More acres on coast due to low lake levels may mask the real long-term problem
By MATTHEW HALL
Special to the Record-Eagle
LANSING — A large gain in the size of Michigan’s coastal wetlands between 2004-09 may obscure much larger, longer-term losses that are likely to continue, experts say.
The Great Lakes region gained 13,000 acres in the five-year period, according to a report by the U.S. Fish and Wildlife Service and National Oceanic and Atmospheric Administration, but much is due to low levels in the Great Lakes.
The report highlighted how the rate of coastal wetland loss across the United States is increasing.
Public and private efforts to preserve wetlands also added small gains, but researchers and state regulators cautioned that those gains need to be put in the context of a long-term overall loss of wetlands in Michigan.
Chad Fizzell and his colleagues at the Department of Environmental Quality analyzed inventories of wetland coverage from 1978, 1998 and 2005.
“We now have some idea of gains and losses over the whole state, including the inland wetlands,” Fizzell said, adding the information will go into a report in the coming months. “What we’re seeing is a pretty definite loss over that 30-year period — between 50,000 to 75,000 acres of loss.”
Wetlands are a vital part of the environment; they provide habitat for fish and animals and filter out pollutants that run off the land, said Donald Uzarski, the director of the Institute of Great Lakes Research at Central Michigan University.
Some of the most important wetlands in the Great Lakes region include Michigan’s Grand Traverse Bay, the Les Cheneaux Islands in Mackinac County and the diverse river mouth wetlands in Manistee County, he said.
Uzarski said gains along the coasts largely can be attributed to unusually low Great Lakes water levels over that same five-year period.
“As the shoreline moves away from the upland, the wetland essentially follows it,” Uzarski said. “Usually, the amount of wetlands stays the same over the years as water levels rise and fall because wetlands move to where the shoreline is. But we’re seeing low levels that have rarely happened in the past.”
Moreover, as shorelines have been developed for urban and suburban expansion, inland movement of wetlands is blocked if lake levels rise, he said. “If we develop a shoreline — put in a seawall, a parking lot, a hotel — that wetland can no longer migrate toward land.
Low water levels also prompt growth of invasive plants, such as phragmites. In some cases, invaders have overrun entire wetlands areas.
Phragmites are reed-like plants not native to Michigan and do not provide much of the environmental value supplied by natural wetlands. However, they do fulfill several important functions, such as taking up toxic substances and removing them from the ecosystem.
The long-term loss has amounted to about 40-50 percent of the natural wetlands Michigan historically had. For example, Saginaw Bay has lost 95 percent of its wetlands, even though it remains a major wetland area.
Matthew Hall writes for Michigan State University’s Capital News Service.