Forces structuring biodiversity in agricultural field margins: understanding metacommunities and plant-insect interactions across an agricultural intensification gradient – AgriBiodiv

In this project, we will study the patterns of diversity, including functional diversity, on the margins of agricultural fields across a gradient of intensification of agricultural practices at the national level in France. We will take advantage of an already existing monitoring effort (500-ENI network, with more than 500 plots monitored yearly since 2012) to: (1) create a molecular barcode library and fine-tuning a metabarcoding protocole to identify coleopteran species in a mixed pool at a reasonable price and without further need of taxonomic expertise, dedicated to beetles in agricultural landscapes, to facilitate monitoring efforts in the future; (2) study the potential effects of agricultural practices on plant and coleopteran diversity along agricultural intensification gradients; and (3) characterize the links between plant and coleopteran diversity, including trophic links, and direct and indirect effects between environmental gradients (including agricultural practices), plant and coleopteran diversities. Our main hypotheses are related to the relative effects of agricultural practices on biodiversity when biodiversity includes life history traits and ecological characteristics of species. With this study we hope to gain a more mechanistic understanding of the interplay between local to regional agricultural practices and the effects that they may have on biodiversity in field margins. This project will add value to ongoing monitoring efforts, and contribute to the understanding of the links between agricultural practices and the surrounding biodiversity, which is a fundamental element in proposing sustainable agricultural practices at the national level, in line with the goals of maintaining agricultural yield while reducing the impact of agriculture on biodiversity.
This project is uniquely positioned to deliver fundamental insights and impacts in at least three ways. First, the combination of scale of analysis (local to national level) and the integration of data on primary producers (plants), secondary and tertiary consumers (coleopteran communities) and field management is unprecedented in the agroecological literature, especially when considering some of the groups of beetles that have been overlooked before (e.g. weevils and leaf beetles). Unlike the few other published national-level analyses of agricultural intensification effects on biodiversity, here we have access to real-time direct information of the agricultural management practices near the monitoring sites, so we do not need to rely on large-scale proxies to relate biodiversity and agricultural management. Second, by taking advantage of an existing national monitoring effort, we gain access to and co-opt a network of stakeholders that are already receptive to new knowledge, and which will allow rapid and efficient dissemination into agricultural practices at the national level. Third, our development of the agricultural coleopteran barcoding library and accompanying metabarcoding protocol would be a hugely valuable tool in 500-ENI’s future monitoring efforts. These protocols will elevate the accuracy, efficacy and cost-effectiveness of future regular species monitoring at the national level.
We expect to produce several scientific publications in high-ranking journals as a result of the unique value of the analyses, as well as regular outreach publications for agronomists involved in the 500-ENI network and elsewhere. The project will also result in the training of a doctoral student, a postdoctoral fellow, and several master and BTS students, with multiple potential networking opportunities for them in an environment that is rich in scientific and applied interactions. It will also contribute to cataloguing coleopterans in agricultural settings, adding to the existing entomological collection at the CBGP, which already serves as a reference at the European level.