Prairie Fen Series – Being a Prairie Fen Steward

Welcome to the final post in this series! In the first post, we discussed the unique geological processes that form prairie fens. Then in the second post, we presented plant species that we can use to discover prairie fen habitats. Lastly, we will be discussing the threats prairie fens face, what we are doing on-site, and why our efforts are so important.

My time at the parks has come to a close. Having arrived in the early spring and leaving in the early fall, I have witnessed lots of change. I followed the life stages of plants as they transitioned through the seasons. From emergence to bloom to death, I got to be a part of it all. Just as amazing, this was the first position where I was able to actually see the results of our stewardship efforts.

I personally have felt the most fulfillment from working at the prairie fen off the Paint Creek Trail. Oakland Township’s portion of this fen is only about a half-acre, but the larger fen habitat extends up and down Paint Creek. Even with its small size and history of fragmentation and disturbance, our little fen patch is resilient. We hope to restore our park’s prairie fens to their full biodiversity capacity.

Threats and restoration

Our Paint Creek Heritage Area – Fen can be used as a case study of the major threats these natural communities face. Our fen was once a part of a larger wetland complex extending to its south and west, but the connections to this wetland and the surrounding uplands have been damaged over time. Due to the parcel’s small size, there is little buffering it from encroaching development. The smaller a site, the more vulnerable it may be to changes in the surrounding landscape and threats. These threats mainly include a lack of fire, invasive species, nutrient pollution, and changes in hydrology.

Fire Suppression

Just like our oak lands and prairies, the suppression of fire on the landscape and the removal of indigenous land management practices have changed the composition of our prairie fen. The loss of fire has compacted the sedge meadow zone of the fen while increasing the woody zone (check out the previous post to learn more about fen vegetation zones).

Interestingly, the majority of our fire-dependent landscapes in Michigan that have held on after European colonization have been along railroads. In the late 19th century a railroad was built on what is now the Paint Creek Trail, cutting right through the fen. As mentioned in Cam Mannino’s previous blog post, fires sparked by passing trains spread into the surrounding landscape, maintaining natural communities like oak savanna, prairie, and prairie fen.

With the decommissioning of the railroad in the late 1970s, we now need prescribed fires to maintain the integrity of the prairie fen. We try to use controlled burns every 3-5 years to preserve the remnant prairie fen. The burns control invasive woody shrubs and remove dead stalks of Phragmites and invasive cattails after treatment. In addition, fire encourages plants to bloom more profusely and allows seeds of fen plants to germinate. The last controlled burn at the site occurred in 2019.

Invasive Species

Invasive species may proliferate due to problems, like fire suppression, nutrient pollution, or hydrology changes. Often, though, invasive species both exacerbate these problems and create new issues of their own. Both invasive cattails and Phragmites grow more vigorously in wetlands with lots of nutrients. The dense stands of Phragmites and cattail, and the thick layers of dead thatch that accumulate, crowd out fen plants. Invasive woody shrubs like glossy buckthorn and common buckthorn often invade fens that have dried out due to hydrology changes that result from building a trail, berm, or road through a fen, fo example. However, these invasive shrubs can also change conditions in a fen to facilitate their own invasion.

When our Paint Creek Heritage Area – Fen was acquired over a decade ago, large areas had already been encroached by invasive woody shrubs, narrow-leaved cattails, and Phragmites. We have prioritized saving the core area of our fen by controlling invasive Phragmites and cattails over the last five years. Fen plants like shrubby cinquefoil, Kalm’s lobelia, and grass-of-Parnassus are growing again in areas that used to be dense Phragmites or cattails.

Now we’re starting to work on the invasive shrubs that are spreading into the fen from the edges. In one area glossy buckthorn shaded out a nice Grass-of-Parnassus patch. This year the stewardship crew started clearing the glossy buckthorn so it may return.

Nutrient Pollution

Our fen-specialist plants are adapted to growing in alkaline, low-nutrient environments. Increased nutrient inputs from farm runoff, lawn fertilizer, leaky septic tanks, or deposited from the atmosphere through rainfall really change the function of a prairie fen by favoring more generalist wetland plants and invasive plants that can take advantage of increased nutrient levels. Left unchecked, Phragmites, invasive cattails, reed canary grass, and purple loosestrife that like high nutrient levels often grow in dense stands with no other plants, patches that we describe as “monocultures.”

A cattail monoculture at the Paint Creek Heritage Area – Fen before (L) and recently after (R) treatment.

We often can’t address past or ongoing nutrient pollution issues directly if they happen off our property, so try to limit the damage from high nutrient levels. The last three years the stewardship crew has been working at selectively treating narrow leaf cattail stands. To learn more about how this treatment is done, check out a past blog post. I have hailed it as being one of the most taxing yet most rewarding stewardship tasks. I know that each treatment causes the cattails to shrink away and reveal more prairie fen habitat.

Change in Hydrology

The steady supply of cold, calcium, and magnesium-rich water in fens really is their lifeblood. Unfortunately, many property owners don’t realize how special fens are and permanently damaged them by digging ponds. In addition to scooping up valuable fen, digging ponds lowers the water table by creating a low spot in the wetland where water can collect. This creates drier areas that become establishment hotspots for invasive species like glossy buckthorn and other invasive shrubs.

A wall of glossy buckthorn creeps into a fen, slowly shading out the unique wetland plants that this class visited to observe! This photo was taken in Bakertown Fen Preserve in SW Michigan by Grant Vander Laan.

Other changes can affect fen hydrology directly or indirectly. In the past, many fens were dried out by the installation of drain tiles and ditches to “improve” them for agriculture. Building roads, driveways, and trails disrupt the flow of water through a fen by acting like a dam, creating wetter conditions above and drier conditions below. Extracting water with wells for irrigation or other uses can also deplete aquifers that feed fens. It is critical that we partner with surrounding landowners to protect the water that charges the prairie fen.

Why Put In the Effort?

Although our fen is small, it has many high-quality specialist plant species present. Fen ecosystems also support a plethora of rare insect and animal species. In fact, several insect species rely entirely on prairie fen communities and would go extinct without them. You can check out the rare plants and animals associated with prairie fens at Michigan Natural Features Inventory (MNFI).

Prairie fens are globally rare wetlands that are rich in biodiversity. This photo is of our newly acquired prairie fen at Fox Nature Preserve. It is one of our higher-quality parcels.

With our fen off the Paint Creek Trail, it only becomes increasingly difficult to buffer it from the effects of habitat fragmentation. This is especially true for prairie fens, as they often blend into surrounding uplands, wetlands, and bodies of water. However, even in the face of fragmentation, species may be able to persist if they can move between small high-quality parcels. As you might imagine, this may be more difficult for a slow-moving species like a turtle than it is for a flying insect like a butterfly.

A restored prairie fen right next to the Paint Creek Trail is also an excellent educational opportunity for trail users. Since it is only half an acre, the site is manageable and able to show the significance of our stewardship work. As with any restoration project, it is imperative that objectives are well-defined. In the case of the Paint Creek Heritage Area, our team is working to maintain high-quality habitat that trail users may be able to see and learn from. With our invasive shrub removal efforts near the trail, we hope the prairie fen will become more visible to folks passing by. We also hope that other township residents and neighboring properties join us as prairie fen stewards. The more we protect the surrounding area, and the more we get people involved to protect our fen, the greater the impact of our little half acre will have.

Each Action Makes a Difference

Stewardship work is often laborious and ceaselessly repetitive. The blood, sweat, and tears our stewardship crew spent at the half-acre fen parcel have been rewarded time and again by our encounters with fen dwellers. Whether it is the noisy flush of a spooked woodcock or the silent presence of a butterfly, visits to the fen never felt lonesome. While treating our last group of narrow-leaf cattail for the season, fellow steward Cassie spotted a baby Blanding’s turtle. After she set the baby down, she turned to me and exclaimed how happy she was to have seen that turtle. We had been selectively hand-wicking cattails all morning. We were tired and hungry for lunch. But after releasing the prehistoric baby back into a pool of groundwater, we continued our tedious task with newfound ambition. Our work was making a difference.

Prairie Fen Series – Meet our Dynamic Peatland!

Take some time to learn about Southern Michigan’s most underrated ecosystem, the prairie fen! In this three-part series, we will go over what a prairie fen is, how to identify this community by its plant species, and what threats they face. This first post offers a reflection on these globally rare, but locally abundant, biological treasures by comparing them to their more well-known cousin, the bog. We will start the series by looking at the geological events that formed these unique wetlands using photos and stories from Michigan’s largest prairie fen. Stay tuned for two more posts all about our Township’s own prairie fen plant species and its history of being overlooked.

Peatlands: Bogs and Fens

Wetlands have received a lot of hype recently due to their capacity for preserving biodiversity and mitigating climate change. According to the International Peatland Society, the majority of our world’s freshwater wetlands are composed of peatlands. Most peatlands are classified as either fens or bogs. The saturated, anaerobic (no oxygen) soils of these special wetlands do not allow rapid decomposition of plant matter, allowing net accumulation of peat over time. As a result, peatlands are the largest terrestrial storage for carbon, according to the International Union for Conservation of Nature (IUCN).

Although both peatlands are adept at producing incredible biodiversity and carbon storage, they do not receive equal attention. I’ve noticed that even among my science-driven peers, fens are not as well-known as bogs. In undergrad, I was taught more about bogs than fens. Perhaps because bogs are more widely distributed and occur more frequently in Michigan. Or possibly because the highly acidic conditions (low pH) of bogs make them a more singular group, while the fens have several different subtypes. In college, I remember briefly learning that fen wetlands were fed by alkaline (higher pH) calcium and magnesium-rich groundwater, and bogs by rainwater.

Expanding my knowledge of the wondrous prairie fen

In Michigan, the fen group is made up of five natural communities, including prairie fen (check out coastal fen, northern fen, poor fen, and patterned fen if you’d like to learn about the other fens). Prairie fen is appropriately named since it shares many plants found in nearby tallgrass prairies. Prairie fen is found only in the Midwest, thanks to our mighty glaciers.

Map of lower Michigan’s glacier lobes in the most recent glaciation. The Wisconsin glaciation ended around 11,000 years ago. Image is taken from 2015 geomorphic study of the southern Lower Peninsula.

In Michigan, prairie fens primarily occur in the two interlobate regions of the southern Lower Peninsula. We have one interlobate region on the west side of the Lower Peninsula, and other interlobate region called the Jackson Interlobate here in the southeast region. These regions have a complex array of hills and valleys caused by the consolidation and withdrawal of glacier lobes during the Wisconsin glaciation. As noted earlier, all fens are fed by spring water. In the hilly landforms of the Jackson Interlobate, gravity pulls water down through the glacial deposits rich in calcium and magnesium. The alkaline water eventually flows down to the bases of slopes, showing up as spring-fed fens.

A figure displaying fen hydrology from Exploring the Prairie Fen Wetlands of Michigan by MNFI/Michigan State University Extension.

The calcium-rich, alkaline groundwater can be a tough environment for plants. A special set of plants that we call fen “indicator species” tolerate these harsh conditions better than general wetland plants. When we find these plants we know to look closer to see if the surrounding wetland is indeed a prairie fen. Tune into the next blog post in this series to learn more!

Map showing the distribution of prairie fens in Michigan. Circled in red is a cluster of fens that includes those in our township. The northwestern part of Oakland County is where Michigan’s largest prairie fen resides in Springfield Township. Figure from the 2009 Mitchell’s Satyr Habitat Conservation Plan.

My First Fen Visit

No amount of diagrams and reading can prepare someone for what a natural community is like until you are standing in one. I finally had the chance to experience a Michigan fen during the Eastern Massassauga Survey our crew helped with earlier this summer. The survey took place in Michigan’s largest remaining prairie fen in Springfield Township! On the drive there, my unconscious bias predicted the habitat to look similarly isolated and alien as an acidic bog.

I could not have been more naïve. In stark contrast, the landscape was alive and coherent. As I stood unstably on sedge mounds, I could hear what sounded like the thirsty noise of draining a bath. Only in the plants parted could I see where the peculiar sounds were coming from. Calcareous spring water, cold from being locked in the dark earth, ran in rivulets beneath us as we walked. There were also areas where streams flowed on top and through the vegetation. Water and earth weaved in and out of each other; I quickly realized that fens are interlaced with the rest of our sculpted landscape.

This picture depicts the seamless progression from prairie fen to oak forest.

Unlike bogs, which similarly occur in depressions caused by melted glacier ice, prairie fens are not isolated pockets of water. These fens are often part of larger wetland complexes, often occurring on the edges of lakes or along streams. Prairie fen’s plant communities often also morph into surrounding environments like oak barrens and openings, even sharing the same historical need for fire disturbance.

Leaving Springfield’s fen, I rejoiced in the never-ending surprises that come with being a student of the natural world. I had no idea a peatland could feel so energetic. I had been under the impression that all peatlands were as dead as their layers of preserved organic matter.

The next post in this series will dive deeper into the dynamic life that these fens sustain using flora and fauna snapshots from our prairie fen along the paint creek trail. In the meantime, you can check out a previous blog about the Unique Wetland Communities Along the Paint Creek Trail to get some background on the work we do there.