With the destruction and fragmentation of habitats, direct harvesting of organisms, climate change, changes in biogeochemical cycles, pollution and, finally, biological invasions, humans have probably triggered the 6th wave of mass extinctions of biodiversity. Beyond the ethical questions associated with the impact of humans on their environment, ecologists have identified the harmful consequences of biodiversity loss on the very functioning of ecosystems and the services they provide to our societies. Diversity plays a very important role in ecosystem functioning and the nature of the assemblages of organisms within ecosystems is central to understanding the mechanics of ecosystems. Ecologists use the term "functioning" to refer to the biotic and abiotic properties and/or processes within ecosystems, such as recycling or biomass production. Services" are all the benefits that human populations obtain from ecosystems, including food production, biological control, pollination, etc. Recent work has also clearly demonstrated the link between the biological and economic aspects of biodiversity. This crisis of mass extinctions has motivated two decades of research to understand more clearly the relationship between biodiversity and ecosystem functioning. This effort has required a synthesis between several sub-disciplines of ecology, mainly community and ecosystem ecology.