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.

California to Host Desert Bighorn Council Meeting in 2015

Desert bighorn ewe and lamb

Desert bighorn ewe and lamb
photo by T. Glenner

California will be the host of the 2015 Desert Bighorn Council Meeting. The meeting will take place in Borrego Springs, California in April 2015.  This biennial meeting brings together wildlife biologists, scientists, administrators, managers, and others interested in the welfare of desert bighorn from the seven western states (Texas, New Mexico, Colorado, Arizona, Nevada, Utah and California) to exchange information, present research and take action on matters pertaining to desert bighorn management.

The Council Chair for the 2015 meeting is Dr. Ben Gonzales, Senior Wildlife Veterinarian at the Wildlife Investigations Lab. The Program Chair is Steve Torres, Environmental Program Manager at the Wildlife Investigations Lab. Mark Jorgensen, former Superintendent of Anza Borrego Desert State Park will serve as Local Arrangements Chair.

For more information of the Desert Bighorn Council, please see:

http://www.desertbighorncouncil.org/about.html

Fisher Translocation Project Completes Successful Trapping Effort

by Deana Clifford, wildlife veterinarian

Here’s a post and a photo slide show from our colleagues working on  the Fisher Translocation Project. In this post, Kevin Smith describes our successful efforts to capture, examine and monitor fishers.

The Fisher Translocation Project is led by the CA Dept of Fish and Game (CDFG), the US Fish and Wildlife Service (USFWS), North Carolina State University, and Sierra Pacific Industries. The goal is to translocate fishers into a portion of their historical range in the northern Sierra Nevada. If successful, this project will provide significant benefits to the conservation of fishers in the state.

Photo of DFG Biologist releasing fisher into wild.

CDFG lead for the translocation, Richard Callas and biologist,  Scott Hill release a fisher into the northern Sierras.

Over the past 3 years we have translocated 40 fishers from Northern California to the Stirling Management Area in the northern Sierra Nevada. Although it will take many years to determine if a permanent population will become established, early findings indicate that translocated fishers are successfully reproducing and that fishers born in Stirling are healthy.

The WIL nongame health program provides support to this project by conducting examinations, supervising immobilizations and training field crews. Along with our partners at the Integral Ecology Research Center, and the California Animal Health and Food Safety Lab, CDFG is monitoring the health of these fishers during and after release by determining the cause of any mortalities and conducting testing to determine what diseases fishers and other carnivores are exposed to.

See more information about this project.

A Historical Review of Sierra Nevada Bighorn and the Road to Recovery

By Tom Batter, Wildlife Investigations Lab Scientific Aid

“Bighorn… are extremely wary and cautious animals…His strength and his self-reliance seem to fit him above all other kinds of game to battle with the elements and with his brute foes; he does not care to have the rough ways of his life made smooth; were his choice free his abode would still be the vast and lonely wilderness in which he is found.”

Theodore Roosevelt, Ch. VII A Trip After Mountain Sheep, Hunting Trips of a Ranchman (1885)

While the future President Roosevelt was referencing bighorn sheep (Ovis canadensis) of the North Dakota badlands, his description can be applied just as aptly to the Sierra Nevada bighorn (O. c. sierrae) of California’s east-central boundary.  The rugged mountain peaks and canyons combined with semi-open forest areas provide ideal habitat for these bighorn.

An alert group of Sierra Nevada bighorn.
Image courtesy of John Wehausen & the US Fish & Wildlife Service

Sierra Nevada bighorn sheep (SNBS) are an endangered genetically distinct subspecies of bighorn. They are only found in the mountain range that provides their common name.  Today, these sheep are on the road to recovery, in part thanks to intense monitoring by the Department of Fish and Game’s Sierra Nevada Bighorn Sheep Program (SNBSP) in conjunction with the Sierra Nevada Bighorn Sheep Foundation.  Led by Dr. Tom Stephenson, the program’s goal is to recover sheep numbers to the point that downlisting, or the ultimate goal, delisting, would be warranted.

Recovery activities center around understanding and managing factors that influence population health and the distribution of these bighorn. Among the factors that could be limiting Sierra Nevada bighorn numbers are disease from domestic sheep, predation, weather events and forest succession, which may limit habitat.

Indeed, the preferred haunt of the bighorn is open habitat adjacent to steep and rocky ground.  They are behaviorally and morphologically suited for such an environment.  Bighorn are equipped with keen binocular vision to detect predators from a great distance. Their short legs, hefty frames and low center of gravity provide agility and tremendous balance.  Their hooves are hard on the outer edges and spongy at the center, a unique adaptation that facilitates exceptional grip on rock.  When danger is perceived, the sheep make the most of their physical abilities by retreating into the nearby cliffs and rock walls where few predators can pursue them.

A home fit for a sheep.
(Photo credit T. Batter)

While it is true bighorn are first-rate predator evaders, they have historically had a harder time avoiding another serious threat: humans.

It was during the mid-1800s that Sierra bighorn sheep numbers began to decline.  Throughout this time California experienced a population boom due to the discovery of gold.  Once the gold rush craze eased up, settlers that remained in the area turned to ranching.  Domestic sheep and cattle began grazing the Sierras, increasing forage competition.  At the beginning of the 20th century, bighorn numbers were down to the thousands.

Domestic sheep graze in the Sierras.
Image courtesy of USDA-Forest Service

Grazing sheep and cattle on western federal lands became the subject of a sizzling congressional debate.  President Roosevelt was neither a fan of forest grazing nor of domestic sheep themselves – he described them as “the most foolish of all tame animals” and referred to flocks as “fleecy idiots.”  A quarrel over sheep grazing created a rift between legendary conservationists John Muir and Gifford Pinchot.  Pinchot assured Muir he was against sheep grazing in forest reserves.  Muir furiously confronted Pinchot over quotes in a Seattle newspaper that suggested otherwise. Disagreement between wool growers and preservationists was high, which ultimately led to grazing regulations and agreements.

While forage competition and over-hunting played a role in bighorn population decline, today one of the most critical threats to Sierra Nevada bighorn recovery is disease transmission from domestic sheep .  Domestic sheep are carriers of pathogens that cause respiratory disease in wild sheep.  While domestic sheep remain unaffected, bighorn that are exposed have no defense against these pathogens and are therefore extremely susceptible to disease and ultimately death.

Recent pneumonia related all-age mortality events have resulted in the deaths of hundreds of bighorn in the Rocky Mountain West. Research implicates a particularly difficult-to-diagnose bacteria,  Mycoplasma ovipneumoniae, in initiating many of these outbreaks.  While Mycoplasma ovipneumoniae is commonly found in healthy domestic sheep, years of extensive testing has demonstrated that this bacteria is absent from Sierra Nevada bighorn herds.  This absence certainly results in healthy bighorn, but it also means that the wild herds will be very susceptible to respiratory disease if they are exposed to the organism.  Once exposed, the typical sheep habit of nose-to-nose greetings can result in the unstoppable transmission of the organism within the herd.  Extensive ram movements can then spread the disease to other populations.  Historically, these disease outbreaks have resulted in initial all-age mortality followed by years of high lamb mortality, both of which will delay or prevent the recovery of the Sierra Nevada bighorn sheep.

By the mid-1990s, an estimated 100 bighorn remained in the Sierra Nevada region.  Such low numbers expedited the process of listing the sheep as endangered; in 2000, the Sierra Nevada bighorn sheep became the first federally endangered species listed in the 21st century.

Bighorn sheep have heavy ridges which run across the horns, formed each winter. It is possible to age a sheep based on the number of deep grooves. This ram I am supporting was about 7 years old and weighed in near 240 lbs! (Photo credit T. Batter)

This is where Dr. Tom Stephenson, SNBS program personnel, and the Wildlife Investigations Lab (WIL) enter the equation.  Once every fall and spring, Sierra Nevada bighorn are captured and fitted with radio and GPS collars.  Sheep are captured from a helicopter using a hand held net gun (services rendered by Leading Edge Aviation).  The captured sheep are hobbled, blindfolded, and securely fastened into a carrier.  The sheep are then airlifted to a base camp and monitored by processing teams where their safety is the top priority.  In base camp, WIL provides essential equipment, expertise and training in wildlife restraint and humane care, as well as veterinary medical care of injuries or medical problems that occur during the capture

WIL veterinarian Dr. Ben Gonzales lends his expertise in monitoring the health of each sheep that is flown in.  Crew members are trained to closely monitor the bighorn and to collect appropriate blood and nasal samples to evaluate population health.  After the team fits the collars and applies an ear tag, the bighorn is then airlifted back to the capture site where it rejoins the flock.  The collared sheep will then begin to accumulate data that is imperative to their recovery success.

The radio and GPS collars are very useful and important tools in the recovery process for these animals.  Movement patterns, habitat use, survival and causes of mortality can all be examined.

Radio and GPS collars are securely fastened on a ram.
(Photo credit T. Batter)

Furthermore, human recreational impact on the bighorns can be assessed, as well as the grazing overlap between bighorn and domestic sheep.  The collected data will allow for science-based management decisions to be made in order to ensure the survival of Sierra Nevada bighorn.  So far, efforts have helped increase Sierra Nevada bighorn numbers to over 400 individuals.

The Leading Edge Aviation crew as they airlift two processed sheep back to their flock. (Photo credit Trista Welsh)

President Roosevelt went on to describe bighorn sheep as having “…no animal in the world his superior in climbing…”  With successful recovery efforts, the SNBS Program and the Sierra Nevada Bighorn Sheep Foundation in partnership with the Wildlife Investigations Laboratory will help guarantee that these rare bighorns remain the ultimate mountain climbers well into the future.

SNBS ewe is collared, tagged, and ready to return! (Photo credit T. Welsh)