Murray M. Humphries's research while affiliated with McGill University and other places

Publications (176)

Article
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Snowshoe hare cycles are one of the most prominent phenomena in ecology. Experimental studies point to predation as the dominant driving factor, but previous experiments combining food supplementation and predator removal produced unexplained multiplicative effects on density. We examined the potential interactive effects of food limitation and pre...
Article
Traditional food systems based on harvest from the local environment are fundamental to the well-being of many communities, but their security is challenged by rapid socio-ecological change. We synthesized literature and data describing how a fundamental form of biodiversity, animal body size, contributes to the security of traditional food systems...
Article
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The energetic consequences of body size, behaviour, and fine-scale environmental variation remain understudied, particularly among free-ranging carnivores, due to logistical and methodological challenges of studying them in the field. Here, we present novel activity, heart rate, and metabolic data on free-ranging Canada lynx (Lynx canadensis Kerr,...
Article
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Previous research demonstrated that cities are similar to individual mammals in their relationship between the rate of energy use for heating and outdoor air temperature (Ta). At Tas requiring heating of indoor living spaces, the energy-Ta plot of a city contains information on city-wide thermal insulation (I), making it possible to quantify city-w...
Article
Winter conditions impose dramatic constraints on temperate, boreal, and polar ecosystems, and shape the abiotic and biotic interactions underpinning these systems. At high latitudes, winter can last longer than the growing season and may have a disproportionately large impact on organisms and ecosystems. Even so, our understanding of the ecological...
Article
Communicating value across the pluralities of Indigenous Peoples’ food systems requires attention to economy and environment, food and wildlife, and the health of the people and that of the land. Valuation of distinct entities is always difficult but often essential to describe collective wealth and well-being, to quantify trade-offs, and to consid...
Preprint
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Climate warming is causing asynchronies between animal phenology and environments. Mismatched traits, like coat color change mismatched with snow, can decrease survival. However, coat change does not serve a singular adaptive benefit of camouflage, and alternate coat change functions may confer advantages that supersede mismatch costs. We found tha...
Article
Food availability and temporal variation in predation risk are both important determinants of the magnitude of antipredator responses, but their effects have rarely been examined simultaneously, particularly in wild prey. Here, we determine how food availability and long‐term predation risk affect antipredator responses to acute predation risk by m...
Article
Characterizing variation in predator behaviour and, specifically, quantifying kill rates is fundamental for parameterizing predator–prey and food web models. Yet, current methods for recording kill rates of free‐ranging predators, particularly those that consume small‐bodied (<2 kg) prey, present a number of associated challenges. In this paper, we...
Article
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Frozen winters define life at high latitudes and altitudes. However, recent, rapid changes in winter conditions have highlighted our relatively poor understanding of ecosystem function in winter relative to other seasons. Winter ecological processes can affect reproduction, growth, survival, and fitness, whereas processes that occur during other se...
Article
The recent world-wide loss of seagrasses, which are critical components of coastal ecosystems, has ignited an effort among scientists and resource managers to develop effective monitoring tools. Although Landsat time-series is considered one of the most cost-effective options for monitoring landscapes, its application to monitor seagrasses remains...
Chapter
Global social and economic changes, alongside climate change, are affecting the operating environment for agriculture, leading to efforts to increase production and yields, typically through the use of agrochemicals like pesticides and fertilizers, expanded irrigation, and changes in seed varieties. Intensification, alongside the expansion of agric...
Article
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The Canadian Mountain Network (CMN) launched in 2019 as a new national research network dedicated to the resilience and health of mountain peoples and places. Supported by complementary training, knowledge mobilization, and networking programs, CMN's research program represents a once-in-a-generation opportunity to identify and address mountain kno...
Article
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Canada lynx (Lynx canadensis) and snowshoe hares (Lepus americanus) form a keystone predator–prey cycle that has large impacts on the North American boreal forest vertebrate community. Snowshoe hares and lynx are both well-suited for snowy winters, but climate change-associated shifts in snow conditions could lower hare survival and alter cyclic dy...
Article
Long-term studies of wild animals provide the opportunity to investigate how phenotypic plasticity is used to cope with environmental fluctuations, and how the relationships between phenotypes and fitness can be dependent upon the ecological context. Most previous studies have only investigated life history plasticity in response to changes in temp...
Article
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The pace-of-life syndrome hypothesis posits that personality traits (i.e. consistent individual differences in behaviour) are linked to life history and fitness. Specifically, fast-paced individuals are predicted to be proactive (i.e. active and aggressive) with an earlier age at first reproduction, a shorter life span and higher fecundity than slo...
Article
Hibernators suppress physiological processes when expressing torpor, yet little is known about the effects of torpor on male reproductive physiology. Studies of hibernating mammals suggest that deep torpor negatively impacts spermatogenesis and that transitions between torpor and euthermic arousals increase cellular oxidative stress, with potential...
Article
Organisms survive environmental variation by combining homeostatic regulation of critical states with allostatic variation of other traits, and species differences in these responses can contribute to coexistence in temporally‐variable environments. In this paper, we simultaneously record variation in three functional traits – body temperature (Tb)...
Article
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Social-ecological and biocultural systems connect people to their environment at the intersection of nature and culture. The harvest of local wildlife for human consumption is critically important to the food security of the world's Indigenous peoples and to the conservation of biodiversity, either as a driver of biodiversity loss or of biodiversit...
Article
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Animals switch between inactive and active states, simultaneously impacting their energy intake, energy expenditure and predation risk, and collectively defining how they engage with environmental variation and trophic interactions. We assess daily activity responses to long‐term variation in temperature, resources and mating opportunities to exami...
Article
Protective clothing is essential for human existence in the Arctic, and caribou-skin clothing has played a pivotal role for millennia. Although people with northern experience often extol caribou-skin clothing, few scientific studies have investigated its properties. We used infrared thermal imaging in a pilot study to compare authentic caribou-ski...
Article
Effective wildlife management and conservation require knowledge of distribution, sex composition, and age structure of a population. We explored the distribution of the Baffin Bay narwhal (Monodon monoceros) population in August 2013 by documenting sex and age distribution across the Canadian Arctic Archipelago covering 2,317,152 km2. For 6,314 na...
Preprint
Full-text available
The pace of life syndrome hypothesis posits that personality traits (i.e., consistent individual differences in behaviour) are linked to life history and fitness. Specifically, fast-paced individuals are predicted to be proactive (i.e., active and aggressive) with an earlier age at first reproduction, a shorter lifespan, and a higher fecundity than...
Article
Intraguild (IG) interactions are common among mammalian carnivores, can include intraguild predation (IGP) and interspecific killing (IK), and are often asymmetrical, where a larger more dominant species (IGpredator) kills a smaller one (IGprey). According to ecological theory, the potential for an IGpredator and IGprey to coexist depends on whethe...
Article
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Technological miniaturization is driving a biologging revolution that is producing detailed and sophisticated techniques of assessing individual behavioral responses to environmental conditions. Among the many advancements this revolution has brought is an ability to record behavioral responses of nocturnal, free-ranging species. Here, we combine c...
Article
For territorial species, the ability to be behaviourally plastic in response to changes in their social environment may be beneficial by allowing individuals to mitigate conflict with conspecifics and reduce the costs of territoriality. Here we investigated whether North American red squirrels, Tamiasciurus hudsonicus, are able to minimize costs of...
Article
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The miniaturization and affordability of new technology is driving a biologging revolution in wildlife ecology with use of animal‐borne data logging devices. Among many new biologging technologies, accelerometers are emerging as key tools for continuously recording animal behavior. Yet a critical, but under‐acknowledged consideration in biologging...
Article
Fisher's principle explains that population sex ratio in sexually reproducing organisms is maintained at 1 : 1 owing to negative frequency-dependent selection, such that individuals of the rare sex realize greater reproductive opportunity than individuals of the more common sex until equilibrium is reached. If biasing offspring sex ratio towards th...
Preprint
Full-text available
For territorial species, the ability to be behaviourally plastic in response to changes in their social environment may be beneficial by allowing individuals to mitigate conflict with conspecifics and reduce the costs of territoriality. Here we investigated whether North American red squirrels (Tamiasciurus hudsonicus) were able to minimize costs o...
Article
Territoriality arises when the benefits of resources exceed the costs of defending them. The dear enemy phenomenon, where familiar territorial neighbours refrain from intruding on one another and mutually reduce their defensive efforts, allows for reduction of these costs but requires discrimination between conspecifics. We hypothesized that territ...
Preprint
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In many species, territory defense is thought to be one of the primary functions of acoustic communication. North American red squirrels are a territorial species in which 'rattles' have long been thought to be the principal signal communicating territory ownership. These vocalizations have been assumed to deter intruders, thus reducing energy cost...
Preprint
Full-text available
Territoriality arises when the benefits of resources exceed the costs of defending them. The dear enemy phenomenon, where familiar territorial neighbours refrain from intruding on one another and mutually reduce their defensive efforts, allows for reduction of these costs but requires discrimination between conspecifics. We hypothesized that territ...
Article
Identification of critical habitat is central to major conservation laws protecting endangered species in North America and around the world. Yet the actual ecological research that is required to identify which habitats are critical to the survival or recovery of species is rarely discussed and poorly documented. Here we quantitatively assess the...
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https://deepblue.lib.umich.edu/bitstream/2027.42/143645/1/ecy2158-sup-0002-AppendixS2.pdf
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Population and species management of long-lived species such as narwhal (Monodon monoceros) require long-term ecological monitoring programs to provide baseline information on population structure and dynamics. The success of such programs is dependent on the repeatability of the methods. Here, we propose a dichotomous key to identify narwhal newbo...
Article
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Background Our understanding of gut microbiota has been limited primarily to findings from human and laboratory animals, but what shapes the gut microbiota in nature remains largely unknown. To fill this gap, we conducted a comprehensive study of gut microbiota of a well-studied North American red squirrel (Tamiasciurus hudsonicus) population. Red...
Article
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In many species, territory advertisement is thought to be one of the primary functions of acoustic communication. North American red squirrels are a territorial species in which 'rattles' have long been thought to be the principal signal communicating territory ownership. These vocalizations have been assumed to deter intruders, thus reducing energ...
Poster
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Lancaster Sound us the largest national marine conservation area (NMCA) in the Canadian Arctic. There is a need to obtain more knowledge on species present in the NMCA such as narwhals in order order to best manage the NMCA . The narwhal (Monodon monoceros L.) is a medium-sized odontocete living strictly in Arctic waters. Describing the distributio...
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The age trajectory of reproductive performance of many iteroparous species features an early - life increase in performance followed by a late - life senescent decline. The largest contribution of lifetime reproductive success is therefore gained at the age at which reproductive performance peaks. Using long term data on North American red squirrel...
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Studies of the behaviour of diving animals usually focus on either individual dives or surface group activities, but these complementary observations are seldom combined in the same study. We here study the summer (June-October) behaviour of St. Lawrence Estuary belugas (Delphinapterus leucas (Pallas, 1776)) by combining fine-scale individual divin...
Article
Seasonality is a critically important aspect of environmental variability, and strongly shapes all aspects of life for organisms living in highly seasonal environments. Seasonality has played a key role in generating biodiversity, and has driven the evolution of extreme physiological adaptations and behaviors such as migration and hibernation. Fluc...
Article
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From a trophic perspective, a seasonal increase in air temperature and photoperiod propagates as bottom-up pulse of primary production by plants, secondary production by herbivores, and tertiary production by carnivores. However, food web seasonality reflects not only abiotic variation in temperature and photoperiod, but also the composition of the...
Article
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Individual natal dispersal behaviour is often difficult to predict as it can be influenced by multiple extrinsic and intrinsic factors. Individual differences in personality have been shown to be an important correlate of dispersal behaviour. However, the relationships between personality traits and dispersal are often inconsistent within and acros...
Article
Understanding the benefits and outcomes of Canada's public investment in Arctic science and associated community–researcher partnerships represents a significant challenge for government. This paper presents a capital assets-based approach to conceptualising northern research partnership development processes and assessing the potential outcomes. B...
Article
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Interactions with conspecifics are an important aspect of an individual's environment. Although it is well known that the presence of conspecifics can have important effects on behaviour, in general it is also now acknowledged that the composition of the social environment can vary, and that this variation may have profound effects on individual be...
Article
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Recent research is revealing incredible diversity in the thermoregulatory patterns of wild and captive endotherms. As a result of these findings, classic thermoregulatory categories of 'homeothermy', 'daily heterothermy', and 'hibernation' are becoming harder to delineate, impeding our understanding of the physiological and evolutionary significanc...
Article
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Individuals often interact more closely with some members of the population (e.g. offspring, siblings or group members) than they do with other individuals. This structuring of interactions can lead to multilevel natural selection, where traits expressed at the group-level influence fitness alongside individual-level traits. Such multilevel selecti...
Preprint
Full-text available
Individuals often interact more closely with some members of the population (e.g. offspring, siblings or group members) than they do with other individuals. This structuring of interactions can lead to multilevel natural selection, where traits expressed at the group-level influence fitness alongside individual-level traits. Such multilevel selecti...
Article
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Kin recognition can facilitate kin selection and may have played a role in the evolution of sociality. Red squirrels (Tamiasciurus hudsonicus) defend territories using vocalizations known as rattles. They use rattles to discriminate kin, though the mechanism underlying this ability is unknown. Our objective was to distinguish between the mechanisms...
Chapter
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Mammals, like many animals, must regulate their body temperature to survive and thrive. As a result, climate affects mammals both directly (i.e. through hypo- and hyperthermia) and indirectly (i.e. through their resources, competitors, and predators). These indirect effects are so strong they frequently supersede the direct effects of climate. When...
Article
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Given fundamental energetic trade-offs among growth, maintenance, and reproduction, individual differences in energy-saving should have consequences for survival and reproductive success. Many endotherms use periodic heterothermy to reduce energy and water requirements and individual variation in heterothermy should have fitness consequences. Howev...
Article
On Page 668, the reported isotope turnover times of 3.4, [ 4 _ T D $ D I F F ] 3.9, and 8.7 months for plasma, organs[ 5 _ T D $ D I F F ] , and muscle of a hypothetical 2 kg vertebrate were erroneously referred to as times to 'full isotopic turnover' when these values should have been reported as 'double the isotopic half-life' (the isotopic half-...
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Many have argued that monitoring conducted exclusively by scientists is insufficient to address ongoing environmental challenges. One solution entails the use of mobile devices in broadly-applied participatory monitoring (PM) programs. But how digital data entry affects programs with varying levels of stakeholder participation, from volunteer data...
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Time allocation by lactating mammals is a reconciliation of often opposing nutritional and thermal demands of both the offspring and mother. Here we test the hypothesis that nest attendance patterns of lactating red squirrels (Tamiasciurus hudsonicus) vary with environmental and biological traits that relate to the thermoregulation of mothers and t...
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An important component of northern research in Canada has been a strong emphasis on local participation. However, the policy and permit landscape for community participation therein is heterogeneous and presents specific challenges in promoting effective partnerships between researchers and local participants. We conducted a survey of northern rese...
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Temporal variation characterizes many of Earth's ecosystems. Despite this, little is known about how food webs respond to regular variation in time, such as occurs broadly with season. We argue that season, and likely any periodicity, structures food webs along a temporal axis in an analogous way to that previously recognized in space; predators sh...
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The ability to discriminate among individuals, or among classes of individuals, can provide animals with important fitness benefits. Although several mechanisms for discrimination are possible, most require animals to show stable phenotypic variation that reflects their identity or their membership in a particular class (e.g. sex, mate, kin). For t...
Article
Both juvenile and adult animals display stable behavioural differences (personality), but lifestyles and niches may change as animals mature, raising the question of whether personality changes across ontogeny. Here, we use a wild population of red squirrels to examine changes in activity and aggression from juvenile to yearling life stages. Person...
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Genetic variation in fitness is required for the adaptive evolution of any trait but natural selection is thought to erode genetic variance in fitness. This paradox has motivated the search for mechanisms that might maintain a population's adaptive potential. Mothers make many contributions to the attributes of their developing offspring and these...
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Most empirical attempts to explain the evolution of parental care have focused on its costs and benefits (i.e., fitness consequences). In contrast, few investigations have been made of the other necessary prerequisite for evolutionary change, inheritance. Here, we examine the fitness consequences and heritability (h(2) ) of a post-weaning parental...