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Ecosystem heterogeneity and diversity mitigate Amazon forest resilience to frequent extreme droughts
Author(s) -
Longo Marcos,
Knox Ryan G.,
Levine Naomi M.,
Alves Luciana F.,
Bonal Damien,
Camargo Plinio B.,
Fitzjarrald David R.,
Hayek Matthew N.,
RestrepoCoupe Natalia,
Saleska Scott R.,
Silva Rodrigo,
Stark Scott C.,
Tapajós Raphael P.,
Wiedemann Kenia T.,
Zhang Ke,
Wofsy Steven C.,
Moorcroft Paul R.
Publication year - 2018
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.15185
Subject(s) - amazon rainforest , environmental science , biomass (ecology) , evergreen , ecosystem , forest ecology , climate change , forest structure , agroforestry , physical geography , canopy , ecology , geography , biology
Summary The impact of increases in drought frequency on the Amazon forest's composition, structure and functioning remain uncertain. We used a process‐ and individual‐based ecosystem model ( ED 2) to quantify the forest's vulnerability to increased drought recurrence. We generated meteorologically realistic, drier‐than‐observed rainfall scenarios for two Amazon forest sites, Paracou (wetter) and Tapajós (drier), to evaluate the impacts of more frequent droughts on forest biomass, structure and composition. The wet site was insensitive to the tested scenarios, whereas at the dry site biomass declined when average rainfall reduction exceeded 15%, due to high mortality of large‐sized evergreen trees. Biomass losses persisted when year‐long drought recurrence was shorter than 2–7 yr, depending upon soil texture and leaf phenology. From the site‐level scenario results, we developed regionally applicable metrics to quantify the Amazon forest's climatological proximity to rainfall regimes likely to cause biomass loss > 20% in 50 yr according to ED 2 predictions. Nearly 25% (1.8 million km 2 ) of the Amazon forests could experience frequent droughts and biomass loss if mean annual rainfall or interannual variability changed by 2σ. At least 10% of the high‐emission climate projections ( CMIP 5/ RCP 8.5 models) predict critically dry regimes over 25% of the Amazon forest area by 2100.