Into the bog

Muskegs are an ideal habitat for berry pickers and curious naturalists

Posted: Sunday, September 25, 2005

When hikers think of Juneau's trails, they usually think of rain forest. But many local trails provide easy access to a special habitat: the muskegs (or, more properly, bogs). Well-known to berry pickers for their bog cranberries, cloudberries and lingonberries, muskegs can also be fascinating places for a curious naturalist. The acidic, low-nutrient soils are home to several species of insect-eating plants, which supplement their poor supply of soil-derived nutrients by digesting captured insects. Two species of sundews use sticky hairs on their leaves to catch and digest small flies and even large dragonflies. Butterworts, sometimes called bog violets, trap insects on their slimy leaves.

The poor soils also support scattered populations of small pine trees, a variety of lodgepole pine called shore pine. Most of the pines in the muskegs are tiny, but despite their diminutive size, these trees may be several hundred years old, their stunted growth a result of the poor soils. The little pines tend to be found on hummocks, raised slightly above the general level of the muskeg and therefore slightly drier. Although muskegs are generally wet, seeds that land on the surface of the mosses often die, perhaps surprisingly, of desiccation. These hummocks are also one of the few places one finds ant colonies in nonurban parts of our area.

Most muskegs are dotted with shallow, mucky-bottomed ponds. Flying over the ponds in summer are mighty predators of the insect world - the dragonflies and their daintier relatives, the damselflies. They may be foraging for small insects, but they are focused on the ponds for another reason. Females come to the ponds to mate and lay eggs, and males are ready for them. Males compete intensely with other males and guard their females closely, to deter other males from mating with them, and in some species they are able to remove any sperm deposited by a previous male! Male and female fly around in tandem until sperm are transferred from male to female, and in some cases, a male attends the female while she lays her eggs in the water or emergent vegetation. The eggs produce aquatic larvae that are voracious predators of the underwater realm, using a remarkable extensible "lip" to capture other insects and even small fish.

These aerial dragons have their own predators, of course. If you are lucky, you might see merlins (a small falcon) cruising rapidly across a muskeg in pursuit of dragonflies. Another fairly uncommon bird in our area is the olive-sided flycatcher, whose ringing song of "Quick, three beers" can sometimes be heard from a treetop at the muskeg edge. If you venture too near their nest, greater yellowlegs (a bird of tideflats and shores, in winter) will shout alarms from the pine tops and may even swoop down at your head.

Muskegs support a lovely array for flowers found in no other habitats, such as bog rosemary, with its little pink bells, bog azalea, with its flashier, broader pink blooms, and the aromatic white bog orchid. Showy flowers are the plants' way of getting pollen from one individual to another, by attracting animals as pollen-carriers. So, although we often think of plants as relatively inert (compared to animals), the reproductive sagas of intense competition for mates can occur among plants, even though they cannot sing or dance or fight as animals can - the plants compete with each other by showing off their floral displays, scent, and offering nectar.

The easiest access to good muskegs can be found on the Eaglecrest road or near the Point Bridget trailhead, out the road. Closer to town, a short uphill junket on the Dan Moller, Spaulding Meadows, or Mount Jumbo trail gets you to other beautiful bogs.

• Mary F. Willson is a retired ecology professor and a Trail Mix board member.

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