Fire Intervals Research Articles

Expert-Informed Habitat Suitability Analysis for At-Risk Species Assessment and Conservation Planning

Abstract The U.S. Fish and Wildlife Service (USFWS) is responsible for reviewing the biological status of hundreds of species to determine federal status designations under the Endangered Species Act. The longleaf pine Pinus palustris ecological system supports many priority at-risk species designated for review, including five species of herpetofauna: gopher tortoise Gopherus polyphemus, southern hognose snake Heterodon simus, Florida pine snake Pituophis melanoleucus mugitus, gopher frog Lithobates (Rana) capito, and striped newt Notophthalmus perstriatus. To inform status decisions and conservation planning, we developed habitat suitability models to 1) identify habitat features that best predict species presence and 2) estimate the amount and distribution of suitable habitat across each species' range under current conditions. We incorporated expert judgment from federal, state, and other partners to capture variation in ecological settings across species' ranges, prioritize predictor variables to test in models, mitigate data limitations by informing the selection of pseudoabsence points, qualitatively evaluate model estimates, and improve the likelihood that experts will trust and use model predictions for conservation. Soil characteristics, land cover, and fire interval strongly influenced habitat suitability for all species. Suitable habitat was distributed on known species strongholds, as well as private lands without known species records. Between 4.7% (gopher frog) and 14.6% (gopher tortoise) of the area in a species' range was classified as suitable habitat, and between 28.1% (southern hognose snake) and 47.5% (gopher frog) of suitable habitat was located in patches larger than 1 km2 (100 ha) on publicly owned lands. By overlaying predictions for each species, we identified areas of suitable habitat for multiple species on protected and unprotected lands. These results have direct applications to management and conservation planning: partners can tailor site-level management based on attributes associated with high habitat suitability for species of concern; allocate survey effort in areas with suitable habitat but no known species records; and identify priority areas for management, land acquisitions, or other strategies based on the distribution of species records, suitable habitat, and land protection status. These results can aid regional partners in implementing effective conservation strategies and inform status designation decisions of the USFWS.

Analysis of fire frequency on the Talladega National Forest, USA, 1998-2018

Fire is an essential ecological process and management tool for many forested landscapes, particularly the pine (Pinus spp.) forests of the southern USA. Within the Talladega National Forest in Alabama, where restoration and maintenance of pine ecosystems is a priority, fire frequency (both wild and prescribed) was assessed using a geographical process applied to a fire history database. Two methods for assessing fire frequency were employed: (1) a simple method that utilised the entire range of years acknowledged in the database and (2) a conservative method that was applied only the date of the first and last fires recorded at each location. Analyses were further separated by (a) method of mean fire return interval calculation (weighted by area or Weibull) and (b) fire season interval with analyses conducted on growing season and dormant season fires. Analyses of fire frequency for national forest planning purposes may help determine whether a prescribed fire program mimics ecological and historical fire frequencies and meets intended objectives. The estimated fire return interval was between ~5 and 6.5 years using common, straightforward (simple) methods. About one-third of the forest receives no fire management and about half of the balance has sufficiently managed fuels.

A Time Petri Net With Relaxed Mixed Semantics for Schedulability Analysis of Flexible Manufacturing Systems

Several semantics models are adopted by time Petri nets for different applications. Yet they have some limitations on schedulability analysis of flexible manufacturing systems. The scheduling scope of a strong semantics model is greatly limited because of the impact of strong timing requirements, perhaps keeping some optimal schedules out of the consideration. A weak semantics model cannot guarantee the scheduling timeliness as there lacks strong timing enforcement. A mixed semantics model cannot ensure that independent transitions with overlapping firing interval fire in an interleaving way, thus affecting the search for the optimal schedules. In this paper, we present a relaxed mixed semantics model for time Petri nets to address these problems by redefining the firability rules of transitions. In our model, the firability of a transition is determined by maximal concurrent sets containing the transition. This treatment not only extends the scheduling scope of TPN model greatly while avoiding the generation of invalid schedules, but also solves the problem of concurrent scheduling of independent transitions. A state class method is then proposed to support the verification and analysis of temporal properties. Finally, we apply the proposed model to schedulability analysis of a job shop scheduling problem, and compare the features of four semantics models.

ОПРЕДЕЛЕНИЕ ОПТИМАЛЬНОГО ТЕМПЕРАТУРНОГО ИНТЕРВАЛА ДЛЯ ПРЕДВАРИТЕЛЬНОГО ОБЖИГА КАОЛИНА

The effect of pre-firing of kaolin concentrates on the yield of aluminum hydroxide during nitric acid leaching by cavitation method is studied. The firing interval of 700-750 ° C is optimal for maximum opening of kaolin concentrate.

A Reduced Computation of State Space to Enforce GMECs and Deadlock-Freeness on TPN Systems

Abstract This paper analyzes the enforcement of Generalized Mutual Exclusion Constraints (GMECs) and deadlock-freeness on a Time Petri net (TPN) system with uncontrollable transitions, motivated by the fact that the existing methods enforcing GMECs may degrade the performance of a closed-loop system and lead to deadlock states. By exploiting timing information and mathematical programming, a control function is designed to restrict the firing intervals of transitions such that a TPN system can avoid entering forbidden states. The key idea behind the proposed approach is the online computation of a graph, called Reduced Modified State Class Graph, that is derived from another graph recently presented in the literature.

Dwarf Blackgum (Nyssa sylvatica) Contains Datable Fire Scars that Complement an Existing Fire History

Blackgum (Nyssa sylvatica) is a “consummate subordinate” hardwood tree species consigned to the mid-canopy of many eastern North American forests. Despite its wide distribution and ecological amplitude, blackgum is an underutilized tree species in fire history reconstructions within its range. In this study, I analyzed cross-section samples collected from 19 fire-scarred blackgum trees at a dry, nutrient-poor ridgetop study area in northeastern Pennsylvania. All but two of these samples were successfully crossdated, each containing between one and six fire scars. Fires recorded by blackgum occurred frequently, with site-level mean fire intervals between approximately three and five years. There was an increase in blackgum growth within two years following fire events, but this increase was not statistically significant and it was dependent on local fire regime characteristics. In addition, the blackgum fire-scar data increased the temporal and spatial resolution of an existing local fire history. These results provide evidence for the potential use of blackgum in fire history reconstructions, but applications may be limited by tree age, complacent growth that prevents crossdating, and the degree of rot resistance after scarring.

Time since fire and prior fire interval shape woody debris dynamics in obligate‐seeder woodlands

AbstractWoody debris plays an important role in many ecosystem functions, including nutrient and carbon cycling, providing substrates for plant recruitment and habitat for fauna. Fires can affect woody debris stocks, through generating new pieces by killing or severing plant parts and consuming pre‐existing woody debris. We develop a model of woody debris dynamics with variation in time since fire and prior fire interval applicable to obligate‐seeder forests and woodlands, considering down woody debris and standing dead trees as discrete components. We then test predictions of change in woody debris derived from this model in Eucalyptus salubris woodlands in South‐Western Australia, using a multi‐century chronosequence with recent fires varying between having short (<50 yr since the previous fire) or long (>50 yr, but often much longer) prior intervals. As per our woody debris dynamics model, most attributes measured were affected by time since fire, prior fire interval, or their interaction. Woody debris biomass was greatest shortly after fire, reflecting high quantities of standing dead trees resulting from stand‐replacement disturbance. Standing dead tree density and biomass then declined with increasing time since fire, but individual dead tree size was high beyond 200 yr since fire. Down woody debris biomass remained relatively stable with time since fire, but piece size increased. Dimensions of woody debris were strongly influenced by prior fire interval, with long prior intervals resulting in pieces at least twice the size than those occurring after short prior intervals. Fire management to maximize the availability of large woody debris pieces for fauna should aim to minimize short fire intervals, while from a carbon management perspective, all fires in obligate‐seeder forests and woodlands set in train large and prolonged emissions of carbon.

Better lucky than good: How savanna trees escape the fire trap in a variable world.

Fire controls tree cover in many savannas by suppressing saplings through repeated topkill and resprouting, causing a demographic bottleneck. Tree cover can increase dramatically if even a small fraction of saplings escape this fire trap, so modeling and management of savanna vegetation should account for occasional individuals that escape the fire trap because they are "better" (i.e., they grow faster than average) or because they are "lucky" (they experience an occasional longer-than-average interval without fire or a below-average fire severity). We quantified variation in growth rates and topkill probability in Quercus laevis (turkey oak) in longleaf pine savanna to estimate the percentage of stems expected to escape the fire trap due to variability in (1) growth rate, (2) fire severity, and (3) fire interval. For trees growing at the mean rate and exposed to the mean fire severity and the mean fire interval, no saplings are expected to become adults under typical fire frequencies. Introducing variability in any of these factors, however, allows some individuals to escape the fire trap. A variable fire interval had the greatest influence, allowing 8% of stems to become adults within a century. In contrast, introducing variation in fire severity and growth rate should allow 2.8% and 0.3% of stems to become adults, respectively. Thus, most trees that escape the fire trap do so because of luck. By chance, they experience long fire-free intervals and/or a low-severity fire when they are not yet large enough to resist an average fire. Fewer stems escape the fire trap by being unusually fast-growing individuals. It is important to quantify these sources of variation and their consequences to improve understanding, prediction, and management of vegetation dynamics of fire-maintained savannas. Here we also present a new approach to quantifying variation in fire severity utilizing a latent-variable model of logistic regression.

Prescribed burning in a mediterranean-climate region mitigates the disturbance by bushfire to a critical food resource for an endangered bird, the Carnaby\u2019s cockatoo

BackgroundPrescribed burning is used to reduce fire hazard in highly flammable vegetation types, including Banksia L.f. woodland that occurs on the Swan Coastal Plain (SCP), Western Australia, Australia. The 2016 census recorded well over 1.9 million people living on the SCP, which also encompasses Perth, the fourth largest city in Australia. Banksia woodland is prone to frequent ignitions that can cause extensive bushfires that consume canopy-stored banksia seeds, a critical food resource for an endangered bird, the Carnaby’s cockatoo (Calyptorynchus latirostris, Carnaby 1948). The time needed for banksias to reach maturity and maximum seed production is several years longer than the typical interval between prescribed burns. We compared prescribed burns to bushfires and unburned sites at three locations in banksia woodland to determine whether low-intensity prescribed burns affect the number of adult banksias and their seed production. Study sites were matched to the same vegetation complex, fire regime, and time-since-fire to isolate fire intensity as a variable.ResultsHeadfire rates of spread and differenced normalized burn ratios indicated that prescribed burning was generally of a much lower intensity than bushfire. The percentage survival of adult banksias and their production of cones and follicles (seeds) did not decrease during the first three years following a prescribed burn. However, survival and seed production were significantly diminished followed high-intensity bushfire. Thus, carrying capacity for Carnaby’s cockatoo was unchanged by prescribed burning but decreased markedly following bushfire in banksia woodland.ConclusionsThese results suggest that prescribed burning is markedly different from bushfire when considering appropriate fire intervals to conserve canopy habitats in fire-resilient vegetation communities. Therefore, low-intensity prescribed burning represents a viable management tool to reduce the frequency and extent of bushfire impacts on banksia woodland and Carnaby’s cockatoo.

Effects of fire rotation interval and overstory type on ambient soil temperatures in ponderosa pine forests in Arizona

Ambient soil temperatures were measured every four weeks from May 1986 to November 1986 at three depths under the organic forest floor in ponderosa pine (Pinus ponderosa Lawson & C. Lawson) forests in three stand types subjected to periodic prescribed burning. Temperatures at the organic layer – soil surface interface in sawtimber stands were higher and more variable than in pole and saplings stands. Temperature variability reached a maximum in the summer and decreased into the fall and early winter. Soil temperature variability decreased as depth below the surface increased. Three years after the low-intensity prescribed burns, soil temperatures in the burned stands were not significantly different from the those in the unburned controls, suggesting that any effect, though none was detected, of the low-intensity prescribed burns on soil temperature and belowground processes affected by temperature is short-lived in these stands.

Framework for monitoring shrubland community integrity in California Mediterranean type ecosystems: Information for policy makers and land managers

AbstractShrublands in Mediterranean‐type ecosystems worldwide support important ecosystem services including high levels of biodiversity and are threatened by multiple factors in heavily used landscapes. Use, conservation, and management of these landscapes involve diverse stakeholders, making decision processes complex. To be effective, management and land use decisions should be informed by current information on ecosystem quality and resilience. However, obtaining this information is often a challenge due to the extent of landscapes involved. Here we present a conceptual integrity monitoring framework based on simple easily observable ecosystem components readily understood by nonspecialists. Community integrity is defined by plant functional group based on relative proportion of shrubs and nonnative annual grasses. The ability to use these straightforward metrics results from four factors: relatively good alignment of characteristic bird, mammal, and insect communities with shrub cover, positive feedback between annual grasses and short fire intervals, the inhibitory effect of annual grasses on shrub seedling establishment, and similar functional group response to different disturbances. Two additional metrics, indicator species and shrub species diversity, capture subtle yet persistent signatures of disturbance on integrity not reflected in functional group composition. The framework is designed to: categorize habitats into ecosystem integrity classes, forecast likely integrity class changes caused by threats and environmental conditions, and provide a simple reporting mechanism that can be overlain with data on conservation status and vulnerabilities. The proposed framework includes a pilot phase to validate empirical relationships, thresholds, and sampling efficiency. The accessibility of these metrics to nonspecialists is anticipated to enhance communication among stakeholders and thus facilitate problem solving. Leveraging monitoring and mapping programs driven by other needs (e.g., species conservation and fire management) affords meaningful opportunities to offset program costs.

Historical fire in the Appalachian Plateau of Ohio and Kentucky, USA, from remnant yellow pines

BackgroundKnowledge of historical fire regimes informs the restoration of woodland communities. In the Appalachian Plateau of Ohio and Kentucky, USA, little is known about the long-term history of fire in oak–pine communities, which are declining in the region. To address this knowledge gap, two sites with remnant fire-scarred yellow pines, Hatton Ridge in Kentucky and McAtee Run in Ohio, were studied to document aspects of the historical fire regime. Cross-sections from fire-scarred yellow pines were collected. Fire chronologies were constructed and fire intervals were calculated using standard dendrochronological methods.ResultsFires, the great majority of which occurred in the dormant season, were frequent at both sites from circa 1750 at Hatton and 1800 at McAtee, until the suppression period (1930 to present); only one fire was recorded after 1930. Mean fire intervals (MFI) for the entire period were nearly identical, 4.7 and 4.4 years at Hatton and McAtee, respectively. At both sites, MFIs were lowest in the industrial period (1850 to 1930). At Hatton, the MFI was 6.6 years before 1850 and 3.5 years from 1850 to 1930, while at McAtee, the MFI was 8.4 years before 1850 and 2.7 years from 1850 to 1930. At both sites, the occurrence of fire was not more frequent than expected in years associated with a drought. At McAtee, the majority of pine establishment occurred in pulses during two periods, 1770 to 1781 and 1853 to 1867, suggesting stand-scale canopy disturbances; the second pulse was associated with frequent burning. In contrast, large pulses of pine establishment were not found at Hatton.ConclusionsYellow pines were a component of these communities, which experienced frequent fire for at least 130 to 160 years. After more than 70 years with little or no fire, yellow pines are now a minor component of the overstory and pine regeneration is essentially absent. Although intensive management with partial harvesting and frequent fire would be required to restore oak–pine woodlands on appropriate sites, it would serve to sustain these increasingly uncommon communities.

Fire in central Piedmont as recorded by fire scars at Pilot Mountain State Park, NC

ABSTRACTFire has been well studied in the Appalachians but has not been well characterized within Piedmont xeric forests. Herein we describe a dendrochronological study at Pilot Mountain State Park, NC addressing the following: How frequently did this forest experience fire? Is fire occurrence correlated with drought conditions? How did fire activity change with the onset of suppression? How does the fire regime compare with xeric Appalachian forests and prior models of Piedmont fire frequency? Seventy samples documented 34 fires between 1849–2014. The first fire occurred in 1891 and the first two-scar fire occurred in 1904. The composite Mean Fire Interval and Weinbull Median Interval pre-suppression (pre-1930; 2.36 and 2.25 years, respectively) were almost half that of the suppression period (post-1930; 4.56 and 4.09 years, respectively). With suppression, the Decadal Fire Index and mean number of scars per fire declined significantly (p ≤ 0.05 and ≤ 0.001). The Pre-suppression Filtered Composite MFI (4.2 years) was lower than any reported for the Appalachians and agrees with previous model predictions. Fire activity was strongly correlated with drought 2 years prior, before suppression but not afterward. As documented here, fire scars on xeric forest pines may contain important records of the Piedmont’s fire history.

Wandering spiders recover more slowly than web-building spiders after fire.

Fire is a natural feature of many ecosystems, with some vegetation types highly adapted to fire. However, very little is known about the effect of fire on spiders, especially as fires have become more frequent owing to human activity. We determine whether different spider functional guilds (web builders vs. wanderers) respond differently to fires in the sclerophyllous fynbos. We determine also the effect of rockiness as refuge for these guilds and whether it influences their post-fire recovery. There were three site categories of time-since-last fire: 3 months, 1 year, and 7 years. We found that fire caused a decline in spider richness and abundance, with the 3-month category supporting the lowest. In sites that were burned within 1year, abundance of wanderers was as high as in sites that had 7years to recover, whereas species richness and abundance of web builders in sites that were burned 1year ago were as low as in recently burned sites. However, assemblages of wanderers differed among categories, while no differences were observed for web builders, highlighting that wanderers took longer time to recover than web builders. Species richness and abundance of both guilds were not affected by different levels ofrockiness. However, rockiness is important in shaping assemblages of wanderers. The results emphasize that the assemblages of greatest conservation concern with increased fire frequencies are wanderers and are candidate surrogates for monitoring post-fire recovery. These results highlight the need to allow fynbos vegetation to recover fully between fire intervals and draws attention to the dangers of frequent unplanned fires.

Multi-scale synthesis of historical fire regimes along the south-central US prairie\u2013forest border

BackgroundAlong the prairie–forest border in the south-central USA exists one of the most extensive areas of uncut forest in the nation (>323 750 hectares), providing unique potential for developing multi-century records of environmental changes through dendrochronological analyses. Twentieth century changes in vegetation, increased prescribed fire management, and recent years of elevated wildfire activity have increased interest in understanding the region’s long-term fire regime characteristics. To address this need, we analyzed and compared fire intervals, seasonality, severity, and extent based on fire-scar history datasets from three new and ten existing study sites.ResultsAt the study sites, mean fire intervals ranged from 3 to 10 years prior to Euro-American settlement and generally became more frequent after. The majority of fires occurred in the dormant season and resulted in low percentages of trees scarred. Coinciding with Euro-American settlement (EAS), fire frequencies appear to have varied by geography. At the regional scale, fire regimes have trended towards decreased fire severity and slightly decreased fire intervals over the past 300 years. Further, fires appear to have increased in extent from circa 1770 to the mid to late 1800s, after which it began to decline, circa 1920.ConclusionsAlthough frequent, descriptions of fire regimes since the eighteenth century should be characterized as time-dependent and spatially variable, likely depending on local socio-ecological influences. Similar influences may explain fire frequency increases following EAS, while fire severity trended lower.

Fire as a key driver of Earth's biodiversity.

Many terrestrial ecosystems are fire prone, such that their composition and structure are largely due to their fire regime. Regions subject to regular fire have exceptionally high levels of species richness and endemism, and fire has been proposed as a major driver of their diversity, within the context of climate, resource availability and environmental heterogeneity. However, current fire-management practices rarely take into account the ecological and evolutionary roles of fire in maintaining biodiversity. Here, we focus on the mechanisms that enable fire to act as a major ecological and evolutionary force that promotes and maintains biodiversity over numerous spatiotemporal scales. From an ecological perspective, the vegetation, topography and local weather conditions during a fire generate a landscape with spatial and temporal variation in fire-related patches (pyrodiversity), and these produce the biotic and environmental heterogeneity that drives biodiversity across local and regional scales. There have been few empirical tests of the proposition that 'pyrodiversity begets biodiversity' but we show that biodiversity should peak at moderately high levels of pyrodiversity. Overall species richness is greatest immediately after fire and declines monotonically over time, with postfire successional pathways dictated by animal habitat preferences and varying lifespans among resident plants. Theory and data support the 'intermediate disturbance hypothesis' when mean patch species diversity is correlated with mean fire intervals. Postfire persistence, recruitment and immigration allow species with different life histories to coexist. From an evolutionary perspective, fire drives population turnover and diversification by promoting a wide range of adaptive responses to particular fire regimes. Among 39 comparisons, the number of species in 26 fire-prone lineages is much higher than that in their non-fire-prone sister lineages. Fire and its byproducts may have direct mutagenic effects, producing novel genotypes that can lead to trait innovation and even speciation. A paradigm shift aimed at restoring biodiversity-maintaining fire regimes across broad landscapes is required among the fire research and management communities. This will require ecologists and other professionals to spread the burgeoning fire-science knowledge beyond scientific publications to the broader public, politicians and media.

The negative impacts of fire on the resurrection ecology of invertebrates from temporary wetlands in Cape Flats Sand Fynbos in the Western Cape, South Africa

AbstractFire is an important environmental disturbance in Mediterranean‐climate regions; however, its intensity and frequency are predicted to increase under climate change scenarios with unknown implications for ecosystems in these regions. Temporary wetlands, with their periodic wet and dry phases, are considered one of the most productive systems in the world and their invertebrate communities form a crucial diet component for higher trophic levels. The effect of fire on the hatching success of invertebrate propagules from temporary wetlands in the Cape Flats Sand Fynbos (Cape Town, South Africa) was investigated. Homogenised soil samples from these wetlands were either experimentally subjected to vegetation fires (treatment samples) or were left as is (control samples). The results revealed that fire had a significant negative impact on invertebrate hatching success, as revealed by analyses of the different diversity measures (e.g. taxon richness, Shannon diversity and Pielou's evenness) and community composition. Proper management of fire, especially in the Mediterranean‐climate regions, which replicates the natural fire intervals typical of the area (10–15 years) and avoids unregulated or accidental fires, is essential to ensuring future protection of these critical biodiversity hotspots created by the temporary wetlands.

Extent and drivers of vegetation type conversion in Southern California chaparral

AbstractThe native chaparral shrublands of Southern California support exceptional biodiversity and provide critical ecological services, but increased fire frequency threatens to extirpate much of the chaparral due to long regeneration times needed between fires for many species. When short fire intervals inhibit shrub recovery, this favors invasion of exotic herbaceous species, and vegetation type conversion from woody shrubs to grassland is therefore a serious ecological concern in this biodiversity hotspot. Despite a history of field studies documenting the detrimental effect of short‐interval fire, the extent of vegetation type conversion and the conditions under which it occurs have not been documented at a landscape scale. Our objective was thus to provide an unbiased assessment of how and how much vegetation type conversion is occurring in Southern California chaparral. We used a chronosequence of aerial photographs to quantify percentage woody and herbaceous cover change from 1953 to 2016 across randomly sampled plots in San Diego County, then related conversion and decline to a range of explanatory variables including fire, proximity to human disturbance, and biophysical landscape characteristics. Within the 63‐yr study period, there was substantial net woody cover loss, and in the plots that were initially more than 75% woody cover in 1953, 59% experienced a decline, with a mean woody cover loss of 22.5%. Of these, 28% heavily type‐converted to the point that herbaceous vegetation covered more than 50% of the plot. The top drivers for woody conversion and decline included a fire interval shorter than 15 yr and total number of fires, actual evapotranspiration, and elevation. Although human land use variables were not strong independent contributors to either chaparral conversion or decline, 26% of the initial vegetated plots were directly converted to development or other human disturbance types. The combination of direct habitat loss and unintentional vegetation type conversion represents a substantial ecological impact in Southern California that can have far‐reaching impacts via loss of ecological services and by increasing the flammability of the landscape in general. Efforts to reduce fire frequency will be key to preventing further losses.

A global synthesis of fire effects on pollinators

AbstractAimUnderstanding fire effects on pollinators is critical in the context of fire regime changes and the global pollination crisis. Through a systematic and quantitative review of the literature, we provide the first global assessment of pollinator responses to fire. We hypothesize that pollinators increase after fire and during the early postfire succession stages; however, high fire frequency has the opposite effect, decreasing pollinators.LocationTerrestrial ecosystems, excluding Antarctica.Time periodData collected from 1973 to 2017.Major taxa studiedInsects (Coleoptera, Diptera, Hymenoptera and Lepidoptera) and a few bird species.MethodsWe first compiled available studies across the globe that assessed fire effects on pollinator communities. Then, by means of hierarchical meta‐analyses, we evaluated how different fire regime parameters (fire frequency, postfire time and fire type) and habitat characteristics affect the abundance and richness of animals that act as pollinators. We also explored to what extent the responses vary among taxa groups and life history traits of pollinators (sociality system, nest location and feeding specialization), and among biomes.ResultsThe overall effect size of fire on pollinator abundance and richness across all studies was positive. Fire effect was especially clear and significant in early postfire communities, after wildfires, and for Hymenoptera. Taxonomic resolution influenced fire effects, where only studies at the species/genus and family levels showed significant effects. The main exceptions were recurrent fires that showed a negative effect, and especially wildfire effects on Lepidoptera abundance that showed a significant negative response.Main conclusionsPollinators tend to be promoted after a wildfire event. However, short fire intervals may threat pollinators, and especially lepidopterans. Given the current fire regime changes at the global scale, it is imperative to monitor postfire pollinators across many ecosystems, as our results suggest that fire regime is critical in determining the dynamics of pollinator communities.

Quantification of inter-regional differences in risk mitigation from prescribed burning across multiple management values

Fire agencies are moving towards planning systems based on risk assessment; however, knowledge of the most effective way to quantify changes in risk to key values by application of prescribed fire is generally lacking. We present a quantification and inter-regional comparison of how risk to management values responds to variations in prescribed burning treatment rate. Fire simulations were run using the PHOENIX RapidFire fire behaviour simulator for two case study landscapes in interface zones in Tasmania and the Australian Capital Territory (ACT), Australia. A Bayesian network approach used these data to explore the influence of treatment and weather on risk from wildfire. Area burnt, length of powerline damaged and length of road damaged responded more strongly to treatment in the ACT than in Tasmania, whereas treatment mitigated house loss and life loss more strongly in Tasmania than the ACT. The effect of prescribed burning treatment rate on area burnt below minimum tolerable fire interval was similar in each case study landscape. Our study shows that the effectiveness of prescribed burning at mitigating area burnt by wildfire and other key values varies considerably across landscapes and values.