Research needs to support management and conservation of cavity-dependent birds and bats on forested landscapes in the Pacific Northwest

Snags provide habitat for numerous vertebrates and invertebrates. We review how current regulatory guidelines and forest management practices influence snag populations on intensively managed landscapes in the Pacific Northwest. We identify ecological relationships that require investigation to assess alternative practices that optimize ecological and economic goals. Functional and numerical relationships among snag type, abundance, and distribution and demographic responses of both vertebrates and invertebrates are poorly understood. Relatively little is known about temporal and spatial distributions of snags required to maintain viable populations of cavity-dependent taxa or how landscape-scale features (e.g., proximity and amount of mature and late-successional forest) interact with snag types and distributions at the stand level to influence wildlife responses. Regulations for snag retention have been developed and implemented with a substantial degree of uncertainty about their ecological effectiveness. Current regulations, designed to protect forest workers from injury, typically limit retention of snags of large size and advanced decay classes that are often the most limited snag types on intensively managed landscapes. We describe current findings and future research needs that can be used to evaluate operational and ecological effectiveness of current regulations that influence snag management. We identify questions of interest and frame these within the appropriate ecological context of intensively managed landscapes.