Skip to Main Content
Conservation planning for species recovery under the Endangered Species Act: A case study with the Northern Spotted OwlAuthor(s): Jeffrey R. Dunk; Brian Woodbridge; Nathan Schumaker; Elizabeth M. Glenn; Brendan White; David W. LaPlante; Robert G. Anthony; Raymond J. Davis; Karl Halupka; Paul Henson; Bruce G. Marcot; Michele Merola-Zwartjes; Barry R. Noon; Martin G. Raphael; Jody Caicco; Dan L. Hansen; Mary Jo Mazurek; James Thrailkill
Source: PLOS ONE. 14(1): e0210643.
Publication Series: Scientific Journal (JRNL)
Station: Pacific Northwest Research Station
Download Publication (3.0 MB)
DescriptionThe northern spotted owl (Strix occidentalis caurina) was listed as threatened under the U.S. Endangered Species Act (ESA) in 1990. We applied modern spatial conservation theory and models to evaluate several candidate critical habitat networks, and sought an efficient conservation solution that encompassed the highest value lands for spotted owl recovery rather than maximizing the total area of potential critical habitat. We created a map of relative habitat suitability, which served as input to the spatial conservation prioritization program Zonation. We used the spatially-explicit individual-based population model HexSim to estimate and compare simulated spotted owl population outcomes among a suite of candidate critical habitat networks that varied in size and spatial arrangement under alternative scenarios of future habitat suitability and barred owl (S. varia) effects. We evaluated simulated spotted owl population outcomes, including total population size, and extinction and quasi-extinction likelihoods for 108 combinations of candidate critical habitat networks by habitat change by barred owl scenarios, both range-wide and within 11 distinct portions of the owl’s range. Barred owl encounter rates and the amount and suitability of habitat had substantial effects on simulated spotted owl populations. When barred owl encounter rates were high, changes in the amount and suitability of habitat had minimal impacts on population performance. Under lowered barred owl encounter rates, candidate critical habitat networks that included most existing high suitability habitat supported a high likelihood of long-term population persistence. Barred owls are currently the primary driving force behind poor population performance of NSOs; however, our models demonstrated that a sufficient area of high suitability habitat remains essential for recovery when effects of barred owls can be reduced. The modeling approach we employed is sufficiently flexible to incorporate new information about spotted owls as it becomes available and could likely be applied to conservation planning for other species.
- Visit PNW's Publication Request Page to request a hard copy of this publication.
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationDunk, Jeffrey R.; Woodbridge, Brian; Schumaker, Nathan; Glenn, Elizabeth M.; White, Brendan; LaPlante, David W.; Anthony, Robert G.; Davis, Raymond J.; Halupka, Karl; Henson, Paul; Marcot, Bruce G.; Merola-Zwartjes, Michele; Noon, Barry R.; Raphael, Martin G.; Caicco, Jody; Hansen, Dan L.; Mazurek, Mary Jo; Thrailkill, James. 2019. Conservation planning for species recovery under the Endangered Species Act: A case study with the Northern Spotted Owl. PLOS ONE. 14(1): e0210643. https://doi.org/10.1371/journal.pone.0210643.
KeywordsNorthern spotted owl, old-growth forest, Northwest Forest Plan, threatened species.
- The past and future roles of competition and habitat in the range‐wide occupancy dynamics of Northern Spotted Owls
- The roles of competition and habitat in the dynamics of populations and species distributions Ecology
- Review of the effects of barred owls on spotted owls
XML: View XML