Habitat projects protect rare butterflies in Southwest Michigan

EMMA OGUTU
LANSING — Two nature restoration projects in Southwest Michigan are rejuvenating wetland habitats as a hospitable home for endangered species, including one of the world’s rarest butterflies.

The work, including removal of invasive plants with herbicides and the controlled burning of encroaching shrubs and trees, was a collaboration of public agencies and a nature conservation group.

“We’ve been working in the Southwest region for a long time, and like most of our projects, we had earmarked this region as an ecological priority for biodiversity preservation,” said John Legge, the conservation director of the Nature Conservancy’s West Michigan office in Comstock Park.

The projects, which began in 2003, were a joint effort of the Michigan Department of Transportation, (MDOT), U.S. Fish and Wildlife Service, Department of Natural Resources and Environment, (DNRE) and the Nature Conservancy to preserve and improve the Blue Creek Fen in Berrien County and the Paw Paw Prairie Fen in Van Buren County, both in the Paw Paw River Watershed.

These efforts, which were recently honored with an Exemplary Ecosystem Initiative award from the Federal Highway Administration, started when MDOT purchased property near the Blue Creek Fen for the expansion of a highway.

“When we realized that this property was home to one of the endangered butterfly species in Michigan, we initiated a series of talks which led to the dedication of the land to DNRE for conservation work,” said Paul South, manager of the MDOT’s Transportation Services Center in Coloma.

The Blue Creek Fen is one of the last remaining habitats for the Mitchell’s satyr, according to state officials.  The chocolate brown, medium-sized butterflies are found in only 16 habitats in Michigan.

The fens are home to two other rare species, the Eastern massasauga rattlesnake and Eastern box turtle.

“The Mitchell’s satyr butterfly has been rare for as long as we’ve known about it,” Legge said.  “It has very specific requirements for certain types of wetlands, and we think that human activity has reduced the number of habitats available for the butterfly.”

Fens, their natural habitat, are rare, according to Doug Landis, an entomologist at Michigan State University.

Landis, who is involved in the preservation of the species, said the alteration of natural habitats for development and the abandonment of old conservation practices have led to factors that endanger the butterflies.

“Fire, which was used in the old days to reset the natural succession of prairie fens, is no longer used these days,” Landis said.  “In the absence of fire, woody and shrubby habitats have surrounded the fens, trapping and isolating the butterflies and leading to inbreeding.”

Landis said that inbreeding reduces the genetic diversity of species, which limits their adaptation to changes in their habitats, and, most importantly diseases.

Landis and his team are investigating whether a type of bacteria, discovered in the satyr is leading to its inability to produce viable offspring.

The Nature Conservancy is using technological advances to identify fens that have been invaded by non-native species.

Legge said staff identifies and tracks non-native plants using satellite data and high-altitude photos.  The conservancy also uses remote sensing to identify healthy habitats and those that need conservation work.

According to Landis, one way to improve the population of these butterflies is to restore the fens’ natural ecosystem functions.

Activities such as removing and controlling the regrowth of invasive species and sustaining the underground water that feeds the wetlands are part of the work that the partners undertook to restore the wetlands at both sites.

Landis and his team are working on research to promote repopulation of endangered species in other fens.

“We are looking to see what happens if we breed these species in our labs and then release them in such fens – perhaps this will help to improve their genetic diversity,” Landis said.

This strategy, referred to as “captive rearing and release,” has succeeded with large mammals such as tigers and cheetahs and other types of insects, he said.

For example, the Toledo Zoo used that technique to repopulate the endangered Karner blue butterfly, which disappeared from its habitat more than two decades ago.

“There’s only a few of the Mitchell’s satyr butterflies in the world,” said Landis.  “This is one of our global strongholds here in Michigan and we have a huge responsibility to preserve it.”

© 2011, Capital News Service, Michigan State University School of Journalism. Not to be reproduced without permission.