Michigan Nature Monday – Spring Ephemerals

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.

False rue anemone and spring beauty in bloom at MNA’s Dowagiac Woods Nature Sanctuary. Photo by Lauren Ross.

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.

Poweshiek skipperling butterfly on a black-eyed Susan. Photo by Kelly Nail, USFWS.

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.

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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 Nature Monday: Michigan’s Many Water Resources

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.

Prairie fen photo by Dave Cuthrell.

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)

Click on the image above to watch “The Fox and the Fen”. Photo by Jason Whalen, Fauna Creative.

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.

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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.

Michigan Nature Monday: Dunes

Snow blankets much of Michigan now, which may have you dreaming of summer vacations to the beach, and for good reason – Michigan has plenty to choose from! But sandy shores and their hilly companions—dunes—support more than just a retreat from the daily grind.

Vegetation grows on a dune. Photo by Andrew Bacon.

Dunes in Michigan are unique because, unlike their desert counterparts, they are impacted greatly by the water of the Great Lakes. Fluctuating lake levels contribute to dune formation by stabilizing the dunes with increased water levels as well as increased wave action in high years. These impacts are usually so slow-moving that they go unnoticed, but recent erosion along Lake Michigan due to increased lake levels had the dramatic effect of damaging some houses built close to the edges of these dunes.

One distinguishing characteristic of Michigan’s dunes is the amount of vegetation that can be found on them. There is a limited supply of sand in the Great Lakes being deposited on the dunes. This in time allows for various grasses and trees to take root and grow, further slowing or stopping the movement of the sand and allowing for more vegetation to grow. These plants are therefore critical to preventing erosion and dune migration.

Several rare plant types are supported by these dune habitats including Pitcher’s thistle, Houghton’s goldenrod, and Lake Huron tansy, just to name a few. At MNA’s Lake Huron Sand Dunes Plant Preserve in Chippewa County, a unique natural community known as a “wooded dune and swale complex” exists as a series of sandy ridges and low, swampy areas that were formed in multiple stages as lake levels receded around 12,000 years ago.

Lake Huron tansy. Photo courtesy Peggy & Jerry Keeney.

As with many natural communities throughout Michigan, a major threat to the health of this sanctuary is the impact of invasive species. Particularly at Lake Huron Sand Dunes Plant Preserve, invaders such as Spotted knapweed and European Marsh thistle are aided by habitat disturbance. MNA monitors the sanctuary regularly for signs of disturbance and works to remove invasive species before they become too widespread.

So as you plan your next Michigan beach vacation, remember that the sand is part of a much larger and ever-changing habitat complex.

Michigan Nature Monday: Poweshiek skipperling

One of the rarest butterflies, the Poweshiek skipperling, is truly on the brink of extinction. Once abundant in the tall prairie grasslands and the prairie fens of several states and provinces in the upper Midwest, the tiny butterfly is now found only in a handful of sites in Manitoba and northern Oakland County, including an MNA nature sanctuary. Loss of habitat and other factors contributed to a decades-long—and now a relatively recent and rapid—population decline that has scientists scratching their heads and worried about what their disappearance may mean for other pollinators.

The globally endangered Poweshiek is now so rare that only 100 individual butterflies were counted in a 2021 census. Recovery plans—aided by an international partnership that includes MNA—call for captive breeding efforts to headstart individuals and increase survival to adulthood in order to build a reserve population that can be reintroduced to the wild. The Minnesota Zoo, John Ball Zoo in Grand Rapids, Michigan State University’s Haddad Lab, and the Michigan Nature Association are specifically collaborating within the Poweshiek Skipperling International Partnership to annually produce more individuals for wild releases in 2022 and beyond in what is known as ex situ or “offsite” conservation.

Poweshiek skipperling photo by Cale Nordmeyer, Minnesota Zoo

MNA is proud to protect habitat critical for the Poweshiek skipperling’s survival, and to be part of the important partnership that is working to save this species from extinction. We look forward to continuing participation in this partnership effort to increase the Poweshiek skipperling population in the wild in the coming years.

Learn more about our conservation work and how you can contribute at michigannature.org.