Practice question

Alpha diversity is defined within a single local habitat or community. Among the scale descriptions given, “single habitat” is therefore the appropriate unit for an alpha-diversity measurement. An ecosystem may contain several habitat types, multiple communities explicitly span a broader comparison, and a whole region corresponds to gamma diversity. The wording “greater alpha diversity” is imprecise because a spatial category alone does not guarantee a larger numerical value; actual richness and abundance data are needed to decide which specific habitat is most diverse. The scientifically valid point is that alpha is assessed at the single-habitat scale, not that every single habitat has more species than every region. Beta diversity describes change among local habitats, while gamma diversity pools them across the region. A local community may have high alpha diversity because it contains many evenly represented species, yet regional gamma will ordinarily be at least as large in richness terms because it includes the union of local species. The keyed choice should thus be understood as identifying the scale of alpha diversity, with the comparative adjective treated as a flaw in the stem rather than a literal cross-scale ranking.