Habitat suitability model for Polish wolves based on long‐term national census

Abstract

AbstractThe central‐European population of wolves Canis lupus has its western border of contiguous range in eastern Poland. Protected since 1998, Polish wolves began to expand towards the west. Based on large‐scale data on wolf abundance (2000–2006) and geographic information system (GIS) tools, we built a habitat suitability model (HSM) for the species in Poland. The best model, selected by the Akaike information criterion, of the resource selection function (RSF) by wolves included percentage cover of forests, meadows and marshes (positively correlated to wolf abundance) and road density (negatively correlated), and explained 53% of the total variation in the wolf abundance index in a 10 × 10 km cell grid. That RSF was then used to evaluate the whole country in terms of suitability for wolves. Potential wolf range appeared to consist of 24 patches of good habitat (predicted relative probability of wolf occurrence ≥30%), including six patches already occupied and 17 new ones. In total, habitat suitable for wolves covers at least 20–24% of Poland, compared with 16% of the country's area now occupied by the species. HSM was validated with historical data on wolf occurrence in 1950–2006. The areas selected by our model and those inhabited by wolves in at least one decade overlapped in 81–86%. Furthermore, the probability of wolf occurrence predicted by the model correlated positively with the number of decades the wolves were actually recorded in the area. Based on the empirical relationship between patch size and wolf numbers, we estimated that Poland could support a population of 1450–1540 wolves, two to three times larger than the current estimate. HSM needs to be supplemented with a GIS‐based connectivity analysis among patches, which in turn should be validated by molecular genetics studies on dispersing wolves. Because of broadly similar geographic conditions, the model may be applicable to eastern Germany, Belarus Republic and the Baltic States (Lithuania, Latvia, Estonia).