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Over recent decades, globalization has led to an increase in the international flow of people and goods, bringing people together but also bringing together species that have never coexisted before. Species that are introduced and successfully colonize areas outside their natural ranges are considered ‘invasive’ and can have devastating impacts on species native to the region. Invasive species can cause the decline or extinction of native species, outcompeting them for food, water and space, preying upon them or introducing them to new diseases.

How can an insect that is smaller than a penny cause so much ecological, economic, and cultural devastation? The emerald ash borer, an invasive beetle native to Asia, is one of the most destructive invasive species in North America. These tiny pests killed tens of millions of ash trees in the northeast – and continue to this day.

In Maine, a coalition of Indigenous and non-Indigenous researchers, tribal members, state and federal foresters, conservation groups, and local communities have been working for the past twenty years to prepare for the onset of emerald ash borer in northeastern forests. The group, called the Ash Protection Collaboration Across Wabanakik, is focused on identifying research-informed strategies to protect the future of ash trees.

Note: Complete text of the book by Albert R. Mead (1961. Albert R. Mead. The University of Chicago Press. Chicago. 257 pp.)

Report your catch of invasive fish species (northern snakehead, blue catfish, flathead catfish) in the Chesapeake Watershed for a chance to win great prizes! The Great Chesapeake Invasives Count is an annual angling-based effort (April 1, 2024-March 31, 2025)  to provide important data to the Maryland Department of Natural Resources, USFWS, and other management agencies on what you're seeing on the water. Information related to the number of fish you catch during a given time, as well as the length and weight of the fish you catch is important to fishery managers. It is also vital to investigate the feeding habits of invasive fish to help understand the short and long-term impacts that their existence may cause on native species. It is important that the public recognizes the impacts that these species can have on our natural ecosystems, and does not continue the spread of these fish.

The arid and semiarid Great Basin of the western United States comprises parts of California, Nevada, Utah, Idaho, and Oregon and can variously be described by its hydrology, topography, or biology. Biologically, the area has been defined historically by the native sagebrush and shrubs that thrive in the dry valleys of the Sierra Nevada and Cascade Mountains. But, as a recent study undertaken by researchers at the University of Montana and the Department of Agriculture notes, these native plant communities are rapidly being colonized by nonnative annual grasses like cheatgrass (Bromus tectorum), red brome (B. rubens), and medusahead (Taeniatherum caput-medusae) to the detriment of wildlife and humans.

See also: Publications and Multimedia Catalog for more resources

The purpose of this publication is to alert Oregonians to the risk of introducing or dispersing invasive forest pests through firewood. Although Oregon law restricts the import of untreated commercial firewood, there still is a risk that people moving firewood will introduce or spread pests. Interstate transport of firewood by people is one of the most important avenues for dispersal of many invasive forest pests.
See also: Forest Health, Insects and Disease for more publications.

Invasive grass species can alter fire regimes, converting native terrestrial ecosystems into non-native, grass-dominated landscapes, creating a self-reinforcing cycle of increasing fire activity and flammable grass expansion. Analyses of this phenomenon tend to focus on the ecology and geography of the grass–fire cycle independent of human activities. Yet people introduce non-native grasses to new landscapes (eg via agriculture), facilitate their spread (eg via road networks), and are a primary source of ignition (eg via debris burning). We propose a new framework for this phenomenon that explicitly recognizes the important role of anthropogenic activities in the human–grass–fire cycle. We review links between land use and invasive species as well as ignitions, with a particular focus on the spatial and temporal co-occurrences of these activities to show that these two drivers of wildfires are inextricable. Finally, management strategies that could mitigate impacts are discussed.

Citation: Fusco EJ, et al. 2021. The human–grass–fire cycle: how people and invasives co-occur to drive fire regimes. Frontiers in Ecology and the Environment. 20(2): 117-126.

Although the scientific literature has relatively few publications on the subject, the expanding distribution of ticks and their associated disease-causing pathogens are increasingly shown to be facilitated by the presence of certain invasive plant species, particularly plant understory and transition-zone species. Invasive species have been found to contribute to the spread and survival of ticks, hosts, and various disease-causing pathogens. For those species that have been investigated, several invasive plant species such as Japanese honeysuckle and barberry have been definitively shown to harbor and enhance tick, host, and pathogen populations by enhancing microhabitat and survival. Additionally, non-native tick species such as Asian longhorn tick have been introduced and potentially new invasive tick-borne pathogens or hosts can, and likely will, be introduced in the future. For more publications, see ISAC White Papers.

USDA Forest Service scientists are exploring the impacts of invasive species in forests and rangelands of the United States and developing early intervention strategies that land managers can take as well as strategies for restoring impacted landscapes.

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While ballast water has been a major way species have entered the Great Lakes, it hasn't been the only way.

The fungus behind white-nose syndrome, a disease that has devastated bat populations in North America, may have an Achilles' heel: UV light, according to a study conducted by the Forest Service and its partners.

"White-nose syndrome is the single biggest threat to many North American bat species and one of the most pressing conservation challenges facing America’s wildlife today. Investing in defeating WNS must be a priority, and the results from this study and contributing research give us hope that we can develop the tools to more effectively manage the fungus that causes the disease."

See also: Citrus Insect Pests for more factsheets