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Two new scientific reports put real numbers behind history of oyster reefs; economics of restoration

Two studies released today by scientists at The Nature Conservancy shed new light on the history of oyster reefs in the United States and demonstrate that restoring these reefs makes good economic sense.


ARLINGTON, Virginia | June 13, 2012

Two studies released today by scientists at The Nature Conservancy shed new light on the history of oyster reefs in the United States and demonstrate that restoring these reefs makes good economic sense.

In an effort to advance the field of coastal restoration, The Nature Conservancy and a team of scientists from more than a dozen management agencies and research institutions conducted an in-depth study of oyster reef habitat and, for the first time, the actual biomass (the “living weight”) of oyster reefs in dozens of estuaries throughout the United States.

Historical ecology with real numbers: past and present extent and biomass of an imperiled estuarine habitat, published today in Proceedings of the Royal Society B, presents the first truly quantitative estimates of decline in oyster habitat for the United States. The report looks at existing oyster reefs in nearly 40 bays and estuaries throughout the United States and compares them to those numbers with records from 110 years ago.

The findings show that while that reef area declined by 64 percent, reef density had dropped by 88 percent, revealing that simple physical area is an unreliable indicator of habitat status.

“We’ve lost most of the living weight of our oyster reefs. Even if the remnant of one is still there, it’s not providing benefits – like water filtration and fisheries enhancement – the way it could be,” said Dr. Rob Brumbaugh, Restoration Program Director for The Nature Conservancy and co-author of the report. “It’s like clear-cutting a forest, but still calling it a ‘forest’ because the stumps are still there, even though they aren’t making oxygen or storing carbon.”

The findings provide a powerful baseline – a clear vision of how things were and how they are now – and helps to measure progress and to establish meaningful restoration goals.

“Oysters are and have been a valuable resource, even a century ago, so government surveyors mapped vast acreages and built up a story of a critically important habitat in wonderful detail,” said lead author Dr. Philine zu Ermgassen, University of Cambridge. “Using those meticulous records, we have been able to quantify the changes in reefs in more detail than anyone has ever done before. Managers and scientists need to pay closer attention to density when setting restoration or conservation objectives.”

In addition to aiding restoration, the study will inspire it, says co-author Dr. Mark Spalding, a lead scientist with The Nature Conservancy’s Global Marine Program.

This is a call to action for conservation of reefs as well as other habitats. Almost all of our concerns about the loss of natural areas – from forests and wetlands to seagrass meadows and kelp beds – are based on an estimation of change in area,” said Dr. Spalding. “This study shows that the losses may be even worse than we thought, because the quality of the remaining patches of habitat may be so diminished that it is not providing the function we expect from any given area.”

In the second report, environmental economist Timm Kroeger, Ph.D., with The Nature Conservancy looked specifically at oyster reef restoration in the Gulf of Mexico. The Gulf projects he examined could serve as examples for the rest of the nation.

Kroeger completed the most comprehensive study to date that measures the economic and social benefits that reef restoration provides to Gulf Coast communities. The study, Dollars and Sense: Economic Benefits and Impacts from Two Oyster Reef Restoration Projects in the Northern Gulf of Mexico, is based on analysis of two planned restoration projects in Alabama and draws on findings from studies of restored and natural reefs in Mobile Bay and other parts of the Gulf.

“We found that an investment in oyster reef restoration will have a several-fold return on investment in terms of recreational and commercial fisheries and protection of property and public infrastructure,” said Kroeger.

According to the study, a one-time investment of $150 million that would fund the construction of 100 miles of oyster reefs in the northern Gulf of Mexico would return twice that amount in terms of goods and services produced in the local economy. An estimated 240 jobs per year will be supported during the expected 10-year construction phase, offering a boost to struggling coastal communities, in some of which 80 to 90 percent of household income comes from seafood-related jobs.

“All the recent studies concerning the value of a healthy Gulf make it clear that restoration is the gift that keeps on giving,” said Cindy Brown, Director of the Gulf of Mexico program for The Nature Conservancy. “From helping to create jobs and increase protection for coasts and communities, restoring the Gulf's natural infrastructure — oyster reefs, marshes, coastal forests — could be a valuable and lasting investment in the prosperity of Gulf Coast communities.”

Funding for such restoration projects can come through partnership programs, such as NOAA’s Community-based Restoration Program, and potential fines from the Deepwater Horizon oil spill. If the RESTORE Act currently under consideration in Congress becomes law, for example, 80 percent of fines would be directed toward economic and environmental restoration in the Gulf.


The Nature Conservancy is a leading conservation organization working around the world to protect ecologically important lands and waters for nature and people. The Conservancy and its more than 1 million members have protected nearly 120 million acres worldwide. Visit The Nature Conservancy on the Web at www.nature.org.

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