Leaf phenology paradox: Why warming matters most where it is already warm

REMOTE SENSING OF ENVIRONMENT

卷:209

Article

Seyednasrollah, Bijan^1,2,3  Swenson, Jennifer J.²  Domec, Jean-Christophe^2,4  Clark, James S.^2,5 

[1] Harvard Univ, Dept Organism & Evolutionary Biol, Cambridge, MA 02138 USA

[2] Duke Univ, Nicholas Sch Environm, Durham, NC 27708 USA

[3] No Arizona Univ, Sch Informat Comp & Cyber Syst, Flagstaff, AZ 86001 USA

[4] Bordeaux Sci Agro, UMR INRA ISPA 1391, F-33175 Gradignan, France

[5] Duke Univ, Dept Stat Sci, Durham, NC 27708 USA

关键词: Multispectral;    Daily Vegetation Index;    NDVI;    EVI;    MODIS;    Phenology;    Forest;    Green-up;    Bayesian;    Hierarchical modeling;    Spring;    Climate change;    Warming;    Land surface temperature;    Southeastern US;   

DOI  :  10.1016/j.rse.2018.02.059

来源: Elsevier

【 摘 要 】

Interactions between climate and ecosystem properties that control phenological responses to climate warming and drought are poorly understood. To determine contributions from these interactions, we used space-borne remotely sensed vegetation indices to monitor leaf development across climate gradients and ecoregions in the southeastern United States. We quantified how air temperature, drought severity, and canopy thermal stress contribute to changes in leaf flushing from mountainous to coastal plain regions by developing a hierarchical state-space Bayesian model. We synthesized daily field climate data with daily vegetation indices and canopy surface temperature during spring green-up season at 59 sites in the southeastern United States between 2001 and 2012. Our results demonstrated strong interaction effects between ecosystem properties and climate variables across ecoregions. We found spring green-up is faster in the mountains, while coastal forests express a larger sensitivity to inter-annual temperature anomalies. Despite our detection of a decreasing trend in sensitivity to warming with temperature in all regions, we identified an ecosystem interaction: Deciduous dominated forests are less sensitive to warming than are those with fewer deciduous trees, likely due to the continuous presence of leaves in evergreen species throughout the season. Mountainous forest green-up is more susceptible to intensifying drought and moisture deficit, while coastal areas are relatively resilient. We found that with increasing canopy thermal stress, defined as canopy-air temperature difference, leaf development slows following dry years, and accelerates following wet years.

【 授权许可】

Free