AME 64:267-273 (2011)  -  DOI: https://doi.org/10.3354/ame01527

ABSTRACT: Investigations of community composition often rely on metrics based on the abundance of taxonomic groups to estimate biodiversity. Although traditional measures of biodiversity, such as richness and evenness, can be used in a comparative fashion to evaluate differences among communities in both temporal and spatial contexts, these measures generally omit a phylogenetic perspective of the evolutionary diversity represented in a community. Using Fast UniFrac, we examined ­PhyloChip data from 9 microbial communities throughout the Great Salt Lake, Utah, USA, for changes in phylogenetic distance. We found a significant correlation (p < 0.001) between the decreased community phylogenetic distance and increased salt concentration. Despite significant differences in composition, communities in locations with a similar salt concentration had a similar phylogenetic distance. This trend was confirmed by analyzing the biodiversity of 89 published microbial communities classified as extreme (n = 20) and non-extreme (n = 69). Although we found no significant statistical difference in traditional diversity estimates, such as Chao1 and abundance-based coverage estimate (ACE), between environments, the phylogenetic distance within extreme communities is significantly lower than in non-extreme communities. A smaller phylogenetic distance within more extreme communities may imply evolutionary conservatism and specialization.

KEY WORDS: Biodiversity · Hypersaline · Extremophile · Phylogenetic distance · Ecology