Forest fragmentation, climate change and understory fire regimes on the Amazonian landscapes of the Xingu headwaters

Soares‐Filho, Britaldo; Silvestrini, Rafaella Almeida; Nepstad, Daniel C.; Brando, Paulo M.; Rodrigues, Henrique; Alencar, Ane; Coe, Michael T.; Locks, Charton Jahn; Lima, Letícia Santos de; Hissa, Letícia de Barros Viana; Stickler, C.

doi:10.1007/s10980-012-9723-6

Cited by 61 publications

(49 citation statements)

References 46 publications

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“…Consequently, fuels along forest edges are expected to become drier, leading to increased fire intensity (34). Second, deforestation fragments the landscape, creating a greater perimeter of forest edges (35). Third, tree mortality associated with previous logging, fire, severe drought, or edge effects can contribute to coarse fuel loads for multiple years as the twigs and branches of standing dead trees gradually decay and fall to the ground.…”

Section: Resultsmentioning

confidence: 99%

“…By 2011, ∼8% of the region's forests were <100 m from a clearing. These deforestation-driven increases in forest edges (35) and regional temperatures are likely to act synergistically to increase the likelihood of high-intensity fires throughout much of the Xingu region.…”

Section: Resultsmentioning

confidence: 99%

“…To secure the integrity of Amazonian forests along the arc of deforestation, efforts to end deforestation in the Amazon must be accompanied by programs and policies that reduce the accidental spread of land management fires into neighboring forests and effectively control forest fires when started. Both of these changes in regional land management seem feasible (3,35), and several promising initiatives to reduce the probability of forest fires are already underway. Examples of recent efforts include (i) development of an early warning system to forecast the locations and intensities of fires (3); (ii) implementation of Brazilian federal and state policies to prevent and control forest fires (40); and (iii) creation of volunteer fire brigades to fight fires within private farms and indigenous reserves (14,35,40).…”

Section: Resultsmentioning

confidence: 99%

“…Both of these changes in regional land management seem feasible (3,35), and several promising initiatives to reduce the probability of forest fires are already underway. Examples of recent efforts include (i) development of an early warning system to forecast the locations and intensities of fires (3); (ii) implementation of Brazilian federal and state policies to prevent and control forest fires (40); and (iii) creation of volunteer fire brigades to fight fires within private farms and indigenous reserves (14,35,40). Over a longer time horizon, the future of many forests in the region will require successful mitigation of greenhouse gas emissions to reduce the likelihood of extreme weather events.…”

Section: Resultsmentioning

confidence: 99%

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Abrupt increases in Amazonian tree mortality due to drought–fire interactions

Brando

Balch

Nepstad

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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669

710

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Interactions between climate and land-use change may drive widespread degradation of Amazonian forests. High-intensity fires associated with extreme weather events could accelerate this degradation by abruptly increasing tree mortality, but this process remains poorly understood. Here we present, to our knowledge, the first field-based evidence of a tipping point in Amazon forests due to altered fire regimes. Based on results of a large-scale, longterm experiment with annual and triennial burn regimes (B1yr and B3yr, respectively) in the Amazon, we found abrupt increases in fire-induced tree mortality (226 and 462%) during a severe drought event, when fuel loads and air temperatures were substantially higher and relative humidity was lower than long-term averages. This threshold mortality response had a cascading effect, causing sharp declines in canopy cover (23 and 31%) and aboveground live biomass (12 and 30%) and favoring widespread invasion by flammable grasses across the forest edge area (80 and 63%), where fires were most intense (e.g., 220 and 820 kW·m −1 ). During the droughts of 2007 and 2010, regional forest fires burned 12 and 5% of southeastern Amazon forests, respectively, compared with <1% in nondrought years. These results show that a few extreme drought events, coupled with forest fragmentation and anthropogenic ignition sources, are already causing widespread fire-induced tree mortality and forest degradation across southeastern Amazon forests. Future projections of vegetation responses to climate change across drier portions of the Amazon require more than simulation of global climate forcing alone and must also include interactions of extreme weather events, fire, and land-use change.forest dieback | fireline intensity | stable states | MODIS | fire mapping

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Abrupt increases in Amazonian tree mortality due to drought–fire interactions

Brando

Balch

Nepstad

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

669

710

View full text Add to dashboard Cite

show abstract

“…The link between drought severity, fuel availability, and fire activity has created optimal conditions for mega-fires in the eastern Amazon (Aragão et al, 2018). As the eastern Amazon exhibits some of the highest densities of ADE sites in the Amazon (Sombroek, 1966;Woods and McCann, 1999;Nimuendajú, 2004;Schaan, 2012;Stenborg et al, 2012), the abundance of more fire-prone ADE forests, coupled with the projected increase in the length and severity of the dry season driven by increasing ENSO activity (Cochrane et al, 1999a;Alencar et al, 2006Alencar et al, , 2015Soares-Filho et al, 2012), make the eastern Amazon extremely vulnerable to drought induced fire activity. During pre-Columbian times, periodic, low-severity fires were likely used to clear out much of the forest understory fuels for crop cultivation, leaving edible trees unaffected, while also reducing the risk of high-severity fires.…”

Section: Implications For Modern Fire Management In Ade Forestsmentioning

confidence: 99%

New Insights From Pre-Columbian Land Use and Fire Management in Amazonian Dark Earth Forests

et al. 2018

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Anthropogenic climate change driven by increased carbon emissions is leading to more severe fire seasons and increasing the frequency of mega-fires in the Amazon. This has the potential to convert Amazon forests from net carbon sinks to net carbon sources. Although modern human influence over the Earth is substantial, debate remains over when humans began to dominate Earth's natural systems. To date, little is known about the history of human land use in key regions like the Amazon. Here, we examine the history of human occupation from a ∼8,500 year-old sediment core record from Lake Caranã (LC) in the eastern Amazon. The onset of pre-Columbian activity at LC (∼4,500 cal yr B.P.) is associated with the beginning of fire management and crop cultivation, later followed by the formation of Amazonian Dark Earth soils (ADEs) ∼2,000 cal yr B.P. Selective forest enrichment of edible plants and low-severity fire activity altered the composition and structure of forests growing on ADEs (ADE forests) making them more drought susceptible and fire-prone. Following European colonization (1661 A.D.), the Amazon rubber boom (mid-1800s to 1920 A.D.) is associated with record-low fire activity despite drier regional climate, indicating fire exclusion. The formation of FLONA Reserve in 1974 A.D. is accompanied by the relocation of traditional populations and a fire suppression policy. Despite suppression efforts, biomass burning and fire severity in the past decade is higher than any other period in the record. This is attributed to combined climate and human factors which create optimal conditions for mega-fires in ADE forests and threatens to transform the Amazon from a net carbon sink to a net carbon source. To help mitigate the occurrence of mega-fires, a fire management policy reducing fire-use and careful fire management for farming may help to reduce fuel loads and the occurrence of mega-fires in fire-prone ADE forests. As both natural and anthropogenic pressures are projected to increase in the Amazon, this study provides valuable insights into the legacy of past human land use on modern ADE forest composition, structure, and flammability that can inform ecological benchmarks and future management efforts in the eastern Amazon.

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Integrating remotely sensed fires for predicting deforestation for REDD+

Armenteras

Gibbes

Anaya

et al. 2017

Ecological Applications

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Fire is an important tool in tropical forest management, as it alters forest composition, structure, and the carbon budget. The United Nations program on Reducing Emissions from Deforestation and Forest Degradation (REDD+) aims to sustainably manage forests, as well as to conserve and enhance their carbon stocks. Despite the crucial role of fire management, decision-making on REDD+ interventions fails to systematically include fires. Here, we address this critical knowledge gap in two ways. First, we review REDD+ projects and programs to assess the inclusion of fires in monitoring, reporting, and verification (MRV) systems. Second, we model the relationship between fire and forest for a pilot site in Colombia using near-real-time (NRT) fire monitoring data derived from the Moderate Resolution Imaging Spectroradiometer (MODIS). The literature review revealed fire remains to be incorporated as a key component of MRV systems. Spatially explicit modeling of land use change showed the probability of deforestation declined sharply with increasing distance to the nearest fire the preceding year (multi-year model area under the curve [AUC] 0.82). Deforestation predictions based on the model performed better than the official REDD early-warning system. The model AUC for 2013 and 2014 was 0.81, compared to 0.52 for the early-warning system in 2013 and 0.68 in 2014. This demonstrates NRT fire monitoring is a powerful tool to predict sites of forest deforestation. Applying new, publicly available, and open-access NRT fire data should be an essential element of early-warning systems to detect and prevent deforestation. Our results provide tools for improving both the current MRV systems, and the deforestation early-warning system in Colombia.

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Forest fragmentation, climate change and understory fire regimes on the Amazonian landscapes of the Xingu headwaters

Cited by 61 publications

References 46 publications

Abrupt increases in Amazonian tree mortality due to drought–fire interactions

Abrupt increases in Amazonian tree mortality due to drought–fire interactions

New Insights From Pre-Columbian Land Use and Fire Management in Amazonian Dark Earth Forests

Integrating remotely sensed fires for predicting deforestation for REDD+

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