The risk is particularly high for herbivorous reptiles, such as turtles, and large herbivores, such as elephants.
August 7, 2020 22h29
The herbivores are most at risk of extinction as predators
WASHINGTON — The herbivorous animals are at a greater risk of extinction than predators and omnivores, according to a study published Wednesday in the journal Science Advances. And this, whether they be mammals, birds or reptiles.
The risk is particularly high for herbivorous reptiles, such as turtles, and large herbivores, such as elephants. But the trend is true regardless of the habitat (desert, forest…) and class (mammals, birds, reptiles), according to this analysis most of 24,500 species living and extinct.
The authors of the study from several universities, including that of Utah and Imperial College London, write that the predators are often perceived as more vulnerable, because of their extensive territories, and the low rate of growth of their populations, and because many studies were interested in predator-specific and charismatic, actually in danger.
In reality, “we have established that the trophic level and size were important factors in the risk of extinction”, the researchers say. The trophic level is the level of animals in the food chain: predators are at the top.
“There is so much published data that sometimes all it takes is someone to organize them,” said Trisha Atwood, first author of the study, to Science.
Data compiled by the group are interested in both the past (dating back to the end of the Pleistocene there are 11,000 years old), the recent (500 years) and in the present, with similar conclusions. About a quarter of the herbivore species studied here are today threatened with extinction, according to the classification of reference of the international Union for the protection of nature (IUCN). 100% of herbivorous reptiles of the marine environments are threatened.
The herbivores are also over-represented among extinct species.
Exceptions appear to be: fish-eating species and scavengers also had a level of relatively high risk. And the predators of the oceans are, in reality, very threatened.
Why the herbivores would they be more at risk, in fine? The researchers cite a hypothesis: invasive species, such as rats, insects, or plants, disproportionately affect herbivorous reptiles, compared to omnivores and predators.