Our research interests focus on three main objectives: (1) to develop new mathematical approaches to biodiversity data analysis and modeling; (2) to better understand the ecological, evolutionary and historical processes that shape biodiversity patterns through complementary approaches (in particular functional and evolutionary ecology and biogeography) from the local scale to the planet in terrestrial and aquatic environments; (3) to contribute to conservation strategies on the basis of the processes that maintain and create biodiversity. Our studies will be organized in three inter-connected tasks:

 

Task 1. Theoretical & Methodological developments — Our approaches involve mathematical modeling and analysis of observed data including citizen-science programs, experimental data and large databases.

• Quantifying biodiversity. We will contribute to the definition of biodiversity indices and indicators and to their monitoring in space and time. Depicting multiple facets of biodiversity is essential to disentangle the processes that shaped, shape and will shape species assemblages in relation with human impacts. We will further develop comparative analyses of three facets of biodiversity – species diversity, functional diversity and phylogenetic diversity – with the aim to better disentangle ecological from evolutionary and historical processes.

• Spatio-temporal analyses. Local community ecology and large-scale biogeography are often uncoupled. One of the originalities of our approach will be to take into account processes at large scales such as speciation/extinction, colonization or evolution of biological traits in the study of local species communities, and inversely to determine how local, transient processes might durably impact biodiversity patterns on a global scale. We aim to develop approaches centered on the study of temporal variability of natural systems and trait evolution in communities, to evaluate and explain the stability of ecosystems and the sustainability of the services they provide.

• Interaction networks. An important part of our research tackles interactions among species, notably through the study of trophic and mutualistic networks. Most studies focus on temporally aggregated interaction networks, totally ignoring the seasonal dynamics. Taking species phenology into account is necessary to understand the role of the structure and dynamics of these networks in the stability of ecosystems and their services, and to evaluate the consequences of human-driven changes on these networks. We aim to develop new dynamic models of interaction networks explicitly integrating species phenology.

 

Task 2. Applications — We work on macro-organisms, including among others plants, algae, arthropods, fish, amphibians, reptiles, birds and mammals in a variety of ecosystems (terrestrial ecosystems, freshwater and marine waters) including gradients of anthropogenic impact.

• In terrestrial ecosystems, our research currently addresses the links between biodiversity, climate, land use, and human practices (exploitation-protection) at multiple spatial scales using citizen monitoring data (e.g. Vigie-nature, CRBPO biometric). In the coming years, we will tackle understudied taxonomic groups using recent monitoring programs (bats, pollinators, soil invertebrates, Orthoptera…). For example, we will assess the rate of response to climate warming in plant communities, for which there are surprisingly few standardized monitoring programs. We will tackle understudied anthropogenic drivers of biodiversity changes, such as new agricultural practices (e.g. no-till), light pollution, and wind turbines. We will also look for hierarchizing pressures by disentangling how the interactions of different drivers (climate, land use, practices like hunting) affect the responses of diversity facets: for example how the reduction or control of global threats (land use, landscape management, protections) on biodiversity could facilitate climate change adaptation.

• In freshwater ecosystems, we study the structure of taxon assemblages according to trophic and environmental conditions. We use empirical and experimental approaches; we study the stability of fish communities and the installation of rare species in artificial experimental lakes. These studies will allow us to identify the place of rare and original species in the functioning of an ecosystem. We study congruences between the structure of intestinal communities and the structure of fish communities in water bodies and micro-macroorganisms.

• The status of marine ecosystems is more often summarized as a status of exploited stocks than as the state of the whole ecosystem. Our aim is to use functional, trophic and ecological approaches for a better knowledge of fish, cephalopod, and crustacean communities and of their spatio-temporal dynamics, in systems impacted by fishing activities. In this endeavor, we will use biological traits to assess the vulnerability of taxa to fishing pressure and to depict the community structure over an environmental and/or fishing pressure gradient. In the context of the Common Fisheries Policy, we will also use a trait-based approach to shed light on the mechanisms underpinning the efficiency of selectivity devices and their putative consequences on community structure. Using available times-series of marine resources along French coasts (in collaboration with IFREMER), we will further investigate temporal changes in the functional and phylogenetic structure of marine communities in relation to environmental changes and fishing intensity. We will examine whether community diversity begets stability. In addition to using available datasets, we intend to develop citizen monitoring programs in marine ecosystems on taxonomic groups less monitored at large scale (algae, invertebrates) exploring the possible use of novel technologies (images, acoustic recordings).

 

Task 3. Contributions to conservation strategies — Our analyses concern the impacts of human activities on biodiversity patterns and dynamics. Most conservation strategies focus on species and population dynamics. In the near future, we will instead concentrate on the preservation of ecological functions and on the roles the concepts of phylogenetic diversity and phylogenetic signal might play in this preservation, by combining complementary approaches. First, we have recommended giving conservation priority to phylogenetically or functionally original species, assuming that these species have rare biological characteristics. We will identify such species, analyze the link between phylogenetic and functional originality and assess the origin and geographic distribution of original species. Second, we will quantify the amount of functional and phylogenetic diversity protected or restored by conservation measures, such as translocations. Third, we will work on the link between biodiversity, ecosystem functions and services, with a strong focus on pollination, for which we have accumulated promising datasets. Pollination has become a prominent social issue, present in the media and government spheres, through two main facets: the pollination of crops and the decline of honey bees. Yet the effectiveness of pollination is not easily measured at large spatial scales, and honeybees are not the only pollinators. We aim to broaden the debate by (1) developing a new index of pollination effectiveness on the basis of crop yield data, which help target areas with an actual pollination deficit and (2) by including other less well-known pollinating insects using monitoring programs such as SPIPoll (http://www.spipoll.org/), the “Observatoire Agricole de la Biodiversité” and the two butterfly monitoring programs of Vigie-nature (http://vigienature.mnhn.fr/).