Pond and landscape characteristics — which is more important for common toads (Bufo bufo)? A case study from central Romania

The primary anthropogenic factor causing amphibian declines in Europe is habitat loss and fragmentation. Here we explore the effects of aquatic and landscape habitat variables on the adult counts of the Common Toad (Bufo bufo) in 43 ponds in central Romania surveyed between 2000 and 2005. Principal components analysis (PCA) identified two main factors, with which the adult counts can be related the first related to landscape variables (percentage of forest cover, presence/absence of roads and habitat corridors) and the second, to pond variables, in particular the presence/absence of fish, together accounting for 49% of the total variance. Analysis of variance (ANOVA) showed differences between ponds where toads were present or absent in factor loadings of both principal components, but only the landscape factor was significantly correlated with toad counts. These results highlight the role of landscape composition and configuration in maintaining toad populations in this area, and suggest a negative effect of landscape fragmentation. To efficiently protect amphibians in Romania, appropriate legislation and a close collaboration between landowners, landscape planners and herpetologists are needed.