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A long-term study of a bolster heath–pond system at Newdegate Pass, Mount Field, Tasmania, was designed to test a theory of cyclical dynamics and to determine why there was constancy in the proportions of species in stable mosaic bolster heath, while their individual distributions changed. Groups of permanent plots were monitored approximately once every 5 years between 1983 and 2017, in apparently stable, apparently colonising, apparently recovering and apparently degrading bolster heath. The putatively stable sites exhibited an average of 37% spatial turnover in the three early 5-year periods, with reciprocal replacements between many pairs of species; however, there was little evidence of long-term directional change except for expansion of a gymnosperm shrub across the top of the bolster mosaic at one site. This pattern suggests a cyclical succession of species in the stable mosaic; however, the mechanism driving cyclicity remains unclear, with facilitation, competition and stochastic processes being implicated at different times and locations. These cyclic changes were likely to have been largely endogenous, given the variability and autocorrelations in relative growth rates of the stable mosaic over short horizontal distances, conforming with neutral theory. The process of dam vegetation loss after draining was rapid, as was vegetation colonisation of the floor of one dam and recovery from fire. On a putatively colonising site on rocky ground, changes were subdued but directionally consistent with the previously proposed model, which was consistent with all long-term observations. The dynamics of a pond and mosaic bolster heath complex monitored for 35 years conformed to a posited cyclic pattern of organic dam growth, organic dam draining, dam dissolution and recolonisation of the dam floor. The stable mosaic bolster heaths between the ponds constantly changed patterns of species distribution while maintaining the same proportionate cover of individual species, a phenomenon most consistent with the stochastics of neutral theory. [ABSTRACT FROM AUTHOR]

A decline was observed in the subantarctic Macquarie Island endemic cushion, Azorella macquariensis, during the summer of 2008-2009, resulting in the listing of the species as critically endangered in 2010. Photographs of A. macquariensis in the period 2009-2013 were used to (1) identify types of damage, (2) determine the likely causes of three distinct types of damage, (3) establish whether dieback was spreading from affected to unaffected sites and (4) find out whether dieback was associated with the expansion of Agrostis magellanica. Grey damage occurred on the most wind-exposed parts of cushions and on the most wind-exposed sites. Speck damage occurred in the opposite situations and was consistent in its location, attributes and timing with rabbit grazing. Yellow dieback was sporadic in its occurrence. Its symptoms were consistent with those of a pathogen. Yellow damage expanded between spring 2009 and autumn 2010, with neither grey nor speck damage increasing. Yellow damage was associated with a marked decline in live cushion cover in plots between 2010 and 2013. The cushion was not eliminated from any plots, despite increased cover of A. magellanica in plots with dead cushions. Only one site not affected by yellow damage in 2010 had become affected by 2013. Given these results, and given that yellow damage has been observed in the past, 2008-2010 may have been an infrequent extreme outbreak of a pathogen and/or a response of a pathogen to ongoing climatic change. Dieback in the cushion Azorella macquariensis, on Macquarie Island was monitored for four years. Although damage from wind appeared responsible for most damage at any one time, a yellow dieback, with symptoms consistent with a pathogen, caused the most rapid dieback. [ABSTRACT FROM AUTHOR]

Historical landscape paintings are widely used to reconstruct past environments. However, artists did not necessarily fully depict reality, many exercising license to relocate and remould features. This paper applies photogrammetric techniques to the problem of determining the accuracy of artistic depictions of landscapes. Four 19th century paintings of Hobart, Tasmania, Australia by different artists were used to test the methods. The artists varied in their accuracy, with Frankland, the surveyor, being the most accurate, and Glover, the romantic professional artist, being the least accurate. This variation suggests that the use of paintings for historical reconstructions and measurements of historic features should be preceded by an accuracy assessment. [ABSTRACT FROM AUTHOR]

The regeneration of plants post-fire has widely been shown to be attractive to vertebrate herbivores. However, there are few data relevant to the effect of fire size on herbivore densities. In dry eucalypt forest in one region and hummock sedgeland in another region, we used timed scat counts to test the effect of fire and fire size on Tasmanian macropod densities 6 months after burning. We also tested whether soil characteristics and the nature of ground cover related to the degree of attractiveness of post-burn regeneration. Soil nutrients and higher covers of grasses and herbs in ground layer vegetation were associated with higher macropod densities. In dry eucalypt forest, fire incidence and fire size did not affect macropod density, while in hummock sedgeland, fire had a positive effect on macropod density, but fire size had no effect. [ABSTRACT FROM AUTHOR]

Is the 'Big Australia' vision of a populous, prosperous Australian nation in 2050 compatible with the maintenance of productive soils and/or the maintenance of native species? This paper considers the implications of current tendencies in soil and species conservation and suggests some ways to avoid the more negative of them. Current land use in Australia is mining the soils on slopes. It seems likely that deposits of rock phosphate will be close to depletion by 2050, making fertilisers that are essential for industrial agriculture very expensive. Petroleum, which is converted into most of the food traded globally, seems also likely to be near depletion and expensive. The prospective substitution of coal for oil promises interesting changes to the global earth-atmosphere system. Nevertheless, under an optimistic business as usual scenario, Australia probably could feed 36 million people in 2050, but not necessarily for very much longer. Thus, a 'Big Australia' in 2050 could be a way station on the road to a human population crash. The conservation of Australian native species has been hindered by frequent changes in all of funding, bureaucratic structure and scientific dogma. The political and social processes that support a growth economy encourage such short term thinking. A transition to long term thinking will be necessary if support systems for humans and other species are to be maintained. [ABSTRACT FROM AUTHOR]

Vertebrate grazers have been shown to be a critical element in maintaining lawns, although lawns can also form in places without such herbivores. In Tasmania lawns are widespread in lentic wetlands. We used environmental observations and exclosure experiments at two altitudinally contrasting lentic wetland lawns, and waterlogging experiments, to test the hypotheses that their structure is maintained (i) periodic inundation; and (ii) grazing. Waterlogging experiments and field observations demonstrated that the two main invading shrubs were indifferent to immersion for several months and that the distribution of the lawns was independent of inundation period, results inconsistent with the first hypothesis. The exclosure experiments showed that both woody and non-woody plants became taller in the lawns when marsupial grazers and rabbits were excluded. It therefore seems that the lawn structure is maintained by grazing and that alternative structural states result from exclusion of grazing pressure in less than 2 years. [ABSTRACT FROM AUTHOR]

Boneseed, Chrysanthemoides monilifera ssp. monilifera (Asteraceae) is concentrated in and near cities and towns on the north and east coasts of Tasmania. Its absence from intervening rural and bushland areas cannot be attributed to environmental conditions or a lack of time for dispersal from introduction points. The hypothesis tested in the present paper is that the range of boneseed in Tasmania is limited by biotic resistance through herbivory. Cafeteria experiments and field observations showed that sheep ( Ovis aries), cattle ( Bos taurus), Tasmanian pademelons ( Thylogale billardierii), Bennett's wallabies ( Macropus rufogriseus), garden weevils ( Phlyctinus callosus) and native invertebrates all consumed boneseed, while common brushtail possums ( Trichosurus vulpecula) did not. A boneseed population subjected to sheep grazing for 168 days suffered high mortality, while an adjacent ungrazed population survived intact. A replicated exclosure experiment showed that 75 days of grazing by cattle reduced the size of boneseed plants. Observations of a population subject to Bennett's wallaby and Tasmanian pademelon grazing over 1 year and 2 months showed consistently high leaf damage to foliage within pademelon reach and a decline in population, with high mortality rates in the driest and coldest times. Leaf loss attributable to invertebrates did not prevent a nearby population without wallabies from growing. The distributions of the taxa were consistent with biotic resistance, with those demonstrating no severe effect on boneseed individuals widespread, while those with evidence of severe effects more common in rural areas than in urban areas. Boneseed seemed unlikely to survive for very long at normal stocking levels. Macropod grazing, particularly that of T. billardierii, may also inhibit the invasion of boneseed. Thus, the recent introduction of foxes to Tasmania may not only cause the extinction of species such as T. billardierii, but also may cause an expansion of the range of boneseed. [ABSTRACT FROM AUTHOR]

The disciplinary space that geographers conceive to be theirs has all been previously possessed, or latterly colonised, by other disciplines. Geographers defend their existence on the basis of their oft-asserted, but never tested, cross-disciplinarity. The journals in which refereed papers were published by members of the Institute of Australian Geographers (IAG) and the papers in Australian Geographical Studies were analysed for the period 1998–2002 to test the hypothesis of cross-disciplinarity in both subject and method. IAG members do strongly tend to publish in more than one disciplinary area, and a large proportion of papers in Australian Geographical Studies are integrative across subdisciplines in geography, with many using more than one methodological approach. However, transgression of the physical geography/human geography divide was sufficiently uncommon to create a statistical break between sets of subdisciplines. Based on the data used in the present paper, Australian geographers can make a case for being members of a vital, integrative discipline, likely to make substantial advances in the hybrid spaces. [ABSTRACT FROM AUTHOR]