One of the world’s rarest butterflies, with fewer than one hundred remaining in the wild at recent surveys, resides right here in the prairie fens of southern lower Michigan. The tiny Poweshiek skipperling butterfly was once one of the most abundant butterflies in the Midwest, but habitat degradation and loss have resulted in the near extinction of this species throughout its range.
Conservation biologists have been working in recent years to recover the butterfly and its habitat—as detailed in MNA’s recent “Life on the Brink” mini-documentary—with assistance and funding from the U.S. Fish and Wildlife Service. The plight of the Poweshiek skipperling butterfly, however, extends beyond the borders of the state and is evidence of a greater ecological problem that affects many other species.
Unlike the distinctive orange and black markings of monarch butterflies, Poweshiek skipperling butterflies are small and brown, with few distinguishing features. The Poweshiek skipperling can be easily mistaken for one of their more common skipper counterparts like the European skipperling. Their small size also means that they are more likely to be stepped on than spotted, which presents a challenge for researchers who would like to raise awareness of the butterflies while simultaneously protecting their habitat from over-visitation.
The Poweshiek skipperling butterfly however is a symbol for the overall phenomenon of insect decline, not just in Michigan. Insects being the most abundant living creatures on earth, their decline and particularly a general lack of understanding of the cause of that decline is certainly reason to be concerned.
Fortunately, organizations like the Michigan Nature Association work to protect habitat for these species and participate in conservation efforts like those of the Poweshiek Skipperling International Partnership, all of which is guided and often funded by federal agencies like the U.S. Fish and Wildlife Service through the Endangered Species Act.
In southern Lower Michigan, the populated landscapes of farms, homes, and towns create predictable, right-angle patterns of human settlement when viewed from above. But winding across and through those straight-line grids, meandering corridors trace the paths of streams and rivers.
These corridors often harbor something really important, a dynamic natural community known as a floodplain forest. Floodplain forests are a vital part of Michigan’s natural heritage. Periodic flooding, scouring, erosion and sediment deposition follow the rise and fall of water levels creating diverse microhabitats that are used by a variety of wildlife.
Land meets water in a floodplain forest. When that stream or river tops its banks, it reshapes the bottom lands with tree falls, migrating river channels, new sediment deposits or erosional scour. These actions create fluvial landforms such as natural levees, backswamps, oxbow ponds, and terraces – all associated with a particular type of vegetation.
The flowing waters help the soils thaw earlier in the spring, meaning these are often the places where the first wildflowers bloom. Insects, invertebrates, reptiles, and amphibians appear almost simultaneously to take advantage of the food sources provided by these wildflowers. “These forests are often very important stopover or even nesting sites for declining neotropical migratory birds as well.” “Often they are the last forested strongholds in a lot of agriculturally-dominated landscapes and are therefore valuable for a variety of plants and animals.”
Threats to these impressive habitats are an all too familiar list – invasive plants and animals, hydrological modifications (levees, impoundments, channelization, dams), including those brought by climate change, habitat loss due to industrial, residential and agricultural fragmentation, and incompatible timber management. For those reasons, floodplain forests are both globally and state-ranked as vulnerable.
For sometimes being no more than a narrow, green edge along a river, the magnitude of floodplain forest benefits outweigh their seemingly limited size. Besides important habitat, they play a critical function in Michigan’s fight against climate change. When water flows across the land to a river, the floodplain forest serves as a buffer, absorbing both the quantity and the energy of that flow while filtering pollutants. Floodplain forests therefore help to protect the water quality in many of Michigan’s watersheds.
If you’ve spent much time in Michigan, you are likely familiar with the excitement that comes with spring—wildflowers blooming, birds migrating, trees budding. It is a time of renewal and rebirth as the drab browns of winter slowly return to green, the additional sunlight and longer days allowing the process of photosynthesis to recur.
Perhaps the most exciting of all are the ephemerals—the short-lived plants—like spring beauty, trillium, hepatica, and more that provide important food sources for pollinators. These temporary wonders are among the first to appear on the forest floor, anytime between March and June depending on the latitude and elevation. As insects emerge from under leaves where they’ve spent the winter they must go in search of food sources like nectar from these spring ephemeral wildflowers. Widespread and abundant ones like trillium are an easy source for many insects (and birds in search of an insect meal), but there are also some insects that are more particular about the plants they seek nectar from.
It is well-known that monarch butterflies need milkweed for the caterpillar stage of life. Milkweed is actually a toxic plant containing glycosides that would normally make them inedible to people and wildlife, but monarchs have developed a tolerance for this toxin that offers them protective benefits. Birds that eat monarch caterpillars will become sick due to the stored glycosides, and so they learn that the color pattern associated with the monarchs are not a source of food, and will move on.
Another ephemeral plant that blooms later in the summer—the Black-eyed Susan—has a less well-known benefit to Michigan’s federally endangered Poweshiek skipperling butterfly. Adult Poweshiek skipperlings feed exclusively on the nectar of Black-eyed Susan flowers, making these common wildflowers an essential part of the recovery effort for this butterfly.
So, as signs of spring make their way across Michigan and you delight in the sight of wildflowers blooming, it is a good reminder that these brief encounters are just one of the many important parts of a healthy ecosystem.
Several MNA nature sanctuaries are well-known for their wildflower displays. Dowagiac Woods Nature Sanctuary in Cass County is home to a wide variety of wildflowers including trillium, trout lily, dutchman’s breeches, and many more. Trillium Ravine Plant Preserve in Berrien County holds several different types of trillium that carpet the forest floor for an incredible display for trillium seekers. Visit michigannature.org to plan your next visit today!
Michigan is well-known as the “Great Lakes State” but there is much more to the state’s freshwater ecosystem than the massive inland freshwater seas that garner all the attention. There is a true “underdog” in Michigan’s freshwater systems—groundwater.
In honor of National Groundwater Awareness Week (March 5-11, 2023), the Michigan Nature Association is proud to explore a vital component of Michigan’s groundwater system, fens, written by MNA volunteer Zoë Goodrow.
What is a fen?
When the final glaciers in Michigan retreated north about 8,000-12,000 years ago, they shaped landforms that eventually became the wetlands we see today. Fens are among the rarest types of wetlands – more specifically, peatlands – found in Michigan. What differentiates fens from other wetlands is their hydrology.
Fens are fed by a continuous flow of groundwater that filters through nutrient-rich layers of sediment, like limestone, resulting in an ecosystem rich in calcium and magnesium. The steady supply of groundwater into fens means that fen soils remain saturated throughout the year. This causes a reduced abundance of bacteria that break down plant materials (compared to other wetlands), resulting in a buildup of decayed plant debris – also known as peat.
Rare species in fens
Fens have 500 times more rare plant and animal species than the average acre of land in Michigan. They support nearly 60 rare species and are the Michigan equivalent of rainforests in terms of relative biodiversity. Typical plant species that are unique to fens across Michigan include sphagnum mosses, white lady slipper, fringed gentian, edible valerian, and carnivorous plants including sundews and pitcher plants. Rare animals that habituate fens include the yellow rail, Mitchell’s satyr, and eastern massasauga rattlesnake. Fens are extremely fragile and sensitive systems that are already being impacted by climate change, which does not bode well for the rare species that are endemic to fen ecosystems. Because of this, and their significance to Michigan’s biodiversity, it is important to know the guidelines for minimizing disturbance before you visit one.
Types of Michigan fens
Michigan is home to many types of fens, including the northern, prairie, patterned, and coastal fens. These different fens are characterized by the natural processes that formed them and the climatic conditions of the regions they reside in.
Northern fens are found in the Upper Peninsula and the northern half of the Lower Peninsula. They occur where a glacial outwash meets a more textured glacial feature like a kettle lake or an end moraine.
Prairie fens, located in the southern half of the Lower Peninsula, occur in former oak-savanna prairies. As their name suggests, they are dominated by a mix of prairie and wetland sedges, grasses, and forbs. These fens were formed via the same glacial processes as northern fens.
Patterned fens, also known as string bogs, also occur in the Upper Peninsula. What differentiates these fens from northern fens is that they are a series of alternating ridges and hollows, oriented parallel to the contours of the land. The natural processes responsible for forming these unique systems are still unknown. While there are several proposed hypotheses – researchers agree that an essential factor is the direction of water movement, as the ridges and hollows are consistently oriented perpendicular to the flow of groundwater. (See more on patterned fens with MNA’s Fox River Wetlands in the video linked below)
Coastal fens occur along Lake Michigan and Lake Huron in the Upper Peninsula and northern Lower Peninsula. The natural processes that formed them are inextricably linked to those of the Great Lakes. The water tables that influence these systems are subjected to seasonal and multi-year lake level fluctuations, so vegetation in coastal fens changes quickly when water levels change.
To experience a fen habitat first-hand, consider visiting MNA’s Lefglen Nature Sanctuary in Jackson County. The sanctuary is home to a prairie fen and a natural flowing well visible from the south trail. Visit our online sanctuary map for directions and more information.