People, Environment

Deforestation Threatens Countless Tropical Species

Deforestation may be the driver of the sixth mass extinction.Deforestation may be the driver of the sixth mass extinction.

Scientists have long believed that the rate at which humans are destroying tropical forests and the habitat those forests represent could drive a global mass extinction event, but the extent of the potential losses has never been fully understood.

New research published in the Proceedings of the National Academy of Sciences provides further evidence that, even if the world has not already entered a sixth era of mass species loss on a global scale, it may yet be imminent, Mongabay reported.

John Alroy, a professor of biological sciences at Australia’s Macquarie University, examined local-scale ecological data to forecast potential global extinction rates and found that hundreds of thousands of species are at risk if humans disturb all pristine forests remaining in the tropics.

“Disturbance is no small matter, because roughly two-thirds to three-quarters of the entire world’s species are found in tropical forests even though tropical forests only cover about 10% of the entire Earth’s continental area,” Alroy said in a statement.

“Mass extinction will occur primarily in tropical forests because Earth’s terrestrial biodiversity is so heavily concentrated in those ecosystems.”

In order to examine just how severe the impacts might be, he applied a highly accurate method of estimating species richness to data from 875 ecological samples of trees and 10 other groups of organisms “of keen ecological interest”, including bats, insects (ants, butterflies, mosquitoes, and scarabs), large and small mammals, and other vertebrates (birds, frogs, and lizards).

The samples were collected in a variety of habitat types in tropical zones that were originally forested from primary and fragmented forests to plantations and pasturelands.

Alroy projects that if Earth’s remaining tropical forests are completely disturbed, more than 18% of species will be lost in every group studied, except large mammals and mosquitoes. Seven of the groups he examined will lose greater than 28% of species.

Trees, for instance, stand to lose as much as 30% of species, while ants could lose as much as 65%.

There is reason to hope that humans can still prevent such large-scale loss of life. Previous research has shown that protecting 50% of the planet’s land area is a sort of baseline for ensuring the health of ecosystems and, in turn, the survival of life on Earth.

This concept, often referred to as “Nature Needs Half,” is widely regarded as not just valid but feasible by conservationists.


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