Scholarship & Research
Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/1
Browse
7 results
Search Results
Item Distribution, phenology, growth, and overwinter mortality of age-0 smallmouth bass in the Yellowstone River, with implications for upstream range expansion(Montana State University - Bozeman, College of Letters & Science, 2020) Voss, Nicholas Sheridan; Chairperson, Graduate Committee: Alexander V. Zale; Robert Al-Chokhachy, Adam J. Sepulveda, Christine E. Verhille, Michael P. Ruggles and Alexander V. Zale were co-authors of the article, 'Distribution, phenology, growth, and overwinter mortality of age-0 smallmouth bass in the Yellowstone River, with implications for upstream range expansion' submitted to the journal 'Transactions of the American Fisheries Society' which is contained within this thesis.Non-native fish introductions are a leading threat to freshwater biodiversity, and accurate assessments of future impact are often hindered by the challenge of anticipating future range expansion. Successful introductions of non-native Smallmouth Bass Micropterus dolomieu have occurred globally and often exhibit secondary spread to upstream habitat. This has occurred in the Yellowstone River, Montana (USA). Observations of adults in socio-economically valuable trout habitat have highlighted a need to better understand the controls on the upstream distribution of Smallmouth Bass in this system, particularly the influence of cold upstream climates on first-year growth and size-selective overwinter mortality (a potential life history bottleneck at northern latitudes). We documented the phenology, growth, and survival of age-0 Smallmouth Bass in relation to water temperature between the uppermost distribution of adults, and downstream regions where they are abundant. Successful reproduction (i.e., age-0 presence) was rare or absent throughout the uppermost 150 km of the upstream distribution of adults, suggesting that something currently prevents or discourages successful reproduction farther upstream. Surprisingly, the mean late-autumn body size of age-0 Smallmouth Bass did not differ significantly among the uppermost 200 km of their distribution, despite upstream declines in ambient water temperature. Although water temperature was a key attribute affecting age-0 growth, upstream shifts towards earlier hatching mediated the expected negative effect of colder upstream climates. Furthermore, surveys of overwinter survivors and simulations of age-0 starvation mortality indicated that age-0 individuals at the upstream extent of their distribution successfully recruited to the age-1 year-class in four consecutive years. Taken together, our results suggest that Smallmouth Bass have not yet reached the thermal limit of their upstream distribution, and that first-year growth, survival, and consequent spread by this non-native predator are probably driven by the complex interactions of spawn timing and ambient thermal and hydrologic regimes in the Yellowstone River.Item Description of the reproductive structure, size, growth, and condition of hatchery-origin white sturgeon in the lower Columbia River, British Columbia, Canada(Montana State University - Bozeman, College of Letters & Science, 2020) Maskill, Paige Anne Camas; Chairperson, Graduate Committee: Christopher S. Guy; James A. Crossman, Christopher S. Guy and Molly A. H. Webb were co-authors of the article, 'Describing the reproductive structure of the hatchery-origin population of white sturgeon in the lower Columbia River, British Columbia, Canada' which is contained within this thesis.Conservation aquaculture has been successful in preventing extirpation of endangered white sturgeon Acipenser transmontanus in the lower Columbia River (LCR), Canada. The goals of this project were to 1) determine if the hatchery-origin (HO) population has reached puberty as many fish are of an age and body size to begin contributing to spawning and 2) assess the size, absolute growth rate (AGR), and relative condition factor (Kn) of the population. The reproductive structure (sex and stage of maturity) of the HO population was assessed using multiple tools (gonadal biopsy analyzed histologically, ultrasound, endoscopy, and plasma sex steroids). The accuracy of each tool was determined by comparing the assigned sex to the true sex determined by histological analysis of a gonadal biopsy. A subobjective was to determine whether gonadal development was homogenous (assessed in fish captured in LCR and Lake Roosevelt, WA, USA). All fish assessed were pre-meiotic males (n=158) or pre-vitellogenic females (n=174) and had yet to reach puberty. Endoscopy and gonadal biopsy analyzed histologically were the most accurate tools with accuracies > 97%. Gonadal development was homogenous in females but 38% of the males exhibited non-homogenous testicular development, with a few precocious cysts that contained germ cells in an advanced stage of development compared to the predominant phase seen throughout the biopsy. The size, AGR, and Kn were compared among sex, age, and river zone. While the mean Kn indicated that the HO white sturgeon were in average condition relative to all HO fish within the LCR, they were lower in condition compared to the full transboundary population (Canada and USA). This reflects a difference in the environmental or physiological conditions of the fish in the LCR and those captured throughout the transboundary reach. Results of this work will be important to determine the reproductive dynamics of the hatchery-origin population over time (e.g., age and size at puberty, sex ratio), and specifically when these fish will begin spawning in the wild. Additionally, this information will help to develop other standardized monitoring programs which can track the reproductive structure of a population over time using tools with known accuracy rates.Item Influence of thermal regime on the life histories and production of Rocky Mountain aquatic insects(Montana State University - Bozeman, College of Letters & Science, 2019) McCarty, Jennifer Denise; Chairperson, Graduate Committee: Wyatt F. CrossLife history traits of aquatic insect taxa such as metabolism, terminal body size, and fecundity vary along natural thermal gradients. Body size, in particular, is expected to respond to temperature and may have important consequences for fecundity and the production of insects. The Thermal Equilibrium Hypothesis (TEH) predicts that aquatic insect taxa are most abundant at an intermediate 'optimal' temperature where life history traits such as terminal body size and reproductive potential are maximized, i.e., the thermal 'optimum'. A competing hypothesis, the Temperature Size Rule (TSR), predicts that individuals developing at the coldest temperatures in their range will grow more slowly, but attain the largest body sizes and therefore exhibit greater fecundity than individuals growing at warmer temperatures. Implicit in both of these theories is that population-level production, a measure of population 'success', will be greatest where terminal body size and fecundity are maximized. Few studies have investigated the TEH in the field, and none have measured the relationship between production and other life history traits in the context of these theories. Our study focused on three common Rocky Mountain aquatic insect taxa: Drunella doddsii, Hydropsyche cockerelli, and Ephemeralla infrequens. We quantified the influence of thermal regime on growth rates, terminal body size, reproductive potential, and population-level biomass and production, all of which potentially limit the longitudinal distribution and success of these taxa. We found that growth varied strongly with season and site, leading to significant variation in the timing of growth and terminal body size. Reproductive potential was negatively associated with mean annual temperature as predicted by the TSR. Unexpectedly, reproductive potential was not always correlated with terminal body size. Population density, biomass, and secondary production were generally positively correlated with terminal body size for D. doddsii and H. cockerelli, as expected from both predictive models. In contrast, these relationships were not as consistent for E. infrequens. Our findings provide new insight as to how thermal variation influences the ecology of aquatic insects in the context of the TEH and TSR. Our results should be valuable for predicting population and community responses to ongoing changes in climate.Item Exploring the role of water in tree growth and what trees can tell us about the hydroclimate of the past(Montana State University - Bozeman, College of Letters & Science, 2018) Martin, Justin T.; Chairperson, Graduate Committee: David Roberts; Jia Hu (co-chair); Nathaniel Looker, Zachary Hoylman, Kelsey Jencso and Jia Hu were co-authors of the article, 'Hydrometeorology organizes intra-annual patterns of tree growth across time, space, and species in a montane watershed' in the journal 'New phytologist' which is contained within this thesis.; Nathaniel Looker, Zachary Hoylman, Kelsey Jencso and Jia Hu were co-authors of the article, 'Differences in the use of winter precipitation by conifers along an elevation gradient in the northern Rockies' submitted to the journal 'Global change biology' which is contained within this thesis.; Gregory Pederson, Connie Woodhouse, Edward Cook, Gregory McCabe and Kevin Anchukaitis were co-authors of the article, 'Unprecedented drought intensity tracks recent warming in the headwaters of the United States' largest river basin' submitted to the journal 'Nature climate change' which is contained within this thesis.Here, we revisit the role of water potential in tree growth control using a field-based approach to exploring the role of soil moisture supply and atmospheric moisture demand on tree water potential and subsequently, growth. We explore how limitation in tree radial growth can be well predicted by local hydrometeorlogical conditions and associated tree water potentials, and observe that such limitation occurs under conditions that are considerably more mesic than those associated with the onset of photosynthetic limitation resulting from stomatal regulation (Martin et al., 2017). While direct observation of tree xylem growth and growth limitation remains a very challenging problem, our findings provide strong evidence for the role of Psi x in the regulation of tree radial growth in dry environments...Because one of the most prominent features of observed climate change in the American West has been an advancement in the timing of spring conditions (Cayan et al., 2001; Stewart et al., 2005), developing a better understanding of how the timing of moisture delivery and tree growth relate is an important research goal. Using a field-based study carried out over three years in western Montana, we quantified the timing and magnitude of moisture delivery to a forest ecosystem, and coupled this to isotope-based observations of where in the soil profile trees sourced water from as well as the seasonal evolution of radial growth. This allowed us to estimate the importance of winter precipitation relative to summer rains for growth in trees over the growing season. This work establishes a baseline understanding of how temporal dynamics of moisture delivery to forests and tree growth relate in time and can help guide our understanding of how ongoing changes to climate conditions may affect tree growth in the future...In order to better understand the hydroclimatic dynamics of the Missouri river, we developed a network of tree ring based reconstructions of streamflow spanning 1200 years for every major tributary across the mountain headwaters of the Missouri river. We examined the history of basin-wide drought events evident in the tree ring record in the context of reconstructed temperature and explored how the relationship between temperature and streamflow has changed over time. As a result, it is evident that rising temperatures create new challenges for water managers and users in the Upper Missouri River Basin that are likely to increase as temperatures warm in the future.Item Growth rates and movements within a population of Rana pretiosa pretiosa Baird and Girard in South Central Montana(Montana State University - Bozeman, College of Agriculture, 1974) Hollenbeck, Robert RudolphItem Identification of life history variation in salmonids using otolith microchemistry and scale patterns : Implictions for illegal introductions and for whirling disease in Missouri River Rainbow trout(Montana State University - Bozeman, College of Letters & Science, 2004) Munro, Andrew Roy; Chairperson, Graduate Committee: Thomas E. McMahon; Alexander V. Zale (co-chair)Proper conservation and management of wild salmonid populations requires correct identification of the array of life histories present and their contribution to adult recruitment. I used otolith microchemistry to identify natal origin and scale patterns to determine outmigration age in Missouri River rainbow trout where whirling disease could potentially cause a population collapse. First, I reviewed the otolith microchemistry literature and concluded that there have been a limited number of freshwater studies, and there has been limited rigorous testing of the many instruments used. Second, I tested the efficacy of time-of-flight secondary ion mass spectrometry (ToF-SIMS) and found that Sr:Ca could be precisely measured in an otolith 'standard', there is a strong relation between qualitative ToF-SIMS results and concentrations measured with an electron microprobe, and the ambient water strongly influences otolith composition. Third, I analyzed the chemical composition of lake trout otoliths to identify the likely source of illegally transplanted lake trout in Yellowstone Lake. Changes in otolith microchemistry of suspected transplants accurately (>90%) determined the likely source of the introduction, and transect analyses indicated that lake trout have possibly been in Yellowstone Lake since as early as the mid-1980s. Finally, I used otolith microchemistry to identify natal origin and scale patterns to identify outmigration age in Missouri River rainbow trout. Otolith microchemistry was not an effective technique for this particular system because of similarities between the two major rainbow trout producing tributaries. However, I demonstrated a technique that uses the relation between otolith and water Sr:Ca to estimate sample sizes required to detect differences between streams. This can be used in future studies as a preliminary test to determine if otolith microchemistry is feasible. Scale patterns revealed that the yearling outmigration life history contributed most (88%) to adult recruitment in the mainstem fishery and the proportion of young-of-the-year to yearling outmigrants did not change post-whirling disease. Rainbow trout in the Missouri River have two obstacles to overcome: 1) severe whirling disease infection if the natal stream has Myxobolus cerebralis; and 2) low probability of surival if they manage to avoid severe infection but leave the stream too early.Item Mass dynamics of Weddell Seals in Erebus Bay, Antarctica(Montana State University - Bozeman, College of Letters & Science, 2008) Proffitt, Kelly Michelle; Chairperson, Graduate Committee: Robert A. Garrott; Jay J. Rotella (co-chair)An individual's body mass is an important life history trait that may vary with environmental conditions and be related to reproductive performance. In this dissertation, we used a 35-year dataset to investigate variations in body mass of Weddell seals (Leptonychotes weddellii) in Erebus Bay, Antarctica with goals of linking environmental conditions, body mass, and reproductive performance. We predicted that variations in environmental conditions and maternal traits would correlate with variations in maternal body mass at parturition, and that variations in maternal body mass may be linked with offspring's body mass and survival probability. We found maternal body mass at parturition showed substantial age- and environmental-related variations. Maternal body mass increased with age through the young and middle ages, and evidence of senescent declines in body mass was found amongst the oldest ages. Additionally, body mass at parturition was strongly influenced by environmental variations during the pregnancy period, specifically body mass was negatively correlated with sea-ice extent and positively correlated with the Southern Oscillation. Annually, pup weaning mass was highly variable. Pup weaning mass was negatively correlated with summer sea-ice extent and positively correlated with summer Southern Oscillation, and these two variables explained 86% of the annual variation in the population average weaning mass. Weaning mass was positively correlated with juvenile survival probability, particularly for males, and we estimated the odds of a male surviving from weaning to age 3 increased 7.3% for every 10 additional kilograms of body mass accrued by weaning. Together, these results suggest large-scale atmospheric-oceanographic variations may affect Weddell seal maternal foraging success and ultimately reproductive performance. Finally, we investigated statistical methodologies accounting for measurement error in photogrammetrically estimated body mass with goals of developing techniques to employ estimated body mass as a covariate in simple linear regression models. We demonstrated that error associated with estimating body mass induces bias in regression statistics and decreases model explanatory power and we described simple statistical techniques accounting for measurement error in covariates. These statistical developments may allow future studies to employ photogrammetric mass estimation techniques and utilize estimated body mass as a covariate in ecological modeling exercises.