Considering hazel dormouse (Muscardinus avellanarius) home ranges to assess the impacts of development projects

Renewable energy development plays an important role in mitigating climate change, but poses challenges to biodiversity. The hazel dormouse ( Muscardinus avellanarius ), a protected arboreal mammal, is increasingly at risk due to wind turbines being located into forested areas more frequently. This study theoretically examines the effects of clear-cuts on hazel dormouse home ranges. The home range data of two seasons of a long-term monitoring in Lithuania was digitised using QGIS. The home ranges were intersected with simulated clear-cuts of varying shapes (strip, square) and sizes (1, 2, 4, 6 ha) under low and high population densities. The number of home ranges affected and the percentage of area overlapped per home range were modelled using GLMs with Poisson distributions and beta regressions. A 1 ha clear-cut typically intersected multiple home ranges: median two at low density and four at high density, with up to twelve in high-density, square-cut scenarios. Larger clear-cuts affected more home ranges and a greater fraction of each home range, with steeper increases at high density. Square shaped clear-cuts overlapped a higher percentage of individual home ranges than strip-shaped ones, whereas strips intersected a higher total number of home ranges at high density. Females had smaller home ranges and experienced higher proportional overlap with clear-cuts than males. As nest-box data likely underestimate true home range size, our estimates are conservative for the number of home ranges affected. The results indicate that the 1 ha equals one home range approach currently used for development measure in Germany underestimates the effects on home ranges and should be replaced by site-specific planning that considers density, clear-cut geometry and sex-specific vulnerability.