Carbon markets afford potentially useful opportunities for supporting socially and environmentally sustainable land management programs but, to date, have been little applied in globally significant ...fire-prone savanna settings. While fire is intrinsic to regulating the composition, structure and dynamics of savanna systems, in north Australian savannas frequent and extensive late dry season wildfires incur significant environmental, production and social impacts. Here we assess the potential of market-based savanna burning greenhouse gas emissions abatement and allied carbon biosequestration projects to deliver compatible environmental and broader socio-economic benefits in a highly biodiverse north Australian setting. Drawing on extensive regional ecological knowledge of fire regime effects on fire-vulnerable taxa and communities, we compare three fire regime metrics (seasonal fire frequency, proportion of long-unburnt vegetation, fire patch-size distribution) over a 15-year period for three national parks with an indigenously (Aboriginal) owned and managed market-based emissions abatement enterprise. Our assessment indicates improved fire management outcomes under the emissions abatement program, and mostly little change or declining outcomes on the parks. We attribute improved outcomes and putative biodiversity benefits under the abatement program to enhanced strategic management made possible by the market-based mitigation arrangement. For these same sites we estimate quanta of carbon credits that could be delivered under realistic enhanced fire management practice, using currently available and developing accredited Australian savanna burning accounting methods. We conclude that, in appropriate situations, market-based savanna burning activities can provide transformative climate change mitigation, ecosystem health, and community benefits in northern Australia, and, despite significant challenges, potentially in other fire-prone savanna settings.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Tropical savannas are characterized by high primary productivity and high fire frequency, such that much of the carbon captured by vegetation is rapidly returned to the atmosphere. Hence, there have ...been suggestions that management‐driven reductions in savanna fire frequency and/or severity could significantly reduce greenhouse gas emissions and sequester carbon in tree biomass. However, a key knowledge gap is the extent to which savanna tree biomass will respond to modest shifts in fire regimes due to plausible, large‐scale management interventions. Here, we: (1) characterize relationships between the frequency and severity of fires and key demographic rates of savanna trees, based on long‐term observations in vegetation monitoring plots across northern Australia; (2) use these relationships to develop a process‐explicit demographic model describing the effects of fire on savanna tree populations; and (3) use the demographic model to address the question: to what extent is it feasible, through the strategic application of prescribed burning, to increase tree biomass in Australian tropical savannas? Our long‐term tree monitoring dataset included observations of 12,344 tagged trees in 236 plots, monitored for between 3 and 24 years. Analysis of this dataset showed that frequent high‐severity fires significantly reduced savanna tree recruitment, survival, and growth. Our demographic model suggested that: (1) despite the negative effects of frequent high‐severity fires on demographic rates, savanna tree biomass appears to be suppressed by only a relatively small amount by contemporary fire regimes, characterized by a mix of low‐ to high‐severity fires; and (2) plausible, management‐driven reductions in the frequency of high‐severity fires are likely to lead to increases in tree biomass of about 11.0 t DM ha−1 (95% CI: −1.2–20.8) over a century. Accounting for this increase in carbon storage could generate significant carbon credits, worth, on average, three times those generated annually by current greenhouse gas (methane and nitrous oxide) abatement projects, and has the potential to significantly increase the economic viability of fire/carbon projects, thereby promoting ecologically sustainable management of tropical savannas in Australia and elsewhere. This growing industry has the potential to bring much‐needed economic activity to savanna landscapes, without compromising important natural and cultural values.
Savannas are the most fire-prone of the earth's major biomes. The availability of various broad-scale satellite-derived fire mapping and regional datasets provides a framework with which to examine ...the seasonality, extent and implications of large fires with particular reference to biodiversity values in the tropical savannas of northern Australia. We document the significance of savanna fires in the fire-prone 'Top End' region of the Northern Territory, Australia, using 9 years (1997-2005) of National Oceanic and Atmospheric Administration (NOAA)-Advanced Very High Resolution Radiometer (AVHRR)-, Landsat Thematic Mapper (TM)- and Enhanced Thematic Mapper (ETM+)-derived fire mapping. Fire (patch) sizes from both AVHRR- and Landsat-scale mapping increased through the calendar year associated with progressive curing of grass and litter fuels. Fire frequency data at both satellite sensor scales indicate that regional fire regimes in higher rainfall regions are dominated by large (>1000 km²) fires occurring typically at short (~2-3 years) fire return intervals. In discussion, we consider the ecological implications of these patch size distributions on regional fire-sensitive biota. Collectively, assembled data illustrate that many northern Australian savanna flora, fauna and habitats embedded within the savanna matrix are vulnerable to extensive and frequent fires, especially longer-lived obligate seeder plant taxa and relatively immobile vertebrate fauna with small home ranges.
Aim: Building on a substantial literature addressing the fire responses of woody plants, particularly under mediterranean climates, we assess the extent to which fire persistence traits can be used ...to predict vegetation responses to fire regime changes in fire-prone arid and savanna landscape settings. Location: Australia, applying data from arid central to monsoonal northern regions (11–26° S, 129–138° E). Methods: With reference to a substantial sub-continental floristics dataset, we first assigned the fire response (obligate seeder, resprouter) and seedbank persistence (transient, dormant) of rapid and longer-maturing (> 3 years) woody taxa. Using logistic regression, we then modelled the proportions of taxa possessing these traits as a function of mean annual rainfall (highly correlated with fire frequency) and terrain roughness (a measure of topographic variability) in 0.25° x 0.25° and 1° x 1° grid cells. Separate assessments were undertaken with datasets for 1264 sclerophyll and 236 rain forest taxa. Results: This woody flora is characterized by taxa exhibiting mostly resprouting and dormant seedbank traits that promote site persistence. While numbers of obligate seeder and resprouter taxa were related positively to both rainfall and roughness, the relative abundance of both sclerophyll and rain forest obligate seeders decreased significantly with rainfall. The relative abundance of sclerophyll (especially long-lived) obligate seeders alone increased with topographic roughness. The proportion of taxa with transient seedbanks increased with rainfall in resprouters generally, and in rain forest obligate seeders alone. Main conclusions: We find that resprouters are favoured on more productive, fire-prone sites, and obligate seeders are favoured in less productive, more fireprotected settings. Seedbank persistence responses are more variable. These findings concur generally with theoretical constructs, and support comparable assessments in Australian and other fire-prone systems ranging from mediterranean to boreal environments. Our observations illustrate that resprouting and obligate seeding syndromes, but not necessarily seedbank persistence, are useful predictors of vegetation responses to changing fire regime conditions at large landscape scales.
Few data are available concerning contemporary fire regimes and the responses of fire interval-sensitive vegetation types in semiarid woodland savanna landscapes of northern Australia. For a 10300km² ...semiarid portion of Gregory National Park, in the present paper we describe (1) components of the contemporary fire regime for 1998-2008, on the basis of assessments derived from Landsat and MODIS imagery, (2) for the same period, the population dynamics, and characteristic fine-fuel loads associated with Acacia shirleyi Maiden (lancewood), an obligate seeder tree species occurring in dense monodominant stands, and (3) the fire responses of woody species, and fine-fuel dynamics, sampled in 41 plots comprising shrubby open-woodland over spinifex hummock grassland. While rain-year (July-June) rainfall was consistently reliable over the study period, annual fire extent fluctuated markedly, with an average of 29% being fire affected, mostly in the latter part of the year under relatively harsh fire-climate conditions. Collectively, such conditions facilitated short fire-return intervals, with 30% of the study area experiencing a repeat fire within 1 year, and 80% experiencing a repeat fire within 3 years. Fine fuels associated with the interior of lancewood thickets were characteristically small (10 years. Of 133 woody species sampled, all trees (n=26), with the exception of A. shirleyi, were resprouters, and 58% of all shrub species (n=105) were obligate seeders, with observed primary juvenile periods <5 years. Assembled data generally supported observations made from other northern Australian studies concerning the responses of fire-sensitive woody taxa in rugged, sandstone-derived landscapes, and illustrated the enormous challenges facing ecologically sustainable fire management in such settings. Contemporary fire regimes of Gregory National Park are not ecologically sustainable.
The development of continental-scale fire mapping using AVHRR since the early 1990s and, more recently, MODIS imagery, is transforming our understanding of Australian fire regimes--particularly the ...national significance of savanna burning. The savannas of northern Australia are the most fire-prone part of a fire-prone continent. The savanna region comprises 1,898,562 km2 (24.7% of the Australian landmass), of which 21% has been burnt on average each year, over the period 1997-2005. Savanna fires currently contribute about 68% of national fire extent annually--the remainder comprising mostly fire in central Australia (associated in recent years with decadally high rainfall, hence high fuel loads), with just 2% in relatively densely populated southern Australia. At finer scales of resolution employing LANDSAT imagery, northern Australian studies since the early 1980s are providing novel landscape-scale assessments including monitoring of fire regime heterogeneity and biomass burning emissions. While seasonality has been shown in a number of studies to be correlated with fire intensity, remote sensing studies of fire severity are just commencing. The paper particularly addresses recent north Australian studies that explore the importance of spatial and temporal patchiness in fire extent and severity.
The emerging discipline of bacterial glycoengineering has made it possible to produce designer glycans and glycoconjugates for use as vaccines and therapeutics. Unfortunately, cell-based production ...of homogeneous glycoproteins remains a significant challenge due to cell viability constraints and the inability to control glycosylation components at precise ratios in vivo. To address these challenges, we describe a novel cell-free glycoprotein synthesis (CFGpS) technology that seamlessly integrates protein biosynthesis with asparagine-linked protein glycosylation. This technology leverages a glyco-optimized Escherichia coli strain to source cell extracts that are selectively enriched with glycosylation components, including oligosaccharyltransferases (OSTs) and lipid-linked oligosaccharides (LLOs). The resulting extracts enable a one-pot reaction scheme for efficient and site-specific glycosylation of target proteins. The CFGpS platform is highly modular, allowing the use of multiple distinct OSTs and structurally diverse LLOs. As such, we anticipate CFGpS will facilitate fundamental understanding in glycoscience and make possible applications in on demand biomanufacturing of glycoproteins.
BMK1 is activated by mitogens and oncogenic signals and, thus, is strongly implicated in tumorigenesis. We found that BMK1 interacted with promyelocytic leukemia protein (PML), and inhibited its ...tumor-suppressor function through phosphorylation. Furthermore, activated BMK1 notably inhibited PML-dependent activation of p21. To further investigate the BMK-mediated inhibition of the tumor suppressor activity of PML in tumor cells, we developed a small-molecule inhibitor of the kinase activity of BMK1, XMD8-92. Inhibition of BMK1 by XMD8-92 blocked tumor cell proliferation in vitro and significantly inhibited tumor growth in vivo by 95%, demonstrating the efficacy and tolerability of BMK1-targeted cancer treatment in animals.
► Development of a potent inhibitor, XMD8-92, for BMK1 kinase ► XMD8-92 significantly inhibits tumor growth in animal ► BMK1 inhibits p21 expression through PML
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