title: Moss Mediates the Influence of Shrub Species on Soil Properties and Processes in Alpine Tundra.
abstract: In tundra ecosystems, bryophytes influence soil processes directly and indirectly through interactions with overstory shrub species. We experimentally manipulated moss cover and measured seasonal soil properties and processes under two species of deciduous shrubs with contrasting canopy structures, Salix planifolia pulchra and Betula glandulosa-nana complex. Soil properties (seasonal temperature, moisture and C:N ratios) and processes (seasonal litter decomposition and soil respiration) were measured over twelve months. Shrub species identity had the largest influence on summer soil temperatures and soil respiration rates, which were higher under Salix canopies. Mosses were associated with lower soil moisture irrespective of shrub identity, but modulated the effects of shrubs on winter soil temperatures and soil C:N ratios so that moss cover reduced differences in soil winter temperatures between shrub species and reduced C:N ratios under Betula but not under Salix canopies. Our results suggest a central role of mosses in mediating soil properties and processes, with their influence depending on shrub species identity. Such species-dependent effects need to be accounted for when forecasting vegetation dynamics under ongoing environmental changes.
authors.affiliation: Institute of Ecology and Earth Sciences, Department of Botany, University of Tartu, Lai 40, Tartu, 51005, Estonia.|Pyrenean Institute of Ecology (CSIC), Avda. Nuestra Señora de la Victoria s/n, 22700, Jaca, Spain.|Department of Biological Sciences, University of Alberta, Biological Sciences Building, T6G 2E9, Edmonton, Canada.
authors.forename: C Guillermo
authors.identifier: http://orcid.org/0000-0002-7288-2271
authors.initials: CG
authors.lastname: Bueno
authors.affiliation: Department of Biological Sciences, University of Alberta, Biological Sciences Building, T6G 2E9, Edmonton, Canada.
authors.forename: Scott N
authors.initials: SN
authors.lastname: Williamson
authors.affiliation: Department of Biological Sciences, University of Alberta, Biological Sciences Building, T6G 2E9, Edmonton, Canada.|Department of Life and Environmental Sciences, University of Iceland, Sturlugata 7, 101, Reykjavik, Iceland.
authors.forename: Isabel C
authors.initials: IC
authors.lastname: Barrio
authors.affiliation: Department of Life and Environmental Sciences, University of Iceland, Sturlugata 7, 101, Reykjavik, Iceland.|Soil Conservation Service of Iceland, Gunnarsholt, 851, Hella, Iceland.
authors.forename: Ágústa
authors.initials: Á
authors.lastname: Helgadóttir
authors.affiliation: Department of Biological Sciences, University of Alberta, Biological Sciences Building, T6G 2E9, Edmonton, Canada.
authors.forename: David S
authors.initials: DS
authors.lastname: HiK
mesh_terms: D044002:Bryophyta; D055669:Ecological and Environmental Phenomena; D012987:Soil / Q000737:chemistry*; D013696:Temperature; D065929:Tundra
chemical_list: D012987:Soil