Geoscience Reference
In-Depth Information
Glossary of wetland types and terms
This glossary includes common names as well
as some specialized or local terms for wetlands
and their physical, chemical, biological, or cul-
tural conditions. Names of individual plant and
animal species are not included, however.
Neither are names for various governmental
agencies and most private organizations. The
dei nitions are based mainly on Neuendorf,
Mehl and Jackson (2005) and Mitsch and Gos-
selink (2007), as well as many other sources.
See index for additional names, terms, and geo-
graphic locations.
change based on new information or
conditions.
Aerenchyma -
Porous tissue with large, air-
i lled spaces between cells of stems and
leaves that allows oxygen and methane to
diffuse between submerged aquatic plant
roots and the air and provides buoyancy.
Aerobic -
Referring to the presence of oxygen
or an oxidizing chemical environment.
Albedo -
Rel ectivity of the Earth's surface and
atmosphere for visible light and invisible
radiation.
Allogenic -
Refers to wetland changes induced
by external forcing factors, which are of suf-
i cient magnitude to inl uence or alter inter-
nal processes.
Altithermal -
Climatic optimum of warmer-
than-present conditions that existed in the
middle Holocene,
Aapa -
Mire in high latitude or altitude in which
gently sloping (
1°) land forms narrow ridges
of peat that are separated by deep pools
(l arks). Ridges and pools are elongated per-
pendicular to slope. Also known as ribbed
fens, patterned fens, and string bogs. Typi-
cally found in boreal or subarctic settings,
south of palsa peatland. Etymol: Sami.
Acequias -
Spanish term for a ditch-and-canal
system used for irrigation; specii cally a com-
monly owned and operated irrigation system
in the San Luis Valley, Colorado, United
States.
Acid rain -
Precipitation with pH
<
8000 to 4000 calendar
years ago. Also known as the hypsithermal
or Holocene thermal maximum (HTM).
Amber -
Fossil resin derived primarily from
extinct conifer and evergreen trees that may
contain extinct animal and plant remains, the
most common being winged insects.
Amphibious plants -
Those plants that are
able to live both on land and in water and
may grow as either submerged or emergent
types. The emergent morphology may be
quite different from the submerged plant
form.
Anadromous i sh -
Species that spend part of
their lives in fresh water, usually to spawn
∼
5.
Acrotelm -
Upper portion of the soil, in which
oxygen is present and decay is relatively
rapid. Zone generally above the long-term
average water table.
Adaptive management -
Structured process,
approach or plan that allows l exibility and
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