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Ingham, Australia

Stanton P.,PO Box 154 | Stanton D.,719 Logan Road | Stott M.,GIS Section | Parsons M.,Recreation
Australian Forestry | Year: 2014

The vegetation and geology of the Wet Tropics Bioregion of North Queensland, covering 1 998 150 ha, were mapped at a scale of 1:50 000. The resulting geographic information system (GIS) data base provided an unprecedented opportunity to examine vegetation condition across the entire bioregion. Mapping used colour aerial photography at 1:25 000, informed by ground truthing. Vegetation type, nature of the understory and ground cover, degree and type of disturbance, and the presence of secondary vegetation were described by a coding system, with codes marked directly on the aerial photos.Analysis of these data has confirmed a picture, which emerged from ground truthing, of large areas of sclerophyll woodland and forest being invaded by a rainforest understory that prevents regeneration of the sclerophyll canopy. Fifty-three per cent of the native vegetation of the bioregion consists of non-rainforest vegetation types, dominated in both area and number by sclerophyll woodlands and forests. Seventeen per cent of the 735 713 ha of sclerophyll woodland and forest types were assessed as having suffered irreversible change. Between 25% and 79% of individual forest vegetation types were judged to have been affected by irreversible change. No climatic changes, or changes in the environment, apart from those related to changing fire regimes, were identified as causative factors. Changed fire regimes, predominantly fire exclusion, are considered to be the most likely cause. © 2014 Institute of Foresters of Australia (IFA). Source


Stanton P.,PO Box 154 | Parsons M.,Recreation | Stanton D.,719 Logan Road | Stott M.,GIS Section
Australian Forestry | Year: 2014

Meeting all four natural criteria for United Nations World Heritage listing, the Wet Tropics World Heritage Area that covers 61% of the remaining vegetation of the bioregion conserves, on a biodiversity basis, habitats containing threatened species of outstanding universal value from the point of view of science or conservation. As discussed in an accompanying paper by the same authors, the Wet Tropics Bioregion faces a level of habitat change unprecedented in threat and scale and manifested in the transition of sclerophyll forests and woodlands to closed forest habitats, a change attributable to the absence of fire or reduction in its frequency.The implications of habitat change for certain threatened species and ecosystems present a challenge to conserving the ark of biodiversity the Wet Tropics represents. Evidence indicates that the dominant reason for these changes in vegetation patterns is the reduction in fire or its exclusion across a bioregion with the highest rainfall of the nation. It is clear that the bioregion is suffering and with present trends, will continue to suffer, a major loss of habitat diversity. © 2014 Institute of Foresters of Australia (IFA). Source


Ngugi M.R.,Information Technology | Doley D.,University of Queensland | Botkin D.B.,University of Miami | Cant M.,Recreation | And 2 more authors.
Australian Forestry | Year: 2014

Estimates of carbon stocks and their annual change for extensive Australian sub-tropical forests are based on indirect estimates or on data derived from temperate forests. We estimated live above-ground tree carbon (LAC) stocks at landscape level from 355 000 measurements of 94 127 tree stems from 604 permanently monitored plots representing 2.6 million ha of managed uneven-aged mixed-species native forests in sub-tropical Queensland. These plots were established between 1936 and 1998 and re-measured every 2 to 10 years up to 2011. Landscapes were represented by 16 broad vegetation groups growing across a mean annual rainfall range of 500 to 2000 mm. Landscape-mean LAC stocks varied from 20.8 ± 4.3 t C ha-1 in inland eucalypt woodlands to 146.4 ± 11.1 t C ha-1 in coastal wet tall open forests. Landscape maximum LAC stock, defined as the mean of maximum LAC stocks over the entire measurement history for a specified landscape under prevailing environmental conditions and disturbance regimes, including sustainable forest management, ranged from 34.0 ± 7.2 t C ha-1 in inland eucalypt woodlands to 154.9 ± 19.4 t C ha-1 in coastal wet tall open forests. Annual live above-ground net carbon flux (C-flux) across all forests types ranged from 0.46 to 2.92 t C ha-1 y-1 with an overall mean of 0.95 t C ha-1 y-1 (n = 2067). Comparison of our results with Intergovernmental Panel on Climate Change (IPCC) estimates shows that in all cases, except for the sub-tropical steppe, the IPCC over-estimated stocks by between 13% and 34%. Conversely, the IPCC estimated C-fluxes were between 14% and 40% less than the Queensland estimates. These results extend statistically valid estimates of landscape LAC stocks and fluxes to the sub-tropical regions of Australia. © 2014 The State of Queensland. Source


Benfer D.,Queensland University of Technology | Baker A.M.,Queensland University of Technology | Ball T.,Recreation | Gynther I.,Threatened Species Unit | And 2 more authors.
Australian Journal of Zoology | Year: 2015

The water mouse, Xeromys myoides, is currently recognised as a vulnerable species in Australia, inhabiting a small number of distinct and isolated coastal regions of Queensland and the Northern Territory. An examination of the evolutionary history and contemporary influences shaping the genetic structure of this species is required to make informed conservation management decisions. Here, we report the first analysis undertaken on the phylogeography and population genetics of the water mouse across its mainland Australian distribution. Genetic diversity was assessed at two mitochondrial DNA (Cytochrome b, 1000bp; D-loop, 400bp) and eight microsatellite DNA loci. Very low genetic diversity was found, indicating that water mice underwent a recent expansion throughout their Australian range and constitute a single evolutionarily significant unit. Microsatellite analyses revealed that the highest genetic diversity was found in the Mackay region of central Queensland; population substructure was also identified, suggesting that local populations may be isolated in this region. Conversely, genetic diversity in the Coomera region of south-east Queensland was very low and the population in this region has experienced a significant genetic bottleneck. These results have significant implications for future management, particularly in terms of augmenting populations through translocations or reintroducing water mice in areas where they have gone extinct. © 2014 CSIRO. Source


Fletcher C.S.,CSIRO | Westcott D.A.,CSIRO | Murphy H.T.,CSIRO | Grice A.C.,CSIRO | Clarkson J.R.,Recreation
Journal of Applied Ecology | Year: 2015

Containment can be a viable strategy for managing invasive plants, but it is not always cheaper than eradication. In many cases, converting a failed eradication programme to a containment programme is not economically justified. Despite this, many contemporary invasive plant management strategies invoke containment as a fallback for failed eradication, often without detailing how containment would be implemented. We demonstrate a generalized analysis of the costs of eradication and containment, applicable to any plant invasion for which infestation size, dispersal distance, seed bank lifetime and the economic discount rate are specified. We estimate the costs of adapting eradication and containment in response to six types of breach and calculate under what conditions containment may provide a valid fallback to a breached eradication programme. We provide simple, general formulae and plots that can be applied to any invasion and show that containment will be cheaper than eradication only when the size of the occupied zone exceeds a multiple of the dispersal distance determined by seed bank longevity and the discount rate. Containment becomes proportionally cheaper than eradication for invaders with smaller dispersal distances, longer lived seed banks, or for larger discount rates. Both containment and eradication programmes are at risk of breach. Containment is less exposed to risk from reproduction in the 'occupied zone' and three types of breach that lead to a larger 'occupied zone', but more exposed to one type of breach that leads to a larger 'buffer zone'. For a well-specified eradication programme, only the three types of breach leading to reproduction in or just outside the buffer zone can justify falling back to containment, and only if the expected costs of eradication and containment were comparable before the breach. Synthesis and applications. Weed management plans must apply a consistent definition of containment and provide sufficient implementation detail to assess its feasibility. If the infestation extent, dispersal capacity, seed bank longevity and economic discount rate are specified, the general results presented here can be used to assess whether containment can outperform eradication, and under what conditions it would provide a valid fallback to a breached eradication programme. Weed management plans must apply a consistent definition of containment and provide sufficient implementation detail to assess its feasibility. If the infestation extent, dispersal capacity, seed bank longevity and economic discount rate are specified, the general results presented here can be used to assess whether containment can outperform eradication, and under what conditions it would provide a valid fallback to a breached eradication programme. © 2014 Commonwealth Scientific and Industrial Research Organisation. Source

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