- Home
- About SRWP
- Watershed Blog
- Explore the Watershed
- Sacramento River Watershed Data Portal
- Forest Health
- A Roadmap to Watershed Management
- Introduction
- Sacramento River Basin
- Sacramento River Basin Watersheds
- Water Quality Monitoring in the Sacramento River Basin
- Measuring the Health in the Sacramento River Basin
- Watershed Projects - Leading the Way
- Antelope Creek Watershed Stewardship - Lassen National Forest
- Battle Creek Restoration Project
- Bear Creek Meadow Restoration
- Bear River Setback Levee Project
- Cooperative Sagebrush Steppe Initiative - Butte Creek Project
- Cow Creek - Bassett Diversion Fish Passage Project
- HFQLG Forest Recovery Act, Pilot Project
- Hamilton City Levee Setback
- Iron Mountain Mine Superfund Cleanup
- Lassen Creek Stream and Meadow Restoration
- Lower American River Sunrise Side Channel Project
- Lower Clear Creek Floodway Rehabilitation
- Pit River Channel Erosion
- Red Bluff Diversion Dam Fish Passage Improvement
- Red Clover Creek Restoration Project
- Redding Allied Stream Team
- Sunflower Coordinated Resource Management Program
- Photo and Contributor Credits
- Resources
- Roadmap Videos
- Conservation on Cache Creek
- Fixing Incised Creek Banks on the Feather River
- Flooding On The Sacramento River
- Google Earth Tour of Butte Creek
- Google Earth Tour of Cache Creek
- Google Earth Tour of the Feather River
- Google Tour of Northeast Subregion
- Google Tour of the American River Watershed and Truckee Watershed
- Google Tour of the Sacramento Mainstem
- Helicopter flight up the American River
- Resource Conservation in the Pit River watershed
- Restoring Fish Habitat on the Feather River
- Spring Run Salmon in Butte Creek
- Watershed work on the mainstem of the Sacramento River
- Wildfire Management in the Sacramento Watershed
- Sacramento River Basin Report Card
- Cover and Acknowledgements
- Table of Contents
- List of Acronyms
- Executive Summary and Report Card
- 1.0 Introduction and Background
- 2.0 Indicator Selection
- 3.0 Indicator Generation, Evaluation, Aggregation
- 4.0 General Methods and Principles
- 4.1. Reporting and analysis subwatershed units
- 4.2 Scoring: Distance to target/reference and scoring transformations
- 4.3 Trend/time series analysis
- 4.4 Confidence in Report Card findings
- 4.5 Spatial scale and aggregation of fine scale data to subwatershed
- 4.6 Temporal scale and aggregation
- 4.7 Cross-indicator score aggregation
- 4.8 Data management and transformation
- 5.0 Interpretation
- 6.0 Conclusions and Recommendations
- Appendix A: Glossary of Terms
- Appendix B: Indicator Selection Criteria
- Climate Change / Drought
- Flooding
- Invasive Plants
- Background on Invasive Plants
- Invasive Plants of the Sacramento River Watershed
- Invasive Plant Organizations
- Weed Management Areas
- Butte WMA
- Colusa, Glenn and Tehama WMA
- El Dorado County Invasive Weed Management Group
- Lake WMA
- Lassen County Noxious Weed SWAT Team
- Modoc WMA
- Napa County WMA
- Nevada/Placer WMA
- Plumas/Sierra Noxious WMA
- Sacramento WMA
- School Based Watershed Education - Upper Feather River
- Shasta WMA
- Siskiyou WMA
- Solano WMA
- Yolo WMA
- Yuba/Sutter WMA
- County Agriculture Departments
- Resource Conservation Districts
- State and Federal Agencies
- Non-Governmental Organizations
- Weed Management Areas
- Resources
- Invasive Plant Mapping
- Projects
- Responsible Landscaping
- On-Line Regulatory Permitting Guide
- Rural Residential Development
- Mercury
- Events
- Our Work
- News
Background on Invasive Plants
Water hyacinth (Eichhornia crassipes) and other aquatic weeds have significant impact on wildlife, recreation, and water conveyance, especially in the Sacramento River Delta (Photo: Bob Case)
Invasive species are widely recognized as a top threat to healthy ecosystems and economies. In California, invasive plants impact farming, ranching and timber operations; hunting, fishing, boating, and hiking opportunities; water supply and delivery; flooding and wildfire damage; and native plant and wildlife species.
What Makes a Plant "Invasive"?
When plants that evolved in one region of the globe are moved by humans to another region, a few of them flourish, crowding out native vegetation and the wildlife that feeds on it. Some invasives can even change ecosystem processes such as hydrology, fire regimes, and soil chemistry. These invasive plants have a competitive advantage because they are no longer controlled by their natural predators, and can quickly spread out of control. In California, approximately 3% of the plant species growing in the wild are considered invasive, but they inhabit a much greater proportion of the landscape.
Who Lists Invasive Plants?
Invasive plants are defined by the California Invasive Plant Council (Cal-IPC) as plants that grow wild and cause damage in a region where they are not native. These plants are listed in their Inventory.
The California Department of Food and Agriculture (CDFA) maintains a list of "noxious weeds" that are subject to regulation or quarantine by county agricultural departments. For more information, see CDFA's Integrated Pest Control Branch. These weeds are typically agricultural pests, though many also have impacts on natural areas.
Impacts
Invasive plants cause a variety of problems. Aquatic species can form dense mats that kill aquatic life, impede recreation, and keep migratory birds from landing. Some plants increase the danger of wildfires by creating greater fuel loads than native species. Others lower water tables by using significantly more water than native plants. Some alter soil chemistry by exuding salts, or fixing nitrogen. And most invasive plants displace native plants that support wildlife.
How Do They Get Here?
Invasive plants reach California by many pathways. Some are attractive and are introduced as ornamentals. Others came with early settlers as forage species for livestock. Still others were accidental introductions or contaminants in shipments of seed or hay.
What’s Being Done?
Due to the wide-ranging impacts of invasive plants, many organizations and individual citizens now work to protect and restore native habitats by removing invasive plants. These “weed workers” range from professional land managers employed by government agencies, to local landowners, to volunteers spending their weekends working in local parks or creeks. The resources in these web pages support this growing effort to address invasive plants.
