Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
Browse
7 results
Search Results
Item Out-migration dynamics of juvenile adfluvial bull trout in tributaries to the lower Clark Fork River, Montana(Montana State University - Bozeman, College of Letters & Science, 2021) Lewis, Madeline Collier; Chairperson, Graduate Committee: Christopher S. Guy; Christopher S. Guy, Eric W. Oldenburg and Thomas E. McMahon were co-authors of the article, 'Demographic characteristics and distribution of juvenile adfluvial bull trout at the tributary scale' submitted to the journal 'Transactions of the American Fisheries Society' which is contained within this thesis.; Christopher S. Guy, Eric W. Oldenburg and Thomas E. McMahon were co-authors of the article, 'Seasonal capture efficiencies influences knowledge of underlying out-migration dynamics in bull trout populations with juvenile downstream trap-and-haul programs' submitted to the journal 'North American journal of fisheries management' which is contained within this thesis.; Christopher S. Guy, Eric W. Oldenburg and Thomas E. McMahon were co-authors of the article, 'Individual characteristics and abiotic factors influence outmigration dynamics of juvenile bull trout' submitted to the journal 'Canadian journal of fisheries and aquatic sciences' which is contained within this thesis.In the lower Clark Fork River, Montana, a two-way trap-and-haul program is implemented to conserve the adfluvial life-history strategy in Bull Trout Salvelinus confluentus populations in the presence of hydropower dams. We used the infrastructure in place for the program, including a permanent weir trap and multiple stationary PIT antennas, to evaluate the demographic characteristics and out-migration dynamics of juvenile bull trout, and assess the efficacy of the downstream trapping component of the trap-and-haul program. We PIT-tagged 821 juvenile Bull Trout in Graves Creek, and 144 Bull Trout in East Fork Bull River in the summer of 2019 and summer of 2020. Bull Trout in Graves Creek were primarily age 1 and age 2, with a small number of age-3 Bull Trout present (< 1%). In East Fork Bull River, age-3 Bull Trout represented 14% - 46% of the population, with a small number of age-4 and older Bull Trout present (4% - 6%). From July 2019 through December 2020, 308 tagged Bull Trout outmigrated from Graves Creek, and most out-migrants were age 2 (n = 221). In East Fork Bull River, 18 Bull Trout out-migrated, and most out-migrants were age 3 (n = 13). Capture efficiency of the permanent weir in Graves Creek varied from 83% to 100% in autumn 2019 and 2020 and was substantially lower in the spring (14%). The majority of Bull Trout out-migrated from Graves Creek during autumn 2019, spring 2020, or autumn 2020 trapping seasons (n = 276). In Graves Creek, the largest Bull Trout within the 2018 year-class were five times more likely to out-migrate at age 1 when compared to smaller fish within the cohort. The magnitude of age-1 out-migration was positively related to density. Relative changes in abiotic factors, including discharge, water temperature, and photoperiod, were cues to out-migration, and the direction of change varied by season. Understanding the demographic characteristics and outmigration dynamics of the Bull Trout in Graves Creek and East Fork Bull River enables more informed management of the trap-and-haul program and can be used to inform conservation efforts of other migratory Bull Trout populations.Item Investigating diverse sources of variation in the amount of time Weddell seal (Leptonychotes weddellii) pups spend in the water during the lactation period(Montana State University - Bozeman, College of Letters & Science, 2020) Petch, Shane Morgan; Chairperson, Graduate Committee: Jay J. RotellaThe early-developmental period can have important consequences for offspring success later in life. Phenotypic differences among parents and offspring influence energy availability as well as patterns of allocation and trade-offs during development. Variation in behavioral development prior to weaning may be an important determinant of post-weaning success. Here, we use hierarchical Bayesian models and a long-term database of phenotypic characteristics to investigate sources of variation in total time spent in the water and age at first entry in Weddell seal pups from 11-30 days of age. We found that time in the water was greater for pups with higher birth mass, greater for female than for male pups, lower for pups first entering the water at older ages, had a quadratic relationship with maternal age that peaked at intermediate maternal ages, and was higher for pups born to mothers who skipped reproduction the previous year than those born to mothers that were pre-breeders or reproduced the previous year. Some mothers consistently gave birth to pups that spent more time in the water. Age at first entry was earliest for pups with higher birth mass born to mothers with above average reproductive experience. Maternal identity accounted for slight variation in age at first entry. We document that the first entry can occur as early as 4 days old, but on average occurs at age 14 days. Pups born heavier may have more stored energy to allocate to activity or mitigate costs of submergence. Male pups may spend less time in the water to compensate for higher developmental costs. We found support for proxies of maternal body condition but not maternal behavior in describing time in the water, although maternal reproductive experience was supported in our analysis of age at first entry. Our results indicate that some variation in time spent in the water can be explained by the phenotypic characteristics of mothers and pups, though unaccounted-for sources of variation could be involved. It would be useful if future studies would investigate additional sources of variation and seek to understand how time spent in the water is related to post-weaning outcomes.Item Experimental induction of territorial behavior in the deer mouse, Peromyscus maniclatus(Montana State University - Bozeman, College of Agriculture, 1969) Salonen, James JohnItem Movements and homing of cutthroat trout (Salmo clarki) from open-water areas of Yellowstone Lake(Montana State University - Bozeman, College of Agriculture, 1968) Jahn, Lawrence AllanItem Variation in temporary emigration and survival rates and implications for recruitment for female Weddell seals(Montana State University - Bozeman, College of Letters & Science, 2012) Stauffer, Glenn Elton; Chairperson, Graduate Committee: Jay J. RotellaThe life-history of many colonial-breeding species includes a period of absence from the natal colony followed by a period of attendance as prebreeders prior to first reproduction. During this prebreeder period, survival rates, and the probability of temporary emigration is variable, and patterns of attendance can have implications for future reproduction. We used 26 - 28 years of encounter data of female Weddell seals (Leptonychotes weddellii) in Erebus Bay, Antarctica to estimate variability in survival and temporary emigration rates and to evaluate implications for recruitment rates. Temporary emigration rates were nearly 1 at age 1, decreased until age 8, and increased slightly thereafter. Annual variation in temporary emigration rates was substantial, and rates were positively related to the distance from the fast-ice edge to Erebus Bay and to the population of adult females in the previous year. Recruitment rates varied annually, and were typically, but not always, positively related to the number of years (0, 1, 2+) that a prebreeder had previously attended reproductive colonies in Erebus Bay. Survival rates varied by birth-cohort and were positively related to the extent of current-year winter sea-ice in the Ross Sea. The influence of birth-cohort on survival rates was persistent for several years but did not last indefinitely. Survivorship from birth to age 6 was related to the specific sequence of sea-ice conditions experienced by each cohort, and cohort-specific rates varied from 0.13 (SE = 0.04) to 0.42 (SE = 0.06), and averaged 0.25 (SE = 0.02). Our results suggest that (1) the influences on survival of conditions experienced in early life, along with later influences, act as a filter that determines what proportion of a cohort of female Weddell seals reaches reproductive maturity, and (2) there are benefits and potential costs to prebreeders that are associated with attending reproductive colonies, and the decision to attend or not likely depends on the balance of consequent tradeoffs. Useful avenues for additional research include (1) inter-annual movements within and outside Erebus Bay, especially in relation to previous-year conditions, and (2) implications of prebreeder attendance patterns and age at first reproduction for reproductive success after recruitment.Item Behavioral responses of elk to winter wolf predation risk in the Madison Headwaters area, Yellowstone National Park(Montana State University - Bozeman, College of Letters & Science, 2009) Gower, Claire Natasha; Chairperson, Graduate Committee: Robert A. GarrottOver the past few decades a large body of literature has provided evidence that predators can influence the ways in which prey behave. This in turn may influence prey demography and predator-prey dynamics and therefore predators may influence the structure and function of populations and communities, independent of direct killing. Using data collected from 1991 to 2007, I evaluated the behavior of elk (Cervus elaphus) in the Madison headwaters area of Yellowstone National Park in response to the colonization and establishment of wolves (Canis lupus). Changes in home range size, fidelity, group size, foraging behavior, and large-scale spatial responses were evaluated. After wolf colonization, elk movements were more dynamic as elk moved more over the landscape as they were increasingly encountered, attacked, and displaced by wolves. Home range sizes were larger, with slight decreases in fidelity. These results show that elk made modest adjustments in space use presumably to reduce their vulnerability from predators at a fine-scale within their range. More dramatic larger scale spatial shifts were also documented as radio-collared elk adopted long-distance dispersal and migratory movements away from high-density wolf areas. These apparent predator-avoidance movements were never observed prior to wolf colonization or from areas where the risk of predation was lower. Prior to wolf colonization, the grouping behavior of elk was relatively stable and predictable as elk attempted to conserve energy and decrease starvation risk in the absence of wolves. Following wolf reintroduction group size and group size variation increased. This more dynamic behavior likely reflects a strategy to minimize predation risk and maximize food acquisition. The decision to forage was heavily influenced by local snow, habitat type, and time of day but remained relatively stable with and without the presence of wolves. The lack of any substantial change in the foraging behavior of elk in the presence of wolves illustrates that elk can maintain the same level of foraging time and retain a relatively constant level of nutrition. Together these results suggest that in a harsh winter environment such as the Madison headwaters, elk can adaptively manage their behavior to cope with environmental constraints both in the presence and absence of wolves. Landscape variation such as snow pack severity and habitat types, complexity, and patch size also influences predation risk and may dictate the way in which prey behave.Item Elk (Cervus elaphus) vigilance levels in response to predation risk from wolves (Canis lupus)(Montana State University - Bozeman, College of Letters & Science, 2007) Liley, Stewart Grayson; Chairperson, Graduate Committee: Scott CreelMany studies have shown that levels of antipredator vigilance are sensitive to variation in prey attributes, such as age, sex and group size. It is also well established that vigilance is sensitive to environmental effects, such as the presence of cover. In contrast, little is known about the sensitivity of vigilance to variation in factors associated with the predator itself, such as proximity, the size of the threatening group, and cues about motivation to hunt. Finally, little is known about the relative importance of these three classes of variables (predator, prey, and environment), or about the information content of simple versus complex models of vigilance. We quantified the vigilance levels of elk (Cervus elaphus) preyed upon by wolves (Canis lupus) in Yellowstone National Park, between January and May in 2005 and 2006, and compared a set of 38 regression models for vigilance levels, using Akaike's Information Criterion.