Decoupling between Plant Productivity and Growing Season Length under a Warming Climate in Canada’s Arctic  

作　　者：Wenjun Chen Paul Zorn Lori White Ian Olthof Yu Zhang Robert Fraser Sylvain Leblanc Wenjun Chen;Paul Zorn;Lori White;Ian Olthof;Yu Zhang;Robert Fraser;Sylvain Leblanc(Canada Centre for Remote Sensing, Natural Resources Canada, Ottawa, Canada;Parks Canada Agency, Gatineau, Canada;Wildlife Landscape Science Directorate, Environment Canada, Ottawa, Canada)

机构地区：[1]Canada Centre for Remote Sensing, Natural Resources Canada, Ottawa, Canada [2]Parks Canada Agency, Gatineau, Canada [3]Wildlife Landscape Science Directorate, Environment Canada, Ottawa, Canada

出　　处：《American Journal of Climate Change》2016年第3期334-359,共17页美国气候变化期刊（英文）

摘　　要：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.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.

关 键 词：Net Primary Productivity Growing Season Length Arctic Tundra DECOUPLING Remote Sensing Soil Moisture Regime 

分 类 号：G89[文化科学—体育学]