520 ILCS 25/10: Purpose.

It is the purpose of this Act to provide a stable and supplemental source of money to support activities and programs undertaken by the Department or other managers of land to preserve, protect, acquire, and manage habitat for future generations. Habitat quality is measured by such parameters as type, native diversity, size, structure, scarcity, and location. Linkage with neighboring habitat, whether existing or potential, is another important consideration.

Illinois' habitat includes all wetlands, woodlands, grasslands, and agricultural lands, natural or altered, that support or have the potential to support populations of wild animals in any or all phases of their life cycles.