Proposed listing of the Pacific marten

A petition was submitted to the U.S. Fish and Wildlife Service (the Service) on September 28, 2010, by the Center for Biological Diversity and the Environmental Protection Information Center (EPIC), to list the Humboldt marten (Martes caurina humboldtensis) as threatened under the Endangered Species Act (ESA). On January 12, 2012, a 90-day finding was published by the Service indicating that listing may be warranted (77 Fed. Reg. 1900) and, on June 23, 2014, the Service published notice of intent to conduct a 12-month finding (79 Fed. Reg. 35509). On April 7, 2015, the Service published a "not-warranted" finding (80 Fed. Reg. 18742), analyzing the coastal Distinct Population Segment of Pacific marten for consideration instead of the subspecies due to insufficient genetic evidence. On March 28, 2017, a district court in northern California remanded for reconsideration the "not-warranted" decision.

Based on its assessment of the resiliency, redundancy and representation of extant populations, the Service issued a proposed rule on October 9, 2018, for the coastal Distinct Population Segment of the Pacific marten in northern California and Oregon to be classified as Threatened under the ESA (86 Fed. Reg. 50574–50582). The Service has provided a Species Status Assessment (SSA) and cited two primary threats in their decision to propose federal listing status for the coastal DPS of Pacific marten: Factor A is a decrease in connectivity among populations, and Factor B is habitat conversion from that suitable for Pacific martens to that suitable for generalist predators and competitors of Pacific marten. Vegetation management, wildfire, and climate change are cited as the primary mechanisms related to Factor A and B threats.

In December 2018, NCASI submitted comments to the Service relative to the proposed listing of Pacific marten. The summary of those comments follows:

Within this document, we provide both technical and editorial comments for consideration. Our technical comments focus on four points: (1) the population estimate for martens in the Northern California population seems unrealistically low and we provide four lines of evidence for consideration in this regard, (2) assumptions regarding lack of connectivity in southern Oregon may be incorrect based on additional (and new) location data, (3) the current habitat model requires increased transparency and is not appropriate for extrapolation across the species range, and (4) the assumption of increased predation risk is unfounded based on the provided information. Additional information would be necessary to provide confident statements as described in the proposed rule.

Contact Dr. Katie Moriarty ( for more information.