Stage : The Crucial Role of Macrophytes in Regulating Trophic Interactions in Shallow Lake Wetlands

Hydrophilie, or water-Ioving, macrophytes characterize wetland ecosystems, indicating prerequisite conditions of hydrie soils and sufficient hydrology. The presence of such macrophytes is a key descriptor in multiple wetland definitions (Lewis 2001a) and macrophytes may be further used to actually describe partieular types of wetlands, such as cattail marshes. Macrophytes contribute significant biomass to wetland systems and represent a critieal component of wetland biogeochemistry as primary producers and drivers of organie matter cyeling within aquatie systems. In this chapter, we argue that macrophytes occupy the center of trophie interactions in shallow lakes, influencing outcomes through structural, behavioral and chemieal interactions. We define shallow lakes as permanently flooded wetlands that often contain submerged or floating macrophytes and that may be surrounded by emergent vegetation (i.e. marshy habitat). Shallow remains a relative term in limnology cireles, but typieally is less than 3 m average depth, such that macrophytes can ftll a substantial portion of the water column and stratification is neither predietable nor long-term. Such systems may be termed lakes, ponds or wetlands, depending on their size and the ecologieal context. Macrophytes may regulate trophie interactions in ephemeral systems without permanent inundation.