Wildlife Action Plan
- Introduction
- Final Plan
- Final Plan in Spanish
- Matrix Overview
- Wildlife Species Matrix
- Wildlife Monitoring Survey
Statewide Topics
- Natural Diversity
- Species at Risk
- Stressors
- Conservation Actions
- Monitoring
- Conservation Capabilities
Regional Diversity
Information Sources
Workshop Results
Other DFG Programs
- Environmental Review & Permitting
- Conservation Planning
- Resource Assessment
- Biogeographic Information & Observation System (BIOS)
Action Plan Partner
Wildlife Action Plan
1812 9th Street,
Sacramento, CA 95811
WAP - Stressors
The regional chapters describe the problems and threats that may adversely affect wildlife and their habitats. These threats are termed "stressors." In each region of the state, there are multiple stressors to wildlife and habitats, operating alone and in combination. A number of these stressors are common to the entire state or to several different regions. Growth and development, water management conflicts, invasive species, and climate change each have major consequences for species, ecosystems, and habitats in every region of the state.
Growth and development
Statewide, California's population grew by 49 percent between 1970 and 1990 and again by nearly 14 percent adding over 4 million residents between 1990 and 2000. Increasing needs for housing, services, transportation, and other infrastructure have placed ever-greater demands on the state's land, water, and other natural resources. Without conservation planning, growth and development can eliminate important habitats and fragment and decrease the quality of remaining natural areas. With the exception the Modoc Plateau, development represents a substantial stressor for species and habitats across the state.
Water management conflicts
Across all regions of the state, limited water resources are managed to meet water and power supply needs and to accommodate residential and agricultural land use. Water management activities include the operation of dams and diversions; development and operation of irrigation canal systems; extraction of groundwater; and construction of flood-control projects like levees and channelization. These activities can reduce the amount of water available for fish and wildlife, obstruct fish passage, and result in numerous other habitat alterations. In all regions of the state, aquatic and riparian habitats support rich biological communities, including many special status species, and degradation of these habitats represents a serious threat to the state's biological heritage.
Invasive species
Since the arrival of the first European settlers in California, non-native species have been introduced both unintentionally and purposefully to the state. At present, more than 1,000 introduced plant species and more than 110 non-native fish and wildlife species inhabit California. Among these non-native species, those that disrupt or alter native ecological communities and have negative consequences for native species and habitats are considered to be invasive. In many habitats, invasive plants outcompete native species for light, water, and soil. These plants may also offer inferior habitat and nutritional values for native animal species and sometimes alter ecosystem processes, such as natural fire regimes. Invasive animals outcompete, prey upon, or disturb the habitat of native wildlife and may spread diseases.
Climate Change
Climate change will affect ecological communities and wildlife species throughout California. Current climate models predict overall temperature increases of between 4 degrees and 10.5 degrees Fahrenheit by the end of the century, accompanied by hotter, drier summers and warmer, wetter winters.
Rising temperatures and altered precipitation patterns will result in changes in plant communities and reduced habitat suitability for some wildlife species. Some communities and species may shift to higher elevations or latitudes, but this will become ever more challenging as remaining natural areas shrink and the gaps between habitats grow. Throughout the state, drier summers may also increase fire frequency and intensity. Climate change effects will be especially disruptive in the Sierra Nevada and Cascades and Central Valley and Bay-Delta regions.
Other widespread stressors
A number of other stressors also recur in multiple regions. Excessive livestock grazing, either in sensitive habitats or grazing of too many animals or for too long a grazing period, significantly affects wildlife habitats in the Mojave Desert, Central Coast, North Coast-Klamath, Modoc Plateau, and Sierra Nevada and Cascades regions. Forest management conflicts are major stressors in the North Coast-Klamath, Modoc Plateau, and Sierra Nevada and Cascades regions. Altered fire regimes were identified as major stressors in the South Coast, North Coast-Klamath, Modoc Plateau, and Sierra Nevada and Cascades regions. Pollution and urban or agricultural runoff were identified as major stressors in the South Coast, Central Coast, Central Valley and Bay-Delta, and Marine regions. Recreational pressures and human disturbance are issues in the Mojave Desert, Colorado Desert, South Coast, Central Coast, Sierra Nevada and Cascades, and Marine regions.