Restoring Habitat for The Iguanas of Mona Island

Island Conservation Restoration Specialist Cielo Figuerola explains how invasive Australian Pines on Mona Island harm native iguanas and shares how Island Conservation plans to restore the Endangered species’ critical nesting areas.

By: Cielo Figuerola

I’m headed to Mona Island to begin implementation of a project focused on restoring nesting sites for the Endangered and endemic Mona Island Rock Iguana by removing the invasive Australian Pine. This project was developed by the US Fish and Wildlife Service through the Coastal Program, the Department of Natural and Environmental Resources of Puerto Rico (DNER), and Island Conservation, with the support of the local NGO Vida Marina.


Endemic Mona Island Rock Iguana. Credit: Tommy Hall/Island Conservation

Australian pines were introduced to Mona in the 1930s so their wood could be harvested and used for various purposes, as for example, utility poles. However, transporting the wood off the island was very expensive and logistically challenging. As the years went by, profits decreased and markets changed, and the pine plantation was abandoned. Unfortunately, the plantation was established on prime nesting habitat for the Mona Iguana, making nesting very hazardous.

Invasive Australian pines have harmful impacts on Mona’s ecosystem in many ways. Through the release of certain compounds they change the chemistry of the soil, preventing growth of native vegetation, they can cause beach erosion in coastal habitats, and they can decrease plant biodiversity, just to name a few. For iguanas specifically, when pine needles fall and cover the ground and form an almost uniform carpet of invasive plant matter in the understory, the sandy substrate iguanas need to excavate to build their nests disappears. The pine needle carpet prevents them from nesting in these areas. Another problem is the constant shade produced by the pines–iguanas need to build their nests in areas with sun exposure because their eggs need heat to develop. In the shady pine forest this is not possible.

Invasive Australian pines have harmful impacts on Mona’s ecosystem in many ways.

These pine impacts combined with the ongoing invasive vertebrate species impacts (like egg and hatchling predation by feral pigs and cats) put Mona Iguanas at risk, especially during their most vulnerable life stages.


Removing invasive Australian Pines on Mona Island. Credit: Cielo Figuerola/Island Conservation

Our main goal with this project is to cut down the pines, remove the pine needle carpet, and then place trail cameras in the restored sites to document iguanas using these newly habitable areas to nest this upcoming nesting season starting in July. We’re hoping that the wood from these trees can be repurposed to repair infrastructure on island. Vida Marina has vast expertise in Australian Pine felling since this is what they do through their coastal restoration efforts in the northern region of Puerto Rico.

We are all very excited for this trip and the possibility to start restoring a habitat through the removal of an invasive plant!

Featured photo: Aerial shot of Mona Island, Puerto Rico. Credit: Tommy Hall/Island Conservation
Versión en Español/Spanish transcript

About Cielo Figuerola

Cielo is currently finishing her doctoral studies in Ecology and Evolution at the University of Puerto Rico. She has worked with Island Conservation since 2012 to protect endangered species, especially on Mona Island where she works to protect the Mona Island Rock Iguana. Traveling, exploring the outdoors, and discovering the simple but amazing details of the natural world are among the things she enjoys the most.

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