Fisher and Marten in California

WildTrack has been partnering with Dr Jody Tucker of the The U.S. Forest Service’s Sierra Nevada Carnivore monitoring program .  Jody studies fisher (Pekania pennanti), Pacific marten (Martes caurina), and other associated carnivore species to assess population changes over time in occupancy, geographic distribution, genetic diversity and connectivity.  Both species are considered species of conservation concern by federal and state agencies and fisher has been proposed for federal listing under the Endangered Species Act.  Conservation concerns are particularly acute for the southern Sierra Nevada fisher population’s due to its small population size (<500 individuals), geographic isolation, low genetic diversity, habitat at high risk of wildfire, and recent widespread change in forest conditions due to drought and tree mortality.

Smearing lure on a tree

Large scale monitoring of such rare and elusive species is very difficult. Trying to reliably detect a handful of fisher or marten across hundreds of thousands of acres in steep mountainous terrain is physically demanding, time consuming and logistically complicated.  Such landscape scale monitoring using capture based methods is cost prohibitive so we rely on a variety of non-invasive techniques to study these populations:  remote sensor camera traps, track plates, and hair snares.

Fisher range in the USA

The Fisher

While the use of cameras and hair snares are now ubiquitous in wildlife research, the use of track plates has become less common in recent years.  Track plates are involve the use of a plate covered with a substance used as ‘ink’ to collect animal tracks (i.e. chalk, soot, printer ink) usually baited to draw an animal across the track plate surface. For our study we use a layer of carbon soot applied with a torch to a metal plate.  Between the soot and the bait is a piece of white contact paper to collect tracks – this baited plate placed into a box enclosure.

Sierra Nevada landscape

Fisher tracks on paper

Traditionally, tracks have solely been used for species detection with individual or sex determination only possible through genetic analysis at stations where a high quality hair sample is obtained.  Recently, we have been collaborating with Wild Track to determine if FIT technology can be applied to track plate data to identify individuals. This technology would greatly increase the capacity to identify individuals and provide expand analytical options for monitoring these species.  Additionally, as track sheets have been systematically archived for decades for fisher and marten in California, FIT technology could also potentially provide individual identification for this historical track collection.

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