Science Spotlight

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  • December 9, 2021
Bird on a tree branch

California is home to more native animal and plant species than any other state in the nation. It also hosts the most endemic species—species that occur nowhere else in the world. However, our incredibly diverse native wildlife is facing an intensifying array of stressors stemming from human activity: habitat loss, new land uses like cannabis cultivation, invasive species, wildfires, drought and so many others. Wildlife managers can mitigate these threats through actions like conserving and restoring habitat, building relationships with private landowners and managing ecosystems for resilience to wildfire and climate change. But, to effectively target management actions, managers need to have high-quality information on wildlife populations across the state.

In two studies recently published in the California Fish and Wildlife Journal, Vol. 107-2 (PDF), researchers with CDFW’s Cannabis Program and Wildlife Diversity Program focused on this need for effective wildlife data collection.

One study focused on monitoring small terrestrial vertebrates, like small mammals, reptiles and amphibians. Traditionally, researchers have monitored these species through live-trapping and visual encounter surveys. But such time-intensive methods are not always feasible. Recently developed methods that use automatic cameras are one alternative. To determine how well cameras perform compared to more traditional methods, CDFW researchers tested two methods alongside each other: 1) visual encounter surveys, where they searched for reptiles and amphibians in a study area, and 2) camera traps, which combined small strips of fencing with close-focus cameras pointed at the ground. They found that the camera system detected far more species of small animals compared to the traditional surveys.

In a second study, researchers compared different methods for monitoring birds. Traditionally, researchers have used point counts, where trained observers identify every bird they hear or see at a location. Researchers are also increasingly using acoustic devices to automatically record bird sounds. Recently, machine learning tools have enabled computers to identify bird sounds from these recordings, allowing people to indirectly identify birds while saving much time and effort. In their study, the CDFW researchers found that low-cost recorders performed comparably to expensive ones, and that a machine learning tool accurately identified high numbers of bird species from the recordings.

The researchers will apply what they have learned and shared to a new statewide monitoring effort, which is being developed by CDFW’s Cannabis Program. These advancements will enable a more efficient wildlife monitoring effort that saves money and time. And most importantly, with the information gained from improved monitoring, CDFW staff and other wildlife managers will be able to make more informed decisions to help our native California wildlife cope with current and future challenges.

Categories: California Fish and Game Journal, General, Science Spotlight
  • November 12, 2021
journal cover featuring mouse balanced atop grain stock

Since being signed into law in 1970, the California Endangered Species Act, or CESA, has proved to be a landmark law in a history of progressive wildlife conservation in California. It has been key in helping to stem the tide of species extinctions, raise public awareness about the plight of wildlife, and underscore the need to balance species conservation with economic development. CDFW is responsible for safeguarding the hundreds of CESA-listed species, and a key part of this mission is supporting and elevating the important research being conducted on these imperiled plants and animals.

The 2021 Special Issue of the California Fish and Wildlife Journal titled “The California Endangered Species Act: Successes and Challenges” contains a comprehensive collection of articles about the research, management and conservation of threatened and endangered species. At 473 pages, this is the largest Journal issue ever published! It includes 16 full research articles, five research notes, two review papers and four essays, altogether covering 25 species. Authors include CDFW staff, academic researchers, non-profit organizations and other conservation entities. Download the entire issue (PDF) or individual articles.

Topics covered in the issue include range expansions, new methods for species identification in the field and lab, reviews of habitat use and spatial occurrence patterns throughout California, results of management actions, benefits of long-term monitoring programs and planning strategies for conservation and recovery actions. The issue starts with a CESA Policy and Regulations section and follows with eight sections organized by taxa. Photos at the beginning of each section showcase California’s amazing biodiversity. For those new to CESA, an overview of the listing process is provided both in a detailed article and a simplified flowchart.

Article highlights include:

Amargosa Niterwort

Plants make up 158 of the 316 species currently listed under CESA. In this issue, Amargosa niterwort (Nitrophila mohavensis) takes the spotlight when authors share the value of a 10-year monitoring program for this alkali wetland plant, which occupies a total area less than 20 km2 in the northern Mojave Desert. Collaborative monitoring has resulted in a better understanding of the species, including phenology and abundance trends. This information could support conservation actions in response to threats such as groundwater alteration and off-highway vehicle impacts. For more details, see the article titled “Status of the Amargosa niterwort (Amaranthaceae) in California and Nevada.”

Bumble Bee Protection

In the article “A conservation conundrum: protecting bumble bees under the California Endangered Species Act,” authors Richard Hatfield and Sarina Jepson of the Xerces Society for Invertebrate Conservation present their view of the history and recent context of listing invertebrates under CESA. The authors argue that population declines driven by factors including climate change, insecticides and habitat loss have led to thirty percent of California’s bumblebee species facing extinction risk. In light of this, the Xerces Society and others have led a recent push to provide formal protections for several species of bumblebee. The article provides the authors’ overview of their 2018 petition to protect four imperiled bumblebee species under CESA and the subsequent legal complications that have unfolded.

California Tiger Salamander

“Use of atypical aquatic breeding habitat by the California Tiger Salamander” provides insight into this endangered species’ ability to reproduce outside of its historically associated habitat. Typically thought to reproduce only in vernal pools, researchers observed California tiger salamanders breeding in cattle stock ponds, intermittent creeks and rain-filled excavated depressions. Further investigation is needed to determine if these atypical breeding sites result in any reproductive success, as some have limited hydroperiods that may not be conducive to California tiger salamander metamorphosis. However, this study provides insight for the potential role of reproductive plasticity in the face of vernal pool habitat loss. For development projects within the range of the California tiger salamander, this study identifies additional habitat features that should be assessed when identifying and addressing potential impacts to this listed species.

We would like to thank the CDFW editorial staff for their hard work on this special issue. We also want to thank and acknowledge the researchers and authors of the articles, whose hard work to understand these imperiled species is helping bring them closer to recovery. The California Fish and Wildlife scientific journal has published high-quality, peer-reviewed science that contributes to the understanding and conservation of California’s wildlife for more than 100 years. We look forward to the continued contributions in the next decade to come.

Categories: California Fish and Game Journal, Science Spotlight
  • September 17, 2021
burned landscape after low severity fire

As Californians continue to face devastating wildfires, researchers are lending their expertise by producing data to inform fire policy.

CDFW contributed an article to a recent special-edition journal featuring fire studies from around the world. CDFW’s paper shows that a mix of fire intensities, and low severity fires in particular, promote a diversity of forest carnivores like bears, fishers and bobcats. The results of the study support the value of prescribed burning in advancing ecological and societal objectives including wildlife diversity and human health and safety.

“Wildfire is a natural part of the landscape, and we probably can’t stop it,” said the paper’s lead author, CDFW Senior Environmental Scientist Dr. Brett Furnas. “But prescribed burning is a tool we have to mimic low severity fires, which are less destructive. It’s a win-win because low severity fires have the added benefit of improving biodiversity.”

Dr. Furnas and his team conducted the research by analyzing data from 1,500 camera traps that have been placed by scientists in Northern California forests since 2009.

“We pulled together a large data set and compared the occurrence of 15 species of forest carnivores — including bears, fishers and bobcats — to the fire history of the landscape during that time period. The study shows our forest carnivores are well-adapted to low severity fires,” said Furnas.

Unlike high intensity fires which tend to eradicate all trees in a given area, low intensity fires tend to thin out forests and burn mostly the understory. Prescribed burning mimics the effects of low intensity fires which are associated with ecological benefits. Other research has shown that mixed intensity fires in California have ecological benefits for birds, bees and plants.

“The goal of the study was to use science to help inform conservation decisions,” said Furnas. “The science can help policy makers decide the best course of action and how to balance the needs of the state.”

Media Contact:
Ken Paglia, CDFW Communications, (916) 825-7120

Categories: Science Spotlight, Wildlife Research
  • June 22, 2021
monarch butterfly on a milkweed leaf

A male adult monarch on a milkweed leaf
 

Scientist Hillary Sardiñas, who works as CDFW’s pollinator coordinator in the Wildlife Diversity Program, recalls a moment several years ago when she showed her young daughter a monarch caterpillar, and realized it’s a species her daughter might not grow up to enjoy.

“It really hit home in a personal way how important it is to conserve the species,” said Sardiñas.

The population of migratory western monarchs has declined more than 99 percent since the 1980s when millions overwintered in groves along the California coast. By the mid-2010s, the population had dropped to the hundreds of thousands. Just a few years ago, scientists estimated there were only 30,000 left. Now there are only about 2,000 migratory western monarchs left statewide.

“Western monarchs may be headed toward extinction in California, and we need to take drastic and immediate action to help recover the population,” said Sardiñas.

Western monarchs overwinter along the California coast from San Diego to Mendocino County, expanding during springtime along the Central Coast and Central Valley. They ultimately migrate into other states west of the Rocky Mountains to breed.

The drastic population decline has been attributed to several factors including habitat loss, climate change and exposure to pesticides. Western monarchs’ overwintering habitats continue to be destroyed or altered by human development, especially along the Central Coast. Development is also reducing nectar resources. Climate change may be causing monarchs to leave overwintering sites earlier than usual and before milkweed, their host plant, has fully bloomed. This causes what scientists call a “phenological mismatch,” meaning monarchs at times don’t have a place to lay eggs and lack the ability to create the next generation in their multi-generational life-cycle.

In addition to population decline, scientists are seeing a new and possibly dangerous phenomenon—an increase in resident monarchs that remain along the coast year-round and don’t migrate. These monarchs are encouraged to stick around by a non-native milkweed which allows them to breed all throughout the year. The phenomenon might seem like a novel adaptation, but scientists are finding that resident monarchs can have up to 10 times the occurrence of a protozoan parasite known as OE (Ophryocystis elektroscirrha). OE can be transmitted through contact with milkweed leaves, and leads to wing deformation, poor health, decreased reproductive ability or death.

To conserve the population, CDFW is taking action on several fronts:

  • In partnership with the Western Association of Fish and Wildlife Agencies, CDFW helped develop a 50-year management plan for western monarch conservation, published in 2019. Two major focus areas of the plan are management of overwintering sites on the California coast and restoration of breeding and migratory habitat in the Central Valley.
  • In partnership with nonprofit River Partners and with funding from the Wildlife Conservation Board’s Monarch Butterfly and Pollinator Rescue Program, CDFW is restoring and enhancing 500 acres of land for monarchs and pollinators in the Central Valley.
  • On its properties throughout the state, CDFW is enhancing and restoring 1,500 acres of habitat for pollinators and monarchs through management actions and planting milkweed and nectar plants.
  • CDFW is improving management strategies on four department-owned overwintering sites.
  • CDFW is increasing milkweed availability for habitat restoration projects by collecting seed from our properties and partnering with local nurseries.
  • CDFW is also helping coordinate conservation action among stakeholders by participating in the Rangeland Monarch Working Group and co-leading the Monarch Plant Materials Working group with the Xerces Society for Invertebrate Conservation.

Julea Shaw, an environmental scientist in CDFW’s Lands Program, helps coordinate the department’s conservation and restoration efforts. Through her work, she is often reminded how California residents have a personal connection to the western monarch species.

“I speak to so many people who remember growing up seeing thousands of monarchs. It shows how impactful the species can be and how they capture peoples’ imaginations,” said Shaw.

There are several actions that residents can take to help conserve western monarchs.

First and foremost, residents can help by planting locally native milkweed and nectar plants. When choosing nectar plants, conservationists recommend choosing plants that bloom in early spring and late fall when resources tend to be scarce.

Second, residents can help by reducing or eliminating pesticide use in their own gardens.

Third, monarch enthusiasts can help conservation efforts by participating in community science projects. There are multiple organizations which train volunteers to count western monarchs at overwintering sites. In fact, much of the current data on declines in western monarch populations was collected in part by community scientists.

Finally, a note on captive rearing. CDFW would like to remind California residents that a scientific collection permit is required to handle and/or conduct research on western monarchs. Rearing monarchs without proper training can lead to health problems that further exacerbate the species’ decline. Recent research shows that captively reared monarchs can be weaker, have smaller wingspans, and be less adapted to migrate.

“It’s going to take a collective effort between residents and conservation scientists to turn the species around. We’re diligently working to expand our efforts—but the work won’t be done anytime soon,” said Sardiñas.

CDFW Photo

Categories: Science Spotlight
  • June 21, 2021
Scientist, Michael Mammola holding a fish on a lake with blue sky

Michael Mamola, CDFW’s Statewide Trout Management and Stocking Coordinator, shows off a Lahontan cutthroat trout before its release into Echo Lake earlier this spring.

hand holding a fish for release in a lake
The Lahontan cutthroat trout is the largest inland trout species in the world and the only trout native to the Lake Tahoe Basin.

Visitor fishing off the side of a pier in a lake
Few visitors to Echo Lake pause to fish and probe the waters for the Lahontan cutthroat trout that live within.

fish in a lake
Lahontan cutthroat trout grow large in Echo Lake, El Dorado County, thanks to the large population of forage fish, principally the Lahontan redside minnow.

California anglers looking to target the native but elusive Lahontan cutthroat trout may want to put Echo Lake in El Dorado County on their summer itinerary.

For the past several years, the California Department of Fish and Wildlife (CDFW) has managed the deep blue waters of Echo Lake exclusively as a Lahontan cutthroat trout sport fishery.

That’s the same fish that has turned Nevada’s Pyramid Lake and its monster-sized cutthroats into a global fishing destination and created a cult following at Heenan Lake in Alpine County among fly anglers looking to tangle with a trophy cutthroat.

Located just minutes off U.S. Highway 50 near South Lake Tahoe at an elevation of 7,500 feet, Echo Lake may offer California anglers their best chance to encounter the Tahoe Basin’s native trout species given the combination of an easy drive, a plentiful fish population supported through a generous stocking regimen, and wide-open fishing access without the restrictions on seasons, take or tackle methods found at some other Lahontan cutthroat trout fisheries.

Adding to the overall experience, Echo Lake receives relatively little fishing pressure. The 300-acre lake is best known as a jumping-off point for the southern portion of Desolation Wilderness. Few of those backcountry travelers, however, pause to wet a line at Echo Lake.

“It’s sort of a hidden gem,” says Mitch Lockhart, CDFW’s District Fisheries Biologist for El Dorado, Placer and Nevada counties. “You’ll not be combatting for space to fish here.”

Echo Lake received a recent stocking of 100 brood stock Lahontan cutthroat trout from nearby Heenan Lake. Resplendent in their crimson spring spawning colors, the fish ranged in size from two to nine pounds with an average weight of two to three pounds. CDFW followed up that trophy stocking with a plant of some 20,000 “sub-catchable” Lahontan cutthroat trout in the seven- to nine-inch range.

Echo Lake’s recent history as a Lahontan cutthroat trout fishery resulted from a collaboration between lakeside property owners and CDFW. Cabin owners were seeking improved fishing opportunities given recent cutbacks and elimination of hatchery stockings of rainbow trout, brown trout and brook trout. At the same time, CDFW fisheries biologists were looking for suitable locations to stock Lahontan cutthroat trout into their historic range in the Tahoe Basin and expose more anglers to the unique, native fish.

Echo Lake fit the criteria. Its steep-sided granite cliffs, clean, cold deep waters are reminiscent of Independence Lake in Nevada County and Fallen Leaf Lake in El Dorado County, two historic and active Lahontan cutthroat trout fisheries.

Echo Lake also is relatively isolated from other waters and protected from infiltration by non-native trout species. The lake holds some small, remnant populations of brook and brown trout with little opportunity for wild rainbow trout to access the lake and colonize it from surrounding waters. Displacement, hybridization and competition from non-native trout is largely what earned the Lahontan cutthroat trout listing under the federal Endangered Species Act 51 years ago and what mostly prevents large-scale recovery efforts today.

And unlike some other high Sierra lakes where trout eke out a meager existence in near-sterile conditions, Echo Lake is rich with food in the form of the Lahontan redside, a native minnow that has proven an important forage fish responsible for Lahontan cutthroat trout growth rates of two to three inches a year in Echo Lake.

Anglers reported catching Lahontan cutthroats to 26-inches last year with the average size being closer to 12 to 14 inches with an occasional 16-, 18- and 24-inch fish in the mix. CDFW biologists say they are seeing anecdotal evidence of natural spawning, but plan to manage Echo Lake primarily for recreational fishing and not species recovery.

CDFW has stocked two strains of Lahontan cutthroat trout into Echo Lake, the Pilot Peak strain of Pyramid Lake fame that can reach sizes in excess of 20 pounds, and the smaller Independence/Summit Lake strain of fish from eggs collected at Heenan Lake and raised at the American River Trout Hatchery outside of Sacramento.

A Lahontan cutthroat trout caught and documented from Echo Lake qualifies for CDFW’s Heritage Trout Challenge, which incentivizes and rewards anglers for catching six different forms of California native trout from their historic drainages.

In addition to easy drive-to access, Echo Lake features a popular marina, boat launch and convenience store where kayaks and canoes can be rented. Private boats and other waterfcraft can be launched only after mandatory inspection and certification that they are free of aquatic invasive species.

CDFW Creates Lahontan Cutthroat Trout Sport Fishery at Echo Lake (Video)

CDFW Photos:

Categories: Science Spotlight
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