Geoscience Reference
In-Depth Information
2
Wetland criteria
2.1 Defi nitions
different kinds of mires in dialects of northern
Finland, including the terms aapa, palsa and
tundra, which are used internationally in eco-
logical research nowadays (Aapala and Aapala
1997).
Still, all these names and terms do not specify
the basic characteristics of wetlands. A dei ni-
tion of what is a wetland often depends on
who is asking the question and what develop-
ment, exploitation, preservation, or study is
proposed for a particular wetland site. The fact
that wetlands may dry out from time to time
complicates the attempt to dei ne wetlands in
a simple fashion. In fact, some wetlands may
be dry more often than they are wet. With
applications ranging from urban real estate to
wildlife nature refuge, a great many points of
view may be expressed for proper dei nitions,
classii cation, and management techniques for
wetland environments.
In the United States, one of the earliest
modern dei nitions was developed by the U.S.
Fish and Wildlife Service in the 1950s for catego-
rizing waterfowl habitat.
Many dei nitions for wetlands have been pro-
posed and utilized over the years. In fact, more
than 50 wetland dei nitions may be cited (Dugan
2005), ranging from the broadly inclusive dei ni-
tion of the Ramsar Convention to much more
specii c and restricted dei nitions. The approach
taken by Ramsar is simply to name typical kinds
of wetlands with common words familiar to the
public.
Wetlands are areas of marsh, fen, peatland or
water, whether natural or artii cial, permanent or
temporary, with water that is static or l owing,
fresh, brackish or salt, including areas of marine
water the depth of which at low tide does not
exceed six metres (Ramsar 1971).
Many terms derived from several languages
have come into English usage to describe wet-
lands of various types in different geographic
settings
-
bayou, billabong, bog, fen, mangrove,
marsh, muskeg, playa, pocosin, sabkha, slough,
swamp, and wad
-
to name just a few (see Glos-
sary). Many of these names are now united
under the general term mire, which refers to
any wetland that accumulates peat. Equivalent
words in other European languages include
mose (Danish), tourbière (French), Moor
(German), bagno (Polish), suo (Finnish), soo
and raba (Estonian), pântano (Portuguese) and
boloto (Russian). At least 19 words refer to
The term “wetlands” . . . refers to lowlands
covered with shallow and sometimes temporary or
intermittent waters. They are referred to by such
names as marshes, swamps, bogs, wet meadows,
potholes, sloughs, fens and river overl ow lands.
Shallow lakes and ponds, usually with emergent
vegetation as a conspicuous feature, are included
in the dei nition, but the permanent waters of
