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opencc-by-4.0Oct 2023View details →

Plant life history data as evidence of an historical mixed-severity fire regime in Banksia woodlands

Context: The concept of the fire regime serves as an agreed upon template by which to inform understanding and management of fire-prone ecosystems globally. While observations from satellite imagery or palaeoecological proxy data can provide direct evidence of past fire regimes, they may be limited in temporal and/or spatial scale and are not available for all ecosystems. However, fire-related plant trait and demographic data offers an alternative approach to understand species-fire regime associations at the ecosystem scale. Aims: We aimed to quantify the life history strategies and associated fire regimes for six co-occurring shrub and tree species from fire-prone, Mediterranean climate Banksia woodlands in southwestern Australia. Methods: We collected static demographic data on size structure, seedling recruitment, and plant mortality across sites of varying time since last fire. We combined demographic data with key fire-related species traits to define plant life history strategies. We then compared observed life histories with a priori expectations for surface, stand-replacing, and mixed-severity fire regime types to infer historical fire regime associations.Key results: Fire-killed shrubs and weakly serotinous trees had abundant post-fire seedling recruitment, but also developed multi-cohort populations during fire-free periods via inter-fire seedling recruitment. Resprouting shrubs had little seedling recruitment at any time, even following fire, and showed no signs of decline in the long absence of fire likely due to their very long lifespans. Conclusions: The variation in life history strategies for these six co-occurring species is consistent with known ecological strategies to cope with high variation in fire intervals in a mixed-severity fire regime. While resprouting and strong post-fire seedling recruitment indicate a tolerance of frequent fire, inter-fire recruitment and weak serotiny is interpreted as a bet-hedging strategy to cope with occasional long fire-free periods that may otherwise exceed adult and seed bank lifespans. Implications: Our findings suggest that Banksia woodlands have evolved with highly variable fire intervals in a mixed-severity fire regime. Further investigations of species adaptations to varying fire size and patchiness can help extend our understanding of fire regime tolerances.

opencc-by-4.0Nov 2023View details →

Global seed dormancy patterns are driven by macroclimate but not fire regime

<ul><li>Seed dormancy maximizes plant recruitment in habitats with variation in environmental suitability for seedling establishment. Yet, we still lack a comprehensive synthesis of the macroecological drivers of nondormancy and the different classes of seed dormancy: physiological dormancy, morphophysiological dormancy and physical dormancy.</li><li>We examined current geographic patterns and environmental correlates of global seed dormancy variation. Combining the most updated data set on seed dormancy classes for > 10 000 species with > 4 million georeferenced species occurrences covering all of the world's biomes, we test how this distribution is driven by climate and fire regime.</li><li>Seed dormancy is prevalent in seasonally cold and dry climates. Physiological dormancy occurs in relatively dry climates with high temperature seasonality (e.g. temperate grasslands). Morphophysiological dormancy is more common in forest-dominated, cold biomes with comparatively high and evenly distributed precipitation. Physical dormancy is associated with dry climates with strong seasonal temperature and precipitation fluctuations (e.g. deserts and savannas). Nondormancy is associated with stable, warm and wetter climates (e.g. tropical rain forest). Pyroclimate had no significant effect on the distribution of seed dormancy.</li><li>The environmental drivers considered in this study had a comparatively low predictive power, suggesting that macroclimate is just one of several global drivers of seed dormancy.</li></ul>

opencc-by-4.0May 2022View details →

Statistically Determined Global Fire Regimes (GFRs) Empirically Characterized Using Historical MODIS Hotspots

Statistically Determined Global Fire Regimes (GFRs) Empirically Characterized Using Historical MODIS Hotspots Fire regimes are areas having similar fire characteristics, and show the spatial pattern, frequency and intensity of fires that prevail in that area over long periods of time. Fire regimes are created and maintained by multivariate interactions between climate, vegetation/fuels, and ignitions. Like ecoregions, fire regimes indicate the extent and overlap of particular vegetative/fuel communities and climatic conditions, and are important for understanding, monitoring, predicting and managing fire. More than 83M MODIS “hotspot” thermal detections from 2002-2019 were grouped into 10km cells, and 21 derived variables describing fire characteristics of fire intensity, return frequency, and seasonality within each cell were developed and subjected to unsupervised Multivariate Geographic Clustering to produce world maps of Global Fire Regimes (GFRs), each having similar fire intensity and timing characteristics. Methodology behind these datasets are described in manuscript currently in review. W. W. Hargrove, Jitendra Kumar, Steven P. Norman, Forrest M. Hoffman (2022), "Empirical Characterization of Global Fire Regimes Show Shared Fire Relationships" 2022 (in review) This data collection includes: 1. Multivariate Geographic Clustering Global Fire Regimes at 3000, 1000, 500, 100, 50, 20, 10 levels of divisions in form of geospatial raster in IMG formats, and associated color tables. 2. Characteristics of GFRs 3. Location groups 4. Geospatial maps of global fire frequency modes, global seasonality strength, and 12 types of global fires. 5. PNG maps for all data products  6. Description and script for global date transform algorithm.

opencc-by-4.0Jun 2024View details →

Collapse and recovery of livestock systems shape fire regimes on the Eurasian steppe: a review of ecosystem and biodiversity implications

This file contains bibliographic data from the literature research; livestock and fire data as well as Google Earth Engine and R-scripts to reproduce all analyses and figures.

opencc-zeroJan 2023View details →

Data and code from: Shifting social-ecological fire regimes explain increasing structure loss from Western wildfires

Higuera, P.E., M.C. Cook, J.K. Balch, E.N. Stavros, A.L. Mahood, and L.A. St. Denis. 2023. Shifting social-ecological fire regimes explain increasing structure loss from Western wildfires. PNAS Nexus 2: In Press. Structure loss is an acute, costly impact of the wildfire crisis in the western United States ("West"), motivating the need to understand recent trends and causes. We document a 246% rise in West-wide structure loss from wildfires between 1999–2009 and 2010–2020, driven strongly by events in 2017, 2018, and 2020. Increased structure loss was not due to increased area burned alone. Wildfires became significantly more destructive, with a 160% higher structure loss rate (loss/kha burned) over the past decade. Structure loss was driven primarily by wildfires from unplanned human-related ignitions (e.g. backyard burning, power lines, etc.), which accounted for 76% of all structure loss and resulted in 10 times more structures destroyed per unit area burned compared to lightning-ignited fires. Annual structure loss was well explained by area burned from human-related ignitions, while decadal structure loss was explained by state-level structure abundance in flammable vegetation. Both predictors increased over recent decades and likely interacted with increased fuel aridity to drive structure-loss trends. While states are diverse in patterns and trends, nearly all experienced more burning from human-related ignitions and/or higher structure loss rates, particularly California, Washington, and Oregon. Our findings highlight how fire regimes – characteristics of fire over space and time – are fundamentally social-ecological phenomena. By resolving the diversity of Western fire regimes, our work informs regionally appropriate mitigation and adaptation strategies. With millions of structures with high fire risk, reducing human-related ignitions and rethinking how we build are critical for preventing future wildfire disasters.

opencc-by-4.0Dec 2022View details →

Data from Widespread exposure to altered fire regimes under 2°C warming is projected to transform conifer forests of the Western United States

This archive includes a minimal dataset needed to reproduce the analysis as well as a table (CSV) and spatial polygons (ESRI shapefile) of the resulting output from the publication: Hoecker, T.J., S. A. Parks, M. Krosby & S. Z. Dobrowski. 2023. Widespread exposure to altered fire regimes under 2°C warming is projected to transform conifer forests of the Western United States. Communications Earth and Environment. Publication abstract: Changes in wildfire frequency and severity are altering conifer forests and pose threats to biodiversity and natural climate solutions. Where and when feedbacks between vegetation and fire could mediate forest transformation are unresolved. Here, for the western U.S., we used climate analogs to measure exposure to fire-regime change; quantified the direction and spatial distribution of changes in burn severity; and intersected exposure with fire-resistance trait data. We measured exposure as multivariate dissimilarities between contemporary distributions of fire frequency, burn severity, and vegetation productivity and distributions supported by a 2 °C-warmer climate. We project exposure to fire-regime change across 65% of western US conifer forests and mean burn severity to ultimately decline across 63% because of feedbacks with forest productivity and fire frequency. We find that forests occupying disparate portions of climate space are vulnerable to projected fire-regime changes. Forests may adapt to future disturbance regimes, but trajectories remain uncertain.

opencc-zeroSep 2023View details →

Data archive for: Fire-regime variability and ecosystem resilience over four millennia in a Rocky Mountain subalpine watershed

Wildfires strongly influence forest ecosystem processes, including carbon and nutrient cycling and vegetation dynamics. As fire activity increases under changing climate conditions, the ecological and biogeochemical resilience of many forest ecosystems remains unknown. To investigate the resilience of forest ecosystems to changing climate and wildfire activity over decades to millennia, we developed a 4800-yr high-resolution lake-sediment record from Silver Lake, Montana, USA (47.360° N, 115.566° W). Charcoal particles, pollen grains, element concentrations, and stable isotopes of C and N serve as proxies of past changes in fire, vegetation, and ecosystem processes such as nitrogen cycling and soil erosion, within a small subalpine forest watershed. A published lake-level history from Silver Lake provides a local record of paleohydrology. A trend toward increased effective moisture over the late Holocene coincided with a distinct shift in the pollen assemblage c. 1900 yr BP, resulting from increased subalpine conifer abundance. Fire activity, inferred from peaks in macroscopic charcoal, decreased significantly after 1900 yr BP, from one fire event every 126 yr (83–184 yr, 95% CI) from 4800–1900 yr BP, to one event every 223 yr (175–280 yr) from 1900 yr BP to present. Across the record, individual fire events were followed by two distinct decadal-scale biogeochemical responses, reflecting differences in ecosystem impacts of fires on watershed processes. These distinct biogeochemical responses were interpreted as reflecting fire severity, highlighting (i) erosion, likely from large or high-severity fires, and (ii) nutrient transfers and enhanced within-lake productivity, likely from lower-severity or patchier fires. Biogeochemical and vegetation proxies returned to pre-fire values within decades regardless of the nature of fire effects. Paleo records of fire and ecosystem responses provide a novel view revealing past variability in fire effects, analogous to spatial variability in fire severity observed within contemporary wildfires. Overall, the paleo record highlights ecosystem resilience to fire across long-term variability in climate and fire activity. Higher fire frequencies in past millennia relative to the 20th and 21st centuries suggest that northern Rocky Mountain subalpine ecosystems could remain resilient to future increases in fire activity, provided continued ecosystem recovery within decades.

publicJan 2023View details →

Data and code from: Shifting social-ecological fire regimes explain increasing structure loss from Western wildfires

Open the record for dataset details and reuse information.

publicSep 2023View details →

Data archive for: Fire-regime variability and ecosystem resilience over four millennia in a Rocky Mountain subalpine watershed

Open the record for dataset details and reuse information.

opencc-zeroFeb 2024View details →

Data from: Mediterranean bioclimate zones of the world for the understanding of fire regimes

Aim: To quantify the role of soil fertility in the spatial variability of fire activity and to identify the mechanisms that drive this variability. Location: The five Mediterranean-type climate regions of the world. Time period: 2002 – present. Major taxa studied: Terrestrial plants. Methods: We compiled remotely sensed data on fire activity, climate, net primary productivity, and chemical soil properties for bioclimatically homogeneous zones within the five Mediterranean-type climate regions of the world. Putative direct and indirect effects of the environmental variables on fire activity were evaluated through structural equation modelling. Results: Fire activity increased with net primary productivity, as expected for ecosystems with fuel-limited fire regimes. Soil acidity and the concentration of exchangeable aluminium also increased fire activity, supporting the idea that low fertility promotes plant characteristics that favour fire initiation and spread. Main conclusions: Our research supports a positive relationship between wildfires and low soil fertility in Mediterranean-type climate regions across the globe. Therefore, soil fertility should be incorporated into models predicting future fires in a warming world.

zenodo36/100

Drivers of extreme wildfire years in the 1965–2019 fire regime of the Tłı̨chǫ First Nation territory, Canada

Datasets, metadata and Rscript used to describe 1965-2019 wildfire regime and extreme wildfire years in central NWT.

opencc-by-4.0Feb 2022View details →

zenodo36/100

Fire regime parameters and potential biophysical fire regime drivers - NUTS2 Centro, Portugal

The dataset, presented as an SPSS data file, includes three components. All were calculated for the civil parishes comprised in the NUTS2 Centro territorial unit in Central Portugal, identified by name in the column Parish_name. These components are: 1) three fire regime descriptors (expressed in original units and as z-scores) 2) twelve potential biophysical fire regime drivers (expressed in original units and as z-scores). 3) the cluster associated to each parish in both 3-cluster and 4-cluster solutions, obtained by running cluster analyses using the three fire regime descriptors as input variables. All fire regime descriptors and potential fire regime drivers are described in: Bergonse, R., Oliveira, S., Zêzere, J. L., Moreira, F., Ribeiro, P. F., Leal, M., & Lima e Santos, J. M. (2022). Biophysical controls over fire regime properties in Central Portugal. Science of The Total Environment, 810, 152314. <a href="https://doi.org/10.1016/j.scitotenv.2021.152314">https://doi.org/10.1016/j.scitotenv.2021.152314</a>. They are also identified in the ReadMe file included in the Dataset.

opencc-by-4.0May 2022View details →

opencc-zeroDec 2021View details →

Data from: Pyrogeography across the western Palearctic: A diversity of fire regimes

We characterised fire regimes and estimated fire regime parameters (area burnt, size, intensity, season, patchiness, pyrodiversity) at broad spatial scales using remotely sensed individual-fire data. Specifically, we focused on the western part of the Palearctic realm, i.e., Europe, North Africa, and the Near East. We first divided the study area into eight large ecoregions based on their environment and vegetation (ecoregions): Mediterranean, Arid, Atlantic, Mountains, Boreal, Steppes, Continental, and Tundra. Then we intersected each ecoregion with individual-fire data obtained from remote sensing hotspots to estimate fire regime parameters for each environment. This allowed us to compute annual area burnt, fire size, fire intensity, fire season, fire patchiness, fire recurrence, and pyrodiversity for each ecoregion. We then related those fire parameters with the ecoregions' climate and analysed the temporal trends in fire size. The results suggest that fire regime parameters vary across different environments (ecoregions). The Mediterranean had the largest, most intense, and most recurrent fires, but the Steppes had the largest burnt area. Arid ecosystems had the most extended fire season, Tundra had the patchiest fires, and Boreal forests had the earliest fires of the year. The spatial variability in fire regimes was largely explained by the variability of climate and vegetation, with a tendency for greater fire activity in the warmer ecoregions. There was also a temporal tendency for fires to become larger during the last two decades, especially in Arid and Continental environments. In conclusion, fire regime characteristics of each ecoregion are unique, with a tendency for greater fire activity in warmer environments, and for increasingly large fires in recent decades.

zenodo36/100

Assessment of the Effectiveness of Coarse Resolution Fire Products in Monitoring Long-term Changes in Fire Regime within Protected Areas in South Africa

The dataset includes fire histrory (shapefiles with data perimeters for 2003-2020) within 3 protected areas in South Africa, Blyde, Manyeleti, and Songimvelo.

opencc-by-4.0Jul 2024View details →

opencc-zeroDec 2017View details →

Data from: Influences of fire–vegetation feedbacks and post-fire recovery rates on forest landscape vulnerability to altered fire regimes

1. In the context of on-going climatic warming, forest landscapes face increasing risk of conversion to non-forest vegetation through alteration of their fire regimes and their post-fire recovery dynamics. However, this pressure could be amplified or dampened, depending on how fire-driven changes to vegetation feed back to alter the extent or behavior of subsequent fires. 2. Here we develop a mathematical model to formalize understanding of how fire–vegetation feedbacks and the time to forest recovery following high-severity (i.e., stand-replacing) fire affect the extent and stability of forest cover across landscapes facing altered fire regimes. We evaluate responses to increasing burn rates while varying the direction (negative vs. positive) of fire–vegetation feedbacks under a continuum of values for feedback strength and post-fire recovery time to determine how interactions among these variables produce thresholds and tipping points in landscape responses to changing fire regimes. 3. Where the early-seral vegetation is less fire-prone than older forests, negative feedbacks limited the reductions in forest cover in response to increased fire frequency or slower forest recovery. By contrast, positive feedbacks (more flammable early-seral vegetation) produced a tipping point beyond which increased burn rates or slower forest recovery drove extensive forest loss. 4. With negative feedbacks, the rates of forest loss and expansion in response to variation in fire frequency were similar. However, where feedbacks are positive, the conversion from predominantly forested to non-forested conditions in response to increased fire frequency was faster than the re-expansion of forest cover following a return to the initial burn rate. Strengthening the positive feedbacks increased this asymmetry. 5. Synthesis. Our analyses elucidate how fire–vegetation feedbacks and post-fire recovery rates interact to affect the trajectories and rates of landscape response to altered fire regimes. We illustrate the vulnerability of ecosystems with positive fire–vegetation feedbacks to climate change-driven increases in fire activity, especially where post-fire recovery is slow. Although negative feedbacks initially provide resistance to forest loss with increasing burn rates, this resistance is eventually overwhelmed with sufficient increases to burn rates relative to recovery times.

opencc-zeroOct 2022View details →

Resistance of termite mounds to variation in long-term fire regimes across semi-arid African savannas

1. Fire regimes are expected to change with climate change, resulting in a crucial need to understand the specific ways in which variable fire regimes impact important contributors to ecosystem functioning, such as mound-building termites. Termite mounds and fire are both important agents of savanna ecosystem heterogeneity and functioning, but there is little understanding of how they interact across savanna types. 2. We used very high-resolution LiDAR remote sensing to measure the size, density, and distribution of termite mounds across approximately 1,300 ha of experimental burn plots in four South African savanna landscapes representing a wide range of fire treatments differing in seasonality and frequency of burning. 3. In nutrient-poor granitic savannas, fire had no impact on termite mound size, densities, and spatial distributions. In nutrient-rich basaltic savannas with high mammalian herbivore abundance and intermediate rainfall, very frequent fires caused a decrease in termite mound size, whereas in arid nutrient-rich basaltic savannas, fires that occurred at intermediate frequencies and in transitional seasons (i.e., late dry season and late wet season) decreased the degree of spatial overdispersal exhibited by mounds. 4. Overall, our results suggest that termite mounds are resistant to variation in fire seasonality and frequency, likely indicating that ecosystem services provided by mound-building termites will be unaffected by changing fire regimes. However, consideration of changes to termite mound size and distribution could be necessary for land managers in specific savanna types, such as nutrient-rich soils with high mammalian herbivore abundance.