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Aquatic invasive species pose an ongoing threat to the environment, economy, recreation, and human health and safely. These species are a direct driver of biodiversity loss, yet also hinder economic development, serve as vectors of disease, decrease the aesthetic value of nature, and prevent recreational activities. Keep reading to learn more about these specific threats.

The financial cost of non-native species has been published in a new report. "The Economic Cost of Invasive Non-Native Species (INNS) to the British Economy" suggests that invasive species cost 1.7 billion pounds every year. The research was conducted by the international scientific organization CABI for the Scottish Government, Defra and the Welsh Assembly Government and breaks down the effect on each country. It indicates that the economic cost of INNS can be wide ranging and can result in the loss of crops, ecosystems and livelihoods. The cost to the agriculture and horticulture sector alone is estimated to be 1 billion pounds across Britain.
See also: Publications - Non-native species impacts for related information.

Prepared for the Oregon Invasive Species Council.

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.

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.

The purpose of this report is to raise awareness among key stakeholders, decision-makers, policymakers and the general public about the environmental and socioeconomic impacts of IAS. Twenty-eight dedicated species accounts are provided to highlight the various types of impacts. These species accounts are based on thorough, up-to-date scientific information from recent research and studies, and highlight the multifaceted impacts of IAS at both the global and regional levels.

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.

Nonnative tree species are gaining a foothold in forest ecosystems. These trees compete with native species for resources, sunlight, and space. Tree of heaven and Chinese tallow tree are the most invasive tree species in the South, according to a recent study which uses Forest Inventory & Analysis data to create an indicator of nonnative tree regeneration success and can help prioritize the species and locations for treatment. 

The U.S. Fish and Wildlife Service announced a final rule to reclassify the northern long-eared bat as endangered under the Endangered Species Act (ESA). The bat, listed as threatened in 2015, now faces extinction due to the rangewide impacts of white-nose syndrome, a deadly disease affecting hibernating bats across North America. The rule takes effect on January 30, 2023.

This guide will assist Pacific island practitioners to use the costs that result from invasive species incursions to gain support to fund prevention, management, restoration, research, and outreach. For more knowledge resources, please visit the Pacific Battler Resource Base.

White-nose syndrome has killed over 90% of northern long-eared, little brown and tri-colored bat populations in fewer than 10 years, according to a new study published in Conservation Biology. Researchers also noted declines in Indiana bat and big brown bat populations. The findings, detailed in "The scope and severity of white-nose syndrome on hibernating bats in North America," underscore the devastating impacts of the deadly fungal disease. The research tapped into the most comprehensive data set on North American bat populations to date, which includes data from over 200 locations in 27 states and two Canadian provinces.