@article {bnh-7311, title = {Seasonal fine fuel and coarse woody debris dynamics in north Australian savannas}, journal = {International Journal of Wildland Fire}, year = {2020}, month = {09/2020}, abstract = {

Several studies have separately explored accumulation of the dominant fuels (grass, fine litter (\<6 mm diameter) and coarse woody debris (CWD, 6{\textendash}50 mm diameter)) in north Australian savannas. We report an analysis of two longitudinal datasets describing how these three fuel components covary in abundance throughout the year in eucalypt-dominated savanna over a rainfall gradient of 700{\textendash}1700 mm mean annual rainfall (MAR). Our observations concur generally with previous observations that litter accumulation results in a late dry season (LDS) peak in biomass, whereas cured grassy fuels typically are seasonally invariant, and CWD inputs are associated with stochastic severe wet season storms and dry season fires. The distinct LDS litter peak contributes significantly to the potential for LDS fires to be of higher intensity, burn more fuel per unit area and produce greater emissions relative to early dry season (EDS) fires. However, Australia{\textquoteright}s current (2018) formal savanna burning emissions avoidance methodology erroneously deems greater EDS fine fuel (grass and fine litter) biomass in four of nine designated vegetation fuel types. The study highlights the need to develop seasonally dynamic modelling approaches that better account for significant seasonal variation in fine fuel inputs and decomposition.

}, keywords = {emissions abatement, fire management, fire regime, fire seasonality, foliage projective cover, fuel accumulation, litter fuels, tropical savanna}, doi = {https://doi.org/10.1071/WF20073}, url = {https://www.publish.csiro.au/wf/WF20073}, author = {Yates, Cameron P. and Harry MacDermott and Jay Evans and Murphy, Brett P. and Jeremy Russell-Smith} } @article {bnh-5417, title = {Delivering effective savanna fire management for defined biodiversity conservation outcomes: an Arnhem Land case study}, journal = {International Journal of Wildland Fire}, year = {2019}, month = {02/2019}, abstract = {

Given the recent history of frequent and extensive late dry season wildfire in Australia{\textquoteright}s fire-prone northern savannas, regional conservation-based fire management programs typically aim to mitigate wildfire through the use of strategic prescribed burning during the cooler early dry season. However, it remains unclear as to the extent such environmental management concerns are being addressed by these renewed fire management efforts. This study documents changes in fire regime in the western Arnhem Land region of northern Australia associated with the implementation of active fire management since 2006. Over a 12-year period, the regional fire regime has transitioned from late dry season, wildfire-dominated to being characterised by a majority of fires occurring as small early dry season prescribed burns. Although overall area burnt has not significantly decreased, most ecological threshold metrics have improved, with the exception of those describing the maintenance of longer-unburnt habitat. Challenges involved with defining, delivering, monitoring and evaluating heterogeneity targets are discussed.

}, keywords = {ecological thresholds, fire regimes, Prescribed burning}, doi = {https://doi.org/10.1071/WF18126}, url = {http://www.publish.csiro.au/WF/WF18126}, author = {Jay Evans and Jeremy Russell-Smith} } @article {bnh-6052, title = {Tree recruitment dynamics in fire-prone eucalypt savanna}, journal = {Ecosphere}, volume = {10}, year = {2019}, month = {03/2019}, pages = {e02649}, abstract = {

Savanna sites are idealized as exhibiting a demographic {\textquotedblleft}bottleneck{\textquotedblright} physiognomy comprising a lower stratum of abundant resprouting persistent {\textquotedblleft}juveniles{\textquotedblright} (albeit of indeterminate age), a mid-stratum comprising relatively few released {\textquotedblleft}saplings,{\textquotedblright} and a canopy-layer cohort of {\textquotedblleft}adults.{\textquotedblright} The magnitude and frequency of disturbance is considered to influence the critical transition from juvenile into adult phases. Under fire-prone Australian savanna conditions, an extensive suite of both observational and manipulative studies have explored the responses of tree recruitment to fire disturbances. These studies oftentimes have produced seemingly highly disparate responses, particularly with respect to the differential responses of relatively fast-growing eucalypts versus non-eucalypts under different fire regime, and overstory competition, conditions. This study contrasts the responses of tree recruitment height classes to (1) the effects of total canopy removal from severe Cyclone Monica in 2006 over a subsequent 10-yr period, (2) with observations from long-term monitoring sites under relatively stable overstory conditions at Litchfield National Park over a six-year period, (3) under ambient, frequent fire occurrence (mean \> 0.5 fires/yr) at both locales including relatively severe late dry season fires. Recruitment at both study sites was represented mostly by resprouting, clonally reproducing juvenile trees \<2 m tall, around half of which died over respective assessment periods. At post-cyclone assessment plots, there was substantial release of eucalypts, including within the first five years, into the \>5 m height class, with negligible corresponding release of non-eucalypts. At Litchfield plots, there was negligible release of both eucalypts and non-eucalypts. In discussion, we contrast these results with findings from relevant regional studies. We contend that collective disparate observations feasibly can be reconciled as reflecting significant interactions between fire regime characteristics and variable site overstory competition effects, such that the rate of recruitment of fast-growing savanna eucalypt individuals into the midstory is relatively independent of the fire regime, but is significantly regulated by resource competition interactions especially with the overstory, whereas recruitment of non-eucalypts is relatively independent of overstory competitive effects, but is suppressed under fire regimes dominated by frequent, especially severe fires.

}, keywords = {Australia; canopy competition; cyclone disturbance; density dependence; eucalypt; fire disturbance; fire regime; juveniles; recruitment dynamics; resprouts; saplings; savanna.}, doi = {https://doi.org/10.1002/ecs2.2649}, url = {https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.2649}, author = {Jeremy Russell-Smith and Jay Evans and Harry MacDermott and Brocklehurst, Peter and Schatz, Jon and Erin Lynch and Yates, Cameron P. and Andrew C. Edwards} } @article {bnh-6041, title = {Incentivising fire management in Pindan (Acacia shrubland): A proposed fuel type for Australia{\textquoteright}s Savanna burning greenhouse gas emissions abatement methodology}, journal = {Ecological Management \& Restoration}, volume = {19}, year = {2018}, month = {08/2018}, pages = { 230-238}, abstract = {

The Australian Government has sanctioned development of greenhouse gas emissions (GHG) abatement methodologies to meet international emissions reduction obligations. Savanna burning emissions abatement methodologies have been available since 2012, and there are currently 72 registered projects covering approximately 32 million ha. Abatement to date has exceeded 4 million tonnes of carbon dioxide equivalent (CO2-e) principally through the application of low intensity early dry season fire management to reduce the amount of biomass combusted in higher intensity late dry season (LDS) fires. Savanna burning projects can only be conducted on areas with eligible fire-prone vegetation fuel types where implementing the improved fire management regime is considered ecologically appropriate. This study assesses the suitability of including tall\ Acacia\ shrublands ({\textquoteleft}Pindan{\textquoteright}) as a new eligible fuel type. These shrublands make up 12\% (~2 million ha) of the Kimberley region, Western Australia, where, on average, 32\% is fire affected annually, mostly in the LDS. A standard assessment protocol was applied to describe vegetation fuel type structural and pyrolysis characteristics. We show that Pindan (i) can be identified and mapped as a unique tall\ Acacia\ shrubland vegetation fuel type, (ii) characterised by a significantly greater shrubby fuel load biomass, and (iii) the conservation status of which would benefit from imposition of strategic prescribed burning programme. Savanna burning projects in the Pindan fuel type could potentially abate up to 24.43\ t.CO2-e/km2\ per year, generating significant income and employment opportunities for predominantly Indigenous land managers in the region.

}, keywords = {Abatement, fire management, Savanna}, doi = {https://doi.org/10.1111/emr.12334}, url = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/emr.12334}, author = {Erin Lynch and Jeremy Russell-Smith and Andrew C. Edwards and Jay Evans and Yates, Cameron P.} } @article {bnh-5144, title = {Assessing ecological performance thresholds in fire-prone Kakadu National Park, northern Australia}, journal = {Ecosphere}, volume = {8}, year = {2017}, month = {07/2017}, abstract = {

Contemporary fire regimes are recognized as a key threatening process for relatively immobile vertebrates and narrowly dispersing obligate seeder plant taxa in fire-prone Australian savannas. Here, we assess the efficacy of proposed ecological performance threshold metrics for evaluating the current state of fire management for biodiversity conservation outcomes in Australia{\textquoteright}s premier, and best publicly funded savanna reserve, Kakadu National Park. The assessment draws on available data describing Landsat-scale fire mapping over the period 1997{\textendash}2015, habitat mapping, and mostly modeled responses of vegetation and faunal attributes. Despite conceptual and technical issues associated with various proposed performance thresholds and mapping products, the assessment demonstrates significant challenges with the current state of the reserve{\textquoteright}s fire management program. For example, by the end of 2015 it was observed that just 6\% of woodland habitat in lowland and 23\% in upland situations had remained unburnt for longer than three years and 98\% of mapped fires in lowland and 87\% in upland habitats were \>1\ km2\ in extent. Of 14 assessed performance threshold metrics, two were within acceptable thresholds at the end of 2015, and none had improved materially over the decadal assessment period. Given substantial resources evidently required to deliver effective, seasonally intensive, fine-grained adaptive fire management for biodiversity conservation outcomes in fire-prone Australian savannas, we suggest that alternative resourcing opportunities through market-based savanna burning greenhouse gas emissions abatement projects need to be explored.

}, doi = {https://doi.org/10.1002/ecs2.1856}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.1856}, author = {Jeremy Russell-Smith and Jay Evans and Andrew C. Edwards and Anthony Simms} }