engleski

Body condition of Salamandra salamandra in the Pokupsko basin, Croatia

Estimating the body condition of amphibian populations is important because it may reflect habitat quality. Body condition index can be calculated from routinely collected length and weight data of individuals. The aim of this study is to determine body condition for Salamandra salamandra population in a landscape heavily influenced by human activities. The extensive alterations at Pokupsko basin has resulted in changes in wetland hydrology and a probable shift in the relative abundance of amphibian species. Condition indices of the fire salamander population were estimated over a 3 year period capture-mark-recapture study in an area of 4, 25 ha in the temperate forest in central Croatia, where 4 permanent plots were installed. This study was based on body measurements for 90 adults and juveniles from the fire salamander population. I compared the residuals from ordinary least squared regressions of salamander weight to total length as an index of body condition. A Kruskal-Wallis one-way ANOVA was used to test for differences in body condition among permanent plots and among seasons during the study. Results indicated significant differences in residuals between the two plots (K = 3, 92, df =1, p = 0, 05). Salamanders with positive residuals and thus better body condition were captured in the plot situated in the forested area with better habitat conditions (e.g. proximity of forested pond). Season had no significant effect on residual index (K = 0, 001, df =1, p = 0, 05), but the test showed that residuals were positive in spring and negative in autumn. The residual index is a useful tool in monitoring and conservation of amphibian populations because it is correlated with habitat quality and can be used to interpret the effects of environmental factors.

body condition index; Salamandra salamandra; forest disturbance; conservation

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