Conservation ecology and breeding biology of the white-browed treecreeper, Climacteris affinis

The White-browed Treecreeper Climacteris affinis is one of many woodland-dependent birds that are at risk from the encroachment of human-dominated land-uses into natural landscapes. The White-browed Treecreeper inhabits semi-arid woodlands in north-west Victoria, Australia, a vegetation community that has undergone extreme modification in the last century due to the expansion of agriculture in the region. Extant woodlands represent only 10% of the original woodland cover in the region, and are highly fragmented and disturbed in many districts. Thus, the survival of the White-browed Treecreeper may depend on active management. However, current knowledge of the ecology and biology of this species is virtually non-existent, and inadequate for informed and effective conservation actions. The aim of this thesis is to redress this situation and provide the ecological basis for sound conservation management of the species. The thesis consists of two parts: an investigation of habitat use at three spatial scales and a study of the social organization, nesting requirements, breeding behaviour and reproductive success of a population of White-browed Treecreepers. Fifty-six patches of remnant woodland in north-west Victoria were surveyed to determine the factors affecting the occurrence of the White-browed Treecreeper at the regional scale. It was detected in 16 patches, and was largely confined to two core districts - Yarrara and, Wyperfeld (Pine Plains). The floristic composition of the dominant tree species was an important determinant of patch occupancy, with the results providing quantitative support for the previously suspected affinity for Belah Casuarina pauper and Slender Cypress-pine Callitris gracilis — Buloke Allocasuarina luehmannii woodlands. However, the absence of the White-browed Treecreeper from several districts was due to factors other than a lack of appropriate habitat. Demographic isolation - the distance from the focal patch to the nearest population of the White-browed Treecreeper - was the most important variable in explaining variation in patch occupancy. Patches isolated from other treecreeper populations by more than 8.3 km in landscapes of non-preferred native vegetation, and 3 km in agricultural landscapes, were unlikely to support the White-browed Treecreeper. The impact of habitat loss and fragmentation on the capacity of individuals to move through the landscape (i.e. functional connectivity) is considered in relation to disruption to dispersal and migration, and the potential collapse of local metapopulations. Habitat use was then examined in a network of patches and linear strips of Belah woodland embedded in a predominantly cultivated landscape. A minimum area of 18.5 ha of Belah woodland was identified as the most important criterion for patch occupancy at the local scale. This landscape appeared to be permeable to movement by the White-browed Treecreeper, facilitated by the extensive network of linear habitat, and clusters of small to medium fragments. The third scale of habitat use investigated the frequency of use of 1-ha plots within tracts of occupied woodland. It is important to discriminate between habitat traits that operate at the population level, and those that act as proximate cues for habitat selection by individuals. Woodlands that have high tree density, extensive cover of low-stature shrubs, abundant lichen, a complex vertical structure, and relatively low cover of grass and herbs are likely to support larger populations of the White-browed Treecreeper. However, individuals appeared to be using tree dominance (positive) and tall shrub cover (negative) as proximate environmental stimuli for habitat selectivity. A relatively high cover of ground lichen, which probably reflects a ground layer with low disturbance and high structural complexity, was also a reliable indicator of habitat use. Predictive models were developed which could be used to plan vegetation management to enhance habitat for the White-browed Treecreeper. The results of the regional, landscape and patch-scale investigations emphasise that factors operating at multiple spatial scales influence the suitability of remnant vegetation as habitat for the White-browed Treecreeper. The White-browed Treecreeper is typical of many small Australian passerines in that it has high annual survival, small clutches, a long breeding season, multiple broods and relatively low reproductive rates. Reproductive effort is adjusted through the number of clutches laid rather than clutch size. They occupy relatively large, all-purpose territories throughout the year. However, unlike many group territorial birds, territory size was not related to the number of occupants. The White-browed Treecreeper nests in tree hollows. They select hollows with a southerly orientation where possible, and prefer hollows that were higher from the ground. At Yarrara, there was considerable spatial variation in hollow abundance that, in concert with territorial constraints, restricted the actual availability of hollows to less than the absolute abundance of hollows. Thus, the availability of suitable hollows may limit reproductive productivity in some territories, although the magnitude of this constraint on overall population growth is predicted to be small. However, lack of recruitment of hollow-bearing trees would increase the potential for hollow availability to limit population growth. This prospect is particularly relevant in grazed remnants and those outside the reserve system. Facultative cooperative breeding was confirmed, with groups formed through male philopatry. Consequently, natal dispersal is female-biased, although there was no skew in the sex ratio of the fledglings or the general adult population. Helpers were observed performing all activities associated with parenting except copulation and brooding. Cooperatively breeding groups enjoyed higher fledgling productivity than simple pairs, after statistically accounting for territory and parental quality. However, the difference reflected increased productivity in the 1999-breeding season only, when climatic conditions were more favourable than in 1998. Breeding commenced earlier in 1999, and all breeding units were more likely to attempt a second brood. However, only breeders with helpers were successful in fledging second brood young, and it was this difference that accounted for the overall discrepancy in productivity. The key mechanism for increased success in cooperative groups was a reduction hi the interval between first and second broods, facilitated by compensatory reductions in the level of care to the first brood. Thus, females with helpers probably achieved significant energetic savings during this period, which enabled them to re-lay sooner. Furthermore, they were able to recommence nesting when the fledglings from the first brood were younger because there were more adults to feed the dependent juveniles. The current utility, and possible evolutionary pathways, of cooperative breeding is examined from the perspective of both breeders and helpers. Breeders benefit through enhanced fledgling productivity in good breeding conditions and a reduction in the burden of parental care, which may impart significant energetic savings. Further, breeders may facilitate philopatry as a means for ensuring a minimum level of reproductive success. Helpers benefit through an increase in their inclusive fitness in the absence of opportunities for independent breeding (i.e. ecological constraints) and access to breeding vacancies in the natal or adjacent territories (i.e. benefits of philopatry). However, the majority of breeding unit-years comprised unassisted breeders, which suggests that pairs are selectively favoured under certain environmental or demographic conditions.

Evolution and everging trends of university writing groups

Writing groups have developed in universities to assist academics to publish. Knowledge of these groups and their successes and challenges is valuable, and informs the wider academic writing community. However there is a paucity of research in this support area. This article will discuss writing groups from two other universities and report on the evolution of our writing group over a three-year period. It will then compare the characteristics of the three in terms of publishing acumen, collegiality, leadership and affect, and discuss emerging trends.

Historical evolution and modern implications of concepts of consent to, and refusal of, medical treatment in the law of trespass

Many mischiefs arise on the change of a maxim and rule of the Common Law, which those who altered it could not see when they made the change.

Contact pressure evolution and its relation to wear in sheet metal forming

For a given sheet metal forming process, an accurate determination of the contact pressure distribution is an essential step towards the estimation of tool life. This investigation utilizes finite element (FE) analysis to model and explain the evolution and distribution of contact pressure over the die radius, throughout the duration of a channel forming process. It was found that a typical two-peak steady-state contact pressure response exists for the majority of the process. However, this was preceded by an initial transient response, characterized by extremely large and localized contact pressures, which were more than double the magnitude of the steady-state peak pressure. The validity of the predicted contact pressure behavior was assessed via detailed numerical analysis and by examining the wear response of an experimental stamping operation. The experimental results revealed that the high contact pressure zones of the transient response corresponded to a severe galling wear mechanism. Therefore, the transient response may be of primary significance to the tool wear response; thus questioning the applicability of traditional bending-under-tension wear tests for sheet metal stamping processes. Finally, a parametric study was conducted, examining the influence of the major process parameters on the steady-state and peak transient contact pressures, using the developed FE model. It was found that the bend ratio and the blank material ultimate tensile strength had the most influence on the peak contact pressures. The main process-related parameters, friction coefficient and blank holder force, were found to have only a minor influence.

The microstructure evolution and mechanical properties of cryorolled Al alloys

A solutionized Al2024 alloy was subjected to rolling at liquid nitrogen temperature (cryorolling) resulting in an ultra-fine stmcture. The material was also subjected to recovery annealing at 160°C. The ultrafine structured material demonstrated increased strength but very low ductility. The uniform elongation of the material after recovery annealing increased without any sacrifice of strength.

The evolution and conservation of Taiwan's aboriginal art heritage

This thesis synthesises perspectives from heritage, museum studies, anthropology and contemporary art to provide a dynamic account of the role of art among the Aboriginal peoples of Taiwan. It proposes that the continuing practice of contemporary Aboriginal art in Taiwan is an important instrument for maintaining Aboriginal groups' cultural vitality.

An overview of the ecology, management and conservation of Australia's temperate woodlands

Australia’s temperate woodlands are environments of cultural and ecological importance and significant repositories of Australia’s biodiversity. Despite this, they have been heavily cleared, much remaining vegetation is in poor condition and many species of plants and animals are threatened. Here, we provide a brief overview of key issues relating to the ecology, management and policy directions for temperate woodlands, by identifying and discussing ten themes. When addressing issues relating to the conservation and management of temperate woodlands, spatial scale is very important, as are the needs for a temporal perspective and a complementary understanding of pattern and process. The extent of landscape change in many woodland environments means that woodland patches, linear networks and paddock trees are critical elements, and that there can be pervasive effects from ‘problem’ native species such as the Noisy Miner (Manorina melanocephala). These consequences of landscape change highlight the challenge to undertake active management and restoration as well as effective monitoring and long-term data collection. In developing approaches for conservation and management of temperate woodlands, it is essential to move our thinking beyond reserves to woodland conservation and management on private land, and recognise the criticality of cross-disciplinary linkages. We conclude by identifying some emerging issues in woodland conservation and management. These include the need to further develop non-traditional approaches to conservation particularly off-reserve management; the value of documenting approaches and programmes that demonstrably lead to effective change; new lessons that can be learned from intact examples of temperate woodlands; and the need to recognise how climate change and human population growth will interact with conservation and management of temperate woodlands in future decades