Science Spotlight

VegCAMP staff researching at Carrizo Plain, San Luis Obispo County


VegCAMP staff working at Modoc Plateau, Modoc County


Lightning-caused fire witnessed by staff, Mono County


Slinkard Valley Wildlife Area vegetation map

California is home to more than 6,500 plant species, which offer sustenance and shelter to more than 1,000 animal species (this figure doesn’t include invertebrates).

In fact, part of the mission of the California Department of Fish and Wildlife (CDFW) is to manage the habitats upon which our fish and wildlife species depend. The cornerstone of those management efforts is knowledge of the plant assemblages that are unique to each habitat – where these natural communities are located, how prevalent (or rare) they are, and monitoring how their distribution may shrink or grow over time.

CDFW has three vegetation ecologists (Rachelle Boul, Betsy Bultema and Jaime Ratchford), a geographic information systems (GIS) specialist (Rosie Yacoub) and a unit supervisor (Diana Hickson) dedicated to exactly that task. Known as the Vegetation Classification and Mapping Program (VegCAMP), this team works year-round to identify, record and map all of the natural communities (also known as vegetation types) that grow in California’s 163,000 square miles. VegCAMP also relies on the mapping expertise of four contracted employees, paid through an arrangement with California State University, Chico.

According to Hickson, having a complete, reliable map of California’s vegetation is an invaluable scientific tool. “We need knowledge of where the vegetation is in order to make good management decisions, such as determining the best place to put a preserve, for example,” she says.

VegCAMP tackles this task by sampling, classifying, defining, naming and mapping the natural communities of an area – such as the Suisun Marsh, Point Reyes, Western Riverside County or the Mojave Desert. Some mapping areas encompass an entire eco-region (the Mojave Desert mapping area, for example) while some are as small as a 2,000-acre ecological reserve.
The process of classifying and mapping a CDFW property, for example, generally requires eight to 10 people to survey the property, taking detailed notes and pictures to describe the vegetation at different locations. The “boots on the ground” effort doesn’t have to cover every square inch, fortunately. The process requires collecting vegetation samples from a small portion of the mapping area (depending on the complexity), then extrapolating to determine the most likely makeup of the entire area. The data is then brought back to the office to be classified, and each location visited can be given a vegetation name. These locations on the ground are compared to aerial imagery and lines are drawn around each community type and labeled. Another measure of checks and balances is to have a second field crew survey known locations of each community, without having knowledge of the previously mapped attributes.

All of this information is entered into the VegCAMP database, where classification software and GIS tools allow users to gain a tremendous understanding of what comprises a particular area. “One map contains many different attributes,” Hickson explains. “For example, we can query the polygons (each mapped ‘patch’) to show acreage of conifer types, and then we can narrow the search to those conifer types that are tall or short, those that are regenerating or those that have a shrub layer under them. That’s the power of GIS layers.”

The data collected and recorded by the VegCAMP team has far-reaching implications, and is used by other agencies, nonprofits and partners as well.

Seeing the practical application of their work is a satisfying payoff for Hickson and her crew. For example, the VegCAMP team spent several years meticulously mapping Mendocino County’s Pygmy Forest, which is dominated by a few conifer species that grow to a height of six feet or less, due to nutrient-poor soil that saturates in the winter and dries completely over the summer. Over time, the team produced a comprehensive map that showed how much vegetation had been lost to residential development and cannabis grows, as well has how much remained. 

“As a result of our mapping, the county recognized the need to require more environmental assessment for proposals for development in that habitat,” Hickson explained. “It’s raised awareness of the vulnerability of that vegetation type.”

Vegetation ecologist Rachelle Boul also finds satisfaction in her work with VegCAMP. Her mapping efforts have largely been focused in the Suisun Marsh area in Solano County. This highly managed area is home to rare species such as the salt marsh harvest mouse, and CDFW works with the California Department of Water Resources and private duck clubs to maintain habitat for them while also allowing access for duck hunting. Here, VegCAMP remapped the vegetation every three years in order to determine if there had been any negative impact.

Boul noted the importance of aerial images, including those taken by satellite – VegCAMP has access to the photos taken by the US Department of Agriculture’s National Agriculture Imagery Program – and drones. “You can only make a vegetation map as good as the imagery that you interpret from. It’s just made it so much easier to be more accurate and more fine scale,” she said.
Boul says that it’s the diversity of her duties – from field work to data analysis to mapping vegetation and finally sharing that data with CDFW partners – that keeps her motivated and passionate about her job.

Being able to spend time in nature is certainly a perk for the VegCAMP ecologists but that’s not to say there aren’t job-related hazards. Both Hickson and Boul remember a particularly harrowing day in August 2017, when they were field mapping the Slinkard/Little Antelope Wildlife Area in Mono County, and a lightning strike touched off a fire. The VegCAMP team reported the fire immediately and were soon joined by CalFIRE helicopters and ground crews. Map-making took a back seat that day to field safety and group communication.

Despite the size and length of the fire (nearly 9,000 acres and several days), it didn’t really impact the work of VegCAMP. Nerves may have been rattled, but fortunately nearly all of that mapping area (work still in draft form) was untouched by flames.

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Media Contact:
Tim Daly, CDFW Communications, (916) 201-2958

(CDFW Photos)

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.

Deep in the pickleweed in the San Francisco, San Pablo and Suisun Bays, the tiny salt marsh harvest mouse (Reithrodontomys raviventris) tries to avoid predators and compete with other species for prime habitat. Food and cover are abundant, but its overall habitat is shrinking as humans encroach upon its home range. In south San Francisco Bay alone, 95 percent of the historic salt marsh has been lost to industrial parks and subdivisions. Annual flooding in the winter can be perilous, too -- when vegetation is topped by rising tides, the mice must scramble to find taller vegetation or into upland habitat (grasses around the wetlands that don’t get flooded by the tides).

As part of the effort to monitor and conserve this state- and federally-listed endangered species, biologists conduct annual surveys of the salt marsh harvest mouse. The effort involves setting up traps stuffed with cotton batting and baited with birdseed and walnuts, taking measurements and collecting other data on the subjects that are captured. In some studies, the mice are fitted with GPS collars for tracking, or ear tags to help identify them upon recapture. In other studies, the biologists simply clip away fur on the mouse’s flank or neck – another method that helps them determine whether a mouse in a trap has crossed paths with them before.

Once a mouse’s measurements have been recorded, they are set loose to scamper back into the pickleweed. The data that’s been collected will later be entered into a larger database that will be accessible to researchers from multiple state agencies (CDFW, the Department of Water Resources), federal agencies (US Fish and Wildlife Service, the US Geological Survey), educational research institutions (UC Davis, CSU San Marcos, San Francisco State) and private industry.

By comparing population fluctuations and other data throughout the range, scientists hope to identify threats and increase their understanding of this rare rodent’s biology and behavior – ultimately helping to better inform future decisions on habitat management, restoration and enhancement efforts.