In the agricultural landscape of southern Wielkopolska (Krotoszyn area) common ecological niches such as field tree and shrub lots, boundary strips between cultivated land, paths and ponds are accompanied by small bodies of water, which often are distributed geometrically. These are remnants of marl mining in the second half of the 19th century. Currently these reservoirs disappear: they dry up or are filled by farmers. The author discusses their existence in the ecosystem.
The paper presents results of examination on the aquatic and rush vegetation of 27 small enclosed bodies of water in the vicinity of Tarnowo Podgórne (Wielkopolska Region). 20 types of phytocenoses belonging to the class Lemnetea, Potametea and Phragmitetea were distinguished, basing on the analysis of 119 phytosociological relevés carried out according to Braun-Blanquet method. Species of Phragmitetea class dominated in the most of ponds. Submerged macrophytes dominated in eight bodies of water, with one distinct dominant species among them Myriophyllum verticillatum.
37 small mid-field ponds were studied in 1993-1996. All ponds were habitat islands surrounded by agricultural landscape. The ponds size ranged from 0.1 to 4.5 ha. 13 microhabitats were distinguished within the water bodies and their shore zones. Each pond was surveyed 2-6 times during one breeding season. The number of breeding pairs of territorial species has been derived from the maximal count of simultaneous records of singing males. Other species were estimated on the basis of the number of adults in the peak of the breeding period. 572 pairs of 54 species were recorded. The dominant species were: Acrocephalus scirpaceus, Emberiza schoeniclus, Acrocephalus palustris, Fulica atra, Emberiza citrinella and Anas platyrhynchos. The water bodies area and microhabitats number were important factors which influenced the numbers of species and pairs in water bodies surveyed. In the most cases, the species on the ponds were represented by a single pair. In comparison to other lakes in NW Poland, small mid-field ponds are an important breeding biotope for: Anser anser, Podiceps grisegena, Gallinula chloropus and Rallus aquaticus.