Mark Vellend

Mark Vellend
Université de Sherbrooke | UdeS · Department of Biology

About

169
Publications
92,817
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
18,806
Citations

Publications

Publications (169)
Preprint
Plant ecologists use functional traits to describe how plants respond to and influence their environment. Reflectance spectroscopy can provide rapid, non-destructive estimates of leaf traits, but it remains unclear whether general trait-spectra models can yield accurate estimates across functional groups and ecosystems. We measured leaf spectra and...
Article
Full-text available
Land‐use change is widely regarded as a simplifying and homogenising force in nature. In contrast, analysing global land‐use reconstructions from the 10th to 20th centuries, we found progressive increases in the number, evenness, and diversity of ecosystems (including human‐modified land‐use types) present across most of the Earth’s land surface. E...
Preprint
Full-text available
Many plant species are predicted to migrate poleward in response to climate change. Species distribution models (SDMs) have been widely used to quantify future suitable habitats and potential migration distances, but SDM studies typically neglect soil properties, despite their importance for plant fitness. In this study, we built three SDMs – one w...
Article
Full-text available
Ectomycorrhizas and arbuscular mycorrhizas, the two most widespread plant–fungal symbioses, are thought to differentially influence tree species diversity, with positive plant–soil feedbacks favouring locally abundant ectomycorrhizal tree species and negative feedbacks promoting species coexistence and diversity in arbuscular mycorrhizal forests. W...
Article
Full-text available
ContextAlteration of natural vegetation cover across the landscape drives biodiversity changes. Although several studies have explored the relationships between vegetation cover and species richness, as well as between land-cover variance and species richness, few have considered the non-independence of these two biodiversity drivers.Objectives The...
Preprint
Full-text available
Despite many studies showing biodiversity responses to warming, the generality of such responses across taxonomic groups remains unclear. Very few studies have tested for evidence of bryophyte community responses to warming, even though bryophytes are major contributors to diversity and functioning in many ecosystems. Here we report an empirical st...
Preprint
Full-text available
Despite many studies showing biodiversity responses to warming, the generality of such responses across taxonomic groups remains unclear. Very few studies have tested for evidence of bryophyte community responses to warming, even though bryophytes are major contributors to diversity and functioning in many ecosystems. Here we report an empirical st...
Preprint
Full-text available
Land-use change is widely regarded as a simplifying and homogenising force in nature. In contrast, analysing global land-use reconstructions from the 10th to 20th centuries, we found progressive increases in the number, evenness, and diversity of ecosystems (including human-modified land-use types) across the globe. Ecosystem diversity increased mo...
Article
Premise: One of the best-documented ecological responses to climate warming involves temporal shifts of phenological events. However, we lack an understanding of how phenological responses to climate change vary among populations of the same species. Such variability has the potential to affect flowering synchrony among populations and hence the p...
Preprint
The direction and magnitude of long-term changes in local plant species richness are highly variable among studies, while species turnover is ubiquitous. However, it is unknown whether the nature of species turnover is idiosyncratic or whether certain types of species are consistently gained or lost across different habitats. To address this questi...
Preprint
Full-text available
Ectomycorrhizas and arbuscular mycorrhizas, the two most widespread plant-fungal symbioses, are thought to differentially influence tree species diversity, with positive plant-soil feedbacks favoring locally abundant ectomycorrhizal tree species and negative feedbacks promoting species coexistence and diversity in arbuscular mycorrhizal forests. Wh...
Article
Full-text available
Differences between the distributions of tree saplings and adults in geographic or niche space have been used to infer climate change effects on tree range dynamics. Previous studies have reported narrower latitudinal or climatic niche ranges of juvenile trees compared to adults, concluding that tree ranges are contracting, contradicting climate‐ba...
Article
Despite global biodiversity losses, trends at local and regional scales are context dependent. Recent studies have been criticized for lacking baselines preceding human impacts, and few such studies have addressed the landscape scale. Our aim was to quantify temporal trends in landscape‐scale tree diversity during an unambiguous period of massively...
Article
Full-text available
1. A better understanding of how disturbance impacts tree diversity at different scales is essential for our ability to conserve and manage forest ecosystems in the context of global changes. Here we test the impacts of land‐use related disturbances on tree diversity since the 19th century across a broad region (>150,000 km2) of northern temperate...
Article
Models of ecological responses to climate warming predict species’ migration towards higher latitudes or elevations. However, models often neglect non-climatic factors, such as herbivory, that could slow down or prevent geographic range expansion. A previous study in Mont Mégantic National Park (Québec) found that in one year (2016) white-tailed de...
Article
Full-text available
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...
Article
Full-text available
Abstract Climate change and other anthropogenic drivers of biodiversity change are unequally distributed across the world. Overlap in the distributions of different drivers have important implications for biodiversity change attribution and the potential for interactive effects. However, the spatial relationships among different drivers and whether...
Article
Climate warming is expected to cause the poleward and upward elevational expansion of temperate plant species, but non‐climatic factors such as soils could constrain this range expansion. However, the extent to which edaphic constraints on range expansion have an abiotic (e.g. soil chemistry) or biotic (e.g. micro‐organisms) origin remains undeterm...
Article
Human activities are fundamentally altering biodiversity. Projections of declines at the global scale are contrasted by highly variable trends at local scales, suggesting that biodiversity change may be spatially structured. Here, we examined spatial variation in species richness and composition change using more than 50,000 biodiversity time serie...
Article
Evolutionary biologists have long trained their sights on adaptation, focusing on the power of natural selection to produce relative fitness advantages while often ignoring changes in absolute fitness. Ecologists generally have taken a different tack, focusing on changes in abundance and ranges that reflect absolute fitness while often ignoring rel...
Article
Full-text available
Macroclimate warming is often assumed to occur within forests despite the potential for tree cover to modify microclimates. Here, using paired measurements, we compared the temperatures under the canopy versus in the open at 98 sites across 5 continents. We show that forests function as a thermal insulator, cooling the understory when ambient tempe...
Article
Although evidence suggests that humans have elevated global extinction rates and lowered global species richness, species richness at scales smaller than the globe can increase, decrease or remain the same. However, the role of spatial scale is rarely considered as a modifier in driving how richness change unfolds. We first observed richness change...
Article
Full-text available
Predicting future ecosystem dynamics depends critically on an improved understanding of how disturbances and climate change have driven long-term ecological changes in the past. Here we assembled a dataset of >100,000 tree species lists from the 19th century across a broad region (>130,000km²) in temperate eastern Canada, as well as recent forest i...
Article
Full-text available
The National Ecological Observatory Network (NEON) is designed to facilitate an understanding of the impact of environmental change on ecological systems. Observations of plant diversity—responsive to changes in climate, disturbance, and land use, and ecologically linked to soil, biogeochemistry, and organisms—result in NEON data products that cros...
Article
Full-text available
Many studies of individual sites have revealed biotic changes consistent with climate warming (e.g., upward elevational distribution shifts), but our understanding of the tremendous variation among studies in the magnitude of such biotic changes is minimal. In this study we re‐surveyed forest vegetation plots 40 years after the initial surveys in t...
Article
Over the past two decades, natural history collections (NHCs) have played an increasingly prominent role in global change research, but they have still greater potential, especially for the most diverse group of animals on Earth: insects. Here, we review the role of NHCs in advancing our understanding of the ecological and evolutionary responses of...
Preprint
Full-text available
Human activities have fundamentally altered biodiversity. Extinction rates are elevated and model projections suggest drastic biodiversity declines. Yet, observed temporal trends in recent decades are highly variable, despite consistent change in species composition. Here, we uncover clear spatial patterns within this variation. We estimated trends...
Article
Full-text available
Ecological communities change in time and space, but long-term dynamics at the century-to-millennia scale are poorly documented due to lack of relevant data sets. Nevertheless, understanding long-term dynamics is important for explaining present-day biodiversity patterns and placing conservation goals in a historical context. Here, we use recent ex...
Preprint
Full-text available
Climate change and other anthropogenic drivers of biodiversity change are unequally distributed across the world. The geographic patterns of different drivers, and the spatial overlap among these drivers, have important implications for the direction and pace of biodiversity change, yet are not well documented. Moreover, it is unknown if the geogra...
Article
Full-text available
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...
Article
Full-text available
Aims Both ecological drift and environmental heterogeneity can produce high beta diversity among communities, but only the effect of drift is expected to be enhanced in communities of small size. Few studies have explicitly tested the influence of community size on patterns of beta diversity. Here we applied a series of analyses aimed at testing th...
Preprint
Full-text available
Many studies of individual sites have revealed biotic changes consistent with climate warming (e.g., upward elevational distribution shifts), but our understanding of the tremendous variation among studies in the magnitude of such biotic changes is minimal. In this study we re-surveyed forest vegetation plots 40 years after the initial surveys in t...
Article
The contemporary state of functional traits and species richness in plant communities depends on legacy effects of past disturbances. Whether temporal responses of community properties to current environmental changes are altered by such legacies is, however, unknown. We expect global environmental changes to interact with land-use legacies given d...
Article
Full-text available
The match between functional trait variation in communities and environmental gradients is maintained by three processes: phenotypic plasticity and genetic differentiation (intraspecific processes), and species turnover (interspecific). Recently, evidence has emerged suggesting that intraspecific variation might have a potentially large role in dri...
Article
Full-text available
Plant communities have undergone dramatic changes in recent centuries, although not all such changes fit with the dominant biodiversity-crisis narrative used to describe them. At the global scale, future declines in plant species diversity are highly likely given habitat conversion in the tropics, although few extinctions have been documented for t...
Article
Full-text available
It is generally accepted that human activities are responsible for the dispersal of exotic earthworms in northeastern North America. We know little, however, about the relative effects of concurrent human activities on the structure of these earthworm communities in protected forest areas, nor on their impacts on soil biological activities. Our fir...
Data
Data S1. Appendix S1. PRISMA diagram Appendix S2. References of studies included in meta‐analysis Appendix S3. Metadata of ‘Cravenetal_Earthworms_PlantDiversity.csv’ Appendix S4. Metadata of ‘Cravenetal_EffectSizes_Earthworms_PlantFunctGroups.csv’ Table S1. Studies included in meta‐analysis and additional information about each study Table S2...
Data
Data S3. Cravenetal_Earthworms_PlantFunctionalGroups.csv Data file containing effect sizes of relationships between introduced earthworm communities and cover of plant functional groups of forest understory communities in North America.
Data
Data S2. Cravenetal_Earthworms_PlantDiversity.csv Data file containing effect sizes of relationships between introduced earthworm communities and plant species diversity, evennness, and richness of forest understory communities in North America.
Article
Full-text available
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...
Article
Full-text available
More and more ecologists have started to resurvey communities sampled in earlier decades to determine long-term shifts in community composition and infer the likely drivers of the ecological changes observed. However, to assess the relative importance of and interactions among multiple drivers, joint analyses of resurvey data from many regions span...
Article
The enemy release hypothesis is frequently invoked to explain invasion by non-native species, but studies focusing on the influence of enemies on natural plant range expansion due to climate change remain scarce. We combined multiple approaches to study the influence of plant-enemy interactions on the upper elevational range limit of sugar maple (A...
Article
We present new data and analyses revealing fundamental flaws in a critique of two recent meta-analyses of local-scale temporal biodiversity change. First, the conclusion that short-term time series lead to biased estimates of long-term change was based on two errors in the simulations used to support it. Second, the conclusion of negative relations...
Article
Full-text available
Globally, biological invasions can have strong impacts on biodiversity as well as ecosystem functioning. While less conspicuous than introduced aboveground organisms, introduced belowground organisms may have similarly strong effects. Here, we synthesize for the first time the impacts of introduced earthworms on plant diversity and community compos...
Article
Full-text available
In the absence of migration, species persistence depends on adaption to a changing environment, but whether and how adaptation to global change is altered by community diversity is not understood. Community diversity may prevent, enhance or alter how species adapt to changing conditions by influencing population sizes, genetic diversity and/or the...
Data
Supplementary Figures 1-4, Supplementary Tables 1-9, Supplementary Notes 1-2, Supplementary Methods and Supplementary References
Article
Rapidly rising temperatures are expected to cause latitudinal and elevational range shifts as species track their optimal climate north and upward. However, a lack of adaptation to environmental conditions other than climate - for example photoperiod, biotic interactions, or edaphic conditions - might limit the success of immigrants in a new locati...
Preprint
Full-text available
Two recent meta-analyses of local-scale biodiversity change over time, by the authors of the present paper, have been subject to a harsh critique. Here we use new data and analyses to respond to the main points of this critique. First, a central argument of the critique was that short-term time series lead to biased estimates of long-term biodivers...
Article
Recent changes in climate have led to significant shifts in phenology, with many studies demonstrating advanced phenology in response to warming temperatures. The rate of temperature change is especially high in the Arctic, but this is also where we have relatively little data on phenological changes and the processes driving these changes. In orde...
Article
Rapid climate warming in the tundra biome has been linked to increasing shrub dominance. Shrub expansion can modify climate by altering surface albedo, energy and water balance, and permafrost yet the drivers of shrub growth remain poorly understood. Dendroecological data consisting of multi-decadal time series of annual shrub growth provide an und...
Article
Intraspecific trait variation (ITV) plays a potentially important role in determining functional community composition across environmental gradients. However, the importance of ITV varies greatly among studies, and we lack a coherent understanding of the contexts under which to expect a high vs. low contribution of ITV to trait-environment matchin...
Article
Variation among species in their phenological responses to temperature change suggests that shifts in the relative timing of key life cycle events between interacting species are likely to occur under climate warming. However, it remains difficult to predict the prevalence and magnitude of these shifts given that there have been few comparisons of...
Article
Full-text available
An understanding of the historical range of variability of an ecosystem can improve management and restoration activities, but this variability depends on the spatial and temporal scale at which it is measured. We examined the extent of local-scale variation in vegetation prior to European settlement across a savannah-forest landscape mosaic on sou...
Article
Full-text available
Theory suggests that species with different traits will respond differently to landscape fragmentation. Studies have shown that the presence of species in fragments of varying size, shape and connectivity is dependent on plant traits related to dispersal ability, persistence and disturbance tolerance. However, the role of traits in determining long...
Article
1.The phenology of many species is shifting in response to climatic changes and these shifts are occurring at varying rates across species. This can potentially affect species' interactions and individual fitness. However, few studies have experimentally tested the influence of warming on the timing of species interactions. This is an important gap...
Article
Full-text available
We are limited in our ability to predict climate-change-induced range shifts by our inadequate understanding of how non-climatic factors contribute to determining range limits along putatively climatic gradients. Here, we present a unique combination of observations and experiments demonstrating that seed predation and soil properties strongly limi...
Article
1. Habitat patches that have been completely cleared of their original vegetation historically and subsequently recolonized naturally provide a useful study system to explore the importance of the processes involved in community assembly. Forests where the understorey vegetation is recovering from past agricultural land use form an iconic example o...
Article
Many species show evidence of climate-driven distribution shifts towards higher elevations, but given the tremendous variation among species and regions, we lack an understanding of the community-level consequences of such shifts. Here we test for signatures of climate warming impacts using a repeat survey of semi-permanent vegetation plots in 1970...
Article
A central current debate in community ecology concerns the relative importance of deterministic versus stochastic processes underlying community structure. However, the concept of stochasticity presents several profound philosophical, theoretical and empirical challenges, which we address here. The philosophical argument that nothing in nature is t...
Article
Full-text available
We recently assessed plant community responses to macroclimate warming across European and North American temperate forests (1). To do so, we inferred the temperature preferences of understory species from distribution data by means of ecological niche, or species distribution models (SDMs). Harwood et al. (2) propose that subcanopy temperatures, i...
Article
Biodiversity is comprised of genetic and phenotypic variation among individual organisms, which might belong to the same species or to different species. Spatial patterns of biodiversity are of central interest in ecology and evolution for several reasons: to identify general patterns in nature (e.g., species-area relationships, latitudinal gradien...