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Journal ArticleDOI: 10.1016/J.JENVMAN.2021.112189

Burning in southwestern Brazilian Amazonia, 2016-2019.

04 Mar 2021-Journal of Environmental Management (Academic Press)-Vol. 286, pp 112189-112189
Abstract: Fire is one of the most powerful modifiers of the Amazonian landscape and knowledge about its drivers is needed for planning control and suppression. A plethora of factors may play a role in the annual dynamics of fire frequency, spanning the biophysical, climatic, socioeconomic and institutional dimensions. To uncover the main forces currently at play, we investigated the area burned in both forested and deforested areas in the outstanding case of Brazil's state of Acre, in southwestern Amazonia. We mapped burn scars in already-deforested areas and intact forest based on satellite images from the Landsat series analyzed between 2016 and 2019. The mapped burnings in already-deforested areas totalled 550,251 ha. In addition, we mapped three forest fires totaling 34,084 ha. Fire and deforestation were highly correlated, and the latter occurred mainly in federal government lands, with protected areas showing unprecedented forest fire levels in 2019. These results indicate that Acre state is under increased fire risk even during average rainfall years. The record fires of 2019 may continue if Brazil's ongoing softening of environmental regulations and enforcement is maintained. Acre and other Amazonian states must act quickly to avoid an upsurge of social and economic losses in the coming years.

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Topics: Deforestation (52%)
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7 results found


Open accessJournal ArticleDOI: 10.33448/RSD-V10I7.16612
Abstract: O surgimento de incendios florestais pode ser de origem antropica ou natural, ambas causam grandes prejuizos socioeconomico e ambiental, e em boa parte dessas ocorrencias sao resultantes da ocorrencia de Focos de Calor (FC). Nos ultimos anos, o Brasil tem sofrido com o aumento significativo de FC, ao qual resultaram em grandes incendios. Desta maneira, o objetivo do presente estudo foi diagnosticar o comportamento espaco-temporal dos FC no Brasil entre 1999 e 2020, baseados nos dados de dados BDQueimadas do CPTEC/INPE. Para a manipulacao e o processamento dos dados, utilizou-se o software de ambiente R versao 3.4-1. Apos o armazenamento dos dados, calculou-se os registros totais, medias anual e mensal, e a composicao dos anos mais significativos, neste caso, os anos de 2015, 2017, 2019 e 2020. Os resultados apontaram que os maiores acumulados totais e medios anuais variaram entre 10-50 mil FC e 0,5-1,5 mil FC, concentrados na regiao centro-norte do Brasil, principalmente nos estados do Maranhao, Para e Tocantins. Este padrao de alto registros de FC esta relacionado ao desmatamento e expansao agricola nessas regioes. Em escala mensal, as maiores ocorrencias de FC ocorrem entre os meses de agosto e novembro, com valores de 0,20-0,45 mil FC, devido ao periodo de estiagem. Verificou-se que nos ultimos anos, o El Nino-Oscilacao Sul influenciou a incidencia dos FC atraves da persistencia de longos periodos de estiagem, que resultaram em escassez de chuvas e grandes incendios verificados em 2020 no bioma Pantanal.

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2 Citations


Open accessJournal ArticleDOI: 10.3390/EARTH2020018
16 Jun 2021-Eearth
Abstract: Hydroelectric dams are a major threat to rivers in the Amazon. They are known to decrease river connectivity, alter aquatic habitats, and emit greenhouse gases such as carbon dioxide and methane. Multiscale remotely sensed data can be used to assess and monitor hydroelectric dams over time. We analyzed the Sinop dam on the Teles Pires river from high spatial resolution satellite imagery to determine the extent of land cover inundated by its reservoir, and subsequent methane emissions from TROPOMI S-5P data. For two case study areas, we generated 3D reconstructions of important endemic fish habitats from unmanned aerial vehicle photographs. We found the reservoir flooded 189 km2 (low water) to 215 km2 (high water) beyond the extent of the Teles Pires river, with 13–30 m tall forest (131.4 Mg/ha average AGB) the predominant flooded class. We further found the reservoir to be a source of methane enhancement in the region. The 3D model showed the shallow habitat had high complexity important for ichthyofauna diversity. The distinctive habitats of rheophile fishes, and of the unique species assemblage found in the tributaries have been permanently modified following inundation. Lastly, we illustrate immersive visualization options for both the satellite imagery and 3D products.

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Topics: Tributary (51%), Land cover (50%)

1 Citations


Open accessJournal ArticleDOI: 10.4038/CJS.V50I5.7921
Sumedha Madawala1, T. Wijewickrama1Institutions (1)
Abstract: Defying all norms of biological invasions, some native species expand their populations similar to their exotic counterparts causing potentially harmful impacts in native habitats. Despite an early caution by ecologists, they are now recognized as ‘native invaders’. Though ‘native’ invaders may also incur harmful impacts similar to their ‘exotic’ counterparts, there are clear contrasts between them, thus demanding further studies to explore their life traits and cues that trigger their invasive traits. Among native invaders, bamboos are in the forefront due to their robust growth and resilience to harsh conditions. Also, it is a known fact that bamboo-dominated forests are on the increase globally while native forest are declining at a rapid rate. This review attempts to condense the current understanding of ‘native’ bamboos that spread in the Asia Pacific region with invasive potential and their short- and long-term ecological impacts. Possible environmental cues that may trigger their ‘invasive’ nature are also discussed. Of many, climate change seems to be the major driving force triggering their invasive behavior, though long-term studies are needed to ratify this link. Major challenges and knowledge gaps that hamper their control have also been deliberated. The evidence confirmed that native bamboos have the potential to incur negative impacts on ecology, social and economic aspects. However, their impacts are not always in parallel with that of ‘exotic’ invaders, thus cautioning any attempt of generalization. The lack of comprehensive research and historical information are considered as major impediments to identify suitable measures to manage them effectively. Further studies are mandatory to fill the existing knowledge gaps and to identify challenges to bring about effective management strategies to control ‘native’ bamboos with invasive potential.

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Open accessJournal ArticleDOI: 10.33448/RSD-V10I15.22619
Abstract: In 2020, a total of 3.9 million hectares were burned in the Pantanal biome, which represents approximately 30% of its total area. Of the three existing biomes in the state of Mato Grosso, the Pantanal was the most impacted and, among all the municipalities in Mato Grosso, Pocone had the largest burned area. We aimed to characterize the areas affected by fires in the municipality of Pocone in 2020 to support prevention and adaptation actions in future scenarios. For this, we used the mapping of areas affected by fires made from the detections of active fire collected by the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor and available by the Global Fire Emissions Database (GFED). The results showed that a total of 869,170 hectares were burned in Pocone in 2020. Of this total, 97.3% were in natural areas, viz. forest formations (37%), savanna (2.8%), grassland formations (23.4%), wetlands (29.7%), and vegetation in dried-up rivers and lakes (4.4%). Concerning land categories, almost half of the fires occurred in private rural properties registered in the Rural Environmental Registry (CAR). In this scenario, we highlighted the importance of monitoring fires and holding those responsible for them accountable. It is also important to implement preventive actions in synergy with managers and local communities as a way of adapting to the climate crisis, intense drought, and less water surface available in the region, which increases the risk and damage of fires.

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Open accessJournal ArticleDOI: 10.3390/RS13122238
08 Jun 2021-Remote Sensing
Abstract: Canopy dynamics associated with fires in tropical forests play a critical role in the terrestrial carbon cycle and climate feedbacks. The aim of this study was to characterize forest canopy dynamics in the southern Amazon during the 2019 fire season (July–October) using passive microwave-based vegetation optical depth (VOD) and three optical-based indices. First, we found that precipitation during July–October 2019 was close to the climatic means, suggesting that there were no extreme hydrometeorological events in 2019 and that fire was the dominant factor causing forest canopy anomalies. Second, based on the active fire product (MCD14ML), the total number of active fires over each grid cell was calculated for each month. The number of active fires during the fire season in 2019 was above average, particularly in August and September. Third, we compared the anomalies of VOD and optical-based indices (the normalized difference vegetation index (NDVI), the enhanced vegetation index (EVI), and the normalized burn ratio (NBR)) against the spatiotemporal distribution of fires during July–October 2019. Spatially, the location with a concentrated distribution of significant negative VOD anomalies was matched with the grid cells with fire activities, whereas the concentrated distribution of strong negative anomalies in optical-based indices were found in both burned and unburned grid cells. When we focused on the temporal pattern over the grid cells with fire activity, the VOD and the optical-based indices behaved similarly from July to October 2019, i.e., the magnitude of negative anomalies became stronger with increased fire occurrences and reached the peak of negative anomalies in September before decreasing in October. A discrepancy was observed in the magnitude of negative anomalies of the optical-based indices and the VOD; the magnitude of optical-based indices was larger than the VOD in August–September and recovered much faster than the VOD over the grid cells with relatively low fire activity in October. The most likely reason for their different responses is that the VOD represents the dynamics of both photosynthetic (leaf) and nonphotosynthetic (branches) biomass, whereas optical-based indices are only sensitive to photosynthetic (leaf) active biomass, which recovers faster. Our results demonstrate that VOD can detect the spatiotemporal of canopy dynamics caused by fire and postfire canopy biomass recovery over high-biomass rainforest, which enables more comprehensive assessments, together with classic optical remote sensing approaches.

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Journal ArticleDOI: 10.1111/J.1523-1739.2005.00697.X
Philip M. Fearnside1Institutions (1)
Abstract: Brazil's Amazon forest remained largely intact until the "modern" era of deforestation began with the inauguration of the Transamazon Highway in 1970. Amazonian deforestation rates have trended upward since 1991, with clearing proceeding at a variable but always rapid pace. Amazonian forests are cut for various reasons, but cattle ranching predominates. The large and medium-sized ranches account for about 70% of clearing activity. Profit from beef cattle is only one of the income sources that make deforestation profitable. Forest degradation results from logging, ground fires (facilitated by logging), and the effects of fragmentation and edge formation. Degradation contributes to forest loss. The impacts of deforestation include loss of biodiversity, reduced water cycling (and rainfall), and contributions to global warming. Strategies to slow deforestation include repression through licensing procedures, monitoring and fines. The severity of penalties for deforestation needs to be sufficient to deter illegal clearing but not so great as to be inapplicable in practice. Policy reform is also needed to address root causes of deforestation, including the role of clearing in establishing land claims for both small and large actors.

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Topics: Clearing (53%), Logging (52%)

879 Citations


Journal ArticleDOI: 10.1126/SCIENCE.1200807
04 Feb 2011-Science
Abstract: In 2010, dry-season rainfall was low across Amazonia, with apparent similarities to the major 2005 drought. We analyzed a decade of satellite-derived rainfall data to compare both events. Standardized anomalies of dry-season rainfall showed that 57% of Amazonia had low rainfall in 2010 as compared with 37% in 2005 (≤-1 standard deviation from long-term mean). By using relationships between drying and forest biomass responses measured for 2005, we predict the impact of the 2010 drought as 2.2 × 10(15) grams of carbon [95% confidence intervals (CIs) are 1.2 and 3.4], largely longer-term committed emissions from drought-induced tree deaths, compared with 1.6 × 10(15) grams of carbon (CIs 0.8 and 2.6) for the 2005 event.

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871 Citations


Open accessJournal ArticleDOI: 10.1038/NATURE18326
Jos Barlow1, Jos Barlow2, Jos Barlow3, Gareth D. Lennox2  +35 moreInstitutions (16)
07 Jul 2016-Nature
Abstract: Concerted political attention has focused on reducing deforestation, and this remains the cornerstone of most biodiversity conservation strategies. However, maintaining forest cover may not reduce anthropogenic forest disturbances, which are rarely considered in conservation programmes. These disturbances occur both within forests, including selective logging and wildfires, and at the landscape level, through edge, area and isolation effects. Until now, the combined effect of anthropogenic disturbance on the conservation value of remnant primary forests has remained unknown, making it impossible to assess the relative importance of forest disturbance and forest loss. Here we address these knowledge gaps using a large data set of plants, birds and dung beetles (1,538, 460 and 156 species, respectively) sampled in 36 catchments in the Brazilian state of Para. Catchments retaining more than 69–80% forest cover lost more conservation value from disturbance than from forest loss. For example, a 20% loss of primary forest, the maximum level of deforestation allowed on Amazonian properties under Brazil’s Forest Code, resulted in a 39–54% loss of conservation value: 96–171% more than expected without considering disturbance effects. We extrapolated the disturbance-mediated loss of conservation value throughout Para, which covers 25% of the Brazilian Amazon. Although disturbed forests retained considerable conservation value compared with deforested areas, the toll of disturbance outside Para’s strictly protected areas is equivalent to the loss of 92,000–139,000 km2 of primary forest. Even this lowest estimate is greater than the area deforested across the entire Brazilian Amazon between 2006 and 2015 (ref. 10). Species distribution models showed that both landscape and within-forest disturbances contributed to biodiversity loss, with the greatest negative effects on species of high conservation and functional value. These results demonstrate an urgent need for policy interventions that go beyond the maintenance of forest cover to safeguard the hyper-diversity of tropical forest ecosystems.

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Topics: Secondary forest (68%), Forest restoration (64%), Intact forest landscape (64%) ... read more

523 Citations


Open accessJournal ArticleDOI: 10.1029/2006GL028946
Abstract: [1] There has been an increasing awareness of the possibility of climate change causing increased drought frequency in Amazonia, with ensuing impacts on ecosystems and human populations. This debate has been brought into focus by the 1997/1998 and 2005 Amazonian droughts. We analysed the spatial extent of these droughts and fire response to the 2005 drought with TRMM and NOAA-12 data, respectively. Both droughts had distinct fingerprints. The 2005 drought was characterized by its intensification throughout the dry season in south-western Amazonia. During 2005 the annual cumulative number of hot pixels in Amazonia increased 33% in relation to the 1999–2005 mean. In the Brazilian state of Acre, at the epicentre of the 2005 drought, the area of leakage forest fires was more than five times greater than the area directly deforested. Fire leakage into flammable forests may be the major agent of biome transformation in the event of increasing drought frequency.

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395 Citations


Open accessJournal ArticleDOI: 10.1073/PNAS.1302584110
Rong Fu1, Lei Yin1, Wenhong Li2, Paola A. Arias3  +7 moreInstitutions (7)
Abstract: We have observed that the dry-season length (DSL) has increased over southern Amazonia since 1979, primarily owing to a delay of its ending dates (dry-season end, DSE), and is accompanied by a prolonged fire season. A poleward shift of the subtropical jet over South America and an increase of local convective inhibition energy in austral winter (June–August) seem to cause the delay of the DSE in austral spring (September–November). These changes cannot be simply linked to the variability of the tropical Pacific and Atlantic Oceans. Although they show some resemblance to the effects of anthropogenic forcings reported in the literature, we cannot attribute them to this cause because of inadequate representation of these processes in the global climate models that were presented in the Intergovernmental Panel on Climate Change’s Fifth Assessment Report. These models significantly underestimate the variability of the DSE and DSL and their controlling processes. Such biases imply that the future change of the DSE and DSL may be underestimated by the climate projections provided by the Intergovernmental Panel on Climate Change’s Fifth Assessment Report models. Although it is not clear whether the observed increase of the DSL will continue in the future, were it to continue at half the rate of that observed, the long DSL and fire season that contributed to the 2005 drought would become the new norm by the late 21st century. The large uncertainty shown in this study highlights the need for a focused effort to better understand and simulate these changes over southern Amazonia.

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Topics: Climate change (55%)

313 Citations


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