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The yield losses attributed to Asian citrus greening disease once established can be devastating. If the disease continues to spread unabated in the citrus growing regions of East Africa, the annual value of lost production could potentially reach up to US $127 million over the next ten to 15 years, according to a recent paper published by CABI. The paper, The Asian Citrus Greening Disease (Huanglongbing): Evidence Note on Invasiveness and Potential Economic Impacts for East Africa (Jun 2021) [PDF, 2.9 MB], provides a review of the global literature on Asian citrus disease or huanglongbing (HLB) and estimates its potential economic impact on East Africa. The paper also makes recommendations for biosecurity preparedness, surveillance and management options to help decision-makers and citrus growers.

See in particular Chapter 3: Freshwater, Wetlands, Biodiversity and Human Health, section 5.1 "Aquatic Invasive Alien Species" and Chapter 7: Infectious Diseases, section 2.3.4 "Implications of Biotic Exchange (Invasive Alien Species)".

To date no studies have been undertaken on the costs and benefits of IAS management in the Caribbean. This may partly explain why there has been negligible funding to combat the onslaught of these exotic species in the region. As a result it was decided to provide individuals involved in the UNEP-GEF Project, "Mitigating the Threats of Invasive Alien Species in the Insular Caribbean" with training and an opportunity to undertake Cost-Benefit Analyses (CBAs) on some selected IAS. The CBAs undertaken and reported in this publication clearly demonstrates that the benefits of managing IAS outweigh the costs.

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).

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.

See the people and communities from around the world who are affected by invasive species.

A desire to avoid more extinctions is one of the drivers behind new research by the Threatened Species Recovery Hub which has identified invasive species as the no. 1 threat to Australian biodiversity with habitat loss a close second.

The Mediterranean Sea is being invaded by hundreds of fish, jellyfish, prawns and other marine species from outside the region. More than 1 000 non-indigenous species have been identified in the Mediterranean and the Black Sea. Over half have established permanent populations and are spreading, causing concern about the threat they pose to marine ecosystems and local fishing communities.

“Climate change and human activities have had a profound impact on the Mediterranean and the Black Sea,” says Stefano Lelli, a fishery expert for the eastern Mediterranean working for the General Fisheries Commission for the Mediterranean (GFCM). This regional fisheries management body, established by FAO, is leading efforts to promote sustainable fisheries and aquaculture in the Mediterranean and the Black Sea.

The damage that invasive species can cause to the environment and the economy are well known, but impacts on human health have been much less analysed. However, invasive species can cause impacts ranging from psychological effects, phobias, discomfort and nuisance to allergies, poisoning, bites, disease and even death.

IUCN has launched a global standard for classifying the severity and type of impacts caused by alien species, known as the Environmental Impact Classification for Alien Taxa (EICAT). This tool will alert scientists, conservation practitioners and policy makers to the potential consequences of invasive alien species, guiding the development of prevention and mitigation measures.

See also: Environmental Protection and Plant Health: A New IPPC Factsheet Explains the Link