Wetlands – What’s in a name?
When someone uses the terms marsh, swamp, bog or morass, most of
us have a mental image of what that entails. But is that image
right? What officially is a swamp? What is the scientific
difference between a fen and a marsh? Or a bog? Let’s see if we can
sort this out a bit.
In physical geography, a wetland is an environment "at the
interface between truly terrestrial ecosystems and aquatic systems
making them inherently different from each other yet highly
dependent on both" (Mitsch & Gosselink, 1986). In essence,
wetlands are ecotones (a community of mixed vegetation formed by
the overlapping of adjoining communities, in this case water-based
and land-based). Wetlands often host considerable biodiversity and
endemism (endemic: specific to an area; here, plants and animals
unique to the area). The United States Army Corps of Engineers and
the United States Environmental Protection Agency jointly define
wetlands as: Those areas that are inundated or saturated by surface
or ground water at a frequency and duration sufficient to support,
and that under normal circumstances do support, a prevalence of
vegetation typically adapted for life in saturated soil conditions.
Wetlands generally include swamps, marshes, bogs, and similar
areas. The constant or regular saturation of the soils in a wetland
leads to decreased oxygen levels in the soil. Plants that live in
the wetlands have adapted to this, some by forming exposed root
systems so they can exchange gasses separate from the soil, and
some by just adapting to the reduced levels. Some plants have
adapted so well, and are so prevalent, that the wetland areas are
named for them. A Mangal or Mangrove swamp is a wetlands area
dominated by the presence of Mangrove trees.
The area we are going to visit today is frequently referred to
as a Tamarack Swamp. A tamarack-rich swamp is a deciduous,
needle-leaved wooded wetland. The Tamarack, or American, Pine tree
(also known as the Larch, for all of you Python fans!) is a
deciduous tree, found from Alaska to Newfoundland, south to British
Columbia, Alberta, Saskatchewan, Manitoba, Minnesota, Wisconsin,
northern Indiana, Ohio, Pennsylvania, and New Jersey. It thrives on
acidic, poorly drained soils and does not tolerate warmer climates
or dry substrates. It is what is called a pioneer species; it is
often the first tree to invade open bogs and burned peatlands as
they start to fill in, and eventually gives way to other conifers
as peat firms up; on poorly drained sites by Black Spruce; on rich
sites by Black Spruce, followed by Balsam Fir, White Cedar and
eventually swamp hardwoods. The Tamarack was one of the earliest
species, along with spruce, to follow the retreating ice northward
at the end of the last ice age. The Chippewa (or Ojibway/Ojibwe)
word for tamarack is muckigwatigí, meaning swamp tree.
But why swamp? Why not marsh, or fen? Each term has a specific
set of parameters that defines it, although there is some overlap
of them, and a few are interchangeable.
*A bog or muskeg is acidic peat land (peat bog).
*A moor was originally the same as a bog but has come to be
associated with this soil type on hilltops.
*A moss is a raised bog in Scotland.
*A fen is a freshwater peat land with chemically basic
(which roughly means alkaline) ground water.
*A carr is a fen which has developed to the point where it
supports trees. It is a European term, mainly applied in the north
of the UK.
*A marsh can be fresh water, salt water, or brackish.
*A fresh-water marsh's main feature is its openness, with
only low-growing or "emergent" plants. It may feature grasses,
rushes, reeds, typhas, sedges, and other herbaceous plants
(possibly with low-growing woody plants) in a context of shallow
water. It is an open form of fen.
*A coastal salt marsh may be associated with estuaries and
along waterways between coastal barrier islands and the inner
coast. It may be converted to human use as pasture or for salt
production.
*A brackish marsh has water which is only slightly salty.
The most frequent place to find brackish water is where freshwater
and salt water meet, such as the mouth of a river where it flows
into an ocean.
*A swamp is wetland with more open water surface and deeper
water than a marsh. In North America, it is used for wetlands
dominated by trees and woody bushes rather than grasses and low
herbs, but this distinction does not necessarily apply in other
areas, for instance in Africa where swamps may be dominated by
papyrus.
*A mire (or quagmire) is a low-lying wetland of deep, soft
soil or mud that sinks underfoot.
*A dambo is a shallow, grass-covered depression of the
central and southern African plateau which is waterlogged in the
rainy season, and usually forms the headwaters of a stream or
river. It is marshy at the edges and at the headwater, but may be
swampy in the centre and downstream.
*A bayou or slough are southern United States terms
for a creek amongst swamp. In an Indian mangrove swamp, it would be
called a creek.
*A constructed wetland is artificially contrived wetland,
intended to absorb flash floods, clean sewage, enhance wildlife or
for some other human reason.
*A pocosin is a bog-like wetland dominated by fire-adapted
shrubs and trees, found mainly in the southeastern United States on
the Atlantic Coastal Plain.
Even with these guidelines, sometimes the line between the
categories is a little blurry. I have also heard this area called a
Tamarack Marsh, although the presence of trees seems to put it more
into the swamp category. But throughout the year, the water level
varies, and so there may be no water standing where you can get to,
on the edges of it, though the soil is never really dry.
Additionally, as with the description of the dambo, one type of
wetland can border another, as in the rings on a target. What
starts out marshy or boggy may turn swampy as you work your way
in.
To log this Earthcache, you will need to do
the following:
Go to the posted coordinates. It is the only legal parking area
for the
Al Sabo Land Preserve. Attempts to
park in any other area may be costly to you. From there, go to
N42° 13.305 W85° 40.478. This overlook looks out into the
swamp area. See how thick the cover has become, you can barely see
that the ground is less than firm down there. Then proceed to
N42° 13.286 W85° 40.524. This is the edge of the swamp. You
will need to go at least 100 ft in off the trail, to make sure you
are getting a good result. Answer the following questions for me,
via email.
1). Is there any visible
water?
2). If there is water, take a pH
reading. If there is no water, then you will need to take a pinch
of soil and dilute it in some fresh water. Then take a pH reading
of that. The water needs to be fresh, but not necessarily sterile,
purified or distilled. Tap water will do just fine. I’d encourage
you to take some water and a small container to do this in with
you, just in case. But if you forget, you can take a pinch of soil
with you to do your testing. If you have one of them fancy soil pH
testing kits, that’s okay as well. (Don’t feel bad if you don’t,
neither do I.)
3). Take a picture in which
(minimally) your face is identifiable, and I can see the overlook
in the background, and post it with your log.
That’s it. Nothing more. Although, if you want to complain to me
about having to hike into Al Sabo yet again, please feel free. I’ll
be happy to commiserate with you. Additional pictures of your visit
are always welcome. Logs which contain your answers may be
summarily deleted by me. Send me an email, then log your smiley.
You do not have to wait for a reply from me before logging.
Enjoy your foray into Al Sabo, it really is a beautiful place to
hike and ride. If you haven’t already, check out some of the many
traditional caches placed here for your pleasure. I’ve been told
that you can do them all in one day (albeit a long one), but I
prefer two myself. And mark your parking!