In order to explain why species decrease, the natural and unnatural changes in the living communities in which these species live must be understood. In addition to the amount of species in these communities, it also concerns how many of the individuals of these species occur in such a community (abundance). This requires large and detailed datasets of living communities from empirical situations. However, these types of datasets are rare and very expensive to obtain. This is due to the current morphological techniques with which these datasets are collected. BioMon partner CML focuses in this research on modeling the relationship between DNA present in an environment and the density of the species from whom that DNA comes. The ultimate goal is to be able to determine and monitor via DNA fast, easy and standardized densities of species in and total living communities.