Lacustrine wetlands are those associated with lakes. The wetland area associated with lakes is often delineated as the outer most edge of emergent or submergent vegetation in the lake, and upland from waters edge to the point where hydric soils are no longer prevalent. The underlying geology, glacial land formation, lake currents, and fetch are some contributing factors that determine the type of wetland that will form in a given area. Variation in these factors results in the formation of a wide variety of wetlands that differ spatially, structurally, and functionally. To be considered a wetland of a large lake, a surface water connection between the wetland and lake is not necessary. Instead, wetland hydrology must be, to some extent, controlled by the lake. Groundwater linkages often play an important role in coupling lake and wetland processes. Hydrologic factors of large lakes are central to the structure and function of associated wetlands. However, wetlands only form where there is sufficient protection from hydrologic energy to allow rooted macrophytes to establish. Where wetlands do form, waves, long shore currents, and storm surges create distinct plant zonation while washing away and depositing organics. The amount of energy reaching the outer portion of the wetland is related to fetch and bathymetry. Specialized vegetation can withstand relatively high energy shorelines. The cumulative influence of stems creates drag which dampens energy to some extent shoreward. Therefore, wetlands associated with large lakes often contain predictable gradients of chemical and physical conditions from open water toward shore. Dense vegetation dampens the wave impacts, but pelagic water is forced into the outer edge of the wetland, creating a chemical or physical signature comparable to that of the open water. At the other extreme, areas of the wetland closest to shore receive little pelagic water, but instead receive a groundwater component that creates a very different chemical or physical environment. These two extremes in chemical or physical conditions merge along a natural gradient perpendicular to the shoreline, and the biota respond to this gradient. These systems are extremely complex, and therefore, understanding the processes taking place within these systems is currently a discipline of its own.