Search bioRxiv⌕ Search

Biology subjects

Buscot, F.

Publications and source records attributed to Buscot, F..

8 recordsLinked to original sources

Plant diversity shapes plant volatile emission differently at the species and community level

Studies have investigated the interactions between plants through competition and resource sharing to understand the mechanisms behind the positive effects of plant diversity on productivity. Volatile organic compounds (VOCs) are important info-chemicals in plant-plant interactions, but they have so far rarely been considered in this context. Here, we measured VOC emissions at both community and species levels (Plantago lanceolata) in experimental plant communities of varying diversity (The Jena Experiment) to understand the role of VOCs in driving biodiversity-ecosystem functioning relationships. We show that plant diversity determines the release of plant VOCs at both levels. At the community level, plant species richness directly enhanced VOC emission and increased VOC richness both directly and indirectly by altering herbivore damage and LAI. At the species level, plant diversity did not directly affect the VOC emissions of P. lanceolata but indirectly affected it by influencing the VOC emissions from the surrounding community. Plantago lanceolata individuals in communities with high concentrations of green leaf volatiles decreased their VOC emission, while those in communities with high concentrations of terpenoids increased their VOC diversity. Our results provide first evidence that plant diversity shapes community-level plant VOC emission and thus influences focal plant VOC emission inside the community.

ecology↗

Resource economics of tree communities control soil food web multifunctionality in European forests

Plants affect terrestrial ecosystem functioning by performing the primary production that energetically sustains heterotrophic organisms1, and by shaping the microenvironment2. However, the influence of plant diversity and community composition on ecosystem functioning through their effects on energy flow into food webs has been little studied3,4, especially for soil food webs that channel most of the plant-derived energy1,5. Applying a food web energetics approach6,7, we show that the resource economics of dominant tree species control soil food web multifunctionality across European forests. Specifically, tree communities dominated by resource acquisitive species promoted faster rates of multiple soil trophic functions simultaneously than did those dominated by resource conservative species. This was primarily driven by their production of plant litter with higher nutritional quality and their warmer forest microclimate, leading to a higher metabolic activity of soil organisms8. Tree species mixing had rather weak and negative effects on soil food web multifunctionality, mostly due to a shift in the resource-based energy channeling from living plant fine roots to litter and a cooling effect on the forest microclimate. Tree diversity effects were largely outweighed by community compositional effects, which were of similar magnitude to the effects of biogeographic differences among locations. Our findings emphasize the importance of plant functional traits related to resource economics as drivers of plant community effects on soil food web functioning5,9 and highlight the consequences that climate-driven shifts in tree community composition could have for forest soil functioning.

ecology↗

Common soil history is more important than plant history for arbuscular mycorrhizal community assembly in an experimental grassland diversity gradient

The relationship between biodiversity and ecosystem functioning strengthens with ecosystem age. However, the interplay between the plant diversity - ecosystem functioning relationship and Glomeromycotinian arbuscular mycorrhizal fungi (AMF) community assembly has not yet been scrutinized in this context, despite AMFs role in plant survival and niche exploration. We study the development of AMF communities by disentangling soil- and plant-driven effects from year effects. Within a long-term grassland biodiversity experiment, the pre-existing plant communities of varying plant diversity were re-established as split plots with combinations of common plant and soil histories: split plots with neither common plant nor soil history, with only soil but no plant history, and with both common plant and soil history. We found that bulk soil AMF communities were primarily shaped by common soil history and additional common plant history had little effect. Further, the steepness of AMF diversity and plant diversity relationship did not strengthen over time, but AMF community evenness increased with common history. Specialisation of AMF towards plant species was low throughout giving no indication of AMF communities specialising or diversifying over time. The potential of bulk soil AMF as mediators of variation in plant and microbial biomass over time and hence as drivers of BEF relationships was low. Our results suggest that soil processes may be key for the build-up of plant community-specific mycorrhizal communities with likely feedback effects on ecosystem productivity, but the plant-available mycorrhizal pool in bulk soil itself does not explain the strengthening of BEF relationships over time.

microbiology↗

A fast-slow trait continuum at the level of entire communities

Across the tree of life, organismal functional strategies form a continuum from slow-to fast-growing organisms, in response to common drivers such as resource availability and disturbance. However, the synchronization of these strategies at the entire community level is untested. We combine trait data for >2800 above-and belowground taxa from 14 trophic guilds spanning a disturbance and resource availability gradient in German grasslands. Most guilds consistently respond to these drivers through both direct and trophically-mediated effects, resulting in a slow-fast axis at the level of the entire community. Fast trait communities were also associated with faster rates of whole ecosystem functioning. These findings demonstrate that slow and fast strategies can be manifested at the level of whole ecosystems, opening new avenues of ecosystem-level functional classification.

ecology↗

Effects of recurrent summer droughts on arbuscular mycorrhizal and total fungal communities in experimental grasslands differing in plant diversity and community composition

Biodiversity loss and climate change have been determined as major global drivers affecting ecosystems and their functioning. In this context, drought was shown to have negative effects on ecosystems by disrupting ecological processes, which could be buffered in more biodiverse systems. Many studies, however, focus on effects on aboveground communities of single drought events, while dynamics of soil-borne communities are still widely unclear, despite their important roles in ecosystem functioning. To elucidate the effect of recurrent summer drought periods on fungal communities in a long-term grassland biodiversity experiment, roof shelters were installed on grassland plots ranging in plant species richness from 1 to 16 species and plant functional group richness (1-4 groups) and composition. After 9 years of summer droughts, bulk soil was sampled and used for Illumina sequencing of the ITS2 and SSU genes to characterize the total fungal and arbuscular mycorrhizal fungal (AMF) communities, respectively. We found shifts of AMF and total fungi community structures caused by recurrent drought and plant species richness, but no buffering of drought effects by plant diversity. Alpha-diversity (VT or ASV richness) of both AMF and total fungi increased with plant species richness but was not significantly affected by drought. Even though drought overall had minimal long-lasting effects, we found Diversispora and Paraglomus among the AMF and Penicillium among total fungal communities to be more abundant after the drought treatment. AMF communities were affected by the presence of individual plant functional groups, reacting stronger to presence of legumes under drought, while total fungal interaction with plant communities were similar under drought as control. AMF -diversity differed between plant functional groups in control conditions but was independent of plant community composition under drought. In contrast, total fungi -diversity was increased by presence of herbs and legumes only under drought. From our results, we conclude that recurring moderate summer droughts do not strongly affect soil fungal communities. All shifts can be explained by indirect effects through the plant community and its top-down effect on soils altered by drought. Further, AMF are not less affected than total fungal communities, but rather respond differently by interacting more strongly with legumes in response to drought. Consequently, not plant species richness, but plant functional composition, dominates in shaping fungal communities under recurrent droughts.

ecology↗

Distinct effects of host and neighbour tree identity on arbuscular and ectomycorrhizal fungi along a tree diversity gradient

Plant diversity and plant-related ecosystem functions have been in focus in biodiversity-ecosystem functioning studies. However, in this context, biotic interactions with mycorrhizal fungi have been understudied although they are crucial for plant-resource acquisition. We investigated the effects of tree species richness, tree mycorrhizal type on arbuscular (AMF) and ectomycorrhizal fungal (EMF) communities. We aimed to understand how dissimilarities in taxa composition and beta-diversity are related to target trees and neighbours of the same/different mycorrhizal type. We sampled a tree experiment with saplings ([~]7 years old), where tree species richness (monocultures, 2-species, and 4-species mixtures) and mycorrhizal type were manipulated. AMF and EMF richness significantly increased with increasing tree species richness. AMF richness of mixture plots resembled that of the sum of the respective monocultures, whereas EMF richness of mixture plots was lower compared to the sum of the respective monocultures. Specialisation scores revealed significantly more specialised AMF than EMF suggesting that, in contrast to previous studies, AMF were more specialised, whereas EMF were not. We further found that AMF communities were little driven by the surrounding trees, whereas EMF communities were. Our study revealed the drivers of mycorrhizal fungal communities and further highlights the distinct strategies of AMF and EMF.

ecology↗

Strong positive biodiversity-productivity relationships in a subtropical forest experiment

Forest ecosystems contribute substantially to global terrestrial primary productivity and climate regulation, but, in contrast to grasslands, experimental evidence for a positive biodiversity-productivity relationship in highly diverse forests is still lacking1. Here, we provide such evidence from a large forest biodiversity experiment with a novel design2 in subtropical China. Productivity (stand-level tree basal area, aboveground volume and carbon and their annual increment) increased linearly with the logarithm of tree species richness. Additive partitioning3 showed that increasing positive complementarity effects combined with weakening negative selection effects caused a strengthening of the relationship over time. In 2-species mixed stands, complementary effects increased with functional distance and selection effects with vertical crown dissimilarity between species. Understorey shrubs reduced stand-level tree productivity, but this effect of competition was attenuated by shrub species richness, indicating that a diverse understorey may facilitate overall ecosystem functioning. Identical biodiversity-productivity relationships were found in plots of different size, suggesting that extrapolation to larger scales is possible. Our results highlight the potential of multi-species afforestation strategies to simultaneously contribute to mitigation of climate change and biodiversity restoration.

ecology↗

Young Genes To The Front -- A Strategy For Future Resistance Against Powdery Mildew?

Nonhost resistance of a plant against a microbial pathogen can be the result of a long-lasting coevolutionary optimization of resource allocation in both host and pathogen. Although this has been suggested for years, coevolutionary aspects leading to nonhost resistance in plants are not fully understood yet. Instead, most studies focus on limited subsets of genes which are differentially expressed in infected plants to describe details of defense strategies and symptoms of diseases.\n\nHere, we exploit publicly available whole genome gene expression data and combine them with evolutionary characteristics of genes to uncover a mechanism of host-pathogen coevolution. Our results suggest that metabolic efficiency in gene regulation is a key aspect leading to nonhost resistance. In addition, we find that progressing host-pathogen coevolution is accompanied by subtle, but systematic overexpression of recently founded genes. In support of our plant-specific data, we observe similar effects in animal species.

evolutionary biology↗