Species richness - pond area relationships of amphibians and birds in two Natura 2000 protected areas of Romania

In this paper, we present regional differences in pond area by focusing on species - pond area relationships between two groups of vertebrates differing in life cycles and ecological requirements: amphibians and birds. The study was conducted in two regions of Romania: the Tarnava Basin and the Fize Valley. Ponds from Tarnava were more vegetated with emergent aquatic plants (Phragmites australis and Typha sp.). The amphibian species richness in ponds was higher in Tarnava than in Fize and, conversely, Fize contained a higher number of bird species. The diversity of the amphibian species is not related to pond area, however, there was a positive relationship in both regions between amphibian species richness and the percentage of emergent vegetation cover. Bird's species richness, on the other hand, was positively related to both pond area and vegetation cover in Tarnava whereas only to vegetation cover in Fize. The z values of the species-area relationship for amphibians were low in both regions and slightly negative in Tarnava. In case of birds, the z value was larger in Tarnava than in Fize, suggesting that the number of species increased more with pond area in Tarnava than in Fize.