Palustrine wetlands were formed approximately 10-14 thousand years ago in the wake of retreating glaciers. Lacustine wetlands are found in the shallow protected areas of lakes larger than 20 acres with water depth in the deepest part of the basin exceeding 6.6 feet. The wetlands in this system extend from the lakeshore to the point where, at low - water stage, the water is 6.6 feet deep. These wetlands are typically subject to less water level fluctuation than those of the palustrine system. These wetlands are found in Iowa along protected shores of Spirit Lake, Clear Lake, and many smaller lakes.
Wetlands occupy a transitional position between terrestrial ecosystem and aquatic ecosystems.
Wetlands act as buffers between urban development and groundwater resources. Wetlands are important in maintaining the quality of groundwater resources. Eared grebe, great blue heron, great egret, black crowned night heron, American bittern, bald eagle, king rail, and Forster's tern. Groundwater recharge, flood storage, shoreline anchorage, erosion protection, sediment trapping, habitat for wildlife, food chain support. Iowa Association of Naturalists.