Esther Lévesque

• PhD
• Professor (Full) at University of Quebec at Trois-Rivieres

The Arctic is warming faster than anywhere else on Earth, placing tundra ecosystems at the forefront of global climate change. Plant biomass is a fundamental ecosystem attribute that is sensitive to changes in climate, closely tied to ecological function, and crucial for constraining ecosystem carbon dynamics. However, the amount, functional compos...

Population fluctuations of lemmings in the High Arctic appear to be driven by predator–prey interactions. However, lemming grazing can sometimes have a strong impact on the vegetation during population peaks, suggesting a possible role of plant–herbivore interactions. We use a large-scale experiment where predators were excluded to investigate whet...

Northern regions are warming faster than the rest of the globe. It is difficult to predict ecosystem responses to warming because the thermal sensitivity of their biophysical components varies. Here, we present an analysis of the authors’ expert judgment regarding the sensitivity of six ecosystem components – permafrost, peatlands, lakes, snowpack,...

Aim Arctic plants survived the Pleistocene glaciations in unglaciated refugia. The number, ages, and locations of these refugia are often unclear. We use high‐resolution genomic data from present‐day and Little‐Ice‐Age populations of Arctic Bell‐Heather to re‐evaluate the biogeography of this species and determine whether it had multiple independen...

Arctic ecosystems are undergoing rapid changes, including increasing disturbance by herbivore populations, which can affect plant species coexistence and community assemblages. Although the significance of mosses in Arctic wetlands is well recognized, the long‐term influence of medium‐sized herbivores on the composition of moss communities has rece...

Plant biomass is a fundamental ecosystem attribute that is sensitive to rapid climatic changes occurring in the Arctic. Nevertheless, measuring plant biomass in the Arctic is logistically challenging and resource intensive. Lack of accessible field data hinders efforts to understand the amount, composition, distribution, and changes in plant biomas...

We present the history of research activities at the Bylot Island Field Station of the Centre d’études nordiques, a hotspot of biodiversity in the Canadian Arctic. Intensive wildlife studies started at the station in the late 1980s, initially focussing on greater snow goose ecology and its impacts on the tundra vegetation. Since then, studies have...

Surface conditions are known to mediate the impacts of climate warming on permafrost. This calls for a better understanding of the environmental conditions that control the thermal regime and the depth of the active layer, especially within heterogeneous tundra landscapes. This study analyzed the spatial relationships between thaw depths, ground su...

Aim: Arctic plants survived the Pleistocene glaciations in unglaciated refugia, but the number of these refugia is often unclear. We use high-resolution genomic data from present-day and Little-Ice-Age populations of Arctic White Heather (Cassiope tetragona) to re-evaluate the biogeography of this species and determine whether it had multiple indep...

Climate change is leading to species redistributions. In the tundra biome, shrubs are generally expanding, but not all tundra shrub species will benefit from warming. Winner and loser species, and the characteristics that may determine success or failure, have not yet been fully identified. Here, we investigate whether past abundance changes, curre...

Northern ecosystems are among the most exposed to warming and their responses are difficult to anticipate due to the variable sensitivity of their biophysical components. Using an analysis based on expert assessment, we investigated heterogeneity in the sensitivity to climate-driven state shifts across the vast northern landscape, from the boreal t...

Evidence points out that increasing plant productivity associated with greater erect shrub abundance alters soil organic carbon (SOC) stocks in the Arctic. However, the underlying plant economic traits remain poorly examined, which limits our understanding of plant–environment interactions driving tundra carbon cycling. We explored how erect shrub...

It is of prime importance to understand feedbacks due to the release of carbon (C) stored in permafrost soils (permafrost‐climate feedback) and direct impacts of climatic variations on permafrost dynamics therefore received considerable attention. However, indirect effects of global change, such as the variation in soil nutrient availability and gr...

Climate change is leading to a species redistributions. In the tundra biome, many shrub species are expanding into new areas, a process known as shrubification. However, not all tundra shrub species will benefit from warming. Winner and loser species (those projected to expand and contract their ranges, and/or those that have increased or decreased...

Arctic vegetation cover has been increasing over the last 40 years, which has been attributed mostly to increases in temperature. Yet, the temporal dimension of this greening remains overlooked as it is often viewed as a monotonic trend. Here, using 11-year long rolling windows on 30 m resolution Landsat data, we examined the temporal variations in...

Questions Plant greening phenology is a key response trait that drives numerous ecosystem functions such as carbon storage and flowering. Plant communities with a diversity of phenology responses could show a longer greening season due to more complete occupation of the temporal window available for growth. However, it is unclear how species compos...

Nutrient availability for tundra vegetation could change drastically due to increasing temperatures and frequency of nitrogen deposition in the Arctic. Few studies have simultaneously examined the response of plant communities to these two pressures over a long period. This study aims to assess which driver between increasing nitrogen (N) and phosp...

Snow is the dominant form of precipitation and the main cryospheric feature of the High Arctic (HA) covering its land, sea, lake and river ice surfaces for a large part of the year. The snow cover in the HA is involved in climate feedbacks that influence the global climate system, and greatly impacts the hydrology and the ecosystems of the coldest...

Background The functioning of ecosystems is highly variable through space and time. Climatic and edaphic factors are forcing ecological communities to converge, whereas the diversity of plant assemblages dampens these effects by allowing communities’ dynamics to diverge. This study evaluated whether the growing season phenology of wetland plant com...

The relative contribution of bryophytes to plant diversity, primary productivity, and ecosystem functioning increases towards colder climates. Bryophytes respond to environmental changes at the species level, but because bryophyte species are relatively difficult to identify, they are often lumped into one functional group. Consequently, bryophyte...

Litter decomposition is a key process for carbon and nutrient cycling in terrestrial ecosystems and is mainly controlled by environmental conditions, substrate quantity, and quality as well as microbial community abundance and composition. In particular, the effects of climate and atmospheric nitrogen (N) deposition on litter decomposition and its...

Observations of changes in phenology have provided some of the strongest signals of the effects of climate change on terrestrial ecosystems. The International Tundra Experiment (ITEX), initiated in the early 1990s, established a common protocol to measure plant phenology in tundra study areas across the globe. Today, this valuable collection of phe...

Climate warming is expected to positively alter upward and poleward treelines which are controlled by low temperature and a short growing season. Despite the importance of treelines as a bioassay of climate change, a global field assessment and posterior forecasting of tree growth at annual scales is lacking. Using annually resolved tree‐ring data...

Significance Two defining features of climate change in the Arctic are the rapid decline of sea ice and “shrubification” of the tundra. While previous studies have inferred warming-related linkages between the two, these have been limited to a few locations. Our Pan-Arctic analysis of shrub growth chronologies reveals two important insights. Tundra...

Geese can profoundly affect arctic ecosystems directly (e.g., by grazing vegetation) and indirectly (e.g. by changing nutrient cycling resulting from faces inputs and by reducing plant litter). In the Arctic, behavior and abundance of geese have changed due to climate and land-use change. While the short-term effects of increased goose populations...

Berry shrubs are found across the circumpolar North where they are an important source of food for people and animals. However, the environmental controls on berry productivity in these regions is poorly understood. This study presents the results of an ongoing berry productivity monitoring program for Empetrum nigrum L., Vaccinium uliginosum L., a...

The majority of variation in six traits critical to the growth, survival and reproduction of plant species is thought to be organised along just two dimensions, corresponding to strategies of plant size and resource acquisition. However, it is unknown whether global plant trait relationships extend to climatic extremes, and if these interspecific r...

Background: The functioning of ecosystems is highly variable through space and time. Climatic and edaphic factors are forcing ecological communities to converge, whereas the diversity of plant assemblages dampens these effects by allowing communities’ dynamics to diverge. This study evaluated whether the growing season phenology of wetland plant co...

Background: The functioning of ecosystems is highly variable through space and time. Climatic and edaphic factors are forcing ecological communities to converge, whereas the diversity of plant assemblages dampens these effects by allowing communities’ dynamics to diverge. This study evaluated whether the growing season phenology of plant communitie...

Invertebrate herbivores depend on external temperature for growth and metabolism. Continued warming in tundra ecosystems is proposed to result in increased invertebrate herbivory. However, empirical data about how current levels of invertebrate herbivory vary across the Arctic is limited and generally restricted to a single host plant or a small gr...

Background Scientific context • Rapidly increasing temperatures in the Arctic and decreasing snow cover duration have led to longer growing seasons affecting vegetation dynamics (treeline, shrubs advancing, ...). • Arctic greening trends are well documented (Fraser et al., 2011; Tremblay et al., 2012) and this knowledge is essential for understandi...

In the version of this Article originally published, the following sentence was missing from the Acknowledgements: “This work was supported by the Norwegian Research Council SnoEco project, grant number 230970”. This text has now been added.

Aim Plant functional groups are widely used in community ecology and earth system modelling to describe trait variation within and across plant communities. However, this approach rests on the assumption that functional groups explain a large proportion of trait variation among species. We test whether four commonly used plant functional groups rep...

Traditional food is central to Inuit culture and sense of identity. Recent changes in lifestyle, climate, and animal populations have influenced how people practice and experience activities on the land. We summarize the findings of 191 new and archived interviews addressing the continued relationships of Inuit to berries in the Canadian territorie...

Advancing phenology is one of the most visible effects of climate change on plant communities, and has been especially pronounced in temperature-limited tundra ecosystems. However, phenological responses have been shown to differ greatly between species, with some species shifting phenology more than others. We analysed a database of 42,689 tundra...

Motivation: The Tundra Trait Team (TTT) database includes field‐based measurements of key traits related to plant form and function at multiple sites across the tundra biome. This dataset can be used to address theoretical questions about plant strategy and trade‐offs, trait–environment relationships and environmental filtering, and trait variation...

Adjusting to global climate and socio-environmental changes has become a major issue for many societies, especially in the Arctic. Many Inuit wish to better understand the changes taking place. In 2013, an international Observatory of Human–Environment Interactions (OHMi) was established in Nunavik to identify these changes, study their cumulative...

The tundra is warming more rapidly than any other biome on Earth, and the potential ramifications are far-reaching because of global feedback effects between vegetation and climate. A better understanding of how environmental factors shape plant structure and function is crucial for predicting the consequences of environmental change for ecosystem...

Permafrost thaw, tundra shrubification, and changes in snow cover properties are documented impacts of climate warming, particularly in subarctic regions where discontinuous permafrost is disappearing. To obtain some insight into those changes, permafrost, active layer thickness, vegetation, snow cover, ground temperature, soil profiles, and carbon...

There is increasing interest in community-based environmental monitoring (CBEM) in Canada’s North in response to the rising impacts of resource exploitation and climate change, and with increased recognition of indigenous knowledge. IMALIRIJIIT, meaning those who study water in Inuktitut, is a CBEM program involving science land camps, capacity-bui...

The above mentioned article was originally scheduled for publication in the special issue on Ecology of Tundra Arthropods with guest editors Toke T. Høye . Lauren E. Culler. Erroneously, the article was published in Polar Biology, Volume 40, Issue 11, November, 2017. The publisher sincerely apologizes to the guest editors and the authors for the in...

Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litt...

Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time se...

Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time se...

Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community led open-source database of biodiversity time se...

A circumpolar increase in shrub growth and cover has been underway in Arctic and subarctic ecosystems for the last few decades, but there is considerable spatial heterogeneity in this shrubification process. Although topography, hydrology and edaphic factors are known to influence shrubification patterns, a better understanding of the landscape-sca...

Through litter decomposition enormous amount of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litte...

Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to under-stand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litt...

Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time se...

Large amplitude fluctuations in animal populations are well documented but their causes often remain unclear. In cyclic populations, predation (top-down) and food availability (bottom-up) are the most common hypotheses invoked to explain these cycles. In lemming populations, lack of food is suspected to drive population movements and cycles in Scan...

Aims: An Arctic Vegetation Classification (AVC) is needed to address issues related to rapid Arctic-wide changes to climate, land-use, and biodiversity. Location: The 7.1 million km2 Arctic tundra biome. Approach and conclusions: The purpose, scope and conceptual framework for an Arctic Vegetation Archive (AVA) and Classification (AVC) were develop...

Chronic, low intensity herbivory by invertebrates, termed background herbivory, has been understudied in tundra, yet its impacts are likely to increase in a warmer Arctic. The magnitude of these changes is however hard to predict as we know little about the drivers of current levels of invertebrate herbivory in tundra. We assessed the intensity of...

Northern wetlands and their productive tundra vegetation are of prime importance for Arctic wildlife by providing high-quality forage and breeding habitats. However, many wetlands are becoming drier as a function of climate-induced permafrost degradation. This phenomenon is notably the case in cold, ice-rich permafrost regions such as Bylot Island,...

Increasing growth of erect shrubs species, like Salix richardsonii, have been well documented in Arctic tundra. This shrubification of the North causes profound changes in water, energy and nutrient feedbacks between the biosphere, geosphere and atmosphere (REF). However, few studies have yet to examine the impact of these changes on the carbon cyc...

Shrub densification has been widely reported across the circumpolar arctic and subarctic biomes in recent years. Long-term analyses based on dendrochronological techniques applied to shrubs have linked this phenomenon to climate change. However, the multi-stemmed structure of shrubs makes them difficult to sample and therefore leads to non-uniform...

Warmer temperatures are accelerating the phenology of organisms around the world. Temperature sensitivity of phenology might be greater in colder, higher-latitude sites than in warmer regions, in part because small changes in temperature constitute greater relative changes in thermal balance at colder sites. To test this hypothesis, we examined up...

The change of water phase around 0 °C has considerable impacts on wildlife ecology because liquid and solid water strongly differ in their insulating capability, mechanical resistance, and light reflectance. Freeze and melt events thus have strong ecological relevance, particularly in the Arctic where snow and ice are omnipresent and their conditio...

The expansion of shrub vegetation in Arctic and sub-Arctic environments observed in the past decades can have significant effects on northern ecosystems. There is a need for efficient tools to monitor those changes, not only in terms of the spatial coverage of shrubs, but also their vertical growth. The objective of the current paper is to evaluate...

Shrub expansion is increasingly observed in arctic and subarctic environments. The development of shrub structure may significantly impact the abiotic environment at the local scale. Our objective was to reconstruct the development of the vertical structure of Betula glandulosa Michx. and to evaluate its effects on winter and summer soil temperatur...

Arctic terrestrial ecosystems are heterogeneous because of the strong influences of microtopography, soil moisture and snow accumulation on vegetation distribution. The interaction between local biotic and abiotic factors and global climate patterns will influence species responses to climate change. Salix arctica (Arctic willow) is a structuring s...

Aim Understanding the forces shaping biodiversity patterns, particularly for groups of organisms with key functional roles, will help predict the responses of ecosystems to environmental changes. Our aim was to evaluate the relative role of different drivers in shaping the diversity patterns of vertebrate herbivores, a group of organisms exerting a...

Low-center polygonal terrains with gentle sloping surfaces and lowlands in the high Arctic have a potential to retain water in the lower central portion of ice-wedge polygons and are considered high-latitude wetlands. Such wetlands in the continuous permafrost regions have an important ecological role in an otherwise generally arid region. In the v...

Continuous permafrost zones with well-developed polygonal ice-wedge networks are particularly vulnerable to climate change. Thermo-mechanical erosion can initiate the development of gullies that lead to substantial drainage of adjacent wet habitats. How vegetation responds to this particular disturbance is currently unknown but has the potential to...

Aim The A rctic has experienced marked climatic differences between glacial and interglacial periods and is now subject to a rapidly warming climate. Knowledge of the effects of historical processes on current patterns of diversity may aid predictions of the responses of vegetation to future climate change. We aim to test whether plant species and...

Shrubs are increasing in dominance in response to climate warming in the tundra biome. Although the phenomenon has been reported in the Low Arctic, it remains poorly documented in the High Arctic. Our work focuses on the distribution of the erect shrub Salix richardsonii at the northern limit of its range in Qarlikturvik valley on Bylot Island, Nun...