Invasive Species

Fire has had a very different influence on the forests and shrublands of California. Unlike the case in many forests where fires have been excluded for over a century, shrublands throughout the state have experienced the opposite impact. Invasive grasses that burn more readily than native plants have increased the frequency of wildfires in southern California shrublands. As fire clears swathes of...

Desert landscapes are rapidly changing due to increases in invasive plant species, frequency of wildfires, urban and energy development, recreational use, military training, and climate variation. Dr. Todd Esque, USGS researchers, and collaborators are working together to investigate these changes and provide managers with key information that can be used to manage natural resources more...

The desert tortoise is listed as “threatened” under the Endangered Species Act. USGS WERC scientists, along with project partners have been conducting long-term analyses on how changes in the southwestern deserts of the United States can affect desert tortoise populations. Dr. Todd Esque and his team are investigating how habitat disturbances and restoration projects influence tortoise populations...

Surface disturbances ranging from military training, recreation, energy exploration and development, and wildfires impact a large majority of federal lands in the western US, but the ecological and economic impacts are poorly understood. Explore this webpage to learn how Dr. Lesley DeFalco and her research team are currently evaluating and refining conventional approaches for post-fire restoration...

Fuel conditions and fire regimes in western forests and deserts have been altered due to past land management, biological invasions, and recent extreme weather events and climate shifts. These changes have created extreme fire risk to local and regional communities, threatening their economic health related to wildland recreation, forest production, livestock operations, and other uses of public...

The terrestrial biota of the Central Pacific is primarily defined by its degree of isolation. At the center lies the Hawaiian Archipelago, which is more than 3,200 km from any continental land mass. After tens of millions of years of evolutionary isolation from all mammals except bats, islands of the Central Pacific were quite suddenly besieged by a number of alien rodents, carnivores and both...

The maculata apple snail (Pomacea maculata) has invaded many coastal and some inland areas in south Louisiana. Reports have indicated that the freshwater snails have significantly reduced the amount of submerged aquatic vegetation (SAV) and floating leaved vegetation (FLV) available for waterfowl and other wildlife.

Biological production represents the total amount of living material (biomass) that was produced during a defined period of time. This production is important because some of it is used for food and some is valued for recreation, it is a direct measure of total ecosystem processes, and it sustains biological diversity. Production is a measure of energy flow, and is therefore a natural currency for...

Islands and atolls throughout the Pacific have been impacted by invasive ant species. Threatening native ants and other arthropods with their aggressive behavior and ability to colonize large geographic areas, invasive ants pose one of the most serious threats to island ecosystems. This project focuses on three areas of the Pacific: American Samoa, Rose Atoll, and Johnston Atoll.

Six species of biting mosquitoes have been introduced to the Hawaiian Islands since Western contact, two of which are vectors of dengue, chikungunya, and Zika viruses. Environmental conditions favorable for the transmission of dengue and Zika occur year-long across Hawai‘i’s coastline. To better understand the ecology of vector mosquitoes and support public health efforts, mosquito monitoring at...

The Greater Sage-grouse is a small bird found only in the sagebrush steppe of the Great Basin. Invasions of non-native grasses, evolving wildfire patterns, grazing from livestock, and human land uses are changing this unique ecosystem. WERC’s Dr. Pete Coates studies sage-grouse populations to determine how these influences could affect the bird and other wildlife in the future.

Both wildlife and human health in Hawai‘i and other island ecosystems in the Pacific Basin face continued threats from introductions of diseases and vectors. Accidental introduction of mosquito-borne avian malaria and pox virus to Hawai‘i is an outstanding example of how biological invasions can have a profound effect on endemic wildlife. The geographic distribution, density, and community...