Fire regimes of World Heritage Kakadu National Park., Australia

Abstract

LANDSAT Multi-Spectral Scanner imagery was used to determine aspects of the fire regimes of Kakadu National Park (in the wet-dry tropics of Australia) for the period 1980-1995. Three landscape types recognized in this Park were Plateau, Lowlands and Floodplain. Areas burned in early and late dry seasons each year were documented using a Geographical Information System. Regression analyses were used to examine time trends in the areas burned each year and the interrelationships between early and late dry season burning. The proportions of landscapes having different stand ages (years since fire), and the proportions having had different fire intervals, were compared with results expected from the simplest random model (i.e. one in which the probability of ignition at a point [PIP] burning annually was constant). Using overlays of successive stand-age maps, PIP could be calculated as a function of stand age. The Lowlands burned extensively each year; the areas burned by late dry season fires adding to those burned in the early dry season such that around 50-60% of the total area burned annually. Early dry season fires have lower intensities than late dry season fires, on average. Using a theoretically constant PIP and the mean proportion burned per year as the only input, predictions of areas burned as a function of stand age and fire interval were reasonable when compared with the empirical data, but best for the Lowlands landscape. PIP functions for Lowlands and Floodplains had negative slopes, an unexpected result. The nature of these PIP functions may reflect heterogeneity in fire proneness of the various vegetation types within landscapes. The scale of measurement, the scale of variation in vegetation types within a landscape, and the accuracy of the determination of burned areas, are constraints on the accuracy of fire-interval and seasonality determination perceived from an analysis of satellite data.

Environmental and allometric drivers of tree growth rates in a north Australian savanna

“…During the period 1980-1995, 50-60% of lowland savanna was burned each year, and 70% burned at least once every 2 years (Gill et al, 2000). Interestingly, there was a near 1:1 trade-off between burning in the early and in the late dry season, and an apparent shift to more, early season burning in the latter part of that period.…”

Editorial: Landscape and Seasonality—Seasonal Landscapes

“…98 -100, 127 -128); surprisingly, few systematic studies of the significance of seasonality for landscape in the Nordic countries have been carried out since (Jones, 2004). Elsewhere, there have been some studies on how people perceive the changes in landscape (see, for example, Higuchi, 1983;Porteous, 1990), and there have been studies of seasonal land cover using geographical information systems (GIS) and remote sensing techniques in different parts of the world (see, for example, Ferreira et al (2003) on Brazil; Gill et al (2000) on Australia; Loveland et al (1995) for the USA). However, four publications deserve special attention.…”

Potential role of ignition management in reducing unplanned burning in Arnhem Land, Australia

“…As Gill et al (2000) and found by analysing Landsat data, this treatment essentially works by 1:1 replacement of Late Dry Season fire with Early Dry Season fire, though in this study, the effect is slightly lower (slope −0.64 for Human Late Dry Season fires). This means that treatment does not reduce and may actually increase the overall area burnt, though account must be taken of the higher internal unburnt patchiness of Early Dry Season fires Oliveira et al 2015).…”

“…To date, the programme has been very effective, with a mean reduction in annual Late Dry Season burning from 32% to 11% per year by increasing Early Dry Season area burnt from 8% to 21% (Russell-Smith et al 2013). However, previous studies found that Early Dry Season treatment reduces Late Dry Season area burnt by a 1 to 1 replacement that suggests that Early Dry Season treatment on its own is only responsible for half of the achieved reduction in Late Dry Season burning (Gill et al 2000;. There are three possible reasons why WALFA may have been more successful than these studies predict.…”