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Managers often struggle to calculate the ecological and economic costs associated with invasive species. Yet, knowing these impacts can boost support and understanding for invasive species management. In a new book chapter, NWRC economist Dr. Stephanie Shwiff and colleagues describe how economists determine costs of both primary and secondary impacts from invasive species and how these translate into jobs and revenue in regional economies.

The Environmental Impact Classification for Alien Taxa (EICAT) is the IUCN global standard for measuring the severity of environmental impacts caused by animals, fungi and plants living outside their natural range. This tool alerts scientists, conservation practitioners and policy makers to the potential consequences of alien species, guides the development of prevention and mitigation measures, and assists in the prioritisation of management actions.

You cannot protect the environment without also safeguarding plant health. When plant pests and diseases spread into new areas they seriously damage entire ecosystems, putting at risk biological diversity and the environment itself. Tiny and lethal at the same time, plant pests and invasive alien species have been recently identified as the main driver of biodiversity loss. Pests are also responsible for losses of up to USD 220 billion in agricultural trade each year and the loss of 40 percent of the global food crop production. Climate change is making the situation even worse. It is changing the life cycle of pests – sometimes increasing the number of yearly generations - and creating new niches where they can thrive. For more information see the IPPC factsheet "Plant Health and Environmental Protection [PDF, 1.22 MB]".

Garlic mustard (Alliaria petiolate) is a highly destructive invader in North America. As well as hindering the survival of native plants, it poses a particular threat to the survival of the rare West Virginia white butterfly (Pieris virginiensis).

Grass carp, one of four species of Asian carp, has the potential to disrupt the Great Lakes ecosystem and economy unless their spread is stopped, according to a report released by Fisheries and Oceans Canada with support from the Great Lakes Fishery Commission and the Ontario Ministry of Natural Resources and Forestry. The socio-economic study concludes that, in addition to the significant ecological threat that is posed by the presence of grass carp in the Great Lakes, there would also be economic, social and cultural ripple effects.
See also: Full report for the Socio-Economic Risk Assessment of the Presence of Grass Carp in the Great Lakes Basin [PDF, 1.34 MB].

In 2016 NASS began to collect data on honey bee health and pollination costs. Provides reliable, up-to-date statistics help track honey bee mortality.

Scientists from the CNRS, the IRD, and the Muséum National d’Histoire Naturelle have just released the most comprehensive estimate to date of the financial toll of invasive species: nearly $1.3 trillion over four decades. Published in Nature (31 March 2021), their findings are based on the InvaCost database, which is financed by the BNP Paribas Foundation and the Paris-Saclay University Foundation’s AXA Chair of Invasion Biology. The annual expenses generated by biological invasions are only increasing, with no sign of any slowing.

Nile perch were introduced to Lake Victoria in the 1950s to boost the fishing industry. The introduction of Nile perch caused an economic boom, but almost caused cichlids, a native fish, to go extinct. Discover the role an invasive species can play in an ecosystem and social system.

See also: NOAA Aquatic Invasive Species Fact Sheet - Invasive Lionfish [PDF, 1.46 MB]

InvaCost is the most up-to-date, comprehensive, standardized and robust data compilation and description of economic cost estimates associated with invasive species worldwide. InvaCost has been constructed to provide a contemporary and freely available repository of monetary impacts that can be relevant for both research and evidence-based policy making.

CABI scientists have conducted the first comprehensive study on the economic impact of a range of Invasive Alien Species (IAS) on Africa's agricultural sector, which they estimated to be USD $3.6 trillion a year. This is equivalent to 1.5 times the Gross Domestic Product (GDP) of all African countries combined – or similar to that of Germany. The average annual cost of IAS per country was USD $76.32 billion. Full details of the cost for individual countries are outlined in the paper published in the journal CABI Agriculture and Bioscience.

European green crabs are one of the most widespread invasive marine species on the planet, originally reaching Washington in 1996. When green crab populations grow too large, they compete with other shellfish, disturb the sediment, and destroy the eelgrass that is an important habitat for Dungeness crab and salmon. The U.S. Geological Survey (USGS) is working to increase the effectiveness of Washington’s green crab early detection and rapid response program. Research conducted at the USGS' Western Fisheries Research Center aims to improve native shellfish habitat and limit the spread of European green crabs in coastal waters.

The invasive Asian jumping worm (Amynthas agrestis) has many common names: Alabama jumpers, Jersey wrigglers, wood eel, crazy worms, snake worms, and crazy snake worms. “Invasive Asian jumping worms got their name because of the way they thrash around,” said Mac Callaham, a Forest Service researcher who specializes in soils. “They can flip themselves a foot off the ground.”

Like other earthworms, Asian jumping worms eat tiny pieces of fallen leaves. But there’s a problem. Those fallen leaves make up the top layer of forest soil. The litter layer, as it’s called, is home to a vast number of tiny animals. Many plants can’t grow or spread without the layer of leaf litter. “Soil is the foundation of life – and Asian jumping worms change it,” says Callaham. “In fact, earthworms can have such huge impacts that they’re able to actually reengineer the ecosystems around them.”