Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
Browse
8 results
Search Results
Item Effects of time, cultivar, and storage environment on winter squash in semiarid Montana(Montana State University - Bozeman, College of Agriculture, 2023) Sheild, Victoria Marie; Chairperson, Graduate Committee: Mac BurgessWinter squash can be stored for months after harvest while taste, texture, and color attributes improve. The potential for producers to attain greater storage longevity and produce better squash would benefit farmers, consumers, and economies. Due to variation in local climates and the respective vendors' needs, understanding how to control a storage environment can be challenging. This research looks at how storage environment and storage period affect biochemical and physical attributes of ten varieties of winter squash in a semiarid climate. The varieties include three Cucurbita pepo, one Cucurbita moschata, one Cucurbita maxima x moschata hybrid, and five Cucurbita maxima cultivars. Two storage environments were used for analysis. One was located indoors and cooled to 53 degrees F while the other was built into an existing barn with a heating unit and insulation to keep the temperature above freezing. A total of 240 winter squash were placed in each storage space. A completely randomized design was used to assign categorical treatments of storage time to each winter squash, with six levels of treatment being implemented. Each variety of squash (n=4) was analyzed monthly in each storage environment for changes in soluble solids, dry matter, starch content, interior color and exterior color (using CIELAB color values L*, a*, b*), and mass. The temperature and relative humidity of each storage environment were also monitored and recorded hourly during the same period. Cultivar was always the most significant factor. There was no simple effect of the storage environment on dry matter, soluble solids, starch content, or mass. There was a strong significant interaction observed between time and cultivar for each response variable, which shows us that the type of squash and how long it should be stored for are important when discussing quality. Storage did have a significant effect on the a* value of interior color, which is an indicator of quality and nutritional value. The biochemical and physical attributes of each cultivar analyzed varied greatly in its response to the amount of time in storage which in turn influences the taste, texture, and sensory quality of each cultivar uniquely.Item Dormant season grazing of northern mixed grass prairies: effect of supplementation and winter environmental conditions on beef cattle grazing behavior, residual vegetation conditions and variation in supplement intake(Montana State University - Bozeman, College of Agriculture, 2019) Wyffels, Samuel Aaron; Chairperson, Graduate Committee: Lance McNew; Janice G. P. Bowman (co-chair); Lance B. McNew, Janice G.P. Bowman, Mark K. Petersen, Darrin L. Boss and Bok F. Sowell were co-authors of the article, 'Dormant season grazing of northern mixed grass prairies: the effect of supplementation strategies on heifer resource utilization and vegetation use' submitted to the journal 'Rangeland ecology & management' which is contained within this thesis.; Lance B. McNew, Janice G.P. Bowman, Mark K. Petersen, Darrin L. Boss and Bok F. Sowel were co-authors of the article, 'Dormant season grazing on northern mixed grass prairie agroecosystems: does protein supplementation and individual animal variation impact beef cattle resource use, vegetation and residual cover for wildlife' submitted to the journal 'Rangeland ecology & management' which is contained within this thesis.; Lance B. McNew, Janice G.P. Bowman, Mark K. Petersen, Darrin L. Boss and Bok F. Sowell were co-authors of the article, 'The influence of age and environmental conditions on supplement intake by beef cattle winter grazing a northern mixed-grass rangeland in Montana' submitted to the journal 'Rangeland ecology & management' which is contained within this thesis.Dormant season grazing reduces reliance on harvested feeds, but typically requires protein supplementation to maintain animal performance and vegetation utilization across the landscape. However, information relating supplementation strategies and supplement intake behavior to individual grazing behavior and resource utilization on dormant forage is lacking. Thus, the intent of this research is to examine cattle resource utilization, supplement intake behavior, residual cover of vegetation and utilization on rangelands grazed during the dormant season. One hundred weaned heifer calves were randomly selected and placed into one of two supplementation treatments in each of 2 years (50 heifers/treatment/year); one receiving a free access 62% crude protein self-fed mineral/protein concentrate, and the other receiving a daily hand-fed 20% crude protein cake while grazing December through March. Additionally, a commercial herd of 300 bred cows ranging in age from 1- to 12-yr-old were provided a 30% crude protein self-fed supplement with 25% salt to limit intake in a SmartFeed Pro self-feeder system to measure individual animal supplement intake from November to January in each of 2 years. In both grazing trials, transects were randomly located within each pasture for measuring vegetation composition, production and quality, canopy cover and visual obstruction readings pre and post grazing. Grazing locations were monitored for individuals with Global Positioning System collars containing head position sensors that record daily space use and location of grazing activities. Data sets were used to quantify space use with generalized linear models to assess cattle resource utilization and supplementation behavior. Cattle provided the hand-fed cake selected grazing location near supplement delivery sites and spent less time grazing per day than self-fed supplemented cattle. Substantial amounts of herd-level variability in both studies suggests individual attributes are major drivers in cattle resource use. Supplement treatment and grazing intensity had little impact on residual vegetation conditions, however, the timing of grazing and year did affect the response of residual vegetation to grazing. Younger cattle consumed more supplement with less variability than older aged cattle. This research provides multidimensional insight to stakeholders concerning grazing behavior and the ecological impacts of late season use on Montana rangelands.Item Vehicles, grooming, and other factors affecting snowroad longevity in Yellowstone National Park(Montana State University - Bozeman, College of Engineering, 2018) Nelson, Molly McKellar; Chairperson, Graduate Committee: Edward E. AdamsIn winter, the National Park Service (NPS) at Yellowstone grooms snow that builds up on the park roads, making 'snowroads' passable by snowmobiles and snowcoaches. The NPS has recently allowed experimental snowcoaches on low-pressure tires (LPTs) in addition to traditional tracks. As they consider a permanent policy on these LPTS, they want to understand these vehicles' impacts on snowroads compared with those of traditional tracked vehicles and snowmobiles. They also want to know how to optimize other operations (e.g., grooming) to maintain quality roads that support safe travel through the park. This two-year field study investigated the snowroad quality in the park and factors influencing this quality. The approach involved data collection on both parkwide road conditions and individual vehicle passes. Both controllable and non-controllable factors were considered to provide information on their relative influence. Parkwide road quality analysis involved collecting GPS data on grooming activity, weather data from existing stations, road depth through radar measurements, traffic counts from motion-sensor cameras, hardness data, and snow sample analysis. The vehicle-by-vehicle impact study involved both subsurface and surface measurements in the road. Load cells, accelerometers, a high-speed, high-definition camera, a penetrometer, and a 'profilometer' provided measurements. Data analysis combined with existing literature provided insights into best practices for the NPS. Parkwide, snowroads harden throughout the season, with temperatures and traffic load being contributing factors. Grooming results in a harder road if snow disaggregation is followed by compaction, and with a longer set time between grooming and traffic. Individual vehicles' impacts are driven by surface interaction rather than motion at depth in the snowroad. On hard, groomed snowroads, both tracked and LPT snowcoaches can form ruts, but tracked vehicles continue to dig ruts deeper whereas LPT coaches' ruts level out and stop deepening with subsequent passes. This seems to be because LPTs form ruts primarily through compaction and tracked vehicles through snow displacement. Reduced tire pressures reduce rut formation and can harden the road. Results from this study demonstrate that LPT coaches should not be disallowed from Yellowstone based on road impacts. Other results will inform NPS operations to optimize grooming practices.Item A Yellowstone snowroad rutting investigation: a comparison of tracks vs. tires and other contributing factors(Montana State University - Bozeman, College of Engineering, 2018) Phipps, Ry Edward; Chairperson, Graduate Committee: Daniel MillerYellowstone National Park (YNP) has been experiencing more snowroad rutting in the last ten years. Additionally, YNP has recently (winter 2013 -2014) been experimenting with permitting large low-pressure tire vehicles to operate on the parks' snowroads. To gain a better understanding of snowroad degradation, YNP employed a team of snow scientists from Montana State University. In the winter of 2015, a large scale, two year, snowroad rutting study began in YNP. Parameters pertaining to snowroad strength and the difference in impact to the snowroads between tracked and wheeled vehicles were examined. This thesis in addition to Nelson's (2018) thesis produce a detailed overview of controllable and uncontrollable factors of maintaining and measuring impacts to the snowroads of Yellowstone National Park. Instruments were developed to collect data in the field and in the Sub-Zero Lab at Montana State University. These instruments allowed researchers to quantify crucial differences between vehicle types and the behaviors associated with them. Once data was collected, the data was post-processed in various ways to analyze trends pertaining to snowroad strength and degradation. With the data processed and analyzed, the profilometer and hardness data proved to be the most informative on snowroad degradation tendencies, however, the other instruments helped reinforce conclusions made with the hardness and profilometer data. The process of taking subsurface measurements on vehicle pass-bys, allowed researchers to confirm that rutting is most closely tied to vehicle-surface interactions (~ top 10 cms). It was determined that wheeled and tracked coaches can both cause ruts but by different processes. Wheeled vehicles are primarily causing ruts through compaction whereas tracked vehicles primarily cause ruts through a process of snow displacement. Ruts form from wheeled coaches but after subsequent passes the cross-sectional area of the rut tends to level off, especially when inflation pressure is decreased. While tracked vehicles' ruts continue to grow in size after subsequent passes. Additionally, snowroad hardness was affected differently between tracks and tires. Tracks and tires at higher pressures (> or = 62 kPa) tended to more often soften the snowroad, whereas lower pressure tires (< 62 kPa) tended to harden the snowroad.Item Yellowstone National Park & the winter use debate: community resilience and tourism impacts in the gateway community of West Yellowstone, MT(Montana State University - Bozeman, College of Letters & Science, 2016) Hamming, Carl Alan; Chairperson, Graduate Committee: Julia Hobson Haggerty; Julia H. Haggerty, Ray Rasker and William Wyckoff were co-authors of the article, 'Community resilience in a tourist town' submitted to the journal 'Annals of Tourism Research' which is contained within this thesis.This study explores the socioeconomic impacts of the National Park Service's winter use management of Yellowstone National Park on the gateway community of West Yellowstone, Montana. As a highly specialized, tourism-dependent gateway community, the National Park Service's management decisions that affect park visitation also impact the economic viability of West Yellowstone. Previously, scholars have documented the challenges presented by tourism economies and 'resortification' in small communities, the process of a small town being converted into a resort destination with numerous vacation properties, increasing absentee business ownership, a highly seasonal economy and escalating real estate prices. Less is known about how the challenges of resortification and industrial tourism interact with the dimensions of community resilience within a gateway community. Community resilience exists as a mechanism for rural and remote communities to identify vulnerabilities, buffer change, develop resources and promote local progress during periods of uncertainty and stress. This paper explores how the snowmobiling restrictions and winter use management of Yellowstone National Park impacted the community resilience of the tourism-dependent gateway community of West Yellowstone. The debate over winter use management and snowmobiling restrictions in Yellowstone National Park drained the community resources of West Yellowstone and negatively impacted the economic viability of local wintertime businesses. Consequently, challenges of resortification intensified and diminished several dimensions of West Yellowstone's community resilience. The mixed methods approach provides insight to how West Yellowstone's social and economic well-being have been affected since the snowmobiling restrictions were implemented and how the tourism landscape of the entire Yellowstone region has changed. The case study of West Yellowstone contributes knowledge of the economics of gateway communities, the implications of federal land management decisions, and the community resilience of tourism-dependent, gateway towns.Item Winter survival and habitat as limiting factors for Arctic grayling at Red Rock Lakes National Wildlife Refuge(Montana State University - Bozeman, College of Letters & Science, 2016) Davis, Michael Nordstrom; Chairperson, Graduate Committee: Thomas E. McMahon; Thomas McMahon was a co-author of the article, 'Factors affecting winter hypoxia in a large boreal lake: evidence for a hypoxia refuge and for reoxygenation prior to spring ice loss' submitted to the journal 'Transactions of the American Fisheries Society' which is contained within this thesis.; Thomas McMahon and Molly Webb were co-authors of the article, 'Winter survival, habitat use and hypoxia tolerance of Arctic grayling in an ice-covered boreal lake prone to winterkill' submitted to the journal 'Transactions of the American Fisheries Society' which is contained within this thesis.Arctic grayling (Thymallus arcticus) are a now rare, glacial relict species occupying only a fraction of their historic range in Montana. The population in Upper Red Rock Lake is the only significant remaining native, adfluvial population and has undergone significant declines in abundance and distribution. Previous studies have documented instances of very low winter DO in the lake and low overwinter survival due to winter hypoxia has been hypothesized as a potential limiting factor for this population. We tested this hypothesis using a combined laboratory and telemetry study to document extent of hypoxia in Upper Red Rock Lake over two winters and assess the physiological tolerance, behavioral response and winter survival rate to hypoxia. In the laboratory study we observed a significant behavioral and physiological response to DO < 4 mg/L and determined 24-hr LD 50 values of 0.75 mg/L for adults and 1.50 - 1.96 for juveniles at temperatures of 1 - 3°C. In the field study we recorded a period of significantly lower lakewide average DO as well as high spatial variability in DO concentration (< 1 - 10 mg/L) during ice cover. However, we found that 69 - 100% of the lake epilimnion had DO > 4 mg/L during the ice cover period of both winters. Results of the telemetry study indicated adult winter survival rate was high (0.97 in 2014, 0.95 in 2015) and that telemetered fish selected deeper, more oxygenated habitat during ice cover. Our study demonstrates that Arctic grayling have a very high tolerance to acute hypoxia exposure and exhibit a physiological and behavioral stress response to DO < 4 mg/L. Although hypoxia was present in Upper Red Rock Lake, ample suitable habitat was available in the epilimnion in both study winters. Despite the potential for a hypoxia threat to develop in more severe winters, we conclude that low winter survival due to winter hypoxia is likely not a limiting factor for this population.Item Winter ecology of moose on the Northern Yellowstone Winter Range(Montana State University - Bozeman, College of Letters & Science, 2003) Tyers, Daniel BruceItem Effect of natural selection on winter survival and associated traits in winter barley composite cross CCXXVI(Montana State University - Bozeman, College of Agriculture, 1988) Hensleigh, Patrick Frank