scholarly journals Is Anthropogenic Pyrodiversity Invisible in Paleofire Records?

Fire ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 42 ◽  
Author(s):  
Roos ◽  
Williamson ◽  
Bowman
Keyword(s):  
High Frequency ◽  
Landscape Heterogeneity ◽  
Fire Regime ◽  
Fire Regimes ◽  
Regime Shifts ◽  
Cultural Changes ◽  
Regime Changes ◽  
Other Information ◽  
Patch Burning ◽  
The Impact

Paleofire studies frequently discount the impact of human activities in past fire regimes. Globally, we know that a common pattern of anthropogenic burning regimes is to burn many small patches at high frequency, thereby generating landscape heterogeneity. Is this type of anthropogenic pyrodiversity necessarily obscured in paleofire records because of fundamental limitations of those records? We evaluate this with a cellular automata model designed to replicate different fire regimes with identical fire rotations but different fire frequencies and patchiness. Our results indicate that high frequency patch burning can be identified in tree-ring records at relatively modest sampling intensities. However, standard methods that filter out fires represented by few trees systematically biases the records against patch burning. In simulated fire regime shifts, fading records, sample size, and the contrast between the shifted fire regimes all interact to make statistical identification of regime shifts challenging without other information. Recent studies indicate that integration of information from history, archaeology, or anthropology and paleofire data generate the most reliable inferences of anthropogenic patch burning and fire regime changes associated with cultural changes.

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.

scholarly journals Climate, not Aboriginal landscape burning, controlled the historical demography and distribution of fire-sensitive conifer populations across Australia

2013 ◽  
Vol 280 (1773) ◽  
pp. 20132182 ◽  
Author(s):  
Shota Sakaguchi ◽  
David M. J. S. Bowman ◽  
Lynda D. Prior ◽  
Michael D. Crisp ◽  
Celeste C. Linde ◽  
...  
Keyword(s):  
Fire Regime ◽  
Fire Risk ◽  
Fire Regimes ◽  
Demographic Analysis ◽  
Distribution Models ◽  
Last Glacial ◽  
Regime Changes ◽  
Population Sizes ◽  
The Impact ◽  
The Last Glacial

Climate and fire are the key environmental factors that shape the distribution and demography of plant populations in Australia. Because of limited palaeoecological records in this arid continent, however, it is unclear as to which factor impacted vegetation more strongly, and what were the roles of fire regime changes owing to human activity and megafaunal extinction (since ca 50 kya). To address these questions, we analysed historical genetic, demographic and distributional changes in a widespread conifer species complex that paradoxically grows in fire-prone regions, yet is very sensitive to fire. Genetic demographic analysis showed that the arid populations experienced strong bottlenecks, consistent with range contractions during the Last Glacial Maximum ( ca 20 kya) predicted by species distribution models. In southern temperate regions, the population sizes were estimated to have been mostly stable, followed by some expansion coinciding with climate amelioration at the end of the last glacial period. By contrast, in the flammable tropical savannahs, where fire risk is the highest, demographic analysis failed to detect significant population bottlenecks. Collectively, these results suggest that the impact of climate change overwhelmed any modifications to fire regimes by Aboriginal landscape burning and megafaunal extinction, a finding that probably also applies to other fire-prone vegetation across Australia.

Effect of fire regime on the grass community of the humid savanna of Lamto, Ivory Coast

2018 ◽  
Vol 35 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Kouamé Fulgence Koffi ◽  
Aya Brigitte N’Dri ◽  
Jean-Christophe Lata ◽  
Souleymane Konaté ◽  
Tharaniya Srikanthasamy ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Ivory Coast ◽  
Fire Regime ◽  
Fire Regimes ◽  
Abundant Species ◽  
Grass Species ◽  
The Third ◽  
Humid Savanna ◽  
The Impact ◽  
Tussock Grasses

AbstractThis study assesses the impact of four fire treatments applied yearly over 3 y, i.e. early fire, mid-season fire, late fire and no fire treatments, on the grass communities of Lamto savanna, Ivory Coast. We describe communities of perennial tussock grasses on three replicated 5 × 5-m or 10 × 5-m plots of each fire treatment. Tussock density did not vary with fire treatment. The relative abundance of grass species, the circumference of grass tussocks and the probability of having a tussock with a central die-back, varied with fire treatment. Mid-season fire had the highest proportion of tussocks with a central die-back while the late fire had the smallest tussocks. Tussock density, circumference, relative abundance and probability of having a central die-back varied with species. Andropogon canaliculatus and Hyparrhenia diplandra were the most abundant of the nine grass species. They had the largest tussocks and the highest proportion of tussock with a central die-back. Loudetia simplex was the third most abundant species but was very rare in no fire plots. The distribution of tussock circumferences was right skewed and dominated by small tussocks. The proportion of the tussocks with a central die-back strongly increased with circumference, which could lead to tussock fragmentation. Taken together, this study suggests that fire regimes impact grass demography and that this impact depends on grass species and tussock size.

scholarly journals Potentials and limitations for human control over historic fire regimes in the boreal forest

2007 ◽  
Vol 363 (1501) ◽  
pp. 2351-2356 ◽  
Author(s):  
Anders Granström ◽  
Mats Niklasson
Keyword(s):  
Fire Regime ◽  
Fire Regimes ◽  
Fire Spread ◽  
Fire Frequency ◽  
Human Control ◽  
Regime Changes ◽  
Northern Fennoscandia ◽  
Potential Impact ◽  
Cattle Husbandry ◽  
Different Cultures

Fire, being both a natural and cultural phenomenon, presents problems in disentangling the historical effect of humans from that of climate change. Here, we investigate the potential impact of humans on boreal fire regimes from a perspective of fuels, ignitions and culture. Two ways for a low technology culture to impact the fire regime are as follows: (i) by altering the number of ignitions and their spatial distribution and timing and (ii) by hindering fire spread. Different cultures should be expected to have quite different impacts on the fire regimes. In northern Fennoscandia, there is evidence for fire regime changes associated with the following: a reindeer herding culture associated with few ignitions above the natural; an era of cattle husbandry with dramatically increased ignitions and somewhat higher fire frequency; and a timber exploitation era with decreasing fire sizes and diminishing fire frequency. In other regions of the boreal zone, such schemes can look quite different, but we suggest that a close look at the resource extraction and land use of different cultures should be part of any analysis of past fire regimes.

Fire history in ponderosa pine landscapes of Grand Canyon National Park: is it reliable enough for management and restoration?

2006 ◽  
Vol 15 (3) ◽  
pp. 433 ◽  
Author(s):  
William L. Baker
Keyword(s):  
Ponderosa Pine ◽  
National Park ◽  
Fire History ◽  
Fire Regime ◽  
Grand Canyon ◽  
Fire Risk ◽  
Fire Regimes ◽  
Grand Canyon National Park ◽  
High Severity ◽  
The Impact

Reconstructing fire regimes of the past can provide a valuable frame of reference for understanding the impact of human land uses on contemporary fire and forest structure, but methods for reconstructing past fire regimes are under re-evaluation. In the present article, a common method of characterizing surface fire regimes, using composite fire intervals from fire scars, is shown to significantly underestimate the length of the fire rotation and population mean fire interval in Grand Canyon landscapes where these parameters are known. Also, the evidence and interpretation that past high-severity fire was uncommon in ponderosa pine landscapes in Grand Canyon National Park are challenged. Together, these two concerns mean that an alternative characterization of the fire regime, which has very different implications, cannot be excluded. Management aimed at lowering fire risk, as a means of restoration, does not presently have a sound scientific basis, if it uses the composite fire interval as a measure of the fire regime or is based on fire history research that lacks adequate analysis of past high-severity fire.

scholarly journals Frequent fires prime plant developmental responses to burning

2019 ◽  
Vol 286 (1909) ◽  
pp. 20191315 ◽  
Author(s):  
Kimberley J. Simpson ◽  
Jill K. Olofsson ◽  
Brad S. Ripley ◽  
Colin P. Osborne
Keyword(s):  
Developmental Plasticity ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Fire Exposure ◽  
Regime Changes ◽  
Below Ground ◽  
Developmental Responses ◽  
In Fire ◽  
Plastic Responses

Coping with temporal variation in fire requires plants to have plasticity in traits that promote persistence, but how plastic responses to current conditions are affected by past fire exposure remains unknown. We investigate phenotypic divergence between populations of four resprouting grasses exposed to differing experimental fire regimes (annually burnt or unburnt for greater than 35 years) and test whether divergence persists after plants are grown in a common environment for 1 year. Traits relating to flowering and biomass allocation were measured before plants were experimentally burnt, and their regrowth was tracked. Genetic differentiation between populations was investigated for a subset of individuals. Historic fire frequency influenced traits relating to flowering and below-ground investment. Previously burnt plants produced more inflorescences and invested proportionally more biomass below ground, suggesting a greater capacity for recruitment and resprouting than unburnt individuals. Tiller-scale regrowth rate did not differ between treatments, but prior fire exposure enhanced total regrown biomass in two species. We found no consistent genetic differences between populations suggesting trait differences arose from developmental plasticity. Grass development is influenced by prior fire exposure, independent of current environmental conditions. This priming response to fire, resulting in adaptive trait changes, may produce communities more resistant to future fire regime changes.

scholarly journals Landscape-based fire scenarios and fire types in the Ayllón massif (Central Mountain Range, Spain), 19th and 20th centuries

2020 ◽  
Vol 46 (1) ◽  
pp. 103-126
Author(s):  
C.R. Sequeira ◽  
C. Montiel-Molina ◽  
F.C. Rego
Keyword(s):  
Forest Management ◽  
Fire History ◽  
Driving Forces ◽  
Fire Regime ◽  
Fire Regimes ◽  
Landscape Dynamics ◽  
Mountain Range ◽  
Regime Changes ◽  
Fire Scenarios ◽  
Fire Type

Wildfires have been a major landscape disturbance factor throughout history in inland mountain areas of Spain. This paper aims to understand the interaction of fire regimes and landscape dynamics during the last two centuries within a socio-spatial context. The study area selected for this historical and spatial analysis is the Ayllón massif, in the Central Mountain Range. The theoretical background used to identify the driving forces of fire regime changes over the 19th and 20th centuries in this mountain area includes landscape-based fire scenarios and fire-type concepts. Both concepts have been addressed in recent studies from a spatial planning and fire management approach in an attempt to understand current fire landscapes and wildfire risk. However, this is the first time that these concepts have been applied to show that both spatial and temporal scales are crucial for an understanding of the current wildfire panorama, and that fire history related to landscape dynamics is fundamental in socio-spatial differences in fire regimes.Four variables (fire history, land use, population and settlement system, and forest management) were assessed to define historical landscape-based fire scenarios, and three fire feature variables (fire extent, fire cause, and spatial distribution pattern) were considered to define historical fire-types. We found that the non-linear evolution of fire regimes during the 19th and 20th centuries was determined by fire-type changes according to landscape dynamics. Moreover, population and forest management have been the main driving forces of fire regime tipping points or pyrotransitions. This study validates the hypothesis that fire regime changes are the result of the interaction of fire history and landscape dynamics.

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 Is cattle grazing more important than landscape heterogeneity for grasshoppers in Afromontane grassland?

2018 ◽  
Vol 27 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Lize Joubert-Van der Merwe ◽  
James S. Pryke
Keyword(s):  
Vegetation Cover ◽  
Landscape Heterogeneity ◽  
Fire Regime ◽  
Grazing Intensity ◽  
Local Environment ◽  
Fire Regimes ◽  
Bare Ground ◽  
Grasshopper Species ◽  
Rare Endemic ◽  
Landscape Attributes

Overgrazing is a major driver of habitat degradation, especially in southern Africa. Although grasshoppers are adapted to and benefit from natural disturbances, such as grazing by indigenous game and burning, we do not know how they respond to heavy cattle grazing, and how this response interacts with different fire regimes. We also do not know whether grasshoppers respond principally to these disturbances, to changes in the vegetation layer, or to larger landscape attributes (e.g. elevation). We addressed these questions in the topographically heterogeneous Central Midlands of KwaZulu-Natal Province, South Africa. We compared grasshopper assemblages among sites differing in grazing intensity (light, moderate and heavy), fire regime, rocky outcrops and vegetation structure, and attributes of landscape heterogeneity. The local environment (rocky outcrops, bare ground cover, grass height and total vegetation cover) was more important than landscape attributes for all measures of diversity. Grasshopper species richness was best explained by grazing intensity, with the specific response determined by fire regime. Greatest species richness was consistently recorded in heavily-grazed grassland. Thus, we found no evidence in support of the Intermediate Disturbance Hypothesis. Grasshopper assemblage composition of areas with light grazing was different from those with heavy grazing, but areas with light grazing were similar to those with moderate grazing under all fire regimes. Different suites of grasshopper species were adapted to changes in the local environment, with greatest diversity (Shannon H’) associated with elevated levels of bare ground and sparse vegetation cover. The greatest proportion of rare, endemic and sensitive grasshoppers (incl. Lentula minuta, Machaeridia conspersa and Qachasia fastigiata) was associated with a greater proportion of vegetation cover. The sensitivity of grasshopper assemblages to fire-grazing interactions, and the habitat requirements of different suites of species necessitates consideration of different types (fire and grazing) as well as levels of disturbances when adjusting management practices. We recommend that conservation of rare, endemic and sensitive grasshoppers should be prioritized, as these are most vulnerable to local extirpation.

Global distribution and temporal patterns of fire on peatlands

2020 ◽  
Author(s):  
Farina de Waard ◽  
Alexandra Barthelmes ◽  
Hans Joosten
Keyword(s):  
Ecosystem Services ◽  
North America ◽  
Land Reclamation ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Occurrence ◽  
Tropical Regions ◽  
In Fire ◽  
Peat Fires ◽  
The Impact

<p>Peatland ecosystems provide critical ecosystem-services such as water and carbon storage and harbor unique biodiversity. Once ignited, peat fires may burn uncontrollably for weeks or months resulting in rapid ecosystem degradation and excessive CO<sub>2</sub>- Emissions. Despite the impact of peat fires on ecosystem services and climate, peatland fire regimes remain poorly characterized for many parts of the world. Here we investigate the global occurrence of peatland fires over the last two decades.</p><p>We estimate the global extent of peatland fires from 2009 to 2018 and identify drivers of variability and trends using a global peatland map (Global Peatland Database /Greifswald Mire Centre 2019), active fire detections from the Moderate Resolution imaging Spectroradiometer (MODIS), and several fire regime and climate anomaly-datasets. The data were used to delineate 14 ‘Peatland Fire Regions’ (PFR).</p><p>Our results indicate that between 2009 and 2018 globally 553,950 km² of peatland have been affected by fire (7.88 % of the global peatland area), whereas patterns and trends are widely differing. The extent of fire-affected area in the PFRs of Boreal North America and Boreal Eurasia both exceeded 80,000 km², which for both areas accounts for ~3.5 % of the peatland area. In the same time, over 120,000 km² were affected in both Central Asia and Equatorial Asia, i.e. ~23 % of their respective peatland area.</p><p>Northern peatlands are rather subject to natural fires and fire incidence is mostly driven by climate anomalies like droughts. Large peaks in fire occurrence in Boreal North America and Boreal Eurasia were correlated with higher temperatures and less rain. The strong linkage of inter-annual fire variability to temperature anomalies suggests that in these regions fire frequency and intensity may increase in future.</p><p>In tropical regions, particularly those of Africa and Asia, peatland fires tended to occur on degraded peatlands and fires occurred often multiple times on the same site during our study period. While inter-annual variability in fire occurrence was strongly determined by climate, the long term trends in these regions are dominated by human land management. In Africa the fire affected peatland area was rather constant over the years and fires had the highest return frequency, which reflects the widespread culture of burning in land reclamation and agriculture.</p><p>Southern/Equatorial Asia and to some extent South America showed peaks correlated with ENSO associated drought events, leading to the largest fire-affected peatland area in just one year in the Equatorial Asia region of 50,900 km² (in 2015).</p>

Sign in / Sign up

Export Citation Format

Share Document