Spatial activity and population size of the green toad (Bufotes viridis) in a large city

Abstract Spatial activity of toads outside their breeding pool is associated mainly with foraging, roosting and dispersal. Viability of populations in urban environment may therefore be affected by physical barriers (buildings, roads) or various anthropogenic disturbances (traffic, human presence) in their home-ranges. To get an idea about the potential impact of such structures and activities on the local urban population, we assessed spatial activity and population status of three isolated Bufotes viridis populations using radio-tracking of 46 individuals in the city of Košice in eastern Slovakia. Whereas core-range sizes differed only marginally (0.44–5.34 ha), home-range sizes among populations differed significantly (2.32–18.35 ha), probably as a result of local architecture’ pattern. During two years of capture-mark-recapture research, we caught 420 unique individuals, which were identified via dorsal spot pattern or PIT tags. Estimated population sizes via POPAN model ranged from 112 to 191 individuals. We assume that the current population in Košice city may be influenced by the ever-changing urban environment.