Publications by Colleges and Departments (MSU - Bozeman)
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Item Comparison of Enrichment and Plating Media for Recovery of Virulent Strains of Yersinia enterocolitica from Inoculated Beef Stew(Elsevier BV, 1983-11) Schiemann, D.A.Five plating agar media were evaluated for their ability to recover pure cultures of virulent strains of Yersinia enterocolitica serotypes O:3, O:8 and O:5,27. Cellobiose-arginine-lysine and bismuth sulfite agars were unproductive at 32°C but gave quantitative recovery with 48 h of incubation at 22°C. Adjustment of the pH of bismuth sulfite agar to 7.4 made the medium inhibitory. MacConkey, DHL and cefsulodin-irgasan-novobiocin agars gave quantitative recovery with 24 h of incubation at 32°C. Four preenrichment media incubated at four different temperatures, three selective enrichment media incubated at 22°C, and the five plating media were evaluated for their ability to recovery Y. enterocolitica from beef stew seeded with a background of ten other gram-negative bacteria. None of the plating media was superior for recovery; however, cefsulodin-irgasan-novobiocin agar showed the highest confirmation rate for presumptive colonies. Buffered-sorbitol-bile broth was inferior to richer media such as trypticase soy broth for preenrichment. Of the three selective enrichment media examined, only bile-oxalate-sorbose broth was found useful, especially for strains of serotype O:8 which could be recovered after 1 d of preenrichment and 3 d of selective enrichment at 22°C. Strains of serotypes O:8 and O:3 were recovered when two cells with 107 cells of ten other gram-negative bacteria were added to 10 g of beef stew following preenrichment in trypticase soy broth at 2°C for 7 d and selective enrichment in bile oxalate-sorbose broth at 22°C for 3 to 5 d. Strains of serotype O:5,27 were more difficult to recover even with longer enrichment times. These studies indicated that the most comprehensive enrichment system for recovery of Y. enterocolitica from foods is preenrichment in trypticase soy broth at 22°C for 1 d and 2 to 4°C for 4 to 7 d followed by selective enrichment in bile-oxalate-sorbose broth at 22°C for 3 to 5 d and isolation on cefsulodin-irgasan-novobiocin agar.Item Vegetation Distribution and Production in Rocky Mountain Climates—with Emphasis on Whitebark Pine(International Workshop on Subalpine Stone Pines and Their Environment: the Status of Our Knowledge, 1992) Weaver, T.The distribution and production of vegetation on the altitudinal J gradient (grassland-forest-alpine) was plotted against climatic parameters to evaluate hypothetical controlling factors. (1) Whitebark pine (Pinus albicaulis) is likely excluded from higher zones by a cool growing season or wind-induced drought. It is probably not excluded by low temperatures occurring during its hardening, hard, or dehardening seasons. (2) While the lower physiological limit of whitebark pine is probably set by drought its lower realized limit is directly set by subalpine fir (Abies lasiocarpa) and lodgepole pine (Pinus contorta) competitors and indirectly set by factors that control their distribution. (3) The upper limits for most other dominant species are probably set by growing season temperature. The lower limits are likely set by competition down to the cedar-hemlock (Thuja plicata/Tsuga heterophylla) zone and by drought in drier areas. (4) Production is strongly correlated (r 2 = 0.86) with growing season length (soil thawed season minus dry soil days). Multiplying season length by average temperature did not improve the growing season predictor, perhaps because vegetation at each altitude is especially adapted to temperatures in its zone.Item Climates Where Stone Pines Grow, A Comparison(International Workshop on Subalpine Stone Pines and Their Environment: the Status of Our Knowledge, 1992) Weaver, T.------ Abstract-While stone pine climates are similar adapted to relatively moderate climates may be excluded from, species the ranges of congeners by more severe climates, and species with longer warm-moiBt growing seasons are probably more productive than congeners. Absolute low/summer average/absolute high temperatures for stone pines listed in order of increasing absolute low temperature are Pinus sibirica (-65/13/37 °C), P. pumila (-52.19/36 °C), P. koraiensis (-42/1s1/36 °C), P. albicaulis (-3419/29 °C), and P. cembra (-23/8/27 °C). The Walter drought index shows little stress in stone pine forests despite large differences in summer/winter precipitation: in order of increasing summer rainfall, precipitation is P. albicaulis (102.I 829mm), P. pumila (1421.264mm), P. sibirica (1871245=), P. cembra (3231616mm), P. koraieT18is (3941242mm). Estimated thawed-soil growing season increases from P. albicaulis (4.5mo), throughsP. pumila (4.6mo), P. sibirica (5.5mo), and P. cembra (6.3mo) to P. koraiensis (7.8mo); growing seasons of the first three trees could be shortened by drought.Item Distribution of Exotic Plants in the N. Rocky Mountains by Environmental Type and Disturbance Condition(Montana State Univeristy, 1989-06) Weaver, T.; Gustafson, D.; Lichthardt, J.; Woods, B.This report lists seventy-three exotic species found in a systematic sampling of major environmental zones of the Rocky Mountains between the Canadian border and central Wyoming. For each exotic it states the regional distribution, the environmental types (HTs) it occupies (% constancy), the disturbance conditions (DCs) it occupies (% constancy), and its dominance (in terms of% frequency and% cover) in each cell of the HT x DC matrix. Park managers need to develop policy with respect to legally noxious weeds, forage grasses (eg Phleum pratense, Poa pratensis, Bromus inermis, and Dactylis glomerata), and forage legumes (eg Melilotus and Trifolium spp).Item PLANTS ESTABLISHING IN ROCKY MOUNTAIN ENVIRONMENTS-- a manual for choosing native species for revegetation(Montana State University, 1995) Weaver, T.; Gustafson, D; Lichthardt, JSpecies which have established naturally on a disturbed site in a given environment-- climate and disturbance level (defined below)-- are good candidates for revegetation plantings in that environment. On this basis we recommend native plants (grasses, forbs, and shrubs) for revegetation plantings, if they occur on at least half of the sites sampled in the environmental type and cover at least 1% of the ground there. We also list exotic plants establishing on once disturbed roadside sites; if these plants do not invade native vegetation they might, under some circumstances, be used for revegetation The environmental types considered include dry grasslands (BOGR/STCO and AGSP/BOGR), moist grasslands (FESC/FEID and FEID/AGCA) sagebrush (ARAR/FEID and ARTRVAS/FEID) , warm dry forests (PSME/ SYAL and PSME/PHMA), warm moist forests (POTR/CARU, THPL/OPHO, TSHE/CLUN, ABLA/CLUN), cool forests (ABLA/XETE, ABLA/ARCO, and ABLA/VACC), mountain meadows (FEID/AGCA, listed above) and alpine (DESC/CARX) . In each environment plant performance is contrasted across five disturbance types: continually disturbed types (roadshoulders and the adjacent ditch slope), once disturbed sites (roadcuts with organic matter removed and cleared right-of-way without organic matter removal), and undisturbed late seral sites.Item Cone production in Pinus albicaulis Forests(Inland Mountain West Symposium, 1985-08) Weaver, T.; Forcella, FWhitebark pine cone production was estimated for a 6 to 8 year period in each of 29 stands widespread in.the northern.Rocky Mountains. 1) One-time sampling was possible since the estimate was m2de by multiplying the number of branches perm by an estimate of annual cone production made from counts' of cone lets, mature cones, or cone scars on successively older annual increments of those branches. 2) Average cone production ranged from 0.3 to 3.6 cones·m^-2 ·yr^1 and from 22-270 seeds·m^-2·year^-1 . 3) Regression analysis was used to relate the variance observed to time and place. a) Year-to-year variation in the cone yield of branches, trees, and stands in a region appears to be both internally and externally controlled. Internal control is suggested by the fact that good cone years were usually preceded by poor cone years. While external control is indicated by significant correlations between growth and weather conditions, control is not dominated by the effect of any one factor or any particular developmental stage. b) Although cone production of the average branch varied significantly within 30 percent of the trees and within 48 percent of the stands observed, it did not vary significantly among stands. c) Regressions relating stand cone production to easily measured stand characteristics such as canopy cover, fallen cones, and/or stand size explain no more than 50 percent of the variance among stands.Item Bibliography of Montana vegetation description(1988) Burgeron, P.; Kratz, A.; Weaver, T.; Weidman, N.Listed in alphabetical order by author are 549 references to literature that describes the native vegetation of Montana. This updates the 1965 list of Habeck and Hartley. A keyword subject index is included.Item Evaluating the land: evolving perceptions of landscape in Gallatin Valley settlement, 1864-1918(self-published, 1997-05) O'Neill, MaireThis study investigates how people have viewed the environment and the terrain of the Gallatin Valley through a cross section of time. The period during which the region was settled is explored for its impact on the present palimpsest of the landscape. The choices people made about where to farm and where to site their houses reveals much about their perceptions and attitudes towards the land. What people thought about its potential and its threats are reflected not only in their journals, but in the physical markings they have made in the form of buildings, fences, roads, and irrigation ditches.Item Exotic invasion of timberline vegetation, northern Rocky Mountains, USA(1990) Weaver, T.; Lichthardt, J.; Gustafson, D.Thirty-five exotic species were found in vegetation characteristic of Northern Rocky Mountain timberlines. At least 20 percent were intentionally introduced along road-sides. The diversity of invading exotics declined from subalpine to alpine vegetation. While exotic diversity generally increased with increasing disturbance, severe trampling excluded some species from road-shoulder sites. The exotics of greatest concern to wildland managers are Phleum pratense (timothy) and Poa pratensis (Kentucky bluegraass) because they establish widely, spread vigorously, and usually escape early detection. Control of any exotic should involve its eradication and simultaneous introduction of desirable competitors to minimize reinvasion.Item Seeing whitebark pine in a northern Rocky Mountain (USA) landscape: notes for a field trip(1990) Weaver, T.The changing role of whitebark pine (Pinus albicaulis) along an altitudinal gradient typical of the Northern Rocky Mountains (USA) can be seen from the gondolas at the "Big Sky" resort near Bozeman, MT. Whitebark pine appears mostly as seedlings in the lowest zone (7,500 to 8,500 ft), becomes increasingly important in the canopy between 8,400 and 8,900 ft, assumes climax dominance in the woodland zone (8,900 to 9,300 ft), and maintains that dominance to treeline. On this gradient the mature tree's growth form changes from tall-lyrate, to shorter-spherical, to krummholz. The tree is seral in the lowest zones; frequent fires exclude it from canopies in the lowest zone, while low fire frequency gives it subclimax status higher (8,400 to 8,900 ft) in the zone dominated by subalpine fir (Abies lasiocarpa) at climax. Above 8,900 ft, whitebark dominates woodlands (formed, probably, when subalpine fir is excluded by cold) and krummholz (due, probably, to winter desiccation). Mountain pine beetles (Dendroctonus ponderosae) have killed much of the lodgepole (P. contorta) and whitebark pine in the area, and whitebark groves tend to be ringed with dead trees because the especially vigorous trees at grove edges are most susceptible. Cirque bowls on Lone Mountain demonstrate an inverted timberline at which conifers disappear downward, probably due to spring frosts.