- March 18, 2016
Bogs are one of the most unique and fascinating types of wetlands in North America. Occurring primarily in the Northeastern U.S. and throughout Canada and Alaska, these distinctive landscapes support uncommon plant life, providing incredible habitat for some rare or endangered species. A bog is a hard bottomed depression in the landscape that has collected and pooled rainwater water for many decades or centuries. With no input from groundwater or streams, the water in a bog is acidic and nutrient poor, which makes for interesting adaptations in the water logged conditions.
A floating mat of vegetation, consisting primarily of Sphagnum moss, can cover the surface of a bog as in the above image. Mats like these can be dense enough to walk on; bobbing up and down and undulating like a waterbed. The stick in the photo has been used to measure the depth of the floating mat, which, in some instances, could be several meters deep.
Over time, the moss fills in towards the center of the bog and may completely cover the entire surface of the water. The edges slowly solidify into soil and can eventually support small shrubs, like cranberry and lowbush blueberries, and eventually trees. This gives a bog a bullseye appearance as rings of different types of vegetation colonize in succession. The bog in the image above is an old ox-bow lake that has been sealed off from the river it used to be a part of. You can see open water in the middle surrounded by rings of sphagnum and other vegetation.
To overcome the acidity and lack of nutrients in a bog, some plants incorporate insects into their diets. The Sphagnum moss in the picture above supports a Round-leaved Sundew (Drosera rotundifolia), a tiny spoon shaped plant with balls of sticky sap that entrap passing bugs. When caught, a struggling insect will only further ensnare itself as the modified leaf slowly closes around it, sealing its fate and providing long term sustenance for the tiny meat-eater.
Another common carnivorous plant found in bogs are pitcher plants. They have an unmistakable shape, as modeled by the modified leaves on a Northern Pitcher Plant (Sarracenia purpurea) pictured in the image above. The leaves form a sealed container that collects rain water into a pitcher shaped pitfall trap. Tiny stiff hairs on the inside point down and make escape for a thirsty explorer quite difficult. The insect can become trapped inside, and will eventually decompose leaving its nutrients for these patient predator plants.
The vegetation surrounding the floating mossy mat has access to nutrients contained in the soil that is created as the bog closes in on itself. The dryer outer edges create concentric rings of varying growing conditions. This provides a recognizable pattern of diversity in the rings around the bog. Above, you can see white pine and some tamarack, or larch (Larix laricina) (a deciduous conifer), which are often found colonizing the outer edges of these changing wetlands.
Among the larch and pine are various species of grasses and forbes like Bog rosemary (Andromeda polifolia), Leatherleaf (Chamaedaphne calyculata), Labrador tea (Ledum groenlandicum), and various orchids; some showy and some rare. Visiting a bog can also yield some exciting wild treats during the right seasons. Explore the slideshow above to see images of the incredible diversity bogs can offer.
Bogs also provide a protected habitat for many rare or endangered bird species that will use the environment for nesting, eating and roosting. The black spruce and tamarack typical in northern bogs supports the uncommon Connecticut Warbler and the Yellow-bellied Flycatcher which often nests down in the moss. Other species that can be found in these northern peatlands include the near-threatened Golden-winged Warbler (shown above), the Palm Warbler, and Northern Waterthrush.
Bogs help preventing downstream flooding by absorbing precipitation. They also capture large amounts of atmospheric carbon. The vast peatlands that make up the northern bog habitat, however, are constantly under threat as they are drained to be used as cropland or as a source of peat. The image above shows a peat mine where bricks of peat are cut from a drained bog. Like other non-renewable resources, peat takes hundreds, if not thousands, of years to form, but can be destroyed in a matter of days.
The Grass Pink Orchid shown here is one of many orchids that are federally listed as endangered or of special concern. While it is not possible to recreate these landscapes, finding alternative fuel sources and protecting the remaining critical bogs from agriculture, mining, and urbanization can help the recovery of the hundreds of endemic species that bogs support.
Adding a bog to your map.
If you are lucky enough to have a bog on your property, you should map it! Let everyone know you have some incredibly productive habitat to protect.
First outline the entire bog area using the wetlands tool. Be sure to include all the rings of the “bullseye”: the open water center if any, the floating mat of sphagnum and other vegetation, and the outer rings of small shrubs and trees.
Then set the Characteristics. Open the Info-window by double clicking on the bog habitat polygon. Give it a name like Backyard Bog and then tell us about it. Under Type, choose bog, and under seasonality choose permanent.