Julia D Owen-Ramos; University of California, Davis;; Cate Brown Quinn, Ellie C. Bolas, Dirk H. Van Vuren, Ben N. Sacks

Island species have long been considered an important tool for understanding speciation and to investigate evolutionary forces driving DNA sequence evolution. The Island spotted skunk (Spilogale gracilis amphiala) is an endemic insular carnivore found on two of the Channel Islands off the coast of southern California: Santa Rosa Island and Santa Cruz Island. Limited study of morphology found little differentiation between the island spotted skunks and their mainland counterpart, the western spotted skunk (S. gracilis microrhina, S. gracilis phenax), fueling an idea that spotted skunks arrived on the Channel Islands in the past two centuries. However, genetic studies using microsatellites and mitochondrial DNA found significant differences among the two island populations and mainland populations, suggesting a longer evolutionary history of spotted skunks on the islands. Still, the degree to which island spotted skunks are diverged from one another and from their mainland relative remain unclear. To further investigate the evolutionary history of island spotted skunks, we sequenced whole genomes of skunks from Santa Cruz Island, Santa Rosa Island, and the California mainland. Our results support the antiquity of island spotted skunks, showing high genomic differentiation between all three populations, lower diversity in island populations, and increased inbreeding in island populations.

Mammals IV: Mustelids   Student Paper InPerson Presentation



Tanya Diamond; Pathways for Wildlife;; Ahiga Sandoval, Jessie Quinn, Ken Hickman, Yiwei Wang, Dan Wenny, Karine Tokatlian

American badger (Taxidea taxus) and western burrowing owl (Athene cunicularia hypugaea) occur in the San Francisco peninsula however information about their population status and distribution was limited.  The Midpeninsula Regional Open Space District (District) funded a study of both species in order to best manage them and their habitats within District properties, and to contribute to regional species conservation.  Study methods included GIS analysis to create habitat suitability models and a badger linkage model, field surveys and camera trapping to ground truth models, and genetic analysis of badger hair.  More than half (58%) of all collected badger observations were found within six District properties clustered along Skyline Ridge/Hwy 35.  Model results show that badger habitat in the peninsula is heavily fragmented by natural and anthropogenic factors, and their pathways of movement are narrowly restricted which highlights the importance of maintaining landscape permeability for this wide ranging species.  Three primary badger movement linkages were identified: 1) a central network of habitat connections between District properties along Skyline Ridge/Hwy 35, 2) a coastal linkage running from north of San Mateo down to Santa Cruz, and 3) an eastern linkage running from Skyline Ridge/Hwy 35 to Coyote Valley.  The coastal linkage provides more suitable badger habitat compared to the eastern linkage and may be the only viable pathway for badgers to reach the central District population.  Results suggest that moderate grass management is beneficial for both species.  Results supported anecdotal knowledge that burrowing owls winter in some District properties but do not breed there.  Twenty-five individual badgers were identified using genetic analysis, eleven of which were collected within District properties, however sample amplification rates were not successful enough to calculate a badger population size in the peninsula.  Results suggest that badgers on the peninsula appear to be an isolated population with some degree of inbreeding, and as less genetically diverse than populations to the north and south.  The District is pursuing opportunities to continue genetic sampling achieve a badger population size metric.  Results inform an array of future management opportunities include maintaining grassland connectivity, identifying and enhancing bottlenecks along linkages (wildlife friendly culverts, vegetation management), using artificial burrows to enhance existing wintering owl habitat, acquiring properties to strategically support grassland connectivity, and develop regional support for species conservation and listing consideration.

Mammals IV: Mustelids  Zoom Presentation



Corbin C Kuntze; University of Wisconsin - Madison;; M. Zachariah Peery, Rebecca E. Green, Kathryn L. Purcell, Jonathan N. Pauli

Rapid environmental changes – in climate, land use, and biotic interactions – are accelerating species extinctions and extirpations globally. Identifying the drivers that threaten populations is essential for conservation yet can be difficult given the variable nature of an organism’s response to biotic and abiotic stressors. We analyzed a 13-year monitoring dataset to explore the demographic responses of fishers (Pekania pennanti) to rapid environmental change in the southern Sierra Nevada, California, USA. Fisher survival was sensitive to both biotic and abiotic factors, although the strength and direction of these effects were ultimately mediated by age and sex. Specifically, male survival was lower among young individuals and decreased with increasing temperatures, basal area of hardwoods, and fungi consumption. Female survival was resilient to age effects and diet yet increased with greater forest heterogeneity and decreased with increasing temperatures and snow depth. Our findings illustrate the importance of disentangling the effects of both intrinsic and extrinsic factors on survival, especially among species with distinct sexual or ontogenetic differences. As global drivers of environmental change intensify in strength and frequency, understanding these complex relationships will allow practitioners to best manage for population persistence of fishers and habitat resilience concurrently.

Mammals IV: Mustelids   Student Paper InPerson Presentation



Jody M Tucker; U.S. Forest Service;; Sky Alibhai, Remi Murdoch, Ryan Lekivetz, Caleb King

Footprint identification technique (FIT) is an emerging non-invasive tool in wildlife conservation that has been adapted for a wide variety of species. FIT enables classification of footprints using a geometric profile generated through computer software with a simple graphical user interface.  Here we report the development of novel application of footprint identification technique (FIT) for species discrimination for fisher (Pekania pennanti) and marten (Martes caurina), and sex-ID for fisher.  We developed FIT using footprint images collected from free-ranging animals at track plate stations that were identified to individual and sex via genotyping of non-invasive genetic samples.  We developed a reference dataset of 165 marten tracks and 267 fisher tracks (27 females, 34 males).  Geometric profiles for each track were extracted using a specialized FIT add-in developed for fisher in JMP data visualization software. We used a linear discriminant analysis to analyze these geometric profiles and create discriminant functions for species and sex ID.  Classification accuracy for both species and sex ID was >90%.  FIT provides a promising new tool for fisher research and monitoring by providing a simple and cost-effective method for non-invasive species or sex identification.

Mammals IV: Mustelids  Zoom Presentation



Katie Moriarty; Senior Research Scientist;; Heather Rustigian-Romsos, David S. Green, Rebecca Green, Brent R. Barry, G. Brad Smith, Jody Tucker, John D. Bailey, Sean Matthews, Matthew S. Delheimer

California has experienced unprecedented wildfire activity in recent years, as half of the twenty largest fires in the state's recorded history occurred during 2020-2021. Large and severe wildfires have substantial potential to degrade or effectively eliminate, for the near future, habitat of forest-dependent species such as martens or fishers. For instance, >33% of predicted habitat for the endangered southern Sierra fisher population burned in the past 2 years and >55% since 2012. We describe conditions in the Sierra Nevada with >10 years of animal demographic data in 2 locations. In the northern Sierra, we estimated the influence of fire on predicted habitat and connectivity for marten. We created predicted habitat models from extensive location data and spatially optimized variables. We evaluated models using cross validation and independent data, then created a resistance surface (negative exponential predicted habitat quality). The Dixie fire burned 45% of marten predicted habitat cores and 38% of corridors, 24% of which were at moderate or high severity. In both study areas we ran new simulations following fire, assuming high resistance in moderate/high severity burned patches to identify areas for optimized restoration planning. We conclude with creative ideas and possibilities for maintaining forest dependent species in landscapes with prior and ongoing megafires. 

Mammals IV: Mustelids  InPerson Presentation



Rebecca E Green; NPS - Sequoia-Kings Canyon NP;; Jody Tucker, Sarah Stock, Tyler Coleman, Greta Wengert, Tessa Smith, Emerson Paton, Chloe Burt, Leah Kerschner, Stephanie Eyes, Esther Burkett

The landscape in the southern Sierra Nevada has undergone dramatic change over the last decade, including a severe drought starting in 2012, extensive conifer mortality beginning in 2015, and a series of increasingly large and intense wildfires including (from north to south) the Ferguson Fire (2018) in Yosemite National Park, the Rough Fire (2015) in the Sierra National Forest, and the KNP Complex Fire (2021) in Sequoia-Kings Canyon National Park. Living in the midst of this changing landscape are fishers (Pekania pennanti) and other wildlife species that depend on features of mature forest, including dense canopy cover, large diameter trees, and microsites suitable for resting and reproduction (e.g., large cavities, hollow logs). Beginning in summer 2021, we used a combination of remote cameras and GPS collars to identify where fishers continue to occur, which patches of older forest (“forest refugia”) they are using, and how they navigate in or around recent fire footprints to remaining green forest (“linkage habitat”). We report the broad findings of this multi-agency endeavor (2021-2022) for the Merced River study area (Yosemite NP, Stanislaus NF, Sierra NF) and the Kings-Kaweah Rivers study area (Sequoia-Kings Canyon NP, Sequoia NM/NF) and implications for conservation.

Mammals IV: Mustelids  InPerson Presentation