Peter Wagner 0000-0002-9083-9787
S. Kathleen Lyons 0000-0001-5112-2508
Date of this Version
American Naturalist 2018. Vol. 192, pp. E120–E138.
Biological systems provide examples of differential success among taxa, from ecosystems with a few dominant species (ecological success) to clades that possess far more species than sister clades (macroevolutionary success). Macroecological success, the occupation by a species or clade of an unusually high number of areas, has received less attention. If macroecological success reflects heritable traits, then successful species should be related. Genera composed of species possessing those traits should occupy more areas than genera with comparable species richness that lack such traits. Alternatively, if macroecological success reflects autapomorphic traits, then generic occupancy should be a by-product of species richness among genera and occupancy of constituent species. We test this using Phanerozoic marine invertebrates. Although temporal patterns of species and generic occupancy are strongly correlated, inequality in generic occupancy typically is greater than expected. Genus-level patterns cannot be explained solely with species-level patterns. Within individual intervals, deviations between the observed and expected generic occupancy correlate with the number of lithological units (stratigraphic formations), particularly after controlling for geographic range and species richness. However, elevated generic occupancy is unrelated to or negatively associated with either generic geographic ranges or within-genus species richness. Our results suggest that shared traits among congeneric species encourage shortterm macroecological success without generating short-term macroevolutionary success. A broad niche may confer high occupancy but does not necessarily promote speciation.
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