor, L. trisulca, Spirodela polyrhiza, Iris pseudacorus, Alisma plantago-aquatica, Sium latifolium, Phalaris arundinacea and Rorippa amphibia. Also dense patches built by lying shoots of Glyceria maxima with insignificant participation of other taxa were noted (Table 25, relevés 5, 10, 14, 15, 17, 20, 23). Such phytocoenoses were connected with small watercourses, mainly artificial ones, characterized by a low water level. Association: Oenantho-Rorippetum Lohm (Table 26, relevés 1-3) Well developed patches built by Fine-leaved Water-dropwort and Great yellow-cress appeared rarely in the studied area. They were noted in natural and artificial watercourses, in the area characterized by low water level, not exceeding 0.4 m and a muddy bottom. One of the characteristic species: Oenanthe aquatica or Rorippa amphibia played dominant role in the structure of phytocoenoses. Accompanying taxa occurred with a very low abundance. Among them there were both aquatic species, such as: Lemna minor, L. trisulca, Ceratophyllum demersum, and Reed swamp species, e.g. Alisma plantago-aquatica, Glyceria maxima (see Table 26). Association: Scirpetum maritimi (Br.-Bl. 1931) R.Tx (Table 26, relevés 4-8) Loose facies of Seaside Bulrush community appeared mainly in natural watercourses: Nogat, Stary Nogat, Martwa Wis³a and Linawka although they were also found in one locality in drainage ditch (Table 26, relevé 7), close to Nowotki village. According to ecological requirements, the association was differentiated into freshwater subassociation, occurring on Martwa Wis³a river (Table 26, relevé 4) and halophilous subassociation, spread much wider on other rivers (Table 26, relevés 5-8). Phytocoenoses were built by one of dominants: Schoenoplectus tabernaemontani or Bolboschoenus maritimus. In some patches there were pleustophytes, which migrated from adjacent aquatic communities (Table 26, relevés 5-6). In certain phytocoenoses the surface water layer was well developed and it contained helophytes, which occurred frequently altogether with species characteristic for the association. The halophilous subassociation, which grew in floodplain zone of Martwa Wis³a, was connected with habitats that remained inundated for a long time. That type of phytocoenoses was distinguished by the presence of such halophytes as: Aster tripolium, Atriplex littoralis and Triglochin maritimum. The observed patches of Scirpetum maritimi formed strips and tussocks covering the area up to 30 m. Those tussocks occurred on the Nogat river as monospecies stands of Soft-Stem Bulrush. Only in one locality in artificial watercourse the community was dominated by Bolboschoenus maritimus, with significant role of Alopecurus aequalis and Equisetum palustre as accompanying species. That patch covered the area of 5 m and occurred in shallow water, not exceeding 0.2 m.

66 66 Renata Afranowicz Table 26. Oenantho-Rorippetum Lohm (relevés 1-3) and Scirpetum maritimi (Br.-Bl. 1931) R.Tx (relevés 4-8) Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type d sc sc ln ln ln d ln Cover of above water herb layer c (%) surface water herb layer c (%) submerged herb layer c! (%) Water depth (m) < Relevé area (m ) Number of species Ch. Oenantho-Rorippetum Rorippa amphibia c Oenanthe aquatica Ch. Scirpetum maritimi Schoenoplectus tabernaemontani c Bolboschoenus maritimus Ch. Phragmition, Phragmitetalia, Phragmitetea Phragmites australis c Sagittaria sagittifolia Glyceria maxima Alisma plantago-aquatica Sporadic species: Veronica anagallis-aquatica 2 (+), Rumex hydrolapathum 3 (+), Eleocharis palustris 4 (+), Sparganium emersum 5(+), Schoenoplectus lacustris 7 (+), Typha latifolia 7 (+), Acorus calamus 8 (+), Phalaris arundinacea 8 (+) Accompanying species: Ch. Lemnetea minoris Lemna minor c Lemna trisulca c! Spirodela polyrhiza c Sporadic species: c : Salvinia natans 6 (1) Ch. Potametea Ceratophyllum demersum c! Hydrocharis morsus-ranae c Nuphar lutea c Sporadic species: c : Nymphaea alba 5(+), c!: Elodea canadensis 3 (+) Other species: Equisetum palustre c Agrostis stolonifera Sporadic species: Myosotis palustris 1(+), Bidens tripartita 2(+),Lycopus europaeus 3(+), Aster tripolium 4(+), Atriplex littoralis 4(+), Scirpus sylvaticus 4(2),Triglochin maritimum 4(+), Alopecurus aequalis 7(1),Rorippa sylvestris 7 (+), Calystegia sepium 8(+), Rorippa palustris 8 (+)

67 Vegetation of watercourses and their margins Association: Caricetum ripariae Soó 1928 (Table 27, relevés 1-5) The Great Pond Sedge swamp was one of the most widespread communities of the alliance Magnocaricion in the u³awy Wiœlane region and grew on the banks of both natural and artificial watercourses. Typically developed patches were rather rare in the studied area. More frequent were small phytocoenoses formed by aggregations of Carex riparia. They were mainly located on the seasonally flooded banks of natural watercourses, adjacent to phytocoenoses of Phragmitetum australis, Acoretum calami or Glycerietum maximae. Typical phytocoenoses were dominated by Carex riparia. It was accompanied by characteristic species of the class Phragmitetea as well as other plants of aquatic and swamp habitats. Among frequently noted species there were: Glyceria maxima, Iris pseudacorus, Solanum dulcamara, Lythrum salicaria, Calystegia sepium and Lysimachia vulgaris. Cover of the emerged herb layer was from 90 to 95%. Association: Caricetum acutiformis Sauer 1937 (Table 27, relevés 6-7) The Lesser Pond Sedge swamp appeared in localities scattered in the studied area. The community was represented by phytocoenoses forming narrow strips mostly along small artificial and natural watercourses. In the small-area phytocoenoses Carex acutiformis was a dominant. It grew massively and formed floristically very poor communities. Other species, like: Phalaris arundinacea or Lythrum salicaria, appeared sporadically. Total cover of herbs in particular patches was on average 80%. Association: Caricetum gracilis (Graebn. et Hueck 1931) R.Tx (Table 27, relevés 8-9) That association contained large sedge phytocoenoses with a dominant role of Slender Tufted-sedge. They were rarely observed on the banks of watercourses. In the small area phytocoenoses Carex gracilis had usually about 80% of cover, however, other species connected with wet habitats were relatively frequent. Among them the most abundant were: Phalaris arundinacea, Rumex hydolapathum and Solanum dulcamara (see Table 27, relevés 8, 9). Association: Thelypteridi-Phragmitetum Kuiper 1957 (Table 27, relevé 10) This was a swamp community of Marsh fern and Common Reed, which had a specific two-layer physiognomy. In u³awy Wiœlane that association occurred in the quite large flood plain of Fiszewka river, south of Jeg³ownik village. The community grew on marshy soils, which were seasonally flooded. The water level didn t exceed 0.2 m. The only patch noted within the studied area covered about 80 m and was characterized by weakly developed hummock-hollow complex. In that phytocoenosis Thelypteris palustris was a dominant species and Typha latifolia occurred as a subdominant. In the hollows filled up with water Lemna minor was

68 68 Renata Afranowicz observed. Among other species there were: Carex pseudocyperus, C. riparia, Lythrum salicaria and Rumex hydrolapathum (see Table 27, relevé 10). Table 27. Caricetum ripariae Soó 1928 (relevés 1-5), Caricetum acutiformis Sauer 1937 (relevés 6-7) Caricetum gracilis (Graebn. et Hueck 1931) R.Tx (relevés 8-9), Thelypteridi- Phragmitetum Kuiper 1957 (relevé 10), Iridetum pseudacori Eggler 1933 (relevé 11) and Phalaridetum arundinaceae (Koch 1926 n.n.) Lib (relevés 12) Successive number of relevé Number of relevé in the field Date: day month year Locality number (see chapter 2.1) Watercourse type ln d sn sn sn sc d sn ln ln d d Cover of above water herb layer c (%) surface water herb layer c (%) submerged herb layer c! (%) Water depth (m) Relevé area (m ) Number of species Ch. Caricetum ripariae Carex riparia c Ch. Caricetum acutiformis Carex acutiformis c Ch. Caricetum gracilis Carex gracilis c Ch. Thelypteridi-Phragmitetum Thelypteris palustris c Ch. Iridetum pseudacori Iris pseudacorus c Ch. Phalaridetum arundinaceae Phalaris arundinacea c Ch. Magnocaricion, Phragmitetalia, Phragmitetea Galium palustre c Rumex hydrolapathum Glyceria maxima Typha latifolia Iris pseudacorus Sium latifolium Sparganium erectum Phragmites australis Carex paniculata Sporadic species: Cicuta virosa 3 (+), Carex pseudocyperus 10 (1), Alisma plantago-aquatica 11 (+), Equisetum fluviatile 11 (1), Carex acutiformis 12 (2)

69 Vegetation of watercourses and their margins Other species: Lythrum salicaria c Solanum dulcamara Lycopus europaeus Lemna minor c Calystegia sepium c Symphytum officinale Lysimachia vulgaris Myosotis palustris c Lemna trisulca c! Spirodela polyrhiza c Sporadic species: c:bidens tripartita 3 (+), Agrostis gigantea 4 (+), Mentha longifolia 9 (+), Filipendula ulmaria 10 (+), Epilobium hirsutum 11 (+), Alopecurus pratensis 12 (+), Carduus crispus 12 (+), Thalictrum aquilegiifolium 12 (+), Urtica dioica 12 (+) Association: Iridetum pseudacori Eggler 1933 (Table 27, relevé 11) The Paleyellow Iris community was represented by the small-area phytocoenoses. In the studied area small patches of that community occurred rarely. They were noted in roadside ditches as well as in small drainage canal. The phytocoenoses had a two-layer structure. Iris pseudacorus was a dominant species and it covered usually ca. 80% of the area. Paleyellow Iris was accompanied by relatively high number of varied species, including species of the class Phragmitetea and others from wet habitats. The only surface water plant was Lemna minor, which covered up to 30% of the area (see Table 27, relevé 11). Iris pseudacorus was one of common components of the flora of u³awy Wiœlane and it appeared very often also in other Reed swamp communities. Association: Phalaridetum arundinaceae (Koch 1926 n.n.) Lib (Table 27, relevé 12) This is a community of tall grasses of the alliance Magnocaricion, built by Reed Canarygrass. Well developed patches of that association were rare and scattered over the whole u³awy Wiœlane region. They occurred in the flood zone of drainage ditches and canals as well as along the large natural watercourses. Phytocoenoses dominated by Phalaris arundinacea were floristically poor (see Table 27, relevé 12). The most common accompanying species were: Carex acutiformis and Symphytum officinale. Phalaris arundinacea was a common plant species that occurred also in varied Reed swamp communities of the studied area.

70 70 Renata Afranowicz 3.2. Correlations between vegetation and chosen features of watercourse and human impact Commonness of plant communities Diversity of vegetation connected with natural and artificial watercourses reveals in frequency of occurrence of particular communities. Among the total number of 34 identified plant associations (including 20 aquatic communities and 14 Reed swamps), 11 occurred in all four types of watercourses (Table 28). Among them were aquatic communities, like: Lemno minoris-salvinietum natantis, Spirodeletum polyrhizae, Lemnetum gibbae, Ceratophylletum demersi and Hydrocharitetum morsus-ranae, as well as Reed swamps, such as: Phragmitetum australis, Acoretum calami and Glycerietum maximae. Phytocoenoses representing those plant associations occurred in the studied area most frequently and comprised almost 70% Table 28. Frequency of particular plant communities in different types of watercourses (the total number of notations for aquatic N=255, and for Reed swamps N=232) Community type AQUATIC COMMUNITIES Plant association no. of notations NOTATIONS IN WATERCOURSES NATURAL ARTIFICIAL large small large small %of total no. of notations %of total no. of notations %of total no. of notations %of total Spirodeletum polyrhizae Lemnetum gibbae Wolffietum arrhizae Ricciocarpetum natantis Lemnetum trisulcae Lemno minoris- -Salvinietum natantis Elodeetum canadensis Ceratophylletum demersi Myriophylletum spicati Ranunculetum circinati Potametum pectinati Potametum lucentis Potametum friesi Potametum natantis Polygonetum natantis Nymphoidetum peltatae Myriophylletum verticillati Hydrocharitetum morsus-ranae Nupharo-Nymphaeetum albae Hottonietum palustris SUM

71 Vegetation of watercourses and their margins REED SWAMP COMMUNITIES Sparganietum erecti Typhetum angustifoliae Typhetum latifoliae Phragmitetum australis Acoretum calami Glycerietum maximae Oenantho-Rorippetum Scirpetum maritimi Caricetum ripariae Caricetum acutiformis Caricetum gracilis Thelypteridi-Phragmitetum Iridetum pseudacori Phalaridetum arundinaceae SUM of all notations (Table 29, Fig. 4). The other group was formed by plant associations found in large and small natural watercourses and small artificial ones (Table 29, Fig. 4). The group included pleustophyte communities, such as: Lemnetum trisulcae, L. gibbae and Wolffietum arrhizae and Reed swamps: Typhetum latifoliae and Caricetum ripariae. Moreover, the most abundant were phytocoenoses of Lemnetum trisulcae and Typhetum latifoliae, which occurred most often in small watercourses (see Table 28). Table 29. Frequency of groups of aquatic and Reed swamp plant communities in particular types of watercourses Watercourse type Aquatic communities no. of notations %ofsum [N=255] Reed swamp communities no. of notations %ofsum [N=232] % of total [N=487] all ln, la, sa ln, sn, sa sn, la, sa ln, sn ln, sa la, sa sn, sa la sa Explanations: ln large natural watercourse, la large artificial, sn small natural, sa small artificial Several plant communities, demanding specific habitat conditions, in the studied area were noted rarely and only in certain types of watercourses (see Table 28). Among them there were aquatic phytocoenoses, found only in small

72 72 Renata Afranowicz Fig. 4. Distribution of notations number of groups of aquatic and Reed swamp communities in particular watercourse types (abbreviations as in Table 29). natural and artificial watercourses: Ricciocarpetum natantis, Potametum pectinati, P. friesi and Hottonietum palustris. Patches of Thelypteridi-Phragmitetum were in turn observed only in natural watercourses, while Potametum natantis and Iridetum pseudacori occurred only in artificial watercourses (see Table 28). Some plant communities were connected with the only one watercourse type. Phytocoenoses of Ranunculetum circinati, Nymphoidetum peltatae and Typhetum angustifoliae were visibly associated with large rivers, while patches of Polygonetum natantis, Oenantho-Rorippetum, Caricetum acutiformis and Phalaridetum arundinaceae were observed only in small artificial watercourses (see Table 28) Phytocoenotical diversity versus watercourse size and origin Diversity of aquatic communities in relation to the width and type of watercourse, which is connected with its origin and degree of human impact, was analyzed using DCA method (Fig. 5). The first and second axes altogether explained ca. 30% of the floristic diversity. Differentiation along the first axis was associated with variability of species composition, while values of reaction (R), nitrogen (N) and salinity (S) indexes were correlated with the second axis. Communities of Wolffietum arrhizae, Lemnetum gibbae and Elodeetum canadensis were grouped in the range of the highest values of Ellenberg s indexes, while Nupharo-Nymphaeetum albae was visibly connected with the lowest values of those indicators.

73 Vegetation of watercourses and their margins The diversity of aquatic vegetation, observed along the second axis in the gradient of habitat fertility and salinity degree is connected with watercourse type and morphometry. The large-area patches of Nupharo-Nymphaeetum albae and Lemno minoris-salvinietum natantis are associated with large natural and artificial watercourses. And communities: Wolffietum arrhizae, Lemnetum gibbae and Elodeetum canadensis have their optimum of occurrence in small rivers and canals. Phytocoenoses of Lemnetum trisulcae, Spirodeletum polyrhizae and Ceratophylletum demersi grow in turn most often in drainage ditches. The observed large spread of relevés with Hydrocharis morsus-ranae along the first axis is a result of higher diversity of species composition than in case of other plant associations. On the Fig. 5 relevés representing patches with Hydrocharis morsusranae in the variant with Stratiotes aloides are separated from the typical variant and they are enclosed within an ellipse. Explanations: watercourse type: d ditches, lc large canals, ln large natural watercourses, sc small canals, sn small natural watercourses; mean values of Ellenberg s indicators of: N nitrogen, S salinity, R reaction Fig. 5. Diversity of aquatic plant communities according to watercourse type and size (DCA ordination diagram)

74 74 Renata Afranowicz Relevés representing Reed swamp communities growing on watercourses of varied morphometry were also analyzed using the DCA method. Its result is displayed in Figure 6. The relevés are sorted along the second axis, which explains 17% of the diversity. The gradient of reaction is the most significant factor connected with that axis, and the other ones are: nitrogen and salinity. In the range of highest values of R, N and S indicators there is a group of relevés representing Typhetum angustifoliae and Scirpetum maritimi. The evident division of the Sweet Flag community into two groups results from different habitat conditions, mostly content of sodium chloride as well as from domination in phytocoenoses one of the two species that are characteristic for that plant association (see Chapter 3.1.2). The rest of phytocoenoses doesn t show significant diversity along the given gradients. Explanations: watercourse type: d ditches, lc large canals, ln large natural watercourses, sc small canals, sn small natural watercourses; mean values of Ellenberg s indicators of: N nitrogen, S salinity, R reaction Fig. 6. Diversity of Reed swamp communities according to watercourse type (DCA ordination diagram)

75 Vegetation of watercourses and their margins Phytocoenotical differentiation according to watercourse type and width is most noticeable in case of large rivers of u³awy Wiœlane. Along their banks there are concentrations of patches of Typhetum angustifoliae and some patches of Scirpetum maritimi. Other Reed swamps express tendency to concentrate on natural large and small watercourses or artificial ones drainage ditches and canals Spatial diversity of plant communities in particular types of watercourses The executed observations and analyses point that different spatial configurations of aquatic and Reed swamp vegetation appear in relation to the origin and width of watercourses (Fig. 7). Small rivers and canals were often covered by dense phytocoenoses with Lemna minor, L. gibba, Spirodela polyrhiza, Hydrocharis morsus-ranae and Ceratophyllum demersum within the submerged layer. Banks of those watercourses were overgrown by narrow strips of Reed swamps: Phragmitetum australis, Glycerietum maximae or Caricetum ripariae (Fig. 7A). The particularly characteristic feature of the u³awy Wiœlane landscape is a dense network of drainage ditches. The narrow beds and banks of those ditches were most frequently covered by stands of Phragmitetum australis or Typhetum latifoliae (Fig. 7B1). Sometimes they occurred only in marginal zone, while central part of watercourse was covered by mats of Spirodeletum polyrhizae, Hydrocharitetum morsus-ranae, Lemnetum trisulcae or Elodeetum canadensis (see Fig. 7B2). Large and medium size rivers, as well as large canals that are similar to them, had complete different physiognomy. The major component of their vegetation was Nupharo-Nymphaeetum albae, which large-area patches often covered considerable area of the water surface. Toward the banks, the area was quite often occupied by patches of Lemno minoris-salvinietum natantis, visible only in the second half of summer, and in the submerged water layer there were mats of Potametum lucentis. Phytocoenoses of Typhetum angustifoliae, and frequently also aggregations of Scirpetum maritimi with Schoenoplectus tabernaemontani as well as hummocks or small groups of Butomus umbellatus, occurred in the contact zone of aquatic and Reed swamp communities, but only along large rivers, such as: Nogat, Szkarpawa, Tina and Tuga. The wide strips of Common Reed swamps Phragmitetum australis, were observed in both natural and artificial, large watercourses and it was stretched from the floodplain to the bankside area (Fig. 7C).

76 76 Renata Afranowicz A natural, small watercourses with swamp communities of: Common Reed (A1), Reed Sweetgrass (A2a) and sedges (A2b), B artificial, small watercourses with swamp communities of Common Reed (B1a), Common Cattail (B1b) and Reed Sweetgrass (B2), C natural, large watercourses (Ca) and large canals (Cb); 1 Phragmites australis, 2 Typha latifolia, 3 Typha angustifolia, 4 Glyceria maxima, 5 Carex spp., 6 Hydrocharis morsus-ranae, 7 Lemna minor, 8 Salvinia natans, 9 Ceratophyllum demersum, 10 Elodea canadensis, 11 Potamogeton lucens, 12 Nuphar lutea and Nymphaea alba Fig. 7. Sections of particular watercourse types and schemes of composition of aquatic and Reed swamp communities (drawn by T. S. Olszewski)

77 Vegetation of watercourses and their margins Discussion Watercourse vegetation is one of significant components of the u³awy Wiœlane landscape, mainly due to its areal participation, frequency of occurrence and being a part of varied spatial arrangements. Among widely distributed communities of the studied area, occurring in both natural and artificial watercourses of different morphometry, there are phytocoenoses of aquatic plant associations: Spirodeletum polyrhizae, Lemnetum trisulcae, Elodeetum canadensis, Hydrocharitetum morsus-ranae and Ceratophylletum demersi, as well as Reed swamps, such as: Phragmitetum australis, Glycerietum maximae, Sparganietum erecti and Typhetum latifoliae. Those plant communities are common on the country scale. They are characterized by the wide ecological amplitude and were noted also in peat excavation hallows, oxbow lakes, fishing ponds, astatic ponds or lakes (see Tomaszewicz 1979; K³osowski 1992; Podbielkowski, Tomaszewicz 1996; K³osowski, Tomaszewicz 1997; Wo³ek 1997; Matuszkiewicz 2005). One of the particularly interesting plant communities in the u³awy Wiœlane region is Nymphoidetum peltatae, which uncommon localities are scattered over the area of Poland (Kordakow 1969; Tomaszewicz 1979). Well developed, largearea patches of that community occurring at Druzno Lake have been known for a long time and were described many times in the literature (Schulz 1941; Lenczewski 1955, 1957; Kluszczyñska, Szmeja 1979; Buliñski 1998; K³osowski 2001; Markowski et al. 2002). Two other localities of that association were reported from the u³awy Wiœlane region (Œroda 1991a) and they were located in large natural watercourse, similarly as the new one, found during the author s field research. Also in the literature there is information about occurrence of Nymphoidetum peltatae in very fertile waters of such watercourses (see Smits et al. 1988; K³osowski, Tomaszewicz 1996). Wolffietum arrhizae is another rare component of vegetation of the u³awy Wiœlane region. This is a plant association not included in generally accepted in Poland syntaxonomical system by Matuszkiewicz (2005), although it was identified by many authors (see Olaczek, Krzywañski 1970; Krzywañska, Krzywañski 1972; Tomaszewicz 1977; Samosiej, Kucharski 1986; Podbielkowski, Tomaszewicz 1996). In u³awy Wiœlane, similarly to other regions, phytocoenoses of that association were observed in fertile, sheltered from the wind and quickly warming waters, but only in small natural or artificial watercourses. As the habitat conditions and structure of the patches were comparable to phytocoenoses described by the authors mentioned above, in present work they were also distinguished as a separate plant association. It is worth to mention that classification of Wolffietum arrhizae and Lemnetum gibbae as independent syntaxonomical units, according to separate occurrence of their characteristic species (see Olaczek, Krzywañski 1970; Krzywañski 1974), seems to be confirmed by phytocoenoses observed in the studied area (see Table 3, relevés 1-14).

78 78 Renata Afranowicz Phytocoenoses of Ricciocarpetum natantis are also connected with small watercourses of the Wis³a river delta. Opposite to information from other regions, where they occur in gaps among aquatic and swamp plants (see Krzywañski 1974; K³osowski et al. 1999), in u³awy Wiœlane phytocoenoses of Ricciocarpetum natantis cover the whole width of watercourses. Moreover, they were found in drainage ditch, while in literature that plant association was reported from lakes, astatic ponds, peat excavation hallows and oxbow lakes (HereŸniak 1972; Tomaszewicz 1979; Pe³echaty, G¹bka 2003). During the field research in the u³awy region a wide spread and massive occurrence of Salvinia natans were observed and the species formed large-area phytocoenoses of Lemno minoris-salvinietum natantis. They were found in both natural and artificial watercourses, while from other parts of the country they were reported mostly from lakes, oxbow lakes or fishing ponds (Tomaszewicz 1979; Michalska-Hejduk, Kopeæ 2002; Markowski et al. 2004; Spa³ek 2006). Stands of Typhetum angustifoliae, opposite to the widely distributed patches of Common Cattail association, are associated with larger reservoirs of running waters. They prefer waters significantly deeper than those, in which Typhetum latifoliae occurs (see Toivonen, Bäck 1989; Toivonen, Nybom 1989). The mutual exclusion of those two Typha species was observed also by Tomaszewicz (1973) and Krzywañski (1974). The wide spread of the Common Reed community in the u³awy Wiœlane area is associated with high expansiveness of Phragmites australis (see Barrett et al. 1993; Ennabili et al. 1998; Brix, ÈR ková 2001; Boszke et al. 2005). Due to varied species composition, phytocoenosis structure and habitat diversity, the Common Reed community was divided into few variants, which are especially frequent and well developed along the large rivers. Such division seems to be reasonable, taking into account former suggestions presented in the literature. Tomaszewicz (1979) mentioned that the community dominated by Phragmites australis is treated too wide and without consideration its internal diversity. Floristically poorest variant of the Phragmitetum australias the one with aquatic species, grows in the bankside zone of watercourses, where water is always present (see Table 17). Along with decreasing hydration degree of the bankside zone as well as with the time and frequency of flooding, different variants of the Reed swamp community occur and they are characterized by certain floristic composition. Phytocoenoses of the Common Reed swamps with tall herbs, often with significant participation of nitrophytes, are floristically rich, alike Reed swamp with Calystegia sepium, which grows in the bankside of large natural and artificial watercourses. High diversity of Phragmites australis association was also noted in the Bay of Elbl¹g and Druzno Lake (see Szmeja 1998; Markowski et al. 2002). No significant diversity was in turn observed along small watercourses, as mostly mono-species aggregations of Common Reed or phytocoenoses with large share of grasses, especially Agrostis gigantea and A. stolonifera, occurred in those places. The halophilous variant of Phragmitetum australis (see Table 18) was clearly distinguished and its occurrence was limited to saline

79 Vegetation of watercourses and their margins habitats of Martwa Wis³a floodplain. The spread of Common Reed, observed in that area, is connected with discontinuance of grazing and mowing, which results in disappearance of halophytes and degradation of their communities (see Piotrowska 1974; Bartoszuk 2003). Width of watercourse is an important factor influencing distribution of species, and in consequence their communities, not only in the Wis³a river delta. Significance of that factor was pointed also in researches abroad (see Bornette, Amoros 1991; Khedr, El-Demerdash 1997; Riis et al. 2000). This is associated with different water conditions, such as: smaller depth and smaller water flow as well as more intense anthropogenic impact in small watercourses comparing to the large ones. Habitat gradients, interpreted with DCA method, confirm descriptions of habitat requirements of particular plant communities (see e.g. Tomaszewicz 1979; Podbielkowski, Tomaszewicz 1996). High similarity of floristic composition of the analyzed communities was supported by Detrended Correspondence Analysis. There was a tendency to group samples (represented by relevés), according to visibly similar species composition of particular plant communities growing along natural ad artificial watercourses, which varied in size. Watercourse type and morphometry were significant in case of some communities, showing clear preference to particular category of watercourse (see chapter 3.2.1). General trends in distribution of plant communities due to the origin and morphometry of watercourses, established with the use of multivariate method DCA (see Fig. 6), confirmed results of classic analysis of phytosociological data. Habitats connected with watercourses, especially those within floodplain area and bankside zone, are often being disturbed. The smallest watercourses are strongly influenced by farming activities on adjacent fields and pastures. Moreover, smaller canals and drainage ditches are more often maintained. Those techniques have an influence on watercourse flora and vegetation (see Podbielkowski 1967; Wade, Edwards 1980; de Mars et al. 1996; Sabbatini et al. 1998). However, even in such disturbed watercourses some phytocoenoses, like Elodeetum canadensis or Sparganietum erecti, remain (Go³dyn 1984). Places that have been desludged or grubbed usually have no vegetation cover and they are being colonized mainly by invasive and strongly competing species. The important roles in the overgrowing process play aquatic species, such as: Lemna minor, L. trisulca, Spirodela polyrhiza, Hydrocharis morsus-ranae, Ceratophyllum demersum, Elodea canadensis, Nuphar lutea and among the Reed swamp ones: Typha latifolia, Glyceria maxima and Phragmites australis (see Podbielkowski 1960, 1967; Æwiertnia 1962; van der Putten 1997; Lenssen et al. 1999). In artificial watercourses the overgrowing process is frequently disturbed by cleaning, which disables forming successionally advanced plant communities (see Podbielkowski 1967; Krzywañska, Krzywañski 1972; Œroda 2000a, b, c). Phytocoenoses of macrophytes develop in drainage ditches when the stream management is minimalized (Pedersen et al. 2006). In case of small natural watercourses, the shallowing and overgrowing by phytocoenoses dominated by Stratiotes aloides were in turn

80 80 Renata Afranowicz observed. Similar patches were noted also in artificial watercourses, which hadn t been maintained for few years, e.g. the Wiœlano-Zalewowy canal. Watercourses and their margins in the Wis³a river delta play role as refuges and ecological corridors in the agricultural landscape, which is often dominated by anthropogenic phytocoenoses, such as: cultivated fields, mown meadows or pastures. Also in other regions and countries watercourses play similar role (e.g. Boutin et al. 2003; Lee et al. 2004; Dajdok, Wuczyñski 2005; Kuhar et al. 2007). 5. Conclusions Vegetation of artificial watercourses (canals and drainage ditches), which are the main element of hydrographic network of the u³awy Wiœlane region, shows considerable similarity to vegetation of natural watercourses. The half of all plant communities observed in the studied area is connected with both natural and artificial watercourses and doesn t express clear preference to their size. Moreover, patches of those plant associations are the most frequently observed. Watercourse type and morphometry have in turn an effect on distribution of community types and size of the area covered by them. The intense human impact, especially maintenance of canals and drainage ditches, causes disturbance of vegetation and habitats. Newly uncovered places are often being overgrown by expansive plant species. The results of the research suggest that in the u³awy Wiœlane region the drainage ditches and canals in great extent overtook the function of former natural river beds and oxbow lakes and nowadays play an important role as refuges of floristic and phytocoenotic diversity in the anthropogenic landscape of the Wis³a river delta. Acknowledgements I would like to express my gratitude to persons, who helped me at many stages of preparation of this work: my colleagues dr. Joanna Bloch-Or³owska, dr. Katarzyna ó³koœ, dr. Ryszard Markowski and dr. Tomasz S. Olszewski. I also thank to prof. Jacek Herbich for his promoter role. And special acknowledgements I give to my nearest Family for their priceless support and help.

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83 Vegetation of watercourses and their margins KUHAR U., GREGORC T., RENÈELJ M., ŠRAJ-KRŽIÈ N., GABERŠÈIK A Distribution of macrophytes and condition of the physical environment of streams flowing through agricultural landscape in north-eastern Slovenia. Limnologica 37: KWIECIEÑ K G³ówne cechy klimatu. W: AUGUSTOWSKI B. (red.), Dolina Dolnej Wis³y. GTN, Wydzia³ V Nauk o Ziemi, Zak³. Narod. im. Ossoliñskich, Wyd. PAN, Wroc³aw, s LEE P., SMYTH CH., BOUTIN S Quantitative review of riparian buffer width guidelines from Canada and the United States. J. Environ. Manage. 70(2): LENCZEWSKI J Uwagi o roœlinnoœci jeziora Dru no. Ekol. Pol., Ser. A, 3(1): LENCZEWSKI J Niektóre roœliny kwiatowe zbiornika wodnego Druzno. Ekol. Pol., Ser. A, 5(4): LENSSEN J. P. M., MENTING F. B. J., VAN DER PUTTEN W. H., BLOM C. W. P. M Effects of sediment type and water level on biomass production of wetland plant species. Aquat. Bot. 64(2): LEPŠ J., ŠMILAUER P Multivariate analysis of ecological data. Course materials. Faculty of Biological Sciences, University of South Bohemia, Èeské Budìjovice, 242 ss. OMNICKI A Wprowadzenie do statystyki dla przyrodników. PWN, Warszawa, 263 ss. MAJEWSKI A Rozwój hydrograficzny delty Wis³y w okresie historycznym. Przeg. Geofiz. 14(1): MARKOWSKI R., BULIÑSKI M Gin¹ce i zagro one roœliny naczyniowe Pomorza Gdañskiego (Endangered and threatend vascular plants of Gdañskie Pomerania). Acta Bot. Cassub., Monogr. 1: MARKOWSKI R., BULIÑSKI M., S GIN P (mscr.). Opracowanie flory naczyniowej i zbiorowisk roœlinnych faunistycznego rezerwatu przyrody Jezioro Dru no". Zró nicowanie, stan zachowania i zagadnienia ochrony. W: Materia³y do planu ochrony rezerwatu przyrody Jezioro Dru no". Gdañsk. MARKOWSKI R., Ó KOŒ K., BLOCH-OR OWSKA J Salvinia natans (L.) All. na Pomorzu Gdañskim (Salvinia natans (L.) All. in Gdañskie Pomerania). Acta Bot. Cassub. 4: MATUSIK M., SZCZÊSNY R Rolnictwo (Agriculture). W: AUGUSTOWSKI B. (red.), u³awy Wiœlane. GTN, Wydzia³ V Nauk o Ziemi, Gdañsk, s MATUSZKIEWICZ W Przewodnik do oznaczania zbiorowisk roœlinnych Polski. W: FALIÑSKI J. B. (red.), Vademecum Geobotanicum. 3: PWN, Warszawa. MICHALSKA-HEJDUK D., KOPEÆ D Lemno minoris-salvinietum natantis i Hydrocharitetum morsus-ranae z udzia³em Salvinia natans w starorzeczach Sanu i propozycje ich ochrony. Fragm. Flor. Geobot. Polonica 9: MIREK Z., PIÊKOŒ-MIRKOWA H., ZAJ C A., ZAJ C M Flowering plants and pteridophytes of Poland. A checklist. W: MIREK Z. (red.), Biodiversity of Poland. 1: W. Szafer Institute of Botany, Polish Academy of Sciences, Kraków. MIYAWAKI A., TÜXEN J Über Lemnetea Gesellschaften in Europa und Japan. Mitt. D. Flor.-Soziol. Arbeitsgem., N.F. 8: OLACZEK R., KRZYWAÑSKI D Wolffia arrhiza i Wolffietum arrhizae w Polsce. Zesz. Nauk. U, Nauki Mat.-Przyr., ser. II, 36: PAW OWSKI B Sk³ad i budowa zbiorowisk roœlinnych oraz metody ich badania. W: SZAFER W., ZARZYCKI K. (red.), Szata roœlinna Polski. 1: Wyd. 3. PWN, Warszawa. PE ECHATY M., G BKA M Stanowisko Ricciocarpos natans (Ricciaceae, Hepaticopsida) na terenie Wielkopolskiego Parku Narodowego. Fragm. Flor. Geobot. Polonica 10: PEDERSEN T. CH. M., BAATTRUP-PEDERSEN A., MADSEN T. V Effects of stream restoration and management on plant communities in lowland streams. Aquat. Bot. 51(1): PIOTROWSKA H Nadmorskie zespo³y solniskowe w Polsce i problemy ich ochrony. Ochr. Przyr. 39: PODBIELKOWSKI Z Zarastanie do³ów potorfowych. Monogr. Bot. 10(1): PODBIELKOWSKI Z Zarastanie rowów melioracyjnych na torfowiskach okolic Warszawy. Monogr. Bot. 23(1): PODBIELKOWSKI Z., PODBIELKOWSKA M Przystosowania roœlin do œrodowiska. WSiP, Warszawa, 584 ss. PODBIELKOWSKI Z., TOMASZEWICZ H Zarys hydrobotaniki. PWN, Warszawa, 531 ss.

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85 Vegetation of watercourses and their margins TER BRAAK C. J. F., ŠMILAUER P Reference Manual and User s Guide to Canoco for Windows: Software for Canonical Community Ordination (version 4.5). Microcomputer Power (Ithaca, NY, USA). 499 ss. TOIVONEN H., BÄCK S Changes in aquatic vegetation of a small eutrophicated and lowered lake (southern Finland). Ann. Bot. Fenn. 26(1): TOIVONEN H., NYBOM C Aquatic vegetation and its recent succession in the waterfowl wetland Koijärvi, S. Finland. Ann. Bot. Fenn. 26(1): TOMASZEWICZ H Stanowisko systematyczne Scirpo-Phragmitetum W. Koch Acta Soc. Bot. Pol. 42(3): TOMASZEWICZ H Roœlinnoœæ wodno-bagienna w akwenach zlewni Skrwy i Ciechomickiej na Pojezierzu Gostyniñskim. Monogr. Bot. 52: TOMASZEWICZ H Roœlinnoœæ wodna i szuwarowa Polski (klasy: Lemnetea, Charetea, Potamogetonetea, Phragmitetea) wg stanu zbadania na rok Rozpr. UW 160: VAN DER PUTTEN W. H Die-back of Phragmites australis in European wetlands: an overview of the European Research Programme on Reed Die-Back and Progression ( ). Aquat. Bot. 59(3-4): WADE P. M., EDWARDS R. W The effect of channel maintenance on the aquatic macrophytes of the drainage channels of the Monmouthshire Levels, South Wales. Aquat. Bot. 8(4): WO EK J Species co-occurence patterns in pleustonic plant communities (class Lemnetea): are there assembly rules governing pleustonic community assembly? Fragm. Flor. Geobot., Suppl. 5: ZAJ C A Za³o enia metodyczne Atlasu rozmieszczenia roœlin naczyniowych w Polsce. Wiad. Bot. 22(3): ZARZYCKI K., TRZCIÑSKA-TACIK H., RÓ AÑSKI W., SZEL G Z., WO EK J., KORZENIAK U Ecological indicator values of vascular plants of Poland. W: MIREK Z. (red.), Biodiversity of Poland. 2: W. Szafer Institute of Botany, Polish Academy of Sciences, Kraków. u³awy Wiœlane mapa turystyczno-krajoznawcza skala 1:

86 86 Renata Afranowicz Streszczenie Wprowadzenie Delta Wis³y jest obszarem odznaczaj¹cym siê w skali kraju wybitn¹ odrêbnoœci¹ pod wzglêdem historii i dziedzictwa kulturowego krajobrazu, a tak e œrodowiska przyrodniczego. Jej osobliwoœæ wynika ze swoistej genezy, kszta³tuj¹cej specyficzne warunki siedliskowe. Zapocz¹tkowany oko³o 7 tysiêcy lat temu rozwój delty Wis³y podlega³ dynamicznym procesom geologicznym, geomorfologicznym, hydrologicznym oraz antropogenicznym. Ich stopieñ nasilenia i czas trwania mia³y ogromny wp³yw na rozwój i przeobra enia szaty roœlinnej u³aw Wiœlanych. W okresie kilku ostatnich wieków szczególnie istotne by³y oddzia³ywania cz³owieka, stopniowo nasilaj¹ce siê ju od koñca XIII wieku. Obejmowa³y one g³ównie odlesienia, tworzenie bogatej sieci sztucznych cieków, tj. kana³ów i rowów melioracyjnych oraz budowanie wa³ów przeciwpowodziowych. Wraz z osiedlaniem siê cz³owieka coraz wiêksze powierzchnie bardzo yznych mad u³awskich oraz gleb organicznych by³y osuszane i brane pod uprawê. Celem pracy by³a charakterystyka oraz porównanie roœlinnoœci cieków o ró - nej genezie i morfometrii, prowadz¹ce do okreœlenia roli sztucznych cieków jako ewentualnych ostoi naturalnej roœlinnoœci w antropogenicznym krajobrazie delty Wis³y. Teren badañ Badania przeprowadzono na terenie u³aw Wiœlanych, które obejmuj¹ aluwialn¹ równinê o powierzchni oko³o km (Kondracki 2002). W regionalizacji fizyczno-geograficznej Polski (Kondracki 2002), obszar ten wyró nia siê jako odrêbny mezoregion u³aw Wiœlanych, natomiast w podziale geobotanicznym jako krainê u³awy Wis³y (Szafer 1977). Obszar deltowy Wis³y wyró nia siê m.in. terenem p³askim, najwiêkszym udzia³em powierzchniowym obszarów depresyjnych w skali kraju (por. Starkel 2001), zaznaczaj¹cymi siê wp³ywami klimatu kontynentalnego i morskiego (Kwiecieñ 1982) oraz nak³adaj¹cymi siê oddzia³ywaniami cz³owieka na naturalne procesy aluwialne rzek. Najbardziej charakterystyczn¹ cech¹ tego terenu jest bardzo bogata sieæ hydrograficzna, która stanowi oko³o 7% ca³kowitego obszaru u³aw (Matusik, Szczêsny 1976). W sk³ad wód powierzchniowych wchodz¹ du e rzeki (m.in. Wis³a, Nogat, Szkarpawa, Martwa Wis³a), mniejsze naturalne cieki (np. Œwiêta, Tina, Balewka), a tak e jezioro Druzno o powierzchni oko³o 14,5 km (Drwal 1991) oraz sztuczne cieki. Te ostatnie stanowi¹ wiêksz¹ czêœæ sieci wodnej u³aw, a ich ³¹czna d³ugoœæ wynosi oko³o km, z czego na kana³y przypada km, a na boczne rowy km (Kondracki 2002).

87 Vegetation of watercourses and their margins Materia³ i metody Prace terenowe przeprowadzono w sezonach wegetacyjnych Na obszarze delty Wis³y badaniami objêta zosta³a roœlinnoœæ wspó³czeœnie istniej¹cych cieków i ich obrze y. Poszczególne stanowiska zlokalizowano w kwadratach siatki ATPOL (Zaj¹c 1978) w postaci uszczegó³owionej, tj. w kwadratach ni szego rzêdu o boku 5 km, oznaczonych literami a-d (por. Markowski, Buliñski 2004). Badane cieki, ze wzglêdu na pochodzenie, podzielono na naturalne, tj. powsta³e bez ingerencji cz³owieka oraz sztuczne, których geneza zwi¹zana jest z bezpoœrednimi oddzia³ywaniami antropogenicznymi. Badania terenowe w naturalnych i sztucznych ciekach oraz na ich obrze ach prowadzone by³y na stanowiskach zlokalizowanych na ca³ym obszarze delty Wis³y. Za pojedyncze stanowisko przyjêto fragment cieku o d³ugoœci 50 m. W przypadku du ych rzek i kana³ów, tj. o szerokoœci przekraczaj¹cej 10 m, stanowiska znajdowa³y siê w odleg³oœci co najmniej 500 m od siebie i obejmowa³y ka - dy brzeg oddzielnie. Ogó³em badania wykonano na 241 stanowiskach, przy czym 94 znajdowa³y siê w naturalnych ciekach, a 147 w sztucznych, tj. 65 w kana³ach i 82 w rowach melioracyjnych. We wszystkich badanych obiektach wykonano zdjêcia fitosocjologiczne ogólnie przyjêt¹ metod¹ Braun-Blanqueta (Paw³owski 1977). Ujêcia syntaksonomiczne jednostek roœlinnoœci przyjêto za prac¹ Matuszkiewicza (2005), za wyj¹tkiem zespo³u Wolffietum arrhizae, który wyró niono zgodnie z opracowaniem Miyawaki i Tüxena (1960). W strefie wodnej i brzegowej cieków wykonano ³¹cznie 365 zdjêæ fitosocjologicznych. Zestawiono i opracowano 326 zdjêæ w 26 tabelach, w tym zbiorowiska wodne ujête zosta³y w 12 tabelach (126 zdjêcia), a szuwarowe w 14 (200 zdjêæ). W badaniach uwzglêdniono zbiorowiska stale lub okresowo zalewane oraz po³o one w bezpoœrednim s¹siedztwie koryt cieków. Do charakterystyki obiektów pos³u y³y pomiary szerokoœci lustra wody w cieku oraz jego g³êbokoœci, mierzone przy pomocy taœmy mierniczej i ³aty geodezyjnej. Okreœlono równie rodzaj pod³o a w korycie i opisano stan zachowania cieków poprzez uwzglêdnienie zabiegów konserwacji oraz sposobów u ytkowania najbli szego otoczenia. Informacje o stanie, funkcjonowaniu i konserwacji sieci melioracyjnej na u³awach Wiœlanych uzyskano z oddzia³ów terenowych Zarz¹dów Melioracji i Urz¹dzeñ Wodnych w Elbl¹gu, Pruszczu Gdañskim i Nowym Dworze Gdañskim (Dane Zarz¹du Melioracji ). Do okreœlenia zmian warunków wodnych pomocne by³y równie opracowania hydrologiczne tego terenu (Majewski 1969; Fac-Beneda 1999, 2002; Drwal 2000). W celu okreœlenia zró nicowania siedlisk wykorzystana zosta³a metoda biondykacyjna Ellenberga (1992). Dla gatunków w poszczególnych obiektach badañ uwzglêdniono nastêpuj¹ce wskaÿniki: odczynu (R), azotu (N) i zasolenia (S).

88 88 Renata Afranowicz Nazewnictwo roœlin naczyniowych przyjêto za Mirkiem i in. (2002), za wyj¹tkiem Polygonum amphibium f. natans, P. amphibium f. terrestre (wg Rutkowskiego 2004), a w¹trobowców za Szweykowskim (2006). W celu porz¹dkowania prób roœlinnoœci cieków reprezentowanych przez zdjêcia fitosocjologiczne zastosowano nietendencyjn¹ analizê zgodnoœci DCA (ang. Detrended Correspondence Analysis) z zastosowaniem programu CANOCO 4.5 (ter Braak, Šmilauer 2002). Metoda DCA pos³u y³a do poœredniej analizy gradientów œrodowiska, które s¹ ujawniane na podstawie sk³adu gatunkowego prób. Czynniki œrodowiska by³y charakteryzowane przez okreœlone zmienne. Jako zmienne zastosowane zosta³y kategorie cieków. Ponadto dodatkowymi zmiennymi by³y wskaÿniki: odczynu, azotu i zasolenia (por. Ellenberg 1992). Przed zastosowaniem nietendencyjnej analizy zgodnoœci wartoœci pokrycia dla poszczególnych gatunków roœlin przetransformowano ze skali Braun-Blanqueta na 7-stopniow¹ skalê porz¹dkow¹ (Lepš, Šmilauer 2004) w nastêpuj¹cy sposób: r 1, + 2, 1 3, 2 4, 3 5, 4 6, 5 7. Dla wy ej wymienionych wskaÿników Ellenberga obliczono œrednie wa one w poszczególnych zdjêciach fitosocjologicznych, uwzglêdniaj¹c iloœciowoœæ gatunków ( omnicki 2000). Do wstêpnego pogrupowania zdjêæ fitosocjologicznych zastosowano klasyfikacjê hierarchiczn¹, stosuj¹c metodê pe³nych po³¹czeñ oraz odleg³oœæ euklidesow¹ jako miary podobieñstwa. Wyniki Na badanym terenie stwierdzono wystêpowanie 34 zespo³ów roœlinnych, w tym 20 wodnych, nale ¹cych do klas Lemnetea minoris i Potametea oraz 14 szuwarowych z klasy Phragmitetea. Zró nicowanie roœlinnoœci cieków naturalnych i sztucznych przejawia siê w czêstoœci ich wystêpowania. Spoœród ogólnej liczby 34 zespo³ów roœlinnych (w tym 20 wodnych i 14 szuwarowych) a 11 zbiorowisk wystêpuje we wszystkich wyró nionych typach cieków. Z wodnych nale ¹ do nich m.in.: Lemno minoris-salvinietum natantis, Spirodeletum polyrhizae, Lemnetum gibbae, Ceratophylletum demersi i Hydrocharitetum morsus-ranae, a z szuwarowych, np. Phragmitetum australis, Acoretum calami i Glycerietum maximae. Fitocenozy reprezentuj¹ce te zbiorowiska roœlinne by³y najczêœciej spotykane na badanym terenie i stanowi³y blisko 70% wszystkich miejsc notowañ. Drug¹ grupê stanowi³y zespo³y spotykane w du ych i ma³ych ciekach naturalnych oraz ma³ych sztucznych. Nale a³y do nich zarówno zbiorowiska pleustofitów, jak: Lemnetum trisulcae, L. gibbae i Wolffietum arrhizae, jak i szuwary: Typhetum latifoliae i Caricetum ripariae. Szczególnie czêsto notowane w tej grupie by³y fitocenozy Lemnetum trisulcae i Typhetum latifoliae, które zdecydowanie najczêœciej spotykane by³y w ma³ych ciekach. Czêœæ zbiorowisk, odznaczaj¹cych siê swoistymi wymaganiami siedliskowymi, na badanym terenie notowana by³a rzadko i tylko w niektórych

89 Vegetation of watercourses and their margins typach cieków. Nale ¹ do nich fitocenozy zbiorowisk wodnych, odnotowane tylko w ma³ych naturalnych i sztucznych ciekach: Ricciocarpetum natantis, Potametum pectinati, P. friesi oraz Hottonietum palustris. Z kolei Thelypteridi- Phragmitetum odnaleziono wy³¹cznie w naturalnych ciekach, a Potametum natantis i Iridetum pseudacori obserwowano wy³¹cznie w ciekach sztucznych (por. tab. 28). Niektóre zbiorowiska roœlinne na badanym terenie zwi¹zane by³y wy³¹cznie z jednym typem cieków. I tak wyraÿnie przywi¹zane do du ych rzek by³y fitocenozy Ranunculetum circinati, Nymphoidetum peltatae i Typhetum angustifolie, natomiast wy³¹cznie w ma³ych sztucznych ciekach notowano p³aty zespo³u Polygonetum natantis oraz zbiorowisk szuwarowych: Oenantho-Rorippetum, Caricetum acutiformis i Phalaridetum arundinaceae. Zró nicowanie zbiorowisk wodnych w zale noœci od szerokoœci i typu cieku, z którym zwi¹zane jest jego pochodzenie i stopieñ oddzia³ywania antropogenicznego, przedstawione zosta³o za pomoc¹ metody DCA. Za segregacjê zdjêæ fitosocjologicznych odpowiadaj¹ pierwsza i druga oœ, które ³¹cznie wyjaœniaj¹ oko³o 30% zmiennoœci florystycznej od przyjêtych zmiennych (Ryc. 5). Zró nicowanie wzd³u pierwszej osi zwi¹zane jest ze zmiennoœci¹ sk³adu gatunkowego, natomiast z drug¹ osi¹ skorelowane s¹ wartoœci wskaÿników odczynu (R), azotu (N) i zasolenia (S). W zakresie najwy szych ich wartoœci skupione s¹ zbiorowiska Wolffietum arrhizae, Lemnetum gibbae i Elodeetum canadensis. Z najni szymi wartoœciami natomiast wyraÿnie zwi¹zane jest Nupharo-Nymphaeetum albae. Zmiennoœæ roœlinnoœci wodnej zaznaczaj¹ca siê wzd³u drugiej osi w gradiencie yznoœci siedliska i stopnia jego zasolenia jest zwi¹zana z typem i morfometri¹ cieków. Z du ymi ciekami naturalnymi i sztucznymi zwi¹zane s¹ wielkopowierzchniowe p³aty Nupharo-Nymphaeetum albae oraz Lemno minoris-salvinietum natantis. Z kolei zbiorowiska: Wolffietum arrhizae, Lemnetum gibbae i Elodeetum canadensis maj¹ optimum wystêpowania w ma³ych rzekach i kana³ach. W rowach melioracyjnych najczêœciej rozwijaj¹ siê fitocenozy Lemnetum trisulcae, Spirodeletum polyrhizae i Ceratophylletum demersi. W analizie wielowymiarowej DCA, zbiorowiska szuwarowe reprezentowane przez zdjêcia fitosocjologiczne uporz¹dkowane s¹ wzd³u drugiej osi, która wyjaœnia oko³o 17% zmiennoœci (Ryc. 6). Z ni¹ zwi¹zany jest gradient odczynu, który jest najistotniejszy, a tak e zawartoœci azotu i zasolenia. W zakresie najwy- szych wartoœci wskaÿników R, N i S grupuj¹ siê zdjêcia fitosocjologiczne reprezentuj¹ce zespo³y Typhetum angustifoliae i Scirpetum maritimi. WyraŸny podzia³ szuwaru oczeretowego na dwie grupy wynika z odmiennych warunków siedliskowych, g³ównie zawartoœci chlorków sodu oraz tworzenia fitocenoz przez jeden z dwóch gatunków charakterystycznych zespo³u. Przeprowadzone obserwacje i badania wskazuj¹, e w zale noœci od genezy i szerokoœci cieków zaznaczaj¹ siê odmienne uk³ady przestrzenne roœlinnoœci wodnej i szuwarowej. Ma³e rzeki i kana³y zajête s¹ czêsto przez zwarte fitocenozy z udzia³em Lemna minor, L. gibba, Spirodela polyrhiza, Hydrocharis morsus-ranae, a w strefie podwodnej Ceratophyllum demersum. Na ich brzegach rozwija siê w¹ski pas szuwaru Phragmitetum australis, Glycerietum maximae lub Caricetum

90 90 Renata Afranowicz ripariae. Szczególnie charakterystyczne dla krajobrazu u³aw Wiœlanych s¹ rowy melioracyjne, tworz¹ce bardzo gêst¹ sieæ, których w¹skie koryta i brzegi niemal w ca³oœci porastaj¹ zazwyczaj fitocenozy zespo³ów: Phragmitetum australis lub Typhetum latifoliae. Zupe³nie odmienn¹ fizjonomiê maj¹ du e i œrednie rzeki, do których podobne s¹ du e kana³y. Przewodnim sk³adnikiem ich roœlinnoœci s¹ wielkopowierzchniowe p³aty Nupharo-Nymphaeetum albae, pokrywaj¹ce czêsto znaczn¹ powierzchniê lustra wody. Dalej w kierunku brzegów wystêpuj¹ nierzadko, zauwa alne dopiero w drugiej po³owie lata, p³aty Lemno minoris-salvinietum natantis, a w toni wodnej Potametum lucentis. W strefie kontaktowej zbiorowisk wodnych i szuwarowych, ale wy³¹cznie du ych rzek, znajduj¹ siê fitocenozy Typhetum angustifoliae, a czêsto tak e agregacje Scirpetum maritimi z Schoenoplectus tabernaemontani oraz kêpy lub niedu e grupy Butomus umbellatus. Szeroki pas szuwaru trzcinowego Phragmitetum australis wystêpuje w du ych zarówno naturalnych jak i sztucznych ciekach, rozci¹gaj¹c siê od strefy zalewowej po brzegow¹. Wnioski Roœlinnoœæ sztucznych cieków (kana³ów i rowów odwadniaj¹cych), stanowi¹cych g³ówny element sieci hydrograficznej u³aw Wiœlanych, wykazuje znaczne podobieñstwo do roœlinnoœci naturalnych cieków. Jedna trzecia zespo³ów roœlinnych obserwowanych na badanym terenie zwi¹zana jest zarówno z naturalnymi, jak i sztucznymi ciekami oraz nie wykazuje preferencji odnoœnie do ich wielkoœci. Ponadto p³aty tych zespo³ów stanowi¹ najczêœciej spotykany rodzaj fitocenoz. Typ cieku i jego morfometria maj¹ natomiast wp³yw na rozmieszczenie typów zbiorowisk oraz wielkoœæ zajmowanych przez nie powierzchni. Intensywne oddzia³ywanie cz³owieka, zw³aszcza przeprowadzane zabiegi konserwacyjne w kana³ach i rowach odwadniaj¹cych, powoduj¹ zniekszta³cenia roœlinnoœci i siedlisk. Nowo ods³oniête siedliska opanowywane s¹ czêsto przez roœliny ekspansywne. Wyniki przeprowadzonych badañ wskazuj¹, i na u³awach Wiœlanych rowy i kana³y odwadniaj¹ce w du ym stopniu przejê³y funkcjê dawnych naturalnych koryt i starorzeczy i odgrywaj¹ wa n¹ rolê jako ostoje ró norodnoœci florystycznej i fitocenotycznej w antropogenicznym krajobrazie delty Wis³y.

91 Annex

92 Photo 1. Fragment of Wolffietum arrhizae phytocoenosis Photo 2. Fragment of Lemno minoris-salvinietum natantis phytocoenosis

93 Photo 3. Natural watercourse overgrown by phytocoenosis of Hydrocharitetum morsusranae dominated by Stratiotes aloides Photo 4. Phytocoenosis of Nupharo-Nymphaeetum albae on Nogat river

94 Photo 5. Phytocoenosis of Typhetum latifoliae in drainage ditch Photo 6. Phytocoenoses of Phragmitetum australis in the bankside of drainage ditches in agricultural landscape of the u³awy Wiœlane region