Basin-wide variation in tree hydraulic safety margins predicts the carbon balance of Amazon forests

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Tavares, Julia Valentim ; Oliveira, Rafael S. ; Mencuccini, Maurizio ; Signori-Mueller, Caroline ; Pereira, Luciano ; Diniz, Francisco Carvalho ; Gilpin, Martin ; Zevallos, Manuel Marca J. ; Yupayccana, Carlos Salas A. ; Acosta, Martin ; Mullisaca, Flor Perez ; Barros, Fernanda de V. ; Bittencourt, Paulo ; Jancoski, Halina ; Scalon, Marina Correa ; Marimon, Beatriz S. ; Menor, Imma Oliveras ; Marimon Jr, Ben Hur ; Fancourt, Max ; Chambers-Ostler, Alexander ; Esquivel-Muelbert, Adriane ; Rowland, Lucy ; Meir, Patrick ; da Costa, Antonio Carlos Lola ; Nina, Alex ; Sanchez, Jesus M. B. ; Tintaya, Jose S. ; Chino, Rudi S. C. ; Baca, Jean ; Fernandes, Leticia ; Cumapa, Edwin R. M. ; Santos, Joao Antonio R. ; Teixeira, Renata ; Tello, Ligia ; Ugarteche, Maira T. M. ; Cuellar, Gina A. ; Martinez, Franklin ; Araujo-Murakami, Alejandro ; Almeida, Everton ; da Cruz, Wesley Jonatar Alves ; Pasquel, Jhon del Aguila ; Aragao, Luis ; Baker, Timothy R. ; de Camargo, Plinio Barbosa ; Brienen, Roel ; Castro, Wendeson ; Ribeiro, Sabina Cerruto ; de Souza, Fernanda Coelho ; Cosio, Eric G. ; Cardozo, Nallaret Davila ; Silva, Richarlly da Costa ; Disney, Mathias ; Espejo, Javier Silva ; Feldpausch, Ted R. ; Ferreira, Leandro ; Giacomin, Leandro ; Higuchi, Niro ; Hirota, Marina ; Honorio, Euridice ; Huasco, Walter Huaraca ; Lewis, Simon ; Llampazo, Gerardo Flores ; Malhi, Yadvinder ; Mendoza, Abel Monteagudo ; Morandi, Paulo ; Moscoso, Victor Chama ; Muscarella, Robert ; Penha, Deliane ; Rocha, Mayda Cecilia ; Rodrigues, Gleicy ; Ruschel, Ademir R. ; Salinas, Norma ; Schlickmann, Monique ; Silveira, Marcos ; Talbot, Joey ; Vasquez, Rodolfo ; Vedovato, Laura ; Vieira, Simone Aparecida ; Phillips, Oliver L. ; Gloor, Emanuel ; Galbraith, David R.

• Document type: Journal article
• Source: Nature; v. N/A, p. 27-pg., 2023-04-26.

Abstract

Tropical forests face increasing climate risk(1,2), yet our ability to predict their response to climate change is limited by poor understanding of their resistance to water stress. Although xylem embolism resistance thresholds (for example, ?(50)) and hydraulic safety margins (for example, HSM50) are important predictors of drought-induced mortality risk(3-5), little is known about how these vary across Earth's largest tropical forest. Here, we present a pan-Amazon, fully standardized hydraulic traits dataset and use it to assess regional variation in drought sensitivity and hydraulic trait ability to predict species distributions and long-term forest biomass accumulation. Parameters ?(50) and HSM50 vary markedly across the Amazon and are related to average long-term rainfall characteristics. Both ?(50) and HSM50 influence the biogeographical distribution of Amazon tree species. However, HSM50 was the only significant predictor of observed decadal-scale changes in forest biomass. Old-growth forests with wide HSM50 are gaining more biomass than are low HSM(50 )forests. We propose that this may be associated with a growth-mortality trade-off whereby trees in forests consisting of fast-growing species take greater hydraulic risks and face greater mortality risk. Moreover, in regions of more pronounced climatic change, we find evidence that forests are losing biomass, suggesting that species in these regions may be operating beyond their hydraulic limits. Continued climate change is likely to further reduce HSM50 in the Amazon(6,7), with strong implications for the Amazon carbon sink. (AU)

• FAPESP's process: 13/50531-2 - Ecophysiological controls on Amazonian precipitation seasonality and variability
• Grantee: Laura de Simone Borma
• Support Opportunities: Research Program on Global Climate Change - Regular Grants
• FAPESP's process: 13/50533-5 - Understanding the response of photosynthetic metabolism in tropical forests to seasonal climate variations
• Grantee: Luiz Eduardo Oliveira e Cruz de Aragão
• Support Opportunities: Regular Research Grants
• FAPESP's process: 11/52072-0 - Soil-plant-atmosphere interactions in a changing tropical landscape
• Grantee: Rafael Silva Oliveira
• Support Opportunities: Research Grants - Research Partnership for Technological Innovation - PITE