Aim We test the hypothesis that the European destruction of western Tasmanian Aboriginal society, and consequent changes in burning patterns, resulted in succession towards rain forest near the coast, and an increase in the area of more fire‐resistant sedgeland in inland areas. Location South‐western and western Tasmania, Australia. Methods Attributes of organic soils (surface and underlying dominant horizons) beneath rain forest and sedgeland were described and measured from 559 soil pits in areas with highly siliceous surface geology. Multiple logistic regression was used to discriminate the dominant horizons of rain forest and sedgeland soils. This equation was used to derive scores for all soil pits. The hypothesis that change was greater near existing boundaries was tested using correlation. The hypothesis that change was greater at coastal than inland locations was tested using ANOVA. Results Both upper horizons of the soils under the fire‐sensitive rain forest (14C‐dated to be younger than 60 years) and dominant horizons of these soils had significantly higher organic contents, lower bulk density and more nitrogen than the soils under the fire‐requiring sedgeland. Twenty‐nine per cent of the soils under sedgeland had dominant horizons that indicated past rain forest. One‐quarter of the soils under rain forest had dominant horizons characteristic of sedgeland soils. Although results were heterogeneous in both locations, the former difference was more common inland and the latter near the coast. Change was not higher close to present boundaries. Main conclusions The characteristics of the dominant horizons and the post‐colonial surface horizon give a strong indication of the vegetation that formed them. Changes in fire regimes, caused by the displacement of Tasmanian Aborigines by Europeans, appear to have caused vegetation changes that differed within and between the coast and inland areas. Thus, there has been a strong human role in determining the distributions of vegetation types in the region.
1. We investigated the characteristics and causes of striped patterning in minerotrophic Sphagnum cristatum mires on the western Central Plateau in Tasmania by surveying the mire vegetation, surface and subsurface topography, analysing their topographic exposure to the prevailing strong winds relative to non-striped mires, stratigraphic analysis, measurements of wind speed and direction across and along ridges and swales in typical synoptic conditions, and measurement of growth rates and asymmetry of shrubs. 2. The stripes were orientated south-west-north-east, independent of the aspect of the general slope. The shrub Richea scoparia was dominant on the north-west-facing slopes of the low ridges that formed the stripes. Sphagnum cristatum was dominant on the south-east-facing ridge slopes and the restiad, Baloskion australe was dominant in the swales. The stripes were independent of the topography of the underlying block stream. Striped mires were more exposed to both north-westerly and south-westerly winds than non-striped mires. 3. Strong north-westerly winds formed rotors behind each ridge, with wind speed being highest on the north-west-facing ridge slope and lowest on the south-east-facing ridge slope. The annual growth of R. scoparia inversely reflected this variation in wind speed. South-westerly winds were stronger in the swales than on the ridges and stronger on the south-west extremity of the ridges than further to the north-east. Asymmetry in R. scoparia on the ridges reflected this variation in wind speed. 4. We infer that the ridges slowly migrate in a cyclic successional pattern as the result of differential growth rates of R. scoparia in response to variation in the speed of drying north-westerly winds. The stripes appear to result from training of shrubs by strong, cold south-westerly winds, which also inhibit the growth of R. scoparia in the swales. 5. Synthesis. There are no other documented cases of wind-controlled patterning and cyclic succession in mires, and no case of exposure to two distinct wind directions being responsible for patterning in any vegetation type. The distinctiveness of the process and the form merit recognition of these striped mires as outstanding in their universal value under the world heritage area criteria.
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