The resilience of Amazon tree cover to past and present drying

Research output: Contribution to journalArticle

Abstract

The Amazon forest is increasingly vulnerable to dieback and encroachment of grasslands and agricultural fields. Threats to these forested ecosystems include drying, deforestation, and fire, but feedbacks among these make it difficult to determine their relative importance. Here, we reconstruct the central and western Amazon tree cover response to aridity and fire in the mid-Holocene—a time of less intensive human land use and markedly drier conditions than today—to assess the resilience of tree cover to drying and the strength of vegetation-climate feedbacks. We use pollen, charcoal, and speleothem oxygen isotope proxy data to show that Amazon tree cover in the mid-Holocene was resilient to drying in excess of the driest bias-corrected future precipitation projections. Experiments with a dynamic global vegetation model (LPJ-GUESS) suggest tree cover resilience may be owed to weak feedbacks that act to amplify tree cover loss with drying. We also compare these results to observational data and find that, under limited human interference, modern tree cover is likely similarly resilient to mid-Holocene levels of aridification. Our results suggest human-driven fire and deforestation likely pose a greater threat to the future of Amazon ecosystems than drying alone.

Details

Authors
Organisations
External organisations
  • Stanford University
  • University of Bonn
  • University of Lausanne
  • University of Massachusetts
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Climate Research

Keywords

  • Amazon resilience, Dynamic global vegetation model, Fire, Mid-Holocene, Oxygen isotopes, Pollen
Original languageEnglish
Article number103520
JournalGlobal and Planetary Change
Volume202
Publication statusPublished - 2021 Jul 1
Publication categoryResearch
Peer-reviewedYes