Declining populations of plant and animal species is a major concern threatening global biodiversity. If we want to conserve threatened species, we must understand the requirements of the species. Recent data suggests Golden Eagle populations in the Western United States are declining. Future threats from expanded energy development, habitat loss and climate change are also a concern. Apparent declines and perceived threats have caused management agencies to classify the Golden Eagle as a species of concern requiring the creation of conservation plans. Yet, an effective conservation plan is dependent on information that is currently lacking. To address this lack of available information, I studied a population of breeding Golden Eagles in south-central Montana which has increased in the last 50 years. I was interested in determining which factors were responsible for the increase in the population and changes in measures of breeding performance. I used information from the current phase to identify which environmental factors are important for the eagles now and assessed whether the identified factors were responsible for the documented changes since the 1960s. I found that Golden Eagles in the current phase were selecting areas for nesting territories based on prey habitat and terrain ruggedness. Within their territories, Golden Eagles selected areas conducive to uplift dependent on proximity to prey habitat, on a western aspect and closer to their nest. My results related to measures of breeding performance were unclear. I found prey habitat was likely not limiting the probability of territories being occupied between phases but instead, anthropogenic disturbance was likely limiting the historic population. My results suggest management plans should focus current protection on areas with prey habitat in close proximity to topography eagles can use to exploit uplift. To better understand the current population trends, I suggest expanding monitoring efforts to areas without a large degree of habitat loss in the last 50 years and to unprotected areas. Golden Eagle populations in these locations may be more indicative of the current status of the population range-wide.

The woodland caribou (Rangifer tarandus caribou) population in Newfoundland has been declining since the mid-1990s, and will likely continue to decline into the foreseeable future. This decrease in numbers has been accompanied by a large drop in recruitment. Predation is the primary cause of caribou calf mortality in Newfoundland, and since 2003, >80% of radio-collared calves died within the first 6 months of life. Two Newfoundland herds also have shifted their calving grounds over the past 15 to 20 years. Our objective was to investigate why these shifts have occurred. We analyzed female telemetry locations spanning 29 years, to delineate early-use (1980s and 1990s) and late-use (2003 and 2010) calving grounds, and to compare use and availability within and across these early- and late-use areas. We used a resource selection framework and evaluated shifts with respect to land-use, landcover, and NDVI over time. We found that females were not avoiding human disturbance or responding to climatic changes, but instead were changing selection choices. Models indicated that caribou were selecting for post-burn vegetation and more cover in late-use calving grounds. These results will likely help direct future research and management decisions to boost calving success in Newfoundland.

No description available.

Identification of population structure and connectivity is important for understanding and managing animal populations, in part, because they can influence spread of disease. Respiratory disease is one of the most important factors affecting populations of bighorn sheep and transmission of disease is believed to occur via direct contact. Therefore, risk of disease spread is related to the level of connectivity in bighorn sheep populations. We investigated population subdivision and connectivity of bighorn sheep across central Idaho at behavioral (fine) and genetic (broad) scales. We assessed fine-scale connectivity within a bighorn sheep population using radio telemetry data from 56 individuals from 2007-2013. We defined social groups of bighorn sheep using cluster analysis and estimated connectivity between these groups using a multi-state mark-recapture model. We evaluated the effects of sex, age, and season on the probability that an individual from one social group would transition into the area of another social group. We found that social groups of bighorn sheep along the lower Salmon River were well connected. While males were the primary source of connectivity between social groups, ewes also transitioned into other social groups but to a lesser degree. Rams had a 3 times higher probability of moving during the winter associated with the rut than during the summer. We employed genetic techniques to assess broad-scale connectivity across a metapopulation of bighorn sheep in Idaho using nuclear and mitochondrial DNA from 410 and 206 individuals, respectively. We defined subpopulations of bighorn sheep using a Bayesian clustering program and examined connectivity between these subpopulations using measures of genetic differentiation. We also looked at the contribution of males and females to connectivity. We found evidence for 4 subpopulations of bighorn sheep where 3 of those subpopulations were well connected. We observed some connectivity due to females but population connectivity was largely the result of male movements and dispersal. If contact is sufficient for disease transmission, then males are the most likely vector of disease spread given an outbreak at each scale.

Annual reproductive variation is the central focus of many ecological studies. Variation in reproductive success is an important vital rate to study because it can lead to inferences about population health, extinction risk, human disturbance and habitat quality. The identification of the causes of reproductive variability can help guide conservation and management efforts of a species. In Glacier National Park, Montana I studied causes of annual reproductive variation and behavioral responses to human disturbance in a breeding population of harlequin ducks (Histrionicus histrionicus). Harlequins are rare sea ducks with a Holarctic distribution and winter along rocky coast lines of North America. Females reach reproductive maturity at age 3. At this time they bond with a male that they will breed with for life. Recent band re-sighting has revealed that these ducks can live up to at least 21 years. In spring pairs migrate inland to the females natal montane stream to breed. My study focused on the breeding season from April September on Upper McDonald Creek, Glacier National Park, Montana. My objective was to study 3 potential indirect and direct sources of reproductive variation in Harlequin ducks on this breeding stream; 1) stream flow effects on annual reproductive success, 2) human presence and effects on stream patch occupancy and resource selection, and 3) carry-over effects of physiological measures of body condition, baseline corticosterone levels (primary stress hormone in birds), and integrated measures of corticosterone deposition in feathers. For my first objective I identified 4 different parameters of stream flow that accounted for 32% of the annual variation in reproductive success. I conclude that these parameters will be very sensitive to climate change, making reproduction challenging for harlequins into the future. For my second objective I found greater probability of occupancy of ducks in high human use sites and in stream patches closer to roads. I also found greater occupancy in pool habitat; surprisingly, this pool habitat also had a greater distribution close to road. I conclude from this analysis that there were no strong negative effects of human disturbance on harlequin duck occupy and resource selection, but recommend that harlequin habitat near to human use areas be monitored closely. For my third objective I found that concentrations of corticosterone deposited in feathers grown just prior to reproduction predict reproductive success for that year. I did not find any predictive value of body condition or baseline corticosterone levels. The carry-over effects that I documented in the feathers grown during the prenuptial molt indicate that is an import period that reflects reproductive decision (may be 2 month separation from feather growth to egg lay). These 3 lines of inquiry identified important sources of annual reproductive variation and will help guide management and conservation efforts. I recommend further study to better understand important resources that harlequins select for on the breeding stream and intensive study of harlequin wintering habitat, especially prenuptial molt areas.

The Kittlitzs murrelet (Brachyramphus brevirostris) is a small alcid endemic to Alaska and eastern Russia. Due to its pelagic lifestyle, researchers lack information regarding environmental conditions experienced by Kittlitzs murrelets throughout the year and how these conditions impact their physiology and vital rates. Further, unlike most seabirds, the Kittlitzs murrelet is a dispersed nester; therefore, data are limited for this species even within the breeding season. The goal of this research was to evaluate and improve the monitoring methods for the Kittlitzs murrelet throughout the year. I approached this goal from 2 different perspectives. First, I worked to clarify abundance and trend estimates that have been questioned due to uncertainty in species identification. Second, I used physiological measures to examine the relationships between stress, parental investment, breeding propensity, and environmental conditions experienced by Kittlitzs murrelets throughout the year. To address uncertainties in species identification, I conducted a field experiment to quantify misidentification and non-identification rates of Brachyramphus murrelets during abundance surveys and evaluate the impacts of covariates on each. I found that misidentification of species was rare and did not bias abundance estimates. Additionally, non-identification was common beyond observation distances of 140 m, though this depended on observer experience, murrelet behavior, and sea conditions. To understand the environmental conditions experienced by Kittlitzs murrelets throughout the year, I measured corticosterone (avian stress hormone) and prolactin (parental expression hormone) and evaluated their relationships with breeding propensity and ocean productivity metrics. Higher levels of stress during the pre-and post-breeding seasons reflected lower rates of breeding propensity in the following season. Additionally, higher stress was associated with lower sea surface temperatures during the pre-breeding season, and earlier capture dates, longer time-spans between capture and processing, and lower body mass during the late-breeding season. Prolactin positively reflected CORT during the early breeding season and sex during the late breeding season. These results emphasize the need for continued research to understand the mechanisms linking the stress physiology, foraging ecology, and breeding ecology of the Kittlitzs murrelet and other species that depend on similar resources.

Headwater streams in forested landscapes are generally lacking in primary productivity and rely on allochthonous inputs to fuel secondary production. This close association with the forested landscape makes these streams sensitive to terrestrial disturbances. In the Greater Yellowstone Ecosystem (GYE) a climate change induced mountain pine beetle (Dendroctonus ponderosae, MPB) outbreak has been decimating whitebark pine (Picea albicaulis, WbP) forests over an extremely short time period. Among the possible implications of widespread WbP die-off, I predicted an increase in litter inputs to headwater streams and an increase in the quality (nitrogen content) of these litter inputs both of which would alter rates of organic matter processing and invertebrate communities in headwater streams. To test these predictions I quantified the mode of transport and rate of litter inputs to headwater streams in the GYE within ten streams distributed between two basins of differing levels WbP mortality and surveyed benthic invertebrate populations within those streams to determine whether MPB-mediated WbP mortality had an effect on detritivore communities. In addition, I carried out an experiment to compare differences in decomposition between needles from healthy WbP and those killed by MPB in a single stream within the high-mortality basin. Inputs of WbP needles were higher to streams in the basin with greater WbP mortality and these inputs were primarily entering streams via vertical transport. However, despite the increased quantity of inputs into these streams I found that invertebrate densities declined as WbP mortality increased. Furthermore, I discovered that naturally senescent needles from healthy trees decomposed faster than needles from MPB-killed trees despite higher nutrient levels in the MPB-altered needles. Although MPB attack does result in WbP litter with higher C:N than that which is associated with healthy trees, these needles may also contain elevated levels of defense compounds with insecticidal and anti-fungal properties. Further research is needed to determine whether possible MPB-induced increases in monoterpene concentrations affect needle decomposition. However, my results indicate that MPB infestations slow rates of nutrient processing in headwater streams despite an increase in litter quantity and quality.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 214-224). Also available via the Internet.

Thesis (Ph. D.)--University of Michigan, 1952. / Includes bibliographical references (leaves 330-335).

Thesis (M.S.)--University of Wisconsin--Madison, 1943. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.