Indigenous brigades change the spatial patterns of wildfires, and the influence of climate on fire regimes

In their new study, Oliveira et al. express the importance and value of Indigenous knowledge and Indigenous brigades for the management of increasingly occurring wildfires.

Fire has been present in different biomes for millions of years and is a factor that can shape vegetation distribution patterns. However, lately there has been observed a higher frequency of growing wildfires that can cause great impacts on society and biodiversity. An example is the Pantanal wetland, in Brazil, where ca. 17 million terrestrial vertebrates died in the 2020 wildfires. That evidences the need for management strategies improvement. 

The recurrence of wildfires allowed indigenous people, who also occupied fire-prone environments for thousands of years, to accumulate vast knowledge on fire management. They utilize fire to manage natural resources in hunting, agriculture and animal husbandry, as a war strategy, for various cultural practices, and to prevent destructive wildfires. Despite evidence of the relevance of traditional indigenous knowledge on fire management, it was only recently incorporated in management policies.

Integrating fire management policies and traditional indigenous knowledge began with Integrated Fire Management (IFM) in Brazil. IFM aims to reduce the probability of large forest wildfires and their frequency in areas sensitive to fire. One of the IFM strategies is to form fire brigades to watch strategic territories, such as indigenous lands and conservation units. When in indigenous territories, the brigades are composed exclusively of indigenous residents, a way of integrating their traditional knowledge in management activities.

Indigenous brigades performing the prescribed burning at the IT Kadwéu. Photo: Alexandre M. M. Pereira.
Area where the prescribed burning was carried out by the indigenous brigade of IT Kadwéu. Photo: Alexandre M. M. Pereira.

However, little is known how management by indigenous brigades can change the patterns of wildfires where they act. Thus, in our study, we searched to answer questions: Do indigenous brigades reduce the burned area or the scale of forest fires? Does the fire management conducted by these brigades reduce wildfires in fire-sensitive vegetation? Does the fire management conducted by indigenous brigades alter the relation between climate and wildfires?

To answer these questions, we utilized the Kadiwéu Indigenous Land as a model, located in a Pantanal-Cerrado transition area, Brazilian biomes with high recurrence of wildfires. We mapped 18 years (2001-2018) fire scars (marks visible on satellite images because of vegetation removal by fire), analyzed spatial and temporal patterns, and related them to climatic factors and vegetation types. To verify the effect of indigenous brigades, we divided the 18 years into two periods, one without their action (2001-2008) and another with indigenous brigades (2009-2018).

We highlight a reduction of 53% of the mean burned area annually and the maximum size of fire scars during the indigenous brigade action compared without it. Besides, the management by indigenous brigades reduced high wildfire frequency by 80%. These results suggest that indigenous fire management efficiently reduces the frequency and extension of areas affected by wildfires and, thus, reduces their impact. We also observed that climatic conditions did not influence the wildfire patterns, and that is relevant since climate change can increase the incidence of extensive wildfires. Such changes in fire patterns can also be responsible for changes detected in the vegetation in the same period, such as increased forest area and stability of savanna environments.

Changes in the spatial distribution and in the frequency of wildfires due to the management carried out by the indigenous brigades in the IT Kadwéu.

Thus, our findings demonstrate that management by indigenous brigades can be considered an essential tool for fire management. Besides, our results show the importance of programs that integrate traditional indigenous knowledge and fire management policies such as Integrated Fire Management for building efficient management strategies.

Read the full paper Indigenous brigades change the spatial patterns of wildfires, and the influence of climate on fire regimes in Journal of Applied Ecology

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