Browsing by Author "Ruckstuhl, Kathreen E."
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Item Open Access Ecological and behavioural factors affecting philopatry and life history patterns of yellow-bellied marmots (Marmota flaviventris) in the southern Alberta prairie region(2021-01-11) Holland, Berna-Dean; Ruckstuhl, Kathreen E.; Neuhaus, Peter; Ruckstuhl, Kathreen E.; Neuhaus, Peter; Barclay, Robert M. R.; Reid, Mary L.; Sicotte, PascalThe personality of an individual greatly influences its fitness. Yet, most conclusions about fitness, are often drawn from a population level perspective. In this thesis, I underline the importance of studying personality in behavioural ecology, and conservation. This thesis is the product of three years of research into personality, philopatry, and the life-history of yellow-bellied marmots (Marmota flaviventris), occurring in the extreme southern region of Alberta. My research methodology involved a hybrid approach, incorporating both my Métis-Indigenous way of exploring, and experiments drawn from standardized methodologies of western science. This thesis represents the first detailed study of yellow-bellied marmots living within the prairie ecozone of southern Alberta Canada; one of the most northern ranges of this species. In Chapter 1, I present my observational findings of ecology and general life history patterns of this species as it occurs in this region. In chapter 2, I present my investigation into whether personality and sex of individual yellow-bellied marmots living in this region, play a significant role in philopatry; the tendency of individual offspring to remain within their natal home. The experiments revealed consistent response of individual marmots across a variety of situations representing an anti-predator context. However, the only factor found to have an effect on philopatry, was the sex of individuals. I end with a summary of my results and recommendations for future research.Item Open Access Ecological genomics and conservation of caribou in Western North America(2020-09-09) Cavedon, Maria; Musiani, Marco; VonHoldt, Bridgett M.; Mariani, Stefano; Hebblewhite, Mark; Darimont, Chris T.; Ruckstuhl, Kathreen E.Selection can favor different phenotypes along environmental clines. Clines are also compatible with balancing forces, which maintain phenotypic polymorphisms within populations -for example, migratory or sedentary behaviour in caribou. The use of genomics is fundamental to evaluate such evolutionary processes and, in conjunction with ecological information, has also been advocated for to inform conservation planning for endangered caribou. I examined Single Nucleotide Polymorphisms (SNPs) across caribou populations from western North America. I detected population structure and genes under selection within each caribou group. I also analysed seasonal movements and habitat selection using GPS telemetry, and morphological information gathered at capture. Some of the genes under selection in my study were linked to morphological characteristics, migratory behavior, habitat selection and climatic and environmental factors. These findings suggest that exclusive mutations, resulting in different phenotypes, are maintained within caribou groups. Moreover, I detected a signal of balancing selection, a genetic force that maintains genetic polymorphisms within populations. I suggest that this force has a fundamental role in maintaining multiple haplotypes and phenotypes within caribou populations, also including partial migration. In this thesis, I identified genes under selection and patterns of population structure that should be considered in conservation planning and management of caribou populations. Habitats and climate are dramatically changing worldwide, and the genetic aspects of selectivity, that I described, could indicate that caribou may be challenged in their ability to adapt to certain changes. For example, my results indicate a specialization of caribou for cold climates and seasonal foraging in pristine environments, with genes linked to these specializations. In addition, as part of conservation planning, caribou breeding programs have been proposed. A fundamental aspect of these programs is deciding the best source animals, from wild populations, to be used to found captive populations. My population structure results could help inform these programs, as I “practically” suggested for the Southern Canadian Rockies region. Overall, I used an integrative and innovative approach to investigate the link between movement ecology, morphology, genomics, with applications to caribou conservation and conservation of other species, in which genetic traits may also influence behaviour, and limit resilience to changing habitats and climates.Item Open Access The ecology, and life history evolution of the parasitic nematode Marshallagia marshalli, and its adaptability to extreme conditions(2019-07-25) Aleuy Young, Oscar; Ruckstuhl, Kathreen E.; Kutz, Susan; Lafferty, Kevin D.; Cartar, Ralph V.Marshallagia marshalli is a very common, but relatively poorly studied, abomasal nematode infecting a variety of wild ungulates in North America. Despite its economic, social and ecological importance little is known about its impact, life history traits and adaptations to cope with environmental extremes. This parasite has a direct life cycle and the development and survival of its free-living stages are directly influenced by climatic factors, thus are likely to be affected by climate change. The overall aim of my thesis was twofold; i) to understand the development, ecology and impact of M. marshalli, and ii) to use M. marshalli as a model species to study the importance of phenotypic plasticity and local thermal adaptation in the interaction of helminths with climate change. I achieved this using a combination of approaches, including the collection of field data, laboratory experiments, and modelling approaches. Marshallagia marshalli was negatively associated with a variety of fitness indicators of Dall’s sheep, including pregnancy rate and body condition. This negative effect also extended to fetal development and sex allocation through a combination of direct and indirect effects on the fetus and the mother. Hatching of M. marshalli occurred primarily as first-stage larvae (L1) in an advanced stage of development. Less frequently, M. marshalli also hatched as third stage larvae (L3) directly from the egg, with this phenomenon being significantly more common at higher temperatures. Free-living larvae of M. marshalli did not feed nor grow as they matured to infective L3. Eggs and unhatched L1 were significantly more tolerant to freezing compared to free-living L1, suggesting that remaining in the egg as L1, and even to the L3 stage, is an adaptation to cope with the extreme environmental conditions that Marshallagia faces across its extensive latitudinal distribution in North America. Finally, temperature dependent development and mortality rates of free-living stages differed among M. marshalli populations, supporting the hypothesis of local thermal adaptation among populations of this species. When these differences were modelled using classic disease modelling approaches complemented with the Metabolic Theory of Ecology I demonstrated that similar temperature variations have differential impacts on the fitness of M. marshalli from different locations. My research has highlighted the impact of M. marshalli on host fitness at different life stages of the host and demonstrated how subtle differences in the life history traits and thermal tolerances of nematodes can have implications for their persistence in extreme environments and in their response to climate change.Item Open Access The effect of male age on patterns of sexual segregation in Siberian ibex(2018-08-30) Wang, Muyang; Alves, Joana; Alves da Silva, António; Yang, Weikang; Ruckstuhl, Kathreen E.Sexual segregation is very common in sexually size dimorphic ungulates and may be the result of different habitat preferences and/or differential social behaviours of males and females. Various hypotheses have been put forward to explain this phenomenon. In the present research, we examined sexual segregation in a quite poorly-understood species, the Siberian ibex. The species presents a marked sexual size dimorphism, with adult males weighing double as much as females. We use the Sexual Segregation and Aggregation Statistics (SSAS) to analyze the sex-age patterns of sexual segregation in this species, to understand the relevance of social factors. Our results show that adult Siberian ibex males were socially segregated from females all year-round, except during the rutting season. Furthermore, the degree of segregation between females and males was influenced by the age of males. Moreover, the patterns of social segregation within males also increased with male age, reaching maximum values for males of 9-years-old and older, which means male age plays an important role in the sexual segregation of this species. This study clearly shows that social factors play a key role in the sexual segregation of Siberian ibex.Item Open Access Health Surveillance of Thinhorn Sheep (Ovis dalli) Herds in British Columbia and Alaska(2019-09-18) Thacker, Caerleon; Whiteside, Douglas P.; Ruckstuhl, Kathreen E.; Schwantje, Helen M.; Lohuis, Thomas D.; Manlove, Kezia R.The health of wildlife populations influences their sustainability in the face of ecological challenges. There is a paucity of information about the health status of free ranging thinhorn sheep populations (Ovis dalli), despite their economic, ecological, and cultural significance. Identification of health concerns in related species, bighorn sheep (Ovis canadensis), as well as concern from local communities, First Nations, hunters, and conservationists that thinhorn subpopulations may be declining in some areas, prompted the call for comprehensive thinhorn sheep herd health assessments. We used a standardized approach based on similar work on bighorn herd health and conducted herd health assessments of thinhorn sheep in five study herds across their range that included both subspecies, Dall’s sheep (O. dalli dalli) and Stone’s sheep (O. dalli stonei). We used a broad definition of health and surveyed exposure to multiple pathogens common to domestic small ruminants and other wildlife species, and evaluated other comprehensive health measures including nutritional status, parasite burden, contaminant exposure, stress, pregnancy, and indices of body condition. From 2017 to 2020 we collected tissue and blood samples from 46 Stone’s sheep ewes and immature rams live-captured in the Skeena and Peace regions of British Columbia (BC), and 67 Dall’s sheep in the Talkeetna and Chugach mountains of Alaska (AK). We also analyzed samples from 63 hunter-harvested Stone’s sheep rams from the Skeena region of BC from 2016 to 2019. We found evidence of Mycoplasma ovipneumoniae exposure in Dall’s sheep in Alaska and inconclusive results in Stone’s sheep in BC. There was minimal evidence of exposure to other bacterial and viral respiratory pathogens in all subspecies and herds. A high seroprevalence to ovine herpesvirus (P = 89.5%) was detected in all Stone’s sheep. Parasite burdens were similar to previously reported results, including winter tick (Dermacentor albipictus) infestations of Stone’s sheep sampled at low elevation along the Peace Arm of Williston reservoir. A high seroprevalence to Toxoplasma gondii was detected in sheep in Alaska (P = 100% in 2019, and 73.9% in 2020). Fecal glucocorticoid metabolite concentrations determined from hunter-harvested and live-captured sheep increased annually. Serum and tissue copper levels in some herds were in the range considered deficient for domestic sheep. Other trace minerals, including zinc and selenium, were deficient only in some study areas. Body condition of hunter-harvested rams decreased annually from 2016 to 2018. Our findings confirm that thinhorn sheep, in general, are relatively naïve, and in some populations, very naïve, to diseases carried by domestic ruminants and other wildlife species. This information provides a baseline for thinhorn sheep herd health monitoring. If continued, it will allow for early detection of disease introductions and other population-limiting health factors. The results inform conservation and One Health decision-making and can be incorporated into science-based management of thinhorn sheep in BC and Alaska.Item Open Access Molecular Investigation of Wildlife Herpesvirus and Parapoxvirus: Benefits and Limitations of Genetic Characterization of dsDNA Viruses from Tissues(2019-12-18) Dalton, Chimoné Stefni; van der Meer, Frank; Abdul-Careem, Mohamed Faizal; Kutz, Susan J.; Ruckstuhl, Kathreen E.Wildlife populations can be reservoirs or victims of pathogens shared with humans and/or domestic animals. Most diseases at the wildlife-livestock interface are caused by viruses. Herpesviridae and Parapoxviridae are families of important double-stranded DNA (dsDNA) viruses that have been implicated in diseases of wildlife, domestic animals, and humans resulting from spill-over or zoonotic transmission, yet still little is known about viruses circulating in wildlife. Wildlife health surveillance is a primary tool for the management of zoonotic diseases, the control of diseases of domestic animals, and the preservation of wildlife populations. Studies herein conduct molecular surveillance of herpesviruses (HV) and orf virus (a parapoxvirus) through diagnostic polymerase-chain reactions (PCR), sequencing, and phylogenetic analysis using tissues of various wildlife animal species in Canada. The viral DNA polymerase (DPOL) gene is an effective target for the detection and characterization of HV present in infected animals. Previously uncharacterized HV were characterized in marten across Canada, and Reindeer gamma-HV 1 was characterized in caribou from different herds. Phylogenetic analysis suggests HV have coevolved with their wildlife host at a species level. Detection of orf virus was most successful when targeting the viral immunodominant envelope protein gene: B2L. Orf virus was detected in muskoxen on Victoria Island in areas managed by the Northwest Territories (NT) and Nunavut (NU), and on the adjacent mainland of NU, Canada. Orf virus was present in males and females, from calf to adulthood, indicating this virus represents a disease threat for muskoxen. Next-generation sequencing was performed directly on the DNA extracted from tissues of four clinically infected, geographically distant muskoxen in our study area. Phylogenetic analysis revealed Muskox orf virus (MxOV), to be unique from known orf viruses. This thesis documents the diversity of HV circulating in wildlife, increases our awareness of limitations when using tissues for molecular surveillance, increases our understanding of orf virus infection in muskoxen, and highlight areas of much-needed research. Methodologies herein can be adapted for the surveillance of other dsDNA viruses, while the data directly contribute to the database of HV and orf virus sequences in Canadian wildlife that provide context for new or emerging pathogens.Item Open Access Mother's occupation and sex ratio at birth(BioMed Central, 2010-05-23) Ruckstuhl, Kathreen E.; Colijn, Grant P.; Amiot, Volodymyr; Vinish, ErinItem Open Access Parasite Removal Improves Reproductive Success of Female North American Red Squirrels (Tamiasciurus hudsonicus)(PLoS, 2013-02-08) Patterson, Jesse E. H.; Neuhaus, Peter; Kutz. Susan J.; Ruckstuhl, Kathreen E.Item Open Access Patterns of helminth and protozoan parasite infections in bighorn sheep, Ovis canadensis: sex, season and activity(2020-01-07) Rijal, Samridhi; Ruckstuhl, Kathreen E.; Reid, Mary L.; Kutz, Susan J.Males and females in sexually dimorphic species show differences in their physiology and behavior. Each sex may invest energy in mating and reproduction, rather than immune function at different times of the year since they have different priorities, i.e., securing mating access vs increasing reproductive events. This means that the two sexes may be more susceptible/ less tolerant to parasites at different times of the year. Since this is an observational study, I will be using fecal egg counts (FEC) in terms of eggs per 4 grams (EP4G) as a proxy for susceptibility/tolerance. Furthermore, when individuals have higher parasite FEC, they may need to spend more time grazing and ruminating to ensure enough energy to be able to invest in immune function. That is, higher FEC may lead to individuals spending more time grazing and ruminating as parasites might be siphoning energy and nutrients away from the hosts. I used bighorn sheep, Ovis canadensis, and five of their natural parasites, strongyle, Nematodirus spp., Marshallagia spp., lungworm and Eimeria spp., to investigate seasonality of parasites and host-sex bias and whether higher parasite FEC leads to individuals spending more time grazing. Generalised linear mixed models suggest that parasite FECs are different for male and female bighorn sheep between winter and non-winter seasons. However, the pattern of FECs between the sexes differ based on the parasite group. Strongyle FEC was significantly higher for both sexes during non-winter with male counts being higher than female counts in both seasons. Eimeria spp. count was higher in females compared to males compared in both seasons, but non-winter counts were higher than winter counts. In contrast, FECs for Marshallagia spp., and Nematodirus spp. was significantly higher in females in non-winter, but significantly higher for males in winter months. Following a similar pattern, lungworm larva counts were higher for males during winter, while female counts were lower in winter. Additionally, linear mixed models suggest that bighorn sheep individuals with higher strongyle FEC trended to increase the percent of time that individuals spent grazing, while higher Marshallagia spp. FEC showed a trend in decreasing the percent of time that individuals spent grazing. However, FECs did not affect the time individuals spent ruminating or laying.Item Open Access Risk Factors Influencing Parasite Counts Between- and Within-Litters in Columbian Ground squirrels (Urocitellus columbianus)(2019-03-26) Hammer, Tracey Lynn; Ruckstuhl, Kathreen E.; Neuhaus, Peter; Kutz, Susan J.; Reid, Mary L.The number of parasites carried by a host varies from host to host due to individualities that influence the risk of host exposure to parasites, subsequent invasion of the host and colonization by parasites, and the degree of parasite proliferation within the host. Factors that contribute to differences in risk include variation in host and parasite characteristics as well as in the surrounding environment. Features of the host that may impact parasite count include risk factors such as age, body size, genetic resistances, hormone levels and avoidance behaviors, whereas risk factors derived from the parasite comprises their capacity to find and colonize a new host, and mode of transmission (whether through physical contact, ingestion, inhalation, etc.). Environmental risk factors arise from fluctuations in climate, including microclimate, and the distributions of both host and parasite across the landscape - whether they are in tightly-clumped groupings or diffusely spread. Previous literature has primarily focused on factors that impact the risk of carrying parasites in adult hosts - with the notable exception of clutch size and parasite load. To my knowledge, no study as of yet has placed its central focus on comprehensively exploring risk factors in juvenile hosts with limited previous exposure to parasites. Columbian ground squirrels (Urocitellus columbianus) are used in this study to investigate risk factors to parasitism in juvenile hosts to fleas, lice, and Eimeria, a single-celled intestinal parasite. Columbian ground squirrels offer an ideal study system because offspring are born in environmentally and socially-isolated natal burrows which only the mother enters, making her the sole source of parental care and parasites to her offspring. Two-thirds of litters have multiple paternity, enabling investigation into the role of the father’s genetics. The risk factors tested were separated in two groupings: 1) those that varied between-litters, and 2) those that varied within-litters. Between-litter risk factors included: mother’s condition upon emergence from hibernation, mother’s age, mother’s parasite count, the number of times the natal burrow was changed, litter size, and host density around the natal burrow. Within-litter risk factors included weight, sex, and paternity. Offspring flea counts increased with local host density within 30 m of the nest burrow, and were higher in male offspring, and in offspring with lower body weight. Offspring louse counts increased with host density within 20 m of the natal burrow, and were higher in female offspring and lighter offspring. Eimeria oocyst counts in the feces were higher in offspring that moved natal burrows more frequently. Additional risk factors that had adequate influence to be included in the final models were: for flea count, maternal condition at emergence, for louse count, maternal louse count at weaning and maternal emergence condition, and for Eimeria oocyst count, litter size, mother’s age, and offspring weight. For both fleas and lice, risk increased with host density around the natal burrow; however the effective distance was different: 30 m for fleas and 20 m for lice. While fleas can jump from host-to-host in addition to living off host for short periods of time, lice require direct host-to-host contact which will shorten the effective distance. On the other hand, I propose one of the predominate risk factors influencing high Eimeria oocyst counts is maternal stress. Although stress was not directly measured in this study, offspring that carried more Eimeria had mothers that were older, who had produced larger litters, who had moved natal burrows more often, and who had other closely nesting adult females. All of these could possibly contribute to chronic stress which is known to weaken the immune system, and could additionally lower the ability of the mother to care for her litter and lead to increased risk of Eimeria infection. This study shows that factors which increased risk to parasite infestation in offspring were due to the interaction between the biology of the host and the parasite, as seen with parasite transmission mode for fleas and lice and its relationship to host density, and stress-related immune weakness and Eimeria oocyst count. The re-location of litters to new natal burrows, considered a method of parasite reduction, did not reduce offspring parasite counts. Instead, it appears that parasites infested the natal burrows when the mother prepared them in the weeks after she mated (i.e. during gestation). This made post-mating maternal parasite counts one of the most relevant maternal counts. The other maternal parasite count that consistently had relatively high correlation to offspring parasite count at weaning was maternal count at the same time, reflecting temporally recent transfers of parasites between mothers and their offspring. Sex, weight and yearly environmental conditions were also revealed to be relatively strong risk factors over others such as litter size, number of natal burrow changes, paternity, maternal age, maternal condition, and maternal parasite counts. Investigating offspring in their role as a host gives unique insights into the interactions between hosts and their parasites that are difficult to quantify in adult hosts. Effects stemming from offspring’s mother were found to have stronger effects than those of paternity or litter. Previously well-studied factors, such as litter size, were not found to be strong explanatory factors in this study; instead other factors that were associated with the specific biology of the host and parasite were more relevant, such as host density for fleas and lice, and for Eimeria counts, factors that could induce maternal stress such as neighbouring females, large litters and old age. The more holistic approach in this study, verses a study on the relationship between only a few variables, hopes to provide a clearer impression of the relative weight of risk each factor in determining host parasite count.