Wetland plants are an essential component of all wetland ecosystems. Most wetland plants are flowering plants. Wetland plants evolved from terrestrial plants and retain many features of upland plants. However, they differ from upland plants in their ability to survive with little to no oxygen in the root zone, or to float free, without roots in the substrate. Wetland plants have evolved a number of strategies to withstand flooded, anaerobic sediments, most notably the formation of porous root and stem spaces, called aerenchyma, where gases can diffuse more freely. Plants that spend their lives underwater display adaptations to low light and low carbon dioxide levels. Wetland plants retain the same sexual reproduction strategies of upland plants, with aerial flowers that are mostly insect or wind pollinated. Asexual reproduction tends to dominate in wetland ecosystems, particularly those dominated by large stands of monocots such as common reed or cattails. The primary productivity of marshes tends to be quite high in comparison to other ecosystem types. Wetlands with fewer nutrient inputs or in cold climates have lower primary productivity. Temporal changes in plant community composition, called ecological succession, are a result of both internal (e.g., peat accumulation) and external (flooding) processes. Disturbances, such as fires and storms, often maintain the current plant community or reset it to an earlier successional stage. Invasive species have become a great concern in many wetland ecosystems, where they can have deleterious effects on the native plant community, wildlife, and human activities. Wetland managers use plants as indicators of jurisdictional boundaries and for bioassessment. Both delineation and bioassessment integrate community dynamics and the landscape context of wetlands, and represent the application of wetland plant ecology.
Cronk, J.K. and M. S. Fennessy. 2008. Plants of Wetlands. Encyclopedia of Inland Waters, G. Likens, editor-in-cheif. Elsevier Limited, Oxford, UK.
Encyclopedia of Inland Waters