Timely action may save rare species from extinction: study

Washington: Timely action may be able to save threatened species, according to a new study which found that patterns of species loss following habitat disruption are similar in birds, mammals, plants, reptiles and invertebrates.

Loss of plant and animal habitat leads to local species extinctions and a loss of diversity from ecosystems, researchers said. However, not all of the extinctions occur at once. Conservation actions may still be able to save threatened species, according to William Newmark from University of Utah in the US.

Researchers compiled data from biodiversity and extinction reports, finding that patterns of species loss following habitat disruption are similar among birds, mammals, plants, reptiles and invertebrates. They also found that while species loss commences quickly, timely action could slow extinction rates and save
species. When natural habitats are lost, species lose the physical space and resources they need to continue growing and expanding.

Habitats are usually lost due to human activity, such as building roads or clear-cutting a forest. After such a disturbance, the habitat can no longer support the number of species that live there and species begin to disappear until the habitat reaches a new normal, researchers said. The difference between the old and new amounts of biodiversity the habitat can support is called the "extinction
debt," they said.

Researchers, including those from University of Ioannina and University of Thessaloniki in Greece reviewed 43 studies from 1971 to present that included descriptions of biodiversity loss following habitat fragmentation in five taxonomic groups - mammals, plants, birds, reptiles and invertebrates. They found a shallow J-shaped curve, nearly identical in each taxonomic group, that described how the rates of extinction loss change over time.

At first, extinction rates are high, and then decelerate until the point at which half of the extinction debt is paid off. After that point, species loss continues but at a slower rate until a new equilibrium is reached. Several factors influence the timeline in which the biodiversity loss process plays out, but Newmark said that all groups they studied, even those thought to be resistant to extinction such as plants, showed the same pattern.

These similar patterns emerge if species loss is calculated in terms of average population size and time for a new generation to arise for these taxonomic groups. "This study has important implications for conservation, whether it is in national parks, tropical forest remnants, or oceanic islands," said Newmark.
"It emphasises the importance of acting quickly," he said. The findings were published in the journal Nature Communications.