**1. Introduction**

In this chapter we present a brief history of studies on the relationship between biodiversity and ecosystem functioning (BEF), describing the main models used to explain this relationship, as well as the biodiversity metrics most commonly used. Furthermore, we use litter decom‐ position as a "process model", presenting a flowchart of mechanisms that may affect the decomposition. The flowchart represents the linking between the diversity of leaves that compose the litter, which is usually called the litter mixture, to its decomposition rates. Finally, we present a simplified flowchart of the edaphic trophic web, relating it to litter decomposition, and some perspectives for future studies in this area.
