Following removal of invasive species, Puerto Rico’s Monito gecko population is thriving
- By : Thérèse Yarde
- Category : Biodiversity
- Tags: puerto rico

The Monito Gecko (Sphaerodactylus micropithecus) is found only on Monito Island, offshore off Puerto Rico. In 1982 the gecko was declared as endangered under U.S. federal law. Since then programmes to eradicate rats from the island have led to a rebound in gecko populations:
While hurricane-ravaged Puerto Rico continues to struggle with rebuilding efforts, a Puerto Rican gecko flourishes and is ready to be removed from federal protection, according to the U.S. Fish and Wildlife Service.
“This delisting is the latest recovery success achieved through partnerships with our state wildlife partners,” said Greg Sheehan, the U.S. Fish and Wildlife Service’s acting principal deputy director. “I want to recognize the great efforts of our colleagues at the Puerto Rico Department of Natural and Environmental Resources, other partners, and our employees, who together helped guide this species toward recovery.”
The Monito gecko is found only on Monito Island, a tiny 40-acre rock off Mona Island halfway between Puerto Rico and Hispaniola. Both Mona Island and Monito Island are protected by Puerto Rico as nature reserves.
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Monito Island’s tiny gecko was listed as endangered in 1982, eight short years after it was first “discovered.” The agency also designated the entire island as critical habitat for the little lizards. From 1940 to 1965, the island was used for target practice by the U.S. Air Corps/Air Force, and the effects of the gunnery range and bombing are still evident. Because the gecko was not discovered until nearly a decade after the bombing was discontinued, it is not known how that affected the population.
However, Fish and Wildlife noted that non-native black rats were abundant all over the island, and that rats eat lizards and their eggs. Several rat-eradication programs were enacted and the tiny island was deemed to be rat-free in 1999. The agency’s 5-Year Status Review conducted in 2016 found over 7,600 geckos, and the review team recommended the delisting.
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“The Monito gecko’s proposed delisting is a great example of how the Endangered Species Act (ESA) can leverage the attention and resources necessary to not just prevent extinction, but facilitate recovery” said Jaclyn Lopez, Florida director for the Center for Biological Diversity, a conservation group that frequently petitions and sues the agency on behalf of imperiled species. “If we don’t politically interfere with the ESA, let it do what Congress intended, species can and will recover, making the protection of the act no longer necessary.”
Read more in the full article from Courthouse News.
[Image credit: JP Zegarra, US Fish and Wildlife Service]