Impacts of power lines on brown bear movement in central Sweden

Abstract

For decades climate change and renewable energy have been at the centre of media attention, as well as in private and public sectors. Sweden took on ambitious commitments to reduce the national emission of CO2, including promoting the switch to renewable energies, among which wind energy occupies an important place. However, its production requires building wind parks that are often placed in wildlife habitat for reasons mainly based on wind properties. Wind parks construction implies building the necessary infrastructure (roads and power lines) to support and maintain it and to transport the produced electricity. How these power lines and associated roads affect wildlife movement and behaviour remain important questions in wildlife management and conservation. Recent advances in GPS telemetry and remote sensing technologies provide researchers with abundant data that can be used to investigate detailed questions about wildlife behaviour. Using these technologies, this report aims to determine whether brown bears (Ursus arctos) are affected by power lines in their general habitat selection behaviour in the intensively managed boreal forests of central Sweden. It also intends to determine whether bears adjust their movements in the immediate vicinity of those structures. Finally, it aims to determine whether the bear’s movement responses towards power lines are ambiguous with respect to reproductive status and season. Maxent modelling showed relatively little influence of power lines on bear habitat selection, albeit that power lines explained a greater part of variation in habitat selection for specific reproductive classes and seasons. Movement analysis demonstrated that power lines had little influence on bears’ speed, with again more or less specific reactions regarding reproductive classes and seasons. Subadults, however, appeared to decrease their movement rates during the berry season. Movement analysis also demonstrated that bears’ speed is influenced by roads up to 275 metres from the feature. Management strategies may include, besides minimizing the development of power lines in bear habitat, making transmission lines unsuitable as travel routes to reduce the impacts of human development and to restore the edge areas between the corridor and the forest.