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Researchers explore ways to give amphibians rights of way

Story by: Sarah Scully

Kathleen Trauth, an associate professor in the civil and environmental engineering at the University of Missouri, and Ray Semlitsch, a curators’ professor in biological sciences at MU, aim to guide future rights-of-way (ROWs) designs and placement of mitigation wetlands. They also plan to create experimentally proven methods to relocate rare, declining or imperiled amphibian species.

The project began when Chris Shulse, a roadside manager at the Missouri Department of Transportation (MoDOT) who also is a biological sciences doctoral student in Semlitsch’s lab, mentioned interest in a project connected to roadside management of habitats to her mentor. MoDOT is required to mitigate any impacted or destroyed wetlands that result from construction. The two approached Trauth with the topic, and a grant application was sent to the EPA.

The study is primarily funded by EPA’s Water, Wetlands and Pesticides Division and matched by the Missouri Department of Transportation (MoDOT), who provided the researchers with test wetlands.

The research

Semlitsch and Trauth’s research is two-pronged. Semlitsch focuses on the amphibians, while Trauth looks at applying the information for MoDOT.

On Semlitsch’s side, research will go through three phases. The first step is studying and analyzing the effectiveness of current man-made wetlands. Of particular interest is amphibian health. Semlitsch and Shulse studied amphibian populations at sites across northern and central Missouri. The sites included MoDOT wetland mitigation sites and “wildlife ponds” constructed at Missouri Department of Conservation areas.

Phase two of the study was the construction of new experimental wetlands. The experimental wetlands tested specific characteristics of man-made wetland’s design.

Amphibians’ needs are often poorly understood or overlooked when it comes to wetland designs. “Historically, among vertebrates, they have been understudied because they’re less visible,” said Semlitsch, who specializes in ecological studies of amphibians.

In the third phase of the project, rare or declining northern Missouri amphibian species are moved to the newly created experimental wetlands, though there is no guarantee that the relocated amphibians use the site.

The engineering portion consists of analysis using a geographic information system (GIS).¬† The GIS analysis will use Semlitsch and Shulse’s research to determine the extent to which various combinations of landscape parameters (land cover, roads, streams) at varying distances from the wetland are associated with habitats that support amphibian health.

Trauth’s doctoral research assistant in civil engineering, Miriam Romero, has quantified these landscape characteristics and is performing analyses to understand the relationships. She is using a normalization process resulting in dimensionless ratings in order to be able to combine parameters that have different measurement units (e.g., acres and feet). In the end, equations that take into account the landscape parameters and amphibian health will describe what goes on in the wetlands.

The set of equations resulting from the analysis of characteristics and their occurrence at different locations in the landscape and in combination with other wetlands will be used to develop a guidance document for MoDOT to make transportation improvements on ROWs that will have the least detrimental impact on amphibian habitat.

Amphibians & wetlands

Because birds and other vertebrates are more visible than amphibians, they were studied much earlier and intensely. “Amphibians are very secretive. Many of them live underground, and almost all of them are nocturnal,” Semlitsch said. Few proven techniques were developed for capturing and observing amphibians.

“While our knowledge of birds and mammals has increased during the 1900s, until the 1960s and 1970s, we still knew very little about the basic biology of amphibians,” Semlitsch said.

About 30 species of pond-breeding frogs and salamanders live in Missouri, and Shulse and Semlitsch looked at about 12 of the more common species in northern Missouri.

Because amphibians are migratory animals, barriers such as roads and development between the spring breeding grounds and the terrestrial homes the rest of the year can affect them as they migrate  hundreds of yards between the two locations.

The wetlands where amphibians spend the breeding season are important ecosystems. “Wetlands serve an important function for humans,” Semlitsch said. “Wetlands are really a filtering system and a reservoir for water. We tend not to think about that.” All the water that falls from the sky and flows downhill collects in wetlands. Biological organisms in water, like algae, tadpoles and salamanders, purify and filter the water.

Wetlands also have many other functions. “They’re also active for recreation, for observation and hunting. They can serve as a buffer to lessen the impact of floods or can be a storage facility (for water),” Trauth said.

The research and analysis will end up being applicable to Midwest and possibly to eastern North America as well,” Semlitsch said. Species of amphibians that were studied in Missouri also occur throughout eastern North America. “The idea is to look at the general principles that can be applied more broadly,” he added. “Whether it’s Missouri or Iowa or Minnesota or Ohio, over the last century between 50 percent and 80 percent of all wetlands that naturally occured have been lost.”

Currently every acre of wetlands habitat impacted or destroyed by road expansion or development must be recreated. Semlitsch and Trauth’s research will help MoDOT to create more efficient and amphibian-friendly environments.

At the completion of the project, the two graduate students will create a document to offer guidance to future MoDOT habitat mitigation projects.