What makes for a good location? : Terrain ruggedness and reindeer drive detection of Eurasian lynx (Lynx lynx) by camera traps in northern Sweden

Sammanfattning

As all large carnivores in Europe, the Eurasian lynx’s presence in a landscape now dominated by human activities often leads to conflictual situations and management challenges. To overcome these issues, different monitoring programs are developed all over Europe to assess for the abundance and distribution of this elusive feline. Camera trapping could become a substantial monitoring census tool in Sweden were the decrease in snow cover through climate change and the expansion of the lynx towards southernmost areas could lead to a necessity in changing the current monitoring program based on snow-tracking. The purpose of this study was to understand, looking into the future implementation of camera trap-based lynx monitoring programs, the impact of different environmental variables on the detection of the Eurasian lynx by camera traps. To do so, I designed and ran a camera trap study to detect lynx in Northern Sweden while extracting environmental variables on each camera location. These included habitat variables – terrain ruggedness, field cover, water body proximity –, microsite variables – microsite type – as well as prey prevalence variables – reindeer, roe deer and mountain hare passage rate – I then computed Generalized Linear Models (GLM) to compare each variable between each other regarding lynx detection probability and determine the ones with the greater impact on lynx detection. I found that terrain ruggedness and reindeer passage rate had the greater impact on the detection of lynx. In conclusion, while most variables did not affect the detection of lynx, these two had a significant impact on lynx detection, showing how focusing on specific environmental features might increase the quality of a lynx monitoring program based on camera trapping. With more focus placed on understanding what other variables or factors could impact lynx in other areas in Southern Sweden, camera trapping could become a realistic alternative to the current monitoring programs.