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Temperature inducible phenotypic plasticity is a major player in plant responses to climate warming. Functional responses and their role in determining thermal plasticity of plants remain poorly understood. Our objective was to compare trait responses of six populations of Ludwigia peploides resulting from seed from Oceanic climate and from Mediterranean climate after an exposure at three temperatures (16, 24, and 30°C). A comparative analysis showed that at 30°C, the six populations of L. peploides shared different morphological responses, whereas a common pattern of morphological responses was found for the six populations at 16°C. At 16°C, the growth was very low suggesting a stress. At 30°C, the three Mediterranean populations of L. peploides accumulated ≈ sevenfold more total biomass than the populations from Oceanic region. Despite drawing similar response pattern to temperature, the populations showed several different metabolic responses. The thermal plastic responses to the highest temperature differed according to the origin of the populations. The Mediterranean populations of L. peploides could be better adapted to rising temperature. These abilities could allow them to take advantage from climate warming if the temperature is not warming up to temperature above a critical threshold. [ABSTRACT FROM AUTHOR]

Background and aims: Considering the plant microbiota, temporal changes are expected depending on plant development stages and environmental pressures because of modifications in plant requirements and available soil microbial reservoir. Methods: Herein, we analyzed the composition of root endosphere microbiota of grafted vine plants using two grapevine cultivars (Merlot and Cabernet-Sauvignon as scion grafted on rootstocks of different clones) as models both sampled in a single vineyard at three dates over a period of two growing years. Results: Highly conserved temporal patterns were found in the two cultivars. Intra-annual changes in microbial community composition were recorded whereas convergent microbial communities were observed on the two September dates. In particular, the increase in Actinobacteria and decrease in Glomeromycota in September were interpreted as shifts in the microbiota community patterns related to plant physiological requirements (e.g. water supply). A high proportion of non-random assembly of the root endospheric bacterial community confirmed the deterministic influence of the plant or/and the environment in microbial recruitment over time. The modified normalized stochasticity ratio (MST) showed that deterministic processes of assembly (MST < 50%) were commonplace despite the changes in the root microbiota composition observed among sampling dates. Conclusion: Our study suggests an intra-annual rhythm of microbiota shifts, marginally random, with a succession within the root-microbiota endosphere likely governed by active plant filtering. A better knowledge of microbial-recruitment at work, seems important for both fundamental and applied perspectives. [ABSTRACT FROM AUTHOR]

Most studies that have explored the effect of biological control in maintaining pest populations at acceptable levels have focused on the ability of natural enemies to reduce pest abundances. The reduction in pest populations induced by natural enemies, however, is rarely studied in association with the incidence of viruses transmitted by pests, as well as its impact on crop damage and yield. Here, we performed large-scale winter field monitoring to assess the direct and indirect effects (via arthropod natural enemies) of flower strips along cereal crop margins, on (i) cereal aphid abundance, (ii) the incidence of barley yellow dwarf viruses (BYDVs) transmitted by aphids in autumn and winter, (iii) crop damage, and (iv) crop yield. In 28 cereal fields (over 2 years), we used a paired experimental design to compare a cereal field edge directly adjacent to a flower strip with an opposite (at least 50 m apart) cereal field edge adjacent to a grassy margin. Our results highlight that winter flower strips favoured the activity of ground arthropod predators in the adjacent cereal field but not aphid parasitism rate in winter. Parasitism rate only increased with the complexity of the surrounding landscape. Our results also showed that flower strips reduced both vector abundance and virus incidence in the adjacent cereal field in winter but did not affect virus symptom levels or yields. Damages were low and yield remained high in our study, which may encourage farmers to stop insecticides during the autumn-winter. This study provides a first example of how flower strips along field edges can decrease the incidence of a vector-borne virus in winter and could be used as a strategy to promote more sustainable agriculture. [Display omitted] • Flower strips decrease aphid abundance and BYDV virus incidence and increase predator abundance in winter. • Lower abundance of aphids could result from a direct effect of flower strips or via their natural enemies. • BYDV infected aphids were more parasitized. • Yield and damages were not increased but remain high. [ABSTRACT FROM AUTHOR]

Agricultural intensification has been demonstrated to induce a loss of biodiversity. Despite the key role of symbiotic microorganisms in plant nutrition and protection, the impact of agricultural intensification on these microorganisms is not fully understood. Organic farming and field edges (as semi-natural elements) may promote a higher microbial diversity thanks to lower anthropic disturbance and higher plant diversity. We sampled wheat individuals in pairs of wheat fields (one organic and one conventional) along a distance gradient to the edges (hedgerow vs. grassy), in 20 landscape windows selected along an uncorrelated gradient of organic farming and hedgerow density. We demonstrated that organic farming shaped microbial composition and increased fungal and bacterial richness, while hedgerows had a neutral or negative effect on richness depending on the microbial phyla considered. In contrast to bacteria, fungal communities were heterogeneously distributed within fields, having a higher diversity for some phyla close to field edges. Overall we highlighted that fungi responded more to the field scale while bacteria were more affected by landscape scale. The effect of agricultural intensification on plant microbiota and therefore on the functions provided by microorganisms to the plants has to be considered at a multiple spatial scale—from field to landscape. [ABSTRACT FROM AUTHOR]

Question: Habitat isolation is a major driver of biodiversity because it affects dispersal among local communities, especially for plants. Corridors are supposed to facilitate the movement of organisms and hence their effective dispersal, thereby increasing biodiversity. Hedgerows provide favorable habitats for forest plant establishment, but their role in dispersal among forest patches is still unknown. In addition, seeds can be more predated within hedgerows because animal movement is also encouraged by these corridors. We aimed to answer the question: Are plant dispersal and seed removal by animals in connected hedgerows compared with unconnected hedgerows promoted for forest plant species? Location: Long‐term ecological site “Zone Atelier Armorique”, western France (ca. 150 km2). Methods: We analyzed seed dispersal along two pathways in 16 woodlots: connected (least‐cost pathways, i.e., optimal corridors); and unconnected high cost pathways (absence of corridor). Using a trap study, we first quantified seed rain and analyzed seed composition after trapped seeds were germinated in the greenhouse. At the same sampling points, we then analyzed the rate at which two different sized seeds were removed from seed baits by animals. Results: Our results revealed no difference in the number of trapped seeds in connected and unconnected pathways, but did reveal a difference in the number and richness of viable seeds, with corridors having a positive impact. In the predation experiment, the rate of removal of small seeds was higher in connected pathways than in unconnected pathways. Conclusion: Connectivity enhanced the dispersal of viable forest plant species but also the predation of small seeds, which possibly played a role in their subsequent dispersal. This work highlighted the effect of connectivity on seed dynamics within hedgerows and improves our understanding of the role of hedgerows as stepping‐stones for seed dispersal among forest patches.Landscape connectivity influenced seed dynamics within hedgerows. It enhanced the dispersal of viable forest plant species in hedgerows but also increased the predation of small seeds, which possibly played a role in their subsequent dispersal. This work highlighted the role of hedgerows as stepping stones for seed dispersal among forest patches.. [ABSTRACT FROM AUTHOR]

Understanding the assembly rules of mycorrhizal fungi is crucial, given their tremendous importance in plant nutrition and health. Differentiation in plant‐associated arbuscular mycorrhizal fungi (AMF) is likely driven by a host‐preference effect. Coexisting plant species may then affect a focal plant microbiota through fungal dispersal among plants, and plant preferential recruitment of AMF. Both mechanisms are likely shaped by the plant's phylogenetic and functional strategies.We expected that (a) the structure of AMF assemblages associated with a focal plant depends on the identity of the neighbouring plant species; (b) this effect would be predicted by the phylogenetic and functional similarity between the focal and neighbouring plant species. These predictions were tested during the first stages of growth, by simulating the early development of plants within a communityUsing an experimental matrix‐focal plant species design testing 15 neighbouring plants from five taxonomic families, we demonstrated that the neighbouring plants provided different species pools for the focal plant, Medicago truncatula, and influenced AMF communities associated with focal plant, especially in terms of richness but not relative evenness. Medicago truncatula grown with Brassicaceae or other Poaceae species displayed respectively no or low AMF richness compared to those grown with Rosaceae and Asteraceae species. These effects were weakly dependent on the phylogenetic distance from the neighbouring plant but were predicted by the functional proximity. AMF assemblages were enriched and bore more resemblance to the neighbouring plants when the neighbouring plants were functionally dissimilar from the focal one. Functional dissimilarity was only a significant predictor when based on traits characterizing the nutrient use and uptake strategy rather than on a more integrated growing strategy of the plant.Microbiota composition was shown to be dependent on the identity of the neighbouring plant, particularly on its functional below‐ground niche. At the colonization stage, when the plant arrives in a community, plant mycobiota might be influenced by the spatial distribution of plants already present in the community. This work suggests a new view of the concept of niche partitioning in space for plants based on microorganism–plant interactions. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

Aim: An individual tree resembles a living island, a small spatially distinct unit upon which colonizers maintain populations. However, several differences exist compared to oceanic islands: a tree is relatively young, is composed of numerous differently aged branches, may be phylogenetically isolated from neighbours, and some of its colonizers are specific to particular tree lineages. We suggest that these specificities strongly affect both alpha‐ and beta‐diversity within trees, including positive effects of isolation on the diversity of generalists, and strengthening of the effect of isolation with tree age. Location: Rennes, Bretagne, Western France Taxon: Little‐dispersive, generalist oribatid mites (Acari) and highly dispersive, specialist gall wasps (Hymenoptera: Cynipidae) on oak (Quercus sp.) trees. Methods: We tested the effects of tree and branch age, tree and branch habitat diversity, and tree phylogenetic isolation on per‐branch and per‐tree alpha‐diversity, and on within‐tree beta‐diversity of both taxonomic groups. Results: For gall wasps, no variable explained diversity patterns at any level. In contrast, for oribatid mites, we found that high phylogenetic isolation of trees and high branch age increased alpha‐diversity per tree and per branch (in young trees) as well as turnover among branches. High tree age decreased alpha‐diversity per branch (in phylogenetically isolated trees) and increased turnover among branches. Increasing habitat diversity increased alpha‐diversity per tree, but decreased alpha‐diversity per branch (in young trees). Main conclusions: For mites, contrary to common expectation, we suggest that: (a) phylogenetically distant neighbours are a source of immigration of distinct species and (b) with the increase of tree age, species‐sorting results in a few species colonizing and dominating their preferred patches. In gall wasps, strict specialization on oaks, and efficient dispersal may render oak age or isolation unimportant. The positive relationship between isolation and within‐tree turnover is a new contribution to biogeography in general. [ABSTRACT FROM AUTHOR]

Abstract: In the context of rapid and severe biodiversity decline in agroecosystems, the European Union has introduced agri-environmental schemes. However, these schemes require evaluation to estimate their efficiency, for further consolidation and improvement. The establishment of grassy strips along watercourses represents a measure of cross-compliance introduced in France in 2005. In this study, we analyzed the benefits of these new landscape elements for biodiversity, by (i) exploring the plant community composition of grassy strips in relation to their landscape context, (ii) analyzing the faunal communities of three major functional groups (i.e., small mammals, syrphids, and carabid beetles) present in grassy strips of agroecosystems, (iii) comparing the faunal biodiversity to that observed in other habitats of agroecosystems, such as fields and hedgerows, and (iv) investigating the relationships between faunal community indices and grassy strip properties. The results of our study showed that the plant community of grassy strips is mainly influenced by semi-natural habitats that are present within a landscape context, i.e., at a scale >500m. We found that grassy strips do not necessarily present areas of particularly high animal biodiversity compared to other habitats (i.e., fields and hedgerows). However, the properties of these strips (i.e., length, width and plant biodiversity) influence the structure of faunal communities. Two years after the establishment of grassy strips, their role as ecotones between previous field margins (mostly hedgerows in our study site) is illustrated through the response of the fauna. Hence, grassy strips, being more stable than cultivated fields, contribute to a new refuge within the agroecosystem landscape. [Copyright &y& Elsevier]