ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

the undisturbed forests. Some research shows that the distance between treated
areas and the undisturbed stand as well as the size of the area treated are both
significant in the interpretation of treatment effects on forest floor arthropods
(Newmann 1971). Others indicate that forests surrounding treated areas are important
in retarding colonization by species of spiders from open habitats, which have to
overcome the barrier as aeronauts, while species of semi-open habitats, occurring
sporadically in surrounding forest stands, have the advantage that they can invade
the area by land (Huhta 1971). A third investigator concluded that spiders move
freely between burned prarie areas and unburned patches, and vice versa, since they
collected more individuals in transects near the periphery of burned areas than in
transects located toward the center (Riechert and Reeder 1972).
The indirect influence of changing the microcl imate depends on the condition of
the stand prior to treatment. The removal of a1 1 or part of either a dense coniferous
stand or of the subsequent residues where the forest floor is heavily shaded will
have more striking effects than the manipulation of a more open-grown stand, where
more light reaches the forest floor and where understory vegetation may be more
abundant. These harvesting and residue practices, particularly clearcutting, disrupts
both diurnal and seasonal fluctuations of many physical factors, principally tempera-
ture, moisture, light intensity, wind, and humidity. Some animal groups, unable to
tolerate the new microcl imate, are at a disadvantage and disappear. Other groups,
perhaps by their abi 1 i ty to reproduce rapid1 y, can survive the environmental change
and may even benefit as a result of treatment.
In another paper in this proceedings, Hungerford (1980) discusses the micrp-
environmental response to harvesting and residue management. He indicates that
following harvesting, on several sites surface conditiws such as radiation load and
temperature have reached lethal levels. In other cases harvesting has aggravated
and created frost pockets. Both temperature extremes, and radiation load and other
factors must certainly influence forest floor arthropods.
At this time we are only able to discuss some general management implicati~ns
of the effects of harvesting and residue management on forest floor fauna, based on
our own research and interpreting related research of others. The full management
implications of these forest insect studies will only be completely realized when
results have been completely integrated with the results of closely-related studies
in other disciplines.
ACKNOWLEDGEMENTS
The following biological technicians--Drew Depuydt, Paul Hengel, and Mrs. Deborah
Olienyk Marino--made important contributions to thTs study beyond the expectations
of their assignments. Drew Depuydt supervised much of the field work, nearly all of
the laboratory processing, as well as the identification and curating of all specimens
collected. Paul Hengel prepared the graphics far the figures, and Deborqh Marino
reviewed, abstracted, and contributed to the interpretations of previous research
cited or discussed in this paper.