Theses and Dissertations at Montana State University (MSU)
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Item Evaluating grazing and defoliation effects on ponderosa pine grassland following the lodgepole complex wildfire(Montana State University - Bozeman, College of Agriculture, 2020) Williams, Amanda Rae; Chairperson, Graduate Committee: Clayton B. Marlow; Lance T. Vermeire, Richard C. Waterman and Clayton B. Marlow were co-authors of the article, 'Evaluating grazing effects on ponderosa pine grassland following the lodgepole complex wildfire' submitted to the journal 'Rangeland ecology and management' which is contained within this thesis.; Lance T. Vermeire, Richard C. Waterman, Clayton B. Marlow were co-authors of the article, 'Season of defoliation effects on ponderosa pine grassland following the lodgepole complex wildfire' submitted to the journal 'Rangeland ecology and management' which is contained within this thesis.Previous research indicated rangelands need rest from grazing after fire, while others show grazing the first year following fire has no negative effects on the plant community. This caused uncertainty around post-fire grazing management. In July 2017, the Lodgepole Complex fire burned ponderosa pine grasslands of the northern Great Plains, including areas burned in 2003 for fuels mitigation. We examined effects of post-fire grazing and season of defoliation. For the grazing study we wanted to determine 1) plant community response to grazing or rest the first growing season after fire in ponderosa pine grassland communities, and 2) whether prescribed fire alters plant community response to subsequent wildfire. For the season of defoliation study we wanted to determine 1) timing of defoliation effects on the plant community one growing season after fire and 2) whether defoliation effects are altered by prescribed fire preceding the fire. Eight exclosures (25 x 15 m) were built, 4 reburned sites and 4 wildfire sites. A non-grazed (15 x 10 m) section inside each exclosure was paired with a grazed section outside the exclosure. Plots (5 x 10 m) were mowed in the exclosure to 10 cm in June, July, or August, or not mowed during 2018. In 2019, biomass samples were clipped at peak production, with species composition and diversity measured by point-intercept transects. We observed a trend for reduced cool-season grasses (P =0.0675) and annual grasses (P =0.0071) if defoliated earlier; a trend for reduced forbs (P =0.0699) if defoliated later; and reduced total current-year biomass (P =0.0362) if defoliated. Functional group composition was not changed, but some individual species were shifted due to fire history. The grazing study only showed a trend for greater old dead biomass on non-grazed sites (P = 0.0600), higher composition of forbs on reburn sites (P = 0.0324), and a trend for a higher composition of Psoralidium tenuiflorum (Pursh) Rydb. on reburn sites (P = 0.0559). Results indicate mowing the first year following fire shifts the plant community, but the community is resistant to post-fire grazing. Prescribed fire 14 years before wildfire had small impacts on community composition.Item Associations of broad scale vegetation characteristics and abundances, nest densities, and nest survival of mixed-grass prairie songbirds in northern Montana(Montana State University - Bozeman, College of Agriculture, 2019) Pulliam, John Patrick; Chairperson, Graduate Committee: Lance McNewGrassland bird populations are declining faster than any other avian guild. In northern Montana, four species are experiencing severe population declines: Baird's sparrow (Centronyx bairdii), chestnut-collared longspur (Calcarius ornatus), McCown's longspur (Rynchophanes mccownii), and Sprague's pipit (Anthus spragueii). In 2017 and 2018, I evaluated abundance, nest density and nest survival of these species in relation to local vegetative conditions with the goal of identifying important breeding season vegetation conditions to inform management. I conducted fixed-radius point-counts at 100 sites to estimate local abundance, rope drag surveys to estimate nest density, nest monitoring to estimate nest survival, and vegetation surveys to estimate vegetation structure and composition across grassland habitats in Phillips County, MT. Point-counts and rope drag surveys were carried out with replicated visits to allow estimation of species-specific detection probabilities. Vegetation conditions were measured at the plot level (9-ha) to provide information at scales relevant for land managers. The abundance of Baird's sparrows was positively associated with residual grass cover and litter cover. Chestnut-collared longspur abundance was negatively associated with residual grass, exotic grass, and shrub cover and had a quadratic relationship with biomass. Plot-level abundance of McCown's longspurs was negatively associated with both shrub cover and biomass. Sprague's pipit abundance declined with exotic grass cover and exhibited a quadratic relationship with biomass. Limited sample size only allowed inference of nest density and nest survival for chestnut-collared longspurs. Nest density was negatively associated with plot scale exotic grass cover, biomass, and slope. I did not find support for any vegetation covariates on nest survival for chestnut-collared longspurs. These results provide some guidance for landscape managers interested in improving habitat for these species. The contrasting results among species, however, emphasize the need for heterogeneity in vegetation structure and composition. The disconnect between relevant covariates for nest density and nest survival suggest possible maladaptation for chestnut-collared longspurs. This result suggests that an index of productivity for this species that does not include both nest density and nest survival may produce erroneous results.Item Elk effects on sagebrush-grassland after fire on Yellowstone's Northern Range(Montana State University - Bozeman, College of Agriculture, 2001) Rens, Reyer JanItem Effects of black-tailed prairie dogs on the mixed-grass prairie in Montana(Montana State University - Bozeman, College of Agriculture, 2002) Johnson, Carolyn MarieItem Predicting dominant species on grasslands at the National Bison Range, Moiese, Montana(Montana State University - Bozeman, College of Agriculture, 2014) Garcia Neto, Narciso; Chairperson, Graduate Committee: Clayton B. MarlowUnder ecologically sustainable conditions, a landscape should retain representative climax vegetation. Thus, a method to predict the climax species component of a functioning vegetation community is an important tool for restoration projects. Based on descriptions of the Palouse Prairie grassland the National Bison Range managers selected bluebunch wheatgrass, Idaho fescue, and rough fescue as target species for management and restoration objectives. An indicator called Relative Effective Annual Precipitation (REAP) was created by Montana Natural Conservation Service (NRCS) to express the amount of water available to the plants, at a specific location, taking into account precipitation, slope and aspect, and soil properties. Using Geographic Information System (GIS) and REAP as the predictor variable, a map to predict the occurrence of species within grassland communities was developed to guide restoration and management efforts on the USFWS National Bison Range. REAP values were calculated for sample sites from three earlier rangeland assessments and related to actual field measures of the target species. Classes of REAP intervals were defined to bracket the range in value for each species. Classes were also created for target groups (bluebunch and fescue) sorted by genus. REAP values for sites dominated by bluebunch wheatgrass were significantly different from values for sites dominated by Idaho fescue and rough fescue (P < 0.0001). However, there were no statistical differences between REAP values for Idaho fescue and rough fescue (P=0.989).The mean probability of the REAP model to accurately predict the occurrence individual target species was 0.55 and for the target group was 0.64. NBR and should be dominated by grasses, but there were patches of conifer forest. The values of REAP related to the forest patches were compared against REAP values for grassland areas to learn if the model could differentiate between the two major cover classes. The REAP values for the forest patches were higher than values predicted for grasslands (P=0.0026). So, prediction of areas dominated by grasslands was different from forest sites. However, the discrimination between Idaho and rough fescue was not successful.Item Patterns of gray rubber rabbitbrush occurrence in burned sagebrush-grasslands, Missouri River Breaks, Montana(Montana State University - Bozeman, College of Agriculture, 2012) Owings, Glenn Curtiss; Chairperson, Graduate Committee: Clayton B. Marlow.Sagebrush-grasslands represent a large portion of the plant communities within the arid plains of the western United States. Grasses, forbs, and shrubs exist as subdominants to sagebrush that vary in density according to disturbances such as fire, wind, and defoliation. Fire is an important modifier of succession in sagebrush-grasslands, and shrub response to fire may be altered by browsing. The fire response of gray rubber rabbitbrush (Chrysothamnus nauseosus (Pallas ex Pursh) Nesom & Baird ssp. nauseosus) has not been well documented. Furthermore, it is heavily browsed in central and northeastern Montana and is an important winter forage for ungulates. This study investigated how it responds to fire and browsing. Fifteen sites (9 burned and 6 adjacent non-burned) in the Missouri River Breaks, Montana were analyzed to investigate relationships between shrub density, time since fire, shrub age, and browsing level (n=15). Density was counted in one 625m ² macroplot per site. Gray rubber rabbitbrush age (seedling, juvenile, mature) was estimated using basal stem diameter. A qualitative browsing level was assigned based on growth form characteristics (low, moderate, high). Time since fire was not significantly correlated with differences in gray rubber rabbitbrush (P=0.701, R-sq=0.00%) or sagebrush (P=0.391, R-sq=0.00%) density as a percentage of the shrub community (n=9). As a percentage of the shrub community, big sagebrush density at a site was a good indicator of gray rubber rabbitbrush density (n=15, P<.001, R-sq=68.45). Rabbitbrush decreases within the shrub community as sagebrush dominance increases. Gray rubber rabbitbrush composed a higher percentage of the shrub community in burned than non-burned sites (n=6, P=0.005). Big sagebrush composed a higher percentage of the shrub community in non-burned sites than burned sites (n=6, P=0.001). The percentage of gray rubber rabbitbrush shrubs in the "high" browse class was not a statistically significant predictor of density as a proportion of the shrub community (n=13, P-value=0.161, R-sq=9.49%). Results indicate that gray rubber rabbitbrush responds to fire by increasing shortly after disturbance, falling out of the community at some threshold as sagebrush is re-established. Browsing did not affect the ability of gray rubber rabbitbrush to dominate for a period after fire.