Analysis of the human footprint on reindeer summer habitat. Using habitat selection modeling to assess anthropogenic drivers of habitat loss in Norwegian wild mountain reindeer (Rangifer tarandus tarandus)

Abstract

1) Of particular importance to wildlife conservation and mitigation of the current biodiversity crisis are questions of habitat loss and degradation. In this context, disturbance studies have sought to implement new methods for studying wildlife populations in relation to their environment when subjected to the human footprint. Habitat selection models have proven to be powerful tools for quantifying the impact of human disturbances on wildlife habitat and estimating disturbance parameters influencing spatial and temporal distribution of a species from occurrence data. 2) During the last century, Norway has experienced fast-paced infrastructure development that has resulted in the massive loss of mountain wilderness. In those same mountains live the last remaining populations of wild mountain reindeer (Rangifer tarandus tarandus) in Europe. With pervasive human influence and multiple claims placed on Norwegian mountains, seasonal habitat loss is currently suggested as the main threat for wild reindeer in southern Norway. Accordingly, the Norwegian Government is investing considerable resources into habitat loss assessment, as a critical step to determine if these areas will be able to support viable population units in the future. 3) With the purpose to unravel and quantify the drivers of anthropogenic habitat loss in wild reindeer summer habitat, the present research investigated reindeer habitat use on summer ranges in relation to the human footprint in southern Norway, using existing resource selection functions (RSFs), developed for wild reindeer, and GPS data. Overall, human disturbances were found to induce substantial habitat loss (> 50%) in wild reindeer summer ranges. However, differences could be noted between herds, both in relation to the uneven spatial distribution of the human footprint and the main drivers of anthropogenic habitat loss, which were found to vary between reindeer areas. For the study area as a whole, highest avoidance levels during summertime were induced by the grazing animals from domestic livestock, primarily, as well as by houses of the domestic sector, low traffic summer roads and hiking trails. 4) The present human footprint analysis points out the need for prioritized management and targeted mitigation of herd-specific disturbance sources in wild reindeer ranges. Moreover, it provides key insights for the future prevention of human-reindeer conflicts and will hopefully help to balance wild reindeer conservation with anthropogenic development. This study and the approach it proposes may provide a valuable framework for quantifying the impacts of the human footprint in further biodiversity components, and thus help tackle the loss of natural habitats.