The American black bear (ABB) (Ursus americanus) exhibits physiological strategies highly synchronized with the environment. Such strategies enable bears to exploit food resources when available and survive the winter months by hibernating without ingesting food or water. However, there are multiple aspects of ABB hibernation physiology that remain unknown. For instance, there is conflicting evidence on the occurrence of ABB pseudopregnancy (a physiological state in which a non-pregnant bear exhibits progesterone levels similar to gravid bears in the absence of an actual pregnancy). Also, there is little known about postnatal development of cubs or the influence of maternal traits on embryonic implantation and cub growth. Finally, the role of satellite cells (SCs – stem cells able to regenerate muscle fibers) play in maintaining muscle functionality during hibernating remains understudied. Therefore, I aimed to assess these four aforementioned aspects using wild ABBs held temporarily captive at Virginia Tech's Black Bear Research Center (VT-BBRC). The major findings of this dissertation are: 1) I suggest that wild ABBs do not experience pseudopregnancy as a reproductive strategy; 2) interactions between litter size and cub age best described postnatal cub weight dynamics and organ development. Twin cubs were heavier than single and triplet cubs, yet cubs from all litter sizes reached similar weights after mothers began consuming food post hibernation. Single cubs experienced delayed timing in ear, eye, and teeth development compared to other litter sizes; 3) maternal traits such as higher body weight and higher ability to gain weight in the fall are closely associated with earlier timing of embryonic implantation than in leaner females, which gained less weight per day in the fall; and 4) SC ability to generate muscle fibers is increased during ABB hibernation. I propose that maintaining the SCs are an important potential pathway for limiting muscle atrophy during bear hibernation. Understanding pre and postnatal development of ABBs is important for exploring factors related to climate, maternal characteristics, which possibly affect birthing phenology, and fitness of bears experiencing rapid anthropogenic environmental change. Functional aspects of bear muscle conservation are interesting for potentially for elucidating avenues to improve treatments for human metabolic disorders such as muscular dystrophy, sarcopenia, and disuse atrophy. / Ph. D. / The American black bear (ABB) (Ursus americanus) exhibits physiological strategies highly synchronized with the environment. Such strategies enable bears to exploit food resources when available and survive the winter months by hibernating without ingesting food or water. However, there are multiple aspects of ABB hibernation physiology that remain unknown. For instance, there is conflicting evidence on the occurrence of false pregnancies in the ABB. Also, there is little known about postnatal development of cubs or the influence of maternal traits at the beginning of active gestation and cub growth. Finally, the role of satellite cells (SCs – stem cells able to regenerate muscle fibers) play in maintaining muscle functionality during hibernating remains understudied. Therefore, I aimed to assess these four aforementioned aspects using wild ABBs held temporarily captive at Virginia Tech’s Black Bear Research Center (VT - BBRC). The major findings of this dissertation are: 1) I suggest that wild ABBs do not experience false pregnancy as a reproductive strategy; 2) interactions between litter size and age best described postnatal cub weight dynamics and organ development. Twin cubs were heavier than single and triplet cubs, yet cubs from all litter sizes reached similar weights after mothers began consuming food post hibernation. Single cubs experienced delayed timing in ear, eye, and teeth development compared to other litter sizes; 3) maternal characteristics such as higher body weight and higher ability to gain weight in the fall are closely associated with earlier timing of embryonic implantation than in leaner females, which gained less weight per day in the fall; and 4) SC ability to generate muscle fibers is increased during ABB hibernation. I propose that maintaining the SCs are an important potential pathway for limiting muscle atrophy during bear hibernation. Understanding pre and postnatal development of ABBs is important for exploring factors related to climate, maternal characteristics, which possibly affect birthing phenology, and fitness of bears experiencing environmental change. Functional aspects of bear muscle conservation are interesting for potentially for elucidating avenues to improve treatments for human metabolic disorders such as muscular dystrophy, sarcopenia, and disuse atrophy.

Following mass agricultural expansion and deforestation in the late 1800s and early 1900s, American black bear populations (Ursus americanus, hereafter black bear) were low across most of Virginia. The Department of Wildlife Resources (VADWR) and the United States Forest Service worked to rebuild wildlife habitat in the state, leading to recovery of bears. While some aspects of black bear hibernation and foraging ecology have been studied, there remain knowledge gaps on key aspects of black bear biology. Hibernation behavior, for example, is understudied with most knowledge stemming from post-hibernation emergence studies. We used a unique dataset with continuous monitoring of mother bears and their cubs from Virginia Tech's Black Bear Research Center in 2015-2016, to better understand hibernation ecology, mother-cub dynamics, and biological-foster cub dynamics. We found that increased black bear activity levels were driven by both higher temperature and photoperiod, but the onset of hibernation was primarily driven by only temperature. Temperature is projected to rise in VA and rising temperatures regionally could be responsible for increased active behaviors in bears, which could lead to increased human-black bear interactions on the landscape, especially during hibernation onset. We also found that mother bears spend similar amounts of time with biological and foster cubs. Biological cubs did not show more dominance behaviors toward fosters than biological siblings, which we also observed with foster, where they did not continuously display these behaviors towards biological cubs. These results are promising for orphan cub fostering programs in VA and other states and indicate that foster cub litter integration can be successful. Foraging ecology also is challenging to study in black bears because direct observation is generally not possible due to their cryptic nature, closed habitat, or potential danger in observing. We used a dataset from camera collars deployed on 15 bears (8 males, 7 females) in Bath County Virginia in 2018 and 2019 to better understand diet seasonality and to determine habitat and environmental drivers of black bear foraging patterns, particularly on white-tailed deer (Odocoileus virginianus) and invasive plant species. We identified 178 unique diet items to family, genus, or species in videos, much higher numbers than previously reported in the literature, and we found high diet overlap between sexes. Diet composition was primarily influenced by season with higher levels of consumption of herbaceous soft mast in spring, fruit and seed soft mast in summer, and hard mast in fall. Females exhibited more hunting events on deer fawns in spring than males, but males and females consumed similar numbers (28 vs. 24, respectively) via hunting and scavenging combined. Males consumed anthropogenic foods more often than females, particularly when closer to human settlements and males more commonly consumed invasive plant species in spring while females more often consumed insect in spring invasive species in summer. Our results highlight strong seasonally- and subtle sex-mediated differences in black bear diets. We provide information on drivers of diet choices by bears, as well as identify where foraging hotspots on species of interest occur, providing information useful to VADWR in managing increased human-wildlife interactions (and mitigating potential for negative interactions), predator-prey relations, and invasive species spread across the landscape. / Master of Science / American black bears were almost eliminated from Virginia following mass agricultural expansion and deforestation in the late 1800s and early 1900s. The Department of Wildlife Resources (VADWR) and the United States Forest Service worked to rebuild wildlife habitat in the state, leading to recent recovery of bears in VA. However, there are still gaps in our knowledge of black bear ecology and gaining new knowledge will aid in better management of black bears across the state. We used two unique video data sets to study hibernation and foraging (or feeding) ecology to fill important knowledge gaps. To study hibernation behavior, we used a video data set of continuously monitored, temporarily captive mother bears and their cubs held at Virginia Tech's Black Bear Research Center in 2015-2016. We found that black bear activity was driven by both daily temperature and photoperiod (length of daylight), but onset of hibernation was mostly driven by temperature only. With Virginia projected to experience rising, and more variable, temperatures due to climate change, this may mean that bears will stay longer on the landscape in fall, even past the point where vegetation (food) has gone dormant, potentially leading to increased human-black bear interactions as bears seek human foods. We also examined mother-cub interactions and found mother bears did not spend more time with their biological cubs than their fosters (fosters are orphaned black bear cubs arising due to death of mothers) and biological cubs did not show more dominance behaviors (i.e., biting, chasing, or pinning to ground) toward fosters than biological siblings. These are positive results for VADWR's surrogate sow program across the state. Foraging ecology is difficult to study in black bears because direct observation is generally not possible due to their secretive nature, dense habitat, or potential danger in observing. Therefore, traditionally, many studies collect and examine scat (fecal) samples or stomach contents from harvested bears, but these methods may not find diet items that are quickly digested. We used a unique dataset from video camera collars placed on 15 bears in Bath County Virginia in 2018 and 2019. We found some important differences from the literature - our spring diets had higher proportions of deer and soft vegetation (leaves), however the unknown diet items in the literature were high, leading to incomplete or incorrect diet profiles. Diet composition was primarily influenced by season with higher levels of consumption of leafy soft mast in spring, fruit and seed soft mast in summer, and hard mast in fall. Males and females had high dietary overlap and we found that females had more hunting events on deer fawns in spring than males, but overall males and females consumed similar numbers (28 vs. 24, respectively) via hunting and scavenging combined. Males more often consumed human foods than females, while females more often consumed insect species than males. Also, males more commonly consumed invasive species in spring, while females did so in summer. Our results highlight differences in diet content caused by season and subtle differences in diets between sexes. We provide information on drivers of feeding choices bears make and we identify foraging hotspots for deer and invasive species, information useful to VADWR in managing potential human-wildlife interactions, predator-prey relations, and invasive species spread across the landscape.

Bat populations in the eastern United States are currently declining at unprecedented rates as a result of habitat loss, commercial wind energy development, and white-nose syndrome. Effective conservation of these declining populations requires knowledge of several aspects of summer and winter ecology, including daytime habitat use (day-roost selection and social behaviors), nocturnal habitat use (foraging habitat selection, prey selection, and prey abundance), and winter hibernation (torpor) patterns. This dissertation addresses these questions for Rafinesque’s big-eared bat (Corynorhinus rafinesquii), a species of conservation concern in the southeastern United States. Kentucky represents the northern edge of the range of Rafinesque’s big-eared bat, and summer and winter behaviors in Kentucky are likely to differ from what has been observed in southern portion of the range, where available habitats and climate are different. My research occurred in two study areas in Kentucky, Mammoth Cave National Park in central Kentucky, and the Ballard Wildlife Management areas in western Kentucky. This dissertation includes all of the work done in western Kentucky, where I radio-tagged 48 adult big-eared bats and documented daytime and nighttime habitat use. Also included is a portion of the work done in central Kentucky, focusing on hibernation patterns of 14 adult big-eared bats radio-tagged during the winter at Mammoth Cave. Data disseminated in this dissertation provide insights into the summer and winter ecology of Rafinesque’s big-eared bat in Kentucky, and can be used to manage populations threatened by habitat loss and white-nose syndrome.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biology, 2017. / Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Biology; and the Woods Hole Oceanographic Institution), 2017. / Cataloged from PDF version of thesis. / Includes bibliographical references. / Blooms of the dinoflagellate Alexandrium catenella cause paralytic shellfish poisoning syndrome and present an expanding public health threat. They are inoculated through the germination of benthic cysts, a process regulated by internal and environmental factors, most importantly temperature. Less understood is the effect of temperature conditioning on cyst dormancy cycling, which inhibits germination for long periods. This thesis characterizes the temperature-dependence of both dormancy and germination in natural A. catenella cyst populations from Nauset Marsh (Cape Cod, MA, USA), a small estuarine embayment, and relates these processes to the phenology of blooms there. Through laboratory germination assays, it is shown that dormant A. catenella cysts require a quantifiable amount of chilling to exit dormancy and attain quiescence (i.e. become germinable). A series of experiments compares germination rates of quiescent cysts across a range of temperatures through laboratory experiments and field incubations of raw sediment using plankton emergence traps (PETs). Emergence rates of A. catenella germlings measured by PETs increased linearly with temperature and were comparable to germination under constant laboratory conditions. Total emergence fluxes were much lower than expected, suggesting that germination occurs in a much shallower layer of sediments than typically assumed. The results are synthesized to develop a temperature-dependent model to examine the sensitivity of A. catenella bloom phenology to dormancy-breaking by winter chilling. Notably, the chilling-alleviated dormancy model accurately predicted the timing of quiescence (January) and the variable bloom phenology from multiple blooms in Nauset. Once cysts became quiescent and began to germinate, however, temperatures were typically too cold for growth to exceed losses so there was a several-week lag until bloom development. Years with warmer winters and springs had shorter lag periods and thus significantly earlier blooms. Ecologically, dormancy-breaking by a chilling threshold is advantageous because it prevents the mismatch between conditions that are favorable for germination but not for the formation of large blooms. Synchronized germination after winter chilling also promotes promotes efficient conversion from the cyst seedbed to the spring bloom inoculum. The dormancy mechanism characterized here may be present in other cyst-forming dinoflagellates, but there is likely plasticity that reflects the temperature regime of each habitat. / by Alexis Dal Fischer. / Ph. D.

The range of a species often extends across a diverse landscape, necessitating that individuals make different movement and habitat decisions, despite consistent food and shelter requirements. Great Basin gophersnakes (Pituophis catenifer deserticola) are threatened in Canada, where they occur at the northern extent of their range in southern interior river valleys of British Columbia such as the Okanagan Valley. I followed 39 radio-transmittered adult gophersnakes at four sites in the Okanagan, to obtain information on life history, movement and range patterns, and habitat use. Habitat selection and movement patterns exhibited by gophersnakes differed between study sites, sexes, and months, indicating that snake choice varies depending on resources and life history traits. Despite these fine-grain differences, males moved more than females in the spring. In addition to this, females moved more than males in the summer and fall. Differences in movement and range were apparent among the study sites. Habitat selection differed by study site, however rock-outcrops were consistently selected overall. Microhabitat selection varied, but retreat sites including logs, rocks, and holes in the ground, were consistently located closer than random. Hibernation sites in the south Okanagan were in rock features, while in the north Okanagan a good proportion were in rodent burrows in hillsides. Hibernation site fidelity was low, and annual reproduction was common. Oviposition sites were on south-facing slopes of moderate grade with little to moderate grass cover. Three ecdysis periods were observed when most or all transmitter-equipped snakes shed their skin. These findings will be very valuable to species conservation goals in British Columbia when developing guidelines on the habitats and sizes of areas to protect. With an iii understanding of the movement and ranges patterns exhibited by individuals, the area required to sustain a healthy population of gophersnakes can be determined. Knowledge of the habitats and microhabitats gophersnakes select makes it possible to identify and protect important areas at sites known to contain gophersnakes, including the Vaseux, Ripley, and Vernon study sites. Characterization of hibernation and oviposition sites allows surveys to identify these areas in locations that may support gophersnakes. Finally, identification of the timing of various important life history behaviours means human disturbance can be avoided during mating and oviposition periods, especially on sites such as Vernon, where land is used for multiple purposes.

The range of a species often extends across a diverse landscape, necessitating that individuals make different movement and habitat decisions, despite consistent food and shelter requirements. Great Basin gophersnakes (Pituophis catenifer deserticola) are threatened in Canada, where they occur at the northern extent of their range in southern interior river valleys of British Columbia such as the Okanagan Valley. I followed 39 radio-transmittered adult gophersnakes at four sites in the Okanagan, to obtain information on life history, movement and range patterns, and habitat use. Habitat selection and movement patterns exhibited by gophersnakes differed between study sites, sexes, and months, indicating that snake choice varies depending on resources and life history traits. Despite these fine-grain differences, males moved more than females in the spring. In addition to this, females moved more than males in the summer and fall. Differences in movement and range were apparent among the study sites. Habitat selection differed by study site, however rock-outcrops were consistently selected overall. Microhabitat selection varied, but retreat sites including logs, rocks, and holes in the ground, were consistently located closer than random. Hibernation sites in the south Okanagan were in rock features, while in the north Okanagan a good proportion were in rodent burrows in hillsides. Hibernation site fidelity was low, and annual reproduction was common. Oviposition sites were on south-facing slopes of moderate grade with little to moderate grass cover. Three ecdysis periods were observed when most or all transmitter-equipped snakes shed their skin. These findings will be very valuable to species conservation goals in British Columbia when developing guidelines on the habitats and sizes of areas to protect. With an iii understanding of the movement and ranges patterns exhibited by individuals, the area required to sustain a healthy population of gophersnakes can be determined. Knowledge of the habitats and microhabitats gophersnakes select makes it possible to identify and protect important areas at sites known to contain gophersnakes, including the Vaseux, Ripley, and Vernon study sites. Characterization of hibernation and oviposition sites allows surveys to identify these areas in locations that may support gophersnakes. Finally, identification of the timing of various important life history behaviours means human disturbance can be avoided during mating and oviposition periods, especially on sites such as Vernon, where land is used for multiple purposes.

CAPES / Durante a dormência, as plantas de clima temperado cessam temporariamente o crescimento visível. No caso da macieira sabe-se que a temperatura é o fator ambiental que mais influencia a dormência. A planta necessita de baixas temperaturas para induzir a entrada e posteriormente a saída da dormência, para então retomar o crescimento vegetativo. Sabe-se que quando não ocorre acúmulo suficiente de frio, as plantas apresentam crescimento errático, com brotação ocorrendo predominantemente na porção distal dos ramos, comprometendo a brotação satisfatória. No entanto, há pouca informação sobre o metabolismo destes carboidratos e sua relação com a dormência de plantas em condições de inverno ameno. Contudo o objetivo deste trabalho foi avaliar as diferenças biológicas e bioquímicas entre as porções distal e proximal de ramos de macieira que influenciam a acrotonia. De abril a outubro dos anos de 2012, 2013 e 2014, foram coletados ramos e esporões de três cultivares de macieira (Eva, Galaxy e Fuji Suprema) cultivadas em um pomar comercial no município de Plamas-PR. Para avaliar a intensidade da dormência em gemas vegetativas foi realizado o teste de estacas de uma só gema, e o teste de Tabuenca para as gemas florais. Variáveis bioquímicas também foram avaliadas como o teor de proteínas solúveis; atividade de alfa-amilase; açúcares (glicose, frutose, sacarose e sorbitol); amido e umidade. De forma geral as cultivares apresentaram tempo médio de brotação (TMB) menores do que em clima temperado. A porcentagem de brotação manteve-se alta na maioria das coletas para as três cultivares. O teste de Tabuenca confirmou a precocidade da cultivar Eva e mostrou comportamento muito semelhante entre a ‘Galaxy’ e a ‘Fuji Suprema’. Além disso foi observado um intervalo muito curto entre a saída da endodormência em condições de forçagem e em condição de campo. A umidade ponderal variou conforme o padrão da temperatura em cada ano, sendo que em 2013, ano de maior acúmulo de frio a umidade ponderal apresentou os menores valores para todas as cultivares. Em 2013 a tendência de aumento da atividade da alfa-amilase e no teor de proteína coincidiram com o menor valor de TMB. A glicose e frutose apresentaram comportamento muito semelhantes entre si durante as observações. O teor de sacarose variou de ano para ano, não apresentando um padrão fixo. O sorbitol, açúcar mais abundante no xilema, tende a ser mais constante durante a dormência com leve tendência de redução próximo à brotação. O teor de amido tende a diminuir com os primeiros acúmulos de horas frio, no entanto frequentemente sofre ressíntese, devido às ondas de calor comuns no inverno. Existe diferenças entre as porções dital e proximal dos ramos para todas as variáveis analisadas, com teor de carboidrato, atividade enzimática, proteínas e umidade predominantemente maiores na porção distal dos ramos, com algumas exceções pontuais. Isso pode estar associado à ocorrência de acrotonia em macieiras. As plantas avaliadas parecem não entrar em dormência profunda em condição de inverno ameno, tendo seu metabolismo muito sujeito às oscilações de temperatura. O metabolismo das plantas tende a mudar de ano para ano de acordo com o padrão do inverno em cada ano. / During dormancy, temperate plants temporarily stops visible growth. In apple trees, it is known that temperature is the environmental factor that most influences dormancy. The plant requires low temperatures to induce input and then to output endodormancy, thus resumption vegetative grow. It is known that when there isn’t sufficient chilling accumulation, plants present erratic growth, with budbreak occurring predominantly in the distal portion of the branches, compromising the satisfactory budbreak. However, there is little information on the metabolism of these carbohydrates and their relationship to plant dormancy in subtropical humid climates. This work aimed to evaluate the biological and biochemical differences between the distal and proximal portions of apple tree branches that influence acrotonia. From April to October of 2012, 2013 and 2014, branches and spurs of three apple cultivars (Eva, Galaxy and Fuji Suprema) were harvested in a commercial orchard in Palmas-PR. In order to evaluate the dormancy intensity in vegetative and floral buds, single bud cuttings test and Tabuenca test were carried out, respectively. Biochemical variables were also evaluated such as soluble protein content; Alpha-amylase activity; Soluble sugars (glucose, fructose, sucrose and sorbitol); Starch and water content. In general, the cultivars showed the Mean Time to Budbrst (MTB) lower than in temperate climate. The budburst percentage remained high in most of the observation dates for the three cultivars. The Tabuenca test confirmed the precocity of the cultivar Eva and showed very similar behavior between 'Galaxy' and 'Fuji Suprema'. In addition, a very short interval between the endodormancy output under forcing conditions and in field condition was observed. The water content varied according to the temperature pattern in each year, and in 2013, the year of greatest cold accumulation, the lowest values for all cultivars were observed. In 2013, the trend of increased alpha-amylase activity and protein content coincided with the lower value of MTB. Glucose and fructose presented very similar behavior among themselves during the observations. The sucrose content varied from year to year and did not present a fixed pattern. Sorbitol, sugar most abundant in the xylem, tends to be more constant during dormancy with a slight reduction tendency close to budding. The starch content tends to decrease with the first chilling accumulations, however it often undergoes resynthesis due to the heat waves common in winter. There are differences between the distal and proximal portions of the branches for all variables analyzed, with carbohydrate content, enzymatic activity, proteins and humidity predominantly larger in the distal portion of the branches, with some occasional exceptions. This may be associated with the occurrence of acrotonia in apple trees. The evaluated apple trees do not appear to fall into deep endodormancy in a mild winter condition, their metabolism seems to be very subject to temperature oscillations. Plant metabolism tends to change from year to year according to the winter pattern in each year.

The range of a species often extends across a diverse landscape, necessitating that individuals make different movement and habitat decisions, despite consistent food and shelter requirements. Great Basin gophersnakes (Pituophis catenifer deserticola) are threatened in Canada, where they occur at the northern extent of their range in southern interior river valleys of British Columbia such as the Okanagan Valley. I followed 39 radio-transmittered adult gophersnakes at four sites in the Okanagan, to obtain information on life history, movement and range patterns, and habitat use. Habitat selection and movement patterns exhibited by gophersnakes differed between study sites, sexes, and months, indicating that snake choice varies depending on resources and life history traits. Despite these fine-grain differences, males moved more than females in the spring. In addition to this, females moved more than males in the summer and fall. Differences in movement and range were apparent among the study sites. Habitat selection differed by study site, however rock-outcrops were consistently selected overall. Microhabitat selection varied, but retreat sites including logs, rocks, and holes in the ground, were consistently located closer than random. Hibernation sites in the south Okanagan were in rock features, while in the north Okanagan a good proportion were in rodent burrows in hillsides. Hibernation site fidelity was low, and annual reproduction was common. Oviposition sites were on south-facing slopes of moderate grade with little to moderate grass cover. Three ecdysis periods were observed when most or all transmitter-equipped snakes shed their skin. These findings will be very valuable to species conservation goals in British Columbia when developing guidelines on the habitats and sizes of areas to protect. With an iii understanding of the movement and ranges patterns exhibited by individuals, the area required to sustain a healthy population of gophersnakes can be determined. Knowledge of the habitats and microhabitats gophersnakes select makes it possible to identify and protect important areas at sites known to contain gophersnakes, including the Vaseux, Ripley, and Vernon study sites. Characterization of hibernation and oviposition sites allows surveys to identify these areas in locations that may support gophersnakes. Finally, identification of the timing of various important life history behaviours means human disturbance can be avoided during mating and oviposition periods, especially on sites such as Vernon, where land is used for multiple purposes. / Irving K. Barber School of Arts and Sciences (Okanagan) / Biology, Department of (Okanagan) / Graduate

No description available.

Les mammifères alpins sont vulnérables aux changements climatiques car ils sont confinés à une certaine altitude. Toutefois, des adaptations physiologiques et comportementales chez certaines espèces d’animaux fouisseurs pourraient, en partie, atténuer les impacts négatifs des changements climatiques. En effet, chez les animaux fouisseurs qui hibernent, le fait d’avoir recours à la torpeur en hiver en plus d’avoir accès à des terriers souterrains permet aux individus de réduire leur exposition aux conditions extérieures lorsqu’elles sont défavorables. J’ai étudié les liens entre les facteurs environnementaux et les variations interannuelles de la masse corporelle et de la survie chez les adultes d’une population de marmottes des Rocheuses. Mon étude utilise des données qui ont été récoltées pendant 14 ans à Caw Ridge en Alberta. J’ai émis l’hypothèse que la variation interannuelle dans les conditions environnementales au printemps, à l’été et en hiver déterminerait la masse corporelle des individus pendant l’été en plus de la survie annuelle via des effets directs sur la qualité et la disponibilité des ressources alimentaires. J’ai aussi prédit que la masse à la fin de la saison d’activité serait l’un des principaux déterminant de la survie annuelle. Mes résultats démontrent un effet positif des printemps hâtifs sur le gain de masse estival et la survie annuelle. J’observe aussi que la masse à l’émergence des marmottes qui ont connu des hivers froids et rigoureux est 47% inférieure à celle des marmottes qui ont connu des hivers plus doux. Toutefois, les marmottes qui émergent avec une masse plus faible aux printemps suivants des hivers plus rigoureux ont un gain de masse plus important pendant l’été. Ainsi, à la fin de l’été, elles atteignent une masse similaire à celles qui ont une masse plus élevée à l’émergence suivant un hiver plus doux. Cela suggère que les individus adoptent une stratégie d’allocation des ressources qui leur permet de maximiser leur gain de masse estival afin de survivre pendant la prochaine période d’hibernation. Cette capacité des marmottes à maximiser leur gain de masse estival contribue probablement à expliquer le fait que je n’ai pas observé d’effets de la masse à la fin de la saison active sur la survie annuelle. Bien que les adultes devraient avoir des réponses tamponnées aux changements environnementaux comparés aux juvéniles, notre étude suggère que la masse corporelle et la survie des adultes peuvent être considérablement affectées par les conditions environnementales et que les changements prévus dans les conditions climatiques pourraient avoir des effets sur les espèces d’animaux fouisseurs qui hibernent en milieux alpins