Burroughs Backyard

Backyard biology from a field ecologist's perspective

Circumneutral bog lakes

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Circumneutral bog lake”. The first time I used that expression in my current position at the DEC, a few people started chuckling. It ends up that hearing someone use that expression stamps them as somebody trained in habitat classifications by Hudsonia, a non-profit that does ecological studies and mapping efforts in the Hudson Valley. My coworkers don’t chuckle because it’s a bad thing, it’s just indicative of your ecological history in the same way that talking about a “pahty” might mark you as a Bostonian. In fact, if you do a google search for “circumneutral bog lake,” the first page of results are all Hudsonia-related – either part of their website or that of a town that’s had habitat mapping completed by Hudsonia.

So, what is a circumneutral bog lake? Here’s the definition from Hudsonia’s fact sheet:

A circumneutral bog lake is a spring-fed, calcareous water body that commonly supports vegetation of both acidic bogs and calcareous marshes. The lake is underlain by deep organic sediments; floating mats of vegetation and drifting peat rafts are often present. This is a rare habitat type in the region, known to support many rare species.

The upshot is that it’s a really, really biologically cool place to be.

I had the unintentional opportunity to go swimming in a circumneutral bog lake last week, and it took a humorously long time to end the experience. “How does one unintentionally go swimming in a circumneutral bog lake?” one might ask. Well, there was a kayak involved. (“Ahhh, that makes it much clearer!”)

Here’s the longer version of what happened:

Circumneutral bog lakes tend to support floating vegetation mats and water lilies, and these, in turn, tend to support breeding populations of Northern Cricket Frogs (Acris crepitans). While common in the southern portions of their range, cricket frogs are endangered in NY state: historically they had limited populations because NY represents the northern extreme of their range, but they’ve also undergone drastic population reductions and local extirpations in the past few decades.

I’ve been doing a lot of work with northern cricket frogs, trying to learn about their movements between habitats at different parts of the year (I’ll write more about that process in another post). This means that during their breeding season, which lasts from late May until mid-July, I’ve been doing some capture surveys in their breeding habitat. And the one that we’ve been targeting is both amazing and intense.

To access it, we launch kayaks into a small body of water with thick water lilies (after hiking/dragging/carrying the kayaks through a willing someone’s backyard and their hilly woods), and paddle about 20 meters to where it’s too thick to go any further. At that point we climb out of our kayaks in waders, carefully using submerged portions of those floating vegetation mats to stabilize ourselves and keep from swamping our waders. We drag our kayaks through a narrow channel that weaves between floating tussocks of sedge, flowers, small shrubs, and poison sumac, sometimes up to our knees (and trying to climb over higher muddy spots) and sometimes within a few inches of where our chest waders top out. Eventually we get to a point where we can again carefully get back into the kayaks (still in waders, mind) and paddle in some open water amid floating mud patches and lots and lots of lily pads.

It’s awesome. The first time I visited this circumneutral bog lake, I couldn’t get over the beauty of it. There are rare bog plants, including carnivorous sundews, bladderworts, and pitcher plants. There are grass pink orchids, marsh cinquefoil, and bog rosemary. I believe I saw isoetes, an aquatic fern relative, for the first time. Then there’s the larger-scale beauty of the sunset over mountains in the distance, with tussock grasses and cattails rising above the water lilies that surround you.

marsh cinquefoil

marsh cinquefoil



bog rosemary

bog rosemary

grass pink orchid

grass pink orchid







As you can imagine, though, the entire process is a little cumbersome, especially since it happens around dusk (and we navigate back out by headlamp). But that process, in itself, is not how I ended up swimming in a circumneutral bog lake. Though awkward and with the potential for getting wet and exhausted, the navigation isn’t treacherous at all (don’t worry, relatives!), and we always have companions and wear PFDs.


waiting for dark

Once dusk sets, the cricket frogs get much less skittish as the males call in their gick-gick-gick cricket-froggish way and the females hop among the lily pads and over the floating mud mats. It gets to the point that you can slowly glide up next to one in your kayak and snag it with your hand. Sometimes they even hop onto your boat.

 male callingboat frog






It was in my overeagerness to capture a frog that I made my error. Leaning too far to get one that had hopped 3 lily pads away, water started to flow into the kayak. I slipped myself out, remembering from my canoe days that it’s easier to re-enter a boat with very little water in the bottom than one with a lot of water. Unfortunately, I forgot I was wearing waders. They filled; I tried to get back into the boat without accounting for the complete heavy-awkwardness that filled waders impart, and managed to completely swamp the kayak. After struggling awkwardly for a little while (filled waders make kicking your feet to move forward pretty much useless), I managed to use my kayak paddle to gondola my way over to the surrounding vegetation, pushing against the mucky bottom that was too deep for my feet, and dragging my swamped kayak along with me.

At this point, remember that the surrounding vegetation is composed of those wonderful, gorgeous, healthy-habitat floating vegetation mats. Whoops. I eventually made my way out of my waders, which made it possible to get up onto one of the mats….but they’re not buoyant enough, or large enough, to empty a full-of-water kayak. Ugh. By this point my companions had my gear safely (waterlogged-ly) distributed to their kayaks. After some unsuccessful attempts to get the kayak high enough on the vegetation mats to empty it, we found a nearby beaver lodge that we could use as high ground. Thank you, wetland engineers!

I spent the rest of the night in the boat without waders, until I eventually put them back on for the pull-the-kayak-through-the-veg part of our journey (to protect me from the substrate). It was good except for one LARGE leech that I found crawling across my pants leg – eeewww! That elicited the most girly shriek I think I’ve ever uttered.

Luckily, my coworkers were good sports through all of this. I felt like a numbskull, but was also glad it was me, since I’ve had enough small craft experience that it doesn’t worry me too much to be out of and alongside my boat. It just presents problem-solving opportunities! And, the chance to learn that it’s a good idea to put a belt or rope around the middle of your waders – then they don’t swamp and even act as a flotation device!

And the chance to appreciate circumneutral bog lakes in a whole new way! 


carnivorous sundews

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