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Purpose:
The purpose of this Challenge Cost Share project is to collect and
compare insect assemblages at selected wetland sites using a combination
of light traps and water traps (fallout traps). Insects will be sorted
to order, counted, and selected groups (Hymenoptera, Trichoptera,
Plecoptera and Ephemeroptera) identified to lower taxonomic resolution
(family, genus or species).
Watch
Erica pick up the Fallout Traps (Real Video)
Background:
There is a current need to monitor, classify, and analyze wetlands
in order to assess management techniques, mitigation projects, restoration
efforts, land-use impacts, and environmental contaminants. Aquatic
insect larvae are frequently used as biological indicators in freshwater
ecosystems because they are a diverse group that responds to environmental
conditions in a predictable fashion. However, the use of aquatic
insects as integrative, biological indicators has been largely restricted
to lakes, rivers, and streams; perhaps due to difficulties associated
with sampling immature insects in wetlands. Sampling in wetlands
is difficult and can be destructive to wetland vegetation. Taxonomic
identification at the genus and species level can be quite difficult,
especially for some groups of immature insects (e.g., Trichoptera).
In spite of these difficulties associated with the sampling of immature
insects, there are many advantages to the use of insects to characterize
wetlands. First, insects are ubiquitous in wetlands throughout the
world and information exists on their ecological requirements and
tolerance to environmental stress. Second, insects respond quickly
to change and integrate environmental variability over their life
span; therefore, unlike most physical characters, insects can be
used to measure past, as well as present, conditions. Finally, insects
provide a measurement that is not directly manipulated by managers,
as opposed to vegetation and various vertebrate taxa
We initiated this survey
of insects at the West Eugene Wetlands in 2001. We are sampling,
using both light traps and fallout traps, at six locations at two
sites.
S. Balboa Site
Emergent
Marsh
(N44 02.984,
W123 10.740)
This is the site of
an old airstrip, which was removed 4 years ago. At this site,
we are sampling insects in a restored wet prairie, an emergent
marsh, and a remnant wet prairie. The remnant wet prairie
is now covered with blackberries and shrubs and a controlled
burn or brush hogging is planned. There are several small
areas of cattail near the restored runway.
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Greenhill
Site
(N44
03.779, W 123 12.528)
This
site has multiple landowners: ODOT owns 60 acres near the
tracks and BLM and the City of Eugene own the rest. This site has multiple year restoration areas
and a remnant wet prairie.
Near the NW corner is the older area (seeded in 1999
with 50-60 species) now in its third growing season. There are a number of transplants and experimental
plots (mychorhizae and fertilized plots) in this area.
Some of these areas are being restored and managed
using a combination of solarization, shallow discing, burning
and hand weeding.
We
are sampling insects in the south central portion of the site,
which has a 1 year old restoration site. We are also sampling at a remnant wet prairie
near the eastern side (between a drainage ditch and the road)
that is somewhat wooded and an untreated agricultural area
along the western side of the site.
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Hand
weeding teams in the 1 yr old restoration area at the Greenhill
site.
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Contact Information
Wetland & Watershed Assessment Group
Earth Design Consultants, Inc.
230 SW Third St., Suite 212
Corvallis, OR 97333
(541) 757-7896
(541 757-7991 FAX
http://www.earthdesign.com
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