Roe deer population growth and lynx predation along a gradient of environmental productivity and climate in Norway

Abstract

The extent to which large carnivores compete with hunters for harvestable populations of wild ungulates is a topic of widespread controversy in many areas of the world where carnivore populations are recovering or are reintroduced. Theory predicts that predation impacts should vary with prey density and environmental conditions. To test this prediction, we analyzed trends in an index of population abundance of roe deer (Capreolus capreolus) over 9 y in 144 Norwegian municipalities. The municipalities span a wide range of landscapes and climatic conditions and were associated with a varying degree of Eurasian lynx (Lynx lynx) presence. There was a wide variation in trends of roe deer abundance (estimated long-term average λ ranging from 0.69 to 1.23) among municipalities. Roe deer population growth rates were lower in the municipalities with lynx and harsh climatic conditions than in municipalities with mild climatic conditions and/or without lynx. Thus, lynx presence appears to be having a negative impact on roe deer populations; this was especially evident in areas with unfavourable environmental conditions. Our finding that estimated long-term average values of λ were less than 1 in many municipalities indicates that roe deer populations in Norway may not be able to sustain current combined mortality from hunters and lynx, especially in marginal areas.