USDA Forest Service

Pacific Southwest Research Station

Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Research Topics Ecosystem Processes

Sierra Nevada Ecosystems

Conservation of Biological Diversity

The worldwide loss of biological diversity continues, largely in response to widespread habitat destruction, over-harvesting, pollution, and the accidental or otherwise inappropriate introduction of foreign plants and animals. Thus, to conserve the biological diversity of the Sierra Nevada it will be crucial to identify the vulnerable components of biological diversity, determine the threats to diversity, understand the response of organisms and ecosystems to the threats, determine restoration and recovery techniques, perform adaptive management projects, and monitor recovery.

To protect and maintain biological diversity we must understand how management activities and natural environmental changes affect species and their habitats, work to conserve and protect species that remain viable, and restore species in trouble. Research at the SNRC focuses on the response of populations and communities of aquatic and riparian-associated species to natural and anthropogenic influences, such as introduced exotic species, natural and regulated stream flow regimes, livestock grazing, natural and prescribed fire, and vegetation management.

Subproblem 1: Determine ecological responses of aquatic and ecosystems to anthropogenic (human-induced) and natural environmental changes

photo of a lakeResponses of aquatic, riparian, and wetland systems to natural and anthropogenic influences (e.g., fire, flood, drought, climate variation, fuels management, silviculture, livestock grazing, invasive species, dams and diversions) will be studied to provide information for conserving the biological diversity of Sierra Nevada aquatic ecosystems. In order to understand various ecological responses, we will also study physical, chemical, and biological interactions under conditions of minimal human-induced disturbance in aquatic, riparian, and wetland systems.

blue arrrowImpacts of invasive species (non-native trout) on native biota of Wilderness lakes, and future restoration strategies for balancing fish stocking and native species

blue arrrowDetermining the Effects of Livestock Grazing on Yosemite Toads (Bufo canorus) and their Habitat: An Adaptive Management Study

blue arrrowAseasonal pulsed flow effects on the foothill yellow-legged frog (Rana boylii): Integration of empirical, experimental and hydrodynamic modeling approaches.

Subproblem 2: Understanding the basic ecology of aquatic organisms in less disturbed habitats

photo of mountain yellow-legged frogBasic understanding of the natural history of species and their relationship toless altered habitats is necessary to gain a comparative understanding of processes in managed and unmanaged environments. If management activities are factors in species declines, understanding how ecosystems and species dynamics operate under natural conditions will be important in designing reserves or other restoration plans. For this reason, some research attention is focused in Sierra Nevada National Parks (Yosemite and Kings Canyon) where less disturbance has occurred historically and some management activities are no longer permitted (cattle grazing, logging, fish stocking, etc.). Research gathered in less disturbed, reference areas provides a scientific basis for future management, conservation, and restoration.

blue arrrowImpacts of year-year variations of precipitation (snowpack and rainfall) on amphibian recruitment and survival

blue arrrow Multi-scale environmental relationships and population status of lentic-associated amphibians in the Lake Tahoe Basin.

blue arrrow Seasonal habitat use and site fidelity of the mountain yellow-legged frog in Sierra Nevada high-elevation lakes

Subproblem 3: Develop aquatic species and ecosystem conservation and restoration techniques and strategies

photo of a lakeIt is widely acknowledged that many aquatic ecosystems are degraded and aquatic species are in decline. New research on the best methods for maintaining, conserving, and, where necessary, restoring the structure, composition, function, and connectivity of aquatic, riparian, and wetland ecosystems and species is needed. Land managers and policy-makers require reliable and defensible science to support restoration activities.

blue arrrow Reintroduction of declining amphibians: a case study for the foothill yellow-legged frog (Rana boylii) and development of a quantitative database.

Subproblem 4: Ecological Response of Terrestrial Species and Ecosystems to Management Activities and Natural Processes

Understanding human-induced effects, especially management activities distinguished from natural variability of ecosystems, on populations and communities of terrestrial species is a primary emphasis of this subproblem. Research in this subarea addresses the direct and indirect effects of such influences on the structure, composition and function of vegetation, the quantity and quality of habitat, and the resulting distribution and abundance of species. Broad areas of inquiry include the effects of fire, both wild and prescribed, fire suppression, vegetation management, grazing, climate change, and recreation on Sierran species and communities. Research activities are crafted in collaboration with land managers to maximize practical learning opportunities.

blue arrrowEffects of Off-Highway Vehicles (OHV) on Vertebrate Communities

blue arrrowEffects of prescribed burning in the spring on avian communities

blue arrrowRole of Urban Forests in Conserving and Restoring Biological Diversity in the Lake Tahoe Basin

blue arrrowLinks between landscape condition and survival and reproduction of fishers in the Kings River Area in the Sierra National Forest

Subproblem 5: Habitat Relationships of Terrestrial Wildlife Species

photo of Pacific-slope flycatcher nestBasic knowledge of natural history and habitat relationships provides the foundation for understanding the reasons behind responses to human-induced and natural influences, determining the conservation status of species, and assessing projected future change in distribution and abundance. Research in this subproblem emphasizes species-habitat relationships, estimation of important population ecology parameters, and the development of models to predict species occurrence and demographic performance. Possible models range in specificity from habitat suitability models developed from presence-absence data that predict the suitability of a site for occupancy by a species to more detailed models that address habitat quality as determined by relationships among vegetation structure and composition and species survival, reproduction, and dispersal. Habitat models are developed at multiple spatial scales ranging from the plot scale to the larger home range and landscape scales using combinations of vegetation plot data, environmental data, and remotely sensed data.

blue arrrowAbundance, distribution, and population trends of oak woodland birds

blue arrrowDevelopment and Evaluation of Tools for Monitoring Ecosystem and Species Diversity across Landscapes

blue arrrowPatterns of biodiversity, abundance and productivity of forest birds over an elevational gradient

Subproblem 6: Biodiversity Conservation and Restoration

photo of male spotted owlInquiry in this sub-area focuses on a broad array of issues related to the conservation and specifically restoration of biodiversity in the Sierra Nevada. Basic and applied research covers topics such as risk assessment, ecological monitoring, identification of focal species, population dynamics and viability assessment, community structure and function, habitat conservation planning, vertebrate community monitoring methods, and species and habitat restoration. Research in this subarea spans multiple spatial and temporal scales and is typically multi-disciplinary in nature, integrating landscape/ecosystem pattern and processes with ecological and socio-economic factors in the development of methods, techniques, and models for managing, conserving, and restoring biodiversity in the Sierra Nevada.

blue arrrowNorthern Goshawk: Habitat Conservation Assessment for California

blue arrrowWest Nile Virus in Spotted Owls, Great Gray Owls, and Northern Goshawks: Health Assessment, Antibody Levels, and Genetics

Last Modified: Aug 29, 2016 10:56:03 AM