Calibrating microcharcoal in recent marine sediments: implications to reconstruct paleofire regimes on African continent

2021 ◽  
Author(s):  
Aritina Haliuc ◽  
Anne-Laure Daniau ◽  
Braise team members
Keyword(s):  
Marine Sediments ◽  
Biomass Burning ◽  
Environmental Changes ◽  
Fire Regime ◽  
Regional Scale ◽  
Source Area ◽  
Fire Regimes ◽  
Integrated Approach ◽  
Burned Area ◽  
Marine Realm

<p>Fire is a worldwide terrestrial process and has shaped the ecosystems and life on Earth over millions of years. Today, fire regime metrics such as burned area, intensity and frequency, depend on a set of climatic and environmental variables, but under anticipated climate warming scenarios, it is projected that fire characteristics will change, posing great threats to the environment and society. Large uncertainties remain in better understanding this complex process, integrating it in Earth system global models and better forecasting the response of fire to future climate changes.</p><p>Paleofire records from marine sediments capture information about regional-scale relative changes in biomass burning over long timescale and can help understanding the relationships between climate change and fire activity. We still lack, though, what a change in biomass burning in the paleorecord means in terms of fire regimes.</p><p>The present study aims at exploring the link between charcoal accumulation in marine surface sediment samples of modern ages from about 150 sites across the African coast and fire regimes on land. It is based on an integrated approach using fire proxy, climate, environmental and historical information, and satellite data. Exploratory in character, this study is designed to investigate this link among different biomes, describing latitudinal and longitudinal transects, and to test the influence of different physical site-specific variables (climate, vegetation, size of the source area etc.) on land and transport-deposition processes into the marine realm.</p><p>This study aims to provide a novel sediment-based proxy for a key physical parameter unlocking specific technical and theoretical problems related to fire research; it may also help to better understand local to regional processes controlling the fire signal and contextualize current and past environmental changes.</p>

Planned and unplanned fire regimes on public land in south-east Queensland

2020 ◽  
Vol 29 (5) ◽  
pp. 326 ◽  
Author(s):  
Martyn Eliott ◽  
Tom Lewis ◽  
Tyron Venn ◽  
Sanjeev Kumar Srivastava
Keyword(s):  
Fire History ◽  
Fire Regime ◽  
Regional Scale ◽  
Fire Regimes ◽  
The Public ◽  
Asset Protection ◽  
Occurrence Data ◽  
The Individual ◽  
Service State ◽  
Open Forests

Land management agencies in Queensland conduct planned burning for a variety of reasons, principally for management of fuels for human asset protection and biodiversity management. Using Queensland Parks and Wildlife Service’s archived manually derived fire reports, this study considered the individual components of the fire regime (extent, frequency and season) to determine variation between planned and unplanned fire regimes in south-east Queensland. Overall, between 2004 and 2015, planned fire accounted for 31.6% and unplanned fire 68.4% of all fire on Queensland Parks and Wildlife Service state-managed land. Unplanned fire was more common in spring (September–October), and planned fire was more common in winter (June–August). Unplanned fire affected 71.4% of open forests and woodlands (148563ha), whereas 58.8% of melaleuca communities (8016ha) and 66.6% of plantations (2442ha) were burnt with planned fire. Mapping fire history at a regional scale can be readily done with existing publicly available datasets, which can be used to inform the assessment of planned burning effectiveness for human asset protection and the management of biodiversity. Fire management will benefit from the continued recording of accurate fire occurrence data, which allows for detailed fire regime mapping and subsequent adaptive management of fire regimes in the public domain.

The reconstruction of burned area and fire severity using charcoal from boreal lake sediments

The Holocene ◽  
2020 ◽  
Vol 30 (10) ◽  
pp. 1400-1409 ◽  
Author(s):  
Andy Hennebelle ◽  
Julie C Aleman ◽  
Adam A Ali ◽  
Yves Bergeron ◽  
Christopher Carcaillet ◽  
...  
Keyword(s):  
Lake Sediments ◽  
Surface Area ◽  
Fire Severity ◽  
Source Area ◽  
Fire Regimes ◽  
Burned Area ◽  
Median Surface ◽  
Landsat Images ◽  
Eastern Canada ◽  
Lag Effects

Although lacustrine sedimentary charcoal has long been used to infer paleofires, their quantitative reconstructions require improvements of the calibration of their links with fire regimes (i.e. occurrence, area, and severity) and the taphonomic processes that affect charcoal particles between the production and the deposition in lake sediments. Charcoal particles >150 µm were monitored yearly from 2011 to 2016 using traps submerged in seven head lakes situated in flat-to-rolling boreal forest landscapes in eastern Canada. The burned area was measured, and the above-ground fire severity was assessed using the differentiated normalized burn ratio (dNBR) index, derived from LANDSAT images, and measurements taken within zones radiating 3, 15, and 30 km from the lakes. In order to evaluate potential lag effects in the charcoal record, fire metrics were assessed for the year of recorded charcoal recording (lag 0) and up to 5 years before charcoal deposition (lag 5). A total of 92 variables were generated and sorted using a Random Forest-based methodology. The most explanatory variables for annual charcoal particle presence, expressed as the median surface area, were selected. Results show that, temporally, sedimentary charcoal accurately recorded fire events without a temporal lag; spatially, fires were recorded up to 30 km from the lakes. Selected variables highlighted the importance of burned area and fire severity in explaining lacustrine charcoal. The charcoal influx was thus driven by fire area and severity during the production process. The dispersion process of particles resulted mostly of wind transportation within the regional (<30 km) source area. Overall, charcoal median surface area represents a reliable proxy for reconstructing past burned areas and fire severities.

Inter- and intra-annual profiles of fire regimes in the managed forests of Canada and implications for resource sharing

2012 ◽  
Vol 21 (4) ◽  
pp. 328 ◽  
Author(s):  
Steen Magnussen ◽  
Stephen W. Taylor
Keyword(s):  
Resource Sharing ◽  
Joint Distribution ◽  
Fire Management ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Season ◽  
Burned Area ◽  
Fire Activity ◽  
In Fire ◽  
Regional Synchrony

Year-to-year variation in fire activity in Canada constitutes a key challenge for fire management agencies. Interagency sharing of fire management resources has been ongoing on regional, national and international scales in Canada for several decades to better cope with peaks in resource demand. Inherent stressors on these schemes determined by the fire regimes in constituent jurisdictions are not well known, nor described by averages. We developed a statistical framework to examine the likelihood of regional synchrony of peaks in fire activity at a timescale of 1 week. Year-to-year variations in important fire regime variables and 48 regions in Canada are quantified by a joint distribution and profiled at the Provincial or Territorial level. The fire regime variables capture the timing of the fire season, the average number of fires, area burned, and the timing and extent of annual maxima. The onset of the fire season was strongly correlated with latitude and longitude. Regional synchrony in the timing of the maximum burned area within fire seasons delineates opportunities for and limitations to sharing of fire suppression resources during periods of stress that were quantified in Monte Carlo simulations from the joint distribution.

Predictive modelling of fire occurrences from different fire spread patterns in Mediterranean landscapes

2015 ◽  
Vol 24 (3) ◽  
pp. 407 ◽  
Author(s):  
Andrea Duane ◽  
Míriam Piqué ◽  
Marc Castellnou ◽  
Lluís Brotons
Keyword(s):  
Environmental Changes ◽  
Regional Scale ◽  
Fire Regimes ◽  
Fire Spread ◽  
Global Changes ◽  
Strong Impact ◽  
Relative Contribution ◽  
Mediterranean Landscapes ◽  
Temporal Validation ◽  
In Fire

Fire regimes are shifting worldwide because of global changes. The relative contribution of climate, topography and vegetation greatly determines spatial and temporal variations in fire regimes, but the interplay of these factors is not yet well understood. We introduce here a novel classification of fires according to dominant fire spread pattern, an approach considered in operational firefighting, to help understand regional-scale spatial variability in fire regimes. Here, we studied whether climate, topography and fuel variables allowed the prediction of occurrences from different fire spread patterns in Catalonia, NE Spain. We used a correlative modelling approach based on maximum entropy methods, and examined, through variation partitioning, the relative contribution of different factors on determining their occurrence. Our results accurately predicted the occurrence of different fire spread patterns, and the results were consistent when temporal validation was conducted. Although forest fuel factors made a higher contribution to the occurrence of convective fires, wind-driven fires were strongly related to topographic and climate factors. These findings may have a strong impact on investigations into how fire regimes may be projected into the future under forecast global change as they suggest that future environmental changes may affect different fire spread patterns in an idiosyncratic manner.

Future fires in the Coupled Model Intercomparison Project (CMIP) phase 6

2020 ◽  
Author(s):  
Gitta Lasslop ◽  
Stijn Hantson ◽  
Victor Brovkin ◽  
Fang Li ◽  
David Lawrence ◽  
...  
Keyword(s):  
Land Use ◽  
Fire Regime ◽  
Coupled Model ◽  
Fire Regimes ◽  
Atmospheric Composition ◽  
Cloud Formation ◽  
Burned Area ◽  
Earth System ◽  
System Models ◽  
Earth System Models

&lt;p&gt;Fires are an important component in Earth system models (ESMs), they impact vegetation carbon storage, vegetation distribution, atmospheric composition and cloud formation. The representation of fires in ESMs contributing to CMIP phase 5 was still very simplified. Several Earth system models updated their representation of fires in the meantime. Using the latest simulations of CMIP6 we investigate how fire regimes change in the future for different scenarios and how land use, climate and atmospheric CO&lt;sub&gt;2&lt;/sub&gt; concentration contribute to the fire regimes changes. We quantify changes in fire danger, burned area and carbon emissions on an annual and seasonal basis. Factorial model simulations allow to quantify the influence of land use, climate and atmospheric CO&lt;sub&gt;2&lt;/sub&gt; on fire regimes.&lt;/p&gt;&lt;p&gt;We complement the information on fire regime change supplied by ESMs that include a fire module with a statistical modelling approach for burned area. This will use information from simulated changes in climate, vegetation and socioeconomic changes (population density and land use) provided for a set of different future scenarios. This allows the integration of information provided by global satellite products on burned area with the process-based simulations of climate and vegetation changes and information from socioeconomic scenarios.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

scholarly journals A fire model with distinct crop, pasture, and non-agricultural burning: Use of new data and a model-fitting algorithm for FINALv1

2017 ◽  
Author(s):  
Sam S. Rabin ◽  
Sergey L. Malyshev ◽  
Brian I. Magi ◽  
Elena Shevliakova ◽  
Stephen W. Pacala
Keyword(s):  
Carbon Emissions ◽  
Regional Scale ◽  
Model Fitting ◽  
Fire Regimes ◽  
Optimization Method ◽  
Sub Saharan Africa ◽  
Burned Area ◽  
Pasture Management ◽  
Fire Models ◽  
Agricultural Burning

Abstract. This study describes and evaluates the Fire Including Natural &amp; Agricultural Lands model (FINAL) which, for the first time, explicitly simulates cropland and pasture management fires separately from non-agricultural fires. The non-agricultural fire module uses empirical relationships to simulate burned area in a quasi-mechanistic framework, similar to past fire modeling efforts, but with a novel optimization method that improves the fidelity of simulated fire patterns to new observational estimates of non-agricultural burning. The agricultural fire components are forced with estimates of cropland and pasture fire seasonality and frequency derived from observational land-cover and satellite fire datasets. FINAL accurately simulates the amount, distribution, and seasonal timing of burned cropland and pasture over 2001–2009 (global totals: 0.434 × 106 and 2.02 × 106 km2 yr−1 modeled, 0.454 × 106 and 2.04 × 106 km2 yr−1 observed), but carbon emissions for cropland and pasture fire are overestimated (global totals: 0.297 PgC yr−1 and 0.712 PgC yr−1 modeled, 0.194 PgC yr−1 and 0.538 PgC yr−1 observed). The non-agricultural fire module underestimates global burned area (1.66 × 106 km2 yr−1 modeled, 2.44 × 106 km2 yr−1 observed) and carbon emissions (1.33 PgC yr−1 modeled, 1.84 PgC yr−1 observed). The spatial pattern of total burned area and carbon emissions is generally well reproduced across much of sub-Saharan Africa, Brazil, central Asia, and Australia, whereas the boreal zone suffers from underestimates. FINAL represents an important step in the development of global fire models, and offers a strategy for fire models to consider human-driven fire regimes on cultivated lands. At the regional scale, simulations would benefit from refinements in the parameterizations and improved optimization datasets.

Fire regime from 1973 to 2011 in north-western Patagonian grasslands

2016 ◽  
Vol 25 (9) ◽  
pp. 922 ◽  
Author(s):  
Facundo José Oddi ◽  
Luciana Ghermandi
Keyword(s):  
Fire Regime ◽  
Terrestrial Ecosystems ◽  
Fire Regimes ◽  
Burned Area ◽  
General Knowledge ◽  
Fire Size ◽  
Socioeconomic Impacts ◽  
Mean Size ◽  
Fire Size Distribution ◽  
North Western

Fire is one of the most important disturbances in terrestrial ecosystems and has major ecological and socioeconomic impacts. Fire regime describes the variation of individual fire events in time and space. Few studies have characterised the fire regime in grasslands in spite of the importance of these ecosystems. The aim of this study was to describe the recent fire regime (from 1973 to 2011) of north-western Patagonian grasslands in terms of seasonality, frequency and burned area. Our study area covered 560 000 ha and we used a remote sensing approach combined with statistics obtained from operational databases. Fires occur during the summer in 2 of every 3 years with a frequency of 2.7 fires per year and a mean size of 823 ha. Fire size distribution is characterised by many small fires and few large ones which would respond to a distribution from the power law family. Eighty per cent of the total area affected by fire was burned in the span of a few years, which were also widespread fire years in forests and woodlands of north-western Patagonia. This work contributes to general knowledge about fire regimes in grasslands and we expect that our results will serve as a reference to further fire regime research.

scholarly journals Sensitivity of simulated historical burned area to environmental andanthropogenic controls: A comparison of seven fire models

2019 ◽  
Author(s):  
Lina Teckentrup ◽  
Sandy P. Harrison ◽  
Stijn Hantson ◽  
Angelika Heil ◽  
Joe R. Melton ◽  
...  
Keyword(s):  
Land Use ◽  
Global Change ◽  
Fire Regime ◽  
Fire Behavior ◽  
Fire Regimes ◽  
Burned Area ◽  
Strong Response ◽  
Fire Models ◽  
In Fire ◽  
The Impact

Abstract. Understanding how fire regimes change over time is of major importance for understanding their future impact on the Earth system, including society. Large differences in simulated burned area between fire models show that there is substantial uncertainty associated with modelling global change impacts on fire regimes. We draw here on sensitivity simulations made by seven global dynamic vegetation models participating in the Fire Model Intercomparison Project (FireMIP) to understand how differences in models translate into differences in fire regime projections. The sensitivity experiments isolate the impact of the individual drivers of fire, which are prescribed in the simulations. Specifically these drivers are atmospheric CO2, population density, land-use change, lightning and climate. The seven models capture spatial patterns in burned area. However, they show considerable differences in the burned area trends since 1900. We analyse the trajectories of differences between the sensitivity and reference simulation to improve our understanding of what drives the global trend in burned area. Where it is possible, we link the inter-model differences to model assumptions. Overall, these analyses reveal that the strongest differences leading to diverging trajectories are related to the way anthropogenic ignitions and suppression, as well as the effects of land-use on vegetation and fire, are incorporated in individual models. This points to a need to improve our understanding and model representation of the relationship between human activities and fire to improve our abilities to model fire for global change applications. Only two models show a strong response to CO2 and the response to lightning on global scale is low for all models. The sensitivity to climate shows a spatially heterogeneous response and globally only two models show a significant trend. It was not possible to attribute the climate-induced changes in burned area to model assumptions or specific climatic parameters. However, the strong influence of climate on the inter-annual variability in burned area, shown by all the models, shows that we need to pay attention to the simulation of fire weather but also meteorological influences on biomass accumulation and fuel properties in order to better capture extremes in fire behavior.

scholarly journals Wildfire history of the boreal forest of southwestern Yakutia (Siberia) over the last two millennia documented by a lake-sedimentary charcoal record

2020 ◽  
Author(s):  
Ramesh Glückler ◽  
Ulrike Herzschuh ◽  
Stefan Kruse ◽  
Andrei Andreev ◽  
Stuart Andrew Vyse ◽  
...  
Keyword(s):  
Boreal Forests ◽  
Environmental Changes ◽  
Fire Regime ◽  
Land Development ◽  
Fire Regimes ◽  
Tree Cover ◽  
Vegetation Composition ◽  
Climate Conditions ◽  
In Fire ◽  
The Last Two Millennia

Abstract. Wildfires, as a key disturbance in forest ecosystems, are shaping the world’s boreal landscapes. Changes in fire regimes are closely linked to a wide array of environmental factors, such as vegetation composition, climate change, and human activity. Arctic and boreal regions and, in particular, Siberian boreal forests are experiencing rising air and ground temperatures with the subsequent degradation of permafrost soils, leading to shifts in tree cover and species composition. Compared to the boreal zones of North America or Europe, little is known about how such environmental changes might influence long-term fire regimes in Russia. The larch-dominated eastern Siberian deciduous boreal forests differ markedly from the composition of other boreal forests, yet data about past fire regimes remain sparse. Here, we present a high-resolution macroscopic charcoal record from lacustrine sediments of Lake Khamra (SW Yakutia, Siberia) spanning the last c. 2200 years, including information about charcoal particle sizes and morphotypes. Our results reveal a phase of increased charcoal accumulation between 600–900 CE, indicative of relatively high amounts of burnt biomass and high fire frequencies. This is followed by an almost 900-year-long period of low charcoal accumulation without significant peaks, likely corresponding to cooler climate conditions. After 1750 CE fire frequencies and the relative amount of biomass burnt start to increase again, coinciding with a warming climate and increased anthropogenic land development after Russian colonisation. In the 20th century, total charcoal accumulation decreases again to very low levels, despite higher fire frequency, potentially reflecting a change in fire management strategies and/or a shift of the fire regime towards more frequent, but smaller fires. A similar pattern for different charcoal morphotypes and comparison to a pollen and non-pollen palynomorph record from the same sediment core indicate that broad-scale changes in vegetation composition were probably not a major driver of recorded fire regime changes. Instead, the fire regime of the last two millennia at Lake Khamra seems to be controlled mainly by a combination of short-term climate variability and anthropogenic fire ignition and suppression.

scholarly journals Humans take control of fire-driven diversity changes in Mediterranean Iberia’s vegetation during the mid–late Holocene

The Holocene ◽  
2019 ◽  
Vol 29 (5) ◽  
pp. 886-901 ◽  
Author(s):  
Simon E Connor ◽  
Boris Vannière ◽  
Daniele Colombaroli ◽  
R Scott Anderson ◽  
José S Carrión ◽  
...  
Keyword(s):  
Fire Regime ◽  
Regional Scale ◽  
Fire Regimes ◽  
Regime Shifts ◽  
Rate Of Change ◽  
Ecological Impacts ◽  
Primary Role ◽  
Vegetation Diversity ◽  
Human Environment ◽  
Regime Changes

Fire regime changes are considered a major threat to future biodiversity in the Mediterranean Basin. Such predictions remain uncertain, given that fire regime changes and their ecological impacts occur over timescales that are too long for direct observation. Here we analyse centennial- and millennial-scale shifts in fire regimes and compositional turnover to track the consequences of fire regime shifts on Mediterranean vegetation diversity. We estimated rate-of-change, richness and compositional turnover (beta diversity) in 13 selected high-resolution palaeoecological records from Mediterranean Iberia and compared these with charcoal-inferred fire regime changes. Event sequence analysis showed fire regime shifts to be significantly temporally associated with compositional turnover, particularly during the last three millennia. We find that the timing and direction of fire and diversity change in Mediterranean Iberia are best explained by long-term human–environment interactions dating back perhaps 7500 years. Evidence suggests that Neolithic burning propagated a first wave of increasing vegetation openness and promoted woodland diversity around early farming settlements. Landscape transformation intensified around 5500 to 5000 cal. yr BP and accelerated during the last two millennia, as fire led to permanent transitions in ecosystem state. These fire episodes increased open vegetation diversity, decreased woodland diversity and significantly altered richness on a regional scale. Our study suggests that anthropogenic fires played a primary role in diversity changes in Mediterranean Iberia. Their millennia-long legacy in today’s vegetation should be considered for biodiversity conservation and landscape management.

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