Science Spotlight

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  • January 13, 2022

The California Fish and Wildlife Journal concludes its 2021 Special Issue installments with the winter quarter’s Special Issue: Effects of Human-Wildlife Interactions on California’s Natural Resources: Conflict and Coexistence (PDF). With this year’s unprecedented drought, unpredictable fire season, climate change, pandemic response, and increased human-wildlife conflict reported statewide, issue 107-3 is salient and timely. In this Special Issue, we explore various interconnected themes across four sections: Terrestrial Predator Interactions, Conflicts & Adaptive Management, Coexistence & Conservation, and the Human Dimensions of Wildlife Conservation.

cover of Journal showing fox, with city in background

The California Department of Fish and Wildlife (CDFW) serves as the lead state agency charged with helping to resolve human-wildlife conflict, public safety, and reported depredation (property damage) and committed to advancing discussion and deeper understanding of human-wildlife interactions throughout the state. People live increasingly in close contact with animals, both wild and domestic, as the human population expands along the wildland-urban interface and increases over time. This reality has led to increased human-wildlife interactions and reported  human-wildlife conflict. Negative human-wildlife interactions can directly affect human and wildlife health and may result in loss of livelihood, reduced wellbeing, or in some instances, loss of life – animal or human.

Come read about the various types of human-wildlife interaction, some of the unique challenges – and opportunity – to better address understand and address human-wildlife conflict. Various agency partners, practitioners, researchers, and key stakeholders have contributed their expertise to this Special Issue. We hope you recognize the myriad factors that can shape our perception and approach to wildlife in California. Learn more!

The California Fish and Wildlife Journal has published high-quality, peer-reviewed science for more than 100 years – and the CDFW looks forward to more valuable contributions ahead.

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Categories: California Fish and Game Journal, Science Spotlight
  • 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
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