Treesearch

Peak season multi-species cover of vegetation and burrow mound density were estimated for 3 years along a transect that ran from the geometric center of a black-tailed prairie dog (Cynomys ludovicianus) colony, to its edge. The forb dominated core of the colony expanded 25 m in radius during the study, while plant composition changed dramatically in a small (2=0.72, P<0.001), occurred only after shortgrasses were reduced below 75% cover. The density of burrow mounds was positively correlated to compositional change (r=0.58; P<0.01). We observed that burrow mounds provided early sites for...

Immediate and long-term effects of 3 rodenticide treatments on nontarget invertebrates were evaluated on prairie dog colonies. Immediate impacts indicated zinc phosphide reduced ants, strychnine alone reduced wolf spiders, and prebaited strychnine had no impacts. Long-term changes showed increases in wolf spiders and ground beetles and densities were contributed to biotic and abiotic habitat alterations due to lack of prairie dog activities. Among comparisons for efficacy, zinc phosphide was more efficacious at immediately reducing ant densities than either strychnine treatment; long term...

Last summer, I finally got my chance to float the Colorado River through the Grand Canyon, one of the world’s premier adventure trips. For 18 days and 280 miles, my group floated through some of the most spectacular scenery imaginable, spacing our days with hikes through slickrock alcoves, along terraced pools of blue-green water, to waterfalls plunging out of holes on 500-foot cliffs and to Anasazi ruins perched high in those cliffs. Nights were spent on expansive beaches under moonlit skies.

This screening procedure is intended to help wilderness managers conduct "adverse impact determinations" as part of Prevention of Significant Deterioration (PSD) applications for sources that emit air pollutants that might impact Class I wildernesses. The process provides an initial estimate of susceptibility to critical loadings for sulfur, nitrogen, and ozone. It also provides a basis for requesting necessary additional information where potential adverse impacts are identified.

The issue of domestic livestock grazing will become more controversial as wilderness areas managed by the Bureau of Land Management are added to the system. Many of these areas are likely to have little recreational use, leaving livestock grazing as the most serious potential threat to wilderness values. My intent is to point out the importance of problems related to livestock in wilderness and to suggest some particularly critical research needs. I will discuss recreational and domestic livestock separately, in each case giving a brief overview of existing knowledge followed by my view of...

Presents the expected reduction in surface erosion from selected treatments applied to forest road traveledways, cutslopes, fillslopes, and ditches. Estimated erosion reduction is expressed as functions of ground cover, slope gradient, and soil properties whenever possible. A procedure is provided to select rock riprap size for protection of the road ditch.

Investigations on the allelopathic potential of bracken fern in northern Idaho were conducted to gain an understanding of the mechanism(s) associated with regeneration failures. Average growth and green top weight of conifers planted in potting soil were about 1.8 and 1.6 times greater than those planted in soil from bracken glades. Greenhouse tests showed little reduction in germination of conifer and shrub seeds on soil from bracken glades. Further germination tests of conifer seeds in bracken glades showed that seeds germinated but died before shedding their seedcoats. The percentage of...

This paper provides an analysis of the resource interactions implied by the forest planning alternatives for the National Forest System. It is concluded that current levels of production and environmental conditions can be maintained at current cost levels, and that even a modest scenario for future production increases will imply a substantial increase in cost.

The National Forest System Resource Interactions Model is an upper level linear programming model developed to aid in the analysis of multiresource interactions for the 1989 RP A National Assessment. This report documents the development and structure of this linear programming model, emphasizing its multilevel nature and the data requirements for such an approach. The resolution of data deficiencies, a major problem in applying such a multilevel optimization approach, also is examined.

These proceedings consist of more than 40 presented papers on damage caused by many different animals. Panel presentations that followed two special sessions - one on prairie dogs and related small mammals and another on ways to enhance waterfowl production - are also included. In addition to information on mechanical and chemical control methods, the ecosystem processes involved are considered.