Article

The need for a consistent fire policy for Cerrado conservation

Authors:
  • Instituto de Pesquisas Ambientais - Governo do Estado de São Paulo
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Abstract

The Cerrado is a fire-dependent savanna requiring a clear and urgent fire management policy. The extensive misuse of fire for deforestation or pasture management in Brazil has created an overall perception that its use is always deleterious. This view, reinforced by threats of global warming and climatic change, has lead to current policies of fire suppression. Cerrado ecosystems depend on the historical fire regime to maintain their structure, biodiversity and functioning. The suppression of fire has transformed savanna vegetation into forests, causing biodiversity losses and drastic changes in ecological processes. Policy implications. The National Fire Policy required by law must be urgently implemented in Brazil, including use of fire for Cerrado conservation in public and private lands on the basis of existing knowledge of indigenous people and scientists. Objective regulations on prescribed burning, land manager training, incentives for fire research and experimentation and a broad campaign to disseminate the benefits of fire for Cerrado conservation should be the cornerstones of the policy. If implemented, the policy can give the biodiversity of the Cerrado a future that has previously been severely threatened by fire suppression.

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... We divided the study period (2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018), where satellite-derived information is available) into 3 distinct phases: NFP consists of the period from 2003 to 2007 when there was almost a lack of consistent fire policies over the region [44], hereafter the "No Fire-policy Phase". ZFP includes the period from 2008 until 2013, when a total fire suppression policy, hereafter the "Zero Fire Phase", was applied [16,17,85]. Finally, IFMP goes from 2014 to 2018, thus representing the IFM implementation including "controlled" and "prescribed" burns, hereafter the "Integrated Fire Management Phase". ...
... An important aspect of fire management in the Brazilian savanna is that IFM is still only implemented in federal PA, including ITs, and wildfires during the WFS are still very common in most remnant vegetation in the Cerrado [50]. In private areas, fire policies are badly implemented, with bureaucratic burning permits that are usually not granted to (or even demanded by) farmers who commonly used illegal, and therefore untanned fires to manage their lands, resulting in frequent wildfires, which can even reach PAs and ITs [17]. This fact highlights the importance of a national fire management policy implementation that allows for the effective use of prescribed and controlled fires over different land ownership contexts. ...
... Brazil was one of the last countries with tropical savannas to adopt an effective fire management policy. This resistance to change from a zero-fire policy to the presently implemented IFM program can be explained by a historical colonial legacy [6,16,17,55], but also by considerable uncertainty related to the effects of different fire regimes on very diverse ecosystems [4,42]. Since local communities are deeply involved in fire management activities and in a landscape where fire ignitions are predominantly human, the exchange of knowledge among environmental managers, researchers, and these traditional communities is essential to develop strategies to better conserve tropical savannas [108,113]. ...
Article
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Brazil has recently (2014) changed from a zero-fire policy to an Integrated Fire Management (IFM) program with the active use of prescribed burning (PB) in federal Protected Areas (PA) and Indigenous Territories (IT) of the Brazilian savanna (Cerrado). PB is commonly applied in the management of fire-prone ecosystems to mitigate large, high-intensity wildfires, the associated emissions, and high fire suppression costs. However, the effectiveness of such fire management in reducing large wildfires and emissions over Brazil remains mostly unevaluated. Here, we aim to fill the gap in the scientific evidence of the PB benefits by relying on the most up-to-date, satellite derived fire datasets of burned area (BA), fire size, duration, emissions, and intensity from 2003 to 2018. We focused on two Cerrado ITs with different sizes and hydrological regimes, Xerente and Araguaia, where IFM has been in place since 2015. To understand fire regime dynamics, we divided the study period into three phases according to the prevalent fire policy and the individual fire scars into four size classes. We considered two fire seasons: management fire season (MFS, which goes from rainy to mid-dry season, when PBs are undertaken) and wildfires season (WFS, when PBs are not performed and fires tend to grow out of control). Our results show that the implementation of the IFM program was responsible for a decrease of the areas affected by high fire recurrence in Xerente and Araguaia, when compared with the Zero Fire Phase (2008–2013). In both regions, PB effectively reduced the large wildfires occurrence, the number of medium and large scars, fire intensity, and emissions, changing the prevalent fire season from the WFS to the MFS. Such reductions are significant since WFS causes higher negative impacts on biodiversity conservation and higher greenhouse gas emissions. We conclude that the effect on wildfires can still be reduced if effective fire management policies, including PB, continue to be implemented during the coming decades.
... For instance, in Brazil, fire management policies only began to integrate traditional indigenous knowledge in 2014, using Integrated Fire Management (IFM; Eloy L et al., 2019;Schmidt et al., 2018). Previously, for decades the adopted policy was 'zero fire', with no burning (Durigan & Ratter, 2016;Schmidt et al., 2018). ...
... However, this 'zero fire' policy has proven ineffective, as it leads to fuel building up and the consequent fire becomes more intense, with severe consequences on biodiversity and people (Durigan & Ratter, 2016). Integrated Fire Management considers local circumstances, including the vegetation types present, to define the best management (Schmidt et al., 2018). ...
Article
1. Indigenous peoples have been managing fire‐prone landscapes for millennia, especially in tropical savannas, thereby maintaining carbon stocks and pyrodiversity and ensuring food security. In some indigenous lands in Brazil, fire brigades are composed of indigenous people, integrating their traditional knowledge in Brazilian fire management policies; however, the effectiveness of their management is largely undocumented. Nevertheless, we need to know the effectiveness of indigenous fire brigades and their influence on fire patterns. 2. Here, we evaluate an 18‐year historical series of fire patterns and burn scars, comparing periods with and without indigenous brigade activity, to describe the role of indigenous fire brigades in the Kadiwéu Indigenous Territory. In this Indigenous Territory, fire brigades composed of indigenous people have been instituted, trained and maintained by the National Center of Prevention and Combat of Wildfire (PREVFOGO/IBAMA) since 2009. These brigades are responsible for fire management throughout the Kadiwéu Indigenous Territory using controlled burning, prescribed burning, and combating wildfires. 3. We found that fire management by the indigenous brigades has reduced fire frequency by 80% in the areas with high fire frequency (over 70% of the analyzed time). Management also reduced the size of the area burned by 53% and the influence of climate over the total area burned. According to our models, the area affected by fires is mainly influenced by annual rainfall in the absence of indigenous brigades; in contrast, climatic factors could not explain the variation in the burned area in the period without indigenous brigades. 4. Synthesis and applications — The fire management realized by the indigenous brigades can modify the fire regime. These changes in the fire regime can include: changes in spatial patterns, the magnitude of fires, and reduction in the influence of climate on fire regimes. Hence, the management carried out by the indigenous brigades can be considered an important tool for fire management. In addition, demonstrates the importance of programs that integrate traditional indigenous knowledge with fire management policies, such as the Integrated Fire Management (IFM), to construct effective management strategies.
... Cerrado comprises the largest savanna in the neotropical region (Simon and Pennington 2012), and is characterised by the co-existence of the trees, shrubs, forbs, and grasses (Machida et al. 2021). The domain covers about 25% of the Brazilian territory (Durigan and Ratter 2016). However, this domain already has more than half of its area degraded (Klink and Machado 2005) due to monoculture cultivation and fire exclusion policies (Durigan and Ratter 2016). ...
... The domain covers about 25% of the Brazilian territory (Durigan and Ratter 2016). However, this domain already has more than half of its area degraded (Klink and Machado 2005) due to monoculture cultivation and fire exclusion policies (Durigan and Ratter 2016). Furthermore, the proximity of monoculture plantations to the natural arease.g. ...
Article
This study was carried out in a Cerrado (the largest savanna in the Neotropics) area where pine plantations, introduced in the 1970s, were removed by clear cutting of the trees and burning of the remaining material. After the removal and burning, some native shrub species resprouted. Since resprouting is dependent on buds that can be in the belowground bud-bearing (BBB) organs containing reserves, we selected three resprouting Myrtaceae species for analysis of morphology and anatomy of their BBB organs, to determine which compounds could be accumulated and to investigate the bud protection features. Standard histological techniques were used to analyse the BBB organs. The belowground bud bank at a depth of 10cm was determined. Nonstructural carbohydrates, total phenolics, and flavonoids were quantified on the roots. The large size of BBB organs suggest that these species were present before plantation establishment and survived plantation management treatments. All species produced a large number of axillary buds. All BBB organs exhibited significant lignification and stored starch and phenolic compounds in the parenchyma cells. The protective features and the storage of reserves associated with the bud-bank allowed the survival and subsequent resprouting of these species, contributing to the regeneration of this disturbed area.
... Another activity threatening the Cerrado is anthropic fires. As some authors claim that controlled and well-planned burnings help the ecosystem functionality and biodiversity, a policy that considers fire as part of the biome's dynamics is necessary (Durigan & Ratter, 2016;Hoffmann, 2013;Schmidt et al., 2016). Klink and Machado (2005) state that although the Cerrado is adapted to burning, uncontrolled and frequent use of this technique can lead to loss of nutrients, soil compaction, and erosion. ...
... According to Schmidt et al. (2016), the most common productive, commercial, and subsistence activities in Jalapão (agriculture, livestock, subsistence hunting, and handicrafts) depend on the use of fire. Durigan and Ratter (2016) argue that the lack of consistent policies for fire management and contention, which would be essential to maintain the structure, biodiversity, and ecosystem functionality, threats the Cerrado biome. Figures 3 and 4 show a large burned area in the studied period, although few regions had a recurrence of fire or were converted into anthropized areas, allowing the natural vegetation recovery (Table 4). ...
Article
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This study aims to map the changes in land use and land cover between 1970 and 2018, analyzing the influence of the protected area s (PAs) in the Cerrado biome, specifically in the area of the Jalapão Mosaic. Images from the Landsat 1-MSS, 5-TM, and 8-OLI satellites were used and processed in SPRING and ArcGIS software. The analyses were based on three approaches: (1) the boundary of the Jalapão Mosaic, (2) the PAs, and (3) a comparison between the PAs and their surroundings. The Jalapão Mosaic results demonstrated that 26% (≅ 8410 km²) of the area was burned, and 15.5% (4971 km²) was anthropized in at least one of the analyzed periods. Among the PAs, the Serra Geral do Tocantins Ecological Station (Integral Protection) presented the largest burned area (43.7% ≅ 3095 km²); however, there was no significant increase in the anthropized areas due to fire. Meanwhile, the anthropized areas in the Rio Preto and Serra da Tabatinga Environmental Protection Areas (Sustainable Use) increased by 27.5% and by 75%, respectively, due to agricultural expansion. By analyzing the two groups of PAs and their surroundings, it was observed that the loss of natural vegetation was restrained and fires were less intense in the Integral Protection Units; in the Sustainable Use Units, there was a significant increase in the anthropized areas. Furthermore, over 70% of the anthropized areas occurred in the surrounding areas, thus showing the importance of creating PAs.
... The decrease in natural wildfires in the Cerrado has been reported in several studies to be due to the lack of a fire policy (Durigan and Ratter, 2016;Durigan, 2020;Schmidt and Eloy, 2020). This process contributes to changes in the vegetation that have implications for biodiversity and the C cycle, for example, the increase of woody biomass (woody encroachment) (Durigan and Ratter, 2016;Pellegrini et al., 2016;Abreu et al., 2017). ...
... The decrease in natural wildfires in the Cerrado has been reported in several studies to be due to the lack of a fire policy (Durigan and Ratter, 2016;Durigan, 2020;Schmidt and Eloy, 2020). This process contributes to changes in the vegetation that have implications for biodiversity and the C cycle, for example, the increase of woody biomass (woody encroachment) (Durigan and Ratter, 2016;Pellegrini et al., 2016;Abreu et al., 2017). About 19% of the remaining natural vegetation in the Cerrado is exhibiting woody encroachment with a higher rate compared to other savanna biomes around the world (Stevens et al., 2017), and is likely related to anthropogenic landscape fragmentation which facilitates the suppression of natural wildfires . ...
Article
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The two major Brazilian biomes, the Amazonia and the Cerrado (savanna), are increasingly exposed to fires. The Amazonian Forest is a fire sensitive ecosystem where fires are a typically rare disturbance while the Cerrado is naturally fire-dependent. Human activities, such as landscape fragmentation and land-use management, have modified the fire regime of the Cerrado and introduced fire into the Amazonian Forest. There is limited understanding of the role of landscape fragmentation on fire occurrence in the Amazonia and Cerrado biomes. Due to differences in vegetation structure, composition, and land use characteristics in each biome, we hypothesize that the emerging burned area (BA) patterns will result from biome-specific fire responses to fragmentation. The aim of this study was to test the general relationship between BA, landscape fragmentation, and agricultural land in the Amazonia and the Cerrado biomes. To estimate the trends and status of landscape fragmentation a Forest Area Density (FAD) index was calculated based on the MapBiomas land cover dataset for both biomes between 2002 and 2018. BA fraction was analyzed within native vegetation against the FAD and agricultural land fraction. Our results showed an increase in landscape fragmentation across 16% of Amazonia and 15% of Cerrado. We identified an opposite relationship between BA fraction, and landscape fragmentation and agricultural fraction contrasting the two biomes. For Amazonia, both landscape fragmentation and agricultural fraction increased BA fraction due to an increase of human ignition activities. For the Cerrado, on the other hand, an increase in landscape fragmentation and agricultural fraction caused a decrease in BA fraction within the native vegetation. For both biomes, we found that during drought years BA increases whilst the divergent trends driven by fragmentation in the two contrasting global biomes is maintained. This understanding will be critical to informing the representation of fire dynamics in fire-enable Dynamic Global Vegetation Models and Earth System Models for climate projection and future ecosystem service provision.
... However, studies by Silva et al. (2011) report that sites with high intensity and frequent fires are negatively correlated to native Cactaceae populations, as they impair reproduction and survival in the environment. Bowman et al. (2009) andDurigan &Ratter (2015) also highlight the unknown effect of fire on the ecosystem processes mainly when it is not managed. Hence, more studies about how population dynamics of P. carambeiensis and entire ecosystems are influenced by wildfire occurrences are needed. ...
... However, studies by Silva et al. (2011) report that sites with high intensity and frequent fires are negatively correlated to native Cactaceae populations, as they impair reproduction and survival in the environment. Bowman et al. (2009) andDurigan &Ratter (2015) also highlight the unknown effect of fire on the ecosystem processes mainly when it is not managed. Hence, more studies about how population dynamics of P. carambeiensis and entire ecosystems are influenced by wildfire occurrences are needed. ...
Article
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Parodia carambeiensis is a rupicolous, small-sized species, with globose cladode and showy flowers, and is the only endemic Cactaceae species in Paraná State (Brazil). Changes in natural landscapes and fragmentation isolate populations, increasing their vulnerability to local extinctions. Our aim was to verify the spatial distribution of P. carambeiensis, reviewing its conservation status and main threats in the distribution area. Expeditions were carried out in the Campos Gerais region to record the abundance, density and spatial distribution of P. carambeiensis populations. Local landscape and climatic variables as well as the joint effect of these with geographical distance, were analyzed. Our findings highlighted that population density differs among the studied sites and was driven by distinct levels of anthropic threats such as livestock, tourism, wildfires and their proximity to highways, along with the climatic variables evaluated (temperature range and precipitation). The models jointly explained 56% of the variation in the population density, which was mostly influence by climatic factors. Parodia carambeiensis is currently classified as (LC) least concern, however, our results provide strong evidence in favor of updating its status to (EN) endangered due to the elevated extinction risk of natural populations.
... The IFM pilot program started in three protected areas in 2014, managed by national and state governments (Schmidt et al. 2016), and based on the Australian model ). The Cerrado-Jalapão pilot reflected a shift away from centralized fire suppression (Fidelis 2020;Moura et al. 2019), and researchers have encouraged a shift in public perceptions on fire in fire-prone settings (Durigan and Ratter 2016;. ...
... Ecologists recognize that zero-fire policies harm Cerrado ecosystems (Durigan and Ratter 2016). Abreu et al. (2017) estimated that fire suppression led to increased carbon stock at the expense of species richness; each 1% increase in carbon stock was associated with 0.98% decrease in savanna plant species richness. ...
Article
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Fire management influences the global carbon balance. This systematic literature review of proactive fire management programs as nature-based climate solutions synthesizes findings into four case studies to bring insight to these programs and their additional benefits. We review 136 papers, mostly from Australia, Brazil, Southern Africa, and the USA, reflecting the relevance of proactive fire management to savanna ecosystems. Four themes emerged: governance and policies; methodologies; reduced wildfire and GHG emissions; and co-benefits. Australia provides most literature on methodologies to account for greenhouse gas emissions abated. Australia and the USA focus on the social co-benefits, typically among Indigenous peoples. Biodiversity outcomes are largely discussed in Brazilian and African studies. Evidence of a shift to proactive fire management is documented in the case studies analyzed, but political, technical, and cultural barriers prevent further implementation at broader scales. ARTICLE HISTORY
... As informações de regimes atuais de incêndios quase não estão disponíveis para campos rupestres, ainda mais aqueles praticamente desprotegidos, ou seja, que carece de unidades de conservação (UC) (Figueira et al., 2016;Neves et al., 2018), como é o caso da região de Carrancas. Compreender o estado atual dessas áreas naturais remanescentes, considerando o histórico de incêndios com seus fatores determinantes do regime de fogo (Schmidt & Eloy, 2020), como a frequência, sazonalidade, as causas, os locais de ocorrência e a extensão queimada, podem ajudar a direcionar estratégias de manejo, prevenção e combate, dentro de uma política adequada e contextualizada de manejo integrado do fogo (MIF) (Durigan & Ratter, 2016). Na qual, gerentes de setores ambientais juntamente com atores sociais buscam o resgate das práticas tradicionais e aquelas mais eficientes de gerenciamento do fogo, em uma abordagem adaptativa (Berlinck & Batista, 2020;Eloy et al., 2019;Mistry et al., 2019). ...
... O padrão de distribuição de incêndios anual tem sido recorrente e preocupante, principalmente pelo aumento do uso indiscriminado e ilegal do fogo em áreas destinadas às atividades agropecuárias. Segundo Rodrigues (2016), o uso indiscriminado difere do manejo tradicional pela falta de planejamento e sem atender as condições ideais de queima, como ocorre em outras regiões do Cerrado (Strassburg et al., 2017;Durigan & Ratter, 2016), onde apresenta mais de 70% da área total queimada no Brasil (Araújo et al., 2012). Outros incêndios críticos têm sido registrados em UC do Cerrado, como nos Parques Nacionais da Serra da Canastra (Medeiros & Fiedler, 2004); da Chapada dos Veadeiros (Fiedler et al., 2006), e das Emas (França et al., 2007). ...
Article
Full-text available
Incêndios recorrentes representam o pior cenário de fogo para os ecossistemas naturais, pois resultam das alterações nos regimes de fogo sustentáveis dos ambientes. Informações sobre regimes atuais quase não estão disponíveis para os campos rupestres, ainda mais aqueles não protegidos legalmente, o que poderia direcionar melhores estratégias de gestão do fogo. Nosso objetivo foi descrever e analisar os regimes de fogo sem controle em remanescentes de campos rupestres, por meio de um estudo de caso no município de Carrancas, sul de Minas Gerais. Foram identificados e analisados os registros de incêndios e mapeadas as áreas consideradas pelos atores sociais locais como suscetíveis ao fogo. A coleta de dados se deu por meio do levantamento de fontes secundárias e a metodologia participativa de mapeamento comunitário realizada em um grupo focal. As informações foram sistematizadas em uma matriz histórica, e gerado um mapa de áreas suscetíveis. Foram identificados 43 registros de incêndios entre os anos de 2010 a 2019. Os campos nativos foram os mais atingidos, seguidos pelas áreas de preservação permanente. Nossos achados reforçam que regimes inadequados de fogo que evoluem para incêndios têm sido recorrentes em campos rupestres disjuntos, principalmente pelo aumento de ocorrências na estação seca tardia. Também, revelam que as áreas de serras são as mais suscetíveis ao fogo sob essas condições, os riscos à biodiversidade e aos serviços ecossistêmicos. É urgente assegurar um regime de fogo sustentável, reconhecendo o papel ecológico e sociocultural do fogo, e, assim, incorporar o manejo tradicional do fogo como prática conservacionista. Palavras-chave: Ecologia do fogo; mapeamento comunitário; Carrancas; impactos dos incêndios; manejo integrado do fogo.
... Fire acts as an ecological filter in the Cerrado, controlling the growth of forest species and favoring savanna species whose life-history strategies are adapted to higher temperatures and occurrence of fires, such as thicker barks, bud protection (Pausas et al., 2018), flowering stimulated by temperature and smoke , and resprouting (Zupo et al., 2021). In addition to degradation by agricultural activities, another factor that contributes to changes in vegetation structure is woody plant encroachment, partially caused by the way that these remaining native areas are protected (Durigan and Ratter, 2016). Cerrado is not specifically mentioned in the environmental section of Brazilian Constitution and the main conservation policies are focused on forest recovery and fire suppression, neglecting intrinsic factors such as dominance of grasses and the role of fire in maintenance of high endemism and diversity (Bond and Keeley, 2005;Durigan and Ratter, 2016;Pausas et al., 2006). ...
... In addition to degradation by agricultural activities, another factor that contributes to changes in vegetation structure is woody plant encroachment, partially caused by the way that these remaining native areas are protected (Durigan and Ratter, 2016). Cerrado is not specifically mentioned in the environmental section of Brazilian Constitution and the main conservation policies are focused on forest recovery and fire suppression, neglecting intrinsic factors such as dominance of grasses and the role of fire in maintenance of high endemism and diversity (Bond and Keeley, 2005;Durigan and Ratter, 2016;Pausas et al., 2006). Because the Cerrado flora is adapted do harsh environmental conditions (i.e. ...
Article
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 ≥ 5cm) and juvenile (trees with diameter at ground level < 5cm) 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 management is probably required for the long-term conservation of open physiognomies of the neotropical savannas known as Cerrado (Durigan & Ratter, 2016), the second largest vegetation domain in South America (Oliveira-Filho & Ratter, 2006), with high levels of endemism, and one of the hotspots for global conservation (Myers et al., 2000). Despite its importance, the Cerrado has been rapidly degraded (Strassburg et al., 2017). ...
... Like other savannas, Cerrado is subject to sporadic and natural occurrence of fires (Coutinho, 1981;Ramos-Neto & Pivello, 2000), and depend on the fire regime to maintain the structure, biodiversity and functioning (Abreu et al., 2017;Durigan & Ratter, 2006). Despite these observations, Brazil still has no consistent fire policy, which leverages the use of prescribed fire as a tool for savanna conservation (Durigan & Ratter, 2016;Pivello et al., 2021). There is a perception of the general public that fire is detrimental to the fauna, and the handful of studies addressing this issue call for caution in the recommendation to use prescribed fire as a management tool (but see Durigan et al., 2020 and references therein). ...
Article
Seed dispersal and predation by animals often drive plant regeneration. In tropical savannas, such as the Cerrado of Brazil, fire is also a key process in ecosystem dynamics, consuming the lower vegetation strata and killing wildlife, but how fire affects seed-animal interactions is virtually unknown. We investigated the effects of prescribed fires on the removal of diaspores from Miconia rubiginosa and sunflower Helianthus annuus in Cerrado from southeast Brazil. Using plots burned one month or one year before sampling and unburned controls, we assessed the effect of prescribed fire on microhabitat structure and diaspore removal by vertebrates and ants. Covered microhabitats experienced higher seed removal by vertebrates than open microhabitats, but microhabitat features did not influence seed removal by ants. Prescribed fire did not change the total amount of seed removal, and ants were responsible for most removals in burned and control plots. However, fire increased the importance of ants as agents of removal compared to vertebrates. These changes were probably mediated by changes in microhabitat cover. It is likely that species, whose seeds are often preyed upon by vertebrates, benefit from fire to escape predation, while the opposite would be true for those removed by granivorous ants. By changing microhabitats composition and frequency of seed removal by different agents, fire may create pulses of opportunities for certain plant species to increase their populations and enlarge their spatial distribution, while constraining others. However, how different fire intensities and frequencies influence seed fate of different species is still to be investigated. Abstract in Portuguese is available with online material.
... Climate change mitigation and biodiversity conservation efforts across the world require an understanding of wildfire dynamics (Bowman et al., 2013;Lehmann et al., 2014). Tropical Savanna ecosystems are generally fire-adapted (Simon et al., 2009;Hoffmann et al., 2012;Durigan and Ratter, 2016), but human activities have affected fire regimes and landscape characteristics (Hantson et al., 2015;Andela et al., 2017;Andela et al., 2018;Rosan et al., 2019;Durigan et al., 2020). Fire dynamics in tropical savannas depend, among other factors, on the vegetation structure and accumulated fuel loads (combustible contents) (Sandberg et al., 2001;Chuvieco et al., 2003;Keane et al., 2013). ...
... It has been rapidly converted to crop and pasturelands and less than half of its original vegetation cover remains (Strassburg et al., 2017). This native vegetation, however, has been severely impacted by humanmediated shifts in fire regimes and widespread invasion of fire-prone African fodder grasses (Durigan and Ratter, 2016). Our study sites are located in the Serra do Cipó National Park (SCNPK), Chapada dos Veadeiros National Park (CVNPK), Paraopebas National Forest (PNF) and University of São João Del-Reis Forest (UFSJ) (Fig. 1). ...
Article
Quantifying fuel load over large areas is essential to support integrated fire management initiatives in fire-prone regions to preserve carbon stock, biodiversity and ecosystem functioning. It also allows a better understanding of global climate regulation as a potential carbon sink or source. Large area assessments usually require data from spaceborne remote sensors, but most of them cannot measure the vertical variability of vegetation structure, which is required for accurately measuring fuel loads and defining management interventions. The recently launched NASA's Global Ecosystem Dynamics Investigation (GEDI) full-waveform lidar sensor holds potential to meet this demand. However, its capability for estimating fuel load has yet not been evaluated. In this study, we developed a novel framework and tested machine learning models for predicting multi-layer fuel load in the Brazilian tropical savanna (i.e., Cerrado biome) using GEDI data. First, lidar data were collected using an unnamed aerial vehicle (UAV). The flights were conducted over selected sample plots in distinct Cerrado vegetation formations (i.e., grassland, savanna, forest) where field measurements were conducted to determine the load of surface, herbaceous, shrubs and small trees, woody fuels and the total fuel load. Subsequently, GEDI-like full-waveforms were simulated from the high-density UAV-lidar 3-D point clouds from which vegetation structure metrics were calculated and correlated to field-derived fuel load components using Random Forest models. From these models, we generate fuel load maps for the entire Cerrado using all on-orbit available GEDI data. Overall, the models had better performance for woody fuels and total fuel loads (R² = 0.88 and 0.71, respectively). For components at the lower stratum, models had moderate to low performance (R² between 0.15 and 0.46) but still showed reliable results. The presented framework can be extended to other fire-prone regions where accurate measurements of fuel components are needed. We hope this study will contribute to the expansion of spaceborne lidar applications for integrated fire management activities and supporting carbon monitoring initiatives in tropical savannas worldwide.
... The chief argument used by Brazilian environmental organizations is that raising cattle, with its concomitant reliance on the use of fire to manage pastures, is not compatible with conservation (Lúcio, 2013). This view prevails in Cerrado biome, despite evidence supporting the role of fire management in maintaining the savanna and preventing uncontrolled and destructive fires (Durigan & Ratter, 2016). ...
... There is evidence suggesting that savanna landscapes formed by a mosaic of unburned and burned patches at different intervals may help generate more diverse landscapes with higher species diversity (McGregor et al., 2010;Ramos-Neto & Pivello, 2000). A critical distinction therefore is between the effects of smaller, more localized and carefully managed fires and those of much hotter, intense, large-scale fires resulting from, among other things, indiscriminate fire suppression policies (Durigan & Ratter, 2016). ...
Article
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We examine the ongoing transformation of the livestock raising component of a complex agrosilvopastoral management system associated with the Geraizeiro of northern Minas Gerais state, Brazil. Increasing droughts and regional climate change, associated with large-scale corporate enclosures of upland rangelands and conversion to eucalyptus plantations for industrial charcoal production have undermined solta, a customary form of extensive cattle raising and centerpiece of Geraizeiro lifeways. In response, farmers are adapting and transforming another, more intense form of livestock raising associated with managed agroforestry in lower-lying areas, manga. Using a social-ecological systems approach and drawing on extensive interviews and ecological inventories, we consider such changes within the overall integrity of the system, suggesting the need to reconsider the role of the Geraizeiros and their use of cattle and fire as a potentially useful tool in reconciling livelihoods and conservation, particularly amidst accelerating social and environmental change and the concomitant threats to the savanna biocultural biome.
... The Cerrado (Brazilian Savanna) is the second-largest biome in Brazil, after the Amazonian rainforest, and the largest one in South America. It accounts for 25 % of its national territory (RIBEIRO; WALTER, 1998;CARVALHO et al., 2009;DURIGAN;RATTER, 2016). The Cerrado is considered a hotspot due to its enormous biodiversity, high degree of endemism, and high susceptibility to human activities (MITTERMEIER et al., 2005;STRASSBURG et al., 2017). ...
... The Cerrado (Brazilian Savanna) is the second-largest biome in Brazil, after the Amazonian rainforest, and the largest one in South America. It accounts for 25 % of its national territory (RIBEIRO; WALTER, 1998;CARVALHO et al., 2009;DURIGAN;RATTER, 2016). The Cerrado is considered a hotspot due to its enormous biodiversity, high degree of endemism, and high susceptibility to human activities (MITTERMEIER et al., 2005;STRASSBURG et al., 2017). ...
Article
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The Cerrado is the second largest biome in South America and due to its great species, richness, and environmental degradation, is considered a biodiversity hotspot. Fires in Cerrado can occur both naturally and through anthropic influence. However, due to the latter, the occurrence of fires has been increasingly frequent, as well as its impact on biotic communities. Ants' colonies are widely used in studies of environmental impacts because of their responsiveness to environmental changes and easiness for their data to be analyzed. Here, the structure of the ants' community in Cerrado environments at different areas post-fire times (two and four months, and a control area) in Itumirim, Minas Gerais, Brazil, was evaluated. Attractive baits were used as sampling methods, and found 48 species of ants belonging to 18 genera. Species richness was the same in all areas, showing that both two and four months after the fire occurrences seem to be enough to recover the ant population of these areas. Regarding ant composition, there were important differences, especially between the control area and the four months post-fire area. Moreover, vegetal biomass and vegetation covers only influenced ant composition. Here, it was found that species composition seems to be a better indicator of the responses of ant communities to post-fire effects, and can be used as a tool in monitoring programs.
... One of the characteristics of the vegetation formations of Pantanal is the presence of monodominant stands (>50 % of individuals belonging to a single species), frequently associated with high levels of inundation (Manrique-Pineda et al., 2021). The Brazilian Cerrado comprises a mosaic of vegetation types forming a structural gradient from grasslands through savanna woodland to forests (Durigan and Ratter, 2015). Cerrado is highly flammable in the dry season, like the savannas of other regions of the world (Durigan and Ratter, 2015;Fidelis et al., 2018). ...
... The Brazilian Cerrado comprises a mosaic of vegetation types forming a structural gradient from grasslands through savanna woodland to forests (Durigan and Ratter, 2015). Cerrado is highly flammable in the dry season, like the savannas of other regions of the world (Durigan and Ratter, 2015;Fidelis et al., 2018). The Atlantic Forest of MS comprises deciduous and semideciduous seasonal forests (medium and large trees, not widely spaced) with high fertility soils. ...
Article
The trade-off between conservation of natural resources and agribusiness expansion is a constant challenge in Brazil. The fires used to promote agricultural expansion increased in the last decades. While studies linking annual fire occurrence and rainfall seasonality are common, the relationship between fires, land use, and land cover remains understudied. Here, we investigated the frequency of the fires and performed a trend analysis for monthly, seasonal, and annual fires in three different biomes: Cerrado, Pantanal, and Atlantic Forest. We used burned area and integrated models in distinct scales (interannual, intraseasonal, and monthly) using Probability Density Functions (PDFs). The best fitting was found for Generalized Extreme Values (GEV) distribution at all three biomes from the several PDFs tested. We found the most fire in the Pantanal (wetlands), followed by Cerrado (Brazilian Savanna) and Atlantic Forest (Semideciduous Forest). Our findings indicated that land use and land cover trends changed over the years. There was a strong correlation between fire and agricultural areas, with increasing trends pointing to land conversion to agricultural areas in all biomes. The high probability of fire indicates that expanding agricultural areas through the conversion of natural biomes impacts several natural ecosystems, transforming land cover and land use. This land conversion is promoting more fires each year.
... The occurrence of natural burning is essential for maintaining diversity and structure of cerrado, especially the Cerrado stricto sensu (Lehmann et al. 2014;Pellegrini et al. 2016). However, fire-handling practices in the conservation of APPs and cerrado conservation units are not yet adopted (Durigan and Ratter 2016). In addition, biome fragmentation may be hindering the natural spread of fire in this biome (Abreu et al. 2017). ...
... obtained throughout evolution(Durigan and Ratter 2016). As a result, possible changes caused by earthworm extraction in soil characteristics and fire frequency can be prejudicial to the conservation of the Cerrado's natural vegetation.Considering these risks caused by giant earthworm extraction in the Cerrado in the conservation of natural characteristics and its biodiversity, our objective in this study was: (1) to evaluate if there are changes in soil characteristics in areas with intense giant earthworms extraction; (2) if the earthworm extraction activities increase the intensity of the fire; and (3) whether this disturbance alters plant composition and species richness in remnants of Cerrrado stricto sensu. ...
... However, humans have been modifying the natural fire regimes for over 4000 years: from before European colonization, when indigenous peoples of Cerrado used fire for several activities (but practiced refined fire management methods), to the current use of fire in the region, mainly for agricultural practices and cattle ranching (Pivello 2011). Thus, even though fires are key in determining species composition (Loiola et al. 2010;Silva et al. 2013;Pilon et al. 2021) and plant reproductive success (Ara ujo et al. 2013;Pilon et al. 2018;Zirondi et al. 2021), its indiscriminate use, primarily for pasture management, threatens the Cerrado and has ultimately altered Cerrado fire regimes (Durigan & Ratter 2016;Schmidt & Eloy 2020). On the one hand, human activities have caused fires to become more frequent and occur mainly during the dry season; on the other hand, such misuse of fire has led to a policy of fire suppression in many areas (Durigan 2020;Schmidt & Eloy 2020;Barradas & Ribeiro 2021). ...
... Conversely, frequent fires can negatively affect tree and shrub biomass recovery (Gomes et al. 2020a), favor the invasion of exotic grass species (Gorgone-Barbosa et al. 2016), and increase carbon emissions (Gomes et al. 2020b). Thus, both extremes can be detrimental for the conservation of Cerrado ecosystems, stressing the need for a consistent national fire management policy (Durigan & Ratter 2016). Although the first steps to implement an integrated fire management plan have been taken (Schmidt et al. 2018;Schmidt & Eloy 2020;Barradas & Ribeiro 2021), there are still major gaps in our understanding of how altered fire regimes affect fire parameters and thus impact vegetation (Gomes et al. 2018;McLauchlan et al. 2020). ...
Article
Fire is a main disturbance structuring vegetation worldwide, but few studies have addressed differences in time since last fire and its relationship to fuel load characteristics and fire behavior in Neotropical savan-nas. We aimed to investigate fire behavior in a Cerrado open savanna of Central Brazil by conducting prescribed fires in areas with different fire-free intervals: one year (FI-1), two years (FI-2), and four years (FI-4). Specifically , we evaluated (1) the amount of live, dead, and total biomass (components of the fuel load); (2) fire behavior , including fire temperatures in three different heights (1 cm belowground, on the soil surface, and 50 cm aboveground), fire duration, residence time, fire intensity, rate of spread, and flame height; and (3) the relationship between soil heating, fuels, and fire by identifying the most important parameters driving soil heating. Total and dead fuel loads were greater in areas with longer fire-free intervals in comparison with areas burned the previous year, with the greatest increment to the fuel bed occurring in the first two years after fire. Greater fuel loads (consequently greater dead fuel loads) resulted in differences in belowground soil heating (-1 cm), where temperatures varied from 39 to 82°C in FI-2 plots and from 40 to 131°C in FI-4 plots; in FI-1 plots temperatures belowground varied from 29 to 68°C. Temperatures on the soil surface and 50 cm aboveground were also greater in plots with longer fire-free intervals, reaching over 400°C on the soil surface and exceeding 500°C 50 cm aboveground. Finally, amount of dead fuel was the best predictor of belowground soil heating, highlighting the importance of fuel loads, which is a key factor to be monitored in fire management plans of Cerrado open savannas.
... The Cerrado (Brazilian Savanna) is the second-largest biome in Brazil, after the Amazonian rainforest, and the largest one in South America. It accounts for 25 % of its national territory (RIBEIRO; WALTER, 1998;CARVALHO et al., 2009;DURIGAN;RATTER, 2016). The Cerrado is considered a hotspot due to its enormous biodiversity, high degree of endemism, and high susceptibility to human activities (MITTERMEIER et al., 2005;STRASSBURG et al., 2017). ...
... The Cerrado (Brazilian Savanna) is the second-largest biome in Brazil, after the Amazonian rainforest, and the largest one in South America. It accounts for 25 % of its national territory (RIBEIRO; WALTER, 1998;CARVALHO et al., 2009;DURIGAN;RATTER, 2016). The Cerrado is considered a hotspot due to its enormous biodiversity, high degree of endemism, and high susceptibility to human activities (MITTERMEIER et al., 2005;STRASSBURG et al., 2017). ...
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The Cerrado is the second largest biome in South America and due to its great species, richness, and environmental degradation, is considered a biodiversity hotspot. Fires in Cerrado can occur both naturally and through anthropic influence. However, due to the latter, the occurrence of fires has been increasingly frequent, as well as its impact on biotic communities. Ants' colonies are widely used in studies of environmental impacts because of their responsiveness to environmental changes and easiness for their data to be analyzed. Here, the structure of the ants' community in Cerrado environments at different areas post-fire times (two and four months, and a control area) in Itumirim, Minas Gerais, Brazil, was evaluated. Attractive baits were used as sampling methods, and found 48 species of ants belonging to 18 genera. Species richness was the same in all areas, showing that both two and four months after the fire occurrences seem to be enough to recover the ant population of these areas. Regarding ant composition, there were important differences, especially between the control area and the four months post-fire area. Moreover, vegetal biomass and vegetation covers only influenced ant composition. Here, it was found that species composition seems to be a better indicator of the responses of ant communities to post-fire effects, and can be used as a tool in monitoring programs.
... It has transformative effects on nearly all ecosystem properties, including microclimate, plant and animal communities and disturbance regimes (Parr et al., 2014). Fire suppression, a misguided conservation policy applied to the Brazilian savanna for decades (Durigan & Ratter, 2016), has allowed woody encroachment and fast replacement of savanna specialists by forest species. We here document woody encroachment starting from new or existing sparse trees in open areas. ...
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Fulltext at: https://besjournals.onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2664.13994 1. Woody encroachment into grassy biomes is a global phenomenon, often resulting in a nearly complete turnover of species, with savanna specialists being replaced by forest‐adapted species. Understanding the mechanisms involved in this change is important for devising strategies for managing savannas. 2. We examined how isolated trees favor woody encroachment and species turnover by overcoming dispersal limitation and environmental filtering. In a savanna released from fire in southeastern Brazil (Cerrado) we sampled woody plants establishing under 40 tree canopies and in paired treeless plots. These trees comprised eight species selected for habitat preference (savanna or forest) and dispersal syndrome (bird‐dispersed or not). We recorded dimensions of each tree, dispersal syndrome and habitat preference of recruits, and quantified the physical environment within each plot, aiming at a mechanistic understanding of woody encroachment. 3. We found clear evidence that isolated trees cause nucleation and drive changes in functional composition of savanna. Effectiveness as nucleator differed among species, but was unrelated to their functional guilds (habitat preference or dispersal syndrome). Density of saplings in nuclei was partially explained by soil moisture (+), daily temperature amplitude (‐), and sum of bases (‐). 4. Our results indicate that isolated trees act first as perches, strongly favoring bird‐dispersed species. They then act as nurse trees, considerably changing the environment in favor of forest‐adapted recruits. In the long term, as the nuclei expand and merge, savanna specialists tend to disappear and the savanna turns into a low‐diversity forest. 5. Synthesis and applications: Fire suppression has allowed the nucleation process and consequently the woody encroachment and fast replacement of savanna specialists by forest species in the Cerrado. By elucidating the mechanisms behind woody encroachment, we recommend using prescribed fires to burn forest seedlings and to reduce tree canopy size wherever the management goal is to maintain the typical savanna structure and composition.
... In fact, the SBES was created with the goal to protect the open formations of the southern Cerrado, but 30 years of fire suppression are probably the main cause of the local woody encroachment and the resulting changes in biodiversity (Abreu et al., 2017(Abreu et al., , 2021. Fire management is considered a key tool to maintain open savannas and its associated diversity, and the current fire experiments at SBES so far demonstrate no loss in small mammal diversity with prescribed fire (Durigan and Ratter, 2016;Durigan et al., 2020). Without active management of the landscape to keep open habitats, the long-term maintenance of the openhabitat specialists (with special attention to the rarest ones) will give place to an increasing replacement by forest specialists and habitat generalists in the SBES small mammal community and in other remnants in the southern portion of the Cerrado. ...
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Years of fire suppression, decreases in herbivores, and global climate change have led to shifts in savannas worldwide. Natural open vegetation such as grasslands and shrublands is increasing in wood density, but the effects for small mammals are not well understood. While most of the mammal studies from the Brazilian Cerrado are concentrated in the core area of this large Neotropical savanna, its southern portions are suffering from biome shifting through woody encroachment. Herein, we surveyed a small mammal community from the southeastern boundary of Cerrado (Santa Bárbara Ecological Station) and evaluated the micro and macro environmental variables shaping community structure in order to investigate how the woody encroachment in the last 15 years may have influenced this assemblage. We recorded 17 species of marsupials and rodents along five distinct habitats in a gradient from grasslands to woodlands. Although richness was not affected by microhabitat variables, total and relative abundance varied according to habitat type and in relation to herbaceous, shrub, and tree density. Rodents such as Calomys tener and Clyomys laticeps were positively affected by increasing herb cover, Cerradomys scotti and Oligoryzomys nigripes by shrub cover, while the marsupial Didelphis albiventris had higher association with increasing tree cover. We detected an increase of 27.4% in vegetation density (EVI) between 2003 and 2018 in our study site, and this woody encroachment negatively affected the abundance of some small mammals. The open-area specialists Cryptonanus chacoensis and C. scotti had a decrease in abundance, while D. albiventris and O. nigripes were favored by woody encroachment. Our data suggest that woody encroachment is shifting community composition: small mammals often associated with grasslands and open savannas are likely to be negatively affected by woody encroachment; while species that rely on tree-covered habitats are likely to benefit from an increasing woody landscape. Therefore, forest-dwellers are gradually replacing open-vegetation inhabitants. Active management of open formations (e.g., with prescribed burning) may be needed to maintain Cerrado biodiversity, especially considering the open-area endemics.
... Fire has been used as a management tool by farmers on grassdominated lands for centuries in Brazil ( Cochrane, 2009;Mistry et al., 2005;Pivello, 2011 ). At the same time, fire is subject to much debate in science and society ( Durigan and Ratter, 2016;Mistry et al., 2019 ) with regard to the increase of wildfire risk, preservation of natural grassland ecosystems and the sustainability of pasture management. Fire practices are usually carried out during the winter or dry season and are based on land managers' observations of vegetation conditions ( Mistry, 1998;Sorrensen, 20 0 0;van der Werf et al., 2008 ). ...
Article
Fire is widely used by farmers in Brazil during the winter, or the dry season, to remove accumulated dead pasture biomass. These practices have substantial impacts on vegetation, soil nutrients and carbon emissions. However, they are rarely represented within process-based fire models embedded within Dynamic Global Vegetation Models (DGVM). We developed an algorithm named Chalumeau to estimate the expected burning dates from daily precipitation or temperature depending on the seasonality type. By coupling with a fire module from a DGVM, Chalumeau enables the ignition of fire as an essential part of modelling fire practices. The burning dates are evaluated by comparing against observed fire dates on pasture. From these estimated dates, we extract the timing strategies of ranchers, which vary regionally within Brazil. This study confirms that climatic conditions are the main trigger for farmers decisions to set fire and shows the different burning strategies across Brazil.
... Esto implica que, aunque hubo una consistencia en la riqueza de especies en la formación sabánica, la composición de especies varió significativamente entre cada transecto. A partir de la comparación de composición de especies hecha en este análisis, se corrobora la disimilitud florística típica entre las formaciones forestales y sabánicas del Cerrado en el área de estudio (3,36) , derivada de la combinación de la estacionalidad de las lluvias, las condiciones del suelo, el régimen del fuego y el factor de tolerancia a la sombra de las plantas (3,(41)(42)(43)(44) , lo que sugiere un buen estado de conservación del área protegida. No obstante, debido al tipo de evaluación que se realizó, y dado que los indicadores analizados no se contrastaron con factores como la frecuencia de la perturbación ocasionada por el fuego y la presencia de plantas exóticas con potencial de invasión observadas, se recomienda monitorear de forma continua el área, y establecer investigaciones que exploren estos elementos, de manera a avanzar hacia una mejor comprensión de la dinámica vegetacional local y una mejor valoración de su biodiversidad. ...
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El objetivo de este estudio fue realizar una evaluación ecológica rápida de la flora nativa de la formación forestal y sabánica del Cerrado Aguará Ñu, Reserva Natural del Bosque Mbaracayú de Paraguay, determinando la riqueza de especies y las diferencias de composición entre las mismas, de manera a complementar los levantamientos florísticos ya existentes. Se registró in situ la flora vascular nativa del Cerrado mediante diez transectos de 50 m x 2 m (1000 m2) en cada formación vegetal (forestal y sabánica). Se obtuvo un total de 171 especies en 61 familias. La formación sabánica presentó la mayor riqueza de especies en relación a la formación forestal, con 106 especies en 40 familias y 81 especies en 40 familias, respectivamente. Las especies más frecuentes en la formación sabánica fueron Axonopus cfr. siccus (Nees) Kuhlm., Butia paraguayensis (Barb. Rodr.) L.H. Bailey, Duguetia furfuracea (A. St.-Hil.) Benth. & Hook. f., Campomanesia adamantium (Cambess.) O. Berg, y Pradosia brevipes (Pierre) T.D. Penn. En cuanto a la formación forestal, las especies más frecuentes fueron Copaifera langsdorffii Desf. var. langsdorfii, Didymopanax morototoni (Aubl.) Decne. & Planch., Protium heptaphyllum (Aubl.) Marchand, y Vochysia tucanorum C. Mart. Ambas formaciones vegetales sólo compartieron 14 especies de plantas. La familia Fabaceae registró el mayor número de especies. Por otro lado, se evidenció la disimilitud florística típica entre las formaciones forestales y sabánicas del Cerrado en el área de estudio, lo que sugiere un buen estado de conservación del área protegida. No obstante, dadas las características y limitaciones de la evaluación ecológica rápida, se recomienda seguir monitoreando el área de manera a avanzar hacia una mejor comprensión de la dinámica vegetacional local y una mejor valoración de su biodiversidad.
... For example, a higher priority can be assigned to areas that concentrate high numbers of rare species, especially species with restricted geographic range, ecoregion specialists, and small populations (e.g., Prendergast et al., 1993). Additionally, we also encourage analysis of the vulnerability of rare species due to changes in different drivers which could affect the savanna plant diversity such as changes in fires and climate (Durigan and Ratter, 2016;Maciel et al., 2021). ...
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The interest in quantifying rare species has been increasing, but less attention has been paid to analysing their conservation status. Here, we used the Rabinowitz method based on geographical range, habitat specificity and population size to classify 2,203 tree species of South American savannas (SAS). We considered species with narrow (stenochoric) or wide (eurychoric) geographic range respectively occurring in up to 10% or over of the latitudinal belts in the SAS, specialist (stenoecious) or generalist (euryoecious) species occurring in one or more ecoregions, respectively, and locally scarce or abundant populations of species with low or high numbers of records within a grid cell of 1° latitude by 1° longitude, respectively. We then quantified species which only occur inside protected areas (PAs), in and outside PAs, or only outside PAs. Of the 2,203 species, 49.25% were rare, 40.35% stenochoric, 14.12% stenoecious and 56.15% had a scarce population. The Cerrado (433) followed by Caatinga (259), Campos Rupestres montane savanna (256), Bahia interior forests (189) and Guiana savanna (154) had the highest number of rare species. Only 6.44% species only occurred inside PAs, 83.79% in and outside PAs and 9.75% only outside PAs. Unprotected species are mostly geographically restricted with ecoregion specialists, and have small population sizes. The number of protected species are is positively correlated with the number of records within them. The establishment of PAs should focus on both core and disjunct savannas to encompass all ecoregions in order to ensure the conservation of species and the range of evolutionary processes in SAS.
... Disturbance suppression is a threat to open ecosystems such as grasslands (Abreu et al., 2017;Overbeck et al., 2015), but fire is seldom considered as a management tool in Brazil (Pillar et al., 2010). Detailed protocols to guide the use of fire in management are still lacking for Brazilian non-forest ecosystems (Durigan and Ratter, 2016;Overbeck et al., 2018). Therefore, it is imperative that scientists, decision-makers, and managers of protected areas focus their complementary knowledge and experiences towards this end. ...
Article
Fire is among the major forces shaping patterns in nature. Although sometimes it is only acknowledged for its destructive power, it was one of the evolutionary drivers that produced present-day species and biome distributions, being inextricably linked to fire-prone ecosystems such as grasslands. Knowing how fire influences grassland biodiversity is therefore fundamental to conserve it. Here we analyzed the taxonomic and functional structure of grassland plant communities from Southern Brazil under different post-fire successional stages. We sampled 12 sites that were fire-suppressed for varying amounts of time (3 to 300 months), categorized in three post-fire stages: freshly-burnt (FB), intermediate-burnt (IB), and old-burnt (OB). We compared these stages regarding taxonomic composition, species richness, diversity (partitioned in different spatial components), and functional composition (based on plant life forms and metabolism). We sampled 307 plant species from 52 families. Species richness was lower in the OB stage, and did not differ between FB and IB stages. Species composition was markedly different between stages. Forty-five percent of the sampled species were exclusive to one post-fire stage, and only 23% were shared among them. Old-burnt sites share only up to 5% species with other stages and concentrated most of the trees and tussocks. Because long-term fire suppression allowed for the entry of different floristic elements in the community, taxonomic diversity (beta and gamma levels) was higher in old-burnt sites. Our results provide empirical evidence that fire suppression is likely to shift the fire-prone grasslands from Southern Brazil towards different ecosystem states, although whether this process is leading towards a closed forest system or to a different system with coexisting grassland and forest elements, remains an open question. The sharp floristic differences and exclusive species in the different post-fire stages reinforce the need to include fire in the conservation framework for fire-prone grasslands.
... All rights reserved left (Nowacki & Abrams, 2015). Fire suppression in nature reserves in the Brazilian cerrado caused the loss of the rich sun-loving cerrado plant species, especially the herbaceous layer, and their replacement by shade-tolerant trees and shrubs (Durigan and Ratter 2016;Abreu et al., 2017). And conifer plantations in old growth grasslands have led to the loss of the rich forb flora which has failed to re-colonise areas many decades after the forests were felled (Veldman et al., 2015). ...
... This research sheds new light on the magnitude of impacts of Indigenous people on fire regimes, underscoring the radical changes in fire regimes that can emerge when Indigenous people are displaced from their land. In doing so, we contribute to a building global narrative of the importance of Indigenous fire around the world, e.g., in South America (Nepstad et al. 2006;Pivello 2011;Durigan et al. 2016), North America (Liebmann et al. 2016), Mali (Laris 2002), and Australia (Bliege Bird et al. 2008Trauernicht et al. 2015). We highlight that Indigenous fire regimes work to craft ecosystems into states that are profoundly different from the ecosystems without their presence (Bliege Bird and Nimmo 2018), separating a transition from fine scale fire mosaics to landscapes with homogenised fire histories. ...
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ContextIn many regions of the world, Indigenous people continue to shape landscape patterns using fire. Some studies show that Indigenous fire regimes create a diverse “visible mosaic” of time-since-fire ages. Less is known about the underlying, cumulative spatiotemporal patterns of fires that are hidden beneath visible fire scars—termed the “invisible fire mosaic”—despite its role in shaping biota in fire-prone landscapes.Objectives We investigated how distance from Indigenous communities affects landscape patterns, focusing on aspects of the visible (i.e., time-since-fire diversity and maximum landscape area burnt) and invisible (i.e., number of years burnt, diversity of fire frequency patches, and number of unique fire histories) fire mosaic.Methods We quantified fire histories for 450 landscapes across Western Australia. We calculated the distance of each landscape to the nearest Indigenous community (a proxy for the intensity of human landscape use) and used regression models to investigate how distance influenced the properties of the visible and invisible fire mosaic.ResultsLandscapes near Indigenous communities experienced more frequent fire, had higher time-since-fire diversity, higher diversity of fire frequency patches, and a greater number of unique combinations of fire histories (seasons, interval lengths, and time-since-fire ages). Pyrodiversity was negatively related to the maximum area burnt, supporting the notion that Indigenous burning limits fire size.Conclusions Indigenous burning creates distinctive visible and invisible fire mosaics which dwarf the pyrodiversity of more distant areas, thereby potentially crafting ecosystem states that profoundly differ from those without human presence.
... A savana brasileira compreende um mosaico de diferentes tipos de vegetações, algumas adaptadas ao fogo como a área de savana e outras sensíveis a este como as matas ciliares, sendo que os incêndios florestais naturais moldaram as paisagens do bioma Cerrado por milhões de anos (WALTER; RIBEIRO, 2010;DURIGAN;RATTTER, 2016). Os incêndios florestais de maiores proporções (> 50.000 ha) geralmente ocorrem no final da estação seca a cada 2 a 5 anos na maioria das unidades de conservação do bioma Cerrado, ameaçando comunidades locais e infraestrutura, bem como causando perdas econômicas e ambientais (FRANÇA, 2010). ...
Article
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A realização de queimas prescritas, com diferentes objetivos de gestão e manejo, vem sendo aplicada mais frequentemente em áreas protegidas. Com o intuito de compreender o efeito do fogo, o presente trabalho teve como objetivo avaliar a abundância e a diversidade dos microrganismos fúngicos em resposta ao uso do fogo e incêndios florestais. As amostras de solo anterior e após a queimada foram coletadas, sendo os fungos isolados pelo método de plaqueamento, posteriormente quantificados por meio da contagem das unidades formadoras de colônia (UFC g-1) e identificados ao nível de gênero. A média de UFC g-1 não apresentou diferença significativa entre os regimes de fogo avaliados, no entanto houve diferença significativa (p0,05) para diversidade, tendo os dois anos de incêndios ocasionado menor diversidade de gênero. Os gêneros Aspergillus e Penicillium estiveram presentes em todas as áreas amostradas, com maiores valores de UFC g-1,enquanto os gêneros Mucor e Rhizopus apresentaram os menores valores. A média de unidade formadora de colônia (UFC g-1) e diversidade antes e após a queima prescrita diferiram estatisticamente (p0,05), sendo que a média de UFC g-1 teve redução e a diversidade apresentou aumento após a passagem do fogo em todas as áreas avaliadas. A maior redução da média de UFC g-1 ocorreu para o mês de julho. Os valores de coeficientes de correlação de Pearson obtidos demonstraram correlação negativa significativa entre a média de UFC g-1, a diversidade e a temperatura (r=0,70; r=-0,98 e p0,05). A variável diversidade apresentou correlação negativa com a temperatura, precipitação e umidade relativa do ar (r=-0,56; r=-0,86; r=-0,86 e p0,05), indicando que houve influência direta destas variáveis na abundância e diversidade dos fungos do solo. Os parâmetros do solo (alumínio, acidez trocável, capacidade de troca de cátions, cálcio, magnésio, cálcio e magnésio, fósforo, pH, saturação por base e de alumínio) possuem relação direta com os fungos do solo.
... For instance, most of the fires associated with deforestation occur in the same year or the subsequent year (Alencar et al., 2020;Aragão et al., 2008;Silveira et al., 2020), while agricultural fires occur yearly or bi-annually (Chen et al., 2013;Eloy et al., 2018;Fidelis et al., 2018;Jakimow et al., 2018). Similarly, fire return intervals in savanna areas of South America, associated with biomass recovery after fires, are between one and four years (Bilbao et al., 2010;Pereira et al., 2014), and natural fires occur in a longer time interval (Durigan & Ratter, 2016;Pivello, 2011). Therefore, by accounting for a period of three years, we ensure that we are looking in the time-window most relevant to track the presence of ignition source and are able to generate a trend line with a statistical assessment. ...
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Timely spatially explicit warning of areas with high fire occurrence probability is an important component of strategic plans to prevent and monitor fires within South American (SA) Protected Areas (PAs). In this study, we present a five-level alert system, which combines both climatological and anthropogenic factors, the two main drivers of fires in SA. The alert levels are: High Alert, Alert, Attention, Observation and Low Probability. The trend in the number of active fires over the past three years and the accumulated number of active fires over the same period were used as indicators of intensification of human use of fire in that region, possibly associated with ongoing land use/land cover change (LULCC). An ensemble of temperature and precipitation gridded output from the GloSea5 Seasonal Forecast System was used to indicate an enhanced probability of hot and dry weather conditions that combined with LULCC favour fire occurrences. Alerts from this system were first issued in August 2020, for the period ranging from August to October (ASO) 2020. Overall, 50% of all fires observed during the ASO 2017–2019 period and 40% of the ASO 2020 fires occurred in only 29 PAs were all categorized in the top two alert levels. In categories mapped as High Alert level, 34% of the PAs experienced an increase in fires compared with the 2017–2019 reference period, and 81% of the High Alert false alarm registered fire occurrence above the median. Initial feedback from stakeholders indicates that these alerts were used to inform resource management in some PAs. We expect that these forecasts can provide continuous information aiming at changing societal perceptions of fire use and consequently subsidize strategic planning and mitigatory actions, focusing on timely responses to a disaster risk management strategy. Further research must focus on the model improvement and knowledge translation to stakeholders.
... Moreover, in the last decade, the growing pressure of the global demand for commodities has contributed to the increase of deforestation with the adoption of major land-use fire in the country, especially the burning of felled forest and improving the forage quality for cattle pastures. While federal rules prohibit natural resource exploitation in high biodiversity hotspots (such as national parks, biological reserves, and ecological research stations), the exceptions regarding the controlled burning of natural ecosystems in PNAs and indigenous reserves in the "National Fire Policy" (Durigan & Ratter, 2016;Nepstad et al., 2006) With an eye on PNAs, the inter-institutional planning instrument may minimize the negative effects of fire, recognizing the importance of its regulated and controlled use, by implementing alternative practices that contribute to protecting the environment and improving the communities' living conditions. ...
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Motivation: The combination of institutional weaknesses, climate change, and overexploitation is increasingly recognized as endangering the Amazon forest. These three factors made 2020 the worst year for forest fires recorded in the previous 60 years. We analyse environmental policies across the nine countries of the Amazon Basin to develop national and regional forest programmes to tackle this scenario. Purpose: The study synthesizes and compares key environmental legislation concerning protected natural areas (PNAs) and fire management in the nine countries of the Amazon Basin. To this end, the research question asks what directions can be drawn from a visualization and compilation of national regulations for future policy research and practice. Methods and approach: We undertake a critical literature review of PNAs and fire-management policies across the nine countries of the Amazon Basin and their further alignment using analyses of previous policy reviews on forest codes and land distribution. Findings: The article shows the heterogeneity of national fire-use and fire-management policies among the nine countries of the Amazon Basin. In addition, it suggests that top-down policies and regulations are likely to be characterized by misunderstandings (either direct or indirect) of local practice, rationale, and capacity; and, in some cases, risk criminalizing local and indigenous daily subsistence. Policy implications: The study indicates the need for more in-depth research and policy on participatory governance platforms for the use and management of fire, rather than fire-suppression and fire-risk adaptation strategies. There are some positive, albeit often isolated, cases, to which scholars, policy-makers, and environmental practitioners should pay more attention. © 2022 The Authors. Development Policy Review published by John Wiley & Sons Ltd on behalf of ODI.
... Fire elimination over a long period may cause the accumulation of fine fuel, which increases the intensity and severity of future fires (Harris et al., 2016). Studies show that both frequent and rare fire occurrences may affect conservation and biodiversity in the Brazilian cerrado (Durigan and Ratter, 2016). Hence, protected areas in Brazil have followed an international trend of integrated fire management (IFM), which aims to reduce fire occurrence at the end of the dry season and consequently to decrease the occurrence of large magnitude events (MMA et al, 2017). ...
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The area covered by the Brazilian cerrado biome has been greatly reduced in recent years due to the expansion of agricultural land and the increased number of fire outbreaks. The objective of this paper is to propose a methodology based on geospatial analysis and logistic regression analysis (LRA) for mapping the probability of fire occurrence in Brazilian cerrado conservation units. This model was applied in the Serra da Canastra National Park (SCNP) in the Southeast of Brazil. The methodology uses the maps of the following environmental variables, which are related to the danger of fire propagation: wind effect (WIN), terrain convexity (CVX), slope (SLO), drainage density (DRD), altitude (ELV), vegetation index (NDVI), and road density (ROD). The results of the LRA showed that the variables SLO, ELV, NDVI, ROD (p<0.0001), DRD (p=0.0005) and WIN (p=0.0007) contributed significantly to the occurrence of fire outbreaks. The model correctly classified 94.26% of cases. We conclude that this methodology can be used to inform the planning of firefighting actions in the Brazilian cerrado biome.
... These unique ecosystems play a critical role in storing carbon and maintaining the watersheds. Fires are an important part of maintaining this diversity, where too much or too little fire causes adverse effects on the ecosystem (Durigan and Ratter 2016). Unlike the humid Amazonia biome, where fires are almost exclusively anthropogenic (although rare, it is possible for naturally occurring wildfires to happen through ignition by lightning.), in the Cerrado fires can occur naturally (e.g. ...
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2015 saw the strongest El Niño event in the historical record, resulting in extreme drought conditions in Brazil. As drought conditions may also lead to greater fire danger, this study uses the 2015 fire in Brazil as a case study to examine whether and to what extent human-induced climate change has contributed to the fire weather conditions in the Cerrado and the southern Amazonia transitional forests known as the Arc of deforestation. Our results show that anthropogenic climate change is indeed a driver of meteorological conditions conducive to strong fire weather in these two regions, measured by fire weather index (FWI), especially on shorter timescales of daily and weekly. The anthropogenic climate change signal of FWI on short timescales corresponds to a similar order of increase in the FWI sub-indices (initial spread index and fine fuel moisture code) that can rapidly change due to the influence of the instantaneous weather conditions. For both regions the changes in fire weather in response to anthropogenic climate change are dominated by the combination of temperature and relative humidity responses. High FWI is more likely to occur under El Niño conditions, less likely under La Niña conditions, although the impacts of El Niño vs La Niña conditions are not symmetric when compared with El Niño Southern Oscillation neutral states. To summarize, both human-induced climate change and the presence of El Niño increased the likelihood of occurrence for the strong fire weather condition in 2015. Our results suggest that local and regional adaptation measures, such as improved drought monitoring and warning systems, could help with effective planning of fire prevention, firefighting actions, and disaster preparedness.
... The law for Protection of Native Vegetation (Article 38 of Law 12,561) prohibits the use of fire applied to vegetation, except for fires conducted for research purposes and in the context of agriculture and silviculture management. Although the fire exclusion policy aims to protect the fire sensitive ecosystems, such as forest formations, this policy has been shown to be unsuitable for fire-dependent ecosystems, such as savanna and grassland formations [4,13,86,113]. Over the past decades, several modifications have been reported in the fire regimes of the Cerrado, including higher fuel-loads and wildfires due to midterm fire absence and woody encroachment in areas with long-term fire absence [114]. ...
Article
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Fire is a significant agent of landscape transformation on Earth, and a dynamic and ephemeral process that is challenging to map. Difficulties include the seasonality of native vegetation in areas affected by fire, the high levels of spectral heterogeneity due to the spatial and temporal variability of the burned areas, distinct persistence of the fire signal, increase in cloud and smoke cover surrounding burned areas, and difficulty in detecting understory fire signals. To produce a large-scale time-series of burned area, a robust number of observations and a more efficient sampling strategy is needed. In order to overcome these challenges, we used a novel strategy based on a machine-learning algorithm to map monthly burned areas from 1985 to 2020 using Landsat-based annual quality mosaics retrieved from minimum NBR values. The annual mosaics integrated year-round observations of burned and unburned spectral data (i.e., RED, NIR, SWIR-1, and SWIR-2), and used them to train a Deep Neural Network model, which resulted in annual maps of areas burned by land use type for all six Brazilian biomes. The annual dataset was used to retrieve the frequency of the burned area, while the date on which the minimum NBR was captured in a year, was used to reconstruct 36 years of monthly burned area. Results of this effort indicated that 19.6% (1.6 million km2) of the Brazilian territory was burned from 1985 to 2020, with 61% of this area burned at least once. Most of the burning (83%) occurred between July and October. The Amazon and Cerrado, together, accounted for 85% of the area burned at least once in Brazil. Native vegetation was the land cover most affected by fire, representing 65% of the burned area, while the remaining 35% burned in areas dominated by anthropogenic land uses, mainly pasture. This novel dataset is crucial for understanding the spatial and long-term temporal dynamics of fire regimes that are fundamental for designing appropriate public policies for reducing and controlling fires in Brazil.
... The environmental consequences of these transformations are still poorly evaluated. The Cerrado biome covered almost 2 million km 2 60 years ago (Durigan and Ratter, 2015). Half of this area has been converted to pasture, in addition to annual crops, forestry, sugarcane, and intensive land use; the challenge is to reconcile conservation with agricultural production (Magalhães et al. 2020). ...
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The total column ozone (O 3 ) and nitrogen dioxide (NO 2 ) levels based on the satellite remote sensing for a period from 2005 to 2020 along with air temperature, rainfall and burned area in three biomes (Cerrado, Pantanal, and Atlantic Forest) from Mato Grosso do Sul - Brazil was evaluated. The annual variations of O 3 ranged from 260 DU for the Pantanal to 347 DU for the Cerrado. Whereas the NO 2 concentrations ranged from 2.95×10 ¹⁵ molecules for the Cerrado to 3.01×10 ¹⁵ molecules for the Atlantic Forest. The differences between NO 2 and O 3 concentrations on monthly and seasonal time scales, with higher values during the dry period (between July and October). The NO 2 and O 3 concentrations positively correlated with the burn areas in Pantanal and Cerrado, while the rainfall negatively correlated with these gases’ concentrations in these biomes The first principal component in all biomes is a comparison between rainfall and NO 2 , O 3 , a burned area, and air temperature with higher values of eigenvalues for the burned area in Pantanal, followed by Cerrado and Atlantic Forest, indicating more fires in Pantanal. Rainfall showed the highest value in the first principal components (PC). The second component in the Atlantic Forest was a balance between rainfall and air temperature with NO 2 , O 3 and burned area. In the Cerrado and Pantanal, a comparison is made between burned area and NO 2 , with rainfall, air temperature and O 3 . There are differences in the behavior of NO 2 and O 3 concentrations in biomes, driven by different environmental and anthropic variables.
... Disturbances are inherently linked to the functioning of tropical ecosystems and are necessary to sustain their species composition, biodiversity and structure (Durigan and Ratter, 2016;Kelly and Brotons, 2017;Schmidt et al., 2018). Yet, due to anthropogenic and climatic pressures, there is an increase in the frequency and severity of disturbances, such as large-scale wildfires, in tropical areas (Alencar et al., 2015;Fidelis et al., 2018). ...
Article
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An increase in the frequency and severity of disturbances (such as forest fires) is putting pressure on the resilience of the Amazon tropical forest; potentially leading to reduced ability to recover and to maintain a functioning forest ecosystem. Dense and long-term satellite time series approaches provide a largely untapped data source for characterizing disturbance- recovery forest dynamics across large areas and varying types of forests and conditions. Although large-scale forest recovery capacity metrics have been derived from optical satellite image time series and validated over various ecosystems, their sensitivity to disturbance (e.g. disturbance magnitude, disturbance timing, and recovery time) and environmental data characteristics (e.g. noise magnitude, seasonality, and missing values) are largely unknown. This study proposes an open source simulation framework based on the characteristics of sampled original satellite image time series to (i) compare the reliability of recovery metrics, (ii) evaluate their sensitivity with respect to environmental and disturbance characteristics, and (iii) evaluate the effect of pre-processing techniques on the reliability of the recovery metrics for abrupt disturbances, such as fires, in the Amazon basin forests. The effect of three pre-processing techniques were evaluated: changing the temporal resolution, noise removal techniques (such as time series smoothing and segmenting), and using a varying time span after the disturbance to calculate recovery metrics. Here, reliability is quantified by comparing derived and theoretical values of the recovery metrics (RMSE and R²). From the three recovery metrics evaluated, the Year on Year Average (YrYr) and the Ratio of Eighty Percent (R80p) are more reliable than the Relative Recovery Index (RRI). Time series segmentation tends to improve the reliability of recovery metrics. Recovery metrics derived from temporal dense Landsat time series tend to show a higher reliability than those derived from time series aggregated to quarterly or annual values. Although the framework is demonstrated on Landsat time series of the Amazon tropical forest, it can be used to perform such test on other datasets and ecosystems.
... The fire exclusion policies adopted by the CDNP since 2001, added to the anthropogenic activities in the park have contributed to the homogenization of fuel load distribution across the park and thus increased the risks of large-scale fires (Fidelis et al., 2018). Several studies have shown that maximum fire suppression can be a driver of intensifying fire regimes and is certainly an ineffective practice for tropical grassland and savanna ecosystems Conciani et al., 2021;Durigan and Ratter 2016;Durigan 2020;Schmidt and Eloy 2020). This policy is on the wrong way for the good functioning of flammable ecosystems, in which periodic fires are important for the creation and maintenance of the structure, composition, function, evolution and ecological integrity of their landscapes (Pivello, 2021;Simon et al., 2009). ...
Article
The flammable ecosystems are evolutionary dependent on the periodic action of fire. Several environmental factors, both at local and landscape scales, can affect fire regimes in these ecosystems differently. Here, we evaluated the influence of local and landscape features on two parameters of the fire regime of a flammable protected area of the Brazilian savanna: The Chapada Diamantina National Park. We characterized both fire frequency and the time since the last fire, from 1990 to 2019 and measured five environmental predictors (tree canopy cover, altitude, water surface, predominant land use and distance to the nearest municipality). We used Generalized Additive Models for Location, Scale and Shape (GAMLSS) to assess the influence of environmental predictors on the measured fire regime parameters. We found a large interannual variation in the total annual area burned in the studied period. In total, 68% of the protected area (1,030 km²) was burned at least once and 32% (486 km²) was unaffected by fires during the study period. Predominant land use, distance to the nearest municipality, tree cover and the interaction between tree cover and altitude were negatively related to fire frequency, while the water surface and altitude positively influenced fire frequency in the park. Compared to older fires, recent fires occurred in landscapes at lower altitudes and with lower tree cover. Our results demonstrate that the fire frequency and time since the last fire were highly variable across the park, reflecting the strong influence of landscape heterogeneity on their parameters.
... 6,[9][10][11] Unfortunately, human activities have been strongly impacting natural fire regimes in South American savannas and have become one of the most significant threats to these ecosystems. 12,13 Fire regime changes have been closely linked to both large-scale conversion of natural vegetation and conservation policies focused on fire suppression, which can lead to profound changes in landscape configuration and favors the occurrence of wildfires during critical periods of drought. 14 Impacts include exclusion of fire-sensitive species, 15,16 alteration of physical and chemical soil composition, 17 and higher levels of greenhouse gas emission. ...
... Finally, because consistent fire policies are urged for Cerrado conservation [55], and objective regulations require a better comprehension of the fire scenario, FM can be an important tool for providing detailed information about the fire behavior in the region. ...
Article
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MATOPIBA is an agricultural frontier, where fires are essential for its biodiversity maintenance. However, the increase in its recurrence and intensity, as well as accidental fires can lead to socioeconomic and environmental losses. Due to this dual relationship with fire, near real-time (NRT) fire management is required throughout the region. In this context, we developed, to the best of our knowledge, the first Machine Learning (ML) algorithm based on the GOES-16 ABI sensor able to detect and monitor Active Fires (AF) in NRT in MATOPIBA. To do so, we analyzed the best combination of three ML algorithms and how long it takes to consider a historical time series able to support accurate AF predictions. We used the most accurate combination for the final model (FM) development. The results show that the FM ensures an overall accuracy rate of approximately 80%. The FM potential is remarkable not only for single detections but also for a consecutive sequence of positive predictions. Roughly, the FM achieves an accuracy rate peak after around 20 h of consecutive AF detections, but there is an important trade-off between the accuracy and the time required to assemble more fire indications, which can be decisive for firefighters in real life.
... Historically, natural fires impacting small areas occurred in the early rainy season. However, the fire regime is changing at the biome scale, with an increase in the burned area and fire frequency, mainly because of the human use of fire in converting native vegetation to farmland (Durigan & Ratter 2016;Schmidt & Eloy 2020). The effect of fire regime changes on riparian forests is worrisome, especially considering ongoing climate change. ...
Article
Fire can change gallery forest vegetation structure, thereby altering nutrient fluxes between terrestrial and aquatic ecosystems. In Brazilian savannas, which are fire‐prone ecosystems, the fire regime is changing due to human activities such as converting native vegetation to farmland and urban areas. Uncontrolled wildfires in these savannas can reach gallery forests, which are more sensitive to fire impacts, leading to concerns about the effects of fire on gallery forest vegetation structure and freshwater ecosystems. We analysed the relationships between fire severity (the degree to which the fire has changed an area), percentage of burned area, variation in precipitation with gallery forest and savanna vegetation structure recovery and input of nutrients (NH4, NO2−, NO3− and PO43-) to streams for 16 months after a fire event in five watersheds associated with small streams. One year after the fire, vegetation recovery (NDVI) was lower in gallery forest areas than in savanna woodlands, despite the more severe fires in savannas. The short‐term effects of fire on gallery forest vegetation included increased nitrate concentrations in streams, which were also influenced by increased precipitation and the extent of the burned area. The nutrient inputs into the stream stabilized within 1 year. However, gallery forest vegetation did not fully recover at that time and may continue to alter the functioning of the aquatic ecosystem. Together, these results demonstrate the need for an integrated fire management plan that considers both gallery forests and the surrounding savannas in the landscape to address consequences to aquatic ecosystems. O fogo pode alterar a estrutura da vegetação de florestas ripárias, alterando assim os fluxos de nutrientes entre os ecossistemas terrestres e aquáticos. Nas savanas brasileiras, que são ecossistemas propensos ao fogo, o regime de fogo está mudando devido a atividades humanas tais como a conversão de vegetação nativa em áreas agrícolas e urbanas. Eventos de fogo descontrolado em savanas podem atingir as florestas ripárias, que são mais sensíveis aos impactos do fogo, levando a preocupações sobre os efeitos do fogo na estrutura da vegetação de tais florestas e nos ecossistemas aquáticos associados. Nós analisamos as relações entre a severidade do fogo (o grau em que o fogo alterou uma área), percentagem de área queimada, e a variação da precipitação com a recuperação da estrutura de florestas ripárias e da vegetação em áreas de savana, e a entrada de nutrientes (NH4, NO2, NO3−, e PO43−) nos cursos de água ao longo de 16 meses após um evento de passagem do fogo em cinco bacias hidrográficas associadas a pequenos cursos de água. Um ano após a passagem do fogo, a recuperação da vegetação (NDVI) foi menor nas áreas de florestas ripárias do que nas savanas, apesar do fogo mais intenso nas savanas. Os efeitos em curto prazo do fogo em florestas ripárias incluíram o aumento das concentrações de nitrato nos cursos de água, o que também foi influenciado pelo aumento da precipitação e pela extensão da área queimada. As entradas de nutrientes nos córregos estabilizaram no prazo de um ano. Contudo, a vegetação de florestas ripárias não havia se recuperado totalmente após esse período e podendo continuar a alterar o funcionamento dos ecossistemas aquáticos. Juntos, estes resultados demonstram a necessidade de um plano integrado de gestão de incêndios que considere tanto as formações florestais ripárias como as savanas circundantes na paisagem, a fim de abordar as consequências para os ecossistemas aquáticos.
... Thus, fire events in this system are frequent, although generally of low intensity, consuming most of the aboveground biomass (Miranda et al. 2009;Rissi et al. 2017;Rodrigues et al. 2021;Silva et al. 2021), and ensuring the renewal of the herbaceous layer that re-sprouts after these events (Pilon et al. 2021;Zupo et al. 2021). In contrast, the suppression of fire, which consequently will promote an increase of dead aboveground biomass, can lead to a heightened probability of uncontrollable wildfires that can have significant detrimental effects on plant community regeneration (Durigan and Ratter 2016;Fidelis et al. 2018). Long periods of fire exclusion can also result in a shift of plant community structure and composition, both by woody encroachment and an associated reduction in biodiversity, resulting in changes in ecological processes (Abreu et al. 2017). ...
Article
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Belowground bud bank regeneration is a successful strategy for plants in fire-prone communities. It depends on the number and location of dormant and viable buds stored on belowground organs. A highly diverse belowground bud-bearing organ system maintained by a frequent interval of fire events guarantees the supply of a bud bank that enables plants to persist and resprout after disturbance. We investigated how different fire exclusion and fire frequencies, affected the herbaceous layer in tropical savannas, by assessing belowground persistence and regeneration traits. Contrary to our hypothesis, we found that under a shorter fire exclusion period, the total bud bank increased at a lower fire frequency. But sites at longer fire exclusion and infrequent fire, the bud bank was smaller the longer the period since the last fire. However, the major shift was concerning organ diversity since fire exclusion was more related to loss of belowground diversity rather than decreasing of the belowground bud bank size. Furthermore, fire-associated bud-bearing structures like xylopodia disappeared in the fire suppressed areas, whereas clonal organs, such as rhizomes, developed in the bud bank. By quantifying belowground bud bank traits under different fire histories, we highlight the importance of the local fire regime on the composition of the belowground plant components, which can affect the tropical savanna aboveground plant community. Given that, loss of the belowground bud-bearing component of the plant community will have a direct effect on vegetation regeneration in post-fire environments, and consequently, on plant community resilience.
... savannas, which are open habitats, with a tree component that does not form a closed canopy. Differently from seasonally dry forests, the savannas are covered by a significant grass component and its species are exposed to regular fires, which are key for the maintenance of its biodiversity(Abreu et al., 2017;Dexter et al., 2018;Durigan & Ratter, 2016;Parr et al., 2014;Simon & Pennington, 2012). Within Anemopaegma, species are generally restricted to a single habitat, although some species may be found in up to two different habitats as defined here. ...
Article
The biotic assembly of one of the most species‐rich savannas, the Brazilian Cerrado, has involved recruitment of lineages from several surrounding regions. However, we lack a clear understanding about the timing and pathways of biotic exchanges among these regions and about the role those interchanges had in the assembly of Neotropical biodiversity. We investigated the timing and routes of species movements between wet or seasonally dry habitats across Neotropical regions and assessed the potential for ecological adaptation by evaluating the habitat transitions correlated with morphological shifts. Neotropics. The plant genus Anemopaegma (Bignonieae, Bignoniaceae). We inferred a Bayesian molecular phylogeny of Anemopaegma using one nuclear and two chloroplast markers. We sampled more than 90% of the known species diversity of Anemopaegma, covering its full geographical range. We estimated divergence times using a Bayesian relaxed‐clock approach and inferred ancestral ranges as well as shifts in habitat and morphological characters. Phylogenetic analyses recovered seven main clades within Anemopaegma. The genus likely originated in Amazonia in the late Oligocene. Early‐diverging lineages diversified in situ in Amazonia, particularly during the Miocene, with independent dispersal events to the Andes, Atlantic Forest and Cerrado. Shifts from seasonally dry forest to savanna habitats were correlated with shifts from liana to shrub and the loss of tendrils. The timing of diversification of major lineages within Anemopaegma is consistent with major geological and climatic events that occurred during the late Palaeogene and Neogene, such as the Andean uplift and the Middle Miocene Climatic Optimum. Movements across different regions within the Neotropics were relatively common but shifts between habitats were not. The correlation in the evolution of the shrubby habit, the loss of tendrils and the shifts from forest to savanna are consistent with a scenario of ecological adaptation.
... Further, they lose visibility for being subsumed under more general terms like 'pasture' that also are used for human-created systems. The consequences of these misperceptions are clearly reflected in Brazilian conservation policies that have focused on fire suppression and management exclusion, threatening grassy ecosystems and their high biodiversity (Durigan and Ratter, 2016). Additionally, grassy ecosystems are highly vulnerable to global change (e.g., Hofmann et al., 2021). ...
Article
In Brazil, the country with the highest plant species richness in the world, biodiverse savannas and grasslands – i.e., grassy ecosystems, which occupy 27% of the country – have historically been neglected in conservation and scientific treatments. Reasons for this neglect include misconceptions about the characteristics and dynamics of these ecosystems, as well as inconsistent or regionally restricted terminology that impeded a more adequate communication about Brazil's savannas and grasslands, both within the country and internationally. Toward improved communication and recognition of Brazil’s diversity of ecosystems, we present the key drivers that control the main types of grassy ecosystems across Brazil (including in regions of the country where forests dominate). In doing so, we synthesize the main features of each grassy ecosystem in terms of physiognomy and ecological dynamics (e.g., relationships with herbivores and fire). We propose a terminology both for major grassland regions and for regionally relevant vegetation physiognomies. We also discuss terms associated with human land management and restoration of grassy ecosystems. Finally, we suggest key research needs to advance our understanding of the ecology and conservation values of Brazil’s grassy ecosystems. We expect that a common and shared terminology and understanding, as proposed here, will stimulate more integrative research that will be fundamental to developing improved conservation and restoration strategies.
... Although little is known about the contribution of PyC to the chemical properties of soil organic matter (SOM) stored in Cerrado soils, some tropical savannas have been increasingly submitted to fire suppression policies (Abreu et al., 2017;Durigan and Ratter, 2016). This suggests that proportionally more fresh plant material would be added to the soils in these ecosystems at the expense of PyC inputs. ...
Article
In fire-prone ecosystems such as the Brazilian Cerrado, pyrogenic C (PyC) can be a relevant contributor to soil C pools. However, the extent to which increasing additions of fresh plant litter can affect the relative contribution of PyC to soil organic matter (SOM) remains unclear. To address this question, we used a 12-month laboratory incubation experiment arranged according to a complete factorial scheme including: three Ferralsols, two depths i.e. topsoil (0–10 cm) and subsoil horizons (60–100 cm), and two levels of a doubly isotope-labeled (¹³C and ¹⁵N) plant litter (0 and 40 mg g⁻¹ soil), with three blocks as replicates. After the incubation, the samples were physically fractionated to isolate SOM within the particle-size fractions (PSF) greater and smaller than 53 µm. Subsequently, we quantified the amount of litter-derived C and N remaining in both PSF and used hydrofluoric (HF) acid 10% (v/v) to demineralize the PSF smaller than 53 µm, yielding the HF-insoluble SOM. This fraction was evaluated with ¹³C/¹⁵N–nuclear magnetic resonance (NMR) spectroscopy by applying the multiple cross-polarization (multiCP) pulse sequence with magic-angle spinning (MAS), yielding semiquantitative solid-state NMR spectra. Averaged across the Ferralsols, the PSF smaller than 53 µm retained about 22.8% of the C and 32.6% of the N added via plant litter. Our NMR results indicated that the incorporation of litter-C and -N led to an increase in aliphatic C (0–110 ppm) coupled to a marked decrease in aromatic moieties (115–154 ppm), particularly nonprotonated aromatics in subsoil samples. Consequently, there was a significant decrease in the aromaticity of SOM. Therefore, with increasing additions of fresh plant material, soil C dynamics in Cerrado Ferralsols may become less reliant on the relative contribution of nonprotonated aromatics to SOM chemistry.
... Unlike forest ecosystems, in which fire is mainly harmful, fire can benefit the dynamics of savannas (Bond & Keeley, 2005;Pivello et al. 2021), but this issue is still poorly understood by society and environmental agencies in Brazil. Research studies on Cerrado fire dynamics over the last five decades (Coutinho 1982, 1990, Pivello & Norton 1996, Pivello & Coutinho 1996, Miranda 2010, Fidelis et al. 2018) as well as practical knowledge coming from protected area managers , Berlinck & Batista 2020, Berlinck & Lima 2021) have contributed to slowly change the zero-fire policy rooted in the country for centuries (Durigan & Ratter 2016, Pivello et al. 2021) towards prescribed and controlled fires, and integrated fire management. Recent environmental legislation has incorporated these new approaches by accepting controlled fires in specific situations Pivello et al. 2021). ...
Article
The fire regime is essential in creating a mosaic of plant structure and diversity in South American open savannas, especially favouring herbs. However, studies investigating diversity patterns in Neotropical savannas rarely focus on the herb–subshrub layer. This study investigated the variation of the herb–subshrub layer under contrasting fire regimes in the most conserved site within the Cerrado Domain, the Jalapão region, Brazil. We selected four sites of open savanna physiognomy with similar topographic, climatic and edaphic features: three burned every 2 years, while the fourth site has remained unburned for at least the last 10 years. We randomly distributed 15 plots of 4 m ² in each site and identified all herbs and subshrubs in each plot to estimate density, richness, alpha diversity and species composition. The unburned site had lower herb–subshrub density, richness and diversity than the frequently burned sites. Species composition varied between frequently burned and unburned sites, partially explained by the fire frequency across sites. Although other ecological factors may explain the patterns detected, we cannot rule out the importance of fire in structuring plant communities in the Jalapão region. As in other savannas, our study in the Cerrado Domain reinforces the essential role of the fire regimes in modifying and maintaining the diversity of herbaceous plants at the landscape scale.
Article
Increases of air temperature due to global warming suggest that plants could be exposed to temperatures above their optimum range for performing specific physiological functions in the future. Declines in carbon exchange rates would lead to significant decreases in species performance, particularly in those lacking traits associated to heat tolerance. Savannas and semi-deciduous forests are ecosystems with high biological diversity, scattered throughout the Neotropical landscape, and very dynamic areas controlled by species traits. Significant increases in air temperatures can affect such areas if plant species of these forests lack heat tolerance. We performed heat tolerance assays to obtain T50 values of the photosystem II (PSII) of 30 Neotropical tree species from a savanna (15 species) and a semi-deciduous forest (15 species). Our goal was to test whether the typical savanna species are more heat-tolerant than semi-deciduous forest species. We also assessed if T50 was correlated with leaf morphological traits such as specific leaf area and leaf thickness. We found savanna tree leaves with lower specific leaf area, higher thickness, and higher T50 values than semi-deciduous forest plants (49.36 °C vs. 47.65 °C, respectively). Specific leaf area was negatively correlated to T50 values. Our findings suggest that semi-deciduous forest species would be more affected by temperature increases than savanna species. Whereas species traits play an important role in the dynamics of forest–savanna areas, savanna species would be favored under warmer temperatures.
Article
Woody plant encroachment is a reality in many savannas worldwide, leading savannas to become replaced by forest ecosystems. As tree density and cover increase, increased shade and litter deposition may suppress the savanna’s community of low‐lying plants. By using field manipulation, we tested shading and litter effects, alone and in combination, on the savanna’s ground‐layer plant community. We investigated how changes in these environmental factors may affect the composition, structure, and aboveground biomass in the plant community of a species‐rich Neotropical savanna. Savanna patches in the Cerrado, southeastern Brazil. Annual surveys of the herbaceous‐shrub layer in a three‐year field manipulation experiment examining shading and litter deposition. Shade negatively affected all evaluated parameters, while litter addition had only minor effects. The largest losses of richness, density, and cover occurred in forbs and grasses. Increased shade resulted in a sharp decrease in the aboveground biomass of monocots. Our results show that light is a strong environmental filter for the ground‐layer community. The reductions in grass cover and biomass under shade treatments likely altered ecosystem functioning. Woody encroachment can thus be considered to represent a process that can alter the structure and functioning of savannas. Management interventions should therefore be taken to prevent woody encroachment or mitigate its harmful effects on savanna biodiversity and ecosystem functioning.
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The Cerrado region has adapted to fires because of its climate and vegetation conditions, but with increasing frequency, regional fires will begin to degrade the biome. Therefore, research is necessary to determine whether the occurrence of fires is beneficial or degrading to the environment, and if the fire origin is natural or anthropic. The objective of this study was to evaluate the vulnerability of vegetation to different scenarios of future climate change. The study area was the Ecological Station of Uruçuí-Una, located in the south of Piaui. The methodology consisted in identifying burnt areas in terms of their recurrence; evaluating the correlation between burnt areas and precipitation and temperature; analyzing burnt areas and the Mann Kendall trend for vegetation for the period 2001 to 2018. Based on the current vegetation conditions, the vegetation and land use were estimated for the year 2100 through the Markov chain and the vulnerable areas were estimated observing different scenarios of climate change of the Coupled Model Intercomparison Project Fase 6 (CMIP6). The results indicated that fires with frequencies above 5 in the interval of 18 years have a negative Pearson correlation and the Mann-Kendall analysis, which implies a state of vegetation degradation. Regarding the future climate scenarios, savanna sites with temperatures above 38 °C, a vegetation index below 0.4, and monthly precipitation less than 90 mm were those with the highest level of vulnerability. Vulnerability mapping can help to improve public policies for fire management for the sustainable development of this region.
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The objective of this work is to evaluate the effect of fire on ant assemblages in savanna and forest typologies in the Reserva Natural da Serra do Tombador in Cavalcante – Goiás, Brazil. Ant pitfalls traps were installed and subdivided into Burnt Cerrado (BC), Unburnt Cerrado (UC), Burnt Forest (BF) and Unburnt Forest (UF), and the samples were sorted, assembled and identified. The constancy and abundance of individuals, and the frequency of distribution of the genera in the total area and by treatment were evaluated. The UF, BF, UC and BC had 19, 14, 8 and 15 genera, with Jackknife 1 index indicating 18.5, 24.4, 8.9 and 20.4 respectively. The Shannon diversity index for the genera was 0.8462, 0.7604, 0.6448 and 0.5992 for UF, BF, BC and UC respectively. The Cerrado showed greater abundance of individuals and greater ant diversity index in relation to Forest when in presence of fire.
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South American savannas are an ancient, open, and species-rich ecosystem, currently threatened by numerous anthropogenic impacts, including human-driven climate change. In this chapter, we synthesize available evidence on how climate change likely will affect regeneration from seeds, focusing on the Brazilian Cerrado, a Neotropical mosaic of vegetation types. We conducted a literature survey to evaluate the main environmental drivers (fire, temperature, drought) affecting regeneration of plants from seeds in a changing climate. Unlike Mediterranean ecosystems, germination of most Cerrado species is not stimulated by fire-related cues, but heat-tolerant propagules would be selected under increasing fire frequency scenarios. Emergence from soil seed banks is closely related to the distinct rainy season, but seed drought tolerance and seed bank recruitment are not well studied. We propose a list of key research areas that need to be addressed to increase our predictive power on the effects of climate change on regeneration of plants from seeds in tropical savannas.
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Tropical forests are recognized for their role in providing diverse ecosystem services (ESs), with carbon uptake the best recognized. The capacity of tropical forests to provide ESs is strongly linked to their enormous biodiversity. However, causal relationships between biodiversity and ESs are poorly understood. This may be because biodiversity is often translated into species richness. Here, we argue that focusing on multiple attributes of biodiversity—structure, composition, and function—will make relationships between biodiversity and ESs clearer. In this review, we discuss the ecological processes behind ESs from tropical humid and subhumid forests of South America. Our main goal is to understand the links between the ESs and those three biodiversity attributes. While supporting and regulating services relate more closely to forest structure and function, provisioning services relate more closely to forest composition and function, and cultural services are more related to structure and composition attributes. In this sense, ESs from subhumid forests (savannas) differ from those provided by the Amazon Forest, although both ecosystems are recognized as harboring tremendous biodiversity. Given this, if anthropogenic drivers of change promote a shift in the Amazon Forest toward savanna—the savannization hypothesis—the types of services provided will change, especially climate regulating services. This review emphasizes the importance of deeply understanding ecosystem structure, composition, and function to better understand the services ecosystems provide. Understanding that anthropogenic impacts on biodiversity occur through these three main attributes, it becomes easier to anticipate how humans will impact ESs.
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Protected areas (PAs), which are a major tool for conserving land cover and ecosystem services, are expected to restore natural fire regimes and allow better fire management methods. However, little is known about the relationship between protected area (PA) establishment and fire risk. Using field plots in the National Forest Inventory (NFI) of China, this study is designed to assess the association of PA establishments and fire risk. We find that PA establishments have been significantly related with the decrease of the fire occurrence probability. We also find that forest ownership is a key factor influencing fire activities within protected areas. Inside protected areas, privately or collectively owned plots have a much higher fire occurrence probability than state-owned plots. Empirical evidences shows that inadequate compensation from protects areas of China is one possible reason for the higher fire risk in collective or individual owned forests. As a solution, more financial compensation within PAs is urgently needed in China.
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Humans have been changing the natural fire regimes in most Brazilian vegetation types for over 4000 years. Natural lightning fires can easily happen in savannas and grasslands, but they are rare in the moist rainforests. Today, anthropogenic fires are frequent in both the fire-adapted cerrado (Brazilian savanna) and the fire-sensitive rainforest. In this paper, I compare two very different biomes concerning their susceptibilities and responses to fire: the Amazon rainforest and the cerrado. I present an overview of their fire history, especially regarding human-made fires for land management, and pull together information about the use of fire by indigenous peoples in the cerrado and the Amazon, as this information is very fragmented. Accordingly, I describe how fire regimes have changed in these biomes over time due to agricultural practices and the consequences of the current altered fire regimes. After European settlement, fire frequency greatly increased in the cerrado, especially related to cattle ranching, and more recently in the more seasonal landscapes in the Amazon. In cerrado natural preserves, however, managers try to keep fire away, but wildfires eventually come and develop into destructive events. Actions to reduce biodiversity loss and environmental deterioration due to inappropriate fire management are necessary and should be very distinct in both areas: in the Amazon they would include the development of policies to stimulate fire-free, small-scale agricultural projects, and in the cerrado, sustainable use of fire for cattle ranching is possible but the regimes must be fitted to local specific features in order to avoid land degradation. In cerrado conservation areas, proper fire management programs based on scientific knowledge and the incorporation of the traditional expertise of indigenous peoples are needed to maintain the biological diversity, to maintain the ecological processes, and to reduce wildfires.
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The main objective of our study was to provide consistent information on land cover changes between the years 1990 and 2010 for the Cerrado and Caatinga Brazilian seasonal biomes. These areas have been overlooked in terms of land cover change assessment if compared with efforts in monitoring the Amazon rain forest. For each of the target years (1990, 2000 and 2010) land cover information was obtained through an object-based classification approach for 243 sample units (10 km × 10 km size), using (E)TM Landsat images systematically located at each full degree confluence of latitude and longitude. The images were automatically pre-processed, segmented and labelled according to the following legend: Tree Cover (TC), Tree Cover Mosaic (TCM), Other Wooded Land (OWL), Other Land Cover (OLC) and Water (W). Our results indicate the Cerrado and Caatinga biomes lost (gross loss) respectively 265,595 km2 and 89,656 km2 of natural vegetation (TC + OWL) between 1990 and 2010. In the same period, these areas also experienced gain of TC and OWL. By 2010, the percentage of natural vegetation cover remaining in the Cerrado was 47% and in the Caatinga 63%. The annual (net) rate of natural vegetation cover loss in the Cerrado slowed down from −0.79% yr−1 to −0.44% yr−1 from the 1990s to the 2000s, while in the Caatinga for the same periods the rate increased from −0.19% yr−1 to −0.44% yr−1. In summary, these Brazilian biomes experienced both loss and gains of Tree Cover and Other Wooded Land; however a continued net loss of natural vegetation was observed for both biomes between 1990 and 2010. The average annual rate of change in this period was higher in the Cerrado (−0.6% yr−1) than in the Caatinga (−0.3% yr−1).
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1 It was hypothesized that if facilitation is important for seedling establishment in savanna, then fire should reduce seedling establishment. 2 This was tested in the cerrado savanna of Brazil with a factorial experiment designed to evaluate the effects of cover and prescribed burning on seedling establishment. 3 Seeds of 12 species of trees and shrubs were sown in plots located in sites providing three densities of woody cover and four times since last burning. 4 Seedling establishment generally was greater under the crowns of trees than in open grassland, but individual species responded differently to cover. Eight of the 12 species responded favourably to cover, but a single species showed reduced establishment with increasing cover. 5 Burning had an overall negative effect on seedling establishment in the first year following burning. By the second year following burning, establishment returned to control levels. 6 An irrigation experiment with two species demonstrated that rain-free periods within the wet season had negative effects on seedling establishment. 7 A litter-removal experiment with Miconia albicans revealed that, at least for this species, litter has a negative effect upon seedling establishment in densely wooded sites and positive effects in open grassland.
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Recent studies indicate that after protection from human pressures (fire, cattle grazing and agriculture), structural changes occur in the cerrado vegetation, changing open physiognomies into more closed savannas. We analyzed the dynamics of vegetation types along 44 years, at Assis Ecological Station, one of the rare conservation units protecting the cerrado biome in the southeastern São Paulo State, Brazil, with the aim of characterizing and quantifying those changes in space and time. Protected against human pressures since a long time, field observations have shown an upgrade of local cerrado physiognomies, through a successional process whose structural climax can be a forest physiognomy, with a continuous arboreal stratum. The dynamics of the vegetation types was analyzed by using aerial photographs (1962, 1984 and 1994), Quick Bird satellite images (2006) and field surveys. During this 44 years period, field physiognomies were reduced from 23% to less than 1% of the total area studied. In the other extreme, woodland savanna increased from 53% to 91% of the area. Changes did not happen at the same rhythm across the area, and that is apparently correlated to microclimate and edaphyc differences. We believe that field and savannic physiognomies initially existing were mostly maintained due to heavy human pressures, constraining the secondary succession towards an edapho-climatic climax of greater biomass. Confirming the observations of cerrado areas elsewhere, protection against fire, cattle grazing and agriculture allowed the evolution of open vegetation types into more closed ones, tending to be locally extinct the first if new disturbances do not occur. Consequences of these changes related to management strategies, biodiversity conservation and carbon sink are discussed.
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The area evaluated in this study was a continuous stretch comprising three vegetation formations: gallery forest, semideciduous seasonal forest and cerradão (woodland savanna). The aim of this study was to examine the tree community dynamics in a forest gradient—from gallery forest to cerradão—at Panga Ecological Station, in the city of Uberlandia, located in the state of Minas Gerais, Brazil. The study was based on data from a previous inventory of the continuous forest conducted in 211 permanent 10 × 10 m sample plots in eight parallel transect running perpendicular to Panga Creek. Trees with a diameter at breast height ≥ 4.77 cm were sampled in 1997, 2002 and 2007. With the exception of the cerradão, there was a net reduction in tree density over the studied period of ten years, because mortality rates were higher than the recruitment rates. The basal area increased during the period of the study, especially at cerradão. The mean mortality rate in the studied area was 2.64%.yr−1 and 3.36%.yr−1 for the 1997-2002 and 2002-2007 periods, respectively, whereas the mean recruitment rate was 1.76%.yr−1 and 1.97%.yr−1, respectively. In general, mortality rates and recruitment rates have increased during the two successive periods of measurement and showed an imbalance in favor of mortality for the semideciduous seasonal forest and the gallery forest. This fact, added to the low density and high basal area, suggest that there was a process of thinning in the tree community. However, at cerradão, there was an imbalance in favor of recruitment, with a consequent increase in density and basal area, indicating that the cerradão is in a construction phase, which was further favored by a decrease in the occurrence of fire and other anthropogenic disturbances. When the turnover rates are taken into consideration, the global dynamics of the study area over the ten years evaluated can be expressed as cerradão > semideciduous seasonal forest > gallery forest.
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O objetivo do trabalho foi analisar as mudanças na comunidade lenhosa em um período de quatro anos. Foram estabelecidas 50 parcelas permanentes de 10 × 10 m onde foram amostrados todos os indivíduos com diâmetro a 30 cm acima do solo (DAS 30 cm) > 5 cm em 2002 e em 2006. No inventário de janeiro de 2002, foram encontrados 945 indivíduos pertencentes a 77 espécies, 65 gêneros e 35 famílias ao passo que em janeiro de 2006 foram 1.106 indivíduos distribuídos em 80 espécies, 66 gêneros e 36 famílias. A diversidade de espécies e a estrutura diamétrica da comunidade não diferiram no período. As taxas de mortalidade (4,01% ano-1) e de perda de área basal (0,68% ano-1) foram compensadas pelas taxas de recrutamento (6,67% ano-1) e de ganho de área basal (2,26% ano-1), indicando a manutenção da comunidade como aparentemente estável. O incremento periódico anual (IPA) da comunidade foi de 0,31 cm ano-1, sendo superado pelo IPA de Euplassa inaequalis, Kielmeyerarubriflora e Byrsonima coccolobifolia (0,72, 0,49 e 0,47 cm ano-1, respectivamente), indicando o potencial de crescimento de tais espécies como importante para estratégias de recuperação de áreas degradadas. A ausência de fogo no período estudado pode ter sido o fator responsável pela dinâmica da vegetação do cerrado estudado, favorecendo o estabelecimento de algumas espécies lenhosas e proporcionando aumento em densidade e biomassa.
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Palm swamps (veredas) are unique and diverse plant communities associated with the headwaters of streams in central Brazil, and they are frequently subjected to fires. We evaluated the effect of fire and the role of different fire-related cues on inducing reproduction by palm swamp vegetation. We compared the responses of species in burned plots, in plots in which the aboveground vegetation was clipped and then removed, and in unburned and unclipped control plots. Both the number of reproductive species and the total number of flowers/fruits produced by all species monthly were significantly greater in the burned than in the clipped and control plots, and greater in the clipped than in the control plots. For 34 of the 48 individual species analyzed the number of flowers/fruits produced per m2/month was greater in the burned than in the control plots, whereas the clipping treatment significantly increased the reproductive rate of only six species. This indicates that increased light availability was not the only factor inducing plant reproduction. Most likely, plant reproduction was also stimulated by the availability of soil nutrients whose concentrations increased significantly after burning. Although our results indicate that most plant species that occur in palm swamps are fire-recruiters, care must be taken in using fire as management tool, especially as the frequency of human-induced fires in palm swamps have increased dramatically in recent years.
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As in other savanna biomes, burns are common in the Cerrado biodiversity hotspot, profoundly affecting its entire biota. We review the direct and indirect effects of fire on lizards and find that previous studies on herpetofauna report little or no direct postfire mortality, likely as a result of adaptive behaviors, and that studies on indirect effects of burns often assume the absence of direct effects on the herpetofauna. We investigate the immediate effects of prescribed fires upon lizard mortality in three South American Cerrado physiognomies. We also investigate the short-term (12 months) effects of fire on lizard captures in cerrado sensu stricto, the most widespread Cerrado physiognomy. We found no immediate postfire mortality with lizards using burrows and termite nests as prime shelters. Most lizard species displayed narrowed microhabitat use and reduced activity immediately after the fire. Twelve months after the burn, the capture rate of most species increased or remained the same as before the fire, whereas Mabuya nigropunctata (Scincidae) displayed reduced capture rates. With no apparent mortality caused directly by fire, we attribute variation in capture rates to changes in habitat structure. These changes may represent increased food resources or amelioration of microclimatic and structural conditions to the benefit of the majority of lizard species but which can also be detrimental to some species. Our results indicate that lizards are adapted in many ways to fires in the Cerrado.
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The objective of this study was to produce an updated vegetation map of the Estação Ecológica do Panga (EEP) (Uberlândia, MG, Brazil), and use this map to document changes in the distribution of cerrado plant physiognomies along the 404 ha of the reserve. To do so we compared a map of the vegetation cover in 1987, soon after the reserve had been created, with one for 2005 created using the analysis of a georeferenced Quickbird multispectral satellite image. We found there was an increase in mata mesófila (from 7.0% of the reserve in 1987 to 11.4% in 2005), cerradão (from 2.5% to 4.3%), cerrado sentido restrito (from 37.5% to 43.7%) and campo cerrado (from 12.5% to 34.2%). In contrast, the campo sujo that occupied approximately 30% of the reserve in 1987 practically disappeared (only 0.4% in 2005). There was also a reduction in the amount of campos úmidos and veredas (from 9.0% to 5.8%) and anthropogenically altered areas (from 1.5% to 0.1%). Our
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Fire is an important ecological factor in Cerrado vegetation of Central Brazil. The effect of fire on the abundance of large mammalian herbivores was studied at Reserva Xavante do Rio das Mortes, a 32 9000 ha cerrado Reserve in Mato Grosso, Brazil. Track counts were used to compare the abundance of tapir, marsh deer and pampas deer along 7 burned and 7 unburned transects on 7 occasions between August 1995 and August 1996. The number of tracks in burned and unburned areas did not have significant differences. Mammal herbivores use burned areas probably because of renewed food resources. Fire management is recommended at Reserva Xavante do Rio das Mortes.
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Although biomass burning of savannas is recognised as a major global source of greenhouse gas emissions, quantification remains problematic with resulting regional emissions estimates often differing markedly. Here we undertake a critical assessment of Australia's National Greenhouse Gas Inventory (NGGI) savanna burning emissions methodology. We describe the methodology developed for, and results and associated uncertainties derived from, a landscape-scale emissions abatement project in fire-prone western Arnhem Land, northern Australia. The methodology incorporates (i) detailed fire history and vegetation structure and fuels type mapping derived from satellite imagery; (ii) field-based assessments of fuel load accumulation, burning efficiencies (patchiness, combustion efficiency, ash retention) and N : C composition; and (iii) application of standard, regionally derived emission factors. Importantly, this refined methodology differs from the NGGI by incorporation of fire seasonality and severity components, and substantial improvements in baseline data. We consider how the application of a fire management program aimed at shifting the seasonality of burning (from one currently dominated by extensive late dry season wildfires to one where strategic fire management is undertaken earlier in the year) can provide significant project-based emissions abatement. The approach has wider application to fire-prone savanna systems dominated by anthropogenic sources of ignition.
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1. Fire is an important disturbance in African savannas where it is generally assumed that high levels of pyrodiversity (variation in aspects of the fire regime) are necessary to maintain high levels of biodiversity. There is, however, little empirical evidence in support of this hypothesis for animals.Furthermore, the relationship between pyrodiversity and biodiversity may vary with différent savanna types, shaped by mean annual precipitation. 2. We made use of a long-term burning experiment to investigate the effect of interactions between precipitation and pyrodiversity on biodiversity. We sampled termites (major ecosystem engineers in savannas) within experimental plots involving a range of fire seasons and frequencies. Sampling was conducted in three distinct savanna types along a rainfall gradient in South Africa. We explored how termite diversity varied with mean annual precipitation and whether faunal responses to fire regimes varied with rainfall. Termites were sampled comprehensively during the wet season using cellulose baits and active searching in order to sample a variety of functional groups. 3. Assemblages differed significantly across savanna types with higher levels of diversity in the wetter site using the active searching method. Diversity was lowest at the most arid site but certain feeding groups (FGs) peaked in the savanna with intermediate rainfall. Differences between these savannas are attributed to broad underlying changes in net primary productivity and temperature, with mammalian herbivores thought to generate a peak in diversity of some faunal groups at the intermediate savanna through their role in facilitating nutrient cycling. 4. Overall, termites were highly resistant to fire in all savanna types with little difference between fire regimes (season and frequency), but assemblage composition and some FGs were affected by burning.Differences between fire regimes were more pronounced with increasing rainfall. These differences are likely to be linked to changes in vegetation structure caused by fire, which are more significant in wet savannas. 5. Synthesis and applications. Our findings, along with those for other insect taxa, indicate limited support for the pyrodiversity-biodiversity hypothesis; this suggests that, at least for invertebrates, management regimes can be flexible, although more caution is advisable in wetter savannas.
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This study explores the long-term effects of fire treatments on biomass and nutrient pools in an open savanna from Central Brazil. Treatments included early, middle and late dry season burns every 2 years, a middle dry season burn every 4 years, and protection from fire on five 4-ha plots. We quantified aboveground biomass of graminoids and forbs/sub-shurbs, and their nutrient concentrations and stocks in both dry and wet seasons, and below-ground biomass down to 30-cm depth. We found strong differences between wet and dry season, with biomass and nutrient concentrations being highest in the wet season, across all fire treatments. Fire treatments had significant effects on plant nutrient stocks and root distribution, although total biomass was not affected. Concentrations of the most volatile nutrients (N, S, K and P) were higher in the herbaceous aboveground biomass of the quadrennial and the unburnt plots, suggesting that increases in fire frequency would reduce the amount of nutrients in aboveground
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Surveys over a period of 38 years have shown a rapid successional change in the remaining areas of cerrado vegetation in western São Paulo State. Cerradão (the dense, tall, forest form of cerrado (sensu lato)) and cerrado/Atlantic forest ecotonal vegetation have replaced more open forms (such as campo cerrado) during this period. An aerial photographic survey in 1962 showed 75% cerrado (sensu stricto), 16% campo cerrado, and only 9% cerradão, while a survey combining Landsat imaging of 1992 with aerial photography of 1984 gave 69%, 0.6%, and 30.5% respectively for the same physiognomies. Visiting 10% of the sites of the latter survey in 2000 showed that cerradão had become the dominant vegetation of 68% of them. In a particular 180 ha site in Assis municipality, cerradão increased from 12.0 to 41.4% of the area in 22 years. Reduction of anthropic pressures, such as fire and cattle-grazing, is considered responsible for these rapid changes. Conservation issues and research priorities related to these changes are discussed and proposed.
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In the Cerrado savannas from Brazil fire events are common and strongly influence the vegetation structure and, consequently, the associated small mammals. In this paper, we investigate changes in the structure of small mammal communities related to sites of different post-fire ages. Mammals were captured in similar Cerrado sites that differed in time since the last burn (1 to 26 yr). We sampled six sites in the wet season of 1997 (phase 1) and, three years later, six sites in the wet and dry seasons (phase 2). Six rodent species and four marsupials were captured. Community composition changed drastically as a function of time since fire. The diversity and abundance of small mammals reached maximum values in the early successional stages. The rodent Calomys tener was present only in early seral stages. The rodent Bolomys lasiurus was more frequent in mid-successional stages and decreased in later seral stages, and the rodent Oryzomys subflavus occupied all successional stages. The marsupial Gracilinanus agilis was dominant in the area that did not burn for at least 23 yr. Changes in composition of the community of small mammals were more accelerated in early successional stages, when there are more drastic vegetational changes. The ability of small mammals to cope with Cerrado fires and the great dissimilarity among post-burning seral stages suggest that a mosaic of areas representing different post-fire seral stages could increase the regional diversity of this group.
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Structural and floristic changes of a fire-protected cerrado sensu stricto are described over a 13-year period. The study site is located in a biological reserve (2,800ha) surrounded by large Pinus spp. and Eucalyptus spp. plantations (36,000ha), in southwestern Bahia, Brazil. The region occurs in the outer-core of the Cerrado domain, near the Cerrado-Caatinga ecotone, and is mainly occupied by pasture and cropland. Surveys were carried out in 1991 and 2004 in 13 permanent plots (20×50m). Stems with diameter ≥5cm at 0.30m above ground level were identified and measured. Floristic changes were significant (Sørensen´s index=0.45). Species number rose from 62 to 84 (35.48%). Alpha diversity increased significantly (P>0.001). New species migrated to the area, and there was an expansion of many fire-sensitive species. Woody layer expanded, increasing 19.09% in density and 14.93% in basal area. Diameter distributions followed a “reversed-j” pattern on both occasions, but differed (P>0.05) due to a significant increase in the first two size-classes, indicating a high recruitment. Community dynamics was high and had a positive balance between recruitment (3.72%yr−1) and mortality (1.93%yr−1). Conversely, mean annual increment was very small, 0.096cmyr−1 (SD=0.14; N=808). Most species, including many dominant ones, had a positive balance in favor of recruitment and low turnover, indicating that although species immigration rate is high (1.42sppha−1), structural changes in species composition happens at a much slower pace. The surrounding forest plantations are permeable and do not limit species immigration; and may be connecting the reserve with the larger neighboring natural fragments, providing an abundant source for diaspores, and possibly neutralizing any fragmentation effects. Succession is also influenced by the ecotonal condition. The structure and floristics of the cerrado sensu stricto at this site (under present climatic conditions) is fire-dependent.
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Fire occurrences and their sources were monitored in Emas National Park, Brazil (17°49′–18°28′S; 52°39′–53°10′W) from June 1995 to May 1999. The extent of burned area and weather conditions were registered. Forty-five fires were recorded and mapped on a GIS during this study. Four fires occurred in the dry winter season (June–August; 7,942 ha burned), all caused by humans; 10 fires occurred in the seasonally transitional months (May and September) (33,386 ha burned); 31 fires occurred in the wet season, of which 30 were caused by lightning inside the park (29,326 ha burned), and one started outside the park (866 ha burned). Wet season lightning fires started in the open vegetation (wet field or grassy savanna) at a flat plateau, an area that showed significantly higher fire incidence. On average, winter fires burned larger areas and spread more quickly, compared to lightning fires, and fire suppression was necessary to extinguish them. Most lightning fires were patchy and extinguished primarily by rain. Lightning fires in the wet season, previously considered unimportant episodes, were shown to be very frequent and probably represent the natural fire pattern in the region. Lightning fires should be regarded as ecologically beneficial, as they create natural barriers to the spread of winter fires. The present fire management in the park is based on the burning of preventive firebreaks in the dry season and exclusion of any other fire. This policy does not take advantage of the beneficial effects of the natural fire regime and may in fact reduce biodiversity. The results presented here stress the need for reevaluating present policies and management procedures concerning fire in cerrado conservation areas.
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Indigenous peoples have been using fire in the cerrado (savannas) of Brazil as a form of management for thousands of years, yet we have little information on why, when and how these fire practices take place. The aim of this paper was to explore the traditional use of fire as a management tool by the Krah indigenous group living in the north-eastern region of Tocantns state, Brazil. The results indicate that the Krah burn for a variety of reasons throughout the dry season, thereby producing a mosaic of burned and unburned patches in the landscape. The paper discusses this burning regime in the context of contemporary issues regarding fire management, and in the face of changing perceptions to fire by the Krah themselves.
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Theoretically, fire–tree cover feedbacks can maintain savanna and forest as alternative stable states. However, the global extent of fire-driven discontinuities in tree cover is unknown, especially accounting for seasonality and soils. We use tree cover, climate, fire, and soils data sets to show that tree cover is globally discontinuous. Climate influences tree cover globally but, at intermediate rainfall (1000 to 2500 millimeters) with mild seasonality (less than 7 months), tree cover is bimodal, and only fire differentiates between savanna and forest. These may be alternative states over large areas, including parts of Amazonia and the Congo. Changes in biome distributions, whether at the cost of savanna (due to fragmentation) or forest (due to climate), will be neither smooth nor easily reversible.