TY - JOUR
T1 - Spatial and temporal variations in ecosystem response to monsoon precipitation variability in southwestern North America
AU - Forzieri, Giovanni
AU - Feyen, Luc
AU - Cescatti, Alessandro
AU - Vivoni, Enrique
N1 - Funding Information:
We thank B. Yue, A. Ferrara, N. Cappelluti and E. Komatsu for useful discussions. KH was supported by the European Unions Seventh Framework Programme (FP7-PEOPLE-2013-IFF) under grant agreement number 628319-CIBorigins, and byNASAHeadquarters under the NESSF Program Grant - NNX11AO05H. MR acknowledges support from NSF CDI-typeII grant CMMI1125285 and the Theoretical and Computational Astrophysics Network (TCAN) grant AST1333514. AK acknowledges NASA's support for the Euclid LIBRAE project NNN12AA01C. VB was supported by NSF grant AST-1413501.
Publisher Copyright:
© 2014. The Authors.
PY - 2014/10/1
Y1 - 2014/10/1
N2 - Due to its marked vegetation phenology and precipitation gradients, the North American Monsoon Region (NAMR) is a useful domain for studying ecosystem responses to climate variability and change. To this end, we analyze long-term dynamics (1982-2004) in monsoon precipitation (Pr), time-integrated Normalized Difference Vegetation Index (TINDVI) used as proxy of net primary productivity, and rain-use efficiency (RUE). The analysis focuses on six ecoregions, spanning from desert environments to tropical dry forests, to investigate (1) how net primary productivity and rain-use efficiency vary along a precipitation gradient, (2) if interannual variability in net primary productivity is linked to the interannual variability in precipitation, and (3) if there is evidence of a long-term signal imposed on the interannual variability in rain-use efficiency. Variations in TINDVI and RUE with Pr along the NAMR precipitation gradient differ among ecoregions exhibiting intensive or extensive water use strategies. We explain the nonlinear behaviors along the precipitation gradient as resulting from different physiological responses to climatological means and the impact of topographic effects. Statistical analysis indicates that the interannual variability in vegetation response is significantly related to the interannual variability in Pr, but their correlation declines with time. A long-term positive signal in RUE imposed on its interannual variability is identified and results from a constant TINDVI under negative long-term trends of Pr. This important finding suggests the combined long-term effects of ecosystem acclimation to reduced water availability and increasing CO2 concentration across the varied ecosystems of the North American Monsoon Region.
AB - Due to its marked vegetation phenology and precipitation gradients, the North American Monsoon Region (NAMR) is a useful domain for studying ecosystem responses to climate variability and change. To this end, we analyze long-term dynamics (1982-2004) in monsoon precipitation (Pr), time-integrated Normalized Difference Vegetation Index (TINDVI) used as proxy of net primary productivity, and rain-use efficiency (RUE). The analysis focuses on six ecoregions, spanning from desert environments to tropical dry forests, to investigate (1) how net primary productivity and rain-use efficiency vary along a precipitation gradient, (2) if interannual variability in net primary productivity is linked to the interannual variability in precipitation, and (3) if there is evidence of a long-term signal imposed on the interannual variability in rain-use efficiency. Variations in TINDVI and RUE with Pr along the NAMR precipitation gradient differ among ecoregions exhibiting intensive or extensive water use strategies. We explain the nonlinear behaviors along the precipitation gradient as resulting from different physiological responses to climatological means and the impact of topographic effects. Statistical analysis indicates that the interannual variability in vegetation response is significantly related to the interannual variability in Pr, but their correlation declines with time. A long-term positive signal in RUE imposed on its interannual variability is identified and results from a constant TINDVI under negative long-term trends of Pr. This important finding suggests the combined long-term effects of ecosystem acclimation to reduced water availability and increasing CO2 concentration across the varied ecosystems of the North American Monsoon Region.
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U2 - 10.1002/2014JG002710
DO - 10.1002/2014JG002710
M3 - Article
AN - SCOPUS:84924943355
SN - 2169-8953
VL - 119
SP - 1999
EP - 2017
JO - Journal of Geophysical Research: Biogeosciences
JF - Journal of Geophysical Research: Biogeosciences
IS - 10
ER -