Accounting for landscape heterogeneity improves spatial predictions of tree vulnerability to drought

Amanda M. Schwantes, Anthony J. Parolari, Jennifer J. Swenson, Daniel M. Johnson, Jean Christophe Domec, Robert B. Jackson, Norman Pelak, Amilcare Michele M. Porporato

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

As climate change continues, forest vulnerability to droughts and heatwaves is increasing, but vulnerability varies regionally and locally through landscape position. Also, most models used in forecasting forest responses to heat and drought do not incorporate relevant spatial processes. In order to improve spatial predictions of tree vulnerability, we employed a nonlinear stochastic model of soil moisture dynamics accounting for landscape differences in aspect, topography and soils. Across a watershed in central Texas we modeled dynamic water stress for a dominant tree species, Juniperus ashei, and projected future dynamic water stress through the 21st century. Modeled dynamic water stress tracked spatial patterns of remotely sensed drought-induced canopy loss. Accuracy in predicting drought-impacted stands increased from 60%, accounting for spatially variable soil conditions, to 72% when also including lateral redistribution of water and radiation/temperature effects attributable to aspect. Our analysis also suggests that dynamic water stress will increase through the 21st century, with trees persisting at only selected microsites. Favorable microsites/refugia may exist across a landscape where trees can persist; however, if future droughts are too severe, the buffering capacity of an heterogeneous landscape could be overwhelmed. Incorporating spatial data will improve projections of future tree water stress and identification of potential resilient refugia.

Original languageEnglish (US)
Pages (from-to)132-146
Number of pages15
JournalNew Phytologist
Volume220
Issue number1
DOIs
StatePublished - Oct 2018

All Science Journal Classification (ASJC) codes

  • Physiology
  • Plant Science

Keywords

  • climate change
  • drought-induced tree mortality
  • heat load
  • landscape diversity
  • soil moisture
  • stochastic processes
  • topographic convergence
  • water stress

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  • Cite this

    Schwantes, A. M., Parolari, A. J., Swenson, J. J., Johnson, D. M., Domec, J. C., Jackson, R. B., Pelak, N., & Porporato, A. M. M. (2018). Accounting for landscape heterogeneity improves spatial predictions of tree vulnerability to drought. New Phytologist, 220(1), 132-146. https://doi.org/10.1111/nph.15274