Fen Resilience in Southern Michigan

In 2000, MNFI received a USFWS grant to survey for the Mitchell's satyr across Michigan. At this point, there were over 20 known satyr sites. MNFI subcontracted with SWMLC to assist with monitoring at several sites in southwest Michigan, including Branch County Fen.

The Michigan Department of Environment, Great Lakes, and Energy observed a wetland violation by a private individual in habitat occupied by the Mitchell's satyr at Branch County Fen. Together with MNFI and USFWS, talks began with the landowner who had dug ponds and cut horse trails through the fen. Rather than paying a fine for the wetland violation, the neighbor worked with partners to protect the land. This resulted in SWMLC purchasing a 15-acre section of occupied habitat with funds provided by the USFWS.

After the land deal was finalized, the first 15-acre section of the fen was protected, shown by the yellow polygon on the map. SWMLC was now a landowner of an endangered species population. The Conservancy was able to start land management by working with  Blue Heron Ministries , an Indiana-based non-profit.

Over the years, SWMLC and Blue Heron Ministries worked to create a 'corridor' to encourage butterflies to move between the core population and the southeastern pocket of the fen. This decision was fortuitous, as in later years this area would be a critically important habitat patch for the butterfly.

In 2008, regular monitoring of the site showed that the Mitchell's satyr population was dwindling.

In 2009, SWMLC conducted a prescribed burn (red shaded area on the map) with the goal to combat encroaching woody vegetation, which was shading out host plants needed by the Mitchell's satyr.

The prescribed fire was concentrated in areas where the butterfly was not found at the time. This was the first time in decades - if not centuries - that fire had returned to this landscape.

Population monitoring of the Mitchell's satyr continued, and showed that the butterfly had returned to the area burned in 2009.

Mitchell's satyrs are found throughout most of the site, although their numbers are lower than in previous years.

Habitat work aimed to created a corridor to the southeastern portion of the fen continues with funding from the Michigan Department of Natural Resources.

In a disappointing year, less than 15 butterflies were found during multiple surveys.

Notably, the southeastern fen pocket, which was once not suitable satyr habitat, now contained the core population. This area was targeted for future invasive species treatment and shrub/tree removal. This critical land management created excellent butterfly habitat which would not have existed without SWMLC action.

Surveys continued to disappoint, with population contracting to an even smaller area in the southeast portion of the preserve.

By the time SWMLC acquired an additional 24 acres (broken yellow boundary) of occupied habitat and oak upland in 2019, the butterflies were restricted to just 13 satyrs in a pocket of habitat smaller than a football field. Buoyed with financial support from the USFWS, and guided by MNFI's technical understanding of the species, SWMLC began decisive habitat restoration to bring the species back from disappearing.

Land management began in the winter of 2019-2020 as population decline led the satyr to become isolated in the southern portion. Using "surgical precision" SWMLC returned to formerly occupied habitat patches and removed just enough brush cover, while leaving important native plant species like bog birch, poison sumac, red osier dogwood, and tamaracks. Mitchell's satyr habitat preferences are often described as a "Goldilocks" scenario, with not too much shrub cover, but not too little, and just the right species of sedges near groundwater springs. The restoration crews attempted to "create" new habitat where Mitchell's satyrs hadn't been seen in years.

SWMLC and MNFI counted a small victory in the annual butterfly counts of 2020! Three Mitchell's satyr were seen in a 1/4 acre of previously unoccupied habitat that had been restored the previous winter! With enthusiasm renewed, a more extensive habitat restoration occurred in winter where crews "rolled out the red carpet" and tried to welcome butterflies into newly created habitat through use of an open flight corridor.

In April SWMLC and Blue Heron Ministries conducted several small prescribed burns on habitat that hadn't seen fire for hundreds of years. The strategically positioned fire crept through 24 acres of prairie fen and oak upland to control woody vegetation and stimulate sedge growth to encourage the butterflies to expand into newly burned areas. The burns appeared to have a great impact on habitat, and in weeks new shoots of sedges were popping up through the wetland soils - but did the Mitchell's satyrs approve of the work?

When this extreme habitat makeover became available to adult butterflies the following July, surveyors were ecstatic to not only count roughly 40 butterflies in the core population, but also to find wandering male and female butterflies in the flight corridor cut AND over 300 yards away in corners of the preserve where they hadn't been seen in the past four years.