Monday, March 3, 2008

Skunk cabbage, first flowering...

Ross Lake Wildlife Area is an easy place to find the first flowers of spring. During February and March, hundreds of skunk cabbage flowers rise from muck found just a few feet north of the parking area at the end of Hydell Road, along the lakes west shore.

First flower; Skunk cabbage (Symplocarpus foetidus) blooms through snow at Ross Lake Fen, Ross County, Ohio.

Ross Lake Wildlife Area is just east of Chillicothe, Ross County, Ohio. The fen is small, a little known slope-fen* formed along the northeast flank of a ravine cut into a sandy glacial terrace left by Illinoisan glaciation (the glaciation prior to the most recent Wisconsin). It's easy to find, but walking through it will be a challenge--you'll need rubber boots!

I call the place, "Ross Lake Fen" because I'm not aware of any other name used for this obscure group of seeps. This fen is located seven miles south, as crows fly, of Kinnikinnick Prairie, the more recognized but degraded fen frequently identified as the furthest south fen in central Ohio.

Skunk cabbage is exothermic, giving off heat***. Its warmth, and foul odor (often described as skunk spray with garlic) carried on the wind, are very attractive to early pollinating species looking for winter kill carrion. A plume of CO2 resulting from high plant respiration may also serve to attract pollinators. Pollinators are rewarded with warmth inside the flower.

Wetland botanists might classify this area as a series of forest seeps, more particularly, skunk cabbage seeps**. A close look, and we find the hydrological and chemical characteristics of a fen, but few calciphiles--plants that love alkaline conditions.

I'd classify this series of seeps, a fen, by functional definition. They result from geological influence driving groundwater flow. Here, groundwater seeps out of a ravine slope cut into a sandy glacial terrace. The unconsolidated terrace sand rests on a layer of clay, a hardpan. The hardpan prevents downward flow, pooling groundwater. Where the hardpan intersects the flank of the ravine, groundwater seeps out. A "perched" water table, atop the clay, drives the seeps. Organic muck is accumulating wherever seep water trickles out along the slope.

The wet green area seen here is a raised mound of organic muck accumulating where groundwater seeps out. The view is east from the western margin of the fen area. Ross Lake is seen at upper right. Skunk cabbage is found in many of these raised areas along the glacial terrace's north-facing ravine slope.

*Amon JP, Thompson, CA, Carpenter QJ, Minor J. 2002. Temperate zone fens of the glaciated midwestern USA. Wetlands 22: 301-317.
**Mack, John J. 2004. Integrated Wetland Assessment Program. Part 2: an ordination and classification of wetlands in the Till and Lake Plains and Allegheny Plateau regions. Ohio EPA Technical Report WET/2004-2. Ohio Environmental Protection Agency, Wetland Ecology Group, Division of Surface Water, Columbus, Ohio.
*** See here for discussion of exothermic plant physiology


Tom said...

Hi Tom.

Thanks for the link to my blog. Interesting stuff you have presented. Rick G. and I have often talked about the need for a woodland seep plant community to be described for Ohio. It certainly is a real community. Chrysosplenium americanum might be another indicator plant.

Take a look at this description from NatureServe. This "alliance" may fit with these types of habitats.

Symplocarpus foetidus - Caltha palustris Saturated Herbaceous Alliance

Ohio is listed as question mark. But surely, this would fit here in Ohio.


Tom Bain said...

Hi Tom,
I see my link on your blog as well, thanks. The Saturated Herbaceous Alliance looks like a good description for the "fen" we call "Gateway Fen" which occurs very near where Paint Creek enters the shale gorge of Paint Creek just a few miles west of Chillicothe near Buzzard's Roost. The skunk cabbage and march marigold are dominates with lesser amounts of marsh fern-I don't recall noting Angelica, but I'll bet it's there. This fen gets continuous moisture from a Wisconsin age terrace and is more typically on a flat between the hill and a stream draining it.

The Ross Lake "fen" has no marsh marigold that I've noticed but I think there is golden saxifrage--I think it can be seen now as tiny green leaves but I could be mistaken.