[Truncated abstract] Currently, Alcoa World Alumina Australia (Alcoa) mines and undertakes procedures to rehabilitate approximately 550 ha of jarrah forest each year at two open-cut bauxite mines in South-West Western Australia. Alcoa aims to establish a self-sustaining jarrah forest ecosystem that maintains the functions of the landscape prior to mining, including biodiversity, on areas that have been mined for bauxite. Indigenous terrestrial orchids form a significant proportion of the indigenous geophytic plant species that either fail to colonise rehabilitated areas or do so very slowly. Terrestrial orchids are considered to be particularly sensitive to competition from weeds and disturbance, which combined with the obligate nature of the orchid-mycorrhizal fungus association suggests that orchids would colonise rehabilitation areas only when both microhabitat sites and soil microflora have established. Occurrence of certain orchids may therefore be expected to be useful as indicators of ecosystem health, the success of vegetation establishment and the recovery of edaphic conditions suitable for orchid mycorrhizal fungi. Vegetation surveys were undertaken to compare orchid species richness and population size of a chrono-sequence of rehabilitation areas with adjacent unmined forest. ... Orchid taxa present in each vegetation assemblage were generally not exclusive to these assemblages, with the following broad exclusions: D. bracteata was found only in species assemblages associated with rehabilitation areas; and Eriochilus sp. and T. crinita were found only in species assemblages associated with unmined forest. No single orchid species appears to be an indicator of ecosystem recovery. However, the presence of populations of C. flava, P. sp. crinkled leaf (G.J.Keighery 13426) or P. recurva in combination with the absence of the disturbance opportunist orchid taxa D. bracteata and M. media appears to be a measure of the maturity of the rehabilitation vegetation. Orchid species richness and clonal orchid population size were correlated with changes in vegetation structure, but apart from the absence of orchids in 1 year old rehabilitation areas, these orchid population characteristics did not show any direct relationship with rehabilitation age or vegetation maturity. Only two orchid taxa appeared to have potential as indicators of vegetation characteristics: T. crinita as an indicator of undisturbed jarrah forest; and D. bracteata as an indicator of disturbed ecosystems. The results of this study suggest that most jarrah forest orchid taxa will readily colonise the post bauxite mining landscape, but that the unassisted colonisation by recalcitrant orchid taxa may be a prolonged process. It is recommended that field-based transplantation and/or seeding trials be undertaken with these recalcitrant taxa to determine if these procedures will enhance recruitment. The results of this work have applications not only in the management of post-mining landscapes but also in vegetation monitoring and conservation work in Western Australia and elsewhere.

[Truncated abstract] In an era of emerging and resurging infectious diseases, understanding the ecological processes that influence pathogen activity and the influences of anthropogenic change to those are critical. Ross River virus (RRV, Togoviridae: Alphavirus) is a mosquito-borne zoonosis occurring in Australia with a significant human disease burden. In the southwest of Western Australia (WA) RRV is principally vectored by Aedes camptorhynchus Thomson (Diptera: Culicidae), which is halophilic. The inland southwest, the Wheatbelt region, of WA is substantially affected by an anthropogenic salinisation of agricultural land called dryland salinity, which threatens to influence transmission of this arbovirus. This study assessed the ecological impacts of dryland salinity on mosquitoes, mammalian hosts and their interactions to influence the potential for RRV transmission. Many aquatic insect taxa colonise ephemeral water bodies directly as adults or by oviposition. Using a manipulative experiment and sampling from ephemeral water bodies in the Wheatbelt, I demonstrated that salinity of water bodies can modify colonisation behaviour and the distribution of some organisms across the landscape. Halosensitive fauna selected less saline mesocosms for oviposition and colonisation. In particular, Culex australicus Dobrotworksy and Drummond and Anopheles annulipes Giles (Diptera: Culicidae), potential competitors with Ae. camptorhynchus, avoided ovipostion in saline mesocosms and water bodies in the field. This finding suggests salinity influences behaviour and may reduce interspecific interactions between these taxa and Ae. camptorhynchus at higher salinities. Using extensive field surveys of ephemeral water bodies in the Wheatbelt I found mosquitoes frequently colonised ephemeral water bodies, responded positively to rainfall, and populated smaller water bodies more densely than larger water bodies. The habitat characteristics of ephemeral water bodies changed in association with salinity. Consequently there were both direct and indirect associations between salinity and colonising mosquitoes. Ultimately the structure of mosquito assemblages changed with increasing salinity, favouring an increased regional distribution and abundance of Ae. camptorhynchus. The direct implication of this result is secondary salinisation has enhanced the vectorial potential for RRV transmission in the WA Wheatbelt. ... This thesis contributes to an emerging body of research aimed at delineating important ecological processes which determine transmission of infections disease. Collectively the findings in this study suggest dryland salinity enhances the potential for RRV activity in the Wheatbelt. Currently, human RRV notifications in the Wheatbelt do not reflect the salinity-RRV transmission potential in that area, but appear to be associated with dispersal of RRV from the enzootic coastal zone of southwest WA. I speculate dryland salinity is a determinant of potential for RRV transmission, but not activity. Dryland salinity is predicted to undergo a two to four fold expansion by 2050, which will increase the regional potential for RRV activity. Preservation and restoration of freshwater ecosystems may ameliorate the potential for transmission of RRV and, possibly, human disease incidence.

Rhizanthella gardneri (Rogers) is a critically endangered orchid restricted to two isolated regions of south-western Australia. Rhizanthella gardneri is an entirely subterranean mycoheterotrophic species that purportedly forms a tripartite relationship with a mycorrhizal fungus (Ceratobasidiales) that links with an autotrophic shrub of the Melaleuca uncinata complex to acquire nutrients. Whether the rarity of R. gardneri is intrinsic is overshadowed by the recent effect of extrinsic factors that means R. gardneri requires some form of conservation and may also be a viable candidate for restoration. To create an integrated conservation strategy for R. gardneri, reasons for its decline and knowledge of its biological and ecological functioning must be elucidated. This thesis focuses on three key questions; 1) what are the habitat requirements and limitations to R. gardneri survival; 2) what is the identity and specificity of the fungus R. gardneri forms mycorrhizas with; and 3) does R. gardneri form a nutrient-sharing tripartite relationship with a mycorrhizal fungus and autotrophic shrub. Key climate, soil and vegetation characteristics of known R. gardneri habitats were quantified to provide baseline data for monitoring known R. gardneri populations, to better understand how R. gardneri interacts with its habitat, and to identify possible new sites for R. gardneri introduction. Habitats of the two known R. gardneri populations differed considerably in soil chemistry, Melaleuca structure and Melaleuca productivity. Individual sites within populations were relatively similar in all attributes measured while overall Northern and Southern habitats were distinct from each other. These results suggest that R. gardneri can tolerate a range of conditions and may be more widespread than previously thought, given that there are extensive areas of Melaleuca thickets with similar habitat characteristics across south-western Australia. The fungus forming mycorrhizas with R. gardneri was identified, using nuclear ribosomal DNA sequences, as a Rhizoctonia-type fungus within the Ceratobasidiales. All fungi isolated from R. gardneri individuals representative of its currently known distribution were genetically similar, suggesting R. gardneri is highly dependent on this specific fungal species. Given that R. gardneri appears to exclusively associate with a specific fungal species, species-specific molecular primers were designed and used to analyse the fungi’s presence in known and potential R. gardneri habitats. These results 6 suggest that the fungus exists beyond the known R. gardneri habitats and gives hope to finding new populations.

Rhizanthella gardneri (Rogers) is a critically endangered orchid restricted to two isolated regions of south-western Australia. Rhizanthella gardneri is an entirely subterranean mycoheterotrophic species that purportedly forms a tripartite relationship with a mycorrhizal fungus (Ceratobasidiales) that links with an autotrophic shrub of the Melaleuca uncinata complex to acquire nutrients. Whether the rarity of R. gardneri is intrinsic is overshadowed by the recent effect of extrinsic factors that means R. gardneri requires some form of conservation and may also be a viable candidate for restoration. To create an integrated conservation strategy for R. gardneri, reasons for its decline and knowledge of its biological and ecological functioning must be elucidated. This thesis focuses on three key questions; 1) what are the habitat requirements and limitations to R. gardneri survival; 2) what is the identity and specificity of the fungus R. gardneri forms mycorrhizas with; and 3) does R. gardneri form a nutrient-sharing tripartite relationship with a mycorrhizal fungus and autotrophic shrub. Key climate, soil and vegetation characteristics of known R. gardneri habitats were quantified to provide baseline data for monitoring known R. gardneri populations, to better understand how R. gardneri interacts with its habitat, and to identify possible new sites for R. gardneri introduction. Habitats of the two known R. gardneri populations differed considerably in soil chemistry, Melaleuca structure and Melaleuca productivity. Individual sites within populations were relatively similar in all attributes measured while overall Northern and Southern habitats were distinct from each other. These results suggest that R. gardneri can tolerate a range of conditions and may be more widespread than previously thought, given that there are extensive areas of Melaleuca thickets with similar habitat characteristics across south-western Australia. The fungus forming mycorrhizas with R. gardneri was identified, using nuclear ribosomal DNA sequences, as a Rhizoctonia-type fungus within the Ceratobasidiales. All fungi isolated from R. gardneri individuals representative of its currently known distribution were genetically similar, suggesting R. gardneri is highly dependent on this specific fungal species. Given that R. gardneri appears to exclusively associate with a specific fungal species, species-specific molecular primers were designed and used to analyse the fungi’s presence in known and potential R. gardneri habitats. These results 6 suggest that the fungus exists beyond the known R. gardneri habitats and gives hope to finding new populations.

[Truncated abstract] Indigenous Australians suffer cardiovascular disease (CVD) at a rate six times greater than the general population in Australia and while the incidence of CVD has been reduced dramatically amongst the majority of non-indigenous Australians and amongst Indigenous populations in other countries in the last 30 years, there has been little change in the figures for Aboriginal Australians, showing that heart health campaigns have little impact, for this group of people. Aims : The principal aims of this study were firstly, to determine and record the barriers to the development and delivery of CVD prevention programs amongst Indigenous Australians and secondly, to develop an alternative, effective and culturally sensitive method of delivering heart health messages. Methods and results : The study was qualitative research undertaken in three South-West towns of Western Australia where the incidence of CVD was high amongst the Aboriginal community members. The use of semi-formal interviews, informal individual consultation, observation, and focus groups were methods implemented to obtain information. The first phase of the research was to identify the barriers which affected the Aboriginal Health Workers’ ability to deliver specialist educational programs. Questionnaires and interviews with the Aboriginal Health Workers and other health professionals in the towns, and community focus groups were undertaken in this phase of the study. The second phase of the research was aimed at developing an alternative strategy for delivering heart health messages. The focus changed to adopt more traditional ways of passing on information in Indigenous communities. The idea of small gatherings of friends or family with a trusted community member presenting the health message was developed. The third phase of the research was to implement this new approach. Lay educators who had been identified within focus groups and by Aboriginal Health Workers were trained in each of the towns and a protocol involving discussions of health issues, viewing a video on CVD, produced by the National Heart Foundation, sharing in a ‘heart healthy’ lunch and partaking in a ‘heart health’ knowledge game which was developed specifically for the gatherings. Several of these gatherings were held in each of the towns and they became known as ‘HeartAware parties’.

[Truncated abstract] A functional ecosystem is increasingly being recognised as a requirement for health and well being of resident human populations. Clearing of native vegetation for agriculture has left 1.047 million hectares of south-west Western Australia affected by a severe form of environmental degradation, dryland salinity, characterised by secondary soil salinisation and waterlogging. This area may expand by a further 1.7-3.4 million hectares if current trends continue. Ecosystems in saline affected regions display many of the classic characteristics of Ecosystem Distress Syndrome (EDS). One outcome of EDS that has not yet been investigated in relation to dryland salinity is adverse human health implications. This thesis focuses on one such potential adverse health outcome: increased incidence of Ross River virus (RRV), the most common mosquito-borne disease in Australia. Spatial analysis of RRV notifications did not reveal a significant association with dryland salinity. To overcome inherent limitations with notification data, serological RRV antibody prevalence was also investigated, and again no significant association with dryland salinity was detected. However, the spatial scale imposed limited the sensitivity of both studies. ... This thesis represents the first attempt to prospectively investigate the influence of secondary soil salinity on mosquito-borne disease by combining entomological, environmental and epidemiological data. The evidence collected indicates that RRV disease incidence is not currently a significant population health priority in areas affected by dryland salinity despite the dominant presence of Ae. camptorhynchus. Potential limiting factors include; local climatic impact on the seasonal mosquito population dynamics; vertebrate host distribution and feeding behaviour of Ae. camptorhynchus; and the scarce and uneven human population distribution across the region. However, the potential for increased disease risk in dryland salinity affected areas to become apparent in the future cannot be discounted, particularly in light of the increasing extent predicted to develop over coming decades before any benefits of amelioration strategies are observed. Finally, it is important to note that both dryland salinity and salinity induced by irrigation are important forms of environmental degradation in arid and semi-arid worldwide, with a total population of over 400 million people. Potential health risks will of course vary widely across different regions depending on a range of factors specific to the local region and the complex interactions between them. It is therefore not possible to make broad generalisations. The need is highlighted for similar research in other regions and it is contended that an ecosystem health framework provides the necessary basis for such investigations.

[Truncated abstract. Please see the pdf format for the complete text. Also, formulae and special characters can only be approximated here. Please see the pdf version for an accurate reproduction.] This thesis examines the water use, ecophysiology and hydraulic architecture of Eucalyptus marginata (jarrah) growing on bauxite mine rehabilitation sites in the jarrah forest of south-western Australia. The principal objective was to characterise the key environment and plant-based influences on tree water use, and to better understand the dynamics of water use over a range of spatial and temporal scales in this drought-prone ecosystem. A novel sap flow measurement system (based on the use of the heat pulse method) was developed so that a large number of trees could be monitored concurrently in the field. A validation experiment using potted jarrah saplings showed that rates of sap flow (transpiration) obtained using this system agreed with those obtained gravimetrically. Notably, diurnal patterns of transpiration were measured accurately and with precision using the newly developed heat ratio method. Field studies showed that water stress and water use by jarrah saplings on rehabilitation sites were strongly seasonal: being greatest in summer when it was warm and dry, and least in winter when it was cool and wet. At different times, water use was influenced by soil water availability, vapour pressure deficit (VPD) and plant hydraulic conductance. In some areas, there was evidence of a rapid decline in transpiration in response to dry soil conditions. At the end of summer, most saplings on rehabilitation sites were not water stressed, whereas water status in the forest was poor for small saplings but improved with increasing size. It has been recognised that mature jarrah trees avoid drought by having deep root systems, however, it appears that saplings on rehabilitation sites may have not yet developed functional deep roots, and as such, they may be heavily reliant on moisture stored in surface soil horizons. Simple predictive models of tree water use revealed that stand water use was 74 % of annual rainfall at a high density (leaf area index, LAI = 3.1), high rainfall (1200 mm yr-1) site, and 12 % of rainfall at a low density (LAI = 0.4), low rainfall (600 mm yr-1) site, and that water use increased with stand growth. A controlled field experiment confirmed that: (1) sapling transpiration was restricted as root-zone water availability declined, irrespective of VPD; (2) transpiration was correlated with VPD when water was abundant; and (3) transpiration was limited by soil-to-leaf hydraulic conductance when water was abundant and VPD was high (> 2 kPa). Specifically, transpiration was regulated by stomatal conductance. Large stomatal apertures could sustain high transpiration rates, but stomata were sensitive to hydraulic perturbations caused by soil water deficits and/or high evaporative demand. No other physiological mechanisms conferred immediate resistance to drought. Empirical observations were agreeably linked with a current theory suggesting that stomata regulate transpiration and plant water potential in order to prevent hydraulic dysfunction following a reduction in soil-to-leaf hydraulic conductance. Moreover, it was clear that plant hydraulic capacity determined the pattern and extent of stomatal regulation. Differences in hydraulic capacity across a gradient in water availability were a reflection of differences in root-to-leaf hydraulic conductance, and were possibly related to differences in xylem structure. Saplings on rehabilitation sites had greater hydraulic conductance (by 50 %) and greater leaf-specific rates of transpiration at the high rainfall site (1.5 kg m-2 day1) than at the low rainfall site (0.8 kg m-2 day1) under near optimal conditions. Also, rehabilitation-grown saplings had significantly greater leaf area, leaf area to sapwood area ratios and hydraulic conductance (by 30-50 %) compared to forest-grown saplings, a strong indication that soils in rehabilitation sites contained more water than soils in the forest. Results suggested that: (1) the hydraulic structure and function of saplings growing under the same climatic conditions was determined by soil water availability; (2) drought reduced stomatal conductance and transpiration by reducing whole-tree hydraulic conductance; and (3) saplings growing on open rehabilitation sites utilised more abundant water, light and nutrients than saplings growing in the forest understorey. These findings support a paradigm that trees evolve hydraulic equipment and physiological characteristics suited to the most efficient use of water from a particular spatial and temporal niche in the soil environment.

[Truncated abstract] Kelp beds of South-Western Australia have high alpha (within habitat) diversity, through high species turnover at small spatial scales. The E. radiata canopy has a strong negative influence on the diversity of the understorey through intense interspecific competition for light. Literature suggests that when the competitively dominant species such as E. radiata are physically removed, diversity will increase, as less competitive species become more abundant. Apart from disturbance, evidence suggests that reef topography at the 1-10 m vertical scale also has an influence on the structure of the kelp beds, particularly in reference to relative abundance of canopy algae and species richness of the assemblage. In this thesis, I explore the role of algal assemblage recovery from physical disturbance to maintain high diversity. I also investigate the influence of reef structure (in terms of topography at the 1-10 m vertical scale) on assemblage recovery. This thesis provides a valuable functional explanation for the high diversity observed in South-Western algal assemblages. In addition, it explores the influence of reef topography which has received little attention to date . . . Overall, this thesis argues that the high alpha diversity in algal assemblages of South-Western Australia is due to local scale processes including disturbance and assemblage recovery which generate diversity by the creation of species rich gap states and by phase-shifts during the recovery process, creating a mosaic of different patch types. Assemblage recovery is composed of several processes, including survival of juvenile kelp sporophytes and canopy shading, added to macroalgal diversity through spatial and temporal variation in their outcomes. Reef topography contributed to algal diversity by influencing the processes associated with assemblage recovery through alteration of key physical variables including light levels and water motion.

While it is now well established that many Europeans were delighted with the landscapes they encountered in colonial Australia, the pioneer narrative that portrays colonists as threatened and alienated by a harsh environment and constantly engaged in battles with the land is still powerful in both scholarly and popular writing. This thesis challenges this dominant narrative and demonstrates that in a remarkably short period of time some colonists developed strong connections with, and even affection for, their 'new' place in Western Australia. Using archival materials for twenty-one colonists who settled in five regions across southern Western Australia from the 1830s to the early 1900s, here this complex process of belonging is unravelled and several key questions are posed: what lenses did the colonists utilise to view the land? How did they use and manage the land? How were issues of class, domesticity and gender roles negotiated in their 'new' environment? What connections did they make with the land? And ultimately, to what extent did they feel a sense of belonging in the Colony? I argue that although utilitarian approaches to the land are evident, this was not the only way colonists viewed the land; for example, they often used the picturesque to express delight and charm. Gender roles and ideas of class were modified as men, as well as women, worked in the home and planted flower gardens, and both men and women carried out tasks that in their households in England and Ireland, would have been done by servants. Thus, the demarcation of activities that were traditionally for men, women and servants became less distinct and amplified their connection to place. Boundaries between the colonists' domestic space and the wider environments also became more permeable as women ventured beyond their houses and gardens to explore and journey through the landscapes. The selected colonists had romantic ideas of nature and wilderness, that in the British middle and upper-middle class were associated with being removed from the land, but in colonial Western Australia many of them were intimately engaged with it. Through their interactions with the land and connections they made with their social networks, most of these colonists developed an attachment for their 'new' place and called it home; they belonged there.

Puccinellia (puccinellia ciliata) and tall wheatgrass (Thinopyrum ponticum) often show ecological zonation in saline landscapes, with puccinellia occurring in less elevated more saline/waterlogged locations, and tall wheatgrass occurring in more elevated less saline/waterlogged locations. The aims of this study were to: (a) characterize the observed ecological zonation at a field site, (b) quantify the effects of variables likely to explain growth differences of the two plants in glasshouse experiments, and (c) identify and compare anatomical and physiological mechanisms that explain these zonation patterns. At an experiment in the field near Kojonup (0522824E, 6244579N), puccinellia was found to colonise the lower more severely salinised and waterlogged zones of the landscape, with tall wheatgrass occupying the higher less affected zones. These differences in zonation were clearly associated with variance in soil salinity and water-table depth. Glasshouse experiments in soil revealed that low pH values, low calcium concentrations and variation in salinity alone did not explain the ecological zonation observed in the field. However, there was a substantial difference in the responses of the two plant species to waterlogging in combination with salinity. Puccinellia grew better under saline waterlogged conditions than tall wheatgrass, which was associated with better regulation of Na+ and K+ under saline/waterlogged conditions than in tall wheatgrass. Under non-saline conditions, waterlogging (hypoxia) decreased shoot weights in puccinellia by 15% and in tall wheatgrass by 20%. Similar growth results were obtained in nutrient solution culture, where waterlogging was simulated by lowering the oxygen in solutions through bubbling with N2 gas. Under saline hypoxic conditions, puccinellia, compared to tall wheatgrass, showed increased growth and maintenance of selectivity of K+ over Na+ across adventitious roots. Solution experiments revealed adaptive traits responsible for conveying better growth and ion maintenance present in puccinellia, but not tall wheatgrass, such as inducement of a barrier to radial oxygen loss in the basal regions of adventitious roots (not previously reported in the literature for puccinellia), formation of root aerenchyma and packing of cortical cells and suberin deposition in hypodermal and endodermal root cell layers. These results should assist in targeting pasture species, and predicting their growth response, in saline and waterlogged landscapes. Further work on examining the genetic material of puccinellia is warranted in order to identify genes that could be transferred into crop plants to convey salt and waterlogging tolerance.