Giant eucalypts - globally unique fire-adapted rain-forest trees?

Tree species exceeding 70 m in height are rare globally. Giant gymnosperms are concentrated near the Pacific coast of the USA, while the tallest angiosperms are eucalypts (Eucalyptus spp.) in southern and eastern Australia. Giant eucalypts co-occur with rain-forest trees in eastern Australia, creating unique vegetation communities comprising fire-dependent trees above fire-intolerant rain-forest. However, giant eucalypts can also tower over shrubby understoreys (e.g. in Western Australia). The local abundance of giant eucalypts is controlled by interactions between fire activity and landscape setting. Giant eucalypts have features that increase flammability (e.g. oil-rich foliage and open crowns) relative to other rain-forest trees but it is debatable if these features are adaptations. Probable drivers of eucalypt gigantism are intense intra-specific competition following severe fires, and inter-specific competition among adult trees. However, we suggest that this was made possible by a general capacity of eucalypts for 'hyper-emergence'. We argue that, because giant eucalypts occur in rain-forest climates and share traits with rain-forest pioneers, they should be regarded as long-lived rain-forest pioneers, albeit with a particular dependence on fire for regeneration. These unique ecosystems are of high conservation value, following substantial clearing and logging over 150 yr. Contents Summary 1001 I. Introduction 1001 II. Giant eucalypts in a global context 1002 III. Giant eucalypts - taxonomy and distribution 1004 IV. Growth of giant eucalypts 1006 V. Fire and regeneration of giant eucalypts 1008 VI. Are giant eucalypts different from other rain-forest trees? 1009 VII. Conclusions 1010 Acknowledgements 1011 References 1011.

Healthy country: healthy people? Exploring the health benefits of indigenous natural resource management.

OBJECTIVE: Decades of health-related research have produced a large body of knowledge describing alarming rates of morbidity, mortality and social/cultural disruption among Indigenous Australians, but have failed to deliver sustainable interventions to arrest the deepening spiral of ill-health. This paper explores the potential of Indigenous natural resource management (NRM) activities to promote and preserve Indigenous health in remote areas of northern Australia. METHOD: A literature review of the health, social science and ecology peer-reviewed journals and secondary literature. CONCLUSIONS AND IMPLICATIONS: Effective interventions in Indigenous health will require trans-disciplinary, holistic approaches that explicitly incorporate Indigenous health beliefs and engage with the social and cultural drivers of health. Aboriginal peoples maintain a strong belief that continued association with and caring for ancestral lands is a key determinant of health. Individual engagement with 'country' provides opportunities for physical activity and improved diet as well as boosting individual autonomy and self-esteem. Internationally, such culturally congruent health promotion activities have been successful in programs targeting substance abuse and chronic diseases. NRM is fundamental to the maintenance of biodiversity of northern Australia. Increased support for Indigenous involvement in land and sea NRM programs would also deliver concrete social benefits for communities including opportunities for sustainable and culturally apt regional employment, applied education and economic development. NRM may also reinvigorate societal/cultural constructs, increasing collective esteem and social cohesion.

The impact of Aboriginal landscape burning on the Australian biota.

One of the most complex and contentious issues in Australian ecology concerns the environmental impact of Aboriginal landscape burning. This issue is not only important for the development of a comprehensive understanding of the dynamics and evolution of the Australian biota, but is central to the formulation of appropriate strategies for the conservation of the nation's biodiversity. Ethnographic evidence leaves little doubt that Aboriginal burning played a central role in the maintenance of the landscapes subsequently colonized by Europeans. Both 19th century European colonists and anthropologists in the 20th century documented the indispensability of fire as a tool in traditional Aboriginal economies, which have aptly been described as 'fire-stick farming'. Aborigines used fire to achieve short-term outcomes such as providing favourable habitats for herbivores or increasing the local abundance of food plants, but it is not clear whether or not Aborigines had a predictive ecological knowledge of the long-term consequences of their use of fire. A large body of ecological evidence suggests that Aboriginal burning resulted in substantial changes in the geographic range and demographic structure of many vegetation types. Aboriginal burning was important in creating habitat mosaics that favoured the abundance of some mammal species and in the maintenance of infrequently burnt habitats upon which the survival of specialized fauna depends. Aboriginal fire regimes were probably critical for the maintenance of at least one species of tree (Callitris intratropica) in the monsoon tropics. The question of the original impact of humans on the Australian environment is fundamentally speculative because of vague, disputed time frames proposed for the waves of colonization and shifting settlement patterns of Aborigines in the late Quaternary period. There is an inherent circular argument concerning the cause and effect of climate change, vegetation change, and burning through the late Quaternary. Charcoal and pollen evidence from long sedimentary cores is ambiguous and cannot be used to demonstrate unequivocally the initial impact of Aboriginal people on the landscapes of Pleistocene Australia. The sparse available evidence does not support the hypotheses that Aboriginal burning was primarily responsible for the extinction of Pleistocene megafauna; was critical for the maintenance of habitats of small mammals that have become extinct following European colonization; initiated widespread accelerated soil erosion rates in either the Pleistocene or Holocene; or forced the evolutionary diversification of the Australian biota. Burning may have caused the extinction of some fire-sensitive species of plants and animals dependent upon infrequently burnt habitats, and it must have maintained structurally open vegetation such as grasslands and also extended the range of fire-adapted species, such as Eucalyptus, into environments climatically suitable for rain forest. Palaeoecological research concerning prior impacts of Aborigines must give way to focused studies of the role of different anthropogenic fire regimes in contemporary ecosystems that have not been destroyed by European colonization. Such research is crucial for comprehending the role of Aboriginal burning in the maintenance of Australia's unique, rich biodiversity. CONTENTS Summary 385 I. Introduction 386 II. Aborigines and fire 386 III. Ecological perspectives 390 IV. Palaeoecological perspectives 394 V. General conclusions 404 Acknowledgements 405 References 405.