Evenness response to aridity gradients: Data required for Smith et al. 2022 Oecologia

These are the required data to do all analyses in Smith et al. 2022
in Oecologia using the assembled database
across gradients. Included are the richness, evenness, and site
level abiotic data. Paper abstract: We sought to understand the role
that water availability (expressed as an aridity index) plays in
determining regional and global patterns of richness and evenness,
and in turn how these water availability-diversity relationships may
result in different richness-evenness relationships at regional and
global scales. We examined relationships between water availability,
richness and evenness for eight grassy biomes spanning broad water
availability gradients on five continents. Our study found that
relationships between richness and water availability switched from
positive for drier (South Africa, Tibet and USA) vs. negative for
wetter (India) biomes, though were not significant for the remaining
biomes. In contrast, only the India biome showed a significant
relationship between water availability and evenness, which was
negative. Globally, the richness-water availability relationship was
hump-shaped, however, not significant for evenness. At the regional
scale, a positive richness-evenness relationship was found for
grassy biomes in India and Inner Mongolia, China. In contrast, this
relationship was weakly concave-up globally. These results suggest
that different, independent factors are determining patterns of
species richness and evenness in grassy biomes, resulting in
differing richness-evenness relationships at regional and global
scales. As a consequence, richness and evenness may respond very
differently across spatial gradients to anthropogenic changes, such
as climate change.