Density and population viability of coastal marten: a rare and geographically isolated small carnivore

Mark A Linnell; Katie Moriarty; David S Green; Taal Levi

doi:10.7717/peerj.4530

Density and population viability of coastal marten: a rare and geographically isolated small carnivore

PeerJ. 2018 Apr 4:6:e4530. doi: 10.7717/peerj.4530. eCollection 2018.

Authors

Mark A Linnell^#¹, Katie Moriarty^#², David S Green³, Taal Levi⁴

Affiliations

¹ Department of Forest Engineering, Resources, and Management, Oregon State University, Corvallis, OR, United States of America.
² Pacific Northwest Research Station, United States of America Department of Agriculture, Forest Service, Olympia, WA, United States of America.
³ Institute for Natural Resources, Oregon State University, Corvallis, OR, United States of America.
⁴ Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, United States of America.

^# Contributed equally.

Abstract

Pacific martens (Martes caurina humboldtensis) in coastal forests of Oregon and northern California in the United States are rare and geographically isolated, prompting a petition for listing under the Endangered Species Act. If listed, regulations have the potential to influence land-use decisions on public and private lands, but no estimates of population size, density, or viability of remnant marten populations are available for evaluating their conservation status. We used GPS and VHF telemetry and spatial mark-resight to estimate home ranges, density, and population size of Pacific martens in the Oregon Dunes National Recreation Area, central coast Oregon, USA. We then estimated population viability at differing levels of human-caused mortality (e.g., vehicle mortality). Marten home ranges were small on average (females = 0.8 km², males 1.5 km²) and density (1.13 martens/1 km²) was the highest reported for North American populations (M. caurina, M. americana). We estimated 71 adult martens (95% CRI [41-87]) across two subpopulations separated by a large barrier (Umpqua River). Using population viability analysis, extinction risk for a subpopulation of 30 martens, approximately the size of the subpopulation south of the Umpqua River, ranged from 32% to 99% with two or three annual human-caused mortalities within 30 years. Absent population expansion, limiting human-caused mortalities will likely have the greatest conservation impact.

Keywords: Density; Marten; Martes americana; Martes caurina; Population viability analysis; Spatial mark-resight.

Grants and funding

Survey efforts were funded by the USDA Forest Service Pacific Northwest Research Station, Siuslaw National Forest, and US Fish and Wildlife Service’s Portland Office. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.