A federal report says the Great Lakes region was the only area that gained wetland acreage during a five-year nationwide survey. The study ended in 2009.
Experts took measurements with satellites and field photography. They found that the eight-state region gained 13,610 acres, while ocean coastal areas lost more than 360,000 acres.
Scientists say the Great Lakes' gains resulted partly from lower water levels, which enabled wetlands to form along the shores. But they also credit programs that spent millions of dollars restoring wetlands that were drained or filled for farming, housing and other development.
One example is Erie Marsh near Monroe, where fish passages are being improved and nearby croplands are being converted to wetlands.