The conservation of small water reservoirs in the Krajeńskie Lakeland (North-West Poland)

摘要

This study comprised an inventory of vascular plants in 450 small water reservoirs (up to 1. ha in size). Most water bodies (76%) in the study area (Krajeńskie Lakeland, NW, Poland) were located in an agricultural landscape, typical of the region. A total of 576 species of vascular plants were recorded. Of these, about 76% were native species, 34 taxa were listed as legally protected in Poland and endangered in the region (Western Pomerania) or in Poland. 201 plant communities were identified, including 128 associations. Depending on the surrounding habitat, the following groups of ponds were identified: (1) mid-forest ponds; (2) mid-wetland ponds; ponds between arable fields, including (3) water basins with wide, well developed ecotone zones and (4) ponds with narrow or disturbed contact zones; and (5) ponds in urban areas. 30 ponds of each type were compared in detail. Differentiation and plant species richness of small water reservoirs was dependent on landscape type. The richest ponds were located within fields but isolated from their surroundings by a natural belt of rushes or trees, whilst mid-forest ponds were the poorest. Valorization was based on the presence of valuable flora (e.g. native, rare, and endangered species) and plant communities. This revealed that mid-forest and mid-wetland ponds were the most natural, while ponds in urban areas were the most strongly transformed. Ponds in the study area (n= 450) were also analysed for anthropogenic impacts. Anthropogenic stressors were observed in 51% of ponds. The most serious threats to the ponds of the Krajeńskie Lakeland were deterioration due to drainage and eutrophication. Over 35% of ponds were connected to a network of drainage ditches, with the highest percentage (57.1%) found in mid-forest ponds type.