Science Spotlight

Habitat is the key to the long-term survival of Sacramento River winter-run Chinook in California. Since 1999, CDFW has been working with multiple agencies and private parties on planning efforts to restore the population of these endangered salmon. More than $100 million has been allocated to specific habitat restoration work on Battle Creek, which comprises approximately 48 miles of prime salmon and steelhead habitat.

Over the next two months, approximately 200,000 juvenile winter-run Chinook will be released into the North Fork of Battle Creek. The introduction of these fish, which were spawned from adults last summer, is occurring sooner than expected due the availability of fish from the Livingston Stone National Fish Hatchery Winter-run Chinook Captive Broodstock Program. The fish were raised at Coleman National Fish Hatchery and are being released by Coleman Hatchery personnel. These additional fish could help bolster the winter-run Chinook population and be a potential catalyst in their recovery.

CDFW Senior Environmental Scientist Doug Killam has worked on the Battle Creek Reintroduction Plan for nearly a decade and has been instrumental in moving in-stream projects forward. Killam sees the release of 200,000 smolts as an important step in the overall effort. The release will reestablish winter-run Chinook in a new drainage and create a separate new population. Currently there is only one viable population existing in the Sacramento River directly below Keswick and Shasta Dams. The recent drought affected the volume of the critical cold-water pool in Shasta Lake and the release of warmer water in the drought years of 2014 and 2015 resulted in major losses to eggs and young salmon below the dam. Biologists have long recognized that having more than one winter-run Chinook population is imperative for the long-term survival of the species.

A volcanic region with rugged canyons and dramatic scenery, the North Fork of Battle Creek is unique since it has both cold snowmelt water and large amounts of spring water flowing into it at critical times for winter-run salmon to hold over in and spawn in. It is also one of a handful of waters that can support all four of the Chinook salmon runs that return to the Sacramento River Basin. Hydroelectric development of the creek in the early 1900s largely eliminated winter-run Chinook and other salmonid runs from swimming far upstream to access the cooler water required for these unique summer spawning salmon. Recent efforts to bring the fish back to the North Fork include dam removals, rock fall removal, new fish ladders and fish screens and – most importantly – an agreement to increase stream flows to provide fish with the water quantity and quality they need to survive and thrive in this important keystone stream.

CDFW photo by Heather McIntire. Map by CDFW Fisheries Branch.

For residents of Humboldt and Del Norte counties, the majestic Roosevelt elk is a common sight. Although Roosevelt numbers were dwindling in California by the 1920s, conservative management strategies and limited hunting opportunities have helped them to rebound. Today, researchers have identified more than 20 distinct groups of elk in these two counties, many of which consist of well over 50 animals.

This conservation success story doesn’t come without a downside, though. Elk require large amounts of food to survive, and they tend to graze where food is most plentiful – often in agricultural areas and residential neighborhoods, where they cause damage to crops, landscaping, fencing and other private property.

Partly in response to rising concerns about property damage caused by the Humboldt and Del Norte herds, CDFW scientists are working on a wide-ranging, long-term study of Roosevelt elk population size and growth, herd movements, habitat use, disease and causes of mortality. The project, which is a collaborative effort with researchers from Humboldt State University, will collect critical baseline information about the animals that will help CDFW develop more robust and efficient methods for monitoring the herds, set future hunt quotas, inform local agencies about elk management and manage depredation issues. CDFW initiated this project in 2016 and expects to continue data collection efforts through 2018.

Tracking and studying one of the largest mammals in California is a much more complex undertaking than one might think. Roosevelt elk herds are wide-ranging and tend to graze in areas that are not easily accessible. Traditionally, CDFW relied on aerial surveys to monitor population trends of big game species such as elk, but such surveys are only feasible in a small portion of northwestern California because visibility is limited by steep terrain and dense vegetation. Ground surveys have similar constraints and are further limited by the small amount of occupied habitat that can be easily accessed from roads.

Given these constraints, CDFW scientists are employing multiple survey methodologies for the current study. Different techniques will be used in different habitat types. For example, in hard-to-reach areas, trail camera footage will be compared to visual surveys and used to collect herd composition data and estimate population size. Estimates will also be derived from analyzing the DNA contained in elk droppings.

CDFW also monitors the movement of the Roosevelt elk via electronic collars. There are currently 20 collared elk in coastal Del Norte and northern Humboldt counties and researchers hope to extend this project into central Humboldt County this winter, with plans to collar as many as 30 additional elk. Captured animals are also marked with ear tags, which allow for individual identification.

These survey efforts, and similar efforts elsewhere in the North Coast Roosevelt Elk Management Unit (EMU), are outlined in California’s Draft Elk Conservation and Management Plan, which is available for public review and comment through Monday, January 29. The plan provides guidance and direction to help set priorities for elk management efforts statewide.

CDFW photo: Environmental Scientist Carrington Hilson monitors a Roosevelt elk during a survey of the population.

A California red-legged frog sits motionless at the edge of McClure pond at the Sparling Ranch Conservation Bank. Photo by Ashley Spratt/USFWS


McClure pond is one of the most productive California red-legged frog ponds at the Sparling Ranch Conservation Bank. Like many of those on Sparling Ranch, it was named after the family who homesteaded in site in the late 1800s. Photo by Ashley Spratt/USFWS

Since the mid-1980s, California has been using a system of conservation and mitigation banking to protect valuable natural resources and critical habitat for fish, wildlife and plants. These banks are generally large, connected, ecologically meaningful areas of preserved, restored, enhanced or constructed habitat (for example, wetlands) that are set aside for the express purpose of providing mitigation for project impacts. Conservation banks provide mitigation for impacts to listed species and habitats, while wetland mitigation banks primarily provide mitigation for wetland impacts. Together, they serve to prevent inadequate, fragmented reserves that can result when mitigation projects are carried out individually.

Banks work by establishing credits for sensitive species or habitats found on a given site. These credits can then be sold to developers or other project proponents who need to meet permitting requirements or are otherwise required to compensate for environmental impacts. For those parties needing to mitigate for project impacts, banks serve to streamline the regulatory process by providing a pre-established mitigation site that the regulating state and federal agencies have already confirmed will provide adequate and appropriate mitigation for certain habitats or species. By mitigating at a bank, project proponents can avoid the time and cost of searching for a suitable mitigation site and protecting it in perpetuity themselves.

In order for the banking system to be effective, state and federal agencies must work closely together to align processes and practices. Since 1993, CDFW has been participating in the planning, review, approval, establishment, monitoring and oversight of 81 banks statewide. Other agencies that typically participate in the regulation and approval of conservation banks include the U.S. Army Corps of Engineers (USACE), U.S. Environmental Protection Agency (USEPA), Natural Resources Conservation Service (NRCS), U.S. Fish and Wildlife Service (USFWS) and the National Oceanic and Atmospheric Administration National Marine Fisheries Service (NOAA NMFS).

To read more about one of these successful partnerships, please visit USFWS’ newsroom.

Learn more about CDFW’s Conservation and Mitigation Banking program, on our website.

All photos courtesy of U.S. Fish and Wildlife Service.

Top photo: A herd of cattle graze atop a hillside at Sparling Ranch near Hollister, Calif. Photo by Ashley Spratt/USFWS.

Lassics lupine grows under protective cages.


Richard Macedo, Habitat Conservation Planning Branch Chief constructs a cage to protect rare, endangered Lassics lupine.


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:

• Report to the Fish and Game Commission, Evaluation of the Petition from Mr. David Imper and Ms. Cynthia Elkins to List the Lassics Lupine (Lupinus constancei) as an Endangered Species under the California Endangered Species Act (PDF).
• Kurkjian, H.M., S.K. Carothers, and E.S. Jules. 2016. Seed predation has the potential to drive a rare plant to extinction. Journal of Applied Ecology 54:862–871.

California Department of Fish and Wildlife photos by Jeb Bjerke

The latest issue of California Fish and Game, CDFW’s scientific journal, is now available online. This century-old quarterly journal contains peer-reviewed scientific literature that explores and advances the conservation and understanding of California’s flora and fauna.

The endangered salt marsh harvest mouse (Reithrodontomys raviventris) graces the cover of California Fish and Game, Volume 103, Issue I. Researchers ventured into the pickleweed to study the tiny mouse, which is endemic to the marshes surrounding the San Francisco Estuary Bay and its tributaries. The mice were fitted with tiny radiotelemetry collars and tracked for three years. Researchers documented some curious behavior in the resulting paper, “Potential evidence of communal nesting, mate guarding, or biparental care.” The accompanying photos provide a fascinating glimpse into an active nest.

Another paper, “Documentation of mountain lion occurrence and reproduction in the Sacramento Valley of California,” explores the potential for mountain lions to exist in fragmented habitats if there is adequate connectivity with larger blocks of suitable habitat and sufficient prey. The study used camera traps to document populations of mountain lions in the Sacramento Valley’s Butte Sink, which is made up of relic riparian habitats interspersed with managed wetlands. The photos show healthy mountain lions moving through habitat that has long been considered unsuitable due to extensive agricultural and urban development.

The article, “Mussels of the Upper Klamath River, Oregon and California,” reports on sampling efforts that expand existing baseline population data on freshwater mussels in the Upper Klamath River. The sampling efforts may ultimately assist with protection, mitigation and enhancement efforts for large bi-valve species.

The final paper provides insights into the benefits deer and elk derive from licking mineral rocks. Researchers took samples of “lick sites” that were used by California black-tail deer (Odocoileus hemionus columbianus) and Roosevelt elk (Cervus canadensis roosevelti) in the Klamath Mountains, Siskiyou County. After performing a detailed analysis of the elemental content of each lick site, the researchers concluded that each lick site offers a different smorgasbord of minerals, and in varying concentrations. The study’s objective is to begin identifying, classifying, and analyzing important mineral lick sites to benefit future ungulate management efforts.

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.

Download the entire Winter Issue 103 (PDF) in high resolution, or browse individual articles in low resolution.