Invasives Blog

Invasive alien species (IAS) explored in a CABI-published book pose the biggest threat to biodiversity, crop and/or livestock production, human and/or animal health, and economic development in the Caribbean.

These include rats, cats, mongoose and monkeys as part of a list of 171 exotic, non-native, non-indigenous or foreign animal species detailed in the 402-page ‘Guide to the Alien and Invasive Animals of the Caribbean,’ by Dr Arne Witt, CABI’s Invasives Coordinator, South.

Invasive alien species have been implicated in 86% of island species extinctions since 1500 A.D. Alien species are the most common threat associated with extinctions in native amphibian, reptile, and mammal species. In fact, introduced rats and cats have been responsible for most bird and mammal extinctions on islands.

Introduced species have not only driven native species to extinction, but they have also had a significant impact on food production. At a global level pests, many of which have been introduced, reduce yields by between 20 and 40%. Invasive insects cost the global economy about US$ 70 billion per annum. Many of the worst crop pests in the world are established and thriving in the Caribbean.

Invasive species can also affect human health in several different ways, either as introduced pathogens or as vectors of diseases and parasites. In fact, the global health costs directly attributable to invasive insects exceed US$ 6.9 billion per year.

These impacts are not new. It is postulated that an invasive species, that is the introduced black rat, contributed to the demise of around 200 million people in Europe between 1347 and 1351. The black rat is a host of fleas which can carry the bacterium Yersinia pestis which causes bubonic plague.

171 exotic, non-native, non-indigenous or foreign animal species

The guide, which is co-authored by Professor Mike Picker, of the University of Cape Town, South Africa, and Dr Kirsty Swinnerton, from the Kent Wildlife Trust, UK, provides detailed descriptions and information on the impacts of invasive taxa from mammals to insects. It also provides a review of the advantages and disadvantages of different management interventions.

Species covered include  thehouse sparrow (Passer domesticus), red-eared slider (Trachemys elegans), cane toad (Rhinella marina), red lionfish (Pterois volitans), Savigny’s brittle star (Ophiactis savignyi), pink hibiscus mealybug (Maconellicoccus hirsutus) and the Atlanic blue crab (Callinectes sapidus).

Prevention, early detection and rapid response (EDDR) and control

Dr Witt, Professor Picker and Dr Swinnerton outline in the guide that to be effective, all invasive alien management strategies need to consider activities relating to prevention, early detection and rapid response (EDDR) and control.

In the introduction they highlight the benefits of various interventions. Islands from which introduced mammals have been eradicated have seen a dramatic increase in the diversity and abundance of plants, insects, mammals and especially birds. The guide highlights the fact that invasive vertebrate eradication on islands has probably contributed more to biodiversity conservation globally than any other intervention.

Dr Witt said, “This guide has been developed to help address one of the barriers to effective IAS management, which is the lack of information on the presence, impact, and management of invasive animal species in the Caribbean. It is by no means a comprehensive guide, and does not necessarily cover all of the worest species but is an attempt to highlight the range of alien species present in the region and their impacts.”

One of the world’s greatest centres of biodiversity

The Caribbean region is one of the world’s greatest centres of biodiversity; home to a myriad of species that are found nowhere else on earth. It includes about 11,000 species of plants, of which 72% are endemic or unique to this hotspot.

Endemic vertebrates include all of the 189 species of amphibians present in the Caribbean; 95% of the 520 reptile species; 26% of the 564 bird species; and 74% of the 69 species of mammals, mostly bats. Species endemic to this hotspot represent 2.6% of the world’s plant species and 3.5% of the world’s vertebrate species. 

The publication is an output from the  Global Environment Facility (GEF) funded project, “Preventing the COSTS of Invasive Alien Species (IAS) in Barbados and the OECS” which is implemented by the United Nations Environment Programme (UNEP) and executed by CABI, in partnership with the Governments of Antigua and Barbuda, Barbados, Grenada, Dominica, St. Kitts and Nevis, St. Lucia and St. Vincent and the Grenadines

It aims to bridge a knowledge gap regarding the presence, distribution, impacts and possible management interventions for most invasive alien plant species in the Caribbean.

Additional information

Main image: The black rat (Rattus, rattus) is a major pest of the islands of the Caribbean as a carrier of disease including the bacterium Yersinia pestis which causes bubonic plague (Credit: Pixabay).

Book reference

Witt, A., Picker, M., Swinnerton, K, (2024) Guide to the Alien and Invasive Animals of the Caribbean. CABI, Wallingford, UK, vi + 402 pp. DOI: 10.1079/9781800627598.0000

Find out more and access the book from the CABI Digital Library here.

About the authors

Arne Witt is currently the Regional (Africa and Asia) Coordinator for Invasive species for CABI, based in Wilderness (George), South Africa. He has been an International Project Coordinator and/or Technical Advisor for a number of regional and national UNEP-GEF IAS Projects in Africa, Asia, Caribbean, and the Middle East. In these roles he has worked with countries in developing policies, building capacity, creating awareness, and developing and implementing best management practices, including biological control. He continues to develop and implement IAS projects in these regions. Arne has a PhD from the University of the Witwatersrand, South Africa. He has Master of Science degrees in Entomology (Stellenbosch University) and Conservation Biology (University of Cape Town). He has published a number of journal articles, and authored or co-authored book chapters and books on the identification and management of invasive alien species.

Mike Picker is an Emeritus Professor in the Biology Department of the University of Cape Town. He has published over 130 papers on insect ecology, diversity, and systematics, working largely in the semi-arid parts of Southern Africa. He has written five illustrated field guides for the Southern African region, including guides to Freshwater life, Alien and invasive animals, insects and most recently the moth fauna.

Kirsty Swinnerton works primarily on the recovery of endangered species, mostly in island ecosystems. She is a strong proponent of using hands-on management techniques to restore threatened species, including invasive alien species eradication and control. Early on in her career she experienced first-hand the devastating impacts of invasive species through her work to restore the Mauritius Pink Pigeon. Subsequent work in Hawaii, Pacific Northwest, and the Caribbean consolidated her focus on invasive species, particularly towards eradication to restore seabird populations and endemic reptiles. She is co-Chair of the invasive species working group for BirdsCaribbean, a network of more than 60 partners across the region committed to conserving Caribbean birds and their habitats.

CABI’s work on invasive alien species in the Caribbean

In July 2023, Dr Daniel Elger, CABI’s CEO, and Dr Qiaoqiao Zhang, Memberships Director, have completed a two-week visit to the Caribbean, taking in three of CABI’s 48 Member Countries, Guyana, Jamaica and Trinidad and Tobago, to strengthen strategic partnerships with stakeholders in the region.

Accompanied by Mr Naitram (Bob) Ramnanan, CABI’s Regional Representative for the Caribbean, they met with a number of organizations to discuss work in partnership to safeguard food security and biodiversity in these three countries and the wider Caribbean region.

The CABI delegation had productive dialogue with Ministries of Agriculture (MoAs) and other key stakeholders including, the Caribbean Agriculture Health and Food Safety Agency (CAHFSA) of the Caribbean Community (CARICOM), the Caribbean Agricultural Research & Development Institute (CARDI) and the Caribbean Biodiversity Fund.

CABI Member Countries and other institutions were canvassed for support to create a Caribbean Invasive Alien Species Trust Fund (CIASTF).

It is hoped that the CIASTF will independently mobilize, blend, and oversee the collection and allocation of financial resources and build the capacity needed to facilitate a strategic focus on Invasive Alien Species (IAS) management in the region, providing long-term funding for a longer-term problem. Read more in the news story ‘CABI visit to Caribbean strengthens strategic partnerships to help safeguard food security and biodiversity.’