By Renoir J. Auguste, 8th May 2025
Amphibians are found on all continents except for Antarctica; from Southeast Asian wetlands to South American jungles, and from temperate mountain tops to remote tropical oceanic islands. They are an especially important group of animals to study because they are the most imperilled vertebrate class, more threatened with extinction than birds or mammals. And because of the role they play in controlling pests, as well as in medical research (they are a source of compounds that can be used to treat human diseases), they are hugely important to both people and the environment.
Tobago glass frog, Hyalinobatrachium orientale tobagoense, a subspecies endemic to the island of Tobago. Photos: Renoir J. Auguste.
Although amphibians are distributed globally, species richness is greatest in the tropics where anthropogenic threats such as climate and land-use changes can have severe impacts. In our study, we examined nearly 800 research papers looking at the vulnerability of amphibians to these two major global threats.
We were particularly concerned with amphibians on tropical oceanic islands, which are home to many endemic species, have historically been of less interest to researchers and face additional challenges such as natural disasters and limited financial resources.
Caribbean sea view from the island of Tobago. Photo: Renoir J. Auguste.
Worryingly, we found only 18 of the amphibian-focused studies we reviewed (2%) had been carried out in tropical oceanic islands over the 2 decades between 1998 and 2022, fewer than for any of the other regions we considered. In fact, North America boasts five times as many studies on amphibians than oceanic tropical islands do.
Gathering more information on island amphibians is particularly important as current limitations to their conservation on oceanic islands include a lack of knowledge of adaptation in these specific habitats, few local researchers, limited ecological data on the effects of global threats on amphibian survivorship, and weak or limited policies specifically focusing on amphibians
Our results also revealed that, even for the few studies that were carried out on tropical islands, nearly 80% of the authors were not based on the islands in question, with most being affiliated with institutions in North America.
Charlotteville litter frog Prsitimantis charlottevillensis, a species found only on the island of Tobago. Photo: Renoir J. Auguste.
Together, these findings led us to outline some urgent recommendations towards narrowing this data gap and building local capacity for research on tropical islands.
We want more training opportunities and resources to be made available to island-based researchers, and we advocate for meaningful collaborations between international and island-based scientists and practitioners, replacing the ‘parachute science’ model that has historically dominated in the tropics.
A montane tropical forest, a habitat for frog species on the island of Tobago. Photo: Renoir J. Auguste.
Building capacity through training and involving local scientists in research on amphibians and their response to threats will be vital to understanding and protecting these diverse yet vulnerable species.
I hope our work raises awareness of this concerning gap in knowledge and encourages much needed research into the effects of global threats on amphibians, especially in the tropics and on oceanic islands.
Tobago glass frog, Hyalinobatrachium orientale tobagoense, a subspecies endemic to the island of Tobago. Photos: Renoir J. Auguste.
In the meantime, existing management plans should be adapted and adopted by island nations to give amphibians the best chance of survival in the face of persistent threats, including climate change and land-use change.
As a Caribbean native, I am passionate about raising awareness of amphibians, their diversity and conservation, and I hope that more interest and resources will be made available so that we can help to protect this important group of animals in our home lands for generations to come.
The article ‘Are tropical oceanic islands overlooked? Knowledge gaps regarding the vulnerability of amphibians to global anthropogenic threats’ is available open access in Oryx—The International Journal of Conservation.
