Restoring this depression so it could hold water again allowed wetland plants and animal species to return. In 1991, drainage tiles were cracked and removed, and the wetland once again held water. Wetlands provide wildlife habitat, with an estimated 900 North American species of mammals, birds, reptiles, amphibians, and fish dependent on them for food, cover, habitat, or spawning grounds. They also store excess water and release it slowly to protect downstream areas, and wetland plants filter pollutants and sediment so water leaving a wetland may be cleaner than the water that entered it. Although this region is known for its lakes and wetlands, many wetlands were drained beginning in the mid-1800s to convert them to productive farmland. Wetlands once covered nearly 6 million acres in Indiana, but drainage tiles removed water and made them tillable; by 1882, Indiana farmers had installed over 30,000 miles of clay drainage tiles. With the water's return, saturated soil and lack of oxygen around roots killed trees, creating dead snags that provide nesting sites for woodpeckers and swallows. One animal now found in the wetland is the Blanding's turtle, a State Endangered species that can be seen sunning itself on logs in summer, with a long neck and bright yellow throat.