Science Spotlight

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  • November 8, 2017

a white-spotted fawn lies in straw as its leg is measured
CDFW Environmental Scientist Brian Ehler measures the hind-foot length on a fawn captured near Medicine Lake for a mule deer study.

four deer are suspended in the air, in safety harnesses, from a red helicopter
CDFW Environmental Scientist Brian Ehler measures the hind-foot length on a fawn captured near Medicine Lake for a mule deer study.

Driving up Interstate 5 through Siskiyou County in northern California, one cannot help but take notice of the looming, majestic land mass of Mount Shasta, the largest volcano in the Cascade system.

In this rugged region of the Golden State, mule deer are an iconic species, valued by recreationists and required by wild carnivores who prey upon them for nourishment. Mule deer are considered a “foundation species” because the large landscapes that are necessary for their survival can also be home to a vast array of other wildlife and plant species. But mule deer populations have dramatically declined in recent decades across many western ranges, and in Siskiyou County, this decrease has prompted researchers from CDFW and the University of California, Santa Cruz to partner on a multi-year effort to investigate the population dynamics of this high-profile species.

Since 2015, 51 adult female mule deer and 37 fawns have been captured in the Mount Shasta region. Biological samples, including blood and parasites, have been collected, physical measurements of body condition and age recorded and telemetry collars attached to each subject. Collars on adult deer provide a GPS location every hour and alert researchers when a mortality occurs. The collars also document movement details, including migration routes and the location of critical winter and reproductive ranges. The fawn collars feature location beacons that allow researchers to monitor both general movements and when a mortality has occurred. Once a mortality alert is sent from a collar, a search of the site and an examination of the carcass ensues to determine if the deer died from predation or other causes, such as disease or malnutrition. The collars have timed releases and are set to drop off the animal after 18 months. Researchers can then reuse the collars after retrieving them by following a GPS signal. This high-tech, high-resolution documentation of deer behavior is vital for prioritizing the conservation value of landscapes so they may be better protected in the future.

With the recent arrival of gray wolves to northeastern California, predators are a key focus of the mule deer project. Understanding the influence this large canid will have on natural prey species begins with establishing baselines of how current predators -- including mountain lions, bears, bobcats and coyotes -- are affecting prey in this region. Mountain lions, which rely on deer as the primary component of their diet, are a major focus of this study. Researchers have captured and affixed five adult mountain lions with GPS telemetry collars, allowing them to track and study rates of predation, feeding patterns and diet composition.

The analysis of fecal DNA combined with new statistical techniques is another way to study population density and composition across broad landscapes. DNA analysis allows researchers to determine the sex and identity of an individual deer, which is used to estimate densities and gender ratios. Researchers are collecting fecal samples throughout the mule deer’s summer range, in the hopes of reliably extrapolating estimates of density and sex ratios across the entire region.

This project, which began in 2015, is scheduled to continue into 2019, as researchers strive to gain further insight into the lives of mule deer and predators across this ecologically complex and breathtakingly beautiful region of the state.

California Department of Fish and Wildlife photos.
Top photo: Mount Shasta in winter.

Categories: Wildlife Research
  • November 1, 2017

a pink, anenome-like flower grows next to a granite rock, under a barely visible, protective wire cage
Lassics lupine grows under protective cages.

a man sits beneath a pine tree on a bed of dry needles, building a small wire cage
Richard Macedo, Habitat Conservation Planning Branch Chief constructs a cage to protect rare, endangered Lassics lupine.

a pink flower with daisy-shaped leaves grows next to a rock, under a wire cage
Lassics lupine grows under protective cages.

Biologists from three government natural resource agencies banded together this summer in an unusual effort to help preserve a species under threat of extinction. They lugged materials to build wire cages into the rough terrain of the remote Lassics mountains near the border of Humboldt and Trinity counties in an effort to protect their target. However, these cages were not built to trap animals; they were constructed to keep animals out.

The barren, green serpentine slopes of Mount Lassic, located in a seldom-visited part of Six Rivers National Forest, are home to one of California’s rarest plants: the Lassics lupine (Lupinus constancei). Lassics lupine is a short plant in the pea family that has bright rose-pink flowers. Only approximately 450 adult Lassics lupine plants were observed during 2017 monitoring of the species conducted by the U.S. Forest Service and the U.S. Fish and Wildlife Service, with assistance from CDFW.

Rodents such as deer mice, squirrels and chipmunks have been eating so many Lassics lupine seeds from the plants that, absent intervention, the species appears to be on the path to extinction within the next 50 years (Kurkjian et al. 2016).

Biologists believe that historical suppression of fires in Six Rivers National Forest beginning in the early 1900s may be indirectly responsible for the encroachment of forest and chaparral into Lassics lupine habitat. Fires that were put out quickly did not grow large enough to reduce encroaching forest, and therefore the forest expanded. With the encroaching vegetation came more seed-eating rodents that depend on vegetation cover for protection from predators.

In 2003, the U.S. Forest Service, U.S. Fish and Wildlife Service and other researchers began an emergency attempt to halt Lassics lupine’s trend towards extinction. Each summer, biologists set off on the laborious hike up Mount Lassic to place cylindrical wire cages over as many flowering Lassics lupine plants as possible. Each cage is anchored to the ground to prevent rodents from squeezing underneath.

The cages are remarkably effective at stopping rodents when properly installed, and they remain on the plants for the duration of the growing season. After Lassics lupine fruits have matured, they often split open suddenly and send seeds flying through the air up to 13 feet away. The cages are then removed each year before the onset of winter snow.

“Protecting endangered species is California’s policy and plants like the Lassics lupine could disappear within our lifetimes,” explained Jeb Bjerke, a biologist with CDFW’s Native Plant Program. “We should do what we can to save these unique plants for the future.”

In 2015, in the midst of an historic drought, an 18,200-acre fire spread through the Lassics, killing many Lassics lupine plants and charring the chaparral vegetation nearby. The fire had little effect on the forest that encroaches into Lassics lupine habitat, but preliminary studies suggest that the fire may have reduced rodent density in the burned chaparral. Despite the apparent reduction in rodent density following the fire, the impact from rodents eating Lassics lupine seeds remains high. Continued caging of Lassics lupine plants therefore remains critical for preventing extinction of the species until a more permanent solution can be implemented, such as significant reduction of encroaching forest. However, such efforts are expensive to plan and implement. As the primary land manager, the U.S. Forest Service would likely be the lead agency in future protective actions.

In 2016, the California Fish and Game Commission received a petition to list Lassics lupine as an endangered species under the California Endangered Species Act and the species was designated a candidate species earlier this year. CDFW is in the process of producing a status review for Lassics lupine that will include a recommendation to the California Fish and Game Commission on whether listing the species is warranted. The legislature directs all state agencies, including CDFW, to seek the conservation of endangered and threatened species.

“I hope that CDFW can continue to partner with the U.S. Forest Service and U.S. Fish and Wildlife Service to protect the Lassics lupine from extinction,” Bjerke said.

For additional information on this subject, please see:

California Department of Fish and Wildlife photos by Jeb Bjerke

Categories: General
  • October 25, 2017

At night, two bats fly low over yellow flowers
California leaf-nosed bats. CDFW photo by retired biologist Andy Moore.

hundreds of bats fly overhead at sunset
Hundreds of bats in flight. ©Dave Feliz, all rights reserved.

a little brown bat with white fungus on nose hangs upside-down in a cave
Little brown bat with white-nose syndrome. US Fish and Wildlife Service photo.

a bat with enormous ears and teeth showing, in flight
Townsend's big-eared bat in flight. National Park Service photo.

The last seven days of October are celebrated each year as Bat Week – a time to learn about the importance of bats in our environment.

Bats are nature’s best pesticide. According to a study by the University of California, Davis, Division of Agriculture and Natural Resources, each of these small mammals eats between half and 100 percent of its own weight in insects every night. Some California species consume as many as 600 insects per hour. Imagine living with all the mosquitoes, flies, midges, moths and agricultural pests that are now consumed by bats!

In monetary terms, the natural pest control that bats provide is extremely valuable to the state’s $54 billion per year agriculture and $450 million timber industries. The bats’ appetite reduces the need for chemical pesticides, reduces crop losses and curtails the spread of crop diseases. According to the US Geological Survey, a recent economic analysis indicated that insect suppression services provided by bats to American agriculture is worth something between $4 billion and $50 billion per year.

California Department of Fish and Wildlife (CDFW) Senior Environmental Scientist Scott Osborn notes the estimate’s wide range makes it hard to know exactly how much money bats save farmers. “But even the low estimate, $4 billion, is an impressive amount,” he said. “Bats are an important part of integrated pest management systems.”

As the wildlife trustee agency in California, CDFW is engaged in several activities to help us understand the conservation status of bats in the state, as well as to address threats to bat populations. At statewide, regional and local scales, our scientists have been deploying acoustic bat detectors to determine the distribution of California’s 25 bat species. When CDFW’s bat acoustic data are combined with data collected by partners at other state and federal agencies, academic researchers and non-governmental organizations, we should have more accurate knowledge of where various bat species occur, as well as their seasonal movements.

White Nose Syndrome (WNS) is now a real threat to California’s bats. WNS is a fungal disease that is estimated to have killed more than 6 million bats in eastern North America. With the discovery of WNS for the first time on the west coast (in Washington state) last year, California is bracing for potentially devastating impacts to our bat populations. CDFW is working with the US Fish and Wildlife Service and other partners to conduct surveillance for the fungus that causes the disease, as well as develop plans to manage the disease when it arrives in California. So far, all of the samples collected from bats and their roosts in California have been free of the fungus, but increased vigilance is necessary to help ensure the disease is detected immediately when it arrives. Special measures to reduce the impact of WNS on hibernating bats may include closing caves and other roosts to visitors, because people can unwittingly spread the fungus on their clothing, shoes and gear. Ultimately, it is hoped that ongoing research into the disease will provide tools to either eliminate or control the fungus, both in the environment and in infected bats.

To learn more about the exciting world of bats and how you can “Go to Bat for Bats!” check out the link opens in new tab or windowBat Week 2017 website.

Top photo: A California bat in a crevice. ©Dave Feliz, all rights reserved.

Categories: General
  • October 19, 2017

The latest issue of CDFW’s scientific journal, California Fish and Game, is now available online.

A bighorn sheep (Ovis canadensis) is featured on the cover of Volume 103, Issue 2. This is to honor the life of well-known wildlife biologist Dick Weaver, who passed away in February 2017 at the age of 91. Known by his friends and peers as “Mr. Bighorn,” Dick devoted much of his adult life to studying and managing bighorn sheep as well as other desert wildlife — and to inspiring and mentoring others who follow in his footsteps.

Not coincidentally, the latest issue also includes the results of a bighorn sheep study. CDFW Environmental Scientist Vernon Bleich and colleagues spent months documenting the mineral content of forage plants used by bighorn sheep at Panamint Range and Old Dad Peak. After measuring the concentrations of 11 minerals in nine plant species, the researchers discovered something surprising: although the same plant species occur in both areas, the mineral contents varied by location. The researchers attribute their findings to climatological differences between the two mountain ranges and to differences in substrate chemistry.

Other published studies in this issue focus on the California red-legged frog (Rana draytonii) and the coho salmon (Oncorhynchus kisutch). Although both species have been extensively studied, these papers document new research methodologies that may improve the accuracy of future efforts to locate red-legged frog egg masses, and to track juvenile coho salmon.

As it has for the past 103 years, California Fish and Game continues to publish high-quality, peer-reviewed science that contributes to the understanding and conservation of California’s wildlife. We look forward to witnessing the contributions of the next installment.

Categories: California Fish and Game Journal
  • October 11, 2017

Four men place a 2,300-gallon plastic tank into a rectangular hole in the southern California desert. Volunteers from the Society for the Conservation of Bighorn Sheep install the second of three 2,300-gallon water tanks to provide water for wildlife in the Southern California desert.

Two men in orange T-shirts place water pipes into a trench in the desertSCBS volunteer Glenn Sudmeier and Steve Marschke install plumbing fixtures for the sheep drinker at the Cady Mountains guzzler project in San Bernardino County.

A metal pipe attached to a rock wall in the desert Pipes bolted into the rocks coming from a catch pond going to the original guzzler installed in the desert.

metal pipes lead to cylindrical tanks in the desert Plumbing pipes leading from the catch ponds to the storage tanks at the 40-year-old Cady # 1.

Two fake rocks and a small solar panel on a post, near real rocky terrain in the southern California desert The completed project: Drinkers are covered by fiberglass simulated rocks that shade the water to slow evaporation and to stop algae growth in the opening of the drinker.

150-foot-long catch field behind fake rocks in the desertEntire scope of the project, with the 150-foot-long catch field in the background that feeds water to the underground tanks.

One of the most elusive species in California is the desert bighorn sheep (Ovis canadensis nelsoni) that live in the dry, desert mountains of southeastern California. Desert bighorn are far from fragile – males are about five feet long and can weigh up to 200 pounds, while the females weigh up to about 150. Despite their size, their keen eyesight and the agility to escape predators up steep rocky slopes, they still face many threats, including disease, human development, expansion and – more recently—a changing climate. Water is critical to their survival in this extreme environment.

The Society for the Conservation of Bighorn Sheep (SCBS), an all-volunteer organization in Southern California, has been working since 1964 for the conservation and management of the desert bighorn sheep. Over the last 40 years, SCBS and CDFW have been installing drinking systems (also called guzzlers) across the sheep’s habitat to help counteract these challenges. Now the populations rely on these water sources to survive and there is a responsibility to keep them functional and maintained.

In September 2017, SCBS rallied the volunteers to install a new drinking system to provide sheep and other animals life-supporting water in the hot summers. The project took place in the desert east of Barstow, and began with the removal and replacement of the very first guzzler ever installed in California.

The old system had two cement catch ponds, each similar to a small swimming pool lined with plastic. The catch ponds collected rain water and funneled it though pipes and valves to three tanks, where it was stored and fed to a small stainless steel drinker box. Due to its age and condition, after being exposed to the desert air and sun for more than 40 years, the system needed constant maintenance, and – more importantly – SCBS members had to haul hundreds of gallons of water across the desert each summer in order to keep the tanks full during the hottest parts of the year.

To improve efficiency and reduce the impact on the habitat, engineers and scientists devised a new approach to the design and installation of the new system. They created a 150-foot-long catch field, laying down three sections of overlapping matting, like tiles on a roof. The mats were then covered with rocks to help it blend into the surrounding area. The mats are made of non-absorbent material that funnels water down a slope where it’s collected and fed into two 2,300-gallon plastic tanks buried in the ground.

SCBS members did all the work to design and engineer the site, dig out the large holes to bury the tanks and install the plumbing and other equipment, including a solar powered satellite telemetry system that will allow scientists to monitor the water levels, ambient temperatures, water flow and other measurements at the remote site.

After four days of morning-to-night labor, the project was completed and the site returned to its near-natural state. Most of the old system was removed with one tank still operating to give the sheep time to find the new water source about 1,000 feet away. The new system is more efficient, requires very little maintenance, and has a higher storage capacity that should eliminate water hauling efforts. The tanks provide enough water for all wildlife in the area, not just the sheep, and they are less visually intrusive from both land and the air, blending well into the desert surroundings.

All this equipment comes at a cost and this construction was paid for with a grant from the CDFW Big Game Management Account (BGMA) that provides money to fund projects that benefit big-game populations and the habitats upon which they depend.

The careful planning and work done will provide a stable and reliable water source for the sheep and other wildlife in this area for decades to come.

To watch volunteers install the new drinking system, watch a video on the CDFW YouTube channel.

Photos of installation courtesy of SCBS. CDFW photos of finished project by Andrew Hughan.

Categories: General
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