Accelerated forest restoration may benefit spotted owls through landscape complementation

Abstract

Animals often rely on the presence of multiple, spatially segregated cover types to satisfy their ecological needs; the juxtaposition of these cover types is called landscape complementation. In ecosystems that have been homogenized because of human land use, such as fire‐suppressed forests, management activities have the potential to increase the heterogeneity of cover types and, therefore, landscape complementation. We modeled changes to California spotted owl (Strix occidentalis occidentalis) nesting/roosting habitat, foraging habitat and habitat co‐occurrence (i.e. landscape complementation) within a 971 245‐ha forest landscape restoration project area, the Tahoe‐Central Sierra Initiative (TCSI) landscape, through mid‐century as a function of fuels reduction, fire and climate change. Compared to a minimal management scenario, accelerated management within the TCSI landscape was predicted to increase the number of potential 400‐ha spotted owl territories containing a high degree of landscape complementation (defined as containing >20% nest/roost habitat and >20% foraging habitat) at lower elevations (<5000 ft.) by an average of 90 to 118 territories by 2050, depending on the climate scenario examined. At higher elevations (>5000 ft.), potential benefits of treatments to spotted owl nesting/roosting and foraging habitat were less evident, but accelerated management did not result in habitat loss. Our results suggest that accelerated fuels reduction and forest restoration treatments within this large landscape are expected to benefit spotted owls by improving the spatial juxtaposition of nesting/roosting and foraging cover types by 2050 compared to a minimal management scenario. Fuels reduction and forest restoration in this landscape thus can both increase the resilience of forest ecosystems to disturbances as well as benefit the habitat of a sensitive old‐forest species.