title: Niche and metabolic principles explain patterns of diversity and distribution: theory and a case study with soil bacterial communities.
abstract: The causes of biodiversity patterns are controversial and elusive due to complex environmental variation, covarying changes in communities, and lack of baseline and null theories to differentiate straightforward causes from more complex mechanisms. To address these limitations, we developed general diversity theory integrating metabolic principles with niche-based community assembly. We evaluated this theory by investigating patterns in the diversity and distribution of soil bacteria taxa across four orders of magnitude variation in spatial scale on an Antarctic mountainside in low complexity, highly oligotrophic soils. Our theory predicts that lower temperatures should reduce taxon niche widths along environmental gradients due to decreasing growth rates, and the changing niche widths should lead to contrasting α- and β-diversity patterns. In accord with the predictions, α-diversity, niche widths and occupancies decreased while β-diversity increased with increasing elevation and decreasing temperature. The theory also successfully predicts a hump-shaped relationship between α-diversity and pH and a negative relationship between α-diversity and salinity. Thus, a few simple principles explained systematic microbial diversity variation along multiple gradients. Such general theory can be used to disentangle baseline effects from more complex effects of temperature and other variables on biodiversity patterns in a variety of ecosystems and organisms.
authors.affiliation: School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA School of Life Sciences, Arizona State University, Tempe, AZ, USA jordan.okie@asu.edu.
authors.forename: Jordan G
authors.initials: JG
authors.lastname: Okie
authors.affiliation: Department of Biology, University of New Mexico, Albuquerque, NM, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Van Horn
authors.affiliation: Center for Theoretical Study, Charles University, Prague, Czech Republic Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic Department of Biological Sciences, Virginia Technological Institute, Blacksburg, VA, USA.
authors.forename: David
authors.initials: D
authors.lastname: Storch
authors.affiliation: Department of Biological Sciences, Virginia Technological Institute, Blacksburg, VA, USA.
authors.forename: John E
authors.initials: JE
authors.lastname: Barrett
authors.affiliation: Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO, USA.
authors.forename: Michael N
authors.initials: MN
authors.lastname: Gooseff
authors.affiliation: Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic.
authors.forename: Lenka
authors.initials: L
authors.lastname: Kopsova
authors.affiliation: Department of Biology, University of New Mexico, Albuquerque, NM, USA.
authors.forename: Cristina D
authors.initials: CD
authors.lastname: Takacs-Vesbach
mesh_terms: D000864:Antarctic Regions; D001419:Bacteria / Q000378:metabolism*; D017753:Ecosystem; D064307:Microbiota; D012988:Soil Microbiology
keywords: elevational gradient; macroecology; metabolic theory; microbial biogeography; microbial communities; species richness patterns