UNIVERSITY PARK, Penn. -- To most folks, wetlands are marshy ponds with a duck or two floating on the water. To Robert Brooks, associate professor of wildlife ecology in Penn State's School of Forest Resources, "all wetlands are not created equal," and the results of a three-year study of 51 natural wetland sites in Pennsylvania have shown this to be true.
Brooks, director of the Penn State Cooperative Wetlands Center, says Pennsylvania is losing hundreds of acres of wetlands per year to development and other uses. Simultaneously, state agencies, private companies and private citizens are restoring or creating hundreds of wetland acres each year. The project, funded by the Pennsylvania Department of Environmental Protection and the U.S. Environmental Protection Agency, Region III, gives agency employees and other professionals specific guidelines to describe and categorize a variety of wetland types, including natural wetlands used as reference sites for researchers and mitigation projects.
A series of assessment techniques to help professionals evaluate restored or created wetlands have been developed during the study. "A wetland is an elusive thing to categorize," Brooks says. "The best way to describe our work is that we are creating a sort of template or blueprint that can best match the characteristics of a certain type of wetland to the site where you intend to replace or restore a wetland."
The project identified 51 sites as reference wetlands and categorized them into types, such as riparian depressions,headwater floodplains, mainstem floodplains, and slope wetlands. At each individual site, characteristics such as plant life, animal life, soil composition, sedimentation and basin shape also were analyzed and categorized.
"The project also extensively researched bird, amphibian and plant species that inhabit only certain wetland habitats --called indicator species," Brooks says. "To truly create or restore a wetland in a specific site, you have to match the structure and characteristics of whatever wetland type best fits the site. Otherwise, the wetland will function differently. "Brooks explains that forested wetlands fed by groundwater are the most abundant type of wetlands in the Mid-Atlantic area, and these forested areas are most commonly lost to development. If the forested wetlands are restored or created, the most common type is an open-water pond with emergent forest vegetation.
"The flora and fauna associated with forested wetlands and open-water wetlands are markedly different," Brooks says. "What this means is that some types of wetlands will be very hard to replace, and if the choice comes down to destroying a wetland, it's important to know which types can be difficult to replace."
The team's research also revealed that while different types of wetlands obviously have different characteristics, created wetlands have different characteristics from the wetland types they are modeled on. "A created wetland looks like a natural site, but it really doesn't behave like one," he says. Although Brooks says the wetlands assessment project has given resource professionals the tools with which to identify or describe wetland types, the next step to completing the portrait of the state's wetlands is understanding how wetlands function.
"What we're missing is the personality of wetlands," Brooks says. "What do wetlands do, and why do they do it?"
To find the key to the "personality" of wetlands, the Penn State Cooperative Wetlands Center is initiating another three-year wetland project, led by Brooks and C. Andrew Cole, affiliate assistant professor of landscape architecture, designed to discover how wetlands function, including how wetlands change over time and how human disturbances affect their natural progression.
"You always need more information to improve on the designs of the future," Brooks says.