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 led by the University of Cambridge conducted an in-depth study of oyster reef area 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', published today in Proceedings of the Royal Society B, presents the first truly quantitative estimates of decline in oyster habitat over such a large spatial and temporal scale.
The findings show that while that oyster reef area declined by 64% over the last century, the total biomass, or living weight of oysters on reefs, had dropped by 88% during this period, revealing that simple physical area is an unreliable indicator of habitat status.
The good news, according to lead author Dr. Philine zu Ermgassen of University of Cambridge, is that the study gives a much-needed historical picture of conditions in specific bays and estuaries, something that will aid in future restoration efforts.
"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. Manage
|Contact: Philine zu Ermgassen|
University of Cambridge