HOW BIG AND HOW CLOSE? HABITAT PATCH SIZE AND SPACING TO CONSERVE A THREATENED SPECIES
Article first published online: 20 JUL 2012
2012 Wiley Periodicals, Inc. Published 2012. This article is a U.S. Government work and is in the public domain in the U.S.A.
Natural Resource Modeling
Volume 26, Issue 2, pages 194–214, May 2013
How to Cite
MARCOT, B. G., RAPHAEL, M. G., SCHUMAKER, N. H. and GALLEHER, B. (2013), HOW BIG AND HOW CLOSE? HABITAT PATCH SIZE AND SPACING TO CONSERVE A THREATENED SPECIES. Natural Resource Modeling, 26: 194–214. doi: 10.1111/j.1939-7445.2012.00134.x
- Issue published online: 22 APR 2013
- Article first published online: 20 JUL 2012
- Received by the editors on 23 April, 2012. Accepted 04 June, 2012.
- Dispersal model;
- Northern Spotted Owl;
- habitat size;
- habitat spacing;
- HexSim model;
- threatened species
Abstract. We present results of a spatially explicit, individual-based stochastic dispersal model (HexSim) to evaluate effects of size and spacing of patches of habitat of Northern Spotted Owls (NSO; Strix occidentalis caurina) in Pacific Northwest, USA, to help advise recovery planning efforts. We modeled 31 artificial landscape scenarios representing combinations of NSO habitat cluster size (range 4–49 NSO pairs per cluster) and edge-to-edge cluster spacing (range 7–101 km), and an all-habitat landscape. We ran scenarios using empirical estimates of NSO dispersal dynamics and distances and stage class vital rates (representing current population declines) and under adult survival rates adjusted to achieve an initially stationary population. Results suggested that long-term (100-yr) habitat occupancy rates are significantly higher with habitat clusters supporting ≥25 NSO pairs and ≤15 km spacing, and with overall landscapes of ≥35–40% habitat. Although habitat provision is key to NSO recovery, no habitat configuration provided for long-term population persistence when coupled with currently observed vital rates. Results also suggested a key role of floaters (unpaired, nonterritorial, dispersing owls) in recolonizing vacant habitat, and that the floater population segment becomes increasingly depleted with greater population declines. We suggest additional areas of modeling research on this and other threatened species.