Over half of all crocodilians, a group that includes crocodiles, alligators, caimans, and gharials, are threatened with extinction. But they take up important roles in our world. Not only do some species create shelter for other animals through unique burrow systems they dig out, others are also known to crunch down on invasive, agricultural pests. A new study, led by ZSL (Zoological Society of London), outlines some of these vital services that stand to be lost if the world’s crocodiles and alligators are not better protected. The researchers in this first-of-its-kind study argue that up to 38% of the diverse ecological functions that crocodilian species provide for wider ecosystems are at risk of being lost.

Published today (Friday 5 August) in Functional Ecology, the new study identifies the species of crocodile, alligator, caiman and gharial most in need of conservation action. They each play important, but different and diverse roles in the ecosystems in which they live, leading authors to call for greater conservation protections for these highly threatened species, based on their unique ecologies.

The study investigates the diversity of crocodilian ecological roles by looking at measurable characteristics linked to how species function in their environment, such as skull shape, body size and habitat use. The researchers developed a database of these key characteristics for all species, revealing often surprising ecological functions performed by the crocodilians.