DOI: 10.5061/dryad.pk71s98
title: Data from: Ant diversity in Neotropical savannas: hierarchical processes acting at multiple spatial scales

description: 1. Understanding what creates and maintains macroscale biodiversity
 gradients is a central focus of ecological and evolutionary research.
 Spatial patterns in diversity are driven by a hierarchy of factors
 operating at multiple scales. Historical and climatic factors drive
 large-scale patterns of diversity by affecting the size of regional
 species pools, while habitat heterogeneity or microhabitat characteristics
 further influence species coexistence at small scales. 2. We tested the
 degree to which the species-energy, historical factors, habitat
 heterogeneity and local environment hypotheses explain observed patterns
 of ant diversity across hierarchical spatial scales. 3. We sampled
 ground-dwelling ants at 29 sites within a Neotropical savanna region, the
 Brazilian Cerrado. We measured species density – an abundance-dependent
 diversity metric – and rarefied species richness – an
 abundance-independent metric – at spatial scales with varying grain sizes.
 For each hypothesis, two correlates were used to predict ant diversity
 patterns: i) species-energy: rainfall and productivity; ii) historical
 factors: historical variation in rainfall and refugial areas; iii) habitat
 heterogeneity: heterogeneity in greenness and diversity of land cover; iv)
 local factors: contents of sand and coarse fragments in the soil. 4. Ant
 diversity patterns correlated to net primary productivity and to the
 proportion of coarse fragments in the soil, corroborating the
 species-energy and local environment hypotheses, respectively. Soil
 negatively influenced species density, but not rarefied species richness,
 which was positively influenced by productivity. We found scale
 dependencies in the effects of soil/productivity on species density;
 productivity best predicted species density patterns at large scales,
 since sampling completeness offset the abundance-driven effects of soil.
 5. Considering abundance differences may help to discern the mechanisms
 underlying the relationship between macroscale diversity patterns and its
 ecological drivers. Plant productivity affected ant diversity
 independently of abundance, possibly by limiting the size of regional
 species pools. On the other hand, soil properties had an
 abundance-dependent effect on ant diversity, indicating a sampling
 mechanism. Our findings are consistent with predictions of the
 hierarchical theory of diversity. Large-scale patterns of productivity
 limit regional diversity, an effect that cascades down to finer spatial
 scales, where soil properties influence the number of coexisting species.
description: Ant diversity in a
 Neotropical savanna_DRYADZ-scores of predictor
 and response variables in 29 sites analyzed in this study. Codes and
 geographic locations of sites are also provided. SD: species density; RSR:
 rarefied species richness; RAIN: mean annual rainfall; NPP: net primary
 productivity; DLC: diversity of land cover classes; HET: heterogeneity in
 greenness; REF: refugial areas; HDR: historical difference in rainfall;
 FRAG: proportion of coarse rock fragments in the soil; SAND: proportion of
 sand in the soil.