Necropsy Training: Studying disease in bighorn sheep

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Dr. Janet Moore (California Animal Health and Food Safety Laboratory – San Bernardino) instructs CDFW field staff in bighorn necropsy techniques.

On Thursday, September 14, 2017, the California Animal Health & Food Safety Laboratory (CAHFS) and the California Department of Fish & Wildlife (CDFW), Wildlife Investigations Laboratory (WIL) hosted a bighorn sheep necropsy course at the CAHFS Diagnostic Laboratory in San Bernardino, California. Assisting with the course were Dr. Peregrine Wolff and wildlife technician Chris Morris from the Nevada Department of Wildlife (NDOW). In attendance were CDFW regional biologists, scientific aides, and veterinarians. The course served as an opportunity for attendees to learn how to recognize, describe, and collect samples from bighorn sheep during field necropsies. It also provided a reminder of how important it is to keep domestic sheep populations separated from free-ranging bighorn populations in order to maintain healthy herds.

After introductory remarks from Dr. Ben Gonzales (CDFW WIL), Dr. Francsisco Uzal (CAHFS) led a discussion on how to describe macroscopic lesions (i.e. distribution, size, shape, demarcation, color, consistency, contour) along with a review of the pathology of a few select domestic and bighorn sheep diseases. Dr. Francisco Carvallo (CAHFS) then expanded upon the main respiratory pathogens of bighorn sheep, which includes lungworms (Protostrongillus spp.), bacteria (e.g. leukotoxin-positive Pasteurellaceae, Mycoplasma ovipneumoniae), and viruses (e.g. respiratory syncytial virus, parainfluenza-3 virus). Following an important review of appropriate PPE (personal protective equipment) to utilize during bighorn sheep necropsies led by Meridith Rhea (CAHFS), Dr. Peregrine Wolff (NDOW) led a discussion on field necropsy techniques and nasal tumors of bighorn sheep to wrap up the morning session.

The afternoon was spent observing a bighorn sheep necropsy demonstration performed by Janet Moore (CAHFS) and Akinyi Nyaoke (CAHFS). Attendees were then given the opportunity to perform their own bighorn sheep necropsies under the guidance of the aforementioned instructors, along with assistance from Karina Fresneda (CAHFS), Patricia Gaffney (CAHFS), Dr. Francsisco Uzal (CAHFS), Dr. Francisco Carvallo (CAHFS), Dr. Peregrine Wolff (NDOW), Chris Morris (NDOW), Dr. Brandon Munk (CDFW WIL), Dr. Ben Gonzales (CDFW WIL) and Dr. Andrew Di Salvo (CDFW WIL).

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Dr. Peregrine Wolff (Nevada Division of Wildlife) demonstrating locating sinus tumors in bighorn.

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Restoring the historic home of the Amargosa vole

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WIL staff and partners assessing the recent habitat restoration efforts. Photo credit: Austin Roy (CDFW)

WIL and our partners at USFWS, UC Davis, CDFW-Region 6, BLM, Amargosa Conservancy, and Shoshone Village are continuing to restore historic vole habitat in Shoshone, CA.  The Amargosa vole was first discovered in Shoshone in the late 1800s, but a myriad of habitat changes resulted in its local extinction from the northern part of its range.

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A recently installed interpretive sign explains the restoration project to visitors and local community members. Photo credit: Deana Clifford (CDFW)

Over the past year non-native vegetation was cleared, soil was contoured and irrigation installed in select areas to more evenly distribute water throughout the fledgling marsh.   The team’s goal was to have a light touch on the land and let the marsh do much of the work regenerating itself.

The beginnings of a marsh capable of becoming vole habitat are appearing!

This restoration project is made possible due to the dedication of local private landowners, volunteers and a community nonprofit.  The effort is funded by a Traditional Section 6 grant and a Partners for Fish and Wildlife grant through the USFWS, funds from CDFW WIL and private matching funds.  Once the marsh is fully restored, we hope to bring voles back to Shoshone and create a new population of voles which will aid in reducing the chance of this species becoming extinct.

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An example of what the marsh looked like during (a) and after (b) initial habitat restoration efforts. Photo credit: Tanya Henderson (Amargosa Conservancy) and Austin Roy (CDFW)

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.

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