Turtles might seem like the world's steadiest creatures, but their population is in serious decline — and that's bad news for the planet.

New research paints a dire picture of turtles as 61 percent of the 356 species of turtles are already threatened or extinct.

In a new study published in the journal BioScience, a team of scientists from various institutions reveals that turtles are one of the most threatened among the major vertebrate groups. This could, the authors say, have serious consequences on the ecological landscape.

"Turtles contribute to the health of many environments, including desert, wetland, freshwater and marine ecosystems, and declines may lead to negative effects on other species, including humans, that may not be immediately apparent," Jeffrey Lovich, lead author and U.S. Geological Survey scientist, explains in a press release from the University of Georgia.

The Disappearance Of The World's Turtles

As far back as the age of dinosaurs millions of years ago, turtles have roamed the Earth. However, the destruction of their habitats, disease, climate change, and over-exploitation for pets and food have caused their population to drop dramatically.

Whit Gibbons, senior author and professor emeritus at University of Georgia's Savannah River Ecology Laboratory and Odum School of Ecology, says in a statement that the purpose of the study is to inform people about the numerous, critical ecological roles of turtles.

Turtles Are Crucial To The Food Chain

One of the important qualities of turtles is how diverse they are when it comes to food. Turtles can be herbivores, omnivores, or carnivores, and range from specialists who feed on just a handful of food sources or generalists who have a wider spectrum of choices. This diversity allows them to have a major impact in food webs of their habitats all over the world.

In some areas, the sheer density of the turtle population make them an integral part of the ecosystem. With their number, other species that feed on them and their eggs are assured a large pool of potential food.

Turtles Disperse Plant Seeds

For plants, turtles are also extremely important as they distribute the seeds of many plant species. When they eat, some seeds are not destroyed by the digestive process and instead make its way out of the animal's body in convenient dispersal. Certain seeds even germinate better after going through this process.

Some turtles are the main dispersal agents of certain plants and their seeds, so their disappearance can hasten the extinction of these flora as well.

Turtles Create Homes For Other Animals

Turtles may carry a convenient shelter on their back, but they apparently make habitats for other creatures.

The Agassiz's desert tortoise and the gopher tortoise are both known to dig burrows that are used as habitats by other species including bobcats, foxes, rabbits, snakes, spiders, insects, amphibians, and other reptiles. Some plant species also sprout from the burrow entrances.

These are only a few yet very crucial roles that turtles play in the ecological landscape. Unfortunately, many species are in serious decline and in danger of disappearing completely.

"Our hope is that everyone will be encouraged to engage in concerted efforts to conserve their well-earned legacy as part of our natural habitats," Gibbons says.