Technique for Structuring Wildlife Guilds to Evaluate Impacts 
on Wildlife Communities 
by 
Henry L. Short and Kenneth P. Burnham 
U.S. Fish and Wildlife Service 
Office of Biological Services 
Western Energy and Land Use Team 
Fort Collins, Colorado 80526 
Abstract 
This paper describes a technique for ordering wildlife information according to physical strata and 
vegetative structure so that a variety of statistical analyses can be accomplished. Individual wildlife 
species are assigned to cells in a species-habitat matrix on the basis of feeding and breeding activities 
within physical strata in representative types of vegetative cover; the cells within the species-habitat 
matrix are assigned numeric values. The statistical analyses are thus based on the areas that individual 
species occupy within the species-habitat matrix. Computer graphics are used to represent the structure 
of wildlife communities and cluster analysis routines are used to describe the potential wildlife guilds 
that may exist in different vegetative communities. Different numbers of wildlife guilds will occur in 
different types of cover within a potential natural vegetation type. Furthermore, the number of wildlife 
species and presumably also of wildlife guilds present within a type of cover is modified by physical 
attributes of the vegetation within that cover type. The products of this analytical technique may be 
suitable for evaluating habitat quality, impact assessments, regional inventories and assessments of wild- 
life resources, and land-use planning activities. 
We describe in this paper a technique for relating wild- 
life species to the structure of vegetative communities so 
that one can predict the impacts on wildlife communities 
that will occur as vegetative communities are changed. 
The technique has a numeric basis so that a variety of 
computer simulations and analyses can be accomplished to 
describe wildlife-habitat relationships. 
The concepts in this paper were developed with a data 
base compiled for the eastern ponderosa pine (Pinus pon- 
derosa) forest (Kiichler 1964, type 16). Data about wildlife 
species occurring in southeastern Montana and northeast- 
ern Wyoming were determined from the literature, were 
organized according to a species-habitat matrix, and 
were subjected to statistical analyses. Results of those 
statistical analyses include graphic illustrations that indi- 
cate the dependencies of individual species on the structure 
of vegetative cover types, and the development of groups 
of species, called guilds, which utilize similar food sources 
and breeding niches within habitats for their support and 
well-being. The structure of wildlife communities that 
might exist within three different cover types of the eastern 
ponderosa pine forest type is presented in detail and lists of 
guilds (and their membership) within each type of cover 
are described. 
Development of our technique has been strongly influ- 
enced by the current state of the art for evaluating habitat 
quality for wildlife, reviewed in detail by Erickson et al. 
(1980). We have been especially influenced by (1) models 
that evaluate habitat quality on the basis of the habitat’s 
ability to satisfy life requisite needs of selected animal 
species, (2) prediction models of wildlife habitat quality 
that rely on map-based criteria identified from aerial pho- 
tography, (3) computerized and noncomputerized data 
bases for wildlife species, and (4) computer simulation 
models of ecosystem functions. 
Our wildlife guilds are aggregations of species that tend 
to utilize the resources of a habitat in a similar manner. 
These guilds are closely tied to the structure of vegetation 
and have a numeric basis so they can be used in habitat 
simulation and modeling. Thus, if changes in the structure 
of vegetation can be predicted from some land use, then 
the probable impacts on wildlife guilds caused by change 
can also be predicted. In addition, we distinguish between 
primary and secondary consumer activities for an indi- 
vidual species, if appropriate, so that an omnivorous 
species can be shown as competing with one group of 
species as a primary consumer and with a second group of 
species when acting as a secondary consumer. Our guilds 
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