Turtles survived dinosaurs and have roamed the Earth for more than 200 million years. But today, these long-lived reptiles are among the most endangered animals on Earth, ahead of birds, mammals, fish or even amphibians. The destruction of their habitat, the overexploitation of these animals as pets, diseases and climate change are some of the reasons that have led them to this extreme situation throughout the world.
In a study published in Bioscience, a team of US scientists offers the first synthesis of the ecological consequences of the continuing decline and extinction of turtle species and shows the various roles each of them contributes to ecosystems, such as keeping food webs healthy, dispersing seeds, or creating necessary habitats for other species.
“Our purpose has been to inform the public of the many essential ecological roles that turtles play on a global scale and to raise awareness of the plight of these emblematic animals,” explains Whit Gibbons, emeritus professor of ecology at the University of Georgia, in the USA, and co-author of the study.
According to the scientists, turtles contribute to the health of many environments, including deserts, wetlands, freshwater habitats, and marine ecosystems.
“Their decline may have negative effects on other species, including humans, which may not be visible now,” says Jeffrey Lovich, a US Geological Survey scientist, and lead author.
Turtles have a significant impact on the ecosystem
Turtles can be herbivorous, omnivorous or even carnivorous, which is why they play essential roles in food chains. Their feeding habits influence the structure of other communities with which they share the habitat, especially if the populations are very numerous. The broad masses of turtles and their eggs are food for other animals.
On the other hand, some turtle species may be the central seed dispersing agents for specific plants, as the digestive tract destroys not all seeds.
Additionally, if turtles such as the Agassiz desert turtle in the southwestern US and the Gopher turtle in the southeastern US disappeared, certain spiders, snakes, amphibians, rabbits, foxes, or other reptiles would be ‘homeless.’ These species dig large burrows moving essential mounds of earth that are reused by other animals or plants.
“The ecological importance of turtles, especially freshwater turtles, is undervalued and generally understudied by ecologists,” says Josh Ennen, a researcher at the Tennessee Aquarium Conservation Institute. “The alarming rate of turtle disappearance could profoundly affect the functioning of ecosystems and the structure of biological communities around the world,” he added.