Estimates of Heterozostera tasmanica, Zostera muelleri and Ruppia megacarpa distribution and biomass in the Hopkins Estuary, western Victoria, by GIS

Knowledge of the spatial arrangement of the seagrass distribution and biomass within the Hopkins Estuary is an essential step towards gaining an understanding of the functioning of the estuarine ecosystem. This study marks the first attempt to map seagrass distribution and model seagrass biomass and epiphyte biomass along depth gradients by the use of global positioning system (GPS) and geographical information system (GIS) technologies in the estuary. For mapping seagrass in small estuaries, ground-surveying the entire system is feasible. Three species of seagrasses, Heterozostera tasmanica (Martens ex Aschers), Zostera muelleri (Irmisch ex Aschers) and Ruppia megacarpa (Mason), were identified in the Hopkins Estuary. All beds investigated contained a mixed species relationship. Three harvest techniques were trialed in a pilot study, with the 25 × 25-cm quadrat statistically most appropriate. Biomass of seagrasses and epiphytes was found to vary significantly with depth, but not between sites. The average estimate of biomass for total seagrasses and their epiphytes in the estuary in January 2000 was 222.7 g m^–2 (dry weight). Of the total biomass, 50.6% or 112.7 g m^–2 (dry weight) was contributed by seagrasses and 49.4% of the biomass (110.0 g m^–2) were epiphytes. Of the 50.6% of the total biomass represented by seagrasses, 39.3% (87.5 g m^–2) were leaves and 11.3% (25.2 g m^–2) were rhizomes. The total area of seagrasses present in the Hopkins Estuary was estimated to be 0.4 ± 0.005 km², with the total area of the estuary estimated to be 1.6 ± 0.02 km² (25% cover). The total standing crop of seagrasses and epiphytes in the Hopkins Estuary in January 2000 was estimated to be 102.3 ± 57 t in dry weight, 56% (56.9 ± 17 t, dry weight) seagrasses and 44% (45.4 ± 19 t, dry weight) epiphytes. Of the seagrass biomass, 39% (39.7 ± 13 t, dry weight) was contributed by leaves and 17% (17.3 ± 7 t, dry weight) by rhizomes.

Predicting the distribution of discrete spatial events using artificial neural networks

Although the development of geographic information system (GIS) technology and digital data manipulation techniques has enabled practitioners in the geographical and geophysical sciences to make more efficient use of resource information, many of the methods used in forming spatial prediction models are still inherently based on traditional techniques of map stacking in which layers of data are combined under the guidance of a theoretical domain model. This paper describes a data-driven approach by which Artificial Neural Networks (ANNs) can be trained to represent a function characterising the probability that an instance of a discrete event, such as the presence of a mineral deposit or the sighting of an endangered animal species, will occur over some grid element of the spatial area under consideration. A case study describes the application of the technique to the task of mineral prospectivity mapping in the Castlemaine region of Victoria using a range of geological, geophysical and geochemical input variables. Comparison of the maps produced using neural networks with maps produced using a density estimation-based technique demonstrates that the maps can reliably be interpreted as representing probabilities. However, while the neural network model and the density estimation-based model yield similar results under an appropriate choice of values for the respective parameters, the neural network approach has several advantages, especially in high dimensional input spaces.

Distribution of an alien aquatic snail in relation to flow variability, human activities and water quality

1. Disturbance and anthropogenic land use changes are usually considered to be key factors facilitating biological invasions. However, specific comparisons of invasion success between sites affected to different degrees by these factors are rare.

2. In this study we related the large-scale distribution of the invading New Zealand mud snail (Potamopyrgus antipodarum) in southern Victorian streams, Australia, to anthropogenic land use, flow variability, water quality and distance from the site to the sea along the stream channel.

3. The presence of P. antipodarum was positively related to an index of flow-driven disturbance, the coefficient of variability of mean daily flows for the year prior to the study.

4. Furthermore, we found that the invader was more likely to occur at sites with multiple land uses in the catchment, in the forms of grazing, forestry and anthropogenic developments (e.g. towns and dams), compared with sites with low-impact activities in the catchment. However, this relationship was confounded by a higher likelihood of finding this snail in lowland sites close to the sea.

5. We conclude that P. antipodarum could potentially be found worldwide at sites with similar ecological characteristics. We hypothesise that its success as an invader may be related to an ability to quickly re-colonise denuded areas and that population abundances may respond to increased food resources. Disturbances could facilitate this invader by creating spaces for colonisation (e.g. a possible consequence of floods) or changing resource levels (e.g. increased nutrient levels in streams with intense human land use in their catchments).

Detection and habitat use of the rufous bristlebird (Dasyornis broadbenti) in coastal heathland, in south-western Victoria, Australia

The Rufous Bristlebird (Dasyornis broadbenti) is a sedentary, ground-dwelling passerine of southern Australia, which is listed as nationally vulnerable, and as near-threatened (lower risk) in Victoria. The species inhabits a variety of vegetation, including shrub thickets in coastal gullies to heathlands on limestone cliffs. This study aimed to assess the size, distribution and habitat use of a population of the subspecies D. b.  broadbenti at Portland in south-western Victoria. Monthly surveys (2002–03) were conducted on foot for 1 h after official sunrise and 1 h before official sunset, and presence of Bristlebirds recorded using vocalisations and sightings. Observations outside of the survey times were also recorded to estimate the size of territories and core area of occupancy. To quantify habitat preferences, vegetation composition and structure were measured in areas where Bristlebirds were present, as well as surrounding areas where they were not detected. The population in the survey areas was estimated at between 70 and 86 individuals in the 170-ha survey area. The estimated size of territories of eight selected pairs of Bristlebirds ranged from 0.5 to 3 ha, with core areas of occupancy ranging from 0.2 to 0.6 ha. During the nesting season (August November) Bristlebirds were detected at greater frequencies in the core area of occupancy within each territory. Significant associations were found between the presence of Bristlebirds and floristic associations dominated by the native environmental weeds Acacia sophorae and Leptospermum laevigatum. Bristlebird presence was significantly positively correlated with increasing vegetation density in the mid-canopy level (80–120 cm) indicating that vegetation structure is a key factor in habitat use.

The normative distribution of chest tube drainage volume after coronary artery bypass grafting

Background
Little evidence exists to describe expected volumes of chest tube (CT) drainage after coronary artery bypass grafting (CABG).

Objectives
The study objective was to map the trajectory of CT drainage volumes from insertion to removal after CABG.

Design

This was a retrospective, descriptive study.
Patients
The study included 239 patients who underwent CABG at a single metropolitan hospital in Melbourne, Australia.

Results
The sample (N = 234), aged 68.7 years (standard deviation [SD] 9.9), was predominantly male (N = 185, 79.1%). The mean duration of CT insertion was 45.2 hours (SD 26.7), and total drainage volume was 1300.6 mL (SD 763.8). Drainage volumes plateau to 31 mL per hour, 8 hours after surgery. From 24 to 48 hours, the mean drainage was 21 mL per hour. Drainage volumes varied between genders.

Conclusions
Evidence of similar drainage patterns in other populations is difficult to locate. If the pattern of drainage shown in this study is consistent, experimental intervention studies comparing standard removal time and earlier removal are recommended. If not, prospective collection of relevant preoperative, intraoperative, and postoperative factors across multiple sites is necessary to determine which patient or practice variations influence CT drainage patterns after CABG.

Baseline assessment of metals and hydrocarbons in the sediments of Lake Mulwala, Australia

An assessment of hydrocarbon and metal/metalloids (arsenic, cadmium, copper, lead, mercury, selenium, zinc) contamination in sediments from Lake Mulwala, Australia, was undertaken. The objectives of the study were: (i) to determine the extent of contamination in the lake sediments, compared to Australian and international sediment quality guidelines, and (ii) to attempt to identify the contaminant sources to the lake. With the exception of a few samples containing elevated levels of arsenic and/or mercury, the levels of all contaminants in the sediment samples taken from the lake were below the 'lower trigger' of the Australian Sediment Quality Guidelines that would warrant further investigation. High molecular weight hydrocarbons (up to 700 mg kg−1) were found in most sediment samples. Non-metric statistical analysis indicated that the contaminant distribution was different in different parts of the lake, with the lowest concentrations generally found at the influent to the lake. No definitive source(s) of contamination could be identified for either metalloids or hydrocarbons.

Public finance and income redistribution in interwar Australia: towards a class analysis

In this paper I focus on a neglected aspect of Australian political history, the extent to which Australian governments actually redistributed income. The German sociologist Rudolf Goldscheid argued that 'the budget is the skeleton of the state stripped of all misleading ideologies'. In Australia a party that claimed to represent lower income earners, the Labor Party, was a major political force, but did Labor actually make a difference to the distribution of income across social classes, or did Labor's rhetoric of equity merely serve to incorporate workers into the capitalist system? A quantitative approach to the political history of labour may enable us to escape both nostalgia for old labourism (which the Howard years have encouraged) and a simple and undifferentiated rejection of labourism as a reformist agent of social integration.

This paper incorporates some material from a 2005 paper that examined overall expenditure patterns and taxation patterns across the states and Commonwealth from 1910 to 1940 but it goes beyond the aggregate approach of this paper to consider the extent which the varying patterns of taxation and public expenditure across Australia impacted on different social classes during the 1930s. It is very much a preliminary analysis based on existing compilations of taxation statistics. It is a static analysis and does not consider if nominally redistributive taxation and expenditure patterns might be rendered ineffective by consequent interstate migration.

New species of Otionellina and Selenaria (Bryozoa-Cheilostomata) from the South West Shelf, Western Australia

Recent sediment samples recovered from the mid-latitude South West Shelf (SWS) of Western Australia (23°- 32° S) by a scientific team aboard the RV Franklin have produced large numbers of free-living, lunulitiform bryozoans. Among these are three undescribed species, Otionellina boneae sp. nov., Selenaria kayae sp. nov., and Selenaria meganae sp. nov. The Australasian lunulite fauna is both diverse and abundant and the new species bring the total of described taxa to sixty (P. Cook unpub.). Twelve lunulite species have been recorded from the SWS. These findings have extended the known geographical range of several lunulite species.

Rural sports and recreational injuries in Australia: what do we know?

Objective: It is widely recognised that individuals residing in regional or rural areas have poorer health outcomes than those from metropolitan areas. Factors associated with these poorer health outcomes include geographical isolation, population declines, limited health care provision and higher levels of inactivity compared to urban areas. The mental, social and physical health of individuals and communities in rural areas can be improved through active participation in sport and recreation activities. Unfortunately, participation in such activities can potentially lead to injury. There is a suggestion that there is an increased risk of sports injuries in rural areas due to the lack of health professionals and coaching personnel, fewer available volunteers to organise and deliver sport, and the general attitude towards injuries in rural settings.

Results: There is very limited information about the number and types of injuries sustained during participation in sports activities in rural and regional settings. This is largely related to a lack of formal sporting structures and support mechanisms including research funding and trained personnel.

Conclusion: A range of factors need to be implemented to improve safety for sporting and recreational participants in these areas. These include improved monitoring of injury occurrence, stronger promotion of safety initiatives and wider implementation of education strategies.

Exechonella (Exechonellidae: Bryozoa, Cheilostomata) from the recent and miocene of Southern Australia

The cheilostome family Exechonellidae Harmer, 1957 is widely distributed in time and space. The genus Exechonella Duvergier, 1924 has a pan-tropical to subtropical distribution from the Eocene to the Recent and is represented by several Australian species from the Tertiary of Victoria and the Recent ofthe southern and eastern coasts. Some species exhibit a wide range of variation in morphological characters, and one, Exechonella papillata, "appears to be new, and is described here. Nearly all specimens are encrusting, but one Tertiary Victorian species has erect, cylindrical, branching colonies. Recent samples, from a depth range of 40-190 metres, include large colonies of several thousand zooids. Frontal wall structures include marginal septular pores connecting between the visceral and hypostegal coeloms, and frontal foramina. Avicularia and homologous structures derived from frontal septular pores are illustrated. The structure of the frontal foramina in different populations of Tertiary E. marginata, demonstrates a major development of hypostegal coelom not found in other species, but resembling that found in another exechonellid genus, Stephanopora Kirkpatrick, 1888.

Conservation and management of hydromyine rodents in Victoria, Australia

Of the 15 species of native rodents recorded from Victoria, Australia, six became extinct within 70 years of European settlement, and two of the remaining nine are classified as ‘threatened’ and four are classified as ‘near threatened’. Thus, only three species are considered to be adequately conserved. This represents one of the most dramatic mammalian species declines recorded in Australia. All the threatened species belong to the subfamily Hydromyinae, the Australian ‘old endemics’. Of the extinct species, four were recorded only from the semi-arid north-west of the state and two from dry woodlands in the central and southern regions. The two  endangered species are the smoky mouse, which has a disjunct distribution from near-coastal to sub-alpine habitats, and the New Holland mouse, which is the most geographically restricted species. Discovered in Victoria only in 1970, it has become extinct at several locations and is the subject of a major recovery program that includes captive breeding and reintroduction. Conservation protocols and practices for Victoria’s native rodents are implemented under state legislation, but lack of basic ecological information makes their conservation a difficult task.

A theory of injustice: the flip side of the relocation coin in Australia

Problems attached to relocation cases in Australia because of geographical and cultural reasons - the best interests of the child principle inherently promotes injustice in relocation cases - operation of Part VII of the Family Law Act in the context of relocation cases - assessment of the best interests of the child principle in Australian relocation cases - responsibility of contact parents - reforming Australian law to promote an equality of interests.

Benthic habitat mapping in coastal waters of south–east Australia

The Victorian Marine Mapping Project will improve knowledge on the location, spatial distribution, condition and extent of marine habitats and associated biodiversity in Victorian State waters. This information will guide informed decision making, enable priority setting, and assist in targeted natural resource management planning. This project entails benthic habitat mapping over 500 square kilometers of Victorian State waters using multibeam sonar, towed video and image classification techniques. Information collected includes seafloor topography, seafloor softness and hardness (reflectivity), and information on geology and benthic flora and fauna assemblages collectively comprising habitat. Computerized semi-automated classification techniques are also being developed to provide a cost effective approach to rapid mapping and assessment of coastal habitats.

Habitat mapping is important for understanding and communicating the distribution of natural values within the marine environment. The coastal fringe of Victoria encompasses a rich and diverse ecosystem representative of coastal waters of South-east Australia. To date, extensive knowledge of these systems is limited due to the lack of available data. Knowledge of the distribution and extent of habitat is required to target management activities most effectively, and provide the basis to monitor and report on their status in the future.

IFIP TC3/WG3.6 : Quality education @ a distance : IFIP TC3/WG3.6 Working Conference on Quality Education @ a Distance, February 3-6, 2003, Geelong, Australia

This work considers several aspects of providing quality education at a distance - quality of systems that support online learning, quality support infrastructure, quality of technical access and support, materials distribution. Issues in each of these areas are considered.