Spotlight on shrinking oyster reef
A British-American team of researchers led by the University of Cambridge in the United Kingdom has performed a quantitative assessment of an oyster reef area, the first ever study of its kind. Working with the Nature Conservancy and other research institutions and management agencies, the Cambridge group determined the actual biomass, or living weight, of oyster reefs in various estuaries across the United States. Their work, presented in the journal Proceedings of the Royal Society B, will help intensify efforts being made for coastal restoration. The oyster habitat has taken a hit over the years, on both a spatial and temporal scale. Researchers pointed out that total biomass has shrunk by 88 % over the last century, while the oyster reef area has decreased by 64 %. They noted that a simple physical area is not a reliable indicator of habitat status. Commenting on the results, lead author Dr Philine zu Ermgassen from the University of Cambridge said the data offers us a much-needed historical picture of conditions in specific bays and estuaries, which in turn will lead to stronger restoration activity. 'Oysters were 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 Dr zu Ermgassen. 'Although somewhat unfamiliar to us here in Europe, the humble oyster was once so numerous, both here and in the United States, that it formed large physical structures - oyster reefs - that rose up in banks off the sea bed. 'Using meticulous records compiled 100 years ago, we have been able to accurately quantify the changes in oyster reefs over time. Anecdotes have been converted to hard facts. Of course there have been huge losses in area, but that is only part of the story. We've also noted changes in density and structure of the remaining oysters, such that what is left is a much depleted habitat. Managers and scientists need to pay closer attention to density when setting restoration or conservation objectives.' Dr Mark Spalding from the Global Marine Program at the Nature Conservancy, one of the authors of the study, said the study will both support and inspire restoration. It should be noted that the United States is leading the way across the globe for making a positive impact on these habitats. Various estuaries for the restoration of oyster habitat are already being revamped. 'This is a call to action, and these findings will provide funders and managers with a powerful baseline - a clear vision of how things were - and an opportunity to establish meaningful goals and targets,' Dr Spalding said. 'The findings have implications beyond oyster reefs, however. 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. 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.'For more information, please visit: University of Cambridge:http://www.cam.ac.uk/Royal Society B: Biological Sciences:http://rspb.royalsocietypublishing.org/
Countries
United Kingdom, United States