Alpha diversity, beta diversity and relative abundance
Alpha diversity summarises diversity within a sample, beta diversity compares samples, and relative abundance describes proportions rather than absolute microbial quantity.
01
One diversity number is not the ecosystem
Different alpha-diversity indices weight richness and evenness differently. State the index and avoid comparing unlike measures.
02
Ordination shows patterns
PCoA and related views display distances derived from a selected metric. Apparent separation should be tested and checked for confounding.
03
Composition constrains interpretation
An increase in one relative proportion can be caused by a decrease elsewhere. Absolute abundance requires additional measurement.
