Is fire always the “bad guy”?

doi:10.1016/j.flora.2020.151611

Flora

Volume 268, July 2020, 151611

https://doi.org/10.1016/j.flora.2020.151611 Get rights and content

Highlights

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Fire is usually linked to negative impacts and thus, it is considered to be the “bad guy”.
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Wildfires are usually viewed as destructive, reinforcing the negative view of fire from the general public.
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Fire is an important ecological and evolutionary factor in several ecosystems in the world.
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Fire affects differently fire-sensitive ecosystems from fire-prone ecosystems.•When, where and how fire occurs should be considered for understanding its effects on ecosystem diversity and services.

Abstract

Much distortion about the real role of fire in different ecosystems exists, mostly because fire events attract media attention, usually focusing on the negative aspects of fire. In the perception of the general public, fire events are usually linked to disasters that affect humans in several ways, from losses of lives to negative effects on human well-being. However, while some ecosystems are fire-sensitive and fire will thus bring more negative than positive effects (e.g. in tropical rain forests), other systems are fire-prone and depend on fire in their existence and ecological characteristics (e.g. in savannas). In this paper, I show the different sides of fire, trying to elucidate its evolutionary and ecological role in fire-prone ecosystems and the consequences of wildfires in fire-sensitive ecosystems. Finally, I make a case for the need to debate how the misinterpretation of the role of fire as being always the “bad guy” can threaten fire-prone, but protect fire-sensitive vegetation.

Section snippets

Are fires always human-caused?

Firstly, not all fires are anthropogenic, and their occurrence is not only related to the presence of humans. Fire has been present in the planet since the end of the Silurian (ca. 420 million year BP), long before the rise of humans (Scott and Glasspool, 2006). Therefore, the first records of fire in the planet are directly related to the emergence of the first plants (fuel load), that led to increases in the concentration of oxygen in the atmosphere, as well as a source of ignition, such as

How does fire (regime) affect the vegetation?

When we think about the fire effects on vegetation, we must first understand that the vegetation is not influenced by fire, but by fire regime (frequency, season, extension and intensity / severity; Keeley et al., 2011). Further, not all wildfires must be considered “bad”, because when humans were not present on the planet, fire spread for long distances with neither intervention (e.g. people extinguishing fire) nor barriers (e.g. habitat fragmentation, cities, etc.). Thus, these fires would be

Fire-prone vs. fire-sensitive vegetation: It matters!

Fire is not always “good” or “bad”. It will depend on where, when and how it occurs. In fire-sensitive systems, fire might bring more negative than positive outcomes, while in fire-prone ecosystems, fire is an ecological and evolutionary factor maintaining ecosystem diversity and services and thus, it may not be considered as the “bad guy”. Some ecosystems (e.g. tropical grassy ecosystems) are resilient to fire and usually need fire to maintain their diversity and ecosystem services. On the

CRediT authorship contribution statement

Alessandra Fidelis: Conceptualization, Writing - original draft, Writing - review & editing.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

I thank Dr. Hermann Heilmeier and the Subject Editors for the invitation, and also I thank them and the reviewers for their valuable suggestions that improved this manuscript. I also thank FAPESP (FAPESP 2015/06743-0) for the financial support on experimental fires in the Cerrado, that gave me all the background to write this manuscript and CNPq for the productivity grant (303988/2018-5). Finally, I thank all fire managers and brigade, local decision-makers and local people, who taught me so

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The year 2017: megafires and management in the cerrado

Fire

(2018)

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2022, Flora: Morphology, Distribution, Functional Ecology of Plants
Woody plant encroachment (WPE) is a process that lead to the transformation of savanna environments into forests, and in the threatened Central Brazilian savanna (locally called Cerrado) it is a result of inadequate conservation policies. Here, we compared the floristic and functional attributes of the adult (trees with diameter at ground level ≥ 5 cm) and juvenile (trees with diameter at ground level < 5 cm) components in a Cerrado sensu stricto to assess changes in a plant formation under a process of woody encroachment. We found that the adult and juvenile components had a mean Jaccard similarity index of 19% and PERMANOVA analysis showed a separation of two clusters (species of the adult component and species of the juvenile component), indicating high species dissimilarity between both components. We also found a higher percentage of forest species, with lower bark thickness and dispersed by animals in the juvenile component compared to the adult component. Our results indicate that under a process of WPE, forest species less adapted to stressful conditions and fire can establish in the juvenile component and may reflect environmental changes as increasing shade, reduced fire and lower temperatures. Considering that Cerrado is becoming hot and drier, our results alert that WPE can make Brazilian savanna ecosystems more vulnerable to global climate changes, since it selects species less resistant to fire. Our sampling approach is useful to detect further encroachment in Cerrado throughout short-term plant inventories.
Fire and vegetation: Introduction to the special issue
2022, Flora: Morphology, Distribution, Functional Ecology of Plants
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We hope that the present Special Issue ‘Fire and Vegetation’ contributes to filling these gaps, stimulates further research and, ultimately, helps to inform fire management practice to improve human well-being, the sustainability of resource use, and perhaps most important, biodiversity conservation and climate change mitigation. Papers in this Special Issue cover a wide diversity of biogeographic regions but are concentrated in the Neotropics which is also the region that the Opinion Papers (Berlinck and Batista, 2020; Brando et al., 2020; Durigan, 2020; Schmidt and Eloy, 2020; Fidelis, 2020), briefly presented in Overbeck et al. (2020), focus on. The research papers (one of them a review) address basic aspects of fire ecology in places traditionally underrepresented in the ecological literature (Nuñez et al., 2021).
Fires are widespread disturbance events with many implications for different aspects of plant persistence and vegetation properties. Changing fire regimes can profoundly affect vegetation dynamics and ecosystem properties. Recent steep increases in the frequency of fires worldwide and the occurrence of megafires have caught the attention of scientists, policymakers, and the media. The FLORA Special Issue on Fire and Vegetation unites five invited Opinion Papers with emphasis on South America and nineteen research papers, including one review, on different aspects of the fire–vegetation interaction. The studies contribute both to the discussion of how to better manage fire in ecosystems and to improve our understanding of fire effects on organisms, communities, and ecosystems. Our expectation is that the Special Issue stimulates further research and, ultimately, helps to inform fire management practice to improve human well-being, to ensure the sustainability of resource use, and perhaps most important, biodiversity conservation and climate change mitigation.
The influence of fire and cattle grazing on Araucaria population structure in forest-grasslands mosaics
2021, Flora: Morphology, Distribution, Functional Ecology of Plants
Citation Excerpt :
Climate is the main driver of broad global vegetation patterns, such as the distribution of forests or open vegetation. However, in certain regions such as the Brazilian Cerrado or in African savannas, disturbance by fire or grazing by large herbivores controls vegetation structure and dynamics, determining the occurrence of open, non-forested vegetation (Bond and Keeley, 2005; Fidelis, 2020; Schmidt and Eloy, 2020). In the highlands of southern Brazil, subtropical grasslands coexist with mixed forests in mosaics, in most cases forming abrupt boundaries (Klein, 1984; Rambo, 1956).
Disturbances caused by land management via fire and cattle grazing can alter the population structure of keystone species that change the output of vegetation dynamics. Adult araucaria trees (Araucaria angustifolia) can facilitate the establishment of other woody plants and, thus, influence the expansion of forests over grasslands in the highlands of southern Brazil. Here we aimed to check araucaria population structure under two types of management – with or without fire and grazing– and in three habitat types: forests, shrublands and grasslands. We sampled araucaria populations in 40 transects (100×4 m), half of each located in the forest, and the other half, in variable extensions of shrublands or grasslands. Of the 40 transects, 18 were under management with fire and grazing and 22 in a protected area where the two disturbances are prevented (São Joaquim National Park). Overall, we sampled 339 araucaria seedlings, 59 saplings, 44 juveniles and 128 adults. Population structure differed both among habitats, between types of management, and between the same habitats but under distinct types of management. Population density was 1.4 times higher in areas with fire and grazing than without such disturbances, which was caused mostly by a larger number of seedlings. Under fire and grazing, we found 1.4 times more adults in forests, 5.7 times more seedlings in shrublands and 5.3 times more seedlings in the grassland than in the same habitat but without disturbances. Our results indicate that araucarias reach and germinate under all conditions but rarely surpass the seedling stage in grasslands and shrublands where fire and grazing is used. Consequently, fire and grazing disturbances should slow down forest expansion over shrublands and grasslands. In contrast, when disturbances are barred, araucarias can grow large enough to trigger their facilitative effect and then gear up the pace of forest expansion.
Management, sustainability and research perspective of prescribed fires in tropical parks
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Citation Excerpt :
Especially in Brazil, the population and part of political administrators still mistake fire management with the effects of wildfire arson, burning with agricultural purposes or still, fire in nonadapted biomes. News stories on the 2019 wildfire arsons in the Amazon Rainforest helped distort the role of fire in ecosystems that need it for their own maintenance [21]. There is still no universal prescription for fire management, but it is known that fire suppression policies are not viable in savannas [13,16].
Relevant studies on prescribed fires in tropical parks published in the past 2 years were analyzed considering both political/social issues and environmental effects. Prescribed burning application and regulation in protected areas is recent in Australia, Africa and Brazil. Recognition of traditional indigenous fire practices and improved communication between managers, scientists and local communities has been in great demand. Current studies show concerns about environmental responses to different characteristics of fire management, but also some advantages. Considering the importance of prescribed fires for the conservation of tropical ecosystems, more research on the effects of such practices on fauna and flora is necessary, but also on other environment regulating factors, such as soil.
Understanding Brazil's catastrophic fires: Causes, consequences and policy needed to prevent future tragedies
2021, Perspectives in Ecology and Conservation
Citation Excerpt :
This gives us hope that we will also advance in fire management across the country, with solutions that are adequate for the distinct ecological, socio-economic and cultural realities of Brazil. From the text above, it becomes clear that fire cannot be generalized to be always harmful (Fidelis, 2020). A nuanced perspective is needed that considers regional particularities including ecosystem types and their historical evolution as well as the socio-economic context to support policy.
Brazil has experienced unprecedented wildfires in the last decade. Images of immense burnt areas or dead animals that failed to escape the 2020 wildfires have shocked the world. To prevent or minimize further similar disasters we must understand the factors that have led to these catastrophic events. The causes and consequences of wildfires entail complex interactions between the biophysical and sociocultural spheres, and suitable management decisions require a sound scientific base. We present the recent panorama of increasing fire outbreaks in the Brazilian biomes, and discuss the causes that have contributed to such fires, their impacts on the environment and overall consequences for human well-being, based on reviewing the extensive specialist literature, on authors’ expert knowledge and information provided by environmental managers, researchers and politicians during a workshop organized to debate the wildfire issue in Brazil. Our up-to-date review is aimed at the academic public, environmental managers and decision- and policy-makers. First, we present evidence on the contrasting effects of fire on different ecosystems. Second, we outline the historic perceptions and policies related to fire use and management in Brazil since its colonization to the present date. Third, we propose means to advance fire prevention and develop successful management strategies. Finally, we answer frequently asked questions to clarify and/or demystify some fire-related issues not always properly addressed in the media.
To graze or not to graze: A core question for conservation and sustainable use of grassy ecosystems in Brazil
2021, Perspectives in Ecology and Conservation
Differently from commonly used forest conservation strategies, the absence of disturbance in non-forest-ecosystems can result in loss of biodiversity. Grassy ecosystems characterize extensive areas in all biomes in Brazil, offering great contribution to biological diversity and providing ecosystem services on which society depends. Palaeoecological evidence indicates these ecosystems evolved under the influence of grazing and fire, and these disturbances have been essential for controlling the dominance of woody vegetation. While the need for fire to maintain grassy biomes has been recently discussed, grazing as a management tool for conservation is still little accepted by the local scientific community and by decision-makers. Here we provide a comprehensive analysis of the current literature on grazing management and its effects on grassy ecosystems in Brazil. Based on a review of the role of grazers prior and after European colonization, and a synthesis on grazing effects across different systems, we call for the evaluation of grazing as a management tool for biodiversity conservation in Brazil’s grassy systems. Grazing should be an interesting management strategy especially in Legal Reserves with grassy vegetation types, as it can ally conservation with livestock production. To achieve these potentially complementary objectives, a research agenda needs to be developed to devise adaptive management strategies for Legal Reserves. In this, relevant stakeholders should be included and both the ecological conditions of the ecosystem in question and the socioeconomic determinants considered.

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View full text

Is fire always the “bad guy”?

Highlights

Abstract

Section snippets

Are fires always human-caused?

How does fire (regime) affect the vegetation?

Fire-prone vs. fire-sensitive vegetation: It matters!

CRediT authorship contribution statement

Declaration of Competing Interest

Acknowledgments

Trends Plant Sci.

For. Ecol. Manage.

The biodiversity cost of carbon sequestration in tropical savanna

Sci. Adv.

Defining pyromes and global syndromes of fire regimes

Proc. Natl. Acad. Sci.

Switching on the big burn of 2017

Fire

Clarifying Amazonia’s burning crisis

Glob. Chang. Biol.

Fire and the spread of flowering plants in the Cretaceous

New Phytol.

Fire in the Earth system

Science

The origins of C 4 grasslands: integrating evolutionary and ecosystem science

Science

Short‐term changes caused by fire and mowing in Brazilian Campos grasslands with different long‐term fire histories

J. Veg. Sci.

The year 2017: megafires and management in the cerrado

Fire