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Ecosystems managed with contrasting fire regimes provide insight into the responses of vegetation and soil. Heathland, woodland and forest ecosystems along a gradient of resource availability were burnt over four decades in approximately 3‐ or 5‐year intervals or were unburnt for 45–47 years (heathland, woodland), or experienced infrequent wildfires (forest: 14 years since the last fire). We hypothesized that, relative to unburnt or infrequent fires, frequent burning would favour herbaceous species over woody species and resprouting over obligate seeder species, and reduce understorey vegetation height, and topsoil carbon and nitrogen content. Our hypothesis was partially supported in that herbaceous plant density was higher in frequently burnt vegetation; however, woody plant density was also higher in frequently burnt areas relative to unburnt/infrequently burnt areas, across all ecosystems. In heathland, omission of frequent fire resulted in the dominance of fern Gleichenia dicarpa and subsequent competitive exclusion of understorey species and lower species diversity. As hypothesized, frequent burning in woodland and forest increased the density of facultative resprouters and significantly reduced soil organic carbon levels relative to unburnt sites. Our findings confirm that regular burning conserves understorey diversity and maintains an understorey of lower statured herbaceous plants, although demonstrates the potential trade‐off of frequent burning with lower topsoil carbon levels in the woodland and forest. Some ecosystem specific responses to varied fire frequencies were observed, reflecting differences in species composition and fire response traits between ecosystems. Overall, unburnt vegetation resulted in the dominance of some species over others and the different vegetation types were able to withstand relatively high‐frequency fire without the loss of biodiversity, mainly due to high environmental productivity and short juvenile periods. [ABSTRACT FROM AUTHOR]

Fire alters habitat structure, thereby influencing fauna reliant on specific habitat features, particularly those with low dispersal capability such as reptiles. We quantified reptile responses to fire regimes in subtropical open eucalypt forests of southeast Queensland, Australia, with differing fire histories to isolate fire parameters that may alter reptile communities. We sampled 15 unique fire regimes from three sites. Active reptile searches and habitat assessments were completed at 74 plots to determine the influence of fire frequency, time since fire and fire type on reptile composition. The combination of fire parameters and habitat variables were key predictors of reptile communities within models. We identified a negative relationship for overall abundance and Lygisaurus foliorum with fire frequency, and higher species richness and abundances of two species in top disposal burn sites. Shrub and tree cover percentage were important predictors of three individual species. Concinnia martini also exhibited a negative response to time since fire. These results highlight the need to consider multiple fire parameters when explaining reptile community responses to fire owing to mixed responses and varied habitat preferences. Detailed recording and consideration of applied fire regimes should support adaptive management in relation to planned burning to support biodiversity outcomes. [ABSTRACT FROM AUTHOR]

Fire regimes are shifting under climate change. Decadal‐scale shifts in fire regime can disrupt the biogeochemical cycling of carbon (C), nitrogen (N), and phosphorus (P) within forest ecosystems, but the full extent of these disruptions is unknown. It is also unclear whether these disruptions have consequences for the ecological characteristics (e.g., biomass, abundance, and composition) of microbial and invertebrate communities, which together comprise the majority of terrestrial biodiversity and underpin many ecosystem processes. The theoretical framework of ecological stoichiometry has great potential in this context, but it has rarely been used to develop an integrated understanding of the biogeochemical and ecological effects of altered fire regime across trophic levels. Using one of the world's longest‐running fire experiments, located in Queensland, Australia, we carried out a comprehensive investigation into the stoichiometric consequences of a decadal‐scale divergence in prescribed fire frequency and their links to coinciding changes in various ecological characteristics of forest floor microbial and invertebrate communities. Compared to long‐term fire exclusion, forty‐three years of biennial burning led to significantly N‐depleted and/or P‐enriched stoichiometry in soil, leaf litter, leaf litter–associated microbial biomass, and certain groups of invertebrates, although total invertebrate community stoichiometry was not affected. Microbial biomass was 42% lower in biennially burned soils. Invertebrate community composition differed between fire regime treatments on some sampling dates, but fire regime did not have consistent effects on invertebrate biomass or abundance. Microbial biomass and the abundances of some invertebrate taxa were depressed at particularly low and/or high resource N:P, consistent with a coupling of these variables to the stoichiometric effects of decadal‐scale fire regime. Litter transplants likewise indicated that some invertebrate abundances were sensitive to litter properties over 12 months. Together, our results indicate that long‐term changes in fire regime can decouple the within‐ecosystem cycling of N and P, with N and P cycling growing more and less conservative, respectively, under high‐frequency fire in a way that propagates throughout forest floor food webs. Our study provides new insights into the coupled biogeochemical and ecological responses of forest ecosystems to novel fire regimes and establishes a basis for a stoichiometric framework for fire ecology. [ABSTRACT FROM AUTHOR]

This paper identifies key fire history and fire-related spatial databases that can be utilised for effective planning and assessment of prescribed burns in south-eastern Queensland. To ensure that appropriate fire regimes are maintained for specific management objectives (e.g. biodiversity conservation or risk management), and to assist fire managers with planning prescribed fire and post-fire assessments, we describe, using case studies and existing tools, the application of remote sensing data and derived burned area products together with field data to potentially: (1) improve mapping of fire-prone areas; (2) improve the accuracy of mapping burned areas; (3) monitor temporal changes in fuel structure; and (4) map post-fire severity. This study utilised data collected from aerial and satellite-based multispectral, microwave and laser (LiDAR) sensors. There are several spatial databases and analytical methods available that are not currently used by fire management agencies in this region. For example, the methods to estimate fuel, such as LiDAR, are underutilised and unburned patches within a burned area are not routinely mapped. Better use of spatial datasets could lead to an improved understanding of variables such as fuel status, resulting in more efficient use of fire management resources. Using case studies from the south-east Queensland bioregion, this study demonstrates the relevance of diverse spatial databases for prescribed burn planning, implementation and adaptive monitoring of operational targets. Comparison between available resources and actual burn practices has identified the potential for improved use of spatial databases for holistic fire management. [ABSTRACT FROM AUTHOR]

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 (148 563 ha), whereas 58.8% of melaleuca communities (8016 ha) and 66.6% of plantations (2442 ha) 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. Using past fire records, we identified planned and unplanned fire occurrences between 2004 and 2015 in south-east Queensland. Unplanned fires covered a larger extent, were more frequent and occurred mostly in spring, whereas planned fires occurred mostly in winter. The use of accurate fire records in mapping enhances fire management capabilities. [ABSTRACT FROM AUTHOR]

Abstract Changes in fire regime and soil temperatures will be simultaneous symptoms of climate change in many regions around the world, yet very few studies have investigated how these factors will interact to affect soil carbon (C) cycling. Interacting effects of fire regime and temperature on soil C cycling processes might constitute an important but poorly-understood feedback to the global climate system. Using soils from one of the world's longest running prescribed fire trials in eastern Australia, we investigated the effect of fire regime on the rate, energetic efficiency, and temperature sensitivity of soil heterotrophic respiration and associated properties across a range of incubation temperatures (15 °C, 25 °C, and 35 °C). Levels of total, labile, soluble, and microbial biomass C were 32%, 59%, 64%, and 38% lower, respectively, in biennially-burned (2yB) soils than in soils that had not been exposed to fire since 1969 (NB soils). Moreover, while rates of heterotrophic respiration did not vary among NB, 2yB or quadrennially-burned (4yB) soils during the 55-day incubation period, values of q CO 2 (which are inversely related to microbial energetic efficiency) were 59.8% higher in 2yB soils than in NB soils. This suggests that biennial-burning is associated with soil conditions that promote energetic inefficiency in the microbial community and highlights the role of environmental stress as a determinant of respiratory responses to fire regime. Respiration temperature sensitivity (i.e. Q 10 values) of 2yB soils was 86% greater than that of 4yB soils at the temperature range of 15–25 °C. This effect was absent at the temperature range of 25–35 °C and in soils to which labile C levels had been boosted through glucose addition. This pattern in Q 10 values might be attributed to low quality soil organic matter in 2yB soils in combination with mechanisms associated with microbial community structure. Together these results enhance our understanding of C cycling in fire-affected soils and suggest a potentially important positive feedback between fire, climate change, and the terrestrial C cycle that warrants further investigation. Highlights • Biennially-burned (2 yB) soils had lower levels of carbon than unburned (NB) soils. • Energetic efficiency of microbial biomass was lower in 2 yB than NB soils. • Overall rates of heterotrophic CO 2 respiration were not affected by fire regime. • Fire regime affected respiration temperature sensitivity between 15 and 25 °C. • Temperature and fire regime interacted to affect microbial biomass stoichiometry. [ABSTRACT FROM AUTHOR]

Fire is a common feature of Australian forests and prescribed burning is a routine management strategy, often utilised to mitigate the effects of wildfire. However, the impacts of fire on terrestrial invertebrates are poorly understood. Here we provide an overview of continuing long-term fire studies in temperate and sub-tropical forest ecosystems, with a focus on terrestrial invertebrates. Longitudinal fire study sites exist in southern Queensland, New South Wales, Victoria, Western Australia and Tasmania. Most studies have focussed on fire frequency and have identified certain taxa or taxonomic groups that prefer either habitat associated with long unburnt areas, habitat associated with more frequently burnt areas or those that show no response to varied fire frequency. The limited number of studies investigating fire season report similar findings, but there are few studies that have focussed on other components of the fire regime. Long-term experiments are important when studying the effects of various fire regimes on invertebrate assemblages as responses often take time to be expressed, and may follow changes in habitat availability associated with interactions between components of the fire regime. We recommend that ecological studies continue to utilise long-term study sites through monitoring programs to improve our understanding of how invertebrate taxa respond to fire regimes; and to better identify the important role of invertebrate groups in ecosystem functioning (e.g. for nutrient cycling, pollination). [ABSTRACT FROM AUTHOR]

Prescribed burning has been widely used in the management of forests for reducing wildfire risk, and can have significant effects on soil carbon (C) and nitrogen (N) pools and their temporal changes. This study aimed to investigate the impacts of different burning frequency regimes on the temporal dynamics of C and N in the topsoil and forest floors. The experimental site was a 39 year old wet scherophyll forest prescribed burning trial at Peachester, southeast Queensland, Australia, with treatments of no burning (NB) since 1969, 2 yearly burning (2yrB) and 4 yearly burning (4yrB) since 1972. Each of three burning treatments had four replications and these plots were randomly distributed over an area of the forest with similar vegetation and soil characteristics. Soil (0–10 cm) and forest floors were sampled monthly for 6 months prior to the next scheduled burning for both burning treatments to minimize the effects of fire recency. Prescribed burning significantly ( P < 0.01) affected most C and N variables in both soils and forest floors. The 2yrB treatment had significantly lower ( P < 0.01) soil total C, total C:N ratio, microbial biomass C (MBC) and N (MBN), MBC:MBN ratio, dissolved organic C (DOC) and N (DON), NO 3 − -N , inorganic N and L layer total N, DON and NO 3 − -N , compared with the NB and 4yrB treatments. However, there were no overall significant differences in these variables between the NB and 4yrB treatments. Sampling month significantly ( P < 0.01) affected C and N variable in both soils and forest floors except for soil total C and N and F layer MBC. Temporal dynamics of most of these labile C and N variables were highly related to soil and forest floor moisture content, seven day mean air temperature (MAT) and cumulative rainfall prior to sampling date. However, fire effects were independent of sampling month, as there were no significant interactions between them for most response variables measured. This study has clearly demonstrated that more frequent burning (2 yr burning) had negative impact on soil and forest floor C and nutrient pools. Insignificant differences observed in soil C and N and forest floor N pools between less frequent burning (4yrB) and NB treatments highlighted that the prescribed burning at four year interval gave sufficient time for recovery of these soil and forest floor nutrients to pre-burn levels. [ABSTRACT FROM AUTHOR]

Low-intensity prescribed burning is a common forest management tool and plays a major role in modifying biogeochemical cycling through the alteration of substrate availability and microbial communities. In this study, we assessed the response of microbial community to repeated prescribed burning in two sclerophyll forests (the Bauple site, dry, annual rainfall 1000 mm; and the Peachester site, wet, 1711 mm) in southeast Queensland, Australia. At the dry sclerophyll forest (the Bauple site), annual and triennial burning did not significantly alter the soil carbon (C) and nitrogen (N) content, while at the wet scleophyll forest (the Peachester site), two yearly burnings resulted in significantly lower soil total C and N contents compared to the long unburnt treatment. In spite of these different responses, prescribed burning regimes did not significantly influence the abundance of 16S rRNA or denitrifying gene (narG,nirK,nirS,nosZ) at both sites. These results indicated that, long-term prescribed burning has little effect on the denitrifying communities, while it has varying effects on soil chemical properties at the two sites, which are likely to be explained by differences in vegetation type and soil moisture regime. [ABSTRACT FROM AUTHOR]

We compared selectively harvested and unharvested areas located among treatments of annual burning since 1952, triennial burning since 1973 and an area that had received no prescribed burning, but with a single wildfire in 2006 (one fire in 72 years), in a dry sclerophyll eucalypt forest, south-eastern Queensland, Australia. Historic fire regime, rather than low-intensity, selective timber harvesting (17% to 37% live tree basal area removed) had a greater impact on a range of vegetation and soil attributes. Plant taxa composition was influenced more by historic fire regime than recent harvesting; of the 25.5% of the variation in taxa composition explained, fire treatments alone accounted for 96.4% of the explained variation and harvesting alone accounted for just 4.8%. Selective harvesting of timber had a predictable influence associated with removal of tree cover and physical impacts associated with extraction of logs. In harvested areas there were increases (p < 0.05) in bare-ground cover and in coarse woody debris volumes and decreases in understorey vegetation height, particularly where woody understorey was present. However, overall, the combined effects of timber harvesting and fire regime were relatively minor. These sub-tropical dry eucalypt forests appear to be resilient to the impacts of combined, but low-intensity disturbances. [ABSTRACT FROM AUTHOR]

• Frequent prescribed burning was applied over 45 years at a long running experiment. • Annual burning encouraged tree diameter growth rates. • Stand basal area had a negative influence on tree growth rates. • Triennial burning enhanced tree recruitment, resulting in higher tree densities. Frequent fire often has a negative impact of tree recruitment and growth. Tree growth rates, density and recruitment were compared among treatments of annual burning since 1952, triennial burning since 1973 and no burning (1946 to 1996) or single wildfire (1996 to 2018), in a dry sclerophyll eucalypt forest, south-eastern Queensland, Australia. Tree diameter (at breast height, DBH) growth rates were greater in the annually burnt treatment than in the triennially burn and single wildfire treatments over the period from 1974 to 2018, and these differences were also apparent pre-wildfire (period from 1974 to 1996). In the period from 1996 to 2018, the annually burnt treatment had greater DBH growth relative to the single wildfire treatment, but the triennial treatment had intermediate growth rates. Competitive interactions between trees (assessed using plot basal area) also had a negative impact on individual tree growth rates. The impacts of different fire regimes at this site on tree crown health were not apparent (P > 0.05) and there was only limited evidence that differences in growth rates were due to differences in soil nutrients (marginally higher topsoil phosphorus in the frequently burnt treatments, P = 0.075). Greater tree growth rates in the annually burnt treatment may be related to the lower density of understorey woody plants in this treatment and potentially reduced competition for soil moisture. The density of trees (DBH ≥ 10 cm) in 2018 was surprisingly higher in the triennially burnt treatment (381 stems/ha) relative to both the annually burnt (192 stems/ha) and single wildfire (234 stems/ha) treatments. This was largely due a higher level of recruitment over time and a higher density of stems 10–20 cm DBH in triennially burnt plots. Concerns regarding the impacts of frequent prescribed fire on tree recruitment and growth may be unwarranted in these remarkably resilient dry eucalypt forests. [ABSTRACT FROM AUTHOR]

Decadal‐scale increases in fire frequency have the potential to deplete ecosystems of essential nutrients and consequently impede nutrient‐limited biological processes via stoichiometric imbalance. Decomposition, a fundamental ecosystem function and strong driver of future fire occurrence, is highly sensitive to nutrient availability and is, therefore, particularly important in this context. Here we show that 40 yr of quadrennial (4yB) and biennial (2yB) prescribed burning result in severely P‐ and N‐depleted litter stoichiometry, respectively, relative to fire exclusion. These effects exacerbated the nutrient limitation of microbial activities, constraining litter decomposition by 42.1% (4yB) and 23.6% (2yB) relative to unburned areas. However, invertebrate‐driven decomposition largely compensated for the diminished capacity of micro‐organisms under 4yB, suggesting that invertebrates could have an important stabilizing influence in fire‐affected ecosystems. This effect was strongly positively coupled with the strength of microbial P‐limitation and was not obviously or directly driven by fire regime‐induced changes in invertebrate community assemblage. Together, our results reveal that high‐frequency fire regimes promote nutrient‐poor, carbon‐rich ecosystem stoichiometry and, in doing so, disrupt ecosystem processes and modify the relative functionality of micro‐organisms and invertebrates. [ABSTRACT FROM AUTHOR]

Prescribed fire is one of the most widely-used management tools for reducing fuel loads in managed forests. However the long-term effects of repeated prescribed fires on soil carbon (C) and nitrogen (N) pools are poorly understood. This study aimed to investigate how different fire frequency regimes influence C and N pools in the surface soils (0–10 cm). A prescribed fire field experiment in a wet sclerophyll forest established in 1972 in southeast Queensland was used in this study. The fire frequency regimes included long unburnt (NB), burnt every 2 years (2yrB) and burnt every 4 years (4yrB), with four replications. Compared with the NB treatment, the 2yrB treatment lowered soil total C by 44%, total N by 54%, HCl hydrolysable C and N by 48% and 59%, KMnO 4 oxidizable C by 81%, microbial biomass C and N by 42% and 33%, cumulative CO 2 –C by 28%, NaOCl-non-oxidizable C and N by 41% and 51%, and charcoal-C by 17%, respectively. The 4yrB and NB treatments showed no significant differences for these soil C and N pools. All soil labile, biologically active and recalcitrant and total C and N pools were correlated positively with each other and with soil moisture content, but negatively correlated with soil pH. The C:N ratios of different C and N pools were greater in the burned treatments than in the NB treatments. This study has highlighted that the prescribed burning at four year interval is a more sustainable management practice for this subtropical forest ecosystem. [ABSTRACT FROM AUTHOR]

Abstract: Production of nitrous oxide (N2O) by anaerobic denitrification is one of the most important processes in the global nitrogen (N) cycle and has attracted recent attention due to its significant impacts on climatic change. Fire is a key driver of many ecosystem processes, however, how fire drives the shift in microbial community and thus alters nutrient cycling is still unclear. In this study, a 35-year-old repeated prescribed burning trial, with three treatments (no burning, 2 yearly burning and 4 yearly burning), was used to explore how the long-term repeated prescribed burning affects N2O flux, key soil properties (inorganic N, dissolved organic carbon (DOC) and N, pH, electrical conductivity (EC), moisture), denitrification gene abundance and their interactions. Soil samples were collected in January and April 2011. Quantitative real-time PCR was employed to quantify the gene copy number of target genes, including narG, nirK, nirS and nosZ. In situ N2O fluxes ranged from 0 to 8.8 g N2O–N ha−1 h−1 with an average of 1.47 g N2O–N ha−1 h−1. More frequent fire (2 yearly burning) significantly reduced soil N2O fluxes, availability of C and N substrates and moisture, but increased soil pH and EC compared with no burning and 4 yearly burning treatments. Fire treatments did not significantly affect the abundance of most denitrification genes. There were no significant differences in most parameters measured between the 4 yearly burning and no burning treatments, indicating microbial community function is not affected by less frequent (4 year interval) burning. Variation in the N2O fluxes among the treatments can largely be explained by soil substrate (, DOC and total soluble nitrogen (TSN)) availability and soil environmental factors (pH, EC, and moisture), while the abundance of most denitrification genes were not related to the N2O fluxes. It is concluded that soil environmental factors rather than denitrification gene abundance control N2O fluxes in this wet sclerophyll forest in response to long-term repeated fires. [Copyright &y& Elsevier]