Functional aspects of biodiversity in relation to plant health

Abstract: The most visible impact of human activities on biodiversity concerns species which arepart of our cultural heritage but a huge part of the species are still undescribed, mainly those inthe ocean, in extreme environments and of course in the soil where the damage caused byanthropogenic activities are unknown. Although some estimation can be proposed, they are allVconsidered as under-evaluations of the putative number of taxa that could be present on the planetEarth. Despite it is not yet known how, this biodiversity contributes to different services throughthe functioning of ecosystems, and thus influences the sustainability of these ecosystems. At asmaller scale, the one we can approach in the frame of this workshop, it is clear that biodiversityis shaped by farmed ecosystems but in return, the organisms building up the communitycontribute directly to the farmed ecosystems, via the regulation of parasites and diseases of cropsand the contribution to the fertility of the soils and to soil health. It seems therefore essential tounderstand the nature of the interactions between biodiversity and agriculture to both preserve theformer and improve the latter. So far, none of the various indices used to measure the diversitycan be used as an indicator of the soil health, and the relation between diversity and soilfunctioning is still difficult to understand. Sound use of agriculture practices should allow us tocontrol harmful organisms without eroding the biodiversity of these interacting components.