Saturday, May 20, 2006

Canada Geese and Anacostia Wetlands

The Anacostia River has long suffered from neglect and pollution. Just recently it was branded as one of the most polluted rivers in America, after up to 68% of brown bullhead catfish from the river were discovered to have liver tumors. In the last few years, the District government has focused on ways to clean up the river and "revitalize" the waterfront.

A large part of the publicity has focused on economic development, which is being overseen by the Anacostia Waterfront Corporation, a semi-public entity. The economic development includes the new baseball and soccer stadiums being built at the mouth of the Anacostia, as well as other initiatives. Somewhat less publicity has been given to efforts to restore the Anacostia wetlands that formerly provided habitats for many animals and would improve the water quality dramatically by removing excess nutrients.

Over a decade ago, the wetlands of Kenilworth Marsh were rebuilt into a healthy ecosystem. Now, the focus is on Kingman Lake. Since 2000, there has been a major effort to replace the wetlands south of Benning Road that were destroyed by an Army Corps of Engineering project in the early twentieth century. Initially the restoration program was successful; the ground was built up, native marsh grasses were planted in fenced areas, and the plants thrived. But this did not last last when fences were removed.

This week's Washington City Paper has profiled one of the major challenges in restoring the former wetlands on the Anacostia: resident Canada Geese. Whenever fencing around replanted grasses came down, either because it was removed or because it fell down, geese would enter the replanted areas and eat down the grasses. In the second year of the project, geese ate 80% of the area that had been replanted the year before. What is worse, the resident geese eat the grasses all year, including in the summer when the same plants could be used by bitterns, rails, and other migratory marsh birds. The resident Canada Geese are a midwestern subspecies imported for hunting in the 1950s; it is the largest subspecies, Branta canadensis maxima, and it is extremely sedentary.

One measure of the success of marsh restoration is the success of wild rice, a dietary staple for both songbirds and gamebirds. Unfortunately, the Canada Geese love wild rice as well, and will eat the plants down - grains, leaves, stems, and all. Planting unpalatable species might discourage the geese, but would likely have the same effect on the animals the restoration is supposed to attract.

The options to solve the population issue all have problems. The current situation - spending millions on replanting only to have the plants mowed down - is clearly not tenable. Scaring away geese with dogs and various noisemakers only works temporarily; geese come right back as soon as the show is over. Egg addling will keep the population in check, but will not lead to a significant decrease for some time; this option has been in use for several years already. Lethal control, an option now under consideration, would reduce or eliminate most resident geese, has its own ethical questions and would certainly face public opposition and lawsuits.

What will happen with the marsh restoration project remains to be seen. Rebuilding the Anacostia wetlands is a key part of restoring a healthy river. Because the river is part of the Chesapeake watershed, improving water quality here has a regional impact as well. Unfortunately the project cannot make significant progress with the current balance.