Smithsonian researchers develop models to assess wetl...( Healthy wetlands perform vital ecolo...)

Healthy wetlands perform vital ecological functions in a watershed. But assessing their condition and ability to perform those functions is not easy, especially as wetlands are disappearing fast due to human encroachment.

In a special issue of the journal Wetlands, Smithsonian scientists report a promising method of wetland assessment that will help environmental managers quickly take stock of wetlands across an entire watershed. Tools for this kind of rapid watershed-scale assessmentrelying on a few easily measurable key factorshave been previously unavailable to managers.

In three papers, Dennis Whigham, Donald Weller and Thomas Jordan of the Smithsonian Environmental Research Center and their colleagues present the results of a large-scale study that combines field studies and remote-sensing data to assess the ecological functioning of wetlands in a landscape.

The researchers based their study on an approach previously developed for assessing individual sites, called the Hydrogeomorphic (HGM) approach, in which ecological conditions are inferred from readily observable indicators, such as plant species present and the degree of human disturbance.

We took these methods for assessing wetland functions and expanded them to a whole-landscape scale, which is something that has not been effectively done before, said Whigham, who coordinated the project. These days, most land managers are not asking how to understand what is going on in an individual wetland, they want to manage resources at a much larger scale.

Wetlands are important buffers for flood control, can absorb pollutants and excess nutrients and provide critical habitats for many plants and animals, including some threatened and endangered species.

For this study, the researchers focused on non-tidal wetlands in the Nanticoke River watershed of Maryland and Delaware. Draining into the Chesapeake Bay, the Nanticoke system is one of the most biolog
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