Vol. 2, No. 1 Contents
Headline Back Issues Winter 1997
|
Constructed wetlands revive dikelands Bay of Fundy - Filled with rich soils and topped with salt-tolerant plants, salt marshes are among the most productive habitats in the world. Intricate networks of creeks and small ponded areas called pannes link land and sea, providing nursery grounds and food for fish, waterfowl, and shorebirds. Salt marshes emerge from the tide's ebb and flow, and depend on it to function. In a process that has taken place twice a day for thousands of years in the upper Bay of Fundy, the worlds largest tides as high as 50 feet/15 meters flow in and out of the Chignecto Bay and Minas Basin, eroding the soft red sandstone there, and forming vast mud flats that eventually give rise to extensive salt marshes.
Those working on behalf of habitat restoration say converting the dikelands back to salt marsh is impractical. People have settled there, establishing homes, businesses, and the infrastructure to support them. Restoring tidal flow would flood these settlements. Alternatively, in an effort to revitalize wetland habitat for waterfowl and other migratory birds, various habitat restoration partnerships are constructing freshwater impoundments on the former agricultural lands that once were salt marsh, being careful to avoid inundating developed areas. Although flooding these lands with fresh water will never restore the lost functions and values of Fundy salt marshes, the impoundments are providing much-needed habitat for waterfowl and other wildlife such as marsh birds, amphibians, fish, and insects all essential in the food chain. "Its a win-win situation," said Jon Stone of the Canadian Wildlife Service and communications coordinator for the Eastern Habitat Joint Venture (EHJV), which is working on restoring waterfowl habitat. "Both people and wildlife will benefit," he explained. Plan promotes population growth Coupled with great losses of wetlands, drastic declines in waterfowl populations in the 1980s led to development of the North American Waterfowl Management Plan, a 15 year agreement between the US, Canada, and, more recently, Mexico. The plan provides a framework for addressing conservation and protection of critical wetland habitat throughout North America through restoration, enhancement, and land acquisition. Partnerships between governmental agencies and non governmental organizations are working to restore continental waterfowl populations to 100 million birds numbers not seen since the 1970s. In 1996, North American waterfowl numbers, including black ducks and Canada geese, were estimated at 90 million birds, an increase of 35 million since 1985. These species rely on Canada's wetlands for breeding, raising their young, and staging gathering prior to their long migration south. Collaborating to carry out the plan in Canada are members of EHJV, including Environment Canada and the Canadian Wildlife Service, Wildlife Habitat Canada, New Brunswick's Department of Natural Resources and Energy, Nova Scotia's Department of Natural Resources, and Ducks Unlimited Canada (DUC). Funding is made available through US partners, including the US Fish and Wildlife Service and non governmental organizations.
Since DUC's early work and the formation of EHJV in 1989, more than 100 wetland impoundments have been developed on nearly 20,000 acres/8100 ha of land in the Gulf of Maine watershed. Project costs have averaged about $1500 per acre a bargain considering that land acquisition and excavation of soil, both known to be expensive, are often involved. Belleisle a "model" project At Belleisle Marsh, an 800-acre/320-ha site located along the Annapolis River in Nova Scotia, several freshwater impoundments are integrated with agricultural use and private land ownership. People hiking along trails there can observe birds and wildlife, and populations of waterfowl, including Canada geese and black ducks, and other marsh birds such as sora rails and bitterns, have increased. "Before the restoration of Belleisle Marsh, I would see grasslands with very little wetland habitat. Today, I can count as many as 30 bird species within an hour," said Stone. Belleisle is also providing habitat for other wildlife dependent on wetland habitat, such as muskrat and several species of frogs. Using the Belleisle project as its flagship, the EHJV hopes to encourage private landowners and farmers to develop similar projects on their own land, as has been done in New Brunswick at the Hampton-Kennebecasis Marsh Complex. According to Peter Austin-Smith of New Brunswick's Department of Natural Resources and Energy, freshwater impoundments, rough cover habitat (areas where dense vegetation is allowed to grow), and river and lake habitat coexist with agricultural lands. "A positive outcome of this project has been increased communications between and among interest groups and government agencies," he said. And communication is essential in managing that 5000-acre/2020-ha marsh system, which includes multiple landowners who differ in their interests and opinions. The Belleisle project, Hampton-Kennebecasis Marsh, along with a 2000-acre/810-ha project proposed for the Tantramar Marsh, will serve as "models" for future projects. "The [Belleisle project] has been extremely successful, not only for wildlife, but in changing peoples' attitudes," said Reg Melanson of the Canadian Wildlife Service and Coordinator for the EHJV, adding "people are beginning to realize the benefits of these projects." Visit www.wetlands.ca for more information on wetlands in Canada. |
||||||||||
PDF Version
Gulf of Maine Council on the Marine
The construction of dikes in this region by Acadian settlers in the 1670s, however, blocked tidal flow, severing the lifeline between land and sea in many places, and converting more than half of the former salt marsh there to agricultural land. From the 1700s to early 1900s, these "dikelands" supplied hay for local use and export to the US. But when the invention of the combustible engine in the early 1900s reduced the use of horses and consequently the demand for hay these lands fell out of use for farming. And because they are no longer hospitable to salt marsh wildlife, the species that once lived there have not returned.
DUC has been working to enhance waterfowl habitat in the Gulf of Maine watershed since 1965. The group has pursued projects using a successful combination of landowner agreements and land acquisition. But, noted Keith McAloney, DUC Senior Habitat Biologist, "The EHJV partnership provides the additional money necessary to purchase land and further enhancement of wetland habitat."