Elevation gradient vs elevation replicates
The study of global biodiversity patterns has been a major topic of biological research since the age of exploration. The development of high throughput sequencing (HTS) methods has revolutionized the study of microbial biodiversity and finally made it possible to explore diversity patterns beyond macroscopic plants and animals. DNA extracted from environmental samples can be used to assess the diversity of selected or larger groups of microorganisms. However, as the soil environment is highly heterogeneous two samples collected in a same general habitat may yield quite contrasted communities as assessed by HTS. To quantify spatial heterogeneity and assess elevational diversity patterns of soil eukaryotic microbes we compared two sampling strategy: either taking five replicates at six elevational bands or taking a single sample at 16 different elevational bands along the same elevation gradients. The single sample strategy delivered congruent results compared to the replicate strategy for the estimation of elevational alpha diversity pattern. Community composition within same elevational band or among 100m elevation interval shows moderate degrees of heterogeneity (i.e low beta diversity). This implied that a single plot per elevation band will be sufficient to obtain a good estimate of diversity patterns along elevation gradients. Single sample strategy could also yield similar results when identifying the underlying mechanism in shaping beta diversity pattern along elevational gradient. This study demonstrated the effectiveness of single sample strategy in estimating diversity patterns along elevation gradients which is instructive for future environmental or even experimental studies.