Data from: DNA metabarcoding illuminates dietary niche partitioning by African large herbivores

Niche partitioning facilitates species coexistence in a world of limited
resources, thereby enriching biodiversity. For decades, biologists have
sought to understand how diverse assemblages of large mammalian herbivores
(LMH) partition food resources. Several complementary mechanisms have been
identified, including differential consumption of grasses versus
nongrasses and spatiotemporal stratification in use of different parts of
the same plant. However, the extent to which LMH partition food-plant
species is largely unknown because comprehensive species-level
identification is prohibitively difficult with traditional methods. We
used DNA metabarcoding to quantify diet breadth, composition, and overlap
for seven abundant LMH species (six wild, one domestic) in semiarid
African savanna. These species ranged from almost-exclusive grazers to
almost-exclusive browsers: Grass consumption inferred from mean sequence
relative read abundance (RRA) ranged from >99% (plains zebra) to
<1% (dik-dik). Grass RRA was highly correlated with isotopic
estimates of % grass consumption, indicating that RRA conveys reliable
quantitative information about consumption. Dietary overlap was greatest
between species that were similar in body size and proportional grass
consumption. Nonetheless, diet composition differed between all
species—even pairs of grazers matched in size, digestive physiology, and
location—and dietary similarity was sometimes greater across grazing and
browsing guilds than within them. Such taxonomically fine-grained diet
partitioning suggests that coarse trophic categorizations may generate
misleading conclusions about competition and coexistence in LMH
assemblages, and that LMH diversity may be more tightly linked to plant
diversity than is currently recognized.