The forest in motion : exploratory studies in Western Arnhem Land, Northern Australia

As a contribution to academic debate concerning northern Australian vegetation ecology and history, and as a contribution also to contemporary land management issues in that region, the findings of various biogeographical, ecological and ethnobotanical studies are presented here which, collectively, explore the status of monsoon vine-forest (MVF) vegetation in the western Arnhem Land region of the Northern Territory. Structurally, the thesis comprises five papers presented in the chronological sequence of their completion, and a brief, explanatory introduction. The first paper, written early in the field-work programme and presented at a northern Australian symposium focusing on current ecological research in the region, describes vegetation changes associated with the advent of European ecological influence in western Arnhem Land (i·e. within the last 100 or so years), at Giina, a traditional Aboriginal camp-site on the edge of the South Alligator River. The paper describes the elimination of MVF at Giina, qnd its reduction elsewhere in the local area, within the recent, historical past. The paper concludes that the destruction of such vegetation is attributable to feral animal impact and changes to the burning regime. These themes are developed in subsequent papers. Whilst still on field work, and having been approached to present a position paper on MVF in the Northern Territory, the second paper, co-authored with Clyde Dunlop, attempts "to provide an account of the ecology (so far as is known), the condition and the conservation status of monsoon vine-forests in the Northern Territory". This paper challenges the generally accepted view that the scattered distribution of small, discrete patches of MVF across northern Australia is attributable solely to fragmentation of a former closed forest expanse. On the basis of an ecological survey of MVF patches concentrated on the western Arnhem Land region, but including observations over a wider region of the Northern Territory, it is shown that many MVF patches occur entirely on landforms developed only in the Holocene (i.e. the last 10 000 years) (e.g. coastal riverine floodplain alluvia, coastal beach ridge deposits). Indeed, 70% of the known Northern Territory MVF flora is observed to occur on such landforms. This paper also provides a review of relevant work undertaken on MVF in the Northern Territory at the time of writing, a description of MVF vegetation Habitat Types, an account of the dependent fauna, a checklist of the known flora, and an assessment of the conservation status of MVF in the region. The third paper, completed at the close of 22 months field studies, was prepared as a consultancy report to the Australian National Parks and Wildlife Service, Canberra. The report details the status, condition, and immediate threats to MVF ecosystems in the vicinity of Kakadu National Park, in the western Arnhem Land region. Special attention is given to the impacts of feral animals, and contemporary and traditional Aboriginal burning practices. The paper also considers the significance of MVF to traditional Aboriginal economy. The final two papers further develop certain themes outlined in preceding papers. The papers present formal analyses of ecological and biogeographical data, relating the findings to wi1der academic contexts. On the basis of studies concerning the distribution of MVF in the western Arnhem Land region, and the dispersal capacities and biogeographical affinities of component taxa, the fourth paper considers how these observations may contribute usefully to an understanding of the historical status of MVF in that region. The fifth paper is concerned essentially with the current status of MVF, drawing attention to the ecological ramifications of different burning regimes. To place fire in ecological context, this paper first explores the influence of substrate conditions on MVF distribution. These studies indicate that, in the absence of fire impact,seasonally xeric, oligotrophic substrates are unlikely to limit widespread development of closed canopy, MVF vegetation

Economic impacts of climate change on water resources in the coterminous United States

A national-scale simulation-optimization model was created to generate estimates of economic impacts associated with changes in water supply and demand as influenced by climate change. Water balances were modeled for the 99 assessment sub-regions, and are presented for 18 water resource regions in the United States. Benefit functions are developed for irrigated agriculture, municipal and domestic water use, commercial and industrial water use, and hydroelectric power generation. Environmental flows below minimal levels required for environmental needs are assessed a penalty. As a demonstration of concept for the model, future climate is projected using a climate model ensemble for two greenhouse gas (GHG) emissions scenarios: a business-as-usual (BAU) scenario in which no new GHG controls are implemented, and an exemplary mitigation policy (POL) scenario in which future GHG emissions are mitigated. Damages are projected to grow less during the 21st century under the POL scenario than the BAU scenario. The largest impacts from climate change are projected to be on non-consumptive uses (e.g., environmental flows and hydropower) and relatively lower-valued consumptive uses (e.g., agriculture), as water is reallocated during reduced water availability conditions to supply domestic, commercial, and industrial uses with higher marginal values. Lower GHG concentrations associated with a mitigation policy will result in a smaller rise in temperature and thus less extensive damage to some water resource uses. However, hydropower, environmental flow penalty, and agriculture were shown to be sensitive to the change in runoff as well.United States. Environmental Protection Agency. Office of Atmospheric Programs (Contract #EP-W-07-072

Deriving Multiple Benefits from Carbon Market-Based Savanna Fire Management: An Australian Example

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