Pacific Southwest Research Station

Climate variability and change has broad effects on physical and ecological attributes of ecosystem composition, structure, and function at many temporal and spatial scales. PSW research units and scientists excel in studies that investigate relationships of ecosystems and driving natural and anthropogenic forces, including climate.

Ongoing Research:

Vegetation Response to Climate Change

• Climate and Landscape Change Contact: Connie Millar, cmillar@fs.fed.us

High mountain systems, such as the Sierra Nevada, are uniquely sensitive to anticipated global climate changes and act as "canaries in the coal mine" to provide early signals of significant climate-driven changes. Research in the Sierra Nevada by PSW scientists shows how vegetation has responded to climate in the past and indicates changes that might be coming in the future.

• Regional Climate Variability and High-Elevation Forest Response Over the Past 4000 Years
• Medieval Forests, Volcanism, and Response to Climate
• Rock Glaciers and Periglacial Rock-Ice Features in the Sierra Nevada
• Response of Subalpine Conifers to 20th Century Climate Variability in the Sierra Nevada
• Quaternary Biogeography of Pacific Southwest Tree Species
• 1000 Years of Forest History in the Glass Creek Watershed, Eastern Sierra Nevada


• Forest Function and Health
• Conservation of Biological Diversity
• Forested Wetlands on Pacific Islands
• Invasive Species in Hawaii
• Disturbance Processes
• Biodiversity and Conservation Genetics

Wildlife Response to Climate Change

• Herpetology - California Coast Ranges (Contact Hart Welsh) and Sierra Nevada (Contacts: Amy Lind and Kathleen Matthews)

Amphibian and reptile populations respond strongly to changes and variability in air and water temperature, precipitation, and the hydroperiod of their environments. Over the short-term (e.g. annually), these factors can determine reproductive success rates and survival to metamorphosis. Over the long term, the frequency and duration of extreme temperature and precipitation events can influence the persistence of populations and the overall structure of meta-populations on the landscape. Amphibian research at PSW includes work on high elevation species that may be especially vulnerable to predicted climate warming, such as mountain yellow-legged frogs and Yosemite toads. Species like the foothill yellow-legged frog and western pond turtle that inhabit riverine environments, especially in regulated (dammed) systems are also vulnerable to projected variability in the timing and amount of precipitation. Research on amphibians includes development of restoration techniques which could be used to enhance populations in areas that may be less impacted by climate change.

• Impacts of year-year variations of precipitation (snowpack and rainfall) on amphibian recruitment and survival
• Seasonal habitat use and site fidelity of the mountain yellow-legged frog in Sierra Nevada high-elevation lakes
• Multi-scale environmental relationships and population status of lentic-associated amphibians in the Lake Tahoe basin
• Amphibian assemblages and introduced fishes in the wilderness areas of the Klamath-Siskiyou bioregion
• Aseasonal pulsed flow effects on the foothill yellow-legged frog (Rana boylii): Integration of empirical, experimental and hydrodynamic modeling approaches
• Effects of damming on two herpetofaunal species of a riverine ecosystem
• Reproductive ecology of the foothill yellow-legged frog (Rana boylii) in Hurdygurdy Creek, northwestern California: implications for species conservation and management
• Reintroduction of declining amphibians: a case study for the foothill yellow-legged frog (Rana boylii) and development of a quantitative database


• Marbeled Murrelet and Landbird Monitoring
• Carnivore Survey and Monitoring

Insect and Disease Response to Climate Change

• Forest Disease (Contact: Susan Frankel, sfrankel@fs.fed.us) Sudden Oak Death

Forest plant diseases are heavily influenced by weather and climate. For forest pathogenic fungi, bacteria, viruses and other microorganisms, the temperature and moisture conditions interacting with the host determine infection severity and disease distribution. Extreme weather, i.e. drought or typhoons, can kill large expanses of trees directly by overwhelming tree physiological and structural strength. Patterns and rates of wood decay, caused by forest fungi, are also expected to change in response to climate changes which will influence forest carbon cycles. Expected changes in climate coupled with the increasing stresses of invasive species, lack of fire, and forest fragmentation are creating conducive conditions for many forest plant diseases.

• Kliejunas, J. T.; Geils, B.; Glaeser, J. M.; Goheen, E. M.; Hennon, P.; Mee-Sook K.; Kope, H.; Stone, J.; Sturrock, R. and Frankel, S.J. In preparation. Climate and Forest Diseases of Western North America: A Literature Review. September 24, 2008. General Technical Report. PSW-GTR-XXX. USDA Forest Service, Pacific Southwest Research Station, Albany. 36 p.
• Searchable annotated bibliography of Climate and Forest Diseases of Western North America

Physical Environment Response to Climate Change

• Water and Watershed Processes
• Kings River Experimental Watershed
• Air Pollutants and Ecosystem Impacts
• Caspar Creek Watershed Study

Research is conducted by:

• Sierra Nevada Research Center (RWU-4202)
• Ecology and Management of Western Forests Influenced by Mediterranean Climate (RWU-4155)
• Air Pollution and Global Change Impacts on Western Forest Ecosystems (RWU-4451)
• Cumulative Effects of Forest Mgmt on Hillslope Processes, Fishery Resources, and Downstream Environments (RWU-4351)
• Institute of Forest Genetics (RWU-4103)
• Institute of Pacific Islands Forestry (RWU-4154)
• Sudden Oak Death Research
  Phytophthora ramorum SOD
• Maintaining Faunal Diversity in Forested Ecosystems of the Coastal and Intermountain West (RWU-4251)