Alligator River National Wildlife Refuge: Serving as a 150,000-acre laboratory for evaluating impacts, testing adaptations, and recording observations relating to climate change
Currently, two research projects relating to climate change are underway on Alligator River National Wildlife Refuge. The first is a partnership between The Nature Conservancy and the U.S. Fish and Wildlife Service to evaluate the effects of several types of adaptive management on an area severely impacted by sea level rise. The second project is a research effort focusing on carbon and nitrogen cycling within swamp forest ecosystems.
The Nature Conservancy and U.S. Fish and Wildlife Service: Partners for Coastal Resilience -- an Adaptive Management Study
Alligator River National Wildlife Refuge was established in early 1980s with aid from The Nature Conservancy. Today, the refuge encompasses more than 258,000 acres in Dare and Hyde Counties. However, accelerated sea level rise threatens the entire refuge. The Conservancy’s climate change adaptation project will take several steps to make the fragile shoreline more resilient to encroaching seas. Adaptation strategies include: restoring the hydrologic regime and associated wetland systems, while limiting saltwater intrusion to maintain necessary soil moisture and promote carbon sequestration benefits of peat soils; planting salt-tolerant species in advance to sea level changes to ensure a resilient shoreline in the future; and building oyster reefs to buffer shorelines from waves and storms.
Part 1 - The refuge landscape has been dramatically altered by humans, making rising sea levels a more pressing problem. There is an extensive network of ditches that allow the wind-tide-driven systems to jet brackish water much further into the interior than is natural. This project will look at the surface water drainage patterns, how they have been altered and what can be done to restore them, while attempting to hold salty sea water at bay.
Part 2 - While the refuge is threatened by saltwater intrusion, shoreline erosion also is accelerating. In an ideal world, the transition from forest to marsh should equal the rate of erosion of the marsh on the shoreline, but we don’t live in an ideal world – even marsh vegetation is feeling and will continue to feel the pinch. This part of the project will plant salt-tolerant species such as bald cypress, black gum and green ash to buffer rising seas.
The effects of rising sea levels may be lessened by construction of oyster reefs. As waves from storms pass over the reefs, their energy is dissipated, thus reducing erosion on the adjacent shore. Oyster reefs also play a role in carbon sequestration, because they are made of a form of carbon – calcium carbonate.
“It has been a long, hard road. Now we can do something. You have two choices – throw up your hands and say there is nothing I can do, or you can say, gee, this is an unprecedented opportunity. My choice is the latter,” says Dennis Stewart, Alligator River National Wildlife Refuge biologist. “We’re going to do something that will help set the stage for future generations to work from and serve as a model for other agencies and organizations, and the hope is that we can learn something here that will have local, regional, national, and even global applications.”
Dr. Asko Noormets climbing the monitoring tower to attach an array of instruments to it. Credit: Dennis Stewart, USFWS.
“If native plants and animals can’t readily adapt to a rapidly rising sea level, a catastrophic loss of habitat and species may very well occur,” says Brian Boutin, director of the Conservancy Climate Change Adaptation Project. “Hopefully, we’ll find that we are giving the environment a jump start to adapt as sea level rise begins to accelerate”
The Nature Conservancy and the U.S. Fish and Wildlife Service are working together to give Alligator River National Wildlife Refuge more time in the face of a rising sea. Lessons learned on this refuge can and will be used elsewhere, including other refuges in the Albemarle region, such as Pocosin Lakes and Mattamuskeet National Wildlife Refuges.
Carbon Sequestration (Carbon/Nitrogen Cycle Monitoring)
The second research project relative to climate change on Alligator River Refuge is investigating the fundamental processes of ecosystem respiration in lower coastal plain forests. Researchers will be evaluating how the nitrogen and carbon cycles are affected by changes in climatic factors and in the water table, which will be used as models for predicted climate change and sea-level rise, respectively. The work will be conducted in forests of the lower coastal plain of North Carolina over a period of several years. Drs John S. King and Asko Noormets from the Department of Forestry and Environmental Resources at North Carolina State University are the principal investigators for the project.
Dr. John King talking to a group of international scientists visiting the tower site during a conference field trip dealing with forestry and climate change. Credit: by Dennis Stewart, USFWS.
Submitted by Bonnie Strawser, Alligator River NWR, North Carolina