Biodiversity : from individuals to community

Several research directions have been identified to address biological diversity across multiple levels of organization.

1. Fine-scale diversity (individual level)

This approach focuses on phenotypic variation and individual specialization to quantify both intra- and inter-individual diversity within populations. It aims to improve understanding of population dynamics, their adaptive responses to environmental change, and their cascading effects on other biological compartments.

2. Population-level diversity (genetic approach)

This level involves characterizing the genetic structure of selected species in order to evaluate their vulnerability to environmental change and anthropogenic pressures, as well as their adaptive potential. This information is intended to inform conservation strategies and risk management, particularly in relation to different uses of lake ecosystems.

3. Ecological interactions

Ecological studies consider both trophic and non-trophic interactions.

3.1 Trophic interactions

This involves modelling food webs and assessing their responses to environmental change and biological invasions. Food webs are used as multi-trophic diagnostic tools to evaluate ecosystem disturbances. This approach combines food web reconstruction with paleolimnological data to better integrate key indicator groups of lake ecosystem quality and to investigate species interdependencies, as well as the propagation of trophic effects through ecological networks (cascade effects).

3.2 Non-trophic interactions

This focuses on characterizing the microbiome (bacterial communities) and potentially the virome (viral communities) associated with microalgae, particularly cyanobacteria, with the aim of improving predictions of plankton dynamics, which are often highly variable and difficult to anticipate.

Specific research goals currently at work can be summed up as follows:

> Characterizing functional diversity of benthic prokaryotes and role in the methane cycle (in relation to local and global pressures)
> Estimating the role of a variety of microbes including microbial parasites (viruses, bacteria, chytrids and protists) on the dynamics of ecological groups such as primary producers, zooplankton and fish
> Replacing microbial communities in trophic network models and assessing their influence on the carbon fate especially within the pelagic compartment
> Assessing the diversity and influence of the secondary metabolites produced by primary producers (chemical ecology) on the ecological communities and trophic functioning in biotic interactions
> Addressing the impacts of invasive non-native species on lake food webs and quantifying their direct and indirect ecological consequences