Environmental Engineering Reference
In-Depth Information
b
a
c
Fig. 5.5 Different methods of locating samples within a wetland. Different shades indicate
different plant communities. (a) Representative sampling method; squares are samples.
(b) Systematic sampling method with transects; crosses are samples. (c) Sampling with a perimeter
baseline tends to oversample the wetland center (Published with kind permission of
M. Kuchta
©
2014. All Rights Reserved)
5.3.4 Relev ´ Systems
In general, the more objective system of systematically-placed plots using
pre-defined sampling schemes has been adopted by United States ecologists,
while the more subjective system of the relev´ has been used by European
ecologists. Relev´s are becoming more common in the United States wetland
monitoring community (see Minnesota Department of Natural Resources
2007
;
U.S. EPA
2002
), however, due to the ability to obtain representative and detailed
information in a relatively short amount of time. In the hands of a skilled practi-
tioner with expertise in wetland plant identification, relev´s can be very effective.
The basic procedure involves establishing a 100 m
2
plot (400 m
2
for forested
wetlands (Minnesota Department of Natural Resources
2007
)) at a representative
location within a wetland community. By walking through the plot, practitioners
compile a species list, with cover estimates of both life form groups (e.g., ever-
green, graminoid) and individual species. Multiple strata are assessed (tree, shrub,
understory herbaceous), and heights and sociability (clustered, mat-forming, single)
can be estimated. Size information can be taken for trees within the relev
´
plot to
