Most polluted ecosystems can recover

May 28th, 2009 - 1:06 pm ICT by IANS  

Washington, May 28 (IANS) There’s some cheerful news for conservationists. Most polluted or damaged ecosystems can recover within a lifetime if societies commit to their clean-up or restoration, according to an analysis of 240 independent studies.
Conducted by researchers from the Yale School of Forestry & Environmental Studies (YSFES), the study found that forest ecosystems recovered in 42 years on average, while ocean bottoms recovered in less than 10 years.

When examined by disturbance type, ecosystems undergoing multiple, interacting disturbances recovered in 56 years, and those affected by either invasive species, mining, oil spills or trawling recovered in as little as five years.

Most ecosystems took longer to recover from human-induced disturbances than from natural events, such as hurricanes.

“The damages to these ecosystems are pretty serious,” said Oswald Schmitz, ecology professor at the YSFES and co-author of the meta-analysis with doctoral student Holly Jones.

“But the message is that if societies choose to become sustainable, ecosystems will recover. It isn’t hopeless,” he said.

The Yale analysis focusses on seven ecosystem types, including marine, forest, terrestrial, freshwater and brackish, and addresses recovery from major disturbances, such as agriculture, deforestation, invasive species, logging, mining, oil spills, overfishing, power plants and trawling and from the interactions of those disturbances.

Researchers analysed data derived from peer-reviewed studies conducted over the past century that examined the recovery of large ecosystems following the cessation of a disturbance.

The studies measured 94 variables that were grouped into three categories: ecosystem function, animal community and plant community.

The Yale analysis found that 83 studies demonstrated recovery for all variables; 90 reported a mixture of recovered and non-recovered variables; and 67 reported no recovery for any variable, said an YSFES release.

Aquatic systems, the researchers noted, may recover more quickly because species and organisms that inhabit them turn over more rapidly than, for example, forests whose habitats take longer to regenerate after logging or clear-cutting.

Their findings will appear in the June edition of PLoS ONE.

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