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Credit: Farah Mukhida/Anguilla National Trust

Credit: Farah Mukhida/Anguilla National Trust

Saving Sombrero - Resurrection of a unique Caribbean wildlife haven

Case Study

The Caribbean is one of the world’s greatest centres of biodiversity, with over 10,000 species that occur nowhere else. In fact, the region ranks in the top three of the world’s 36 biodiversity hotspots in its astonishing wealth of unique, endemic species. But the region has also suffered among the highest extinction rates in modern history. Sombrero Island – a remote Caribbean island with species found nowhere else on earth – has been brought back from the brink of ecological collapse thanks to a groundbreaking conservation project spearheaded by Anguillan conservationists and a Caribbean alliance between Fauna & Flora and US conservation organisation Re:wild.

Sombrero bee. © Toby Ross / Fauna & Flora

Sombrero bee. © Toby Ross / Fauna & Flora

The Sombrero bee, one of the island's smaller endemic species.

Caribbean islands represent only 0.16% of the Earth’s land area but have accounted for 10% of the world’s bird extinctions, 38% of mammal extinctions and over 65% of reptile extinctions since the year 1600.

For the past three decades, Fauna & Flora and our partners in the Caribbean have been working to halt and reverse that depressing historical trend, often focusing on places and species that are largely unknown to the wider world.

Tiny Sombrero Island, 34 miles north-west of Anguilla, measures a mere 38 hectares. This miniature ecosystem harbours several threatened species that are unique to the island, including the Sombrero ground lizard, the Sombrero Island bee, and the Sombrero Island wind scorpion, a fearsome-looking – but harmless – spider-like invertebrate. It also supports globally significant seabird colonies and is designated as an Important Bird Area.

Caribbean islands cover 0.16% of the world's land area. But they account for:

The number of nesting seabirds on the island has soared since the restoration. © Edward Marshall / Fauna & Flora

The number of nesting seabirds on the island has soared since the restoration. © Edward Marshall / Fauna & Flora

10% of the world's bird extinctions

38% of mammal extinctions

Union Island gecko. Credit: Jeremy Holden / Fauna & Flora

Union Island gecko. Credit: Jeremy Holden / Fauna & Flora

65% of reptile extinctions

    The number of nesting seabirds on the island has soared since the restoration. © Edward Marshall / Fauna & Flora

    The number of nesting seabirds on the island has soared since the restoration. © Edward Marshall / Fauna & Flora

    10% of the world's bird extinctions

    38% of mammal extinctions

    Union Island gecko. Credit: Jeremy Holden / Fauna & Flora

    Union Island gecko. Credit: Jeremy Holden / Fauna & Flora

    65% of reptile extinctions

Sombrero ground lizard. © Toby Ross / Fauna & Flora

Sombrero ground lizard. © Toby Ross / Fauna & Flora

Hurricanes historically caused the number of critically endangered Sombrero ground lizards to decline significantly.

Tackling duel threats

Sombrero’s biodiversity faces two main threats: climate change, which has increased the frequency and intensity of hurricanes in the region, and invasive species, which upset the ecological balance of the island. Native species have evolved to cope with the storm surges and damage that hurricanes bring, but not with aggressive invaders that eat or outcompete them. By the time conservationists intervened in 2021, the populations of native plants and animals were already in a precarious state due to the presence of mice on the island. These invasive rodents prey on the native reptiles and insects, and even seabird eggs and chicks, as well as reducing vegetation cover by consuming the seeds and roots of plants.

Some of the native wildlife – their numbers already reduced by the invading mice – have already suffered major population shocks as a result of hurricanes. With numbers so low, the risk that the next big storm could wipe out entire species was high.

Sombrero Island wind scorpion. © Toby Ross / Fauna & Flora

Sombrero Island wind scorpion. © Toby Ross / Fauna & Flora

Increasingly extreme weather events pose an existential threat to native species such as the Sombrero Island wind scorpion.

Anguila High school students. © Farah Mukhida / Anguilla National Trust

Anguila High school students. © Farah Mukhida / Anguilla National Trust

High school students helping with a revegetation project to restore a greener landscape.

Locally driven recovery

The mission to protect Sombrero’s precious wildlife has met with great success. A concerted effort by Fauna & Flora’s local partner Anguilla National Trust to eradicate the invasive mice in 2021 led to the island being officially declared ‘mouse-free’ the following year. Removing the mice has allowed the native species to rebound – and given them the best possible chance of surviving the onslaught of climate change-driven storms.

Severe hurricanes in 1995 and 2018 had reduced the population of the critically endangered Sombrero ground lizard to fewer than 100 individuals. Those numbers have now increased eightfold, but facing the threat of more frequent storms, the species remains at risk of extinction.

Sombrero ground lizard numbers have increased eightfold.

With support from Fauna & Flora and Re:wild, Anguilla National Trust is also helping Sombrero’s natural vegetation to recover by planting native species to speed up regeneration. It is hoped that this process will restore the landscape to a greener, healthier ecosystem, protecting the island’s soils and its wildlife from storm surges, making it more resilient to the effects of climate change. The initial signs are encouraging, with native plants such as sea bean, spider lily and prickly pear already showing healthy new growth.

“The vegetation restoration is about establishing a more secure future,” said Anguillan conservationist Devon Carter, a research assistant with Anguilla National Trust. “The more diversity you have in terms of the vegetation, the more resilient it will be to a changing climate. Already, the island is looking greener and healthier. In the future we hope to see a whole different landscape and much more wildlife.”

Sombrero invasive species eradication team

    Aaron Richardson

    Jurvon Duncan

    Shamar Gaskin

    Gilbert Smart

    Maxrand Browne

    Marlene Horsford

    Jevon Morton

    Shaka Whyte

Caribbean-wide impact

The Sombero project is just one of the many successful offshore island restorations carried out by Fauna & Flora and Re:wild and their wide network of local partners, all of which have swiftly led to impressive improvements in vegetation cover and the recovery of numerous native species. The Caribbean alliance formed by the two organisations has made great strides in restoring island biodiversity by promoting and supporting ecosystem restoration throughout the region.

The Sombrero Island Restoration Project was made possible through financial support from King Charles III Charitable Fund, Betty Liebert Trust, Darwin Plus John Ellerman Foundation, US Fish & Wildlife Service’s Neotropical Migratory Birds Conservation and Fauna & Flora’s Species Fund.

Masked booby, Sombrero Island. © Toby Ross / Fauna & Flora

Masked booby, Sombrero Island. © Toby Ross / Fauna & Flora

A healthier ecosystem is crucial to the survival of Sombrero's wildlife.

Help us to replicate our Sombrero success across the Caribbean

The introduction of alien species to the Caribbean has pushed many of the region’s native species to the very brink of extinction. But there is still hope.

Please help Fauna & Flora restore even more threatened Caribbean islands to their former glory.

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