Soils beneath different arctic shrubs have contrasting responses to a natural gradient in temperature

Journal Article · Wed Jun 13 00:00:00 EDT 2018 · Ecosphere

DOI:https://doi.org/10.1002/ecs2.2290· OSTI ID:1454375

Zhao, Qiong ^[1]; Sundqvist, Maja K. ^[2]; Newman, Gregory S. ^[3]; Classen, Aimée T. ^[4]

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1. CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang 110016 China, The Center for Macroecology, Evolution and Climate, The Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø Denmark
2. The Center for Macroecology, Evolution and Climate, The Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø Denmark, Department of Ecology and Environmental Science, Umeå University, 901 87 Umeå Sweden
3. The Center for Macroecology, Evolution and Climate, The Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø Denmark, Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington Vermont 05405 USA
4. The Center for Macroecology, Evolution and Climate, The Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø Denmark, Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington Vermont 05405 USA, The Gund Institute for Environment, University of Vermont, Burlington Vermont 05405 USA

Shrubs commonly form islands of fertility and are expanding their distribution and dominance in the arctic due to climate change, yet how soil properties may be influenced when different species of shrubs expand under warmer climates remains less explored. Important plant traits, such as their associated root community, are linked to functionally different and dominant shrub species in the arctic and these traits likely shape biogeochemical cycling in areas of shrub expansion. Using an elevational gradient as a proxy for warming, we explored how biochemical processes beneath two important arctic shrubs varied under warmer (low elevation) and cooler (high elevation) climates. Interestingly, the influence of elevation on biogeochemistry varied between the two shrubs. At the low elevation, Betula nana L., an ectomycorrhizal shrub, had high carbon (C) degrading enzyme activities, and relatively low potential net nitrogen (N) mineralization rates. Conversely, ,Empetrum nigrum ssp. hermaphroditum Hagerup, an ericoid mycorrhizal dwarf-shrub, had higher enzyme activities and net N immobilization rates at the higher eleva-tion. Further, E. nigrum ssp. hermpahroditum appeared to have a more closed C and nutrient cycle than B. nana—enzymes degrading C, N, and phosphorus were tightly correlated with each other and with total C and ammonium concentrations in the humus beneath E. nigrum ssp. hermaphroditum, but not beneath B. nana. Thus, our results suggest differences in the warming responses of C and N cycling beneath shrub species across an arctic tundra landscape.

• Research Organization: Univ. of Tennessee, Knoxville, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER)
• Grant/Contract Number: SC0010562
• OSTI ID: 1454375
• Alternate ID(s): OSTI ID: 1458605; OSTI ID: 1501395
• Journal Information: Ecosphere, Journal Name: Ecosphere Vol. 9 Journal Issue: 6; ISSN 2150-8925
• Publisher: Ecological Society of America
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES