Long term data on the amphibians of Wrocław

Abstract

The paper presents information about the amphibian species in Wroclaw – frequency oftheir occurrence as well as number of individuals in water bodies. For the study 31 sites were selected. Only in two sites no amphibians were found. On the rest of the sites in total 11 amphibian taxons were present – Triturus cristatus, Triturus vulgaris, Bombina bombina, Bufo bufo, Bufo viridis, Hyla arborea, Pelobates fuscus, water frogs from the Rana esculenta complex (both a species Rana lessonae and a hybrid Rana kl. esculenta), Rana temporaria and Rana arvalis. The most numerous were water frogs (occurred on 90.3% of all sites), Bufo bufo (48.4% sites), Bombina bombina and Rana temporaria (both species on 45.2% si- tes). The rarest species were Triturus cristatus (16.1% sites) and Pelobates fuscus (9.7% sites). In Wroclaw amphibians are the most abundant in ponds located within river valleys. There are 10 species there (on the average 4.44 species per pond), with Bombina bombina and water frogs being the most numerous. Second amphibian-friendly environment are sites within the city forests, having 8 species (on the average 5.22 species). Water frogs, Rana temporaria and Rana arvalis were most common here, and Triturus cristatus and Triturus vulgaris occurred mostly in this category. The lowest frequency was observed in the city center (on the average 0.66 species), with one site without any amphibians, and with only water frogs in the remaining two sites. After a pond reconstruction populations of Triturus vulgaris and Bufo bufo disappeared, and the number of Bufo viridis increased. For three sites the changes in amphibian species assemblages in consecu- tive years of observations are provided. In two sites the trend of maintaining the same species composition was observed, and on third site the composition changed due to the pond reconstruction (T. vulgaris and B.bufo substituted by B. viridis).