Survival rates and causes of mortality in Eurasian lynx ( Lynx lynx) in multi-use landscapes

Abstract

Causes of mortality were described for 245 radio-marked Eurasian lynx ( Lynx lynx) in five different Scandinavian study areas. Furthermore, the survival rates and the population growth rates were estimated for three of the study areas where 202 lynx were followed for a total of 314 radio-years. The main causes of mortality in adult Eurasian lynx in all our study areas were overwhelmingly anthropogenic, with starvation, vehicle collisions, intra- and interspecific killing and disease only having a minor role. The mean mortality rates for adults increased from 2% to 17% when hunting and poaching were included, i.e., an increase by a factor of eight. This in turn had a large impact on population growth rates, which changed from more than a 20% annual increase to only a 2–4% when hunting and poaching were included. Poaching accounted for 46% of the mortality in adult lynx. Poaching and legal harvest appear to be primarily motivated by conflicts; lynx depredation on semi-domestic reindeer in northern Scandinavia, competition with hunters for roe deer in southern Scandinavia, and depredation on free-ranging domestic sheep in all Norway. The lowest poaching rate was found in the Hedmark study area in Norway, which also had a high legal harvest. The poaching rate was higher in one of the Swedish study areas (Sarek) where legal hunting was lower than in other areas. On the other hand, both the poaching rate and the legal harvest were high in the Akershus/Østfold study area in Norway. Thus, there does not seem to be a simple relationship between an increased legal harvest and decreased poaching as is commonly expected. The most important conservation actions are to combat poaching through both law enforcement and measures designed to increase tolerance.