Local habitat association does not inform landscape management of threatened birds
Context: Species that use open patches in forested landscapes often select clearcuts. However, it is unknown whether local associations with clearcuts translate to an effect of clearcut amount in the surrounding landscape on occupancy or abundance at local sites. This question is important because forest management decisions are made at landscape scales. Objectives: We examined whether the amount of clearcut in the surrounding landscape influenced site occupancy of two threatened aerial insectivores, Common Nighthawk and Eastern Whip-poor-will. Both species nest in/near clearcuts at a local-scale. Methods: We used acoustic recorders placed on edges of recent clearcuts (≤ 15 years old, n = 49 sites) to measure presence-absence. We estimated occupancy in relation to the proportion of clearcut and open wetland within the surrounding landscapes at spatial extents between 0.5 and 5.0 km. Results: Occupancy of Eastern Whip-poor-will was not related to clearcut amount in the surrounding landscape at any scale. Common Nighthawk occupancy was lower in sites surrounded by landscapes with higher proportion of older (11–15 years old) clearcuts. Both species’ occupancy was higher in sites where the surrounding landscapes had higher proportions of open wetland. Conclusions: Two possible mechanisms for our results include multi-scale selection of breeding sites or demographic responses to higher productivity in wetlands than clearcuts; both need further study. Our results show how the association of species with clearcut habitats at a local scale does not necessarily translate to a higher occurrence of those species at the landscape scale at which management decisions are made.
|Keywords||Aerial insectivore, Cross-scale extrapolation, Forest management, Landscape composition, Scale of effect, Wetlands|
Farrell, C.E. (Claire E.), Fahrig, L, Mitchell, G. (Greg), & Wilson, S. (2019). Local habitat association does not inform landscape management of threatened birds. Landscape Ecology. doi:10.1007/s10980-019-00843-6