Lake as one of North America's preeminent natural areas, "…a famous hunting ground for aquatic wildlife...where the plants form one of the most remarkable assemblages of aquatics in the country...no body of water of equal size can boast such a list." It is still an extremely unusual and diverse area. On August 23, 2002, more than 150 experts in botany, zoology and related ecological fields assembled at Wolf Lake and in the surrounding forest, prairie and marshland to identify and record as many living organisms as possible within a single 24-hour period. The purpose of this undertaking, known as the Calumet Bioblitz, was to document the extraordinary biodiversity of green pockets that have survived within the urban and industrial landscape south of Chicago. The water in Wolf Lake was about 18 inches higher until 1998 when the Illinois Department of Natural Resources removed several beavers and their dams that had been built across Indian Creek. The subsequent drop in water depth encouraged weed growth and changed fishing conditions. Beaver signs indicate that there are beavers on the lake currently. Fish Wolf Lake is home to the endangered Lake sturgeon (Acipenser fulvescens) and the threatened Banded killifish (Fundulus diaphanus). Birds The lake and neighboring wetlands provide nesting sites for the endangered black-crowned night heron, little blue heron, yellow-crowned night heron and yellow-headed blackbird. Native Trumpeter (Cygnus buccinator) and Tundra swans (Cygnus columbianus) and non-native Mute swans (Cygnus olor) may all be found on the lake in winter. Tundra swans are absent in summer as they migrate to the arctic and subarctic to nest, however, the non-native, Eurasian Mute swans, which stay in the area year round, compete for habitat with the non-migrating Trumpeter swan population and is an impediment to restoration of the native trumpeters around the Great Lakes. Flora The endangered false golden sedge (Carex garberi), little green sedge (Carex viridula) and the threatened marsh speedwell (Veronica scutellata) are plants that grow in the neighboring wetlands. Perhaps the most amazing biological aspect of the lake is its array of rare aquatic plants. Ecosystem restoration A $7.25 million ecosystem restoration project for Wolf Lake was carried out by the Chicago District of the U.S. Army Corps of Engineers, with the support of the Illinois Department of Natural Resources and the City of Hammond. Completed in September 2007, the project sought to improve the overall quality of the lake ecosystem for native