Remote islands are home to a remarkable diversity of reptile species, many of which are unique to these isolated habitats. However, new scientific findings indicate that these reptiles are facing a significantly heightened risk of extinction, with as many as 30 percent of island-dwelling reptile species now considered endangered.

A research team led by the University of Oxford, in collaboration with international partners, has published a comprehensive analysis in the journal Conservation Science and Practice. The study highlights that, although islands make up less than seven percent of the Earth's surface, they harbor a disproportionately large share of global reptile biodiversity. Approximately one-third of the world's 12,000 documented reptile species inhabit islands, including iconic animals such as the Galápagos giant tortoise and the Komodo dragon.

Island reptiles possess distinctive physiological and behavioral adaptations, such as impermeable skin and the ability to survive extended periods without food or water. These traits have enabled them to thrive in insular environments. However, the research points out that their isolation also renders them extremely vulnerable to environmental threats, making their populations particularly susceptible to decline.

Significant Threats to Island Reptiles

The analysis reveals that about 30 percent of reptile species living on islands face extinction, more than double the global average risk for reptiles, which stands at 12 percent. The primary factors driving this crisis include agricultural expansion, deforestation, pollution, and the introduction of non-native species. For instance, invasive predators like feral cats pose severe challenges for native reptiles. Many island reptile species evolved without mammalian predators and, as a result, lack effective defense mechanisms. This makes them especially vulnerable to predation by introduced species, which have already contributed to dramatic population declines in various regions.

Reptiles such as snakes, tortoises, and geckos play crucial roles in maintaining the ecological balance of island ecosystems. On the island of Madeira, for example, wall lizards help regulate insect populations, pollinate plants, and disperse seeds. Scientific observations have shown that a single feral cat on an island can consume more than 90 lizards in a year, illustrating the potential impact of invasive predators on fragile island environments.

Understudied Species at Greater Risk

The study also found a significant research gap regarding island reptiles. Only about seven percent of scientific literature on reptiles published since 1960 has focused on those living on islands, especially endangered species. Larger or more widely distributed species tend to attract more scientific attention, leaving smaller, lesser-known island reptiles understudied and underprotected.

One notable example is the Príncipe emerald snake (Hapsidophrys principis), which is native solely to the small island of Príncipe in the Gulf of Guinea. Despite its critical role as a predator in its local ecosystem, there is very little research on its population trends or ecological requirements. This lack of data hinders effective conservation strategies and increases the risk of extinction for such endemic species.

Recommendations for Conservation

To address these challenges, the researchers advocate for increased targeted studies on island reptile species, especially those at highest risk. They recommend fostering collaborations between national research institutions and island communities, as well as integrating traditional and local knowledge into scientific efforts. Enhanced research and conservation action are considered essential to prevent further biodiversity loss and to preserve the ecological integrity of island habitats.

This comprehensive study underscores the urgent need for global attention and coordinated conservation measures to safeguard the future of island reptiles, many of which may disappear before their ecological roles are fully understood.