Lynx and wolverine are viewed as the two most significant predators of reindeer in Norway. Golden Eagle is also considered an important carnivore on reindeer, but there is currently no reliable data on a national scale to estimate its impact on losses. Studies carried out in Finland suggest that golden eagle predation is mostly compensatory to other causes of mortality (Nieminen et al.). Wolves are not allowed to establish within the reindeer herding areas (they utilize 5 % of Norwegian territories along the Swedish border, south of the reindeer herding areas). Brown bear are only found on limited areas utilized by the reindeer herding industry. Less than 2% of the documented losses of reindeer are due to brown bear and wolf.
We use the number of breeding lynx and wolverine, i.e. the surveyed segment of the populations, to estimate the losses per reproduction. Estimates of losses due to Golden eagle will be included when data and methods become available.
While reindeer are usually herded within specific district borders, lynx and wolverine are known to utilize vast areas, across districts borders. Also, many of the observations of lynx and wolverine are along district borders suggesting that several districts may be affected by the same individual. In Kautokeino and Karasjok, complicated herding practices, involving sequential use by several herds of the same pastures further complicates estimation of losses at the district level. We have accordingly aggregated lynx and wolverine abundance to region rather than district level when estimating losses due to carnivores.
Simple correlations presented earlier on these pages have revealed that losses deemed due to carnivores are correlated to population size, body condition and climatic conditions, but what is the relative importance of the various predictors? Here we estimate the relative importance of food limitation and predation on the losses that is considered due to predation, early calf recruitment, and population dynamics.