Persistence of Capercaillie (Tetrao urogallus) lekking areas depends on forest cover and fine-grain fragmentation of boreal forest landscapes

Abstract

We studied the effects of habitat loss, fragmentation and their interaction on the persis-tence of Capercaillie lekking areas at three study areas in Finland. We inspected a total of 381 leks twice with an interval of 10–30 years, and classified them as persisting versus ceased leks. We attempted to explain the persistence of Capercaillie leks with forest cover and fine-grain fragmentation at two spatial scales (within 1,000 m and 3,000 m from the leks) by using satellite-image based forest-inventory data. We statistically removed the effect of forest cover from the measure of fragmentation, and used information-theoreti-cal model selection to evaluate a set of logistic regression analyses. Fine-grain forest frag-mentation had a positive effect on lek persistence. Forest cover positively affected lek per-sistence only when considering the landscapes surrounding the leks (within 3,000 m radius). In addition, we found a significant negative interaction between forest cover and fragmentation. Under conditions of low forest cover, patch configuration may become in-creasingly important for the persistence of lekking areas. According to our results, the most effective management strategies for Capercaillie lekking areas include maximizing the amount of forest around the lekking areas, and encouraging mosaic-like variability of the forest.