It often happens that shortly after I publish a blog about a particular park, something interesting pops up there that I wish I could have included.
So to solve that issue, Dr. Ben VanderWeide, Oakland Township’s Stewardship Manager and I decided that it might be fun to slip in a short piece, a “field note,” now and then about these intriguing and/or surprising discoveries. And wouldn’t you know, one cropped up last week!
A Young Blue Heron Discovers a New Challenge: Ice!
Readers may remember that in the recent Bear Creek Nature Park blog, my photographer friend Paul Birtwhistle introduced us to a voracious juvenile Great Blue Heron (Ardea herodias) who for weeks spent its mornings snapping up green frogs and fish from the drought-depleted Center Pond at Bear Creek.
Well, after one frigid night last week, the pond froze with a thin sheet of ice. And of course, the Heron returned in the morning to continue its feast. But to its apparent dismay, the water had changed drastically since the day before. The heron stepped out cautiously on this oddly slick surface and looked about. In the short video below, you’ll hear that Paul was amazed at what he was filming. And the young Heron was just as surprised at finding the pond surface inaccessible after weeks of dipping into it to find a rich trove of food. [Note: Vimeo, which formats our videos, attributes everything on Ben’s Vimeo account to Ben. But this week, all of the photos and videos were generously shared with us by Paul Birtwhistle.]
This youngster didn’t give up easily! It stared at the surface repeatedly. Paul guessed that he was seeing movement under the thin ice.
I wonder if perhaps the juvenile thought something was wrong with its eyesight, as it tried to bend down and get closer to the ice. Or perhaps it still thought it could snag its prey if it crouched down a bit…
Hmmm…maybe I just need to get a little bit closer.That usually works. No? Drat! Photo by Paul Birtwhistle
The heron tread verrrry cautiously on the thin, icy surface but – Yikes! Suddenly its feet slipped from under it and up went those dramatic wings to help it find its balance.
Whoops! Wings up! What’s the deal with this weird pond? Photo by Paul Birtwhistle
Trying to keep its hopes up, the bird spent about a half hour stepping carefully on the slippery surface and peering down at the ice-blurred surface of the pond. The youngster appears to warm one foot by bringing it to its feathers – or maybe it’s simply scratching an itch. In any case, this young bird looks pretty frustrated at this puzzling new experience.
After more than a half hour of exploration, the young heron took flight. Let’s hope it found its way to deeper water and the society of older herons who would show this young ‘un how to fish from the icy edge of open water.
Paul was surprised and delighted to see a heron on ice! And so was I when I received his photos! We thought Great Blue Herons would already have migrated. But when I contacted experienced naturalist and bird bander, Allen Chartier, he explained that, in his experience, though many migrate further, some herons just keep moving south to find open water. He sees them where warm water thaws the ice near power plants, for example. He believes most of them depart by January when even large bodies of water freeze over. Cornell University’s subscription website, Birds of the World, indicates that those mighty wings carry many of them as far south as the Caribbean. So bon voyage to our young puzzled friend. Hope you found a belly-full of food before nightfall!
Meanwhile, Nearby, More Experienced Neighbors Also Coped with the Icy Pond
Muskrats (Ondatra zibethicus) have created a “push-up” or lodge on the Center Pond this year, probably because Bear Creek marsh, where they more often spend the winter, has less open water than usual. Muskrats spend the winter mostly under water. Their metabolism drops and they efficiently utilize oxygen stored in their muscles. They slowly swim about, foraging for aquatic plants, though their diet can also include frogs, snails, small fish, occasionally even small turtles – if any remained after our hungry young heron departed! Since muskrats are mammals, however, they need to come up for air. Their push-ups have a platform inside where they can enter from underwater and then eat and rest comfortably in the air. Nice arrangement, eh?
The first time Paul noticed a muskrat, it was near the heron, gnawing its way through the thin ice to keep its channels open. In the photo below, note the ice being pushed up onto the muskrat’s muzzle as it acts like an icebreaker. Its long fur helps keep it warm and it can close its ears when under water. But as you’ll hear Paul say in the video, “It looks ever so cold!”
The next morning two muskrats fed at the pond. The first one in the short video below seems to be eating frozen plant material pulled up from the shallow water. Watch ’til the end of the video to see the second muskrat emerge from the push-up, gnaw on some ice and then decide to make a beeline underwater toward the first one – probably its mate.
It turns out that this affectionate pair is sharing its home with 3-4 other muskrats that Paul saw a few days later. They may be a family, though muskrats are known to hole up with unrelated muskrats in the winter. I suppose that more muskrats inside means more warmth. But the shallow water and the depleted amount of prey may turn out to be a challenge to these animals this winter. Drought like we’ve had lately can be a hazard to semi-aquatic animals. It’s much easier for predators like foxes and coyotes to reach the muskrats if the shallow water freezes solid.
Amazingly enough, a savvy potential predator did indeed show up on Paul’s next visit – an American mink (Neogale vison)! I’ve been hiking Bear Creek Nature Park for many years and never seen one there. But late one morning, this powerful, beautiful animal appeared on the north bank of the pond right behind the muskrats’ push up. Hmmm…. Various sources report that though minks eat several different small mammals, their favorite food is, you guessed it, muskrat! Well, winter’s a challenging time and the mink may have a mate to feed as well since minks breed during the winter. Everyone has to eat, right? Look at the magnificent specimen Paul saw! Its size, white chin patch and small white chest spot are good field marks for this impressive creature.
What a drama played out at the Center Pond this November! Will the young heron learn quickly how to find food on an icy morning? Will the muskrats find enough prey in the shallow water after the heron’s weeks of feeding? Will they successfully fend off the hungry mink or will this elegant, potentially lethal predator find a meal for itself at the pond? We’ll probably never know the conclusion to this series of events. But thanks to Paul, you and I had front row seats for this adventure in three acts, each featuring a creature coping with the vicissitudes of the season.
The Center Pond at Bear Creek Nature Park was a hub of avian activity during early fall. After a very dry summer, the water level fell significantly, exposing the muddy bottom in some areas and bringing underwater prey closer to the surface. And the birds came! Summer visitors who raised young here and birds migrating south clearly saw the remaining open water and muddy edges as an oasis. After the vernal pools dried up and even Bear Creek marsh filled with plants in the dry summer heat, the Center Pond provided an ideal place to find food!
I, sadly, wasn’t able to use my long lens much for birds in the last few weeks after a minor fiasco with my back – but never fear!
Two of my brilliant photographer friends, Bob Bonin and Paul Birtwhistle, generously filled my inbox with glorious shots of all kinds of birds they saw there! Through their eyes, you and I can witness what Bear Creek had to offer our avian friends in early fall. And I’ll add in a few extras from my October trips through Bear Creek’s fields and its oak-hickory forest. So let’s head out together on another virtual hike, this time with two other nature-loving photographers.
Off Toward the Slopes of the Western Meadow
The gardens near the parking lot on Snell Road are shedding their seed now. They currently look a bit chaotic, but all those seed heads will be a nourishing boon to birds this winter. But one hardy species, Cut-leaf Coneflower (Rudbeckia laciniata), contributed its bright yellow rays to the fall colors until mid-October. What a heartening native addition to a late-summer/fall garden!
Paul Birtwhistle and I both stopped by the Playground Pond this fall. In September, Paul came across a female Pileated Woodpecker (Dryocopus pileatus) banging away on one of the many snags (standing dead trees) in the pond. (Females have a black “mustache”; males have a red one.) At this time of year, she was probably seeking out wood-boring beetle larvae, though in general, carpenter ants are her preference.
When I arrived at the Playground Pond in October with the Wednesday morning birding group, a gang of juvenile Cedar Waxwings (Bombycilla cedrorum) were socializing in a dead tree. The juveniles are much less colorful than their parents – mostly gray instead of cedar brown and lemon yellow – but even at a distance, we could see the bright yellow tips on their tails and their developing black masks. (Click on photos to enlarge.)
In September, Paul ventured further west to the steeply sloping path of the western meadow where tiny migrators foraged at the edge of the woods. And what a group of golden beauties! The Magnolia Warbler (Setophaga magnolia) nests in conifers at the tip of Michigan’s “mitten,” the Upper Peninsula or in Canada. This female or immature male with its complete white eye ring, vivid yellow breast and gray head stopped by Bear Creek to rest and feed on its way to bask in Caribbean sun for the winter.
Another migrator, the Nashville Warbler (Leiothlypis ruficapilla), also breeds in “up north” Michigan and in Canada. It drops by in fall and spring when it’s migrating to and from its wintering grounds in Mexico. That’s quite a trip twice a year! Paul caught it pausing as it too sought out Bear Creek’s rich supply of insects for its long journey.
The other little bird Paul glimpsed in the west of the park was an immature male Common Yellow-throat (Geothlypis trichas). (Adult males have a white-banded black mask, and in immature males this mask is very faint; females have a warm brown head, yellow undersides, and olive back.) This young male might have hatched from an egg right at Bear Creek Nature Park since Paul and I repeatedly saw Yellowthroats or heard their “witchedy, witchedy” call near the marsh this summer. Or perhaps this one arrived from further north. In either case, he too stocked up on insects here before winging off to the southeast toward Florida or the Caribbean.
Strolling Along the Walnut Lane
The Walnut Lane which runs between two meadows serves as a favorite perusing perch for birds. When Paul arrived there on October 1, he spotted migrating Palm Warblers (Setophaga palmarum) gazing out among the golden leaves along the trail. After raising young in the Upper Peninsula or even Canada’s boreal forests, these striking birds stop by each fall on their way to Florida or the Caribbean to partake of our parks’ bounty.
The same day, down near north end of the Lane, Paul spotted a Chinese Praying Mantis (Tenodera sinensis). We have two species of non-native Mantises in Michigan. This larger one, at 3-5 inches, is a highly successful predator also on the hunt for insects. Its orange back with green edges is distinctive, though sometimes Chinese Mantises are solid green like the smaller species, the European Mantis (Mantis religiosa), which is no more than 3 inches long. These two may have out-competed the only native mantis in our country, the Carolina mantis (Stagmomantis carolina) which now exists only in the southeast. This one clearly focused on Paul. Maybe she was flirting?
In the late summer and fall, Eastern Bluebirds (Sialia sialis) frequently perch on the Walnut Lane. I saw a pensive female there on October 2. On October 5, Paul and I both saw a pair exploring the possibilities of a snag for insects now or perhaps next year’s cavity nest. In fact, the Lane area was full of their fluttering that day! The nesting boxes placed by the stewardship crew and tended by volunteers have added a lot of bluebirds to Bear Creek – and other parks with boxes – so keep an eye out for them!
A Ruby-Crowned Kinglet (Regulus calendula) also flitted about within the branches along the Lane. Paul caught this tiny bird between dashes from limb to limb (left below), while I just caught the blur of another one’s flight during the bird walk.
The Center Pond Feeding the Multitudes – and a Rare Visitor
Both of my photographer friends hung out at the Center Pond, a hub of activity in the fall at Bear Creek Nature Park. On each of his visits, Paul Birtwhistle snapped his photos quickly to catch in action two large, very successful foragers. In early September, he came upon a very excited Green Heron (Butorides virescens) with a crest that literally stood on end like a “punk” hairstyle. Maybe just the thought of all those “easy pickings” in the shallow water had a huge effect on this skillful fisher! Here’s a brief slideshow of Paul’s shots of its hunting techniques.
Paul watched a Great Blue Heron (Ardea herodias) feed day after day at the Center Pond. The first time, on October 9, he witnessed one snagging two different prey. Its first prize was a little Largemouth Bass (Micropterus salmoides)! Some flying bird must have dropped Bass eggs into the pond earlier in the summer since this pond is spring-fed. Each prey caught, Paul reports, was dipped in the water and then shaken vigorously. Cornell University’s website explains that this process may quickly break the spine before the heron swallows it whole. Gulp!
Its second catch was a small Green Frog (Rana clamitans). The heron came back the next day for another frog. In fact, Paul’s seen a heron fishing repeatedly for two weeks! Evidently, the shallower water after the summer drought made fishing much more profitable for the water birds this year! The pond may have fewer frogs next summer but we’re sending well-fed herons south during the migration. Here’s a small sampling of Paul’s amazing photos of this impressive bird, with its 6 to 7 foot wingspan and its skillful fishing.
The Wood Ducks (Aix sponsa) have also been bottoms-up feeding at the Center Pond during October. Paul got a wonderful shot of a pair surveying the pond from the edge. They’re probably here for a variety of aquatic plants, including the bright green Duckweed (aptly named!) (Lemna minor) and Common Water Meal (Wolffia columbiana) that they scoop up with their bills when they’re cruising along.
Male Mallards (Anas platyrhynchos) molt into eclipse plumage in later summer/early fall that makes them look more like the females. Later in the fall, they molt again into their breeding colors in order to attract a mate for the next season. I think this male, with its head bejeweled with water droplets, has excellent mating prospects! What a glamor shot! Thanks, Paul!
Of course, not all the foraging was going on in the water at the Center Pond. An unusual migrator appeared at the Wednesday bird walk. A Rusty Blackbird (Euphagus carolinus) settled down on the muddy shoals exposed by the drought and spent several hours flipping over leaves to see what insects, seeds or fallen fruit might be hiding there. My other patient photographer buddy, Bob Bonin, stayed at the pond for hours and caught his beautiful shot (below left). Rusty Blackbirds only pass through during fall and spring migration and their numbers are rapidly declining. I last saw them in 2015 when a small flock in their breeding colors (below right) landed in a wetland near the Center Pond. Researchers think their decline is caused by the usual suspects – agriculture, logging, development, soil contamination. So I’m glad our parks provided a rich source of sustenance for even this single Rusty in its fall plumage.
Bob’s patience paid off again. In those extra hours, he also tracked the quick, short flights of a variety of small migrating birds foraging at the Center Pond. Yellow-rumped Warblers (Setophaga coronata) eat a wide variety of foods during migration – insects when they can find them, seeds, berries of all kinds, including poison ivy berries! The field mark to look for, winter or spring, is the bright yellow patch between the wings on the top of its rump, though their plumage is much more dramatic in the spring, like most birds.
White-throated Sparrows (Zonotrichia albicollis) can be seen under my feeder during the fall and winter – maybe yours too? These hardy sparrows flooded into Bear Creek Nature Park early in October after breeding farther north. Their striped heads can sometimes be confused with the White-crowned Sparrow, but the White Throats have that nifty white patch under the beak and bright yellow spots (called “lores”) just above their eyes. Check out the pattern differences when you see a “little brown bird” pecking in the grass! It’s not “just a sparrow!” Try thinking “Which sparrow is it?” Thanks to Bob for this great identification shot!
Down on the dock, the birding group saw an Eastern Phoebe (Sayornis phoebe) doing what flycatchers do best – quickly sallying out over water to snitch insects from the air. These grayish-brown songbirds sing a steeply descending “Pheeee-buzz” song in the summer and are easily identified by an almost continuous pumping or twitching of their tails when perched.
A Short Walk Through Alice’s Woods, aka the Oak-Hickory Forest
Let’s wind up our virtual hike with a quick walk through the oak-hickory forest, which is now named “Alice’s Woods,” in honor of the incredible Alice Tomboulian who inspired, helped found and served Oakland Township Parks for so many years. Alice was an intrepid lover of the natural world who understood the importance of both preservation and the urgent requirements of restoring that land with native species. She was an inspiration to so many, including me, and is greatly missed.
The quiet of a forest always soothes me, and that’s especially true in autumn light. Fewer birds, other than woodpeckers, regularly appear for me in the woods. I come across Titmice, a summer Wood-Pewee, once a Sharp-shinned Hawk, the occasional migrating warbler, the Brown Creeper and two or three times a Great Horned Owl, among others. But this October, I felt surrounded only by what I call “leaf talk.” The spinning descent of dry leaves accompanied the tree shadows slipping across my husband’s shoulders in the dappled light. In the woods, we tried to notice the small forest details that tend to show themselves when we aren’t peering up into the canopy for birds.
First, we came across an array of fallen logs, each one heavily filigreed with Turkey-tail Mushrooms (Trametes versicolor). These polypore mushrooms help break down dead wood into sugars and carbon dioxide by loosening the bonds of lignin that made the wood and bark rigid. In other words, these fungi are gradual wood recyclers – and they’re beautiful while doing it!
The concentric geometry of a web spun by an Orb-weaver Spider (genus Araneus) caught our eye in a spot of fall sunlight. The spider may have expired on a chilly night, but she left behind evidence of her skill. According to Dr. Gary Parsons at Michigan State University’s Bug House, the mating process in this genus can be a bit fraught. “Males …usually need to perform some kind of species-specific signal (usually by plucking the web in a specific pattern) as they approach the female to let them know they are not prey and wish to mate. If the female is overly hungry or not ready to mate, she might turn on the male and eat him if he gets too close. If she is ready to mate, she probably will leave him alone during the act, after which the male beats a hasty retreat.” Don’t mess with an unwilling female Orb-weaver!
Emerging from the woods to head back to the car, we were greeted by the charmingly bug-eyed Spotted Spreadwing damselfly (Lestes congener). This little creature survives longer than most other damselflies, into October and even November. Its eggs overwinter and can tolerate temperatures as low as -17 degrees, according to my cherished guide, Damselflies of Minnesota, Wisconsin and Michigan by Robert Dubois and Mike Reese. So glad this hardy little insect posed for me.
Red-legged Grasshoppers (Melanoplus femurrubrum) accompanied us along every path, springing away under our feet. In our colder latitudes, these grasshoppers are smaller and have to mature more quickly since this species only reproduces once in a season. Females will lay eggs in the soil to overwinter. The nymphs will dig their way out next spring and molt 5-7 times before being ready to mate.
I hope you’ve noticed the sweet, buzzing song of crickets – and probably some katydids and grasshoppers too – this time of year. My sharp-eyed husband spotted one of the tiny Ground Crickets (family Trigonidiidae) whose males sing so wonderfully this time of year just by pulling the scraper-like edge of one forewing against the other. Dr. Parsons would have needed to have this tiny (maybe 3/4 inch?) creature in hand to identify it among the seven species in three genera in Michigan. He did tell me that they can survive quite cold temperatures down in the grass as long as they don’t freeze. So when the weather warms back up in the fall, the males “sing” again, hoping to mate before winter sets in.
Ensuring Autumn’s Richness Continues to Feed the Future
I like to think of autumn as a time of rich harvest in our parks. Yes, it’s true that the leaves are falling and flowers and grasses are withering – but that means seeds can feed hungry migrators before they fly further south on a north wind under the stars. Those dry seed heads in our parks, or left for the winter (we hope) in your drying garden, can nourish our avian neighbors who tough out the winter with us. Insects have left behind chrysalises, cocoons, and galls, where their young will gradually transform next spring into dancing butterflies, fluttering moths in a summer night, and the millions of caterpillars and adult insects needed to feed next summer’s frogs, flycatchers, soaring swallows and thousands of baby birds. It means seeds and nuts will rest on or in the cooling earth, ready to crack open and thrust out new life when the soil warms again. While we humans sip our sweet cider and bite into crisp apples, nature is serving up food for the multitudes and sowing new life in its endless cycle of abundance.
If we continue to preserve natural areas and restore them to the health that nature designed through millennia, we can hope that endless fruitful autumns stretch ahead on our planet home. Here in Oakland Township, we’re doing our best to do just that in our parks. It isn’t enough to simply preserve open land, as crucial as that is. Through the yearly cycles of restoration work performed by our stewardship crew and volunteers under Dr. VanderWeide’s expert guidance, we are continuously caring for the land. We are slowly restoring as much of its historic diversity, richness and beauty as we possibly can after years of human use or neglect. And that transformation, that commitment to nurturing the land, sustains my commitment to the future, to a healthier world for the young, even when the nights grow longer and bare trees sketch black tracery against the autumn sky. I hope it does that for you, too.
Stewardship Manager Dr. Ben VanderWeide and volunteers gathering native seed to enrich other township parks.
I can’t believe I already have to write this goodbye post; it seems like just yesterday this crew was starting out, learning what it takes to be a well-oiled habitat restoration machine. Like previous years, our natural areas stewardship team has picked and sprayed its waythrough garlic mustard, crown vetch, swallow-wort, a multitude of invasive shrubs, bittersweet, and Phragmites. To top it all off each person has written several amazing blog posts about topics like golden oyster mushrooms, Blanding’s turtles, cow parsnip, and fens. We were able to accomplish so much this summer. Without their help the parks wouldn’t look as good as they do now!
Cassie returned to Northern Michigan University where she is pursuing her bachelor’s degree in fisheries and wildlife management. Emma returned to Ohio University to continue her bachelor’s degree in field ecology with a certification in environmental studies. Finally, Camryn is exploring opportunities to continue her career in the field of ecology.
Their curiosity, infectious positivity, and love of nature were greatly appreciated this summer! The effects that they have had on our parks will be seen for years to come. We wish them the best of luck in their next endeavors. We will miss you guys!
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 inhydrology.
Just like our oak lands and prairies, thesuppression 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 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.
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.”
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.
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).
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 thePaint 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.
Welcome back to our prairie fen series! The first post took a broad look at what prairie fens are and why they exist. In this post, we will focus on key plants that act as indicator species for a prairie fen community. Using mostly pictures taken from our township’s own fens, we will also dive into the vegetation zones that characterize these unique habitats.
I have been fortunate enough to visit each prairie fen in our township parks. I am always amazed by the diversity of plants I find at each of these sites. I started this series because I had little knowledge of what a prairie fen was, and no idea that I lived among them. Unlike other wetlands, I found that prairie fens blend extremely well into the surrounding environment. Maybe this is why I and so many others were estranged from these fen communities that are my close neighbors here in southern Michigan! A fen could be right under your nose in your local natural area or even your backyard! I hope this post may guide you if you hope to get acquainted with the wondrous prairie fen.
Our prairie fens
We have prairie fen habitat in three of our township parks: Draper Twin Lake Park, Paint Creek Heritage Area – Fen, and Fox Nature Preserve. The plants that have greeted me at these prairie fens ranged from recognizable prairie and wetland species to more specialized flora able to survive in difficult environments. With their unique conditions, prairie fens are biodiversity hotspots for plants, animals, and insects in Michigan.
As the book Exploring the Prairie Fen Wetlands of Michigan states, prairie fens typically support twice the plant species found in bogs. Although both fens and bogs exhibit difficult growing conditions, with pH ranges in the extremes, fens exhibit a wider diversity of vegetation types. My last post gave us an important clue to why this is: fens are fed by groundwater seeps. Not all parts of the fen get equal volumes of calcium-rich water, resulting in different growing conditions and different sets of plant species in each fen zone.
Even the topography of a fen depends on the flow and composition of groundwater. Wetlands are usually associated with depressions in the landscape. However, prairie fens can be found as domes within a wetland, on slopes, and in low-lying areas along lakes and streams. Basically, wherever calcium and magnesium-rich groundwater percolates to the surface in southern Michigan, there could be a prairie fen!
Other conditions such as peat accumulation and disturbances, both natural and human-caused, can play a role in fen vegetation types. According to Michigan Natural Features Inventory (MNFI), these zones in a fen may include wooded fen, sedge meadow, marl flat, and inundated flat. As reported by the Michigan DNR, the sedge meadow is typically the largest part of a fen, while the wooded fen is found in slightly elevated uplands around the edges. Historically, naturally-caused fires and those lit by Native Americans would burn into prairie fens and maintain a more open structure. Today, the wooded fen may occupy more of the fen and the sedge meadow less due to fire suppression throughout Michigan.
Prairie fens can look different from one another depending on hydrology, topography, and fire history, so it may be tricky to determine if a wetland is a prairie fen. Luckily, we can use certain plant species as fen “indicators.” Prairie fens have high pH levels due to the calcium and magnesium carbonates in the groundwater, and some plants are only found in these calcareous conditions. Identifying these specialized “calciphile” plants would bring you to a prairie fen classification without having to identify each plant species in the community. However, the lower the habitat quality, the more difficult it is to determine if a habitat is a prairie fen remnant since cattails and other generalist wetland plants typically increase in abundance after disturbance.
The Michigan State University Extension resource on fen evaluation is helpful for all levels of habitat quality. They recommend surveying in late August and early September when many of the calciphilic species are in bloom. Some of the species listed below are calcium-loving, while others occur both in fens and a variety of other wetland types. Continue scrolling to see prairie fen indicator species found in each of the vegetation zones.
Larix laricina – Tamarack
Eastern Larch, also known as tamarack, is a conifer that breaks all the rules. It is a deciduous conifer that also prefers to grow in the toughest conditions. Tamarack trees are often indicators of all types of peatlands, no matter the pH, but can grow in other wetland types too. Soon they will be turning bright yellow and will eventually lose their needles. The clusters of needles on short shoots that form firework-like sprays from the branches distinguish tamaracks from other conifers in Michigan.
Toxicodendron vernix – Poison Sumac
Similar to tamarack, poison sumac can be found in both acidic and calcareous wetland soils, mostly in southern lower Michigan. I often find that the leaflets of the compound leaves point upwards to the sky. Poison sumac has light gray bark and is less “twiggy,” or finely branched than many other trees and shrubs after it drops its leaves. The photo above (right) shows the awesome fall colors that they will change into. Poison sumac may also be found scattered throughout the sedge meadow zone. Note that species may overlap in several vegetation zones.
Parnassia glauca – Grass-of-Parnassus
Grass-of-Parnassus is not a grass, although the smooth stem does tend to blend in with the surrounding grasses. This flower also has nothing to do with Mount Parnassus in Greece. Grass-of-Parnassus is only found in calcareous conditions, making it an ideal fen indicator species.
Pycnanthemum virginianum – Virginia Mountain Mint
Not sure why the common name has mountain, however, the mint part of the name is very suitable. If you are not sure about the ID of a mint, look for the square stem and rub a few leaves between your fingers. Most mint species have that characteristic aromatic fragrance. Common mountain mint occurs in wet meadows like a prairie fen but is not specific to fens. If you look closely at the flowers they are speckled with purple.
Ohio Goldenrod andRiddell’s Goldenrod
Ohio goldenrod (Solidago ohioensis) is easy to identify by its lower, rosette leaves that get quite large, have one central vein, and are flat. The upper stem leaves do not get as big as the lower leaves. The leaves of Riddell’s goldenrod (Solidago riddellii) fold inward like a paper airplane and taper to a point at the end. They have three veins obvious near the base of the leaf blade. Both species have a flat-topped inflorescence and are calciphiles, meaning they are adapted to calcareous soils.
Marsh Bellflower and Kalm’s lobelia
Marsh Bellflower (Campanula aparinoides) on the left and Kalm’s lobelia (Lobelia kalmii) on the right are both calciphilic species that can easily be overlooked among the larger species in the sedge meadow. It is worth crouching down to see these delicate flowers.
Dasiphora fruticosa – Shrubby Cinquefoil
I see this shrub everywhere in residential landscaping. That being said, it is naturally found in alkaline soils and is an indicator of calcareous conditions. In Michigan, it is mostly found in high-quality wetlands.
Rhamnus alnifolia – Alder-leaved buckthorn
Alder-leaved buckthorn is our only native buckthorn and is generally a calciphile found in high-quality wetlands. Although they are a good indicator of prairie fens, they can be tricky as they look similar to their invasive relative; common buckthorn. I can tell the difference as the leaf tips are more pointed than common buckthorn, and the leaf veins more prominent.
Bog Birch and Sage Willow
These low-lying shrubs are great indicators as they tend to stand out and are easy to identify. Both bog birch (Betula pumila) on the left and sage willow (Salix candida) on the right prefer calcareous soils. Bog birch has small oval-shaped serrated leaves while sage willow has striking white-hoary leaves.
This vegetation zone can be found on the edges of lakes or streams and is dominated by various sedges and rushes. Sedges and rushes are typical in inundated flats and are super cool, but since they are not easy to identify we won’t discuss them in detail here. The Fox Nature Preserve fen is the only prairie fen in our parks with an inundated flat.
Marl flats have strong groundwater seepage and are therefore highly alkaline. Due to the high pH, only species adapted to extreme conditions can survive and the flats are sparsely vegetated. Our township’s prairie fens do not contain marl flats.
Cypripedium candidum – White Lady’s Slipper
The most rewarding part of this season was finally being in on the secret of prairie fens. Now that you have been acquainted with some botanical residents of prairie fens, I hope these communities are no longer strangers. To protect imperiled ecosystems I believe we first need to be able to recognize them as fellow neighbors. Only by understanding its parts can we understand the needs of the community as a whole.
Stay tuned for the final post in the series! We will broaden our lens and discuss human-caused threats prairie fens are facing, and what our stewardship team is doing to help.