The USGS develops strategies and techniques to understand and facilitate restoration of native species and habitats affected by invasive species. This is critical because control without restoration can leave the ecosystem vulnerable to subsequent reinvasion by the same or additional invasive species.
Restoration of ecological systems in wildland areas often involves restoring species to habitats degraded by invasive plant and animal species. Often, such invasive species exert community level impacts, such as direct competition, but may also alter ecosystem function. Restoration cannot be achieved without understanding invasive species dynamics, and their impacts. It is also crucial to understand how to best re-introduce native species to the ecosystem in an efficient, cost-effective manner.
Millions of acres of shrub-grassland ecosystems are in need of restoration in the western United States. For lands degraded by invasive annual grasses, we have been studying best management practices for restoring ecosystem function through using either native or introduced plant species.
Tallgrass prairie is one of the most imperiled ecosystems on Earth, and nowhere more so than in the upper Midwestern United States. The persistence of tallgrass prairie, and the species it supports, are increasingly dependent on management actions to restore and reconstruct native prairie plant communities.
Island habitat off California is ecologically important and extremely vulnerable to disturbance. We are working to re-establish a diverse, native floral community on Scorpion Rock, a small Islet off Santa Cruz Island in the California Channel Islands National Park. Invasive plants (primarily crystalline iceplant Mesembryanthemum crystallinum) once had the upper hand on Scorpion.
Seagrass meadows are ecologically important habitats that are declining globally at an accelerating rate due to natural and anthropogenic stressors. Their decline is a serious concern as this habitat provides many ecosystem services. Eelgrass (Zostera marina) is the dominant seagrass species in the western North Atlantic. It has recently been established that invasive tunicate species possibly threaten the health of eelgrass beds.
Invasive plants, such as Phragmites australis, can profoundly affect channel environments of large rivers by stabilizing sediments and altering water flows. Invasive plant removal is considered necessary where restoration of dynamic channels is needed to provide critical habitat for species of conservation concern. However, these programs are widely reported to be inefficient. Post-control reinvasion is frequent, suggesting increased attention is needed to prevent seed regeneration.
Following eradication of invasive American Bullfrogs (Lithobates catesbeianus) from most of Buenos Aires National Wildlife Refuge (BANWR; Arizona, United States), larval Chiricahua Leopard Frogs (Lithobates chiricahuensis) from a private pond were reintroduced into three stock ponds. Populations became established at all three reintroduction sites followed by colonization of neighboring ponds in subsequent years. Our aim was to better understand colonization patterns by the federally threatened L. chiricahuensis which could help inform other reintroduction efforts.
Top Photo: Phragmites line a marsh at Sachuest Point. Photo courtesy of Tom Sturm, U.S. Fish and Wildlife Service.