Using survey data collected as part of a comprehensive reevaluation of the Vale Rangeland Rehabilitation Project in eastern Oregon, this exploratory study examined variation in attitudes of Bureau of Land Management (BLM) employees toward rangeland environmental conditions. Almost one-half of the BLM employees surveyed believed the loss of streamside vegetation (48%) and streambank erosion (42%) were widespread problems on Vale rangelands. Approximately a quarter of the respondents believed rangeland soil loss (24%) and overgrazing (26%) were problems, while only a tenth believed water pollution (10%) was a problem on many or most areas. A composite scale of these attitude toward environmental conditions on rangelands was developed and assessed. The composite scale was regressed on respondents' regional affiliation, length of service, and ideological attitudes towards government role in natural resource management. In contrast to findings from studies for USFS employees, attitudes toward range environmental conditions were not determined by regional affiliation or length of service (P > 0.05). Rather, BLM employee attitudes toward range environmental conditions were found to vary by the interaction of length of service in the agency and attitude toward government's role in regulating water quality (P < 0.05) and managing livestock grazing (P < 0.01). As length of service increases, core beliefs, professional norms, or client constituencies may not polarize employee attitudes but rather moderate them over time. The accumulation of environmental knowledge may also tend to influence environmental attitudes so that ideological attitudes may have a weaker effect as time passes and expertise expands.

Consumption of tall larkspur (Delphinium barbeyi L. Huth.) can be fatal to cattle grazing mountain rangeland during summer. Tall larkspur contains many alkaloids, but virtually all the toxicity is caused by methyl succidimido anthranoyl lycoctonine-type (MSAL) diterpenoid alkaloids. We measured the concentration of MSAL alkaloids (% of dry matter) in tall larkspur in various phenological stages during 1990, 1991, and 1992 near Yampa, Colorado. The site represented tall larkspur-infested rangelands on the western slope of the Rocky Mountains. Toxic alkaloid concentrations were greatest (0.4 to 0.6%) early in the growing season (bud stage). Toxic alkaloid concentrations were generally static during the flower and pod stages, or increased during the pod stage. Immature leaves had greater MSAL alkaloid concentrations early in the growing season compared to flowering parts. Alkaloid concentrations in pods were greater than in leaves (P<0.05; pod stage), as pod concentrations increased to 0.4% late in the growing season. In 2 of 3 years, plant parts did not differ in MSAL alkaloid concentrations, although weather conditions differed each year. Concentrations of toxic alkaloids did not seem to influence amounts of tall larkspur consumed by grazing cattle on the same sampling dates. Many livestock producers defer grazing of tall larkspur ranges until the plant is in the pod stage because of a general belief that toxicity is greatly reduced. Our results suggest that grazing tall larkspur ranges during the pod stage may exacerbate cattle losses if MSAL alkaloid concentrations do not decrease, yet consumption by cattle increases.

Summative equations to predict digestibility of tropical browse species for cattle were tested by comparison to in vitro digestibility. Four equations were used for the comparison: first the 2 Van Soest equations, 1 using sulfuric acid lignin and the other using permanganate lignin, neither of which have a correction for tannins. And second, the 2 Horvath equations, each using 1 of the 2 above mentioned lignin values and both include a value for tannin content. The Van Soest equation using permanganate lignin and the Horvath equation using sulfuric acid lignin predicted the in vitro digestibilities of the leaf species quite well (r = 0.89 for both). The same Horvath equation predicted the digestibility of the high tannin species better than the Van Soest equation (r = 0.93 versus 0.84). For initial evaluation and ranking of browse species suitable for future research efforts, either equation suitable.

This research determined the preliminary response of sandhills prairie to spring and summer prescribed burns, and their interaction with bison (Bison bison) grazing. Changes in species composition and standing crop were determined for paired (caged/uncaged) plots established in burned and unburned areas during the 1991 and 1992 growing seasons. End of season standing crop of both rhizomatous grasses and bunchgrasses was increased by spring burning on sands range sites. Summer burning did not affect rhizomatous grass standing crop, but dramatically reduced bunchgrass standing crop. On burned areas, bison grazing reduced bunchgrass standing crop by 56%, while reducing rhizomatous grass standing crop by only 18%. Forbs generally appeared unaffected by bison grazing and were affected variously by burning. The current bunchgrass composition of Nebraska Sandhills prairie appears dependent on fire exclusion. With fire, a replacement of bunchgrass with rhizomatous grasses may increase available forage, but also increase the risk of wind erosion, particularly on choppy sands range sites.

Information is limited on the influence of range condition on cattle diets in the Chihuahuan desert. Botanical composition of cattle diets on Chihuahuan desert ranges in excellent and good condition was studied by microhistological analysis. Cattle feces were analyzed seasonally from fall 1991 through fall 1992. Excellent condition and good condition ranges supported 86% and 72% of the climax vegetation, respectively. Key species in cattle diets on the excellent condition range were black grama (Bouteloua eripoda Torr.) and threeawns (Aristida spp.). On the good condition range the key species were dropseeds (Sporobolus spp.), threeawns and black grama. Total grass and black grama content of cattle diets were greater on the excellent condition range. Seasonal trends occurred in cattle diets on good condition but not on excellent condition range. Low availability of forbs and shrubs explained the high diets similarities among seasons on the excellent condition range. Cattle on good condition range readily used forbs and shrubs when green grass was unavailable. Nitrogen and phosphorus analyses of fecal samples indicated diets were nutritionally superior on the good compared to the excellent condition range. Our research and other studies show consumption of forbs and shrubs permits cattle to maximize their nutritional welfare when grasses are dormant. The excellent condition range in our study had a different(P<0.05) mean grass standing crop (999 kg/ha) across periods compared to on the good condition range (659 kg/ha). Based on our research and other studies excellent condition Chihuahuan desert range maximizes forage quantity for cattle but good condition range appears better from a nutritional standpoint in the spring and early summer. Our research and other studies indicate Chihuahuan desert ranges dominated by black grama are most effectively used in winter while ranges with a high dropseed component are best suited for use in summer and early fall.

Smooth bromegrass (Bromus inermis Leys.), orchardgrass (Dactylis glomerata L.), alsike clover (Trifolium hybridum L.), and a mixture by mass of 40% orchardgrass, 40% alsike clover, and 20% white clover (Trifolium repens L.), were sown at 0.5, 1.5, 3.0, 6.0, and 12.0 kg/ha on a forest clear-cut in the southern interior of British Columbia. The seeding treatments were monitored for 3 growing seasons following planting to determine their influence on the growth, survival and damage of planted one-year old lodgepole pine (Pinus contorta var. latifolia Engelm.) seedlings. Competing vegetation reduced lodgepole pine diameter by up to 38% (P < 0.004) and heights by up to 30% (P < 0.005). Lodgepole pine basal diameters (P < 0.002), height (P < 0.02) and survival (P < 0.03) decreased linearly with increasing forage seeding rate. Lodgepole pines planted with smooth bromegrass had up to 59% larger (P < 0.01) diameters and were up to 33% taller (P < 0.06) than those planted with orchardgrass at equal seeding rates by mass. Lodgepole pine cumulative mortality was 2 to 5 times greater (P < 0.0001) on plots sown to alsike clover compared to plots sown with smooth bromegrass or orchardgrass. Rodent damage peaked between the first and second growing seasons at 24% of the lodgepole pine seedlings; rodent damage was similar (P > 0.05) among the treatments and controls, and conifer survival was independent (P > 0.05) of rodent damage.

Changes in woodland vegetation integrate the consequences of livestock grazing intensity, the alteration of fire regimes, and possible climate alterution, as well as other factors. Quantitative measurements of these changes, if taken over sufficient intervals, can allow evaluation of conservation management strategies. In 1933, vegetation along a 37-km transect in southern Pine Valley, Utah was described from circular 19-m2 plots located every 42 m. The major intermediate management treatment has been reduction of grazing pressure by introduced animals, although a fraction of the area was chained and burned in 1977. During a period climatically and phenologically similar to the original study, we reexamined representative segments of this transect by a more detailed updating of the original "square-foot-density" method. Significantly greater shrub and perennial grass covers (more than threefold increases) were found in 1989, even where overall dominance is still by pinyon-juniper [Pinus monophylla (Torrey & Fremont) and Juniperus osteosperma (Torrey) Little]. This change is more obvious on steeper slopes away from roads and water, where both human and livestock disturbances would be expected to be minimized. Except in the chained portion, the observed shifts in dominance/diversity are contrary to widely accepted expectations.