The Monito Gecko: Saved by the Endangered Species Act

The US Fish and Wildlife Service, the Department of Natural and Environmental Resources of Puerto Rico, Island Conservation, and partners celebrate the federal delisting of the Monito Gecko.

The Monito Gecko, a small reptile, endemic to Monito Island, Puerto Rico, has officially been delisted under the Endangered Species Act (ESA), joining the ranks of the Bald Eagle and the Brown Pelican.

Since 1982, the Monito Gecko has been protected under the Endangered Species Act (ESA), threatened with extinction largely due to predation by invasive rats. To protect Monito Island’s unique fauna including the Monito Gecko, the Department of Natural and Environmental Resources of Puerto Rico (PR-DNER) worked to remove invasive rats from the island. In 2014, PR-DNER and the USFWS officially declared Monito Island free of invasive rats—eliminating the geckos’ greatest threat to survival.

A Monito Gecko peeking out from cover. Credit: JP Zegarra, USFWS

In 2016, Island Conservation joined the USFWS and PR-DNER on a monitoring trip to Monito Island to determine the population of the Monito Gecko. Today, there are an estimated 7,600 geckos on the Island—a population stable enough to warrant delisting, making the Monito Gecko the first Caribbean endemic species to be delisted under the Endangered Species Act.

Since the creation of the Endangered Species Act in 1973, it has successfully prevented the extinction of at least 99% of species listed as of 2013, but very few species have been removed from the list because of recovery. The Monito Gecko is now one of these few species along with Bald Eagles and other iconic wildlife that has been protected and ultimately removed from the ESA list due to conservation and habitat protection.

This action is the most recent recovery success of a species thanks to the collaboration of conservation agencies and organizations, and demonstrates how well the ESA works in wildlife protection.”

Bryan Arroyo, Deputy Director of the USFWS

An adult Monito Gecko is only about an inch and a half long and would fit on your index finger and still have spare space. Its name comes from Monito Island which it is endemic to, a karso rock covered in dry, forest, shrub vegetation.

Monito Island as a nature reserve, designed to protect native wildlife and vegetation. In addition, to the Monito Gecko, the Island is home to one of the largest seabird colonies in the Caribbean. Along with this, two other unique, endangered species: the Lady Bird of Puerto Rico and the prickly cactus pear.

The USFWS, DRNA and other groups will continue to monitor the gecko population to ensure long-term viability and maintain biosecurity protocols to prevent the reinvasion of rats.

Endangered Species Act

  • The Endangered Species Act was signed into law in 1973
  • It is intended to provide a framework for how to protect threatened and endangered wildlife in the United States and US territories.
  • Species can be delisted for three reasons:
    • The species has recovered to the point that it no longer needs the ESA’s protection.
    • The original information warranting listing has been shown to be incorrect, or new information suggests that the species is not actually endangered or threatened.
    • The species has become extinct.
  • While the ESA has staved off extinction for many species, relatively few species have been delisted due to recovery.
  • Learn more at USFWS, NOAA, and NWF.
  • Learn more about the delisting of the Monito Gecko

Why Islands

Islands represent both a unique conservation need and opportunity. Islands total only a small fraction of our planet’s land area and host a disproportionately higher rate of extinction and endangerment per unit area than continents. For this reason, investing limited conservation funds on islands provides a high return on investment.

  • There are ~465,000 islands in the world, yet they comprise just 5.3% of the Earth’s terrestrial area.
  • Islands have been epicenters for extinctions: Islands have hosted 75% of known bird, mammal, amphibian and reptile extinctions since 1500.
  • Islands provide critical refuges for highly-threatened species, currently supporting 36% of bird, mammal, amphibian and reptile species that are classified as Critically Endangered on the IUCN Red List.
Islands are extinction epicenters

Invasive alien species are a major driver of species extinctions on islands, particularly invasive mammals.

  • Many islands’ species are threatened as a direct consequence of invasive alien species, particularly invasive mammals. Invasive cats and rats are the most damaging invasive species known on islands.
  • Invasive species devour eggs, young and even adults of native animals and plants, spread invasive seeds, and destroy vegetation.

Islands offer hope that we can prevent extinctions and protect biodiversity.

  • Eradication of invasive mammals from islands is a proven conservation tool.
  • More than 1,200 invasive mammal eradications have been attempted on islands worldwide, with an average success rate of 85%.
  • Larger more remote and technically challenging islands are being successfully cleared of invasive species populations each year.
  • Many of these investments have resulted in remarkable stories of restoration success, including the recovery of globally threatened species.

Featured photo: Monito Island. Credit: USFWS

About Island Conservation

Island Conservation prevents extinctions by removing invasive species from islands. To date, we have successfully restored 64 islands worldwide, benefiting 1195 populations of 487 species and subspecies. Working together with local communities, government management agencies, and conservation organizations, we select islands that have the greatest potential for preventing the extinction of globally threatened species.

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