Olivier Chabrerie - Profile on Academia.edu (original) (raw)

Papers by Olivier Chabrerie

The use of domestic animal grazing to manage temperate salt-marsh ecosystems is still debated and... more The use of domestic animal grazing to manage temperate salt-marsh ecosystems is still debated and requires further field investigations. The effects of sheep grazing on plant community were studied in the salt-marshes of the Bay of Somme (France). We compared vegetation characteristics between two sets of grazed and ungrazed 1m2-plots. We tested for differences in species composition using pair-wise Multi-Response Permutation Procedures (MRPP), used an Indicator Species Analysis (ISA) to distinguish species indicator of grazed and ungrazed areas and described community structures with species rank-abundance curves. Differences in species richness and plant height and biovolume were tested using Mann-Whitney tests. MRPP showed that plant community composition differed significantly between grazed plots, dominated by Puccinellia maritima and Festuca rubra ssp. litoralis, and ungrazed plots, dominated by Halimione portulacoides (T = -60.37; A = 0.10; p < 0.0001). Nine species were i...

Thermal preference plasticity and fitness of an invasive polyphagous insect in heterogeneous environments

International audienceClimate change has a strong impact on insects, including changes in phenolo... more International audienceClimate change has a strong impact on insects, including changes in phenology, distribution area or population extinction. The capacity for behavioral thermoregulation then becomes a crucial trait when the environment is sufficiently heterogeneous to allow individuals to find areas that are always favorable to sub-lethal. Thermal preference (also called selected temperature) is a central trait in behavioral thermoregulation, but to date very few studies have analyzed in depth the plasticity of this trait and the mechanisms (adaptive or not) underlying this plasticity. The study proposed here consists of analyzing this trait in an invasive insect whose invasion success has been dazzling: Drosophila suzukii. This fly has spread widely in Europe, despite having rather low thermal resistance traits compared to other species. Our hypothesis is that the plasticity of the thermal preference allows this fly to constantly make the "right choices" by selecting favorable microclimates during all seasons. This polyphagous fly causes significant economic damage, and its ability to lay and develop in a wide range of fruits (cultivated and wild) must play a role in this success. The thesis consists in determining the interaction between temperature and the resource (identity of the fruit) in the success of Drosophila suzukii. Are there tradeoffs between host (resource) selection and behavioral thermoregulation? The experiments aim to quantify the plasticity of thermal preference as a function of environmental conditions (thermal and trophic). The thesis will identify the adaptive value (fitness) of the thermal preference plasticity in a context of climate change

POLLIFLOR : Caractérisation fonctionnelle des habitats agropastoraux pour les communautés d’insectes pollinisateurs

International audienc

Agronomy, 2019

Salinity is one of the most important stresses that reduces plant growth and productivity in seve... more Salinity is one of the most important stresses that reduces plant growth and productivity in several parts of the world. Nine Tunisian durum wheat genotypes grown under hydroponic conditions were subjected to two levels of salt stress (100 and 170 mM NaCl) for 21 days. An integrative analysis revealing the impact of salinity on key phenotypic and physiological marker traits was then conducted. Principal component analysis grouped these traits into three different clusters corresponding to the absence of salt stress and the two levels of salt stress. This analysis also allowed the identification of genotypes exhibiting various levels of tolerance to NaCl. Among the nine genotypes of Triticum durum Desf., cultivar Om Rabiaa was the most tolerant whereas cultivar Mahmoudi genotype was the most sensitive. Following the multivariate analysis of the examined phenotypic and physiological traits, we found that shoot length, shoot fresh weight, leaf area, the whole-plant stable isotope ratio...

Basic and Applied Ecology, 2005

We performed a comparative analysis of two neighbouring chalk hillsides, constituted of mosaics o... more We performed a comparative analysis of two neighbouring chalk hillsides, constituted of mosaics of patches of different secondary successional ages but differing with respect to recent land use history (stable vs. variable). A survey on plant communities was performed with similar design for each site. Multivariate analyses were performed to study the relationships between vegetation and environmental variables so as to interpret the present vegetation variability. Co-inertia analyses show that, in both sites, (1) secondary succession dominates the general pattern of composition gradients in plant communities and (2) succession gradient is strongly connected with soil depth. While soil features are linked to natural variables (altitude) in one site, such link is absent in the other site, suggesting the potential role of past land uses. In order to test this last hypothesis, we performed a partial canonical correspondence analysis (CCA) on an additional data set. Two issues are discussed in the context of a conservation LIFE program: (1) the importance of historical data for the definition of ecosystems of reference, seen as target for restoration and (2) the importance of assessing the long-term influence of past land uses for the definition of conservation management plans.

Additional file 4: of Low genetic diversity despite multiple introductions of the invasive plant species Impatiens glandulifera in Europe

Likelihood values, ΔK values and CLUMPP H values for the different STRUCTURE runs.

Additional file 1: of Low genetic diversity despite multiple introductions of the invasive plant species Impatiens glandulifera in Europe

Description of the loci studied, divided by population. Frequency of null alleles as estimated by... more Description of the loci studied, divided by population. Frequency of null alleles as estimated by the Expectetion Maximization algorithm implemented in FreeNA, and loci with allele frequencies significantly deviating from Hardy Weinberg equilibrium (HWE).

Data from: Low genetic diversity despite multiple introductions of the invasive plant species Impatiens glandulifera in Europe

Background: Invasive species can be a major threat to native biodiversity and the number of invas... more Background: Invasive species can be a major threat to native biodiversity and the number of invasive plant species is increasing across the globe. Population genetic studies of invasive species can provide key insights into their invasion history and ensuing evolution, but also for their control. Here we genetically characterise populations of Impatiens glandulifera, an invasive plant in Europe that can have a major impact on native plant communities. We compared populations from the species’ native range in Kashmir, India, to those in its invaded range, along a latitudinal gradient in Europe. For comparison, the results from 39 other studies of genetic diversity in invasive species were collated. Results: Our results suggest that I. glandulifera was established in the wild in Europe at least twice, from an area outside of our Kashmir study area. Our results further revealed that the genetic diversity in invasive populations of I. glandulifera is unusually low compared to native populations, in particular when compared to other invasive species. Genetic drift rather than mutation seems to have played a role in differentiating populations in Europe. We find evidence of limitations to local gene flow after introduction to Europe, but somewhat less restrictions in the native range. I. glandulifera populations with significant inbreeding were only found in the species’ native range and invasive species in general showed no increase in inbreeding upon leaving their native ranges. In Europe we detect cases of migration between distantly located populations. Human activities therefore seem to, at least partially, have facilitated not only introductions, but also further spread of I. glandulifera across Europe. Conclusions: Although multiple introductions will facilitate the retention of genetic diversity in invasive ranges, widespread invasive species can remain genetically relatively invariant also after multiple introductions. Phenotypic plasticity may therefore be an important component of the successful spread of Impatiens glandulifera across Europe

Soil and Tillage Research, 2020

In this study, we aim to evaluate the respective and combined effect of soil tillage reduction an... more In this study, we aim to evaluate the respective and combined effect of soil tillage reduction and winter cover crops (CCs) on both weed species recruitment and sunflower (Helianthus annuus) yields. By controlling the species composition and propagule pressure of weeds, we tested four soil cover rotation treatments with winter CCs (either Camelina sativa or a winter CC-mix of Leguminosae-Brassicaceae) or nothing (control) followed by a sunflower culture or nothing (control) in combination with two soil preparation treatments (reduced tillage vs. direct seeding) in a randomized complete block design with three replicates per treatment. Our experiment thus comprised 24 experimental units (4 m × 1 m). In each experimental unit, seeds of 40 weed species were sown in May 2017 and seedling emergence was subsequently monitored in mid-July, August and September 2017. We used generalized linear models to analyze the effect of soil cover rotation, soil preparation and the two-way interaction term on species richness, abundance (i.e. number of individuals) and sunflower yield. We additionally used generalized linear mixed-effects models to analyze species relative abundance changes throughout the monitoring period and relative to an exhaustive vegetation survey performed at the beginning of the experiment. Our results show that reduced tillage may increase weed species richness under some circumstances, as well as the abundance of two annual species (i.e. Viola arvensis and Fumaria officinalis). Winter CC-mix reduces the abundance of the most dominant weed species (i.e. the grass Echinochloa crus-galli) while increasing the average weight of sunflower seeds per stem. Irrespective of the tillage treatment, we found that C. sativa favors the presence of patrimonial weed species at the expense of noxious species. We conclude that direct seeding associated with winter CC-mix allows controlling weed abundance while increasing cash-crop yields, and thus meets criteria for a sustainable agriculture.

Annals of botany, 2012

The response of forest herb regeneration from seed to temperature variations across latitudes was... more The response of forest herb regeneration from seed to temperature variations across latitudes was experimentally assessed in order to forecast the likely response of understorey community dynamics to climate warming. Seeds of two characteristic forest plants (Anemone nemorosa and Milium effusum) were collected in natural populations along a latitudinal gradient from northern France to northern Sweden and exposed to three temperature regimes in growth chambers (first experiment). To test the importance of local adaptation, reciprocal transplants were also made of adult individuals that originated from the same populations in three common gardens located in southern, central and northern sites along the same gradient, and the resulting seeds were germinated (second experiment). Seedling establishment was quantified by measuring the timing and percentage of seedling emergence, and seedling biomass in both experiments. Spring warming increased emergence rates and seedling growth in the ...

Divergent regeneration responses of two closely related tree species to direct abiotic and indirect biotic effects of climate change

Forest Ecology and Management, 2015

ABSTRACT Changing temperature and precipitation can strongly influence plant reproduction. Howeve... more ABSTRACT Changing temperature and precipitation can strongly influence plant reproduction. However, also biotic interactions might indirectly affect the reproduction and recruitment success of plants in the context of climate change. Information about the interactive effects of changes in abiotic and biotic factors is essential, but still largely lacking, to better understand the potential effects of a changing climate on plant populations. Here we analyze the regeneration from seeds of Acer platanoides and Acer pseudoplatanus, two currently secondary forest tree species from seven regions along a 2200 km-wide latitudinal gradient in Europe. We assessed the germination, seedling survival and growth during two years in a common garden experiment where temperature, precipitation and competition with the understory vegetation were manipulated. A. platanoides was more sensitive to changes in biotic conditions while A. pseudoplatanus was affected by both abiotic and biotic changes. In general, competition reduced (in A. platanoides) and warming enhanced (in A. pseudoplatanus) germination and survival, respectively. Reduced competition strongly increased the growth of A. platanoides seedlings. Seedling responses were independent of the conditions experienced by the mother tree during seed production and maturation. Our results indicate that, due to the negative effects of competition on the regeneration of A. platanoides, it is likely that under stronger competition (projected under future climatic conditions) this species will be negatively affected in terms of germination, survival and seedling biomass. Climate-change experiments including both abiotic and biotic factors constitute a key step forward to better understand the response of tree species’ regeneration to climate change.

Plant Biology, 2014

Climate change is acting on several aspects of plant life cycles, including the sexual reproducti... more Climate change is acting on several aspects of plant life cycles, including the sexual reproductive stage, which is considered amongst the most sensitive life-cycle phases. In temperate forests, it is expected that climate change will lead to a compositional change in community structure due to changes in the dominance of currently more abundant forest tree species. Increasing our understanding of the effects of climate change on currently secondary tree species recruitment is therefore important to better understand and forecast population and community dynamics in forests. Here, we analyse the interactive effects of rising temperatures and soil moisture reduction on germination, seedling survival and early growth of two important secondary European tree species, Acer pseudoplatanus and A. platanoides. Additionally, we analyse the effect of the temperature experienced by the mother tree during seed production by collecting seeds of both species along a 2200-km long latitudinal gradient. For most of the responses, A. platanoides showed higher sensitivity to the treatments applied, and especially to its joint manipulation, which for some variables resulted in additive effects while for others only partial compensation. In both species, germination and survival decreased with rising temperatures and/or soil moisture reduction while early growth decreased with declining soil moisture content. We conclude that although A. platanoides germination and survival were more affected after the applied treatments, its initial higher germination and larger seedlings might allow this species to be relatively more successful than A. pseudoplatanus in the face of climate change.

A latitudinal gradient in seed nutrients of the forest herb Anemone nemorosa

Plant Biology, 2010

The nutrient concentration in seeds determines many aspects of potential success of the sexual re... more The nutrient concentration in seeds determines many aspects of potential success of the sexual reproductive phase of plants, including the seed predation probability, efficiency of seed dispersal and seedling performance. Despite considerable research interest in latitudinal gradients of foliar nutrients, a similar gradient for seeds remains unexplored. We investigated a potential latitudinal gradient in seed nutrient concentrations within the widespread European understorey forest herb Anemone nemorosa L. We sampled seeds of A. nemorosa in 15 populations along a 1900-km long latitudinal gradient at three to seven seed collection dates post-anthesis and investigated the relative effects of growing degree-hours >5 °C, soil characteristics and latitude on seed nutrient concentrations. Seed nitrogen, nitrogen:phosphorus ratio and calcium concentration decreased towards northern latitudes, while carbon:nitrogen ratios increased. When taking differences in growing degree-hours and measured soil characteristics into account and only considering the most mature seeds, the latitudinal decline remained particularly significant for seed nitrogen concentration. We argue that the decline in seed nitrogen concentration can be attributed to northward decreasing seed provisioning due to lower soil nitrogen availability or greater investment in clonal reproduction. This pattern may have large implications for the reproductive performance of this forest herb as the degree of seed provisioning ultimately co-determines seedling survival and reproductive success.

On the use of weather data in ecological studies along altitudinal and latitudinal gradients

Oikos, 2011

1 On the use of weather data in ecological studies along altitudinal and latitudinal gradients Be... more 1 On the use of weather data in ecological studies along altitudinal and latitudinal gradients Bente J. Graae, Pieter De Frenne, Annette Kolb, Jörg Brunet, Olivier Chabrerie, Kris Verheyen, Nick Pepin, Thilo Heinken, Martin Zobel, Anna Shevtsova, Ivan Nijs and Ann Milbau ...

Journal of Ecology, 2013

1. Macroclimatic variation along latitudinal gradients provides an excellent natural laboratory t... more 1. Macroclimatic variation along latitudinal gradients provides an excellent natural laboratory to investigate the role of temperature and the potential impacts of climate warming on terrestrial organisms. 2. Here, we review the use of latitudinal gradients for ecological climate change research, in comparison with altitudinal gradients and experimental warming, and illustrate their use and caveats with a meta-analysis of latitudinal intraspecific variation in important life-history traits of vascular plants. 3. We first provide an overview of latitudinal patterns in temperature and other abiotic and biotic environmental variables in terrestrial ecosystems. We then assess the latitudinal intraspecific variation present in five key life-history traits [plant height, specific leaf area (SLA), foliar nitrogen: phosphorus (N:P) stoichiometry, seed mass and root:shoot (R:S) ratio] in natural populations or common garden experiments across a total of 98 plant species. 4. Intraspecific leaf N:P ratio and seed mass significantly decreased with latitude in natural populations. Conversely, the plant height decreased and SLA increased significantly with latitude of population origin in common garden experiments. However, less than a third of the investigated latitudinal transect studies also formally disentangled the effects of temperature from other environmental drivers which potentially hampers the translation from latitudinal effects into a temperature signal. 5. Synthesis. Latitudinal gradients provide a methodological set-up to overcome the drawbacks of other observational and experimental warming methods. Our synthesis indicates that many lifehistory traits of plants vary with latitude but the translation of latitudinal clines into responses to temperature is a crucial step. Therefore, especially adaptive differentiation of populations and confounding environmental factors other than temperature need to be considered. More generally, integrated approaches of observational studies along temperature gradients, experimental methods and common garden experiments increasingly emerge as the way forward to further our understanding of species and community responses to climate warming.

Current Forestry Reports, 2016

In Europe, like in many temperate lowlands worldwide, forest has a long history of fragmentation ... more In Europe, like in many temperate lowlands worldwide, forest has a long history of fragmentation and land use change. In many places, forest landscapes consist of patches of different quality, age, size and isolation, embedded in a more or less intensively managed agricultural matrix. As potential biodiversity islets, small forest patches (SFP) may deliver several crucial ecosystem services to human society, but they receive little attention compared to large, relatively intact forest patches. Beyond their role as a biodiversity reservoir, SFP provide important in situ services such as timber and wild food (game, edible plants and mushrooms) production. At the landscape scale, SFP may enhance the crop production via physical (obstacle against wind and floods) and biological (sources of pollinators and natural enemies) regulation, but may, on the other hand, also be involved in the spread of infectious diseases. Depending on their geographic location, SFP can also greatly influence the water cycle and contribute to supply high-quality water to agriculture and people. Globally, SFP are important carbon sinks and are involved in nutrient cycles, thus play a role in climate change mitigation. Cultural services are more related to landscape values than to SFP per se, but the latter may contribute to the construction of community identity. We conclude that SFP, as local biodiversity hotspots in degraded landscapes, have the Curr Forestry Rep (2016) 2:30-44

Can we establish a link between plant and soil microbial diversity? A case study in a chalk grassland in north-western France

Environmental drivers of plant diversity of chalk grasslands in north-western France

Proceedings of 1st International Electronic Conference on Biological Diversity, Ecology and Evolution, 2021

In Europe, chalk grasslands are considered as biodiversity hotspots, hosting rare species (e.g. o... more In Europe, chalk grasslands are considered as biodiversity hotspots, hosting rare species (e.g. orchid and endemic species). However, since the mid 20th century, this habitat is threatened by changes in agricultural practices, especially the decline of pastoralism and recent anthropogenic nitrogen inputs. In this national research project (‘SURPAS’ project, French Ministry for the Ecological Transition, UMS PatriNat, OFB), we aimed to identify the main factors driving plant composition and richness of these chalk grassland communities to update our knowledge and recommendations in terms of conservation measures. The study was carried out in Natura 2000 chalk grassland sites in the valley of Somme river, in north-western France. We performed botanical and habitat surveys (topography and soil measures, vegetation structure, composition and biomass, fodder quality) at two spatial scales, in 1x1 m and 4x4 m plots. Data were analyzed using multivariate analyses (CCA) and mixed models. Ou...