Sonia Kéfi

Sonia Kéfi
French National Centre for Scientific Research | CNRS · Institut des Sciences de l'Evolution de Montpellier

Ph.D.

About

160
Publications
59,867
Reads
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6,796
Citations
Additional affiliations
January 2011 - present
Université de Montpellier
Position
  • Researcher
January 2011 - present
French National Centre for Scientific Research
Position
  • Researcher
February 2009 - December 2010
Georg-August-Universität Göttingen
Position
  • PostDoc Position

Publications

Publications (160)
Article
Anthropogenic activities are increasingly affecting ecosystems across the globe. Meanwhile, empirical and theoretical evidence suggest that natural systems can exhibit abrupt collapses in response to incremental increases in the stressors, sometimes with dramatic ecological and economic consequences. These catastrophic shifts are faster and larger...
Article
Human activities put ecosystems under increasing pressure, often resulting in local extinctions. However, it is unclear how local extinctions affect regional processes, such as the distribution of diversity in space, especially if extinctions show spatial patterns, such as being clustered. Therefore, it is crucial to investigate extinctions and the...
Article
Full-text available
Recurrent fires can impede the spontaneous recruitment capacity of pine forests. Empirical studies have suggested that this can lead to a prolonged replacement of pine forest by shrubland, especially if shrub species are pyrophytic. Model-based studies, however, have suggested that post-fire succession of pine forest under current climatic conditio...
Article
Full-text available
Many factors are known to influence the invasion of alien species depending on the spatial scales considered. Caulerpa taxifolia and Caulerpa cylindracea are two green macroalgae that are classified as among the most invasive exotic macroalgae in the world. Their spread into the Mediterranean Sea seems to be favored by the concomitant decline of Po...
Article
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The impact of global change on biodiversity is commonly assessed in terms of changes in species distributions, community richness and community composition. Whether and how much associations between species are also changing is much less documented. In this study, we quantify changes in large-scale patterns of species associations in bird communiti...
Preprint
Full-text available
Even when environments deteriorate gradually, ecosystems may shift abruptly from one state to another. Such catastrophic shifts are difficult to predict and reverse (hysteresis). While well studied in simplified contexts, we lack a general understanding of how catastrophic shifts spread in realistic spatial contexts. For different types of landscap...
Preprint
Full-text available
Complex networks have become the main paradigm for modelling the dynamics of interacting systems. However, networks are intrinsically limited to describing pairwise interactions, whereas real-world systems are often characterized by higher-order interactions involving groups of three or more units. Higher-order structures, such as hypergraphs and s...
Preprint
Full-text available
Until recently, most ecological network analyses have focused on a single interaction type. In nature, however, diverse interactions co-occur, each of them forming a layer of a ‘multilayer’ network. Data including information on multiple interactions has recently started to emerge, giving us the opportunity to have a first glance at possible common...
Article
Full-text available
Complex networks have become the main paradigm for modelling the dynamics of interacting systems. However, networks are intrinsically limited to describing pairwise interactions, whereas real-world systems are often characterized by higher-order interactions involving groups of three or more units. Higher-order structures, such as hypergraphs and s...
Article
Full-text available
Dryland ecosystems are likely to respond discontinuously to gradual changes in environmental conditions. Direct facilitation between plants, whereby plants improve the local environmental conditions for others, has been shown to be a mechanism contributing to these discontinuous ecosystem transitions. Theoretical models describing dryland vegetatio...
Article
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The original version of this article unfortunately contained a mistake. The 2nd affiliation of Sonia Kéfi was missing
Article
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Despite their extent and socio‐ecological importance, a comprehensive biogeographical synthesis of drylands is lacking. Here we synthesize the biogeography of key organisms (vascular and non‐vascular vegetation and soil microorganisms), attributes (functional traits, spatial patterns, plant‐plant and plant‐soil interactions) and processes (producti...
Article
The biodiversity and ecosystem functioning (BEF) relationship is expected to be scale-dependent. The autocorrelation of environmental heterogeneity is hypothesized to explain this scale dependence because it influences how quickly biodiversity accumulates over space or time. However, this link has yet to be demonstrated in a formal model. Here, we...
Preprint
Full-text available
Mutualistic networks have attracted increasing attention in the ecological literature in the last decades as they play a key role in the maintenance of biodiversity. Here, we develop an analytical framework to study the structural stability of these networks including both mutualistic and competitive interactions. Analytical and numerical analyses...
Article
Interactions are key drivers of the functioning and fate of plant communities. A traditional way to measure them is to use pairwise experiments, but such experiments do not scale up to species‐rich communities. For those, using association networks based on spatial patterns may provide a more realistic approach. While this method has been successfu...
Preprint
Full-text available
The biodiversity and ecosystem functioning (BEF) relationship is expected to be scale-dependent. The autocorrelation of environmental heterogeneity is hypothesized to explain this scale dependence because it influences how quickly biodiversity accumulates over space or time. However, this link has yet to be demonstrated in a formal model. Here we u...
Preprint
Full-text available
Human activities lead more and more to the disturbance of plant and animal communities with local extinctions as a consequence. While these negative effects are clearly visible at a local scale, it is less clear how such local patch extinctions affect regional processes, such as metacommunity dynamics and the distribution of diversity in space. Sin...
Preprint
Full-text available
Aim The impact of global change on biodiversity is commonly assessed in terms of changes in species distributions, species richness and species composition across communities. Whether and how much interactions between species are also changing is much less documented and mostly limited to local studies of ecological networks. Moreover, we largely i...
Article
Full-text available
One of the most challenging issues in Mediterranean ecosystems to date has been to understand the emergence of discontinuous changes or catastrophic shifts. In the era of the 2030 Sustainable Development Goals, which encompass ideas around Land Degradation Neutrality, advancing this understanding has become even more critical and urgent. The aim of...
Article
Understanding the drivers of geographical variation of species distributions, and of the resulting community structure, constitutes one of the grandest challenges in ecology. Geographical patterns of species richness and composition have been relatively well studied. Less is known about how the entire set of trophic and non‐trophic ecological inter...
Article
The configuration of a habitat often reflects its conservation status and, to be effective, the conservation actions to be implemented must be adapted to local environmental conditions and human activities. Here, we take advantage of a fine resolution map (1:10000) of marine habitats to study the spatial configuration of Posidonia oceanica seagrass...
Chapter
Ecological systems are undeniably complex, including many species interacting in different ways with each other (e.g., predation, competition, facilitation, parasitism). One way of visualizing, describing, and studying this complexity is to represent them as networks, where nodes are typically species and links are interactions between these specie...
Chapter
Ecological systems are prone to dramatic shifts between alternative stable states. In reality, these shifts are often caused by slow forces external to the system that eventually push it over a tipping point. Theory predicts that when ecological systems are brought close to a tipping point, the dynamical feedback intrinsic to the system interact wi...
Article
Full-text available
A rich body of knowledge links biodiversity to ecosystem functioning (BEF), but it is primarily focused on small scales. We review the current theory and identify six expectations for scale dependence in the BEF relationship: (1) a nonlinear change in the slope of the BEF relationship with spatial scale; (2) a scale‐dependent relationship between e...
Article
Understanding the stability of ecological communities is a matter of increasing importance in the context of global environmental change. Yet it has proved to be a challenging task. Different metrics are used to assess the stability of ecological systems, and the choice of one metric over another may result in conflicting conclusions. Although each...
Article
Full-text available
Identified as essential mechanisms promoting alternative stable states, positive feedbacks have been the focus of most former studies on the potential for catastrophic shifts in drylands. Conversely, little is known about how negative feedbacks could counterbalance the effects of positive feedbacks. A decrease in vegetation cover increases the conn...
Article
Full-text available
The concept of ecological stability occupies a prominent place in both fundamental and applied ecological research. We review decades of work on the topic and examine how our understanding has progressed. We show that our understanding of stability has remained fragmented and is limited largely to simple or simplified systems. There has been a prof...
Article
Full-text available
Ecological communities are undeniably diverse, both in terms of the species that compose them as well as the type of interactions that link species to each other. Despite this long recognition of the coexistence of multiple interaction types in nature, little is known about the consequences of this diversity for community functioning. In the ongoin...
Article
Full-text available
1.Among plant traits, plant secondary metabolites such as tannins mediate plantherbivore interactions but also have after‐life effects on litter decomposition and nutrient cycling. We propose that niche construction mechanisms based on positive plant‐soil feedbacks (PSF) could influence the evolution of tannin production. 2. By modeling the flow of...
Chapter
The idea that ecosystems may have multiple alternative stable states dates back to the late 1960s–early 1970s, when ecologists realized that this type of behavior could arise in simple mathematical models. A direct consequence is that such ecosystems can suddenly switch (or “tip”) between their alternative stable states rather than gradually respon...
Article
Full-text available
Predator–prey interactions in natural ecosystems generate complex food webs that have a simple universal body-size architecture where predators are systematically larger than their prey. Food-web theory shows that the highest predator–prey body-mass ratios found in natural food webs may be especially important because they create weak interactions...
Article
Community Weighted Means (CWM) are valuable tools describing community composition with respect to one given trait. They have been widely used as indicators in global change studies to measure biodiversity responses to environmental perturbations. However, how individual species contribute to such community indicators has hardly been investigated....
Article
Full-text available
Facilitation occurs when one species positively impacts the fitness of another, and has predominantly been studied in free-living species like plants. Facilitation can also occur among symbiont (mutualistic or parasitic) species or strains, but equivalent studies are scarce. To advance an integrated view of the effect of facilitation on symbiont ec...
Article
Full-text available
1.A framework for the description and analysis of multilayer networks is established in statistical physics and calls are increasing for their adoption by community ecologists. Multilayer networks in community ecology will allow space, time, and multiple interaction types to be incorporated into species‐interaction networks. 2. While the multilayer...
Preprint
Full-text available
Ecological communities are undeniably diverse, both in terms of the species that compose them as well as the type of interactions that link species to each other. Despite this long-recognition of the coexistence of multiple interaction types in nature, little is known about the consequences of this diversity for community functioning. In the ongoin...
Article
Full-text available
The spatial configuration of vascular vegetation has been linked to variations in land degradation and ecosystem functioning in drylands. However, most studies on spatial patterns conducted to date have focused on a single or a few study sites within a particular region, specific vegetation types, or in landscapes characterized by a certain type of...
Article
Full-text available
Question Positive interactions between plants have well‐known effects on community species richness and biomass via micro‐environment improvements. However, the effects of indirect facilitation performed by a nurse on an associated plant community, occurring for example through the protection against grazing, have not attracted much attention in th...
Article
Full-text available
1.Some ecosystems show non‐linear responses to gradual changes in environmental conditions, once a threshold in conditions ‐ or critical point ‐ is passed. This can lead to wide shifts in ecosystem states, possibly with dramatic ecological and economic consequences. Such behaviors have been reported in drylands, savannas, coral reefs or shallow lak...
Article
1.Disentangling the interplay between species‐specific environmental preferences and micro‐ and macro‐scale determinants of species abundance within plant communities remains challenging. Most existing studies addressing this issue either lack empirical data regarding species interactions and local abundances or cover a narrow range of environmenta...
Preprint
Full-text available
Among plant traits, plant secondary metabolites such as tannins mediate plant-herbivore interactions but also have after-life effects on litter decomposition and nutrient cycling, which could influence their evolution. By modeling the flow of nitrogen and carbon through plants and soil in a spatially explicit context, we explored the relative contr...
Article
Full-text available
In the version of this Article originally published, the values of two of the functions used to calculate the multifunctionality index were incorrect, which affected Figs 3,4 of the main article and Supplementary Figs 3,4,5,6,9. Please see the correction notice for full details.
Article
Ecosystems that exhibit alternative stable states are a prominent challenge for ecological restoration. So far, alternative stable states have been addressed from two different angles: community assembly studies, which focus on species and their interactions, and regime shift studies, which focus on changes in ecosystem states following environment...
Book
Full-text available
Adaptive Food Webs is a synthesis of talks from the fourth decadal conference on food webs, after the publishing of the seminal book by Robert May entitled Stability and Complexity in Model Ecosystems. It embraces the notion of food webs as being complex adaptive systems by exploring dynamic structures and processes, through both changes in externa...
Article
Full-text available
Facilitation among plants mediated by grazers occurs when an unpalatable plant extends its protection against grazing to another plant. This type of indirect facilitation impacts species coexistence and ecosystem functioning in a large array of ecosystems worldwide. It has nonetheless generally been understudied so far in comparison with the role p...
Article
Theory suggests that ecological systems exhibit a pronounced slow down in their dynamics, known as 'critical slowing down' (CSD), before they undergo regime shifts or critical transitions. As a result of CSD, ecosystems exhibit characteristic temporal and spatial changes which can be used as early warning signals of imminent regime shifts. For temp...
Preprint
Full-text available
The size distribution of discrete plant patches (PSD), a common descriptor of the spatial patterns of vascular vegetation, has been linked to variations in land degradation and ecosystem functioning in drylands. However, most studies on PSDs conducted to date have focused on a single or a few study sites within a particular region. Therefore, littl...
Article
Full-text available
In the current context of global change and a biodiversity crisis, there are increasing demands for greater predictive power in ecology, in both the scientific literature and at the science–policy interface. The implicit assumption is that this will increase knowledge and, in turn lead to better decision-making. However, the justification for this...
Conference Paper
Full-text available
Drylands cover about 31% of the European landmass, and are the home of around 25% of its population, thereby making the lives of a substantial part of the European population directly or indirectly dependent on the wellbeing of these drylands. Research done by the European Environmental Agency (EEA), shows that especially the area around the Medite...
Method
Full-text available
The time needed for ecosystems to recover from a disturbance has been proposed as a generic indicator of ecosystem resilience. The lengthening of the recovery time with increasing stress is referred to as “Critical Slowing Down” and has been proposed as an early warning of a nearing tipping point. Hence, methodologies for measuring recovery rates a...
Data
Data bundle including code supporting the publication: van Belzen, J., van de Koppel,, J., Kirwan, M.L., van der Wal, D., Herman, P.M.J., Dakos, V., Kefi, S., Scheffer, M., Guntenspergen, G.R., Bouma, T.J. (2017). Vegetation recovery in tidal marshes reveals critical slowing down under increased inundation. Nature Communications 8, 15811 doi: 10.10...
Data
Supplementary Figures, Supplementary Tables, Supplementary Notes and Supplementary References