What drives study-dependent differences in distance-decay relationships of microbial communities?
Clark, David; Underwood, Graham; McGenity, Terry; Dumbrell, Alex (2021), What drives study-dependent differences in distance-decay relationships of microbial communities?, Dryad, Dataset, https://doi.org/10.5061/dryad.7m0cfxpss
Aim: Ecological communities that exist closer together in space are generally more compositionally similar than those far apart, as defined by the distance-decay of similarity relationship. However, recent research has revealed substantial variability in the distance-decay relationships of microbial communities between studies of different taxonomic groups, ecosystems, spatial scales, as well as between those using different molecular methodologies (e.g. high-throughput sequencing versus molecular fingerprinting). Here, we test how these factors influence the strength of microbial distance-decay relationships, to draw generalisations about how microbial β-diversity scales with space.
Time period: Studies published between 2005-2019 (inclusive).
Major taxa studied: Bacteria, Archaea, and microbial Eukarya.
Methods: We conducted a meta-analysis of microbial distance-decay relationships, using the Mantel correlation coefficient as a measure of the strength of distance-decay relationships. Our final dataset consisted of 452 data points, varying in environmental/ecological context or methodological approaches, and used linear models to test the effects of each variable.
Results: Both ecological and methodological factors had significant impacts on the strength of microbial distance-decay relationships. Specifically, the strength of these relationships varied between environments and habitats, with soils showing significantly weaker distance-decay relationships than other habitats, whilst increasing spatial extents had no effect. Methodological factors such as sequencing depth were positively related to the strength of distance-decay relationships, and choice of dissimilarity metric was also important, with phylogenetic metrics generally giving weaker distance-decay relationships than binary or abundance-based indices.
Main conclusions: We conclude that widely studied microbial biogeographic patterns, such as the distance-decay relationship, vary by ecological context but are primarily distorted by methodological choices. Consequently, we suggest that by linking methodological approaches appropriately to the ecological context of a study, we can progress towards generalisable biogeographic relationships in microbial ecology.
Please see associated manuscript for all relevent details about dataset collection.
Missing values are coded as NA.
Natural Environment Research Council, Award: 471757