Theses and Dissertations at Montana State University (MSU)
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Item Mortality dynamics and life tables of Megachile rotundata(Montana State University - Bozeman, College of Agriculture, 2019) Donahoo, Claire Katherine; Chairperson, Graduate Committee: Robert K. D. Peterson.; Kevin M. O'Neill, Casey M. Delphia and Robert K. D. Peterson were co-authors of the article, 'Mortality dynamics and life tables of the alfalfa leafcutting bee, Megachile rotundata (Hymenoptera: Megachilidae)' which is contained within this thesis.The alfalfa leafcutting bee, Megachile rotundata (F.), contributes to the pollination of more than two-thirds of alfalfa seed production in North America. However, population losses of more than 50% are common in the U.S., requiring many alfalfa seed producers to import costly bees from Canada. Understanding the mortality dynamics of M. rotundata and being able to estimate these impacts on their populations are critical for identifying ways to conserve and increase their populations. Therefore, this study had three objectives: 1) identify mortality classes for M. rotundata in brood cells; 2) experimentally manipulate parasitism and temperature to determine their impact on total mortality; and 3) estimate mortality risks using the multiple-decrement life table (M-DEC). Research was conducted over two years on a 38.5 ha alfalfa field in Toston, MT. Nest shelters were manipulated for a main temperature treatment (low vs. high) and a sub-treatment for parasitism (backing-present vs. backing-absent). Females constructed and provisioned nests during the summer and offspring mortality was assessed during the summer and the following fall. Mortality classes were then analyzed using the M-DEC model. We found no temperature-treatment effect, so our main treatment was not used in the analyses. However, for every 1 °C increase in nest-tunnel temperature, there was a 7% increase in total mortality. Nest boxes without felt backing (backing-absent) had a 43% increase in mortality over both years compared to those with felt (backing-present). Average temperature decreased by 4.4 °C from 2017 to 2018, while average relative humidity increased by 12.1%. Total mortality was approximately 15% for both years, but the proportion of each mortality class differed substantially, with death by parasitoids greatest in 2017 and death by pollen ball greatest in 2018. Mortality from each class was highly irreplaceable in that it is unlikely to be replaced by another class, and death by predation was the only cause with similar mortality between the two years. The ability to identify and quantify mortality classes and their respective irreplaceable mortality, especially for parasitoids, pollen ball, and predators, will help producers maintain and increase bee populations.Item Risk of morbidity and mortality to native trout on the Fort Hall Indian Reservation, Idaho, due to increased stream temperatures(Montana State University - Bozeman, College of Agriculture, 2014) LodgePole, Ronald Zachariah; Co-chairs, Graduate Committee: Robert K. D. Peterson and Cliff MontagneClimate change is now happening faster than ever. The Fort Hall Indian Reservation (FHIR), is located in Bingham, Power, Bannock, and Caribou Counties, Idaho. To estimate the quantitative risk of morbidity and mortality posed to Yellowstone Cutthroat Trout Oncorhynchus clarki bouvieri on the FHIR, stream temperatures, or at the very least, a robust estimate of stream temperatures, was needed. The first objective was to examine what stream temperature data were available. The second objective was to obtain elevation values for stream temperature monitoring sites within the FHIR. This helped in the third objective, which was to develop a regression model to predict stream temperatures. The fourth objective was to document thermal preferences of YCT. Cross-referencing thermal thresholds of YCT and stream temperatures allowed for the fifth and sixth objective, which was to create a deterministic and probabilistic risk assessment. The seventh objective was to map out the risk assessment and graphically display risk associated with each major stream reach within the FHIR. The results of this study indicate that a substantial amount of suitable YCT habitat within the FHIR will likely be lost due to increased stream temperatures, a direct result of global climate change. At this local scale the bulk of the habitat loss can be expected in the lower elevation areas of the FHIR. Mid to high elevation areas will also be negatively affected but not as much as the lower elevation areas. This effort led to the understanding that stream temperatures for the current time frame have been increasing as a result of climate change. With the projected increases in future July stream temperatures the optimal habitat for YCT will be significantly diminished as well. Therefore, this study may serve as a call to action to all interested parties within the FHIR, State of Idaho, and the Greater Yellowstone Ecosystem. With the gleaned information and understanding of how stream temperatures will put YCT at higher risk of temperature related morbidity and mortality, it is up to the risk managers of the greater FHIR and the FHIR to take whatever action they deem necessary in their unique environmental management responsibilities.Item Factors affecting bear and ungulate mortalities along the Canadian Pacific Railroad through Banff and Yoho national parks(Montana State University - Bozeman, College of Agriculture, 2011) Dorsey, Benjamin Paul; Chairperson, Graduate Committee: Lisa J. Rew.Railroads, roads and associated traffic have been shown to adversely affect ecosystems by killing wildlife and altering the landscape. Relatively little research has been conducted along railroads. Given the probable growth of railroads, it is imperative that we understand the impacts railroads exhibit on wildlife. In this thesis, I reviewed the documented impacts of railroads on wildlife then conducted analyses on data collected along the Canadian Pacific Railroad (CPR) through Banff and Yoho National Parks (~134 km). In the study area, over 1000 train strikes with 26 mammal species have been recorded between 1990 and 2010, which included 579 elk (Cervus elaphus), 185 deer (Odocoileus spp.) and 79 bears (Ursus spp.). The goal of this research was to provide an initial assessment of the factors affecting strikes with ungulates and bears along the CPR. To accomplish these goals, I studied four general factors that have been hypothesized to affect the rate and spatial distribution of strikes. These are: wildlife abundance, anthropogenic foods, and railroad design. I compared strike rates along three mile long rail segments to train spilled grain, train and railroad design variables. I developed an estimate of risk using line transect data so that I could determine if there was evidence for nonconstant strike risk. Statistical models were used to identify which factors best explained strike rates. I detected correlations between the density of train-spilled grain and bear foraging rates but not with bear strikes. I identified locations where corrective measures or mitigation solutions may be needed and identified railroad designs and landscape variables associated with those locations. Hotspots were identified for elk and deer but not bears. Relative abundance was generally correlated with strike rates. High risk locations, where more strikes occurred than were expected, were identified. Train speed limit and right-of-way width was positively associated with strikes for elk and/or deer. For bears, the number of structures (e.g. highway overpasses) and bridges were positively associated with strikes. These results were used to suggest management recommendations including train speed reductions, habitat modifications and railroad design alterations to reduce the risk of strikes.