A mechanism of expansion: Arctic deciduous shrubs capitalize on warming-induced nutrient availability.

Case M Prager, Natalie T Boelman, Jan U H Eitel, Jess T Gersony, Heather E Greaves, Mary A Heskel, Troy S Magney, Duncan N L Menge, Shahid Naeem, Christa Shen, Lee A Vierling, Kevin L Griffin

Journal: Oecologia 2020;192(3):671-685

PMID: 32052180

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Abstract

Warming-induced nutrient enrichment in the Arctic may lead to shifts in leaf-level physiological properties and processes with potential consequences for plant community dynamics and ecosystem function. To explore the physiological responses of Arctic tundra vegetation to increasing nutrient availability, we examined how a set of leaf nutrient and physiological characteristics of eight plant species (representing four plant functional groups) respond to a gradient of experimental nitrogen (N) and phosphorus (P) enrichment. Specifically, we examined a set of chlorophyll fluorescence measures related to photosynthetic efficiency, performance and stress, and two leaf nutrient traits (leaf %C and %N), across an experimental nutrient gradient at the Arctic Long Term Ecological Research site, located in the northern foothills of the Brooks Range, Alaska. In addition, we explicitly assessed the direct relationships between chlorophyll fluorescence and leaf %N. We found significant differences in physiological and nutrient traits between species and plant functional groups, and we found that species within one functional group (deciduous shrubs) have significantly greater leaf %N at high levels of nutrient addition. In addition, we found positive, saturating relationships between leaf %N and chlorophyll fluorescence measures across all species. Our results highlight species-specific differences in leaf nutrient traits and physiology in this ecosystem. In particular, the effects of a gradient of nutrient enrichment were most prominent in deciduous plant species, the plant functional group known to be increasing in relative abundance with warming in this ecosystem.

Address: Department of Ecology, Evolution, and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, NY, 10027, USA. [email protected].; Rubenstein School of the Environment and Natural Resources, University of Vermont, 81 Carrigan Drive, Burlington, VT, 05405, USA. [email protected].; Department of Biology, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350, København K, Denmark. [email protected].; Department of Earth and Environmental Sciences, Columbia University, 1200 Amsterdam Avenue, New York, NY, 10027, USA.; Lamont-Doherty Earth Observatory, Columbia University, 61 Rte 9W, Palisades, NY, 10964, USA.; Geospatial Laboratory for Environmental Dynamics, Department of Natural Resources and Society, University of Idaho, 875 Perimeter Dr MS1142, Moscow, ID, 83844, USA.; McCall Outdoor Science School, University of Idaho, McCall, ID, 83638, USA.; Department of Ecology, Evolution, and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, NY, 10027, USA.; Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford St, Cambridge, MA, 02138, USA.; Institute of Arctic Biology, University of Alaska Fairbanks, 2140 Koyukuk Drive, Fairbanks, AK, 99775, USA.; Department of Biology, Macalester College, Olin-Rice Science Center, 1600 Grand Avenue, Saint Paul, MN, 55105, USA.; Department of Plant Sciences, University of California, Davis, One Shields Avenue, Davis, CA, 95616, USA.

DOI: 10.1007/s00442-019-04586-8

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https://dx.doi.org/10.1007/s00442-019-04586-8

MeSH Terms: Alaska, Arctic Regions, Ecosystem, Nutrients, Tundra