Recent accomplishments of CDFW's scientific community
Five agencies in two states recently partnered to help a tiny population of Greater Sage Grouse avoid extinction along the California-Nevada border. Biologists from the California Department of Fish and Wildlife, the U.S. Fish and Wildlife Service, Los Angeles Department of Water and Power, the Bureau of Land Management and the U.S. Geological Survey are working together in this first-of-its kind study. On April 22, the bi-state team of scientists captured, inseminated, transported and released 17 of these female upland birds to a new habitat where they will hopefully flourish and repopulate. Eight male birds were also transported to Bodie Hills as part of the study.
The birds were captured near Bodie and moved to Parker Meadows, about 30 miles south. CDFW scientists have been tracking the number of Greater Sage Grouse in Parker Meadows for years, and it was evident that human intervention would be necessary to keep the group alive. Between 2002 and 2010, the number of males had dropped from about 17 to only four, and CDFW estimated that the entire population had a 70 percent chance of going extinct in the next five years.
Translocation was chosen as the best option to save them, as it would not only boost the number of birds in the area, but also immediately widen the gene pool.
The birds were captured at night, measured and radio-collared. The hens were also artificially inseminated with sperm from the males in the Bodie population before being transported and released to integrate into their new home. (Watch video of the capture, insemination and release.)
Although biologists from the U.S. Geological Survey will be doing most of the hands-on work with the birds, CDFW biologists played an important role as well. Environmental Specialist Tim Taylor worked for months to obtain the proper land access permissions and assess the habitat near Bodie. Taylor identified several potential problems (including conifers, where raptors would likely perch while in search of prey, and barbed wire fencing) that needed to be removed prior to the relocation. And Senior Environmental Scientist Scott Gardner, in Sacramento, was instrumental in securing grant funding – without which, this partnership project would not have been possible.
“It’s a long term thing – it’s going to take about five years to get results we are hoping for,” Taylor said. “But we’ve got a great crew and I’m confident we’re going to have success and keep that little population going.”
Read more about the Greater Sage Grouse study.
Photos by Dan Hottle/USFWS
This summer marked the end of an incredible journey for four dozen of California’s designated state freshwater fish, the golden trout, as they returned home after 10 months away. The fish traveled more than 500 miles in tanks and buckets, by hand and by mule, en route to their native waters 9,000 feet up in the Sierra Nevada range.
The journey began last fall after CDFW scientists observed that ongoing drought conditions were severely impacting the rare trout’s mountainous habitat. A decision was made to rescue 52 fish – a representative population that could repopulate the stream and save the species if drought conditions worsened.
Golden trout are one of California’s most iconic trout species. They are native to only two stream systems in the southeast Sierra Nevada – Golden Trout Creek, and the South Fork Kern River in Tulare County. Volcanic Creek, which is home to the rescued fish, connects with Golden Trout Creek during runoff and high-water level years.
The journey began in September 2016, when fisheries biologists made the two-day trek into the mountains to gather the trout. The captured fish were transported to the American River Trout Hatchery near Sacramento, where technicians monitored them, often around the clock. After nine months at the hatchery, the fish were ready to start the long trek back to their home waters. Crew members transferred the fish from the hatchery to a fish tanker truck and hauled them more than seven hours overnight to the trailhead at an elevation of 10,000 feet in the southern Sierra.
The crew met up with a CDFW team that would escort the fish on horseback, 16 miles into the Inyo National Forest. Federal laws forbids motorized vehicles on wilderness land, which left the team no option but to transport the fish by mule train in fish cans.
The operation took tremendous teamwork from multiple divisions in CDFW and the National Forest Service. Ultimately, the CDFW team successfully returned 48 fish to their natural element. Four died in captivity over the winter. CDFW officials consider that a normal mortality rate. Scientists remain optimistic that these iconic fish will continue to thrive and perhaps even be on-track for a brighter future.
See related VIDEO.
Pronghorn antelope (Antilocapra americana) were once one of the most numerous large mammals in California, with populations estimated to have been as high as 500,000 prior to the Gold Rush era. In the mid-1800s, pronghorn were nearly extirpated by market-shooting to feed California’s rapidly expanding human population.
The remaining population of pronghorn has long been understudied. Prior data collected on the species have been limited to herd counts and habitat selection. In recent years, there has been growing concern over pronghorn populations, particularly in northeastern California. During the harsh winter of 1992, the number of pronghorn dropped almost 50 percent to an estimated 5,000 individuals. The northeastern portion of the state currently supports a population of approximately 4,500 animals that occur primarily in Modoc, Lassen, Siskiyou and Shasta counties and has been fairly stable, with slow declines, since about 2000. The herd’s inability to rebound has prompted scientists to try to understand the specific conditions leading to the declines.
In 2016 the Institute for Wildlife Studies (IWS) completed a two-year study, with funding from CDFW’s Big Game Management Account, which explored aspects of the pronghorn population on the Modoc Plateau. The study involved 48 does (adult females) and 42 fawns that were radio-collared and followed until their deaths or the study’s end. The researcher’s objectives were to learn more about the pronghorn use of habitat, aspects of their reproduction and factors affecting survival of does and fawns.
The researchers found that for most of the year, pronghorn used open areas with less shrubby and more herbaceous vegetation within their sagebrush-steppe habitats. But during fawning, when does need to hide their young, they shifted to spending more time in areas with greater densities of shrubs and juniper trees. The annual survival rate for does in the study was 69 percent, which is low compared to other pronghorn populations. Mountain lions accounted for 80 percent of predator-related mortalities, most of which occurred during and just after the peak birthing period when does are most vulnerable. Fawn survival averaged 44 percent, a higher-than-typical figure, with unknown causes (37.5 percent) or suspected coyote predation (21 percent) accounting for most fawn mortalities.
The adults’ increased use of shrubby areas and conifer woodlands during fawning suggests an important factor in the population’s continued decline. Juniper woodlands have been encroaching on the sagebrush-steppe habitat in the Modoc Plateau for decades, and these juniper trees provide areas of concealment for ambush predators such as mountain lions. Most ungulate studies demonstrate that adult survival plays a more critical role in population stability than juvenile survival. CDFW may be able to reduce adult pronghorn mortality through habitat restoration – the removal of encroaching junipers could help to reduce predations by lions, and potentially increase the Modoc pronghorn population.
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