Floodplain wetlands of the Gellibrand estuary: What type of invertebrate community

Introduction. Along the south coast of Australia, wetlands on the floodplains of lowland rivers and estuaries have been severely altered by agriculture and urbanization. Efforts to restore or rehabilitate these wetlands are hampered by insufficient knowledge of the original condition of these wetlands, or their variability in time and space. This research describes the macroinvertebrate community of wetlands on the floodplain of the Gellibrand River and estuary, which has suffered comparatively few human impacts. The aim of the research was to describe the variability of macroinvertebrate communities as a baseline for the future management of these wetlands, and to contribute to the general understanding of estuary-floodplain wetlands, thereby improving the basis for their management.

The Gellibrand River has a catchment area of approximately 1200 km2 draining the western slopes of the Otway Ranges, and entering the Southern Ocean at Princetown. From a mean annual flow of 315 000 mL, 25 000 mL are removed per annum for agricultural and domestic use (O'May & Wallace 2001), and flows are closer to natural regimes than most other Western Victorian rivers. The estuary is a bar-built, salt-wedge estuary that becomes completely blocked by the sand bar in most years, during summer and autumn. Over past decades, the estuary mouth has been opened artificially in most years. to prevent flooding of agricultural land and roads adjacent to the wetlands. At its maximum, the salt-wedge penetrates approximately 10 km upstream from the river mouth, but the estuary may also be completely fresh during high winter discharge
(Mckay 2000).

The wetlands surrounding Princetown cover 119 ha and are listed as nationally important (Environment Australia 2001). This listing regards the wetlands as an important habitat for animals at vulnerable stages of their life cycle and a refuge from adverse conditions, such as drought. They are a good example of coastal brackish and freshwater marshes, with an important ecological and hydrological role as part of a large wetland
complex.

Phytophthora cinnamomi in native vegetation communities of southern Victoia - morphological variation and paragyny among isolates

Morphology has often been used as an indicator of variability within species. The present study investigated morphological and physiological characteristics of isolates of Phytophthora cinnamomi collected from diseased vegetation communities at Anglesea, Victoria, and isolates collected from other regions in the State. Characteristics studied included growth rate on potato-dextrose agar (PDA), corn-meal agar and V8-juice agar at 24°C, growth rate on V8 agar at 15°C, colony morphology on PDA, sporangial and gametangial morphology, sporangial production and mating type. Phenotypic variation was demonstrated in radial growth rate, colony morphology and sporangial dimensions. Sporangial and oogonial dimensions and sporangial production were not significantly different between isolates from different geographical regions. All isolates were found to be of the A2 mating type suggesting variation was derived asexually. Paragynal associations, in an organism characteristically defined as amphigynal, were observed following crossing with A1 isolates. This is the first such study undertaken in southern Victoria. The findings highlight the importance of appropriate management of an area of such high conservation value as the Anglesea Heath to contain the current infection and to prevent introduction of new isolates into the area.

Soft-sediment deformation structures in the middle permian Wandrawandian siltstone, southern Sydney basin: implications for depositional environment and basin tectonics

The Middle Permian Wandrawandian Siltstone at Warden Head near Ulladulla in the southern Sydney Basin is dominated by fossiliferous siltstone and mudstone, with a large amount of dropstones (lonestones) and some pebbly sandstone beds. Two general types of deposits are recognised from the cliff succession in view of the timing and mechanism of their formation. One is represented by the background (or primary) deposits of offshore to slope environments with abundant dropstones of glacial marine origin. This facies occurs throughout the cliff sections at Warden Head. The second type is distinguished by secondary, soft-sediment deformational deposits and structures of the primary (background) deposits, and comprises three successive layers of sandy mudstone dikes. In the second type of deposit, metre scale, laterally extensive syn-depositional slump deformation structures occur extensively in the middle part of the Wandrawandian Siltstone. The deformation structures vary in morphology and pattern, including large-scale complex-type folds, flexural stratification, concave-up structures, small-magnitude -faults accompanied by folding and brecciation. The slumps and associated syn-depositional structures are herein attributed to penecontemporaneous deformations of soft sediments (mostly mud and silty mud), formed as a result of mass movement of unconsolidated and/or semi-consolidated substrate following earthquake events. The occurrence of the earthquake event deposits (or seismites) at Warden Head supports the current view that the Sydney Basin was located in a back-arc setting near the New England magmatic arc on an active continental margin during the Middle Permian, and the timing of the earthquake events is here interpreted to indicate the onset of the Hunter Bowen Orogeny in the southern Sydney Basin.

Soft-sediment deformation structures interpreted as seismite from the Middle Permian of the southern Sydney Basin, southeastern Australia

The Middle Permian Wandrawandian Siltstone of the southern Sydney Basin is well exposed along the coastline from Lagoon Head in the south to North Head in the north near Ulladulla in southern New South Wales. The unit is dominated by fossiliferous siltstone and mudstone, with abundant dropstones and minor pebbly sandstone interbeds, and contains an interval of well-preserved and extensive soft-sediment deformation structures. These deformation structures occur mainly in the middle part of the cliff sections and are bounded above and below by undeformed sedimentary units of similar lithology. A wide range of soft-sediment deformation structures have been observed, including cracks, sandstone and sandy mudstone dykes, a possible sand volcano, networks of relatively small and closely connected fissure-like structures, metre-scale complex-type slump folds, flexural stratification, concave-up depressional structures, small-scale normal faults (with displacements usually <1 m), shear planes, and breccias (pseudonodules). The slumps and associated deformations are here collectively interpreted as representing a seismite deposit attributable to penecontemporaneous deformation of soft, hydroplastic sediment layers following a liquefaction triggered by seismic shocks. The timing of the inferred earthquake events appears to correspond to the onset of a major basin-wide tectonism during the Middle Permian.

Southern drift : the learning styles of first and third-year students of the built environment

This paper investigates learning processes across a built environment design curriculum through the recognition of the four learning styles defined in the experiential learning theory of Kolb, i.e., 'accommodating', 'diverging', 'assimilating' and 'converging.' The paper focuses on the results of a cross-curriculum learning style survey. The results of the survey appear to explain why many prior studies of the personality characteristics, learning and cognitive styles of practitioners and of design students at different stages of their education appear conflicting. The hypothesis tested to resolve these inconsistencies asked whether design-learning styles are fixed or change as students' progress through their studies. The survey provides evidence of a statistically significant relationship between learning styles and year of study. The evidence suggests a southern drift (the term refers to the spatial interrelationship of styles in the two-dimensional Kolb Learning Style Index [LSI] cycle) towards the abstract conceptualisation mode of the learning process as students near the completion of their studies. This fluidity in learning style remains a hypothesis until further research is able to study one cohort for the entirety of a degree program. The paper argues that the possibility of learning style fluidity needs determining if learning style theory is to provide a workable model for informing the teaching of architecture.

Lopingian (Late Permian) stratigraphy, sedimentation and palaeobiogeography in southern Tibet

Investigations of the Permian-Triassic sections and limestone blocks scattered in the Indus-Tsangbo Suture Zone in southern Tibet show widespread distribution of the Lopingian strata. The Lopingian deposits mostly contain rich brachiopod fossils and characteristic conodonts of the Mesogondolella shenz Zone of latest Changhsingian age in the topmost part. Brachiopod assemblages are largely comparable with those known from the upper Wargal and Chhidru Formations of the Salt Range, Pakistan, the Zewan Formation of Kashmir, the upper part of the Kuling Group in Spiti of India and the Hardman Formation of Western Australia. A revised Lopingian (Late Permian) age is proposed for the Selong Group and its equivalents in southern Tibet. The Lopingian deposits in southern Tibet can be grouped into three different sedimentary types, each of which reflects different sedimentary environments from coastal to continental shelfal settings on the northern peri-Gondwanan margin. The Qubu-type sequence represents marine coastal and proximal barrier-lagoon sediments during a gradual sea-level rise. Micaceous sandstone and shale of regressive origin, with abundant palynomorphs and acritarches, developed during the Late Lopingian sea-level lowstand, which is followed by a major rapid transgression at the very end of Permian. The Selong-type sequence in the Selong area consists of bioclastic limestone and calcareous shale in the lower part, and crinoid grainstone in the upper part. The latter part is believed to have been formed in a high-energy inner shelf shoal setting. The Chitichun-type sequence, sporadically distributed along the Indus-Tsangbo suture zone as small limestone blocks, consists of pure bioclastic sparite with the ammonoid Cyclolobus fauna. It is interpreted as the break-up products of sea-mounts and/or small isolated carbonate build-ups developed on the outer shelfal settings.

Earliest Wuchiapingian (Lopingian, Late Permian) brachiopods in southern Hunan, South China : implications for the Pre-Lopingian crisis and onset of Lopingian recovery / radiation

The uppermost 5-15 m of the Douling Formation in the southern Hunan area. South China, yields a diverse fauna comprised of ammonoids, bivalves, and brachiopods. The brachiopods reported in this paper consist of 51 species in 34 genera and are dominated by the Lopingian (Late Permian) species associated with a few species persisting from the underlying Maokouan (Late Guadalupian). This fauna is of earliest Wuchiapingian in age as precisely constrained by the associated conodont Clarkina postbitteri postbitteri and the Guadalupian-type ammonoid fauna of the Roadoceras-Doulingoceras Zone in the brachiopod horizon. The discovery of the Lopingian species-dominated brachiopod fauna in the earliest Wuchiapingian in southern Hunan suggests a much less pronounced effect of the pre-Lopingian crisis (end-Guadalupian mass extinction) than the end-Changhsingian mass extinction in terms of brachiopods, a contemporaneous onset of the Lopingian recovery/radiation during the pre-Lopingian crisis period, and taxonomic selectivity of the pre-Lopingian crisis in terms of different fossil groups. New taxa are Echinauris doulingensis n. sp., Pararigbyella quadrilobata n. gen. and n. sp. and P. doulingensis n. gen. and n. sp.

Type 2 diabetes prevalence varies by socio-economic status within and between migrant groups: analysis and implications for Australia

Background:
Ethnic diversity is increasing through migration in many developed countries. Evidence indicates that type 2 diabetes mellitus (T2DM) prevalence varies by ethnicity and socio- economic status (SES), and that in many settings, migrants experience a disproportionate burden of disease compared with locally-born groups. Given Australia’s multicultural demography, we sought to identify groups at high risk of T2DM in Victoria, Australia.