Conclusions
Our results are consistent with the expectations of the neutral theory of biodiversity (Hubbell, 2001) and with the idea that global patterns of hyperdiverse tropical mountains reflect the differentiation of small isolated populations combined with their long-term persistence (Bray & Bocak, 2016; Rahbek et al., 2019a). Complementing studies that focus on population isolation among different mountains, here we found that the composition of arthropods communities shows strong turnover within a sky-island and a limited geographic scale (<20 km). We also found that distance and elevation drive biodiversity structure from haplotypes to lineages levels. In groups of low dispersal ability (Collembola), this pattern holds even at a very fine spatial scale (<2 km). Therefore, our results support a general model where neutral dynamics and dispersal limitations act as a source of local-scale diversity within tropical mountains.