GLOSSARY

Alpha Diversity describes diversity within one defined sample, not differences between samples.

Alpha diversity concerns within-sample variation; beta diversity compares samples. Shannon and different Simpson forms weight richness and abundance differently, so specify the Simpson version. Operational taxonomic units come from clustering and amplicon variants from sequence inference; neither necessarily equals a biological species. Method, depth and index definition are needed for comparisons rather than a simple health ranking from one value or an assumed universal favorable direction.

Richness counts detected types, while evenness describes their abundance distribution; diversity may reflect both. Higher is not universally better at every site or in every condition. Sampling and sequencing depth affect results. An athlete's diversity value without symptoms, diet and method neither certifies health nor specifies a supplement or workout. Compare like methods and avoid treating a research index as a stand-alone clinical target.

Relative abundance is a share of the measured total, not an absolute count. A larger share may reflect declines elsewhere rather than growth of that organism. Extraction and analysis also influence estimates. Interpret before-and-after diet percentages with these constraints and the wider community. A colorful chart alone does not demonstrate causality, establish an ideal population size or justify trying to eliminate every low-abundance organism.