Sustain Our Nation's Forests and Grasslands

A brief overview on invasive species in the Forest Service

Invasive plants are a major threat to our nation’s forests and grasslands. Thousands of acres are infested annually, threatening the ecological integrity and biological diversity of our forest ecosystems and resulting in significant negative economic impacts. The establishment and spread of invasive plants can displace native species, replace native plant communities and alter ecosystem processes, including soil deposition and erosion, hydrologic cycles, nutrient cycling and fire regimes. The result can be loss and destruction of forage and habitat for wildlife, loss of available grazing land, diminished land values, lost forest productivity, reduced groundwater levels, soil degradation, increased risk of devastating wildfires and diminished recreational enjoyment. 

Sage-Grouse on the Curlew Grassland, Caribou-Targhee National Forest
Sage-Grouse on the Curlew Grassland, Caribou-Targhee National Forest

Ongoing Forest Service efforts to protect critical sagebrush habitat across 11 states in the western United States for greater sage-grouse (Centrocercus urophasianus) illustrates the negative impacts invasive species can have on our nation’s forests and grasslands. The introduction, establishment and spread of invasive annual grasses such as cheatgrass (Bromus tectorum) and medusahead (Taeniatherum caput-medusae) has converted the native perennial-dominated sagebrush ecosystems to invasive annual grasslands. Additionally, invasive perennial forbs such as Russian knapweed (Acroptilon repens) and Dalmatian toadflax (Linaria dalmatica) have established in these landscapes, changing the native species composition and resulting in altered wildfire cycles. These changes also lead to diminished quality of greater sage-grouse habitats.

Cheatgrass (Bromus tectorum)
Cheatgrass (Bromus tectorum)

To address this issue, the Forest Service has employed a multifaceted approach utilizing the strengths of three of its main branches: Research and Development, National Forest System and State and Private Forestry. Since the mid-1980s, Research and Development has made key strides toward understanding and managing sage-grouse populations and habitats, understanding disturbances and stressors in sagebrush ecosystems (e.g., cheatgrass invasions), and developing methods, models and plant materials to restore these disturbed habitats. Much of this work is conducted on National Forest System lands, and National Forest System has been instrumental in the planning and coordination of management and conservation activities. State and Private Forestry works with states and local, multi-jurisdictional organizations (e.g., Cooperative Weed Management Areas) to provide expertise and technical support for the implementation of weed management strategies.

Three sage-grouse in the snow on the Curlew National Grassland. Caribou-Targhee National Forest.
Sage-Grouse on the Curlew National Grassland. Caribou-Targhee National Forest.

Preventing, detecting, monitoring and managing invasive species and restoring ecosystems affected by these organisms is an immense and continuous task that requires collective efforts from local, state and federal agencies as well as community support. The Forest Service’s approach to invasive species prevention, management and restoration through cooperative efforts within and across organizational boundaries is a model for collaboration and illustrates its commitment to this important, worldwide issue.

 

Vanessa M. Lopez, Acting Invasive Plants Program Manager, State and Private Forestry, Forest Health Protection, Washington Office and Melissa L. Jenkins, Natural Resources Specialist, Cooperative Forestry, Forest Service Wood Innovations, State & Private Forestry, Washington Office