Palaeomagnetic results from sediments of the Perth Basin,Western Australia,and their bearing on the timing of regional lateritisation

In an attempt to extend palaeomagnetic investigation of Late Palaeozoic and Mesozoic rock formations in Australia, 222 oriented samples have been collected from sedimentary horizons in the Perth Basin and adjacent areas. The thermal stability of the remanent magnetism has been established, but its direction remained oriented close to the direction of the present local geomagnetic field, irrespective of the age of formation sampled. Further attempts to partially demagnetise some specimens using chemical techniques also failed to isolate the primary component of magnetisation. The results have been interpreted as indicating an episode of “blanket” remagnetisation which occurred during the period of regional lateritisation. The presence of normal and reversed polarities indicates that remagnetisation occurred over an extended period of time. By comparing the paleomagnetic pole positions with the apparent polar-wander curve recognised for the Cenozoic of Australia, quantitative support for a Late Oligocene to Early Miocene age for the period of lateritisation is given. Other palaeomagnetic evidence suggests this age may be correlated to laterites in Northern Territory.     

Home and Away: The Grounding of New Football Teams in Perth,Western Australia

Metropolitan sporting, and particularly football, competitions were established in all of Australia's colonial state capital cities about a century ago. Typically, they were comprised of teams from and were supported by the inhabitants of working‐class, inner suburbs. These competitions were the primary foci of Australians' sporting interest and loyalty for almost a century. But, with the shift of public attention and private capital to national competitions, the former stadia of many local clubs have become redundant spaces in what are now gentrifying inner suburbs. Simultaneously new, and even old, national league teams have sought larger, more modern (near) city centre venues for their operations. In this context, two new national league teams in Perth—Fremantle Dockers and Perth Glory—have experienced considerable challenges in establishing both physical ‘homes’ and local identities. These have included both the supplanting of traditional local clubs and the placating of new kinds of inner suburban residents.     

Molluscan grazing and macroalgal zonation on a rocky intertidal platform at Perth,Western Australia

Abstract Intertidal limestone platforms off Perth show a characteristic pattern of algal zonation, with dense macroalgal beds nearshore bounded by a ‘barren zone’ along the seaward edge. Abalone (Haliotis roei) and several species of limpets and chitons are abundant in the barren zone, which is generally devoid of non-coralline macroalgae. The relative importance of abalone versus limpets and chitons in limiting macroalgal abundance in the barren zone was evaluated by manipulating the presence of each group in a factorial experiment. Percentage algal cover was measured photographically in 0.25m² plots at 1–2 month intervals for 9 months. Mean algal cover (mainly the foliose green alga, Ulva rigida) was highest in plots where all grazers were excluded (77–99%), intermediate where only limpets and chitons were excluded (37–85%), and lowest where only abalone were excluded (4–30%) or where no grazers were excluded (2–19%). The effect of limpets and chitons accounted for 55–89% of the variance in total algal cover, whereas the effect of abalone generally accounted for <10% of the variance. Similar results were obtained in terms of the biomass of Ulva rigida at the end of the experiment. Haliotis roei are relatively large and sedentary herbivores, feeding mainly on drift algae. Their effect on algal abundance was mediated both through pre-emption of space, which might otherwise be colonized by algae, and by grazing around their home scar. Limpets and chitons are smaller than abalone, but were much more abundant. Intensive grazing of the reef surface by limpets and chitons precluded the establishment of non-coralline macroalgae, even where abalone were absent.     

Seasonal changes in a honeyeater assemblage in Banksia woodland near Perth,Western Australia

Abstract

Honeyeaters were the most numerous birds in banksia woodland near Perth, Western Australia, throughout the year. Numbers were greatest in a Banksia littoralis swamp, but only during those few months when it contained large amounts of nectar. In the surrounding woodland, numbers were lower but fairly constant during the year. This reflects the smaller amounts of nectar produced throughout the year, by the overlapping flowering patterns of several Banksia and Adenanthos species.

Large and medium-sized honeyeaters (wattlebirds and New Holland Honeyeaters) and flocking silvereyes dominated the swamp when it flowered. In contrast, small honeyeaters (spinebills and Brown Honeyeaters), many of whom were highly territorial residents, comprised the majority of the woodland assemblage throughout the year. These observations support a model based upon aggressive defence of rich nectar sources by the larger honeyeater species, and more efficient exploitation of dispersed flowers by smaller honeyeaters.     

Melding of research and practice to improve restoration of Banksia woodlands after sand extraction,Perth, Western Australia

A unique, two decade‐long partnership of a government research organization (Botanic Gardens and Parks Authority) and an industry partner (Hanson Construction Materials) has enabled the restoration and management of Perth's Banksia woodland after sand extraction to be seriously tackled.     

Control of the exotic bulb, Yellow Soldier (Lachenalia reflexa) invading a Banksia woodland, Perth, Western Australia

Summary In recent times managers have become increasingly aware of the South African bulbous species Yellow Soldier ( Lachenalia reflexa ) becoming a serious weed of bushland on the Swan Coastal Plain. In 1998, trials were implemented to investigate control options for Yellow Soldier invading the understorey of a Banksia ( Banksia attenuata ) Woodland west of Perth. Our trials showed that hand removal over two seasons left all natives intact but was very labour intensive, only reducing cover of Yellow Soldier by 44%. It also triggered germination by ephemeral weeds. Wiping the leaves of individual plants with a 10% glyphosate solution was not effective and was also highly labour intensive. Spot spraying with metsulfuron methyl at 0.2 g/15 L (5 g/ha) reduced the cover of Yellow Soldier by 65%, was easier to implement and appeared to have had insignificant effects on natives. We hope that this trial will encourage other workers in the field to undertake controlled trials to refine treatments at restoration sites.     

Comparisons of habitat structure and plant,arthropod and bird diversity between mainland and island sites near Perth,Western Australia

Detailed estimations of habitat structure, plant species diversity and diversity of arthropods were made at six 4.0 ha sites, two on mainland Western Australia near Perth and four on adjacent islands. The number of resident passerine bird species was also recorded at each site. Plant species diversity, and horizontal foliage diversity (=patchiness) varied only slightly between sites. There were significant positive correlations between arthropod Order diversity and bird diversity, and between vertical foliage diversity and bird diversity. In both Acacia and dune scrub, the Rottnest Island sites had more individuals of arthropods than the mainland sites but these belonged to fewer Orders. Numerical imbalance between arthropod Orders on Rottnest Island probably results from diminution of predators (passerine birds) there. As the actual number of arthropods is higher on the islands, the absence of so many species of passerine birds may result from other factors (ecological and historical).     

Myxomycetes from the Kimberley Region, Western Australia

An account of the Myxomycetes of the Kimberley Region of north Western Australia is presented. It is based on collections obtained mainly from the Napier and Oscar Ranges during the Kimberley Research Project, 1988. The thirty-two collections represent eighteen species, four of which are new records for Australia and twelve new to Western Australia. All but one are new to the Kimberley region, from where only four species were previously known.     

Dads make a difference: an exploratory study of paternal support for breastfeeding in Perth, Western Australia

Background

The ability to breastfeed and continue the practice requires dedication, commitment, persistence and support. Mothers often need to overcome many obstacles to successfully breastfeed their babies and maintain their balance of home, family and work commitments. Evidence suggests that fathers want to be involved and be part of the parenthood process, including infant feeding. The role transition from couple to family poses challenges to both parents. Sharing the experience of childbirth and supporting each other in the subsequent infant feeding practices is one of those challenges.

Methods

A qualitative exploratory design was chosen to identify parents' perceptions of what constitutes support for breastfeeding, particularly focusing upon paternal support. Focus groups were conducted with mothers and a focus group, interviews and an online survey were developed for fathers. Thematic analysis was used to identify the main themes.

Results

From a total of 76 participants, the major theme emerging from mothers' data identified that "Dads do make a difference". Three sub-themes included: Anticipating needs and getting the job done; Encouragement to do your best; and Paternal determination and commitment, associated with effective partner support. "Wanting to be involved" was identified from fathers' data as the major theme around their needs. Three sub-themes included: Wanting more information; Learning the role; and Being an advocate.

Conclusion

Sharing the experience of childbirth and supporting each other in the subsequent infant feeding practices was perceived as the best outcome for the majority of new mothers and fathers. Paternal emotional, practical and physical supports were identified as important factors to promote successful breastfeeding and to enrich the experience for the mother and subsequently the father.

Trail Regristration

Australia and New Zealand Clinical Trials Registry: ACTRN12609000667213.     

Eubrachythoracid arthrodires from Gogo, Western Australia

Two monotypic genera of coccosteoid eubrachythoracid arthrodires are described from the Upper Devonian Gogo Formation of Western Australia as Compagopiscis gen. nov. and Gogopiscis gen. nov. They are most closely related to Torosteus Gardiner & Miles, also from the Gogo Formation, and all three are placed in the family Plourdosteidae Vezina, 1990; Compagopiscis and Gogopiscis are jointly the sister-group of Torosteus.     

Assessing Health Risks from Pesticides in Recycled Water: A Case Study of Augmentation of Drinking Water Supplies in Perth,Western Australia

A characterization of pesticides in secondary treated effluent (STE) and a screening health risk assessment were conducted to evaluate potential health impacts of recycled water for potable reuse. Samples of STE were examined pre- and post-reverse osmosis (RO) treatment in two plants. Risk quotients (RQ) were estimated by expressing the maximum and median concentration as a function of the health value. Of 128 pesticides analyzed, 11 were detected in STE. Trifluralin was detected in 86.5% of the STE samples followed by metolachlor (67.6%), 2,4-D (50%), and propiconazole (42.5%). Metolachlor was the only pesticide detected post-RO in one sample (0.08 μg/L, limit of reporting = 0.05 μg/L). RQ(max) were all below health values in the STE with the exception of thiophanate methyl (RQ max = 2.4). RO was able to reduce the concentration of all pesticides below LOR. Median removal efficiency for RO ranged from 67.1% (atrazine) to 98.8% (2,4-D). The results indicate that, despite the detection of pesticides in STE, the impact on indirect potable reuse is negligible due to the low concentrations in STE and their subsequent removal during RO treatment. Implementation of risk management strategies to optimize safety and recommendations for a monitoring program are also discussed.     

Corticioid fungi from the Kimberley Region,Western Australia

Summary  Corticioid fungi from the Kimberley Region of Western Australia are reviewed. 31 species are reported, of which five, Aleurodiscus kimberleyanus, Athelopsis vesicularis, Dendrothele cornivesiculosa, Hyphoderma tubulicystidium, and Phanerochaete subcrassispora are described as new. Grandinia glauca is given the new combination Grammothele glauca, and Hydnum investiens the new combination Phanerochaete investiens. A further eight species are recorded which have not previously been reported from Australia.     

Impact of fire on leaf nutrients,arthropod fauna and herbivory of native and exotic eucalypts in Kings Park,Perth, Western Australia

The vegetation of Kings Park, near the centre of Perth, Western Australia, once had an overstorey of Eucalyptus marginata (jarrah) or Eucalyptus gomphocephala (tuart), and many trees still remain in the bushland parts of the Park. Avenues and roadsides have been planted with eastern Australian species, including Eucalyptus cladocalyx (sugar gum) and Eucalyptus botryoides (southern mahogany), both of which have become invasive. The present study examined the effect of a recent burn on the level of herbivory on these native and exotic eucalypts. Leaf damage, shoot extension and number of new leaves were measured on tagged shoots of saplings of each tree species in unburnt and burnt areas over an 8‐month period. Leaf macronutrient levels were quantified and the number of arthropods on saplings was measured at the end of the recording period by chemical knockdown. Leaf macronutrients were mostly higher in all four species in the burnt area, and this was associated with generally higher numbers of canopy arthropods and greater levels of leaf damage. It is suggested that the pulse of soil nutrients after the fire resulted in more nutrient‐rich foliage, which in turn was more palatable to arthropods. The resulting high levels of herbivory possibly led to reduced shoot extension of E. gomphocephala, E. botryoides and, to a lesser extent, E. cladocalyx. This acts as a negative feedback mechanism that lessens the tendency for lush, post‐fire regrowth to outcompete other species of plants. There was no consistent difference in the levels of the various types of leaf damage or of arthropods on the native and the exotic eucalypts, suggesting that freedom from herbivory is not contributing to the invasiveness of the two exotic species.