Multiscale phenology of seasonally dry tropical forests in an aridity gradient

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Ramos, Desiree M. ; Andrade, Joao M. ; Alberton, Bruna C. ; Moura, Magna S. B. ; Domingues, Tomas F. ; Neves, Nattalia ; Lima, Jose R. S. ; Souza, Rodolfo ; Souza, Eduardo ; Silva, Jose R. ; Espirito-Santo, Mario M. ; Morellato, Leonor Patricia Cerdeira ; Cunha, John

• Tipo de documento: Artigo Científico
• Fonte: FRONTIERS IN ENVIRONMENTAL SCIENCE; v. 11, p. 16-pg., 2023-12-18.

Resumo

The leaf phenology of seasonally dry tropical forests (SDTFs) is highly seasonal, marked by synchronized flushing of new leaves triggered by the first rains of the wet season. Such phenological transitions may not be accurately detected by remote sensing vegetation indices and derived transition dates (TDs) due to the coarse spatial and temporal resolutions of satellite data. The aim of this study was to compared TDs from PhenoCams and satellite remote sensing (RS) and used the TDs calculated from PhenoCams to select the best thresholds for RS time series and calculate TDs. For this purpose, we assembled cameras in seven sites along an aridity gradient in the Brazilian Caatinga, a region dominated by SDTFs. The leafing patterns were registered during one to three growing seasons from 2017 to 2020. We drew a region of interest (ROI) in the images to calculate the normalized green chromatic coordinate index. We compared the camera data with the NDVI time series (2000-2019) derived from near-infrared (NIR) and red bands from MODIS product data. Using calibrated PhenoCam thresholds reduced the mean absolute error by 5 days for SOS and 34 days for EOS, compared to common thresholds in land surface phenology studies. On average, growing season length (LOS) did not differ significantly among vegetation types, but the driest sites showed the highest interannual variation. This pattern was applied to leaf flushing (SOS) and leaf fall (EOS) as well. We found a positive relationship between the accumulated precipitation and the LOS and between the accumulated precipitation and maximum and minimum temperatures and the vegetation productivity (peak and accumulated NDVI). Our results demonstrated that (A) the fine temporal resolution of phenocamera phenology time series improved the definitions of TDs and thresholds for RS landscape phenology; (b) long-term RS greening responded to the variability in rainfall, adjusting their timing of green-up and green-down, and (C) the amount of rainfall, although not determinant for the length of the growing season, is related to the estimates of vegetation productivity. (AU)

• Processo FAPESP: 19/11835-2 - Fenologia de florestas secas decíduas: uma comparação em múltiplas escalas utilizando fenocâmeras e drones
• Beneficiário: Leonor Patricia Cerdeira Morellato
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 13/50155-0 - Combining new technologies to monitor phenology from leaves to ecosystems
• Beneficiário: Leonor Patricia Cerdeira Morellato
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - PITE
• Processo FAPESP: 21/10639-5 - Centro de Pesquisa em Biodiversidade e Mudanças do Clima
• Beneficiário: Leonor Patricia Cerdeira Morellato
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 16/01413-5 - Utilizando a fenologia vegetativa para investigar os controladores de fluxo de energia dos ecossistemas em vegetações tropicais
• Beneficiário: Bruna de Costa Alberton
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado
• Processo FAPESP: 22/07735-5 - O impacto da variabilidade climática e dos extremos climáticos na fenologia vegetal e suas implicações na biodiversidade
• Beneficiário: Leonor Patricia Cerdeira Morellato
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático
• Processo FAPESP: 15/50488-5 - Nordeste: uma nova ciência para um importante, porém negligenciado bioma
• Beneficiário: Jonathan James Lloyd
• Modalidade de apoio: Auxílio à Pesquisa - Programa SPEC
• Processo FAPESP: 14/00215-0 - Fenologia remota e os padrões de trocas foliares ao longo de um gradiente de sazonalidade
• Beneficiário: Bruna de Costa Alberton
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 09/54208-6 - EMU: Laboratório Multiusuário Centralizado do Núcleo de Estudos em Biodiversidade da UNESP
• Beneficiário: Célio Fernando Baptista Haddad
• Modalidade de apoio: Auxílio à Pesquisa - Programa Equipamentos Multiusuários
• Processo FAPESP: 17/17380-1 - Fenologia remota próxima e atributos foliares de vegetações sazonais
• Beneficiário: Desirée Marques Ramos
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado