title: Aspect has a greater impact on alpine soil bacterial community structure than elevation.
abstract: Gradients in environmental conditions, including climate factors and resource availability, occur along mountain inclines, providing a 'natural laboratory' to explore their combined impacts on microbial distributions. Conflicting spatial patterns observed across elevation gradients in soil bacterial community structure suggest that they are driven by various interacting factors at different spatial scales. Here, we investigated the relative impacts of non-resource (e.g. soil temperature, pH) and resource conditions (e.g. soil carbon and nitrogen) on the biogeography of soil bacterial communities across broad (i.e. along a 1500 m mountain elevation gradient) and fine sampling scales (i.e. along sunny and shady aspects of a mountain ridge). Our analysis of 16S rRNA gene data confirmed that when sampling across distances of < 1000 m, bacterial community composition was more closely related to the aspect of a site than its elevation. However, despite large differences in climate and resource-availability factors across elevation- and aspect-related gradients, bacterial community composition and richness were most strongly correlated with soil pH. These findings highlight the need to incorporate knowledge of multiple factors, including site aspect and soil pH for the appropriate use of elevation gradients as a proxy to explore the impacts of climate change on microbial community composition.
authors.affiliation: School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1010, New Zealand.
authors.forename: Jieyun
authors.initials: J
authors.lastname: Wu
authors.affiliation: Biodiversity and Conservation Group, Landcare Research Ltd., Private Bag 1930, Dunedin 9054, New Zealand.
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Anderson
authors.affiliation: School of Science, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand.
authors.forename: Hannah L
authors.initials: HL
authors.lastname: Buckley
authors.affiliation: School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1010, New Zealand.
authors.forename: Gillian
authors.initials: G
authors.lastname: Lewis
authors.affiliation: School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1010, New Zealand.
authors.forename: Gavin
authors.initials: G
authors.lastname: Lear
mesh_terms: D001419:Bacteria / Q000235:genetics; D002980:Climate; D057231:Climate Change; D009584:Nitrogen; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D013472:Sunlight
chemical_list: D012336:RNA, Ribosomal, 16S; D012987:Soil; D009584:Nitrogen
keywords: 16S rRNA; micro-climate; next-generation sequencing; pH gradient; soil microbiology