Quantitative biogeography of Orthoptera does not support classical qualitative regionalization of the Carpathian Mountains

Abstract

The first biogeographical division of the Carpathians, the second largest mountain range in Europe, was based on qualitative observational floristic data > 100 years ago and has also been applied for the regional zoogeography. In this study, the recent availability of detailed quantitative data allowed us to perform a more powerful evaluation of the classical biogeographical regions of the area. Thus, we analysed updated distribution patterns of 137 Orthoptera species native to the Carpathian Mountains and, by using published species range maps, we compiled data on species presence or absence within 2576 cells of a 10 km × 10 km universal transverse mercator grid in the area. Pattern analysis of the data was based on non-metric multidimensional scaling and clustering using six different algorithms applied to a βsim dissimilarity matrix. The unweighted pair-group method using arithmetic averages, which gave the best performance in the analysis of species turnover, delineated four regions. Environmental variables and species richness were used in logistic regression as predictors of delineated clusters, and indicator species were identified for each of the inferred regions. The pattern can be explained, in part, by environmental variables and species richness (34.2%) and was also influenced by connections with the orthopterofauna from adjacent areas. The observed discrepancy between regionalization based on expert knowledge and the pattern revealed using quantitative data provides a warning that the biogeography of the Carpathians might also have been revised in other taxa, where only classical qualitative regionalization exists.