Red deer in confined nature areas have smaller ranges and move less than red deer in unconfined areas

Fenced areas are commonly used for conservation purposes or to prevent human-wildlife conflicts. However, their use is controversial since they create barriers blocking the movements of terrestrial species, thereby potentially impeding their biological needs and ecological functions. Using >440,000 GPS positions of 37 female red deer (Cervus elaphus) from 3 fenced and 3 unfenced populations in Denmark, we calculated daily and monthly range areas, hourly and daily step length, hourly turning angles and activity (accelerometer data) to quantify the impact of fencing on deer space use and movement at different spatiotemporal scales. Using additive mixed-effects models, we investigated how range areas and movement behavior varied according to the presence or absence of fencing, while accounting for seasonal variation, supplementary feeding, age class, forest cover, and population density. Despite all fenced areas by far exceeding range sizes of unfenced hinds, unfenced hinds had >4-fold larger range areas and moved twice as large distances per day and hour than fenced hinds, with stronger seasonal variation in unfenced compared to fenced areas. However, fenced and unfenced hinds had similar average turning angles and activity levels. Our findings show that confined population space resulted in reduced space use and mobility without affecting total, seasonal and diel activity patterns strongly. This points to the necessity for an increased understanding of confinement effects on animal movements and behavior, which is especially important in the light of planned rewilding projects based on fenced wildlife across the globe.