Seasonal and drought-related changes in leaf area profiles depend on height and light environment in an Amazon forest

Autor(es):Mostrar menos -

Smith, Marielle N. ^{[1, 2]} ; Stark, Scott C. ^[1] ; Taylor, Tyeen C. ^[2] ; Ferreira, Mauricio L. ^[3] ; de Oliveira, Eronaldo ^[4] ; Restrepo-Coupe, Natalia ^{[2, 5]} ; Chen, Shuli ^[2] ; Woodcock, Tara ^[2] ; dos Santos, Darlisson Bentes ^[6] ; Alves, Luciana F. ^[7] ; Figueira, Michela ^[4] ; de Camargo, Plinio B. ^[3] ; de Oliveira, Raimundo C. ^[8] ; Aragao, Luiz E. O. C. ^{[9, 10]} ; Falk, Donald A. ^{[11, 12]} ; McMahon, Sean M. ^[13] ; Huxman, Travis E. ^{[14, 15]} ; Saleska, Scott R. ^[2]

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^[1] Michigan State Univ, Dept Forestry, E Lansing, MI 48824 - USA

^[2] Univ Arizona, Ecol & Evolutionary Biol, Tucson, AZ 85721 - USA

^[3] Univ Sao Paulo, CENA, BR-13416000 Piracicaba, SP - Brazil

^[4] Univ Fed Oeste Para UFOPA, BR-68040255 Santarem, PA - Brazil

^[5] Univ Technol Sydney, Sch Life Sci, Sydney, NSW 2007 - Australia

^[6] Ctr Univ Luterano Santarem CEULS ULBRA, BR-68025000 Santarem, PA - Brazil

^[7] Univ Calif Los Angeles, Inst Environm & Sustainabil, Ctr Trop Res, Los Angeles, CA 90095 - USA

^[8] Embrapa Amazonia Oriental, BR-68035110 Santarem, PA - Brazil

^[9] Inst Nacl Pesquisas Espaciais, BR-12227010 Sao Jose Dos Campos, SP - Brazil

^[10] Univ Exeter, Coll Life & Environm Sci, Exeter EX4 4RJ, Devon - England

^[11] Univ Arizona, Sch Nat Resources & Environm, Tucson, AZ 85721 - USA

^[12] Univ Arizona, Tree Ring Res Lab, Tucson, AZ 85721 - USA

^[13] Smithsonian Environm Res Ctr, Smithsonian Inst Forest Global Earth Observ, POB 28, Edgewater, MD 21037 - USA

^[14] Univ Calif Irvine, Ecol & Evolutionary Biol, Irvine, CA 92629 - USA

^[15] Univ Calif Irvine, Ctr Environm Biol, Irvine, CA 92629 - USA

• Tipo de documento: Artigo Científico
• Fonte: NEW PHYTOLOGIST; v. 222, n. 3, p. 1284-1297, MAY 2019.
• Citações Web of Science: 7

Resumo

Seasonal dynamics in the vertical distribution of leaf area index (LAI) may impact the seasonality of forest productivity in Amazonian forests. However, until recently, fine-scale observations critical to revealing ecological mechanisms underlying these changes have been lacking. To investigate fine-scale variation in leaf area with seasonality and drought we conducted monthly ground-based LiDAR surveys over 4 yr at an Amazon forest site. We analysed temporal changes in vertically structured LAI along axes of both canopy height and light environments. Upper canopy LAI increased during the dry season, whereas lower canopy LAI decreased. The low canopy decrease was driven by highly illuminated leaves of smaller trees in gaps. By contrast, understory LAI increased concurrently with the upper canopy. Hence, tree phenological strategies were stratified by height and light environments. Trends were amplified during a 2015-2016 severe El Nino drought. Leaf area low in the canopy exhibited behaviour consistent with water limitation. Leaf loss from short trees in high light during drought may be associated with strategies to tolerate limited access to deep soil water and stressful leaf environments. Vertically and environmentally structured phenological processes suggest a critical role of canopy structural heterogeneity in seasonal changes in Amazon ecosystem function. (AU)

• Processo FAPESP: 13/50533-5 - Entendendo as respostas do metabolismo fotossintético a variações climáticas sazonais em florestas tropicais
• Beneficiário: Luiz Eduardo Oliveira e Cruz de Aragão
• Modalidade de apoio: Auxílio à Pesquisa - Regular