Applied Biodiversity Metrics; Concepts to Choose Them Well

The evaluation of biodiversity is an essential tool for conservation, management of natural resources, and assessment of ecosystem functioning. Choosing an appropriate and understandable diversity metric is critical to ultimately make better decisions and apply more sustainable resource management. However, biodiversity metrics are numerous, and care must be taken when using them. So, should one consider all these metrics to obtain the right information? If not, how should one choose? This paper aims to demonstrate the importance of understanding and selecting the appropriate diversity metrics to reach accurate conclusions. We simulated theoretical plant communities for which calculations of different biodiversity metrics were carried out to understand why and how to use them. We explored Richness, Evenness and Disparity components of biodiversity using both scales of diversity partitioning (i.e., alpha and beta diversity). In doing so, a decision tree is proposed to select diversity metrics according to user objectives. We also suggest an add-in term if alpha metrics are calculated with subsamples to better reflect biodiversity. Finally, we recommend that when dealing with ecosystem functioning or conservation concerns, species-dependent metrics should be used, as they reflect Disparity. However, there is a critical need to increase knowledge and data availability on species traits or phylogeny to be able to better analyze Disparity.