Author(s)

Wenjun Chen¹, Paul Zorn², Lori White³, Ian Olthof¹, Yu Zhang¹, Robert Fraser¹, Sylvain Leblanc¹

¹Canada Centre for Remote Sensing, Natural Resources Canada, Ottawa, Canada.
²Parks Canada Agency, Gatineau, Canada.
³Wildlife Landscape Science Directorate, Environment Canada, Ottawa, Canada.

Given the short duration of growing season in the Arctic, a strong correlation between plant productivity and growing season length (GSL) is conventionally assumed. Will this assumption hold true under a warming climate? In this study, we addressed the question by investigating the relationship between net primary productivity of leaves (NPP_leaf) and GSL for various tundra ecosystems. We quantified NPP_leaf and GSL using long-term satellite data and field measurements. Our results indicated that the relationship was not significant (i.e., decoupled) for 44% to 64% of tundra classes in the southern Canadian Arctic, but significant for all classes in the northern Canadian Arctic. To better understand the causes of the decoupling, we further decomposed the relationship into two components: the correspondence of interannual variations and the agreement of long- term trends. We found that the longer the mean GSL for a tundra class, the poorer the correspondence between their interannual variations. Soil moisture limitation further decoupled the relationship by deteriorating the agreement of long-term trends. Consequently, the decoupling between NPP_leaf and GSL would be more likely to occur under a warming climate if the tundra class had a mean GSL > 116 (or 123) days with a dry (or moist) soil moisture regime.

Net Primary Productivity, Growing Season Length, Arctic Tundra, Decoupling, Remote Sensing, Soil Moisture Regime

Chen, W. , Zorn, P. , White, L. , Olthof, I. , Zhang, Y. , Fraser, R. and Leblanc, S. (2016) Decoupling between Plant Productivity and Growing Season Length under a Warming Climate in Canada’s Arctic. American Journal of Climate Change, 5, 334-359. doi: 10.4236/ajcc.2016.53026.