Shrinking habitats threat to world?s ecosystems

Shrinking habitats threat to world?s ecosystems

NSF shrinking habitatWashington (ISJ) - World?s ecosystems are headed for disaster as habitats have been shrinking at an alarming rate. The fast depletion of habitats will not only have an adverse effect on ecosystems but on people and flora and fauna also.

An extensive study carried out by US National Science Foundation (NSF) reported that 70 percent of existing forest lands are within a half-mile of forest edges. It warns that encroachment of urban, suburban and agricultural land would lead to losses of plant and animal species.

The research, which tracked seven major experiments on five continents, found that fragmented habitats have reduced the diversity of plants and animals by 13 to 75 percent.

"The results are stark," said Doug Levey, program director in NSF's Division of Environmental Biology and a co-author of the paper. "No matter the place, habitat or species, habitat fragmentation has large effects, which grow worse over time."

Nick Haddad, a biologist at North Carolina State University and corresponding author of the paper, said the world?s forests were shrinking fast which was a disturbing trend.

"Nearly 20 percent of the world's remaining forests are the distance of a football field--or about 100 meters--away from forest edges. Seventy percent of forest lands are within a half-mile of forest edges. That means almost no forests can really be considered wilderness," Haddad said.

Fragmentation changes how ecosystems function, reduces the amounts of nutrients retained and the amount of carbon sequestered and has other deleterious effects.

"The initial effects were unsurprising," Haddad said. "But I was blown away by the fact that these negative effects became even more negative with time. Some results showed a 50 percent or higher decline in plant and animal species over an average of just 20 years.

"And the trajectory is still spiralling downward."

Haddad suggests conserving and maintaining larger areas of habitat; using landscape corridors, or connected fragments that are effective in maintaining higher biodiversity and better ecosystem function; increasing agricultural efficiency; and focusing on urban design efficiencies as some of the measures to mitigate the effects of fragmentation.

"Ultimately, habitat fragmentation has harmful effects that will also hurt people," said Haddad.

"This study is a wake-up call to how much we're affecting ecosystems--including areas we think we're conserving."

Source: USNSF

Image : An experimental forest in South Carolina)

Image courtesy: Nick Haddad|USNSF


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