BRD Activities in California

• Research by BRD scientists at the Western Ecological Research Center (WERC), headquartered in Sacramento on the California State University campus, is providing natural resource managers in California with information they need to make decisions on issues such as water use, livestock grazing, wildland fires, invasive species, environmental contaminants, declining populations of native species, and urban development.
• WERC sea otter research focuses on this smallest marine mammal's role as keystone species in a nearshore food web. In California, WERC researchers study the threatened southern sea otter population. Recent changes in the distribution and abundance of sea otters in California will require careful consideration of new management action options. Results of this research will be of interest to the U.S. Fish and Wildlife Service, California Department of Fish and Game, the fishing industry, and conservation groups.
• The white abalone is a deep-water, marine snail, sought as a precious food resource from southern California until its crash in the 1970s. WERC scientists are working with colleagues at the University of California, Channel Islands Marine Research Institute, Channel Islands National Park, and California Department of Fish and Game and contributing information on the species' habitat and needs and for the development of a captive breeding program similar to what has been used to replenish imperiled terrestrial species.

• Urban, industrial, and agricultural activities have contaminated the San Francisco Bay area with petroleum hydrocarbons, organochlorine pesticides, PCBs, metals, and trace elements, reducing the quality and quantity of wildlife in the estuary. WERC scientists are studying the effects of these contaminants on wildlife in the estuary and in California rivers where contaminants are still leached from mines that suspended operation over a century ago. Partners include the California State Water Resources Control Board, National Park Service, and U.S. Fish and Wildlife Service.

• San Francisco Bay is the largest estuary on the west coast and a highly urbanized ecosystem, where more than 90 percent of tidal wetlands have been lost to reclamation for farmland, salt evaporation ponds, or homes and industry. WERC is providing science support for rehabilitation of diked wetlands and salt ponds to tidal marsh, important to the recovery of the estuarine ecosystem.

• Human population growth, urbanization, and loss of habitat are affecting migratory birds and associated coastal systems. WERC research is adding information on migratory bird distributions, life histories, and habitat use in coastal maritime communities. This science can be used for future land-use decisions critical for conserving coastal natural resources, human quality of life, and economic prosperity. Among the partners for current projects are the California Department of Fish and Game, California Department of Water Resources, Point Reyes Bird Observatory, U.S. Fish and Wildlife Service, and U.S. Bureau of Reclamation.

• California's biodiversity and the continued survival of functioning native ecosystems are threatened by the invasion of nonnative species. Once established, some invasive species have the ability to displace or replace native plant and animal species, disrupt nutrient and fire cycles, and cause changes in the pattern of plant succession. Under the USGS "Weeds in the West" initiative of 1998, WERC began research that will improve the ability to detect, monitor, and predict the effects of invasive plant species. The projects address critical needs in California's Central Valley, the Mojave Desert, selected national parks, and other sensitive areas in California. This research will provide resource managers with the information and tools needed to better understand and control invasive weeds on the land they manage and to help them avoid or prevent future invasions. Equally important research is being conducted by WERC scientists on exotic animals in California, including bullfrogs, African clawed frogs, European green crabs, and feral burros.
• Invasive plants and animals affect coastal maritime communities including terrestrial and nearshore ecosystems. The European green crab is decimating shellfish populations and altering natural systems on the east and west U.S. coasts. WERC research is testing biological controls to find an effective and safe response to stem this invasion. Invasive, exotic plants have displaced native plants that have become rare on island and coastal lands. Research on treatments for invasives provides resource managers with management options for conserving natural environments and plant diversity.
• WERC research on desert tortoises is revealing human impacts on populations and habitat of this threatened species, and includes investigations of their reproductive output, diseases, predation, survivorship, and the fate of environmental contaminants along roadways. These and other studies of desert ecology are providing information that supports development of scientifically based habitat conservation plans by management agencies. Partners include the California Department of Fish and Game, California Energy Commission, University of California, Bureau of Land Management, National Park Service, and Department of the Army.
• WERC research has documented the legacy of human occupancy of the Mojave Desert and land uses that have altered the desert ecosystem. Studies on species such as saltcedar and nonnative grasses show how invasive species may reach even remote parts of the desert. Current studies on invasive species include investigations into how nonnative grasses are affecting desert tortoise habitat, the profound effects of plant invasions and wildfire on native plants and animals, and the response by native and nonnative plants to elevated amounts of carbon dioxide in the atmosphere. Other studies are shedding light on ecology of bighorn sheep at Death Valley National Park and in the vicinity of the Eagle Mountain landfill project. Federal and state partners are associated with Mojave Desert projects.
• The pilot project of the Natural Communities Conservation Planning (NCCP) program focuses on protection of coastal sage scrub communities within a 6,000-square-mile planning area spanning five southern California counties. This planning effort is the subject of a WERC study and research support for state and federal partner agencies. WERC in collaboration with the University of California, San Diego, is conducting research on the ecology and conservation biology of reptiles and amphibians. This work focuses on determining habitat-use, seasonal activity patterns, diversity patterns, timing of reproduction, and other life-history parameters for all the species that occur in the study area.
• WERC scientists are making important contributions to the scientific foundations upon which habitat conservation plans (HCPs) are developed and analyzed. They collect field data on the biology of the species in question, the habitat, and the ecological processes that provide suitable conditions necessary to maintain self-sustaining populations for individual species such as the desert tortoise, and for groups of species such as waterfowl and marine mammals. Primary areas of support are ecological field data, reserve design, impact analysis, ecological monitoring, and planning and decision support. Federal, state, and private partners are associated with projects.
• WERC scientists are working cooperatively with colleagues at the University of California, Santa Barbara, and Montana State University to develop a computer-based framework for incorporating biological data, socio-economic data, and optimization modeling to support the assessment and visualization of conservation plan alternatives. By blending the most current technologies with credible biological evaluations and practical decision-making processes they hope to enable better, more informed choices in habitat conservation plan (HCP) development. The result will be an accessible, practical computer tool for HCP planning teams, using off-the-shelf software combined with customized modules tailored for the HCP process.
• Arid habitats of California's southern San Joaquin Valley have become choked with dense growth of nonnative grasses, where there was once relatively bare ground between the native salt bushes. Some native annual wildflowers, such as the federally endangered Kern mallow, are disappearing from the southwestern San Joaquin Valley because they cannot effectively compete with the nonnative grasses. Wildlife also is declining, and some species are now threatened or endangered, including the blunt-nosed leopard lizard, giant kangaroo rat, and San Joaquin antelope squirrel. These animals, which rely on rapid locomotion across relatively bare ground to catch food and escape predators, are being adversely affected by the disappearance of open ground as the nonnative grasses invade the desert. With more than a dozen cooperators including state and federal agencies and private organizations and companies, researchers at WERC are carrying out an experiment to see if well-managed herds of cattle can be used to reduce the amount of accumulated grass, and thus benefit the declining plants and animals.
• Perennial pepperweed is an invasive weed found throughout California and in all of the western United States. Populations of pepperweed can establish and spread by seeds or by root fragments, enabling the species to expand into large monotypic stands in a variety of environments including wetland perimeters, rangelands, meadows, riparian areas, salt marshes and estuaries, roadsides, irrigation channels, and even irrigated alfalfa fields. It poses a serious threat to many native undisturbed areas as well as previously disturbed areas that are undergoing restoration, with a potential to displace threatened and endangered plant and animal species. WERC and University of California, Davis, researchers are collaborating to better understand environmental factors that influence the spread of perennial pepperweed, information that will be especially important to refuge managers. Experiments have been established throughout three bioregions of California-the Klamath region, the Central Valley, and the San Francisco Bay region-to evaluate the rate of spread and how species diversity, species composition, soil moisture, and salinity influence the spread of perennial pepperweed.
• Since the 1970s, nonnative grasses have invaded the desert and become increasingly dominant in native plant communities in the Mojave Desert. Recent WERC studies have shown that nonnative annual grasses now dominate most plant communities in the Mojave Desert. They ignite easily and carry fire rapidly and unbrokenly across the landscape. The increasing dominance of these grasses and a burgeoning human population in the Mojave Desert have led to more fires, which threaten native perennial plants that are poorly adapted to survive the increasing frequency and intensity of these fires. Wildlife is killed by fire, and those animals that survive may be adversely affected by changes in the structure of their habitat. WERC studies are in progress to further evaluate the effects of fire and develop postfire restoration techniques that minimize the dominance of nonnative annual grasses in the Mojave Desert. Partners include the University of California, Bureau of Land Management, and National Park Service.

• Recent WERC research in California's southern Sierra Nevada shows that grazing by different types of livestock in foothill woodlands may alter species composition and distribution of plant functional types or growth forms. In the higher elevation coniferous forests, invasive plants have not previously posed a significant threat. However, the recent reintroduction of fire to these forests may provide conditions conducive to the invasion and spread of some weeds. WERC research in the southern Sierra Nevada has shown that gaps created by high-intensity fires are particularly susceptible to invasion by nonnative plant species. The lower elevation ponderosa pine forests are potentially most susceptible to new invasions, and particularly troublesome is the apparently recent expansion of cheatgrass in these forests in Kings Canyon National Park. Early control of this apparent invasion is of concern to resource managers in Sierra Nevada parks, and a more detailed study of fire and other concerns regarding cheatgrass invasion are currently being investigated by WERC scientists.
• Fire is recognized as the most important disturbance in many forest ecosystems, yet the relationships between fire regimes and climate variations is poorly understood. Scientists at WERC are working with colleagues from other research institutions, including the University of Arizona, University of California at San Diego, Duke University, and Montana State University, to explore the fundamental character and significance of forest changes in the Sierra Nevada that are driven by climate and fire. Using state-of-the-art computer models, these researchers are integrating long-term studies in fire regimes, climate, topography, soils, forest demography, seeding dynamics, paleoecology and forest modeling. With the capability of examining landscapes of 10,000 to 100,000 hectares, their models can help land managers focus monitoring efforts on those areas most likely to respond to climatic change, and predict which portions of the landscape are highest priority for mitigation efforts.
• Despite wetland losses of over 90 percent in this century, the Central Valley of California has remained one of the most important areas for migratory waterfowl in North America. Remaining wetlands, flooded agricultural fields, and wildlife refuges from Redding to Bakersfield provide a winter home to 60 percent of the ducks and geese that migrate along the Pacific Flyway, 20 percent of all North American waterfowl. WERC and partners are evaluating the impact of habitat restoration on migratory waterfowl in the valley. The study will provide information on the kinds of habitats wintering waterfowl select for feeding and roosting. It will also indicate how the location and management of habitats affect their use. Scientists in trucks equipped with cab-mounted directional antennae and specialized receivers to pick up transmitter frequencies track the location of 320 ducks and geese, each fitted with small radio transmitters, around-the-clock during winter until the birds migrate north in the spring. Many partners are involved including the California Department of Fish and Game, U.S. Fish and Wildlife Service, California Waterfowl Association, Ducks Unlimited, Grassland Water District, Central Valley Habitat Joint Venture, U.S. Bureau of Reclamation, and The Rice Foundation.
• Scientists from WERC, Ducks Unlimited's Institute for Wetland and Waterfowl Research, and the California Waterfowl Association are using satellite telemetry to track spring migration of female northern pintails that winter in the Central Valley, California. They are striving to discover why the North American breeding population of northern pintails has declined over the last 30 years. In 1999, the breeding population was 3.0 million, well below the long-term average and objective level established by the North American Waterfowl Management Plan of 5.6 million.
• Recent evidence indicates that amphibians are declining globally. This decline may be one of the most serious conservation problems in the U.S. today because it is occurring in our largest park and wilderness areas where healthy, seemingly well-protected populations have disappeared for no obvious reason. These losses are important both because of the reduction in biodiversity and because amphibians are sensitive biological indicators of the health of the environment. WERC research with state and federal partners is designed to evaluate the status of amphibians in California, identify potential causes of decline, investigate selected factors for their role in declining amphibians, and conduct experimental reintroductions of selected species.
• The current prescribed burning program in the Sierra Nevada national parks is based on sound research conducted over the past two decades. Better information is needed to determine whether specific areas need to burn, and if so, how frequently. The rate at which fuels accumulate is key to these decisions. WERC scientists are conducting research determine fuel accumulation rates for eleven Sierra Nevada conifer species, including information on deposition and decomposition of needles, branchwood, cones and bark particles. This research will help land managers throughout the Sierra Nevada to make better decisions on how to manage fire to maintain healthy ecosystems an protect life and property.

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Last Updated: Wednesday, 09-Apr-2003 07:22:49 MDT
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