New Research Measures Economic Losses from Further Declines in Submerged Aquatic Vegetation in the Albemarle-Pamlico Estuary

Raleigh, NC

Through funding from the Albemarle-Pamlico National Estuary Partnership (APNEP), an interdisciplinary team of researchers at NC State University and Duke University have published a report that estimates the market and nonmarket economic losses from declines in submerged aquatic vegetation in the Albemarle-Pamlico estuary.  Focusing on the losses to commercial and recreational fisheries, residential property values, and carbon sequestration, the team conservatively estimates aggregate losses of $1,290 per acre over the next decade.

“Aquatic grasses are declining worldwide, and the Albemarle-Pamlico Sounds is no exception,” says APNEP Director Dr. Bill Crowell. “We should be concerned about not only the ecological impacts of this loss, but the economic effects as well.”

Submerged aquatic vegetation (SAV), also referred to as underwater grasses or seagrasses, grows in estuarine environments.  Many aquatic species that are important to commercial and recreational fisheries use SAV for habitat, food, and nurseries.  SAV also filters nutrients, prevents erosion, and sequesters carbon, all of which generate valuable ecosystem services. These services make SAV a vital contributor to the health of estuarine ecosystems and coastal communities. 

In recent decades, factors such as coastal development and declines in water quality have led to declines in SAV coverage both globally and in North Carolina.  A recent APNEP report detailing the results of SAV mapping of the high salinity parts of the Albemarle-Pamlico estuary found that SAV coverage declined by 5,686 acres (or 5.6 percent) between 2006 and 2013. 

“This SAV generates substantial economic value to commercial fishermen, recreational fishermen, homeowners, and society at large.  If current trends in SAV loss continue, these groups will suffer.  Our study attempts to put a dollar value on these losses over the next decade,” says Dr. Roger von Haefen, co-Principal Investigator on the project and Associate Director of the Center for Environmental and Resource Economics Policy (CEnREP) at NC State University.

The researchers considered four SAV-loss scenarios in the Albemarle-Pamlico estuary that assumed annual SAV acreage losses ranging from 0.5 to 5 percent over the next decade.  For each scenario, they constructed commercial and recreational fishing loss estimates by combining forecasts from biological models of total catch for three species with economic models of commercial fishermen’s profits and recreational fishermen’s willingness-to-pay to catch additional fish.  For residential property value impacts, they combined assessed values for all nearshore single and multi-family properties, detailed maps on the location of SAV beds in the estuary, and peer-reviewed estimates of how proximity to SAV is capitalized into property values.  For carbon sequestration losses, they valued the decline in carbon sequestered by SAV using the federal government’s social cost of carbon which captures both market and nonmarket economic damages from the release of greenhouse gasses. 

The researchers found that a 0.5 percent annual decline in SAV acreage over the next decade will generate total economic losses of $8.6 million in 2019 dollars.  If SAV acreage loss were to accelerate to 5 percent per year, they estimate total economic losses of $88.7 million.  In both cases, over half of these losses arise from declines in carbon sequestration.  Moreover, both scenarios imply that economic losses over the next decade on a per acre basis are roughly $1,290.

Although these losses are economically significant, Co-Principal Investigator Dr. Sara Sutherland emphasizes that they are by no means comprehensive. “The full social cost of losing an additional acre of SAV is larger than our estimate.  Due to data gaps and limitations with our scientific understanding of how SAV provides ecosystem services such as erosion control and waterfowl habitat, we could not quantify all benefits.  Moreover, our commercial and recreational fishery benefits are conservative because we only considered three species.  Hopefully, future research will generate new data and scientific insights that will allow us to provide a more complete estimate of economic losses.”

“APNEP will use this information to further convey to decision makers and the public the importance of protecting and restoring North Carolina’s SAV resource,” states APNEP Director Dr. Bill Crowell.

In addition to von Haefen and Sutherland, Dr. David Eggleston and Dr. Jie Cao of NC State University co-authored the report which can be accessed here. To learn more about SAV in the Albemarle-Pamlico estuary, visit APNEP’s SAV Monitoring webpage, or contact Dr. Tim Ellis, APNEP’s Quantitative Ecologist, at tim.ellis@apnep.org.  For more information about this research study, please contact Dr. Roger von Haefen at rhhaefen@ncsu.edu.

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