Occurrence Probability Pattern of Water-tolerant Small Mammals in a Ramsar Wetland Area in Central Europe

Abstract Kis-Balaton is regarded as the largest marshland in Central Europe. Its small mammal communities consist of several protected shrews and rodents, including the Pannonian Root Vole Alexandromys oeconomus mehelyi , a postglacial relict subspecies. Small mammals play a variety of fundamental roles in ecological networks; thus, they are commonly chosen as indicators in wetland studies. Our study was carried out in two areas of the Kis-Balaton wetland in the period between 2007 and 2024. First, we examined the difference in the community structure of small mammals using PERMANOVA and NMDS analysis. Then, we investigated the co-occurrence pattern of species. In addition, Generalized Additive Models were used to determine the occurrence probability of six water-tolerant species as a function of spatial and temporal predictor variables in Kis-Balaton. Our results showed that the community structure of small mammals was similar in both monitored areas. The co-occurrence analysis revealed a positive association between numerous species. According to the GAM modeling, the occurrence probability significantly differed for several species in the comparison of investigated areas, with the partial main effects of years and areas being determining factors. A direct partial effect of monthly rainfall was shown in the case of the Common Shrew and Short-tailed Field Vole, for which species the change of occurrence probability was correlated with the variation of rainfall. Monthly rainfall had a significant effect on the occurrence probability of the Striped Field Mouse and the Harvest Mouse as a predictor in tensor product interaction models.