39 resultados para flooded forests

em Deakin Research Online - Australia


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The Beautiful Firetail (Stagonopleura bella) is an uncommon, granivorous finch from coastal south-eastern Australia, with a distribution extending from mid-coastal New South Wales to south-eastern South Australia, including Tasmania. This paper presents a quantitative assessment of habitat use by the Beautiful Firetail based on data collected from 30 paired riparian and non-riparian sites in the foothill forests of the Victorian Highlands, Australia. The Beautiful Firetail occurred in two of the three forest blocks surveyed and was found almost exclusively at riparian sites. The Beautiful Firetail was most likely to occur at riparian sites on the coastal fall of the ranges at sites with high sedge cover and low cover of shrubs and bare ground. The species occurred at low densities (0.10–0.19 individuals ha–1) throughout the year. Records from the Atlas of Victorian Wildlife were used to describe the distribution of Beautiful Firetails in Victoria. Notable observations inland of the Great Dividing Range were recorded during the present study. Further study is required to understand the ecological requirements of the Beautiful Firetail throughout its range.


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Australia's box-ironbark forests and woodlands once covered about 14 per cent of the State of Victoria on the riverine plains and foothills of the Great Dividing Range. But approximately 83 per cent of the total original habitat has been destroyed and what remains of this significant ecosystem is now highly fragmented and vulnerable to further degradation. Moreover, only 14 per cent of the area remaining is on public land. A 10 year campaign on the part of the environmental movement eventually succeeded in forcing the State government to conduct an independent inquiry into this ecosystem and make recommendations on future management. This paper outlines the innovative public participation process adopted by the Victorian State government and the outcomes of the inquiry. A subsequent compensation package for commercial operations disadvantaged by the proclamation of a series of new national parks is also discussed, as are the shortcomings of a process that can have little or no impact on what happens on private land.

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The depletion and reservation levels of wetlands varied significantly both across the Murray Fans and Victorian Riverina bioregions and in the study area of the Victorian Environmental Assessments Council's River Red Gum Forests Investigation. The proportion of Freshwater Meadows in protected areas was substantially lower than for other wetland types. Furthermore, of the wetlands that are reserved, many were only partially within a protected area. A variety of reserve categories are used to protect wetlands across the three regions, ranging from reserves with high legal protection and a strong focus on biodiversity conservation to reserves with a lower level of protection and emphasis on biodiversity
conservation. The findings highlight that many wetlands are incompletely reserved in Victoria's northern plains and riverine forests. The current review of public land use in the River Red Gum Forests, which includes Barmah Forest, should recognise these issues to ensure the effective reservation of wetland ecosystems.

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Tracheophyte and bryophyte distribution was surveyed in nineteen Blackwood-dominated sites of two different origins in the Otway Ranges. Nine sites were placed in sheltered gullies and ten sites were placed in upslope stands. Fifty-one tracheophyte taxa, 49 moss taxa and 39 liverwort (including hornwort) taxa were recorded in total. Bryophyte species richness was significantly higher in gully sites. The most frequent bryophyte taxa varied between gully and upslope sites. The percentage
occurrence of certain substrates was shown to be an important determinant of bryophyte species richness and composition. Decaying wood and soil supported the greatest number of bryophyte taxa compared with all other substrates.

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In order to plan for the best use of public land at a regional scale the determination of an appropriate regional boundary is important for ecological, resource use and recreational reasons. The study area for the Victorian Environmental Assessment Council's (VEAC) River Red Gum Forests Investigation incorporated bioregional boundaries, modelled pre- I750 vegetation distribution, recent public land use investigations, and the distribution of public land. This paper outlines how ecological attributes and past land use studies were used to inform the boundary for this major study of public land along the Murray River in northern Victoria.

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Health is inherently 'ecological' and the natural environment plays a crucial role in human health and well-being. Yet we do not necessarily design, manage or market such areas in ways that acknowledge this link. This paper draws on recent research by a Deakin University team exploring the links between use of and involvement in the maintenance of forests/woodlands, and health and well-being outcomes. Qualitative and quantitative methods have been used to collect data from forest/woodland users and tram volunteers contributing to management and maintenance of such areas, concerning their perceptions of the impacts of the experience
on their health and well-being. In two of the projects, samples of 'users' and 'volunteers' were compared with samples 'non-users' and 'non-volunteers'. Several of the studies included the use of scales of self-rated health, social cohesion, and frequency of use of medical services.The studies have identified a range of perceived physical, mental and social health benefits resulting from use of and/or engagement with forests/woodlands. Study findings have implications for design, management and marketing of such areas, since they identity factors influencing use of and engagement with such areas, and have the potential to promote more widespread recognition of the value of such areas and more commitment to them by individuals, communities and governments. The challenge for us is to build on this research base to more clearly Signpost the mutually beneficial links between forest and woodland ecosystems and human health and well-being, creating new and better pathways to a healthy future.

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Land use change has occurred rapidly in southwestern Victoria over the last decade and is expected to continue, albeit at a slower pace. One of these changes has been the development of 'new forests', that is industrial and farm forestry plantations and environmental plantings. Some of the challenges that these land use changes pose for water and natural resource managers are discussed. Land use change is expected to substantially reduce potential water yield in four of the region's seven drainage basins (A).

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The blackwater model was developed to predict adverse water quality associated with flooding of the Barmah-Millewa Forests on the River Murray. Specifically, the model examines the likelihood and severity of blackwater events—high dissolved organic carbon associated with low dissolved oxygen. The Barmah-Millewa Forests are dominated by an overstorey of River Red Gum (Eucalyptus camaldulensis) and the litter from these trees contributes a substantial proportion of the pulse of dissolved organic matter released from the floodplain during flooding. This model examines rates of litter accumulation and decay on the floodplain (prior to and during flooding), rates of carbon leaching, microbial degradation, oxygen consumption, reaeration processes and the effects of flow on the concentrations of dissolved organic carbon and dissolved oxygen in the water column (both on the floodplain and in the river channel downstream). The model has been calibrated with data from two blackwater events that have taken place in these forests within the last 5 years. Scenario testing with the model highlights the particularly important roles of flow and temperature in the development of anoxia. Pooled floods and those in the warmest months of the year are substantially more likely to result in blackwater events than floods in cooler times of the year and involving more water exchange between the river channel and the floodplain.

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Nestedness in biota as a function of species richness – biota of depauperate assemblages being non-random subsets of richer biotas – has been widely documented in recent years (see Wright et al. 1998, Oecologia 113: 1–20). Ordering sites by richness maximizes nestedness indices; however, ordering by other criteria such as area or isolation may be more ecologically interpretable. We surveyed birds in true fragments (35 in all), and in "reference areas" in large extant forest blocks (30 locations), of the same range of areas (10, 20, 40, 80 ha). The avifauna was divided into "bush birds"– species dependent on forest and woodland, and "open country" species. We looked at nestedness in four data sets: "bush birds" in fragments and reference areas, and "all birds" in fragments and in reference areas. All data sets were significantly nested. Ordering by area in all cases was not significantly less nested than ordering by richness. Ordering by area in fragments was significantly greater than in reference areas, but the differences in standardized nestedness indices were small (<15%). We identified those birds that had distributions among fragments that conformed strongly with area, those that were more randomly distributed and some species that were more likely to occupy the smallest fragments. Among the latter was a hyperaggressive, invasive, colonial native species (noisy miner Manorina melanocephala). A suite of small, insectivorous birds were more likely to strongly conform with expected distributions in relation to area, which was consistent with observations of their vulnerability to the effects of the noisy miner in smaller fragments.

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SWAT cannot accurately simulate the seasonal fluctuations or the long-term trend of the Leaf Area Index (LAI) of evergreen forests. This deficiency has detrimental impacts for the prediction of interception and transpiration, two processes that have a significant influence on catchment water yield. This paper details the integration of the forest growth model 3-PG with SWAT to improve the simulation of LAI for evergreen forests. The integrated model, called SWAT/3-PG, was applied to the Woady Yaloak River Catchment in southern Australia where eucalyptus forests and pine plantations account for 30% of the total land use. SWAT/3-PG simulated the LAI of eucalypts and pines more accurately and realistically than the original version of SWAT. Forest LAI simulated by SWAT/3-PG agreed reasonably well with estimates of forest LAI derived independently from a Landsat satellite image. SWAT/3- PG has considerable value as a tool that managers can utilise to predict the impacts of land use change in catchments where evergreen forests are prevalent.

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Shallow water habitats within estuarine systems are believed to be important areas for small fish. While a wide variety of shallow habitats have been studied, the land that becomes inundated by the damming effect after the closure of intermittently open mouths has previously been overlooked. Fish were sampled monthly from both the main channel and flood zone of an intermittently open estuary between July 2004 and June 2005 using minifyke nets during the day and at night. A total of 7,787 fish were collected during the study representing 13 species and 11 families. Philypnodon grandiceps was the most abundant species and, together with Atherinosoma microstoma, Pseudogobius olorum, and Galaxias maculatus, made up 94% of the total catch. Inundation of the flood zone occurred in two discrete forms associated with mouth condition, which consisted of sporadic flooding while the mouth was open, to long-term flooding for 6 months after its closure. Large numbers of fish were captured on the flood zone, which included nine species; however, A. microstoma dominated the catch. A distinct shift in the flood zone fish assemblage occurred between the two mouth conditions, which is likely associated with changes in hydro-period and food availability of the flood zone and physico-chemical parameters in the main channel. There was no longitudinal variation in the fish assemblage in both the main channel and flood zone; similarly, the diel period was found to have little effect on the fish assemblage. The total catch per unit effort did not vary across seasons and suggests that fish abundance within the estuary is stable throughout the year. Unlike other estuarine systems where shallow water fish assemblages may be structured by variations in tide and elevation within the Surrey, freshwater inflow and, more importantly, mouth condition appear to have the greatest influence in composition of the shallow water flood zone fish assemblage of intermittently open estuaries.

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