Richard Thackway

Bushfires 'down under': patterns and implications of contemporary Australian landscape burning

Australia is among the most fire-prone of continents. While national fire management policy is focused on irregular and comparatively smaller fires in densely settled southern Australia, this comprehensive assessment of continental-scale fire patterning (1997-2005) derived from ∼ 1k m 2 AdvancedVery High Resolution Radiometer (AVHRR) imagery shows that fire activity occurs predominantly in the savanna landscapes of monsoonal northern Australia. Sta- tistical models that relate the distribution of large fires to a variety of biophysical variables show that, at the continental scale, rainfall seasonality substantially explains fire patterning. Modelling results, together with data concerning seasonal lightning incidence, implicate the importance of anthropogenic ignition sources, especially in the northern wet-dry tropics and arid Australia, for a substantial component of recurrent fire extent. Contemporary patterns differ markedly from those under Aboriginal occupancy, are causing significant impacts on biodiversity, and, under current patterns of human popula- tion distribution, land use, national policy and climate change scenarios, are likely to prevail, if not intensify, for decades to come. Implications of greenhouse gas emissions from savanna burning, especially seasonal emissions of CO2, are poorly understood and contribute to important underestimation of the significance of savanna emissions both in Australian and probably in international greenhouse gas inventories. A significant challenge for Australia is to address annual fire extent in fire-prone Australian savannas.

Describing and mapping human-induced vegetation change in the Australian landscape

Australian reporting requirements for native vegetation require improved spatial and temporal information on the anthropogenic effects on vegetation. This includes better linkage of information on vegetation type (e.g., native vegetation association), extent and change, vegetation condition, or modification. The Vegetation Assets, States and Transitions (VAST) framework is presented as a means for ordering vegetation by degree of anthropogenic modification as a series of condition states, from a residual or base-line condition through to total removal. The VAST framework facilitates mapping and accounting for change and trends in the status and condition of vegetation. The framework makes clear the links between land management and vegetation condition states, provides a mechanism for describing the consequences of land management practices on vegetation condition, and contributes to an understanding of resilience. VAST is a simple communication and reporting tool designed to assist in describing and accounting for anthropogenic modification of vegetation. A benchmark is identified for each vegetation association. Benchmarks are based on structure, composition, and current regenerative capacity. This article describes the application of the VAST framework as a consistent national framework to translate and compile existing mapped information on the modification of native vegetation. We discuss the correspondence between these compiled VAST datasets at national and regional scales and describe their relevance for natural resource policy and planning.

Responding to Change — Criteria and Indicators for Managing the Transformation of Vegetated Landscapes to Maintain or Restore Ecosystem Diversity

European settlement, beginning only towards the end of the 18th century, brought the introduction of pastoralism and cropping to landscapes where the previous human impact had mainly been the use of fire to assist hunting [3]. Various studies with a focus on the loss of species suggest that, since European settlement in the late 18th Century, Australia has had the world’s highest rate of extinctions of mammalian fauna and parallel losses of biodiversity across many of its ecosystems [4, 5].

Monitoring Status and Condition of Australian Mediterranean-Type Forest Ecosystems

Mediterranean-type ecosystems are found across southern Australia. Climate, topography and soils in these regions are similar to those in southern Europe and therefore suitable for the cultivation of European crops and the husbandry of animals. Consequently, significant areas of forested Mediterranean-type ecosystems have been cleared for agriculture. The status of forested Mediterranean-type ecosystems is presented using data and information in the National Vegetation Information System (NVIS). Remaining Mediterranean-type forests are used for timber production and provide a wide range of other services such as biodiversity conservation, water quality and recreational opportunities. Monitoring of the status and condition of these forests plays an essential role in understanding the environmental, social and economic consequences of land use changes upon these ecosystems. The National Forest Inventory (NFI) acts as a national coordinating body for data collection, integration, analysis and reporting on Australian forests. Two case studies illustrate the considerable expansion of forest plantations and the ongoing need to improve systems for monitoring these forests at local, regional and national levels. Current approaches to monitoring of a range of forest ecosystem values under the NFI and NVIS frameworks are discussed.