Georges Kunstler

Georges Kunstler
French National Institute for Agriculture, Food, and Environment (INRAE) | INRAE · Department of Territories

About

88
Publications
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Introduction

Publications

Publications (88)
Preprint
Full-text available
Aim: Linking local population dynamics and species distributions is critical to predicting the impacts of climate change. While many studies focus on the mean fitness of populations, theory shows that species distributions can be shaped by demographic stochasticity or population resilience. Here we examine how mean fitness (measured by invasion rat...
Preprint
Ecological theory aims to understand how and why species differences allow competitors to coexist, but explanations remain inconsistent with data. Tightly constrained parameter tradeoffs needed for coexistence in models contrast with evidence that forests can support high diversity and be invaded repeatedly by species that lack specialized tradeoff...
Preprint
The role of intraspecific variability (IV) in shaping community dynamics has been intensively discussed over the past decade and modeling studies have played an important role in that respect. However, a major, but often implicit, assumption typically made by these studies, that IV can be represented by independent random draws around species-speci...
Article
Full-text available
Lack of tree fecundity data across climatic gradients precludes the analysis of how seed supply contributes to global variation in forest regeneration and biotic interactions responsible for biodiversity. A global synthesis of raw seedproduction data shows a 250‐fold increase in seed abundance from cold‐dry to warm‐wet climates, driven primarily by...
Article
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The relationships that control seed production in trees are fundamental to understanding the evolution of forest species and their capacity to recover from increasing losses to drought, fire, and harvest. A synthesis of fecundity data from 714 species worldwide allowed us to examine hypotheses that are central to quantifying reproduction, a foundat...
Article
Full-text available
Recent climate warming has fueled interest into climate-driven range shifts of tree species. A common approach to detect range shifts is to compare the divergent occurrences between juvenile and adult trees along environmental gradients using static data. Divergent occurrences between life stages can, however, also be caused by onto-genetic effects...
Article
Full-text available
Significance Suitable habitats for forest trees may be shifting fast with recent climate change. Studies tracking the shift in suitable habitat for forests have been inconclusive, in part because responses in tree fecundity and seedling establishment can diverge. Analysis of both components at a continental scale reveals a poleward migration of nor...
Article
Aim The population processes that drive tree species distribution are still widely debated. We test the hypotheses that metapopulation processes of colonization and extinction are linked to predictions of species distribution models. Location Europe: Spain, France, Germany, Finland and Sweden. Taxon Angiosperms and Gymnosperms. Methods For 17 tr...
Article
Despite its importance for forest regeneration, food webs, and human economies, changes in tree fecundity with tree size and age remain largely unknown. The allometric increase with tree diameter assumed in ecological models would substantially overestimate seed contributions from large trees if fecundity eventually declines with size. Current esti...
Article
Full-text available
There is an urgent need to synthesize the state of our knowledge on plant responses to climate. The availability of open-access data provide opportunities to examine quantitative generalizations regarding which biomes and species are most responsive to climate drivers. Here, we synthesize time series of structured population models from 162 populat...
Article
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A Correction to this paper has been published: https://doi.org/10.1038/s41467-021-22025-2
Article
Full-text available
Indirect climate effects on tree fecundity that come through variation in size and growth (climate-condition interactions) are not currently part of models used to predict future forests. Trends in species abundances predicted from meta-analyses and species distribution models will be misleading if they depend on the conditions of individuals. Here...
Article
Full-text available
1. Species range limits are thought to result from a decline in demographic performance at range edges. However, recent studies reporting contradictory patterns in species demographic performance at their edges cast doubt on our ability to predict climate change demographic impacts. To understand these inconsistent demographic responses, we need to...
Preprint
Full-text available
To mitigate and adapt to climate change, there is an urgent need to synthesize the state of our knowledge on plant responses to climate. The availability of open-access data, combined with our understanding of plant physiology and life history theory provide opportunities to examine quantitative generalizations regarding which biomes and species ar...
Preprint
Full-text available
Species range limits are thought to result from a decline in demographic performance at range edges. However, recent studies reporting contradictory patterns in species demographic performance at their edges cast doubt on our ability to predict climate change demographic impacts. To understand these inconsistent demographic responses at the edges,...
Article
1.Over the coming decades, the predicted increase in frequency and intensity of extreme events such as droughts is likely to have a strong effect on forest functioning. Recent studies have shown that species mixing may buffer the temporal variability of productivity. However, most studies have focused on temporal stability of productivity, while sp...
Article
Full-text available
For decades, ecologists have investigated the effects of tree species diversity on tree productivity at different scales and with different approaches ranging from observational to experimental study designs. Using data from five European national forest inventories (16,773 plots), six tree species diversity experiments (584 plots), and six network...
Preprint
Full-text available
Aim Processes driving current tree species distribution are still largely debated. Attempts to relate species distribution and population demography metrics have shown mixed results. In this context, we would like to test the hypotheses that the metapopulation processes of colonization and extinction are linked to species distribution models. Loca...
Article
Size inequality has been considered a key feature of plant population structure with impacts on ecosystem functions. In forest ecosystems, studies examining the relationship between tree size inequality and stand productivity have produced mixed outcomes. These studies found positive, neutral or negative relationships and discussed how this could b...
Article
Key message In tree communities, tree size inequality reduces productivity and interacts with tree shade tolerance to modulate stand productivity, with a higher productivity in stands where shade-intolerant species dominate shade-tolerant species in size. Context Positive diversity–productivity relationships have been reported in different plant c...
Article
Key message A better transfer to managers of studies examining the functional role of tree species diversity would be achieved by explicitly addressing two missing links: the effect of management interventions on coexistence mechanisms and the relationships between coexistence mechanisms and ecosystem functions. Context Plant species diversity has...
Article
Full-text available
Humans require multiple services from ecosystems, but it is largely unknown whether trade-offs between ecosystem functions prevent the realisation of high ecosystem multifunctionality across spatial scales. Here, we combined a comprehensive dataset (28 ecosystem functions measured on 209 forest plots) with a forest inventory dataset (105,316 plots)...
Article
Full-text available
Damage due to wind storms and droughts are increasing in many temperate forest, yet little is known about the long-term roles of these key climatic factors in forest dynamics and in the carbon budget. The objective of this study was to estimate individual and coupled effects of droughts and wind-storms on adult tree mortality across a 31-year perio...
Article
We present repeated tree measurement data from 63 permanent plots in mountain forests in France. Plot elevations range from 800 (lower limit of the montane belt) to 1942 m a.s.l (subalpine belt). Forests mainly consist of pure or mixed stands dominated by European beech (Fagus sylvatica), Silver fir (Abies alba) and Norway spruce (Picea abies), in...
Book
Full-text available
Ce livret vient en complément du premier livret sur les idées reçues sur les risques naturels en montagne, paru en 2013. Il aborde la question des idées reçues sur le changement climatique en montagne, sur la base de connaissances acquises dans les projets de recherche du centre Irstea de Grenoble. Les risques en montagne vont-ils augmenter ou au c...
Article
Alexander et al. [1] made two really important points about species range boundaries. First, we still know very little about which boundaries are set by competition rather than by direct effects of temperature or other environmental variables. Second, reliable knowledge about this can come only from field experiments, transplanting species beyond t...
Article
Full-text available
Plant structural diversity is usually considered as beneficial for ecosystem functioning. For instance, numerous studies have reported positive species diversity-productivity relationships in plant communities. However, other aspects of structural diversity such as individual size inequality have been far less investigated. In forests, tree size in...
Data
Description of the French National Geographic Agency data and climatic data. (PDF)
Data
P-values from the models for the ten species. (PDF)
Data
Comparison of different analysis methods: lm vs. nls. (PDF)
Article
Ecologists have limited understanding of how geographic variation in forest biomass arises from differences in growth and mortality at continental to global scales. Using forest inventories from across North America, we partitioned continental-scale variation in biomass growth and mortality rates of 49 tree species groups into (1) species-independe...
Article
Full-text available
Phenotypic traits and their associated trade-offs have been shown to have globally consistent effects on individual plant physiological functions, but how these effects scale up to influence competition, a key driver of community assembly in terrestrial vegetation, has remained unclear. Here we use growth data from more than 3 million trees in over...
Article
Full-text available
Investigating how interactions among plants depend on environmental conditions is key to understand and predict plant communities’ response to climate change. However, while many studies have shown how direct interactions change along climatic gradients, indirect interactions have received far less attention. In this study, we aim at contributing t...
Article
Full-text available
Understanding the long-term impacts of invasive mammalian browsers and granivores in mixed forests is difficult due to the many processes potentially affecting the demography of long-lived trees. We constructed individual-based spatially explicit simulation models of two mixed conifer–angiosperm forests, growing on soils of contrasting phosphorus (P...
Article
Full-text available
Interestingly, relationships between demographic parameters and occurrence probability did not vary substantially across degrees of shade tolerance and regions. Although they were influenced by the uncertainty in the estimation of the demographic parameters, we found that r was generally negatively correlated with P-occ, while N, and for most regio...
Conference Paper
Full-text available
Uneven-aged forests are usually characterized by high size inequality of trees within stands. This dimension of heterogeneity has often been left out of the diversity-productivity debate which has mainly focused on species diversity. Our study aimed to bring quantitative answers to what effects size inequality has on the basal area production of pu...
Article
Full-text available
Climate change is expected to increase the magnitude and the frequency of extreme climatic events such as droughts. Better understanding how plant communities will respond to these droughts is a major challenge. We expect the response to be a shift in functional trait values resulting from both species turnover and intraspecific trait variability,...
Article
Full-text available
1.The importance of competition has been defined as the impact or role of competition relative to the total impact of the environment, and the intensity of competition is its absolute impact. Understanding the distinction has been proposed as key in reconciling long-running ecological debates. 2.An index of competition importance, Cimp, has been u...
Chapter
Full-text available
Climate scenarios suggest that current forest stands will face radically different temperature and precipitation conditions in the future. Developing future strategies for forest management in the face of uncertain and highly variable forecasts of future site conditions is a great challenge. Here we have analyzed transnational case studies dealing...
Article
1. Global warming is predicted to dramatically alter communities' composition through differ-ential colonization abilities, such as between sessile plants and their mobile herbivores. Novel interactions between previously non-overlapping species may, however, also be mediated by altered plants' responses to herbivore attack. 2. Syndromes of plant d...
Article
Full-text available
Context There is strong interest in sustainable forest management systems that preserve characteristics of forests close to naturalness. Assessing the effectiveness of these systems is difficult because defining “natural” baselines from which impacts are estimated is challenging and because the influence of harvesting can have complex interactions...
Article
Full-text available
Predicting climate-driven changes in plant distribution is crucial for biodiversity conservation and management under recent climate change. Climate warming is expected to induce movement of species upslope and towards higher latitudes. However, the mechanisms and physiological processes behind the altitudinal and latitudinal distribution range of...
Article
Full-text available
Tree mortality is a complex process that exhibits great spatio-temporal variability. Long term mortality data is needed to understand this demographic parameter and how it is related to biotic, climatic, and anthropogenic disturbances. Here, we propose a Bayesian state-space model to estimate tree mortality time series in managed forests, where tre...
Article
Full-text available
Despite empirical support for an increase in ecosystem productivity with species diversity in synthetic systems, there is ample evidence that this relationship is dependent on environmental characteristics, especially in structurally more complex natural systems. Empirical support for this relationship in forests is urgently needed, as these ecosys...
Data
Main characteristics of the forest inventories. (DOC)
Data
Results of the structural equation model (SEM). (DOC)
Data
Summary of multigroup comparison among forest types for single path coefficients. (DOC)
Data
Goodness-of-fit statistics for multigroup analyses. (DOC)
Article
1 Climate change is expected to increase the magnitude and the frequency of extreme climatic events such as droughts. Better understanding how plant communities will respond to these droughts is a major challenge. We expect the response to be a shift in functional trait values resulting from both species turnover and intraspecific trait variability...
Book
Ce chapitre d'ouvrage est une synthèse des résultats du projet SECALP à destination des gestionnaires et décideurs publics. L’objectif du projet SECALP était d’analyser les mécanismes d’adaptation des territoires semi-naturels de montagne face aux changements climatiques, particulièrement la récurrence des sécheresses. Les objectifs spécifiques éta...
Article
Full-text available
The relative importance of competition vs. environmental filtering in the assembly of communities is commonly inferred from their functional and phylogenetic structure, on the grounds that similar species compete most strongly for resources and are therefore less likely to coexist locally. This approach ignores the possibility that competitive effe...
Article
Full-text available
Mountain forests produce a large number of ecosystem services that are going to be affected by climate change. We are expecting an increase in high altitude species that could result in the decrease in resinous and subalpine species. These changes in species could adversely affect biodiversity and timber production. However, we also observe an incr...
Article
Full-text available
Encroachment of trees into low-productivity grasslands is a serious threat to grassland biodiversity throughout Europe. Although the rate of encroachment of trees into grassland is variable and poorly understood, it is thought to result from variation in tree seedling recruitment, which is limited mainly by the availability of safe sites and the di...
Article
Full-text available
Theoretical models predict weakening of negative biotic interactions and strengthening of positive interactions with increasing abiotic stress. However, most empirical tests have been restricted to plant-plant interactions. No empirical study has examined theoretical predictions of interactions between plants and below-ground micro-organisms, altho...
Article
Full-text available
1. Plant interactions play a central role in regulating plant communities and this role can be altered by abiotic stress. With increasing stress, ecological theory predicts that the role of competition decreases whilst that of facilitation increases. Such predictions have been tested with short-term plant removal experiments using two distinct indi...
Book
Dans ce livre, le Cemagref, institut de recherche en sciences et technologies pour l'environnement, fait le point de ses travaux scientifiques menés sur la forêt. Pourquoi une recherche sur la forêt ? D'abord parce qu'elle occupe plus d'un quart de la surface de notre territoire métropolitain. Ensuite, parce qu'elle fournit tout un ensemble de serv...
Article
Full-text available
Question Tree mortality can be modeled using two complementary covariates, tree size and tree growth. Tree growth is an integrative measure of tree vitality while tree diameter is a good index of sensitivity to disturbances and can be considered as a proxy for tree age which may indicate senescence. Few mortality models integrate both covariates be...
Article
Mountain forests produce a large number of ecosystem services that are going to be affected by climate change. We are expecting an increase in high altitude species that could result in the decrease in resinous and subalpine species. These changes in species could adversely affect biodiversity and timber production. However, we also observe an incr...
Article
Full-text available
Intra-specific variability often produces an overlap between species distributions of individual performances which can influence competition relations and community dynamics. We analysed a two-species competition–colonisation model of vegetation with intra-specific variability in juvenile growth. On each patch colonised by both species, the winner...
Article
Full-text available
Tree species differences in crown size and shape are often highlighted as key characteristics determining light interception strategies and successional dynamics. The phenotypic plasticity of species in response to light and space availability suggests that intraspecific variability can have potential consequences on light interception and communit...
Article
Full-text available
1. Due to species-specificity of the outcomes of biotic interactions, it is difficult to generalize from observed biotic interactions at the individual plant level to the effect of those interactions at the community level. To evaluate the importance of biotic interactions in shaping plant communities, it is necessary to understand how the outcomes...
Conference Paper
Background/Question/Methods The response of individuals to their environment is determined by a set of life traits, which are usually assumed as characteristic of species in modelling and experimental studies. Genetic variability, local micro-variations and historical contingency lead nevertheless to variations of traits among individuals of a sam...