Novel insights into red deer (Cervus elaphus) habitat use and suitability in human-dominated versus near-natural landscapes

Red deer populations, once extirpated in large parts of Europe, have recovered over the last century in many regions. In Switzerland, primarily inhabiting mountain forests, they have recently started to expand into human-dominated lowland landscapes. To study their habitat selection, we analyzed day- and nighttime positions of 15 GPS-collared red deer. Our results show that during daytime, all animals generally preferred forests; open land was mainly used at night. In summer and fall, some lowland individuals deviated from this pattern and used agricultural crops as daytime retreats. Human settlements were often avoided in the lowlands. Day-site selection in the lowlands occurred irrespective of the distance to trails and the probability of being accessed by humans, in contrast to the pattern observed in the mountains. At night, red deer preferred forest edges and open land. In the lowlands, human settlements were avoided. Trails and transport infrastructures had a marginal influence at night. Our study confirmed a high behavioral plasticity of red deer. The use of daytime retreats close to trails and in high-standing crops represent major extensions of their behavior. Our habitat models indicate that there is ample suitable habitat in the lowlands, which is of major relevance for their management.