Interannual and spatial impacts of phenological transitions, growing season length, and spring and autumn temperatures on carbon sequestration: A North America flux data synthesis
- a Department of Geography, University of Toronto, 100 St. George St., Room 5047, Toronto, ON, Canada M5S 3G3
- b Natural Resources Canada, Canadian Forest Service-Pacific Forestry Centre, 506 West Burnside Road, Victoria, BC, Canada V8Z 1M5
- c Natural Resources Canada, Canadian Forest Service, Edmonton, Alberta, Canada T6H 3S5
- d Department of Geography, Trent University, Peterborough, Ontario, Canada K9J 7B8
- e Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, BC, Canada
- f Department of Geography, Indiana University, Bloomington, IN, USA
- g Department of Civil and Environmental Engineering and Geodetic Sci., Ohio State University, 417E Hitchcock Hall, 2070 Neil Ave, Columbus, OH 43210, USA
- h Department of Biology, Virginia Commonwealth University, Box 842012, 1000 W. Cary Street, Richmond, VA 23284-2012, USA
- i Great Plains Regional Center for Global Environmental Change, School of Natural Resources, University of Nebraska-Lincoln, Lincoln, NE, USA
- j Harvard School of Engineering and Applied Sciences 24 Oxford St. Cambridge, MA, 02138, USA
- Received 5 December 2011, Accepted 25 May 2012, Available online 2 June 2012
Abstract
Understanding feedbacks of ecosystem carbon sequestration to climate change is an urgent step in developing future ecosystem models. Using 187 site-years of flux data observed at 24 sites covering three plant functional types (i.e. evergreen forests (EF), deciduous forests (DF) and non-forest ecosystems (NF) (e.g., crop, grassland, wetland)) in North America, we present an analysis of both interannual and spatial relationships between annual net ecosystem production (NEP) and phenological indicators, including the flux-based carbon uptake period (CUP) and its transitions, degree-day-derived growing season length (GSL), and spring and autumn temperatures. Diverse responses were acquired between annul NEP and these indicators across PFTs. Forest ecosystems showed consistent patterns and sensitivities in the responses of annual NEP to CUP and its transitions both interannually and spatially. The NF ecosystems, on the contrary, exhibited different trends between interannual and spatial relationships. The impact of CUP onset on annual NEP in NF ecosystems was interannually negative but spatially positive. Generally, the GSL was observed to be a likely good indicator of annual NEP for all PFTs both interannually and spatially, although with relatively moderate correlations in NF sites. Both spring and autumn temperatures were positively correlated with annual NEP across sites while this potential was greatly reduced temporally with only negative impacts of autumn temperature on annual NEP in DF sites. Our analysis showed that DF ecosystems have the highest efficiency in accumulating NEP from warmer spring temperature and prolonged GSL, suggesting that future climate warming will favor deciduous species over evergreen species, and supporting the earlier observation that ecosystems with the greatest net carbon uptake have the longest GSL.
Highlights
► Responses of annual NEP to phenology show diverse temporal and spatial variations. ► Both CUP and its transitions have important implications for carbon sequestration. ► Future climate change would favor deciduous forests than evergreen forests. ► Autumn temperature may have opposite impact on annual carbon sequestration temporally and spatially.
Keywords
- spring temperature;
- growing season length;
- carbon;
- gross primary production;
- net ecosystem production;
- climate change
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