Wetlands
Wetlands and geology are not a connection most people think of
and yet geology plays a vital role in the development and
maintenance of wetlands. The Geological Survey Bureau has been
involved in several wetland studies, most prominently an
investigation of groundwater-fed wetlands known as fens. Iowa
fens are small, nutrient-rich peatlands with circum-neutral or
higher pH and a dominantly calcium-bicarbonate water chemistry.
Although fens are common components of the landscape in many
northern European countries, parts of Canada, and some northern
U.S. states, little was known about the small hillslope fens
found in the midwest and prairie states. Fens may be one of the
rarest wetland communities in the midwest and are valued for
their botanic diversity. Over 200 species of plants, many of
which are endangered, threatened, or rare, are known to occur in
fens; some are found only in fens. Since these habitats depend on
groundwater inflows, an understanding of their geologic setting
and hydrologic characteristics is necessary for successful
management and protection schemes.
The Iowa fen study has led to a much better understanding of
fen wetlands. Several papers have been published or are in press,
including one on the geologic setting of Iowa fens (Fen Age and
Development, abstract),
one on the age and developmental history of fens in Iowa (Fen
Evolution, abstract), and
one on management issues related to fens. Other papers are being
written which will detail water movement and water quality in
Iowa fens. Also available in the Browse Area is a general article
on fens (Fens), and
the history of peat usage (Peat)
and production (Peat
Production) in Iowa, as well as a general article on (Wetlands). The Iowa
State University Extension Office also has available three
non-technical publications on fens. For information on these
publications contact Extension at (515)294-4576.
The Geological Survey Bureau is just beginning a new wetland
project to track the hydrology of a restored prairie pothole.
Pothole restoration has been underway in Iowa for many years and
many thousands of acres have been restored. However, there has
been some concern that restoration has not been able to restore
some functions of the wetland, particularly the sedge edge which
is so valuable to many species. Few if any studies have been done
which compare the hydrology of a natural pothole wetland to a
restored site. This project will monitor surface and groundwater
levels over time at two sites on a National Guard base in central
Iowa. Concurrent studies will track vegetative and faunal use at
the sites.
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