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Item Effects of grazing after wildfire on soil health in eastern Montana(Montana State University - Bozeman, College of Agriculture, 2021) Hanson, Joshua Todd; Chairperson, Graduate Committee: Clayton B. Marlow; Clayton B. Marlow, Kurt O. Reinhart, Lance T. Vermeire and Sam A. Wyffels were co-authors of the article, 'Effects of grazing after wildfire on indicators of soil health in eastern Montana' submitted to the journal 'Fire ecology' which is contained within this thesis.Rangelands are resilient to grazing and fire. However, the resilience of rangelands may be degraded by livestock grazing too soon after wildfire. Due to the growing interest in soil health and its link to sustainable grazing, following a large wildfire (109,346 ha, Lodgepole complex in 2017) we tested the effect of grazing (grazed verses no grazing) on three indicators of soil health in ponderosa pine savvanas of the northern Great Plains. We measured indicators of soil hydrologic function (i.e., soil hydraulic conductivity), properties related to nutrient cycling (i.e., soil organic matter, plant available nutrients, pH), and soil structure (i.e., aggregate stability) in 2019 and 2020. Grazing occurred two out of three years following the fire. Most indicators of soil health were not appreciably affected by grazing post-fire. However, we detected a marginally significant negative effect of grazing on soil organic matter. Specifically, soil organic matter was 7% greater in ungrazed than grazed areas. No other grazing treatment effects were detected. Several soil health metrics varied between sampling years. Our results suggest that grazing(two out of the three years) following fire is unlikely to negatively affect many indicators of soil health of ponderosa pine savannas in the northern Great Plains. The increased organic matter observed by resting did not have an appreciable impact on the other soil health metrics. These findings suggest that soil health indicators are relatively resilient to grazing after wildfire and have implications for grazing policy post-fire.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 The effects of fire and grazing in the northern mixed-grass prairie : implications from the Pautre wildfire(Montana State University - Bozeman, College of Agriculture, 2016) Gates, Emily Ann; Chairperson, Graduate Committee: Clayton B. Marlow; Lance T. Vermeire, Clayton B. Marlow and Richard C. Waterman were co-authors of the article, 'Reconsidering rest following fire: northern mixed-grass prairie is resilient to spring wildfire and resistant to moderate post-fire grazing' submitted to the journal 'Rangeland ecology and management' which is contained within this thesis.; Lance T. Vermeire, Clayton B. Marlow and Richard C. Waterman were co-authors of the article, 'Season of post-fire defoliation: effects on biomass, community composition and ground cover' submitted to the journal 'Rangeland ecology and management' which is contained within this thesis.; Lance T. Vermeire, Clayton B. Marlow and Richard C. Waterman were co-authors of the article, 'Forage fiber digestibility dynamics in the northern mixed-grass prairie following spring wildfire' submitted to the journal 'Rangeland ecology and management' which is contained within this thesis.Current federal recommendations pertaining to the management of post-fire grazing on rangelands interrupts historic disturbance regimes of the North American prairies by indicating that fire and grazing should be separated by at least two growing seasons. In contrast, some scholars suggest that North American prairie evolved under a tight linkage of fire and proximate post-fire grazing and should be well adapted to these combined disturbances. The Pautre wildfire of April 2013 provided an opportunity to test the effects of post-fire grazing in the northern mixed-grass prairie. One grazing allotment, burned in its entirety, and three burned and nonburned sites spanning a north-south gradient of the fire perimeter were selected as study locations. The effects of grazing versus rest, defoliation during the first spring, summer, or fall following the fire on burned and nonburned sites and the effects of fire on forage fiber digestibility were tested. Sites grazed during the first two growing seasons following the fire were found to recover similarly to sites rested during that same time. In addition, defoliation during any season following the fire produced no negative effects when compared to nondefoliation. Increases in forage fiber digestibility peaked shortly after fire and were short-lived, diminishing by the following year. These results lend support to the theory that fire and grazing were historically linked disturbances throughout the evolution of the North American prairies, indicating that the federal recommendation of rest is unnecessary in at least the northern mixed-grass prairie ecoregion. Historic, evolutionary patterns of disturbances, such as fire and grazing, may be useful in determining the most appropriate post-fire management regimes for specific ecoregions.Item The effects of prescribed burning on deer and elk habitat parameters in Montana's Missouri River Breaks(Montana State University - Bozeman, College of Agriculture, 2004) Wood, Christopher Karl; Chairperson, Graduate Committee: Clayton B. Marlow.Fire suppression has been practiced along the Missouri River Breaks for decades and has led to a series of resource issues. Among these issues was a build up of dangerous fuel loads and restricted foraging areas for livestock and big game. Because the Missouri Breaks are an important wintering area for mule deer ((Odocoileus hemionus hemionus Rafinesque) and elk (Cervus elaphus nelsoni Bailey), the Bureau of Land Management (BLM) wanted to know how a series of prescribed burns in late May and early June of 2002 would affect habitat. The prescribed burns left a mosaic of unburned, scorched, and heavily burned landscape across the study site. There was concern that the reductions in hiding and thermal cover and decreased browse availability would have adverse impacts on the mule deer and elk populations. To evaluate the possible impacts of the prescribed fire on deer and elk populations use of unburned, scorched and heavily burned areas were compared using pellet group counts and winter browsing pressures. Thermal and hiding cover measurements were taken to quantify fire intensity effects on cover loss. Forb and grass rejuvenation was monitored one and two years after the burn to measure the impacts to the forage base. Thermal cover did not differ significantly (P>0.10) between unburned, scorched, and heavily burned areas. Scorched and heavily burned areas had significantly less (P<0.10) hiding cover than unburned areas. While grass did not differ significantly among the treatments, forbs were greater in the second year after the burn in scorched and heavily burned areas. Pellet groups counts indicate that mule deer used all burn intensities and showed no indication of preference or avoidance of various cover levels or forage availability. Elk use of the study site was too minimal to analyze. There was no significant difference (P>0.10) between browsing pressures in meadows of burned and unburned areas, suggesting that deer did not select browsing areas based on adjacent cover levels. There were however, were significant differences (P<0.01) among browsing pressures of the three browse species. The use of prescribed fire as a management tool without adversely effecting deer and elk populations looks promising. Prescribed fire can be used to improve habitat for mule deer and elk. The prescribed fire maintained sufficient thermal and hiding cover levels while increasing total forb cover including many important species considered important for mule deer.