title: Determinants of bacterial communities in Canadian agroforestry systems.
abstract: Land-use change is one of the most important factors influencing soil microbial communities, which play a pivotal role in most biogeochemical and ecological processes. Using agroforestry systems as a model, this study examined the effects of land uses and edaphic properties on bacterial communities in three agroforestry types covering a 270 km soil-climate gradient in Alberta, Canada. Our results demonstrate that land-use patterns exert stronger effects on soil bacterial communities than soil zones in these agroforestry systems. Plots with trees in agroforestry systems promoted greater bacterial abundance and to some extent species richness, which was associated with more nutrient-rich soil resources. While Acidobacteria, Actinobacteria and Alphaproteobacteria were the dominant bacterial phyla and subphyla across land uses, Arthrobacter, Acidobacteria_Gp16, Burkholderia, Rhodanobacter and Rhizobium were the keystone taxa in these agroforestry systems. Soil pH and carbon contents emerged as the major determinants of bacterial community characteristics. We found non-random co-occurrence and modular patterns of soil bacterial communities, and these patterns were controlled by edaphic factors and not their taxonomy. Overall, this study highlights the drivers and co-occurrence patterns of soil microbial communities in agroforestry systems.
authors.affiliation: Department of Renewable Resources, University of Alberta, 442 Earth Science Building, Edmonton, Alberta, T6G 2E3, Canada.|CSIRO Agriculture Flagship, Crace, ACT, 2911, Australia.
authors.forename: Samiran
authors.initials: S
authors.lastname: Banerjee
authors.affiliation: Department of Renewable Resources, University of Alberta, 442 Earth Science Building, Edmonton, Alberta, T6G 2E3, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Baah-Acheamfour
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, 410 Agriculture/Forestry Centre, Edmonton, Alberta, T6G 2H1, Canada.
authors.forename: Cameron N
authors.initials: CN
authors.lastname: Carlyle
authors.affiliation: CSIRO Agriculture Flagship, Crace, ACT, 2911, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Bissett
authors.affiliation: CSIRO Agriculture Flagship, Crace, ACT, 2911, Australia.
authors.forename: Alan E
authors.initials: AE
authors.lastname: Richardson
authors.affiliation: Department of Renewable Resources, University of Alberta, 442 Earth Science Building, Edmonton, Alberta, T6G 2E3, Canada.
authors.forename: Tariq
authors.initials: T
authors.lastname: Siddique
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, 410 Agriculture/Forestry Centre, Edmonton, Alberta, T6G 2H1, Canada.
authors.forename: Edward W
authors.initials: EW
authors.lastname: Bork
authors.affiliation: Department of Renewable Resources, University of Alberta, 442 Earth Science Building, Edmonton, Alberta, T6G 2E3, Canada.
authors.forename: Scott X
authors.initials: SX
authors.lastname: Chang
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D002170:Canada; D002244:Carbon / Q000032:analysis; D002980:Climate; D065928:Forests; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D014197:Trees / Q000382:microbiology*
chemical_list: D012987:Soil; D002244:Carbon