Biotic Impoverishment Weakens While Biotic Enrichment Strengthens the Functioning of Natural Systems and the Services They Provide
All functions of ecological systems, across all scales in space and time, are governed by the biota present. Biodiversity and Ecosystem Functioning is the discipline that focuses on the significance of the biota being diverse, not just abundant. That is, if, for a given volume of space on Earth, for a given biomass, if one were to alter the taxonomic, functional, phylogenetic, genetic, or other dimension of diversity of the biota occupying that volume, we ask if there would be a predictable change in function.
This question is surprisingly difficult to answer.