DOI: 10.5061/dryad.cnp5hqc46
title: Disentangling the effects of latitudinal and elevational gradients on bee, wasp, and ant diversity in an ancient Neotropical mountain range

description: Aim: Ancient tropical mountains are megadiverse, yet little is known about
 the distribution of their species. We aimed to disentangle the effects of
 latitudinal and elevational gradients on the distribution of species of
 Aculeata and to understand the effects of climatic variables across
 different spatial scales of diversity (α, γ, and β-diversity). Location:
 Campo rupestre in the Espinhaço Mountain Range, Southeast Brazil. Taxon:
 Bees, wasps, and ants (Aculeata: Hymenoptera) Methods: We used a unique
 dataset built from sampling species of Aculeata at 24 study sites across
 12 mountains, covering 1200 km from south to north and an elevational
 range of 1000 to 2000 m. We explored the elevational and latitudinal
 patterns of α (site), γ (mountain), and β-diversity among samples at each
 location (β Local). We also tested the effect of elevational range on
 β-diversity in each mountain (β Mountain) and, on a larger scale (β
 Regional), if β-diversity is influenced by geographical and environmental
 distances. Finally, we tested whether climatic variables underpin the
 observed patterns. Results: Latitude had no effect on diversity. We found
 a decrease in both site and mountain diversity and, only for bees, β Local
 increased with elevation. Climatic variables (temperature, wind, and
 precipitation) and their interactions were important drivers of diversity,
 with temperature being the most important. Finally, β Mountain increased
 with mountain elevation range, and β Regional increased with the
 geographical and environmental distances. Main conclusions: Our results
 showed that variation in species richness and composition across mountains
 is strongly associated with elevational gradient, which showed stronger
 climatic variation than latitudinal gradient. Therefore, despite having
 narrow elevational ranges, the biogeographical effects of tropical
 mountains drive high diversity. Facing global climate changes, this
 limited elevational gradient may limit species range shifts, leading to
 severe biodiversity losses.
description: Our study was conducted along a latitudinal gradient ranging from
 12ºS to 20ºS and elevation ranging from 1000 to 2072 m in a standardized
 sampling, considering a single ecosystem: the campo rupestre. It is a
 neotropical grassland mosaic in association with azonal vegetation
 complexes on rocky outcrops, formally classified as old, climate-buffered,
 and infertile landscapes (OCBILs). The campo rupestre distribution is
 manly associated with Espinhaço Mountain Range surfaces (above 900 m, a
 mountainous formation that extends for more than 1200 km north-south, with
 east-west width rarely exceeding 100 km. We rely on a unique dataset of
 Aculeata sampled in 12 mountains, covering 1200 km from south to north
 (nine degrees of latitude) and an elevational range from 1000 m up to 2000
 m. In each locality (n=12 mountains) we selected two sample sites at
 different elevations, always in campo rupestre ecosystem, to test the
 elevation effect: one at the mountain base (Lower site: 1100 m) and
 another one near the mountain summit (Upper site: ranging from 1300 to
 2000 m). We installed five trap sets 200 m apart from each other at each
 elevation mountain site, totalling 120 trap sets. Each set was composed by
 one malaise trap (to capture flying Acuelata; exposed in the field for 14
  hours), four Moericke traps (yellow pan traps to capture pollinators; 48
 hours each), and four pitfall traps (to capture ground Aculeata; 48 hours
 each) totalling 17,280 malaise trap hours, 23,040 Moericke, and 23,040
 pitfall trap hours within the 120 trap sets. Each locality was sampled
 once, during the rainy season (November to February between 2013 and
 2016).