8095

• UCREFRP Catalog Number: 8095
• Author: National Research Council.
• Title: Impacts of Emerging Agricultural Trends on Fish and Wildlife Habitat.
• USFW Year: 1982.
• USFW - Doc Type: Washington, D.C.
• Copyright Material: NO

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the development of special agency groups to enforce them have spurred
evaluation efforts, while, at the same time, techniques have been
evolving for assessing other nonmarket goods and services that can be
applied to wildlife habitat values.
There are a variety of measurement techniques that can be used to
quantify wildlife numbers and habitat quality. These techniques
encompass fish and wildlife population surveys, wildlife community
enumerations, and habitat assessments.
A diversity of techniques has been devised to estimate fish and
wildlife density (i.e., the number of individuals of one species per
unit area or volume). Some are indexes that allow only year-to-year
or area-to-area comparisons; others are total censuses that purport to
count an entire population. These techniques are best summarized for
wildlife by Schemnitz (1980) and for fish by Bagenal (1978).
Traditionally, these estimates have been time-consuming, covering
several seasons or years, a span rarely allowed for in current impact
assessment work. Even methods like the Peterson-Lincoln index require
the marking of a significant number of animals and a high rate of
recapture. Newer indexes that also convert to density estimates are
being developed and tested, so that ultimately such population
assessment may demand less time and money and fewer people (Burnham et
al. 1980).
To assess the density of the numerous wildlife species coexisting
in an area is an enormous task. Nevertheless, some effort must be
made to determine the numbers of different species that occur (species
richness) and their relative abundance. Whereas line or spot censuses
may provide information on species richness, data necessary for total
censuses (for calculating species density indexes) are difficult to
obtain. with small birds, mist netting has been used regularly, and
fisheries scientists have used nets and traps of various sizes.
Mammalogists have combined live and dead traps to assure
representation of all species for an index to relative abundance. All
these techniques have problems of inaccuracy and are time-consuming,
but they are being improved.
Standard vegetation assessment techniques have been used to
sample the habitats of terrestrial wildlife. These include cover
maps, quadrats, transects, and bisects. Aquatic habitats are most
difficult to appraise and involve physical parameters such as depth,
size of substrate, chemistry, and vegetation. All are difficult to
relate to how fish and wildlife use the habitat, and many assessments
of habitat use fish or wildlife density as a measure of carrying
capacity and, thereby, quality of the habitat. Again, these
measurements are time-consuming and often require several seasons of
study because they involve observational rather than experimental
approaches.
New qualitative approaches to habitat assessment have been
developed by several federal agencies, which are often pressured to
make judgments or plan for future resource management needs with
little scientific justification. The U.S. Fish and Wildlife Service
is now testing a system called the Habitat Evaluation Procedure (HEP)
(Schamberger and Farmer 1978). This is a community-oriented approach