DOI: 10.1111/gcb.13775
论文题名: Measuring canopy loss and climatic thresholds from an extreme drought along a fivefold precipitation gradient across Texas
作者: Schwantes A.M. ; Swenson J.J. ; González-Roglich M. ; Johnson D.M. ; Domec J.-C. ; Jackson R.B.
刊名: Global Change Biology
ISSN: 13541013
出版年: 2017
语种: 英语
英文关键词: Change detection
; Climate change
; Disturbance
; Extreme event
; Forest die-off
; Random forests
; Tree mortality
; Vapor pressure deficit
英文摘要: Globally, trees are increasingly dying from extreme drought, a trend that is expected to increase with climate change. Loss of trees has significant ecological, biophysical, and biogeochemical consequences. In 2011, a record drought caused widespread tree mortality in Texas. Using remotely sensed imagery, we quantified canopy loss during and after the drought across the state at 30-m spatial resolution, from the eastern pine/hardwood forests to the western shrublands, a region that includes the boundaries of many species ranges. Canopy loss observations in ~200 multitemporal fine-scale orthophotos (1-m) were used to train coarser Landsat imagery (30-m) to create 30-m binary statewide canopy loss maps. We found that canopy loss occurred across all major ecoregions of Texas, with an average loss of 9.5%. The drought had the highest impact in post oak woodlands, pinyon-juniper shrublands and Ashe juniper woodlands. Focusing on a 100-km by ~1,000-km transect spanning the State's fivefold east-west precipitation gradient (~1,500 to ~300 mm), we compared spatially explicit 2011 climatic anomalies to our canopy loss maps. Much of the canopy loss occurred in areas that passed specific climatic thresholds: warm season anomalies in mean temperature (+1.6°C) and vapor pressure deficit (VPD, +0.66 kPa), annual percent deviation in precipitation (-38%), and 2011 difference between precipitation and potential evapotranspiration (-1,206 mm). Although similarly low precipitation occurred during the landmark 1950s drought, the VPD and temperature anomalies observed in 2011 were even greater. Furthermore, future climate data under the representative concentration pathway 8.5 trajectory project that average values will surpass the 2011 VPD anomaly during the 2070-2099 period and the temperature anomaly during the 2040-2099 period. Identifying vulnerable ecological systems to drought stress and climate thresholds associated with canopy loss will aid in predicting how forests will respond to a changing climate and how ecological landscapes will change in the near term. © 2017 John Wiley & Sons Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/61096
Appears in Collections: 影响、适应和脆弱性
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作者单位: Nicholas School of the Environment Duke University Durham, NC USA; Conservation International Arlington, VA USA; Department of Forest Rangeland and Fire Sciences University of Idaho Moscow, ID USA; Bordeaux Sciences Agro UMR INRA-ISPA 1391 Gradignan France; Department of Earth System Science Woods Institute for the Environment and Precourt Institute for Energy Stanford University Stanford, CA USA
Recommended Citation:
Schwantes A.M.,Swenson J.J.,González-Roglich M.,et al. Measuring canopy loss and climatic thresholds from an extreme drought along a fivefold precipitation gradient across Texas[J]. Global Change Biology,2017-01-01