The assessment of herbaceous plant cover in wetlands as an indicator of function

In the United States, wetlands are often created (as compared with restored) as mitigation for damage done to natural wetlands by development or other activities. There is increasing concern that these created sites do not function as do natural wetlands, even after a period of years. Monitoring of these created wetlands often consists of an assessment of the percent herbaceous plant cover as some indicator of the functional success of the wetland. However, it is not at all clear that assessment of herbaceous cover translates into an accurate indicator of wetland function. In this paper I review several functions commonly ascribed to wetlands and assess the reported relationship of percent herbaceous cover to those functions (if any). Of six functions reviewed, only one has a probable (though indirect) positive relationship with the percent herbaceous plant cover on a site. More useful assessments of wetland function might be made with other structural indicators, such as basin morphometry, tree density, or basal area.