Researchers assess phenological changes in dry tropical ecosystems in Brazil and Africa

Por: Gabriela Andrietta

The PhenoChange project, an international initiative that studies phenological changes in dry tropical ecosystems, had its results presented at a Workshop held at the Cavernas do Peruaçú National Park, in Minas Gerais, in December 2024. The meeting brought together researchers from Brazil and the United Kingdom to discuss the progress made at nine study sites – five in Brazil and four in Africa – and to plan future actions that will contribute to the understanding of the impacts of climate change on vegetation. This was the group’s third workshop. The first was in Brazil in 2022 and the second in Namibia in 2023, supported by the FAPESP/UKRI-NERC project described below.

Workshop realizado no Parque Nacional Cavernas do Peruaçú, em Minas Gerais, em dezembro de 2024.

The idea of ​​phenological monitoring, which began in 2020 as part of the SECO project (https://blogs.ed.ac.uk/seco-project/), in continuation of the FAPESP Nordeste project and supported by the Brazilian e-phenology network, was realized in the proposal PhenoChange: Towards a Dry Tropics Global Phenological Monitoring Network (FAPESP 2022/02323-0) submitted and approved within the call for FAPESP - UKRI (UK Research and Innovation)/NERC (Natural Environment Research Council) Cooperation Agreements. The PhenoChange research proposal, led by Dr. Patrícia Morellato (Brazil) and Dr. Kyle Dexter (United Kingdom) and coordinated by Dr. Desiree Ramos, uses a network of 80 phenocameras to monitor savannas and dry forests on both continents.

Esquema de desenho experimental feito por Mateus Silva

In Brazil, most of the cameras are located in the Cerrado, a major seasonally dry tropical ecosystem recognized as the richest savannah in the world. The cameras, installed at strategic points, capture images of the vegetation every hour, allowing researchers to analyze seasonal variations in plant production and leaf fall. Monitoring is carried out along a precipitation gradient across both continents, focusing simultaneously on both tree and herbaceous strata, making PhenoChange a comprehensive project in the dry tropics.

Caatinga

Preliminary results indicate that vegetation tends to behave more similarly within the same continent than between different continents.

Preliminary results presented at the Workshop revealed that leaf production patterns of trees along the precipitation gradient differ between continents, while no such difference was observed for herbaceous plants. On the other hand, the responses of herbaceous plants show great local variation, possibly associated with floristic composition. This suggests that the evolutionary history and floristic composition of each region play as important a role as climate in determining plant behavior.

 Savana árida em Ongava Research Centre, Namíbia.

“Floristic diversity, especially in the herbaceous layer, is crucial to understanding local responses,” explained researcher Dr. Desirée Ramos, co-founder of the PhenoChange network, who presented results from the data collected by the projects. Another focus of the project is to understand how leaf production cycles influence carbon storage in these ecosystems. “The period in which plants have leaves is essential to determine whether they are capturing and storing carbon,” highlighted Desirée Ramos.

Challenges Faced

The challenges faced by the team are as diverse as the ecosystems they study. For example, in Africa, fires and elephants often damage cameras, requiring researchers to work with armed guides. In Brazil, the main obstacle has been the risk of equipment being damaged or stolen.

Challenges in using fencams in Bicuar National Park, Angola. On the left, the image shows a fire just before it hits and destroys the equipment. On the right, an elephant is captured just before it damages the camera. The close-up images at the top reveal the impacts caused to the equipment.

Scientific and Climate Impact

PhenoChange represents one of the largest efforts ever undertaken to understand how dry ecosystems in the tropics respond to climate change. These areas, which cover more than 50% of the tropics, play a crucial role in the variability of global carbon fluxes, directly influencing the planet’s climate. Understanding their behavior is essential to predict future scenarios and develop biodiversity conservation strategies.

 Parque Nacional do Bicuar, Angola.

Conclusion and Next Steps

The FAPES-UKRI PhenoChange project was completed last year, but the PhenoChange network's research continues with support from CBioClima (FAPESP 2021/10639-5) and in search of new funding. The expectation is that its findings will contribute not only to science, but also to the formulation of public policies aimed at mitigating the effects of climate change. Continued data collection and the development of new research will ensure significant advances in the understanding of these ecosystems and their relationship with the global climate.

Animal with its young on its back at Água Limpa Farm, UnB.