Is green the new black? Black-backed Woodpecker vital rates do not differ between unburned and burned forests within a pyrodiverse landscape

摘要

Woodpeckers often reflect rapid changes to forest health and serve as indicator species to help guide forest management decisions. The Black-backed Woodpecker (Picoides arcticus) is known for its strong association with recently burned forests and is a species of conservation concern due to habitat loss stemming from post-fire management of burned forest. Several studies have found the Black-backed Woodpecker occupying extensive areas of unburned (i.e., green) forests in the western part of its range during the breeding season, raising questions about whether green forests can support viable nesting populations in this region. We studied breeding Black-backed Woodpeckers in southern Oregon, USA to evaluate whether 2 vital rates critical to population recruitment-nest survival and post-fledging survival-differed between green and burned forests. During 2018, 2019, and 2021, we monitored 91 Black-backed Woodpecker nests (n = 34 in green forest, n = 57 in burned forest) and found that neither daily nest survival rate nor reproductive output (i.e., the number of fledglings per successful nest) differed between nests located in green and burned forest; however, nestling body condition was slightly enhanced in green forest. We also quantified survival of recently fledged individuals using VHF radio telemetry and found that the survival rate of birds in green forest was nearly identical to those in burned forest, with most mortalities occurring within 4 weeks of fledging. Our results indicate that Black-backed Woodpeckers in green forests were equally successful at breeding as conspecifics in recently burned forest, although densities of nesting pairs in green forest were lower than those in burned forest. Our findings indicate certain types of green forest, particularly mature lodgepole pine, can support viable populations of the Black-backed Woodpecker in the western portion of its range. This finding has conservation implications given that green forest occupies much of the forested landscape in this region and is often juxtaposed to areas subjected to high severity fire. Therefore, practices that promote pyrodiversity-landscape-level spatial and temporal variability in fire effects-as well as connectivity between green and burned forest within fire-prone landscapes are likely to provide the greatest conservation benefit for this species.