This study was aimed at determining the characteristics of the fish assemblages in nearshore coastal waters of the remote Canning region of tropical Western Australia and to obtain sound quantitative data on crucial aspects of the biology of the two threadfin species, which are commercially and recreationally important in those waters. The community studies focused on comparing the species compositions of the fish faunas found over bare sand and in mangroves and rock pools and on elucidating the factors that influence those compositions. The population studies concentrated on exploring the hermaphroditic characteristics, size and age structures, growth and stock status of the two species of Polynemidae. The arid Canning coast of north-western Australia, which lies between Cape Leveuque (16°21'S, 123°02'E) and Cape Keraudren (19°57'S, 119°46'E),does not contain rivers and thus also estuaries, which traditionally provide alternative fish nursery areas to those found in nearshore waters. It is also subjected to some of the largest tides in the world. The fish faunas at three widely-separated locations, i.e. Port Smith, Eighty Mile Beach and Cape Keraudren, were sampled using seine and gill netting in their shallow, nearshore waters and rotenoning in intertidal pools at the first and third of those locations with the aim of determining the following. 1) The extents to which the diversity, abundance and species composition of the fish faunas of the Canning coast are influenced by location, habitat and time of year. 2) Which species use bare sand, mangroves and/or intertidal pools as nursery areas and which are permanent residents in one or more of those habitats. 3) Identification of the commercial and recreational fish species found in each of the above three habitat types and their relative abundance in those habitats. The fish catches from all three sampling locations collectively yielded 170 species representing 66 families. The most abundant species (with % contributions) in seine net samples collected over unvegetated sand were Stolephorus carpentariae (19.1), Herklotsichthys blackburni (14.7) and Atherinomorus lacunosus (11.8), whereas those in gill net samples taken over the same substrate were Arius proximus (26.6), Eleutheronema tetradactylum (18.8) and Polydactylus macrochir (18.7) and in mangroves were A. proximus (38.9), Valamugil buchanani (18.8) and Scomberoides commersonnianus (18.7). Ambassis vachellii (32.5) and Craterocephalus capreoli (14.4) dominated the catches obtained from intertidal pools. Fifty three of the 170 species that were caught are fished commercially and recreationally along the Canning coast and a further 17 fish species are caught solely by recreational fishers. The most abundant of these species were the polynemids E. tetradactylum and P. macrochir, which are residents of nearshore waters, i.e. are found in these waters throughout the whole of their life cycle. Other species, such as Lutjanus russelli Epinephelus coioides and Sillago vittata, are present in nearshore waters only as juveniles and thus use these waters as a nursery. The compositions of the ichthyofaunal samples collected by both seine and gill nets over bare sand differed markedly among locations. The compositions at Cape Keraudren, the most southerly location, were more similar to those at Port Smith, the most northerly and most protected location, than those that Eighty Mile Beach, the most exposed of the three locations. It is thus proposed that the compositions of the fish faunas found in nearshore, unvegetated waters along the Canning coast are influenced more by factors related to turbidity than those reflecting latitudinal position. The fish fauna at Eighty Mile Beach was distinguished by species typically associated with turbid waters, such as those of the Polynemidae and Sciaenidae and certain species of the Engraulidae, Ariidae, Mugilidae and Carcharhinidae. In contrast, many of those species were absent from catches made in the clearer waters of Port Smith, where the ichthyofauna was disitinguished by certain species of the Clupeidae and Atherinidae and other species associated with low turbidity, such as V. buchanani and Chanos chanos. The compositions of the fish faunas sampled over bare sand by gill and seine nets underwent marked seasonal changes. Furthermore, these changes, particularly in the case of seine net catches, tended to undergo a conspicuous cyclical progression during the year as a result of time-staggered changes in the recruitment and emigration of certain species. The species responsible for seasonal differences in either the gill and/or seine net samples included nearshore residents, such as the clupeids H. blackburni and Spratelloides delicatulus, the polynemids E. tetradactylum and P. macrochir, the engraulidid Thryssa hamiltonii and the atherinids A. lacunosus and C. capreoli, as well as species such as the sillaginid S. vittata, which use nearshore waters as a nursery area. At a broader level, the compositions of the fish sampled by gill net in the wet and dry periods were also distinct, reflecting, in particular, the influx of certain species during the wet period, e.g. mature ariid catfish and the juveniles of a number of elasmobranchs, such as the endangered Green Sawfish Pristis zijsron, aggregate in nearshore, shallow waters during this period. The fish faunas of the intertidal pools at Port Smith and Cape Keraudren, which were sampled using rotenone, differed markedly from each other and from those over nearby bare sand substrates on the coast. The ichthyofauna of intertidal pools at Port Smith was distinguished from that at Cape Keraudren by relatively greater numbers of C. capreoli at the former location, whereas the opposite situation pertained with Amniataba caudavittatus, Acanthopagrus latus and L. macrolepis at Cape Keraudren. These differences were attributable to differences in habitat characteristics of intertidal pools, with pools at the former location containing clearer water and greater amounts of rock, while those at the latter contained mangroves. Few species were caught in both intertidal pools and in the surrounding shallow, nearshore waters, demonstrating that the rock pools provide an important habitat for certain fish species. The composition of the fish fauna of intertidal pools at Port Smith underwent an essentially cyclical progression over the course of a year, reflecting the timing and strength of recruitment of the juveniles of the various species. The species responsible for this recruitment-related change in the fish fauna included both nearshore residents, such as A. vachellii, C. capreoli and A. lacunosus, as well as transient species that use intertidal pools as a nursery area, i.e. E. coioides and L. russelli. In contrast, the seasonal progression in species composition in intertidal pools at Cape Keraudren was largely related to the influence of a tropical cyclone. The fish community in the period immediately following the cyclone was depauparate and distinguished, from that before the cyclone, in particular by a lack of A. vachellii and A. latus. The Blue and King Threadfins E. tetradactylum and P. macrochir, which were among the most abundant species in the seine and gill net catches taken in unvegetated waters, are key species in the Kimberley Managed Gill Net and Barramundi Fishery (KMGBF) and important recreational target species. In addition, these species are an important source of food and of cultural significance for local indigenous communities. The importance of the shared nature of these resources and the marked fluctuations undergone by the catches of threadfin in recent years led to the second major component of this thesis, i.e. to obtain reliable data on the reproductive biology, age compositions, growth rates and mortality of E. tetradactylum and P. macrochir, of the type that are required by managers for developing plans to conserve the stocks of these species in north-western Australia. Length and age compositions of male, bisexual (i.e. possessing gonads comprising both testicular and ovarian tissue) and female E. tetradactylum and P. macrochir, and histological characteristics of the gonads of the full size range of threadfin were examined and analysed. The results demonstrate that, in north-western Australian waters, each of these species is a protandrous hermaphrodite, i.e. individuals mature first as males before changing sex to female. Sexual maturity is attained by 50% of male E. tetradactylum and P. macrochir at ca 200 and 230 mm, respectively. For both species, these lengths approximate those attained towards the end of their first year of life. However, the lengths and ages at which these two species typically change sex differ markedly. In the case of E. tetradactylum, gtransitionalh fish (i.e. those with bisexual gonads assumed to be changing sex) were most prevalent at total lengths between 300 and 400 mm. All fish greater than 450 mm total length possessed gonads that consisted exclusively of ovarian tissue. The L50 for sex change from male and transitional fish to females is ca 400 mm. Thus, the majority of E. tetradactylum change sex during their second or third years of life and males are rarely older than three years. In contrast, the range of lengths at which transitional individuals of P. macrochir were recorded was much broader than E. tetradactylum, i.e. between 310 and 1140 mm. The data on the prevalences of males and females in sequential age classes demonstrate that sex change can occur in P. macrochir as young as two years old and up to eight years old. The lengths at which E. tetradactylum changes sex in north-western Australia was relatively similar at all locations, whereas the L50 for sex change in P. macrochir varied markedly among sampling locations. For example, the L50 value for sex inversion was ca 790 mm at Derby, compared with ca 1160 mm at Anna Plains. The differences presumably reflect variations in environmental conditions at those localities. Analysis of the ages of male, transitional and female E. tetradactylum revealed that the change from male to female by this species occurs over a period of ca 6 months. The presence of mature sperm in transitional gonads, in combination with trends exhibited by the GSIs of the testicular and ovarian portions of transitional gonads, demonstrate that, during the spawning season, transitional threadfin function as males. Analyses indicate that, once individual E. tetradactylum and P. macrochir change sex to become females, all individuals function as mature females during successive breeding seasons. Both species of threadfin have protracted spawning periods of ca 6 months. However, the monthly trends exhibited by the mean GSIs and the proportion of the various gonad stages show that the spawning of both species peaks during spring and early summer, i.e. September to December, and occurs on multiple occasions each year. In north-western Australia, P. macrochir grows far larger and lives for longer than E. tetradactylum, a difference reflected in the maximum total lengths and ages recorded for these two species, i.e. 1393 mm and 10 years vs 793 mm and 6 years, respectively. In addition, P. macrochir grows faster than E. tetradactylum, attaining lengths of 322, 520 and 945 mm vs 245, 400 and 635 mm, by the end of years 1, 2 and 5, respectively. For both species, estimates of total, natural and fishing mortality were derived using different life history models, simulation based on the number of fish in samples above a specified age, relative abundance analyses and a Monte Carlo resampling approach. The various biological parameters determined for E. tetradactylum and P. macrochir, including the estimates of mortality, were incorporated into yield per recruit, spawning biomass per recruit and spawning potential ratio analyses to determine the current impacts of fishing on each species in north-western Australia. The results of these analyses indicate that E. tetradactylum is fully exploited and that P. macrochir is overexploited. The effectiveness of various management options is evaluated. The data produced during the first part of this thesis on the diversity, abundance and species compositions of fish faunas in different nearshore habitats along the Canning coast of north-western Australia, and the way these faunas are influenced by season, provides fisheries and environmental managers with information that will enable them to develop management plans for these habitats and their fish species. In addition, the biological data for E. tetradactylum and P. macrochir, and the results of the stock assessments performed on these species, will enable fisheries managers to develop plans for conserving the stocks of these two species in north-western Australia.

The Orchidaceae is characterized by a remarkably diverse range of life forms and some of the most highly specialized interactions with soil fungi and insect pollinators found in the flowering plants. Many species are rare or threatened with extinction either directly through loss of habitat or over-collection or, indirectly through debilitation or loss of mycorrhizal association or pollinator capacity. Australian temperate terrestrial orchids represent one of the most threatened groups in the Australian flora with many taxa clinging to existence in urban and rural bushland remnants, road verges and unprotected bushland. The aim of this study is to research and develop integrated conservation based on critical aspects of terrestrial orchid biology and ecology, towards the recovery of the rare and endangered Western Australian terrestrial orchid Caladenia huegelii. This study identified key aspects involved in an integrated conservation approach and research focused on conservation genetics, mycorrhizal interactions and in situ and ex situ conservation strategies for this species. Using polymorphic microsatellite molecular markers, high levels of genetic diversity were found within remnant populations of C. huegelii, while weak differentiation was observed among populations over the species geographic range. These results indicate historic genetic exchange between C. huegelii populations, a possible consequence of the sexually deceptive pollination strategy and the capacity for widespread seed dispersal. Symbiotic germination studies revealed compatibility barriers to C. huegelii germination with the orchid possessing a highly specific orchid-mycorrhizal association relative to common sympatric congeners. These results were reflected in a phylogenetic analysis of DNA sequences, revealing C. huegelii associates with only one endophyte species within the fungal family Sebacinaceae across its geographic range. Large scale in situ seed baiting demonstrated that endophytes compatible with C. huegelii were limited in distribution relative to common and widespread orchid species, a feature for C. huegelii that may be a major contributing factor in limiting the distributional range of the species. Detailed, within site seed baiting methods identified hotspots for mycorrhizal fungus compatible with C. huegelii that were unoccupied by the orchid. These mycorrhizal hotspots where used to investigate the effect of endophyte presence on survival of transplanted mature plants and seedling outplants. The in situ survival of glasshouse propagated seedlings was further optimized by incubating seedlings in growth containers before transfer to soil and outplanting seedlings in their second growing season. The findings of this study will substantially advance the recovery of C. huegelii and provide benchmark knowledge for similar projects with other rare and threatened terrestrial orchid species.

[Truncated abstract] In order to assess the sustainability of mixed plantings on saline land, this thesis examined the importance of leaf-litter trapping and microsites on recruitment in a salt affected alley-belted (tree/shrub) agricultural system in Western Australia. Located in the low rainfall region (MAR <330 mm) of the wheatbelt, the 60 ha site consists of concentric rows of Eucalyptus sargentii trees with mounded (6 - 11 cm high) 10 -15 m inter-rows of Atriplex spp. Sustainability of this system and fulfilment of productive and ameliorative functions is dependant on successful recruitment (perennials). Although the present study site was conducted on farmland in a Mediterranean-type climate, low annual rainfall and spatial arrangement of perennial shrubs and trees, allow useful comparisons to be made with naturally occurring banded semi-arid systems and vice-versa. Of key interest were leaf-litter redistribution and trapping by tree and shrub rows and whether litter-cover/microsites facilitated/interfered with seedling recruitment (establishment, growth and survival). Litter from the tree row, redistributed by prevailing winds and rain, accumulated adjacent to saltbush seeding mounds, creating a mosaic of bare and littered areas across the site (total litter 10 t/ha over 22 months). Accumulated litter was hypothesized to differentially influence seasonal soil abiotic parameters (depending on litter-cover density) including; salinity, water availability, infiltration rates, water repellency and temperature. These abiotic conditions were also hypothesized to vary between tree and shrub microsites. Biotically, recruitment at this site was also hypothesized to be determined by interactions (positive and negative) between perennial components and understorey annuals/perennial seedlings. Accumulation of litter and resultant heterogeneity was influenced by shrub morphology, microtopography, wind direction and distance from litter source, with increased litter on the leeward sides of hemispherical Atriplex undulata shrubs and shrubs closest to tree rows. ... The importance of tree/shrub microsites varied seasonally, with no influence in winter due to moderate temperatures and increased water availability. In warmer months saltbush mid-row microsites were most favourable for seedling recruitment due to moderate litter-cover; reducing salinity, temperatures and increasing infiltration; and reduced root-competition/shading by the tree row. Tree microsites also directly inhibited seedling recruitment through increased salinities and water repellency. However, trees also indirectly facilitated recruitment in adjacent areas through provision of leaf-litter. As litter-trapping and recruitment patterns at this site mirror those found in semi-arid natural and artificial systems, the results of this study provide useful insights into creating appropriate mimics of low rainfall natural banded woodland and chenopod shrublands. Saltbush seeding mounds, shrub morphology and litter were key components for litter trapping and recruitment heterogeneity at this site. In this tree/shrub alley planting, where litter quantities directly influence vegetation cover densities, future saline plantings need to consider appropriate tree/shrub row spacings and orientation for efficient resource (seeds, litter and water) capture.

Over the past 30 years in Western Australia (WA), there has been a heated debate about the future use of the remaining temperate old-growth forests of karri and jarrah in the south-west of the State. This debate revolved around policy proposals from two social movements: one social movement wanted to preserve as much of the remaining old-growth forests as possible, and an opposing social movement supported a continued ‘sustainable’ logging of the forests for hardwood products. This research project undertook a comparative case study analysis of Australia (TCA) on the pro-logging side and Liberals For Forests (LFF) on the anti-logging side. It drew on a macro-level European theoretical approach (New Social Movement theory) and a US organizational approach (Resource Mobilisation Theory). The study also investigated the extent to which these two social movement organisations (SMOs) had been effective in Over the past 30 years in Western Australia (WA), there has been a heated debate about the future use of the remaining temperate old-growth forests of karri and jarrah in the south-west of the State. This debate revolved around policy proposals from two social movements: one social movement wanted to preserve as much of the remaining old-growth forests as possible, and an opposing social movement supported a continued ‘sustainable’ logging of the forests for hardwood products. This research project undertook a comparative case study analysis of one WA organisation from each of these two social movements- Timber Communities Australia (TCA) on the pro-logging side and Liberals For Forests (LFF) on the anti-logging side. It drew on a macro-level European theoretical approach (New Social Movement theory) and a US organizational approach (Resource Mobilisation Theory). The study also investigated the extent to which these two social movement organisations (SMOs) had been effective in influencing the development of State forest policy. For this purpose Schumaker’s (1975) framework for judging the political effectiveness of social movements was used. The key research problem investigated in this thesis is why these two SMOs continued to debate the forest policy issue after more than 30 years of public controversy? Interviews with a key range of stakeholders were the key research method of this study. Additionally, an investigation into important economic and social changes in the south west was undertaken using census and other data between 1971 and 2001 and this was supported by an historical analysis of the timber industry in WA’s south west. Finally, a 3-year study of the reporting of forest issues by two local and one national newspaper was completed. The 1998-2000 period was chosen for the newspaper analysis as this was when the new Regional Forest Agreement was being finalised. This research shows that new values toward the old-growth forests developed among the WA public over the past 30 years and this has created an unbridgeable policy gap between those such as the TCA who wanted the past policies to continue and those such as the LFF who wanted to preserve the remaining native forests. ABS data confirm that the south-west region of WA changed dramatically between 1970 and 2000 as the wine and tourism industries developed and that these changes were different to those occurring in the other wine regions and non-city areas of Australia. As the population increased in this region, a key segment attracted by these new employment opportunities were middle class, well-educated people with new values toward the natural environment. The interview and newspaper article data clearly showed that the debate in WA in the late 1990s over the proposed RFA provided a new political opportunity for the anti-logging movement to raise their concerns and to establish a renewed public debate about the appropriateness of the WA forest policies. This came at a time when the traditional policy power of the timber industry stakeholders and the government department in charge of the forests (Conservation And Land Management) had been dramatically diminished. The combination of these factors led to the election of the new ALP government and the introduction of a new, non-logging policy for WA’s old-growth native forests.

This research analyses the governance structures and processes of thirteen independent primary schools in Perth, and one state primary school in Western Australia termed an ‘alternative’ or ‘lighthouse’ school. More in-depth case studies were undertaken at five sites with participants from different time periods. All the schools had a school council or board since their foundations and notably all schools had their origins in the period of the alternative school and community empowerment movement of the 1970s and 1980s. In an era of market reform and the corporatisation of schools, the critical areas of focus for this research were: how community expectations and school identity were maintained within council-governed schools; how democratic imperatives compete with professionalism and school improvement issues; and how schools confront dilemmas of governance. Three frameworks, Phases of Development, Community Empowerment and Dilemmas, were employed as useful means to discuss school governance. The results revealed changes in governance over time. Schools began to envisage themselves less as communities and more as businesses. The emphasis was away from parent involvement and towards efficiency and commercial practices. Tensions and dilemmas arose out of these changes. The thesis concluded that it was not the structures or individuals that were crucial in governance processes but the playing out of particular tensions and dilemmas. Principals and councils have to acknowledge the dilemmas that arise from competing values systems and make choices based on a clear understanding of these dilemmas.

The major aim of this study was to develop a conceptual model representing the implementation process of a curriculum change occurring in a State Education Department region. This development had its genesis in the now extensive body of literature related to the organizational phenomenon of planned change. Since its early development in the 1960ts, the study of planned change occurring i n organizations has grown in sophistication, encompassing a steadily evolving number of theoretical constructs. Such a construct, of recent origin, was that of perceiving implementation of the innovation as a discrete process within the total planned change process. Although stillinits infancy, this concept has attracted a steadily growing body of research, The present study co-ordi nated some of these findings to form the basis for a four-stage model representing the implementation process under a special set of circumstances. The application of the model was tested under field conditions. A longitudinal case study design was adopted because this was ideally suited to test the assumption of implementationas a process. The design was divided in to four sections : concepts related to the decision to change; concepts related to the effect the rationale for implementation had on teachers' behaviour; concepts related to the sequence of involvement of implementers; and finally, concepts related to the measurementof the degree of implementation for teachers and pupils. Field work was applied inarural educational region of the State of Western Australia. This region was established in 1979 as part of an Australia-wide trend. I t is well documented that at the commencement of the 19701s, Austral ian governmentcontrol led education systems were highly centralized. By the beginning of the 1980ts, all were facing major change, each incorporating some form of decentral ization. In Western Australia, a shift in power from central authorities to Regional Superintendents occurred. With the increase i n power, the Regions received more duties and became more complex organizations. To meet the demand of testing a complex theoretical model in the intricate field setting of a State Education Department region, a wide range of data-gathering techniques was used. Questionnaires were employed, some specifically designed to suit this study and some selected from other research. The breadth and depth of the data collected was extended by the use of interviews, both focused and unstructured. Information from a wide variety of perspectives was gathered by using direct observation. This was applied to the testing of the theoretical model and also used to validate data drawn from other sources. Content analysis techniques were also used to triangulate the findings from questionnaire and interview techniques. The findings of the analysis of the data,within a matrix of hypotheses and sub-hypotheses, provided powerful statistical evidence indicating that the innovation was judged as being implemented by the teachers and the pupils. Data collected were also analysed as part of the research plan incorporating four major hypotheses and twenty six sub-sections. Each sub-section has been investigated empirically. This strategy was used to test the applicability of the conceptual model as a technique to represent the process of implementation followed by an innovation in Oral English introduced into a rural region of a State Education Department. The model proved to be a very effective device, aiding in the comprehension of an implementation process that occurred under the particular conditions described in the thesis.

The past three decades has been a period of intense and sustained debate in a number of major Western countries about the wisdom of police continuing to apply legislation which can severely punish offenders by fines and even imprisonment because of laws and policies that prohibit the use, possession and cultivation of cannabis. The large and growing number of young adults who have been exposed to the drug, some of whom have been charged and received criminal convictions with attendant deleterious effects on their employment and wellbeing, has forced policy makers to re-evaluate the justification for continuing to criminalise cannabis. This thesis examines in detail the law reforms that occurred in early 2004 with respect to cannabis offenders in Western Australia (WA) and the United Kingdom (UK) and what lessons these reforms may hold for other jurisdictions interested in decriminalisation of minor cannabis offences. A study was undertaken to compare the shortcomings and advantages of the different approaches to reform followed in WA and the UK. Reference to the reform in the UK, will be confined to meaning England, Wales and Northern Ireland as the necessary administrative guidelines have not so far been issued for Scotland. In WA the reforms required a substantial legislative effort to establish a complex framework that outlined in detail the circumstances when police may issue cannabis infringement notices (CINs), whereas in the UK the approach involved limited legislative activity by the reclassification of the legal status of cannabis and by providing police with administrative guidelines issued by the Association of Chief Police Commissioners as to how to exercise their discretion in issuing formal warnings for a minor cannabis offence. A comparison is made with New Zealand (NZ), where in spite of there being a similar process of deliberation and consultation as in WA and the UK, the government refused to implement formal reform because of a perception it was unable to decriminalise minor cannabis offences because of the restrictions imposed of agreement between the Clarke Labour Government and a minor political party. The example of the failure of government in NZ to achieve reform illustrates the importance that in some jurisdictions there will be a significant role for non parliamentary advisory bodies and lobby groups to argue for reform and to garner public support when reform has stalled or been frustrated. The thesis also includes a preliminary exploratory study using a number of indicators, such as prevalence and conviction data, to determine if the reforms implemented by the CIN scheme have resulted in or are likely to create unanticipated harms and to explore some of the issues in being to determine whether changes in law enforcement practices and priorities have impacted on the cannabis market or are likely to change the way cannabis may be transacted in WA.

Parental provisioning was investigated in two congeneric shearwater species, the winter breeding Little Shearwater Puffinus assimilis tunneyi and summer breeding Wedge-tailed Shearwater Puffinus pacificus. The Western Australian coast is characterised by climatic and oceanographic instability largely linked to the variable flow rate of the Leeuwin Current generated by differences in global climatic conditions. Ongoing long-term studies at the Western Australian coast have indicated that this climate driven phenomenon affects seabird reproductive participation and success. Such an ongoing, parallel study of Wedge-tailed Shearwater reproduction effectively provided this thesis with a background index of oceanographic conditions, or a context in which to view and interpret the ability of adults to provide parental care to the dependent nestling. Such an index of oceanographic conditions is generally lacking in studies of seabird provisioning. Fortuitously, this study was conducted in what appeared to be a favourable year (2000), a transition year (2001) and a less favourable year (2002) for seabird reproduction off the Western Australian coast. Consequently, it was possible to comment on the effectiveness of parental provisioning during different oceanographic conditions. In this thesis, parental provisioning encompassed the delivery of a range of resources to the dependent nestling, including a burrow, heat during incubation, protection from predators, brooding after hatching, and the delivery of food to sustain growth and development. The main focus of the study was the nestling feeding stage, although other more sensitive and less flexible phases were investigated in the Little Shearwater. Most research focused on the winter breeding Little Shearwater, as the species least studied. Adult Little Shearwaters were present at the nest throughout the night during the nestling feeding period, which presented the opportunity to examine provisioning from an adult perspective. Adult responses are discussed in the context of this index of oceanographic condition, in terms of regional food resources levels, and also more localised weather patterns which facilitate shearwater locomotion. A potential two-tier adult state-dependent mechanism of parental resource allocation is presented, which would allow a mobile K-strategist, foraging within an acceptable distance from the breeding colony, to persist in this relatively unstable and unpredictable environment. This research suggests that parents’ adjusted parental provisioning in order to minimise risks to the functional adult, which had attained its reproductive potential at the expense of the nestling that may or may not attain reproductive status. The weights of adult encountered at the colony did not differ significantly between different phases of the breeding season (pre-laying, incubation and nestling feeding) or between years. It appeared as if the weights of adults engaged in parental provision fluctuated within an acceptable “working” range whilst present at the colony, which makes it difficult to define average adult weights. The theory of threshold adult body condition suggests that only adults above a sufficient body condition are allocating resources towards reproduction, and therefore present at the breeding colony. Whilst, adults below a threshold are expected to be absent from the colony and therefore not willing to allocate resources to support the dependent nestling. In the two-tier adult state dependent allocation of parental care, firstly the body condition of the adult will determine if it is present at the colony, hence providing care for the offspring. Secondly if the adult is able to maintain adult body condition provisioning can be reactive to the needs (or body condition) of the nestling. Evidently, such a system of parental provisioning predominantly based on the ability to maintain adult body condition will be affected by differences in oceanographic and climatic conditions, which affect the ability of adults to maintain or replenish body condition within an acceptable time and distance away from the colony. The level and continuity of parental care provided by the pair will be discussed, especially how deviations from an optimal provisioning schedule may affect nestling growth, survival and viability. Ongoing, long term research of summer breeding Wedge-tailed Shearwaters along the Western Australian coast suggests that reproduction is adversely affected by prevailing negative southern oscillation indices and associated declines in the flow rate of the warm, low density Leeuwin Current. Despite breeding in the austral winter when the maximal flow rates of the Leeuwin Current are expected, Little Shearwater reproduction was also affected in a manner similar to that documented for tropical seabirds breeding in summer. Furthermore, decreases in productivity registered by local fisheries suggested that observed declines in seabird reproduction may be linked to an overall crash in productivity experienced along the Western Australian coast during years of weak Leeuwin Current flow. Such years are associated with more uniform and cold offshore water temperatures. Consequently, a regional lack of oceanographic resources, within an acceptable distance of the breeding site, are likely to adversely affect the ability of adults to replenish body condition, however other factors such as prevailing weather are also likely to affect energy expenditure during travel and foraging. Both factors would affect the ability of adults’ to maintain body conditions. In a favourable year, Little Shearwaters were able to meet nestling needs and the amount of food delivered matched the pattern of weight gain typical for Procellariiform young. Conversely, in a less favourable year, Little Shearwaters delivered food to young less often and the amount delivered was erratic, as the percentage of nestlings fed was consistently lower and temporal delivery was more irregular in the less favourable year. Nonetheless, food delivery also changed with nestling age, following a pattern similar to a favourable year, but at a lower rate. Future research should focus on the level of obesity attained by cohorts under different conditions and possibly the quality of feathers produced by nestlings. Feather quality and the state of obesity attained may affect the post-fledging buffer and ultimately affect fledging survival. Supplementary feeding suggested that adult Wedge-tailed Shearwaters adjusted feeding in response to proximal needs of nestlings, as supplementary fed nestlings were fed less than non-supplementary fed nestling. Furthermore, in both species adults changed provisioning to meet the changing needs of nestlings throughout ontogeny however the adult’s ability to respond to changing needs may be dependent upon the body condition of the adult and therefore ultimately dictated by resource availability. These results are in accord with other studies in which adults have altered provisioning in response to changing nestling needs. Whilst in other studies adults displayed an inability to react to nestling needs, which may have been linked to the difficulty faced by adult to maintain their own body condition during a less favourable year. The tentative mechanism of parental provisioning may help to explain the often contradictory outcomes recorded in studies of parental provisioning conducted in the absence of an indicator of resources availability and context in which to interpret adult response. Since, adults adjusted provisioning to firstly match their ability to maintain their own body condition in response to oceanographic conditions and secondly if able to met their own needs, in accordance with nestling needs. Therefore, parental provisioning is a flexible, state-dependent behaviour ultimately limited by oceanographic conditions. Once nestlings have hatched and passed a critical weight, they are more likely to survive and parental provisioning has the potential to become a highly flexible behaviour as the offspring can absorb periods of reduced parental provisioning. This relatively “forgiving” nestling phase is often targeted by studies of parental provisioning. Here, an optimal provisioning schedule may be orchestrated under favourable conditions however deviations may be absorbed without terminating the investment in reproduction. Although breeding at different times of the year, both species fed their nestling to a stage of obesity. This occurred, despite feeding nestlings near daily, which should have allowed adults to obtain regular feedback about the body condition of the nestling. Obesity may reflect the relatively unpredictable availability of resources along the Western Australian coast. However, adults may aim to increase the potential fitness of the nestling when adult body condition allows, through the provision of a post fledging buffer in terms of stored energy and high quality, structurally sound plumage. At the Western Australian coast, Little Shearwaters used a bimodal strategy to care for nestlings during incubation and feeding. Adults lost weight during periods of intensive provisioning, namely incubation and nestling feeding, but if too much weight was lost, provisioning was withheld and adults departed for a longer absence. Whilst absent from the colony for a prolonged period of time adults gained weight, both during the incubation and nestling feeding period. Return of birds from long absences appeared to be related to the predictable passage of weather systems. In Little Shearwater, during incubation the efforts of both parents were highly coordinated in a favourable year, since egg neglect was low, presumably as a consequence of predation pressure. Weather appeared to assist in the arrival of the relieving adult during incubation. Similarly during the transition to nestling feeding, the nocturnal activity at the breeding site indicated that the return of adults from long absences was associated with predictable changes in wind direction, related to the inevitable passage of weather systems, rather than wind strength, which is directly proportional to pressure differences between adjacent weather systems. In a favourable year, during nestling feeding the co-ordination of change overs between individuals within a pair also appeared to be high. Consequently, patterns of provisioning may be entrained throughout the duration of the breeding season, including incubation and nestling feeding, by an underlying pattern generated by the predictable passage of weather systems. Adults able to meet their own needs in a time frame dictated by the movement of weather system may minimise travel costs, whilst returning in time to allow the partner to depart to meet its needs. Both partners are required for the co-ordination of parental care to produce an optimal provisioning schedule. Consequently, activities are expected to be structured to protect not only the body condition of the self, but also of the partner in a species where biparental care is generally required to successfully raise an offspring. During nestling feeding, in a favourable year the co-ordinated bimodal strategy achieved near daily delivery of food, whilst in a less favourable year deviations from this pattern occurred, as adults spent more time at sea. The average duration of long absences, used to replenish body condition, appeared to increase during less favourable years. Further research should focus on variations in temporal absences and adult weights under different conditions that affect the ability of adults to replenish their body conditions. Furthermore, not all pairs were able to achieve daily food delivery during each year, and during a less favourable year a larger proportion of the breeding population appeared to be unable to deliver continuous parental care. Consequently, a larger proportion of nestlings remained unfed. The disruption in the input system, or deviations from a potentially optimal provisioning schedule, resulted in differences in growth rates between years. Costs incurred by adults during less favourable conditions appeared to be passed on to the nestling, whilst the risks to the functional adult that had reached reproductive potential were minimised. Wedge-tailed Shearwaters, breeding during the austral summer in a favourable year, were able to meet nestling needs. Here, food was delivered at a pattern that matched weight gain, where total overnight food delivered changed with nestling age, as in the Little Shearwaters. Wedge-tailed Shearwaters did not deliver food as regularly as Little Shearwaters. The colony of Wedge-tailed Shearwaters appeared to experience periods of reduced provisioning, during low wind conditions associated with dissipating tropical lows. During such conditions, Wedge-tailed Shearwater adults were often seen rafting at sea away from the breeding site suggesting it was energy expensive to fly. Such periods of poor provisioning associated with low wind speeds were recorded at different latitudes along the Western Australian coast and in different years. Dissipating tropical lows which generate low wind conditions are a seasonal occurrence however the frequency, persistence and intensity of such tropical lows appeared to fluctuate with offshore sea surface temperatures, frequency of tropical cyclones to the north and ultimately prevailing large scale climatic conditions that affect seas surface temperatures. Consequently, prevailing short term weather conditions which are affected by large scale climatic events, including climate change, have the potential to influence Wedge-tailed Shearwater reproduction. Wedge-tailed Shearwater nestlings supplementarily fed during a dissipating tropical low were visited and fed less than unfed nestlings of lower body condition. This implies that adults adjusted provisioning in accordance with nestling body condition. However, nestlings that had not been supplementarily fed were visited less often once conditions improved, suggesting that parents were unable to sustain food delivery. Parents of supplementarily fed nestlings, which had reduced provisioning during the adverse conditions, were able to feed their nestlings at a higher rate once conditions recovered then parents with non-supplementary fed nestlings. Thus, parents appeared to adjust provisioning in relation to nestling body condition however the ability of adults to maintain high levels of parental care appears to be limited, possibly by parental body condition. Similarly, adults reacted to the changing needs of a nestling throughout ontogeny in a favourable year, whilst during an adverse year deviation from a more optimal pattern of provisioning was evident. Meal sizes delivered by different species are often compared. However, food delivery appears to be adjusted with nestling age and differences in oceanographic conditions. Consequently, an optimal amount of food matching the developmental needs of the nestling may be met during optimal conditions using an optimal pattern of provisioning, whilst deviations from this may give an index of parental inability to cope with long or short-term deterioration in oceanic conditions, which ultimately affect their ability to meet adult needs. Furthermore, meal sizes are often determined during frequent weighing research of short duration, which is easily affected by proximal conditions that could affect the ability of adults to travel and would reflect the developmental stage of the nestling. Therefore, for meal sizes quoted it is not know if adults were able to engage in an optimal provisioning schedule or if deviations occur to compensate for below optimal conditions. Comparison of meal size by weight alone may not be feasible, even throughout a season within a species, as a seasonal shift in diet was recorded for Wedge-tailed Shearwaters during the breeding season using stable isotope. The different diets of different species often living in different geographic locations and the ability of some species to produce stomach oil, further confounds the ability to compare meal sizes by weight alone. It appears difficult to define a meal size characteristic for a species and make direct comparisons based on weight alone a practice widespread in seabird research. At best an optimal meal size for a given developmental stage may be used in conjunction with calorific values to calculate an optimal energy input for a specific age to compare between species. The seasonal difference in diet recorded during the Wedge-tailed Shearwater breeding season revealed a shift from a higher to a lower trophic level. This is consistent with females engaging in a pre-laying exodus where preferred resources may be targeted, whilst during nestling feeding foraging constraints are introduced as foraging occurs around a central location. A broader range of prey may be targeted within an acceptable distance from the breeding colony, including scavenging behind Western Rock Lobster fishing vessels which provide a predictable source of food – or discarded often imported bait. The application of stable isotope analysis provided promising insights into shearwater foraging behaviour otherwise difficult to elucidate. Different resources were targeted by the two species during egg membrane formation. Wedge-tailed Shearwaters generally appeared to forage at a higher trophic level than Little Shearwaters, although outliers suggest that Little Shearwaters also have the potential to target higher trophic levels. Differences in diet during egg formation were evident between different colonies of Wedge-tailed Shearwaters breeding at different locations. Consequently, stable isotope analysis may be used to track changes in diet between favourable and less favourable years, where increased foraging constraints are expected to emerge. Stable isotope analysis is a promising technique and interpretation of data will increase with further understanding of ecosystem dynamics and the development of a reference library. Direct observation at sea suggested that Little Shearwaters forage in deep, offshore in areas most likely influenced by the Leeuwin Current. They were not observed to forage in the cooler, inshore waters fed by a northwards flowing counter current, on the continental shelf between the Houtman Abrolhos Islands and the mainland. Maximum depth gauges revealed a maximal dive depth of approximately 34 m. The maximal dive depths recorded appeared to increases with time spent at sea, as indicated by birds engaged in short absences (near daily returns) from the colony and long absences (approximately weekly returns) when they were replenishing body condition. Long absences were recorded after an incubation shift or a period of daily nestling feeding. To summarise, a tentative mechanism of adult state-dependent allocation of parental provisioning in which pelagic seabirds persist in environments of fluctuating resource levels was proposed. This may be based upon the ability of adults to operate above a threshold body condition, which is ultimately dictated by resource availability and proximal conditions which affect the ability of adults to maintain their own body condition. Once adults struggle to maintain their body condition, a disruption in the co-ordination of the parental care orchestrated between the members of a pair can arise, as adults spend more time away from the colony replenishing their body condition. This results in a deviation from an optimal provisioning schedule, which is achievable in favourable years when resource levels and proximal conditions facilitate easy maintenance of the pair’s body condition. In this system, any costs incurred whilst struggling to replenish or maintain adult body condition are passed on to the nestling. In a system where biparental care is necessary, incentive exists for one partner to also act in a manner that facilitates the protection of the body condition of the other partner. The nestling in turn may absorb such deviations from an optimal provisioning schedule in a manner that affects the development of temporary attributes, rather than fixed morphological attributes. This may be a testimony of the strong selective forces exerted by the ocean, which also discourages sexual dimorphism in pelagic seabirds. Reduced levels of provisioning recorded in less favourable years translated into lower average peak weights, smaller growth rates and however asymptotes reached generally did not differ significantly between years. However, the deviation from the optimal provisioning schedule during less favourable years may reduce the fitness of the fledgling, through a reduction in the post fledging buffer, including investment in a smaller post fledging fat deposits and decreased plumage quality. It is possible, that nestling shunt costs incurred away from skeletal or fixed attributes. The nestling once independent may overcome lower quality plumage and a smaller post fledging fat buffer, if conditions are favourable. Thereby, the offspring engages in its own risk minimisation strategy and makes the most of its only chance for survival. Within a species, temporal patterns of parent provisioning and consequently foraging strategies are flexible. Firstly, a species may engage in a different foraging strategy ranging from unimodal to bimodal in response to prevailing conditions at a given location that affect the ability of adults to maintain their own body condition. Consequently, even at the same location under different conditions a shift in foraging strategy may result. Secondly, an optimal provisioning schedule able to meet the needs of the nestling may only be realised during favourable conditions when a pair is able to co-ordinate their efforts. The proportion of the colony able to achieve optimal provision is expected to vary between years and resource availability, as does the proportion of the breeding population able to return to the colony and lay an egg. Consequently, nestling quality of the cohort may be affected by the adult state dependent input system, based upon adult risk minimisation. This has implications for climate change, which affects sea surface temperatures and consequently oceanographic productivity and prevailing weather patterns. Effectively, costs are passed on to the offspring whilst the reproductive potential of the adult or pair is maintained. Such flexibility allows iteroparous k-strategists, such as shearwaters, to persist successfully in areas of climatic and oceanographic variability, but may have implications on the post-fledging survival chances. In an adverse year, despite reaching lower average weights, a proportion of adults were still able to feed their nestlings to obesity, possibly highlighting differences in quality between pairs. Since the state of obesity reached and the quality of feather produced may translate into increased post-fledging survival chances for the nestling, the survival chances of nestlings produced by a breeding population may not be equal, as the level of parental care delivered may vary between pairs and years. The subtle adjustments in two tier adult state-dependent system of parental provisioning may alter the post-fledging survival chances of the cohort and this has implications on population dynamics in terms of climate change, which reach beyond easily observed reductions in breeding participation and success.

Thesis (Ph.D.)--Murdoch University, 2008. / Thesis submitted to the Faculty of Health Sciences. Includes bibliographical references (leaves 208-233)

[Truncated abstract] Generally hydrologic and ecologic models operate on arbitrary time and space scales, selected by the model developer or user based on the availability of field data. In reality rainfall is highly variable not only annually, seasonally and monthly but also the intensities within a rainfall event and infiltration properties on semi-arid hillslopes can also be highly variable as a result of discontinuous vegetation cover that form mosaics of areas with vegetation and areas of bare soil. This thesis is directed at improving our understanding of the impacts of the temporal representation of rainfall and spatial heterogeneity on model predictions of hydrologic thresholds and surface runoff coefficients on semi-arid landscapes at the point and hillslope scales. We firstly quantified within storm rainfall variability across a climate gradient in Western Australia by parameterizing the bounded random cascade rainfall model with one minute rainfall from 15 locations across Western Australia. This study revealed that rainfall activity generated in the tropics had more within storm variability and a larger proportion of the storm events received the majority of rain in the first half of the event. Rainfall generated from fontal activity in the south was less variable and more evenly distributed throughout the event. Parameters from the rainfall analysis were then used as inputs into a conceptual point scale surface runoff model to investigate the sensitivity of point scale surface runoff thresholds to the resolution of rainfall inputs. This study related maximum infiltration capacities to average storm intensities (k*) and showed where model predictions of infiltration excess were most sensitive to rainfall resolution (ln k* = 0.4) and where using time averaged rainfall data can lead to an under prediction of infiltration excess and an over prediction of the amount of water entering the soil (ln k* > 2). For soils susceptible to both infiltration excess and saturation excess, total runoff sensitivity was scaled by relating drainage coefficients to average storm intensities (g*) and parameter ranges where predicted runoff was dominated by infiltration excess or saturation excess depending on the resolution of rainfall data were determined (ln g* <2). The sensitivity of surface runoff predictions and the influence of specific within storm properties were then analysed on the hillslope scale. '...' It was found that using the flow model we still get threshold behaviour in surface runoff. Where conditions produce slow surface runoff velocities, spatial heterogeneity and temporal heterogeneity influences hillslope surface runoff amounts. Where conditions create higher surface runoff velocities, the temporal structure of within storm intensities has a larger influence on runoff amounts than spatial heterogeneity. Our results show that a general understanding of the prevailing rainfall conditions and the soil's infiltration capacity can help in deciding whether high rainfall resolutions (below 1 h) are required for accurate surface runoff predictions. The results of this study can be considered a contribution to understanding the way within storm properties effect the processes on the hillslope under a range of overall storm, slope and infiltration conditions as well as an improved understanding of how different vegetation patterns function to trap runoff at different total vegetation covers and rainfall intensities.