Gulf Coast Joint Venture (GCJV) scientists recently completed analyses demonstrating that the massive losses of coastal wetlands during the past half-century have reduced the capacity of Gulf Coast marshes to support wintering waterfowl. Potential impacts of the Deepwater Horizon oil spill to marsh vegetation and food production mean waterfowl may encounter even greater food shortages when they arrive on the Gulf Coast later this year.
“We’ve known for years that coastal habitat loss and degradation have been slowly reducing the Gulf Coast’s capacity to support wintering waterfowl,” said Dr. Mike Brasher, GCJV biological team leader. “However, no study had quantified the consequences of coastal marsh loss to waterfowl food availability.”
This study estimated the amount of habitat required to support winter waterfowl population objectives and compared that to the available habitat. “Basically, we asked how many acres of marsh it takes to feed a desired number of waterfowl, then compared that to what is presently on the landscape,” Dr. Brasher said.
The study area included coastal marshes from Mobile Bay, Ala., to Corpus Christi, Texas. Scientists used a measure called duck-energy-days (the dietary energy needed to sustain a single duck for a single day) to estimate how much food would be required to support population goals set forth by the North American Waterfowl Management Plan. Their calculations revealed that under the assumption of a 150-day winter period, coastal marshes in these areas satisfy energy demands of 2.9 million fewer ducks and geese than what they likely did during the 1970s. In southeast Louisiana alone, coastal marsh food resources may support 1.3 million fewer waterfowl than what is targeted by GCJV population objectives.
“Completion of this work represents a significant step in developing quantitative coastal marsh restoration objectives for waterfowl. But the sobering fact is that these results suggest Gulf Coast marshes may presently be unable to support historic populations of wintering waterfowl. As tragic and potentially harmful as the Deepwater Horizon oil spill is, I think the important thing to remember is that these marshes were under siege long before the spill, and there is every indication that those same forces will continue to threaten them long after the spill,” Dr. Brasher said. More:
http://www.prweb.com/releases/2010/06/prweb4119844.htm
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