Assessment of climate change impacts in the last 500 years through dendroclimatological and isotopic studies from trees at the Parque Nacional Cavernas do Peruaçu region

Author(s)

Milena de Godoy Veiga

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2023-07-04

Examining board members

Veronica Angyalossy; Ana Carolina Maioli Campos Barbosa; Peter Stoltenborg Groenendyk; Daniela Granato de Souza

• Advisor: Veronica Angyalossy; Giuliano Maselli Locosselli

Abstract

Climate change affects forests and biogeochemical cycles globaly. Assessing the effects in tropical forests is chalenging because instrumental records are constrained. Thus, tree rings proxies offer excelent anually resolved records of recent and pre-industrial climate variability, however few robusts chronologies are available for climate inferences in the tropics. Therefore, this thesis explored a new site in central-eastern Brazil, a hot spot of global warming in the tropics and a new tree species for dendrochronological investigations about the effects of climate change in a Seasonally Dry Tropical Forest (SDTF). In this work: we tested a new method for improving tree-ring identification; established Amburana cearensis tree-ring width and oxygen isotopes ratio (δ18O) chronologies at the National Park Cavernas do Peruaçu (PNCP); which were analysed with records of another representative species in the SDTF and speleothems to assess the effects of climate change in tree growth now and 500 year ago. Using the perfectly dated chronologies, with strong climate signal, we observed that trees of A. cearensis and C. fissilis grow regulated by rainfall amount during the growing season and the high evaporative demands in the recent years do not affect their growth yet. These findings are corroborated by data from subfossil samples and speleothem records that show another period of abrupt increase in evaporative demands during the Little Ice Age that did not leave traces in Amburana cearensis trees growth. Our results can aid scientists to develop new tree-ring chronologies with species that have complex wood anatomy; aid the development of new tropical chronologies; and understand the effects of climate change in SDTF trees growth. The data produced can also support the development of global vegetation models of SDTF responses to climate change. (AU)

• FAPESP's process: 18/07632-6 - Two-centuries of climate changes reconstruction through dendroclimatological and isotopic studies from trees at the Parque Nacional Cavernas do Peruaçu region
• Grantee: Milena de Godoy Veiga
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)