Needle in a Haystack: Predicting the Occurrence of Wetland Invertebrates on the Basis of Simple Geographical Data. A Case Study on Two Threatened Micro-Mollusc Species (Gastropoda: Vertiginidae) from Poland

Abstract

The aim of this study was to evaluate whether simple geographical data can be used to predict the probability of the presence of two threatened snail species: Vertigo angustior and V. moulinsiana, occurring within wetland areas across their central European range. Our research was based on data from 226 localities across Poland fitting with the species requirements according to the current literature. We used Canonical Variance Analysis with variance partitioning and tree classifications to model relationships between the species presence/absence and rough geographic features describing each locality (landscape and geomorphological types and hydrography). Our results have shown that the localities of the studied species are related to particular types of landform and landscape and are not distributed uniformly. Both species occur predominantly in young postglacial lowland landscapes and are usually associated with particular succession stages of lakes, with V. moulinsiana occurring in earlier phases of habitat evolution. Results from modelling show that cost- and time effectiveness of surveying for these species could be substantially increased by avoiding particular location types. The prediction models presented will be a useful tool for planning future surveys of the vertiginids and in studies on their ecology and distribution.