level
Riparian-riverine community classification may be defined by riparian vegetative
type. Managers assume that the constituent communities of a taxonomic unit will
respond in the same way to similar management (Platts et al. 1987). Differing from
forest or rangeland terms, riparian communities are classified by present rather
for riparian community classification.
Transects, Maps, and Aerial Photography for Habitat Measurements. Mon-
itoring along a transect is useful for consistent collection and organization of
stream habitat data. Figure
illustrates the arrangement of transects for stream
treatment and control measurements perpendicular to the main direction of flow.
where livestock are excluded, is the
In the figure, the livestock
treatment. Figure
shows the use of cross-sectional transects (transect 35 and
26) and medial transects (transects ED, DC, etc.) for stream reach habitat
measurements. Figures
and
show types of measurements made for a
detailed cross-sectional survey. As in Figures
and
some stable feature
of the landscape, such as a stake, or fence post may be used to mark the beginning
and end of each transect and as a reference for future data collection.
Drawing a diagrammatic map of a stream reach may require more measurements
at the onset than transects, but more details may be quantified, and stream features
that remain unchanged in the original map may be retained for future evaluations.
An example of an idealized stream section is given in Figure
and a
diagrammatic map with habitat areas determined by planimetry, or a
aided digitizing tablet, is shown in Figure
Photographs may also be used for
documenting habitat conditions not easily described or measured.
Habitat requirements for the entire range of the species must be considered, not
just the monitoring station (Hendricks et al. 1980). For restoration of a fishery in
a second-order stream impaired by sediment, monitoring only sediment delivery
to that reach may not quantify all relevant aspects of restoration. If spawning
habitat and upstream macroinvertebrate food sources are not protected, then the
downstream fishery may not recover
and Dudiey 1981). Tributary streams
may also be important as spawning areas for some lake fishes.
can be used to identify many characteristics of habitat for a large
area. However, ground sampling is necessary to supplement
photos through
ground truthing and identification of some species. Platts et al. (1987) provide a
list of variables and methods for monitoring with aerial photos. Habitat variables
to monitor grazing impacts include areas covered with vegetation and bare soil,
stream width, stream channel and streambank stability, and width and area of the
riparian zone (Platts et al. 1987).
Fish Habitat Models. Several models have been developed to aid in the
evaluation of stream fish habitat. Understanding the limits of the model through
a review of assumptions, the development data set, and the geographic range will
help to avoid misapplication. Habitat models are not likely to be able to estimate
fish abundance or biomass since populations may be limited by the impact of
pollution or other nonhabitat factors. However, habitat models can provide a
standardized framework for consistent habitat monitoring and modeling.
The US Fish and Wildlife Service has proposed the use of the Habitat Evaluation
Procedure (HEP)
et al. 1982) and the
Flow Incremental Meth-
odology (IFIM) (Stalnaker
models share a component called
that is based on the assumption that fish population fluctuations are driven by
physical habitat variables such as depth, velocity, substrate, and cover. If the
3.22
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