Fire Management and Savanna Landscapes in Northern Australia

摘要

The vegetation cover of northern Australia ranges from open forest or woodland savanna (dominated by eucalypts over a range of highly flammable annual and perennial grasses) to hummock and tussock grasslands occupying sandy and fertile fine-textured soils. Like monsoonal eastern Indonesia, the major fire period occurs over the long dry season, typically between April/May-October/November. People light fires for a range of land management purposes; lightning strikes cause relatively few fires at the start of the annual wet season. Based on regional mapping of fires from satellite imagery (mostly NOAA-AVHRR and LANDSAT) from the 1980s, we can identify two broad patterns concerning the application of fire in nrothern Australia. In northwestern and northern Australia, and possibly also on parts of Cape York in the northeast, intense wild fires typically late in the dry season burn vast tracts annually. Ecological studies indicate that such fire regimes are having catastrophic impacts on native fire-sensitive species, communities, and habitats. Conversely, elsewhere across northern Australia but especially on more productive pastoral lands, the restricted application/absence of burning is in some cases leading to native and exotic woody species thickening/invading, likewise with profound ecologic and economic consequences. Growing recognition of these issues has led to the development of collaborative fire managmeent programs in various parts of northern Australia. Similar cooperative approaches involving practitioners from northern Australia working with relevant parties in eastern Indonesia and Papua New Guinea would bring significant benefit to the study of regional landscape management issues.