Résumé
Biodiversity changes associated with the anthropogenic alteration of natural environments have been hypothesized to enhance disease transmission and to facilitate the emergence of infectious diseases. This chapter reviews the various links that may occur between biodiversity and disease transmission on scales ranging from global to local and the likely ecological mechanisms. The consequences of land usage and land cover changes on disease transmission are formulated through the overall effects on biodiversity observed from long-term observatories. Habitat fragmentation should lead to reduced diversity of pathogen species and changes in pathogen prevalence as proposed by the "perturbation hypothesis." However, habitat fragmentation that leads to increased edge, and increasing contacts between different communities of reservoirs and vectors, should increase disease transmission and pathogen prevalence according to the "pathogen pool diversity" hypothesis. Network analyses represent new tools to investigate disease transmission in a changing biodiversity context, i.e., changes in multiple hosts-multiple parasite interactions. Finally, this review advocates for manipulative experiments, theoretical studies, and long-term data collection in ecological observatories that will help in building scenarios of future health.