Captive-breeding colony of Amargosa voles continues its success

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Captively bred Amargosa voles. Photo credit: Nora Allen

Since 2014, CDFW-WIL has partnered with UC Davis in order to create and maintain a breeding colony of Amargosa voles essential to the recovery of the species.  If interested in learning more about the history and progress of the colony, please read more here.  Below is a video showing a few of the vole pups bred in captivity (Credit: Janet Foley).

Restoring habitat for the endangered Amargosa vole

In the Spring of 2016, CDFW (WIL and Region 6), UC Davis, BLM, USFWS, and many volunteers partnered to restore a key habitat patch utilized by the Amargosa vole. This habitat patch used to sustain the highest density of Amargosa voles in the world, but in 2010 it began to deteriorate due to changes in hydrology. The Amargosa vole team worked diligently to restore the water supply and reinvigorate vegetation growth at the marsh. Learn more about the Amargosa vole project.

New publication describes the prevalence and impacts of toxoplasmosis in Amargosa voles

Recent work from Amanda Poulsen (UC Davis) in partnership with researchers at CDFW-WIL  has been published in the Journal of Wildlife Diseases.  This work examined the prevalence and potential impacts of toxoplasmosis in the wild Amargosa vole population.  To access the paper abstract, click here.

Full reference: Amanda Poulsen, Heather Fritz, Deana L. Clifford, Patricia Conrad, Austin Roy, Elle Glueckert, and Janet Foley (2016) Prevalence and Potential Impact of Toxoplasma gondii on the Endangered Amargosa Vole (Microtus californicus scirpensis), California, USA. Journal of Wildlife Diseases In-Press.

Steps towards restoring an endangered species (Part II)

By Austin Roy (Scientific Aid)

Reintroductions, translocations, and augmentations are methods of restoring or increasing wildlife populations.  These actions require a lot of planning and are often expensive.  These methods involve removing animals from a source population and placing them in another location.  The goal of these efforts are usually to establish a sustainable population where one did not previously exist, provide new individuals to a site with a low population in hopes of increasing the population, and providing new or rare genes to a population that may need genetic rescue, among other reasons.

Healthy habitat at the recipient site that voles were translocated into.

Healthy habitat at the recipient site that voles were translocated into. Photo courtesy of Risa Pesapane

This summer our University of California, Davis and California Department of Fish & Wildlife (WIL) research team conducted a population augmentation for the endangered Amargosa vole (Microtus californicus scirpensis).  Our goal  was to supplement a very small population of voles in one marsh with new individuals and genes from a larger population in another marsh.

A "hard" release of a collared vole at the donor site.

A “hard” release of a collared vole at the source site.

We placed radio collars on 3 voles at the source site, 4 voles that we removed from the source site and relocated to the recipient site, and 3 individuals at the recipient site.  By collaring both relocated voles and resident voles at source site and the recipient site we could monitor how relocated animals utilized the new site and whether or not resident individuals were impacted by the presence of new individuals in their habitat.

Janet Foley (UC Davis Principal Investigator) conducting radio telemetry for collared Amargosa voles.

Janet Foley (UC Davis Co-Principal Investigator) uses and antenna and receiver to listen for the signals of radio- collared Amargosa voles. Photo courtesy of Risa Pesapane.

The data we collected will greatly benefit vole recovery and inform how we conduct future releases.

In addition to the augmentation efforts this summer we also continued to study the population cycles of voles and predators in the area.  These studies allow us to better understand how voles and predators use the area how the predators may be affecting vole populations.  We have also been studying the vegetation and water levels to better understand the needs of the Amargosa vole.  These efforts will help us better understand how to restore and improve vole habitat.

Stephanie Castle, Risa Pesapane, and Amanda Poulsen (UC Davis Graduate Students) conducting a point count for Amargosa vole predators.

Stephanie Castle, Risa Pesapane, and Amanda Poulsen (UC Davis Graduate Students) conduct a point count for Amargosa vole predators.

The research this summer would not have been possible without the support from our partners at the U.S. Bureau of Land Management, U.S. Fish & Wildlife Service, CA Department of Fish & Wildlife (Region 6), Integral Ecology Research Center, U.S. Geological Survey, Shoshone Village, Inyo County Roads Department, and the Amargosa Conservancy.

 

Steps towards restoring an endangered species (Part I)

[*Note from the lab’s Dr. Deana Clifford:  Wev’e been a bit quiet for a while, but not because we’ve disappeared.   We are re happy to start back up again with a 3 part special series updating everyone about our exciting multi-agency/academia/NGO effort to save the critically endangered Amargosa vole. Stay tuned-more posts coming from our activities including voles, fishers, and bighorn sheep!]

By Austin Roy (CDFW WIL Scientific Aid) & Anna Rivera (CDFW Volunteer)

Austin Roy (Scientific Aid) at Site 1 in July 2014.  Notice the degraded bulrush habitat on the right and only moderately healthy bulrush on the left.

Austin Roy at Site 1 in July 2014. Notice the degraded brown bulrush habitat on the right and only moderately healthy bulrush on the left. Photo by Risa Pesapane

Captive breeding can sometimes be an effective conservation method in the toolbox available to wildlife managers. It’s often employed as a last resort when other conservation efforts have not succeeded.  Wild-caught animals are brought into a captive environment and mated for the purpose of increasing the species’ numbers and/or to create an insurance population in case the wild population goes extinct.    Captive breeding programs have helped in recovery efforts for  several endangered species including the California condor, black-footed ferret, island fox, and peregrine falcon.

Our research team from CDFW and UC Davis have been monitoring the population of the endangered Amargosa vole (Microtus californicus scirpensis). In July, we observed that the habitat of the marsh where most remaining voles live was rapidly degrading.  At the same time, vole numbers were rapidly increasing as part of a normal birth pulse cycle.  The shrinking marsh was not going to be able to support the number of voles being born so we consulted with our collaborators in the Amargosa vole working group (the US Fish and Wildlife Service, Bureau of Land Management, US Geological Survey, and UC Berkeley) and brought 20 young voles (that would have likely died in the wild) into captivity to try to establish an insurance population of voles.

Amanda Poulsen (UC Davis Grad Student) placing voles in indoor quarantine cages upon arrival at UC Davis.

Amanda Poulsen (UC Davis Graduate Student) places voles in indoor quarantine cages upon arrival at UC Davis. Photo by Austin Roy

Ten males and 10 females were brought to UC Davis and placed into indoor quarantine in late July 2014.   Individuals underwent disease and genetic testing to decide which individuals would be paired for mating.  After quarantine, voles were placed into pairs for mating.

In October, we successfully weaned our first litter of Amargosa vole pups!  This is the first step to expanding the captive population to the point when animals can begin to be released into the wild to supplement the wild population.  The voles are currently being housed indoors, but we are in the process of creating outdoor pens for the voles where they will experience conditions more closely resembling their natural marsh environment.

While a small step has been made towards the recovery of this endangered species and the path forward remains long, our team remains committed to saving the Amargosa vole.

Click on the links below to read about the Amargosa vole captive breeding program and see more pictures:

Scientists work to save endangered desert mammal – CDFW & UC Davis Press Release

Bouncing Baby Voles Bring New Hope for One of North America’s Most Endangered Mammals – BLM NewsBytes

Throwback Thursday: An Unusual Sea Otter Study

By Tom Batter, WIL Scientific Aid

Happy Throwback Thursday loyal readers!  Today we highlight an article describing an experimental approach by DFG to help curb losses to the abalone industry.  The experiment called for DFG to partner with commercial fisherman to supplement feed to the sea otter populations off the coasts of Monterey and San Luis Obispo counties.  The goal in mind was to make the sea otter’s southern migration unnecessary to help boost abalone production.  Quite an interesting approach that, to this author’s knowledge, was ineffective.  This excerpted page originally appeared in the 1967 November-December issue of Outdoor California.

NovDec67

Wintertime in Vole Country

By Austin Roy – Scientific Aid

Amanda Poulsen, a graduate student from UC Davis and CDFW volunteer, with an Amargosa vole (Microtus californicus scirpensis) after recording demographic data and applying a numbered ear tag.

Amanda Poulsen, a graduate student from UC Davis and CDFW volunteer, with an Amargosa vole (Microtus californicus scirpensis) after recording demographic data and applying a numbered ear tag.

Winter is usually a time to cozy up in front of the fire with a cup of hot chocolate, but winter for the endangered Amargosa vole (Microtus californicus scirpensis) is a totally different story.  These elusive desert rodents do not hibernate like some other mammals.  They work during the cold winter nights (as low as 5F /-15C) and cool days in search of food.  Because of their yearlong activity, the work at WIL doesn’t slow down over winter either.

Researcher looking for predator tracks around known vole habitat near Tecopa, CA.

Greta Wengert Ph.D., a collaborator from the Integral Ecology Research Center, looks for predator tracks around known vole habitat near Tecopa, CA.

Little is known about Amargosa vole behavior and biology.  Most of the information available is derived from the Amargosa vole’s cousin, the California vole (Microtus californicus).  To remedy our lack of knowledge, a team of researchers and volunteers from WIL, UC Davis, and USGS continues to work through the winter to try to learn more about the Amargosa vole.

A track plate box used to record predator tracks

A track plate box used to record predator tracks

Our project involves monitoring the vole population by live-trapping the voles.  This trapping allows for us to assess the health of individual voles, record demographic data (age, sex, weight, etc.), give voles individually marked ear tags, and then release the animals back into their environment.  This type of research allows us to track changes in the population and get an understanding of the geographic range of the vole.  In addition to “hands-on” research, I am also involved with “hands-off” surveillance.  Non-invasive techniques such as looking for vole sign (feces and runways), water sampling, and recording vegetation allow me to gain information about the vole and its habitat while creating as little impact as possible.

A bobcat (Lynx rufus) captured on a trail camera near Tecopa, CA

A bobcat (Lynx rufus) captured on a trail camera near Tecopa, CA

Also, over the winter months I am continuing to gather data on the predators of the Amargosa vole.  Recent findings from USGS suggest that predation might be a limiting factor to the vole’s persistence in its environment.  In response to this finding I began a study to observe and document predators.  I am deploying trail cameras and once a month I conduct point counts to record predator species that utilize vole habitat.  With the help of volunteers, I am also collecting predator feces and pellets.  This allows us to examine the diet of predators and identify which predator species are eating the vole.

The Amargosa vole display recently installed in the Shoshone Museum, in Shoshone, CA.

The Amargosa vole display was recently installed by CDFW and UC Davis in the Shoshone Museum, in Shoshone, CA.

All of this information is well worth the discomfort of working through cold weather.  The data we collect is being applied to the management of the vole  and will aid researchers in understanding how to best help this imperiled animal.  For this reason, we happily bundle up, heat up some tea for our travel mugs, and embrace the weather as we continue to do our best to help the Amargosa vole survive in such an extreme environment.