Factors affecting predation of red foxes Vulpes vulpes on brown hares Lepus europaeus during the breeding season in Poland

The aim of my Study was to estimate the effect of brown hare Lepus europaeus density, vole abundance and habitat diversity oil the Occurrence of hares in the diet of red fox Vulpes vulpes during the breeding season in agricultural landscapes. I used the average number of adult hares found among food remains scattered around a number of breeding dens of foxes (10-24/year), and analysed its temporal variation during 1997-2006 in an area located in western Poland; furthermore, I analysed the spatial variation based on results from 21 areas in various other regions of the country. Spring hare density, vole abundance index (logarithm of the number of burrow entrances/km) and habitat diversity (number of Structural elements/km) were estimated using line transects of 20-61 km. In the low hare density area (5-10 individuals/km(2)) in western Poland, the number of hares/fox den was influenced by hare density rather than by vole abundance. In the various areas with high hare densities (11-28 individuals/km(2)), multiple t regression analysis showed a positive effect of hare density (R-2=40%) and a negative effect of vole abundance index (R-2=24%) oil the number of hares/fox den, whereas the effect of habitat diversity index (R-2=13%) was only close to being significant. In the case of low hare density range (1-10 individuals/km(2)), the number of hares/fox den decreased with the habitat diversity index (R-2=56%). Therefore, proper habitat management in agricultural areas should lead to a reduction of red fox pressure oil brown hare, especially in areas with low-density hare Populations.