Variation in the resilience of cloud forest vascular epiphytes to severe drought

Sybil G. Gotsch, Todd E. Dawson, Danel Draguljić

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

Epiphytes are common in tropical montane cloud forests (TMCFs) and play many important ecological roles, but the degree to which these unique plants will be affected by changes in climate is unknown. We investigated the drought responses of three vascular epiphyte communities bracketing the cloud base during a severe, El Niño-impacted dry season. Epiphytes were instrumented with sap flow probes in each site. Leaf water potential and pressure–volume curve parameters were also measured before and during the drought. We monitored the canopy microclimate in each site to determine the drivers of sap velocity across the sites. All plants greatly reduced their water use during the drought, but recovery occurred more quickly for plants in the lower and drier sites. Plants in drier sites also exhibited the greatest shifts in the osmotic potential at full saturation and the turgor loss point. Although all individuals survived this intense drought, epiphytes in the cloud forest experienced the slowest recovery, suggesting that plants in the TMCF are particularly sensitive to severe drought. Although vapor pressure deficit was an important driver of sap velocity in the highest elevation site, other factors, such as the volumetric water content of the canopy soil, were more important at lower (and warmer) sites.

Original languageEnglish
Pages (from-to)900-913
Number of pages14
JournalNew Phytologist
Volume219
Issue number3
DOIs
StatePublished - Aug 2018

Bibliographical note

Publisher Copyright:
© 2017 The Authors. New Phytologist © 2017 New Phytologist Trust

Keywords

  • El Niño
  • canopy water potential
  • drought
  • sap flow
  • tropical montane cloud forest (TMCF)
  • turgor loss point (TLP)
  • vapor pressure deficit (VPD)
  • volumetric water content

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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