Life Sciences Commons^™

Causes And Possible Consequences Of Hybridisation In Angelfishes At Christmas Island, Federico Vitelli

Theses: Doctorates and Masters

The angelfishes (family Pomacanthidae) have the greatest proportion (~30%) of hybridising species, compared to other families of reef fishes, with 26 species implicated in hybridisation. However, very little is known about hybridisation in angelfish, especially in terms of fitness of the hybrids and possible ecological consequences. Hybrids between three species (C. flavissima, C. eibli and C. vroliki) in the genus Centropyge have previously been reported from Christmas island, where these have been observed in heterospecific harems and interbreeding. This provides the unique opportunity to examine the breakdown in assortative mating in marine fishes. The broad aim of this …

Predicting The Impact Of Future Climate On Ecologically Important Macroalgae, Charlie Phelps

Theses: Doctorates and Masters

Macroalgae play an important role in coastal reef systems and are often referred to as ecosystem engineers. They serve as primary producers, supporting a diverse range of organisms, and are a sink for atmospheric CO2. Water acidification and ocean warming caused by anthropogenic activities are affecting many marine flora and fauna, potentially impacting the physical and chemical performance of macroalgae and the consumption rates of associated herbivores. Many studies have focused on ocean acidification or ocean warming individually but there is an overall lack of research investigating the combined effects and the ensuing repercussions on consumer-prey relationships.

Three species of …

Dynamics Of Baseline Stable Isotopes Within A Temperate Coastal Ecosystem: Relationships And Projections Using Physical And Biogeochemical Factors, Andrew Mackey

Theses: Doctorates and Masters

Measurements of carbon (13C/12C; δ13C) and nitrogen (15N/14N; δ15N) stable isotope ratios have become important tools for: estimating energy flow and trophic positions in aquatic foodwebs; comparing food webs; and aiding in the tracking of wide-ranging consumers. However, each of these applications requires accurate measurements of isotopic signatures in organisms at or near the base of the food web (e.g. autotrophs and their consumers), which act as basal reference points from which to calibrate inferences. Therefore, understanding variations in isotopic baselines, and the mechanisms leading to their variability, is crucial for food web ecology.

Using the shallow temperate reefs along …

Systematics And Biogeography Of The Australian Burrowing Freshwater Crayfish Genus Engaewa Riekk (Decapoda: Parastacidae), Quinton Burnham

Theses: Doctorates and Masters

The overall aim of this study was to explore the systematics and biogeographic patterns of the freshwater crayfish genus Engaewa Riek, a strongly burrowing freshwater crayfish restricted to the coastal corner of south-western Australia (SWA). The genus Engaewa is a Gondwanan relict with great potential as a marker of historical processes, due to its high habitat specificity and low dispersal ability. This study comprises an extensive taxonomic and phylogenetic revision of the genus Engaewa (using both molecular and morphological data), a detailed study of its distribution and uses the knowledge gained to explore biogeographic patterns in the biodiversity hotspot of …

Metapopulation Theory Explains Black-Stripe Minnow (Pisces: Galaxiidae, Galaxiella Nigrostriata) Distribution In Seasonal Wetlands In South-West Western Australia, David M. Galeotti

Theses: Doctorates and Masters

The objective of this project was to determine if Galaxiella nigrostriata populations could belong to a metapopulation. Metapopulation theory describes how multiple populations with occasional connectivity are a ‘population of populations’. Some populations’ habitats have optimal conditions (source habitats), others experience regular extinctions (sink habitats). Connectivity allows repopulation of extinct or uninhabited habitats. Galaxiella nigrostriata occurred randomly in 11 seasonal wetlands in the Kemerton wetland complex in south-west Western Australia over a 16 year period. The wetlands did not appear to be connected.

Around 70% of wetlands on the Swan Coastal Plain in south-west WA have been filled or degraded …

Food Resource Availability For Carnaby's Cockatoo Calyptorhynchus Latirostris On The Swan Coast Plain, Teagan Johnston

Theses: Doctorates and Masters

To achieve a balance between sustainable development and conservation of threatened species, management depends on understanding the predicted response and interaction of that species with their environment in order to develop appropriate mitigating solutions. The Carnaby’s cockatoo Calyptorhynchus latirostris is declining across much of its range due to the detrimental effect of habitat degradation and loss. Since the decline of food resource availability in non-breeding areas is believed to be contributing to the reduction in the number of Carnaby’s cockatoos knowledge of the birds’ foraging ecology and the influence of external factors on food resource availability is essential for effective …

Herbivory By Parma Mccullochi (Pomacentridae) : Its Role As An Ecosystem Engineer In Temperate Algal-Dominated Reefs, Frederico Vitelli

Theses: Doctorates and Masters

Pomacentridae is one of the most representative families of herbivorous fishes inhabiting both tropical and temperate reefs, yet the vast majority of studies examining feeding within this family have been undertaken in tropical rather than temperate regions. Despite the high abundances of the pomacentrid Parma mccullochi in temperate waters of Western Australia, and their likely importance in removing algae from reefs in the region, there is a lack of information on their diet and their impact on the reef algal community. This study aims to determine the role of Parma mccullochi as an ecosystem engineer on temperate algal-dominated reefs in …

The Biology And Ecology Of Epinephilidae Speciea And Their Implications To Fisheries Management, Jason R. How

Theses: Doctorates and Masters

This thesis examines the biological and ecological aspects of members of the globally exploited Epinephilidae with reference to fisheries management and in particular the use of closures. The leopard coralgrouper Plectropomus leopardus is a common reef fish throughout the Indo-Pacific region and a major target of both commercial and recreational fisheries. There has been limited research on this species in the eastern Indian Ocean, where there are only two populations. An examination of the species found a number of significant biological differences to their eastern Australian con-specifics. Most noticeable was the strong size-related cue over their protogynous sex change. The …

Applying The Principles Of Spatial Modelling To The Management Of Biodiversity In The Fragmented Landscapes Of South-Western Australia, Shaun Molloy

Theses: Doctorates and Masters

Biodiversity conservation throughout the world is challenged by the impacts of a changing climate on fragmented landscapes. To mitigate these threats, conservation managers require models which can demonstrate the consequences of both negative impacts and management actions. This need can be addressed through spatial modelling applications. Unfortunately, throughout much of the world, spatial modelling is forgone, being seen as requiring skills and resources beyond the means of many conservation planners and managers. This thesis seeks to address this dilemma by delivering criteria for a successful modelling application and by providing case studies which demonstrate how appropriate modelling can be undertaken …

The Impact Of Black Swan (Cygnus Atratus) Grazing On The Seagrass Halophila Ovalis In The Lower Swan River Estuary, Gary Choney

Theses: Doctorates and Masters

Grazing is an important ecosystem process, influencing community structure and rates of ecosystem processes. Although grazing on seagrasses is generally considered to be minor in many temperate regions of the world, waterfowl are often considered significant grazers in temperate lagoons and estuaries. This study examined spatial and temporal variation in swan abundance, grazing pressure and the impact grazing has on seagrass. Little is known on how grazing rates vary on larger water bodies in the southern hemisphere at different times of year and whether temporal changes in grazing rates affect the ability of seagrasses to tolerate grazing. The plant response …

Swamp : Walking The Wetlands Of The Swan Coastal Plain ; And With The Exegesis, A Walk In The Anthropocene: Homesickness And The Walker-Writer, Anandashila Saraswati

Theses: Doctorates and Masters

This project is comprised of a creative work and accompanying exegesis. The creative work is a collection of poetry which examines the history and ecology of the wetlands and river systems of the Swan Coastal Plain, and which utilises the practice of walking as a research methodology. For the creative practitioner walking reintroduces the body as a fundamental definer of experience, placing the investigation centrally in the corporeal self, using the physical senses as investigative tools of enquiry. As Rebecca Solnit comments in her history of walking, ‘exploring the world is one of the best ways of exploring the mind, …

Trophic Implications Of Light Reductions For Amphibolis Griffithii Seagrass Fauna, Adam Gartner

Theses: Doctorates and Masters

The ongoing threat of seagrass loss from reduced light availability, coupled with our lack of knowledge of associated trophic responses has motivated this characterization of the flow-on effects of light reductions to Amphibolis griffithii seagrass fauna. Recently, field manipulations of varying light reductions, induced disturbances in a A. griffithii seagrass meadow that have been shown to effect potential food resources and the structural complexity of seagrass habitats for macroinvertebrates. This offered the opportunity to assess the flow-on effects to seagrass for fauna, a topic that has seldom been examined. This study investigated the effects of different light reduction intensity (high: …

Reintroduction Ecology Of Mala (Lagorchestes Hirsutus) And Merrnine (Lagostrophus Fasciatus) At Shark Bay, Western Australia, Blair Hardman

Theses: Doctorates and Masters

The transfer of threatened animals from one location to another in order to benefit the species is a technique frequently used by animal conservation managers. However, very few of these relocations have experimentally assessed the relative merits and disadvantages of commonly used release techniques. Two species of hare-wallaby, mala (Lagorchestes hirsutus) and merrnine (Lagostrophus fasciatus), were reintroduced in August 2001 onto Peron Peninsula in Western Australia. These threatened species were reintroduced using two release strategies (soft versus hard release), and their subsequent movements and body condition were monitored using radio-telemetry and trapping.

Movement Patterns And Habitat Usage Of Shark Bay Dugongs, David K. Holley

Theses: Doctorates and Masters

In order to define small and large scale spatial and temporal individual movement patterns of dugongs (Dugong dugon) within the Shark Bay World Heritage Property (SBWHP) a total of 19 dugongs were fitted with remote location recording and transmitting devices. Combined locations from all units totalled over 10,000 locations. This spatial and temporal data was used to define movement patterns of dugongs within Shark Bay as well as areas of high use deemed to be indicative of foraging activity. Platform Transmitting Terminals (PTT?s) using the ARGOS location collection system tracked animals over large temporal scales with 4 animals tracked up …

The Ecology And Behaviour Of Varanus Mertensi (Reptilia: Varanidae), Phillip J. Mayes

Theses: Doctorates and Masters

This study examines numerous aspects of the ecology and behaviour of Merten's Water Monitor, Varanus mertensi (Reptilia: Varanidae) including; daily behaviour, diet, foraging behaviour, reproductive seasonality and daily and long-term movements. Findings from over two years of field study of V. mertensi found in waterbodies of both the Ord River Irrigation Scheme and surrounding East Kimberley/Victoria River Downs bioregion of Western Australia are presented. This study simultaneously broadens our understanding of the family Varanidae and provides insight into the life of a semi-aquatic faunal species found in waterbodies of the Ord River Irrigation Scheme.

The Influence Of Seabird-Derived Nutrients On Island Ecosystems In The Oligotrophic Marine Waters Of South-Western Australia, Sofie A. Harrison

Theses: Doctorates and Masters

Nutrient inputs from productive marine environments have been shown to directly and indirectly subsidise primary producers and consumers in terrestrial ecosystems (e.g. Polis and Hurd 1995; 1996; Anderson and Polis 1998; 1999). But does this theory hold true on islands surrounded by oligotrophic waters, which account for a significant proportion of the marine environment? The aim of the present study was to examine the applicability of the spatial subsidisation hypotheses proposed by Polis and his co-authors to an oligotrophic system in south-western region of Western Australia. These aims were achieved by comparing soil and plant nutrients, and the nitrogen stable …

The Role Of Farm Dams As Refugia For Aquatic Invertebrates In A Salinised Landscape, South Western Australia, Jean-Michel Benier

Theses: Doctorates and Masters

In a salinised landscape farm dams may represent the last truly freshwater surface resource, and therefore provide refuge habitats for the biota of wetlands affected by increasing salinity. One wetland threatened by increased salinity in south-west Western Australia is Lake Toolibin. It is listed as a Wetland of International Importance under the Ramsar Convention in recognition of its high conservation value, and remediation actions to halt (and possibly reverse) further increases in salinity are being undertaken at this wetland. Farm dams act as aquatic refugia if they convey resistance and/or resilience to the biotic communities of a disturbed habitat. This …

In Vitro Propagation Of Some Western Australian Seagrasses, Julia Wilson

Theses: Doctorates and Masters

The development of a successful protocol for micropropagating seagrass provides a valuable tool for seagrass-restoration programs and a facility to study their biology (especially their physiology). This work reports on some of the culture requirements of some seagrasses that are commonly found in Western Australia: Posidonia coriacea, P. sinuosa, P. australis and Halophila ovalis. The protocol developed for H. ovalis allows very rapid multiplication and sustainable growth of cultures while the protocol developed for Posidonia requires further development. The culture of Posidonia cariacea proved to be problematic however experimental media that provided insights into its culture conditions. The carbohydrate source …

Aspects Of The Taxonomy And Ecology Of The Ground Beetle (Coleoptera: Carabidae) Assemblage Of The Swan Coastal Plain : (With Particular Reference To Habitat Fragmentation And The Quindalup Dune System), Nadine A. Guthrie

Theses: Doctorates and Masters

Long term studies encompassing seasonal variation in abundance and species present, forming base-line phenological data, arc required to understand the responses of the carabid (Ground Beetle) fauna to major habitat changes. In addition, few habitats unaffected by human disturbance remain in Australia, and evaluation of these fauna in these areas is required before further habitat loss occurs. Generally an unknown group of terrestrial predatory invertebrates in Australia, carabids have been the subjects of few ecological studies in this country. This restricts the utility of the Carabidae in environmental or conservation assessment programs in Australia. A study was initiated to assess …

Origin And Fate Of Organic Matter In South-West Australian Wetlands, Darren Stuart Ryder

Theses: Doctorates and Masters

The development and local distribution of organic soils in Australia have been poorly documented. Within Western Australia, conditions conducive to the accumulation of organic matter are geographically restricted and generally occur in coastal and/or forested landscapes. An extensive system of wetlands with peal soils occurs in the Muir-Unicup region in the far south west of Western Australia. Bokarup Swamp, Kodjinup Swamp and Noobijup Lake are representative of the wetlands occurring in this region. They arc shallow (

Changes To The Distribution Of Posidonia Seagrass Communities Of James Point, In Response To The Development Of Cockburn Sound, Western Australia, Anthony Muscara

Theses: Doctorates and Masters

Australia’s oceans provide many economic and environmental benefits both nationally and regionally, and are of particular social, recreational and cultural importance. Western Australia's most intensively used marine embayment is Cockburn Sound, is Cockburn Sound, it supports one of the most extensive Posidoni seagrass communities in Western Australia. The protected coastal waters off the southern metropolitan coastline of Perth arc utilised intensively for industrial, commercial and recreational purposes. Over the past 50 years, wastes have been routinely discharged into Cockburn Sound causing extensive phytoplankton and epiphyte blooms, particularly during the 1960's and 1970's. The development of industrial and naval facilities and …

The Role Of Benthic Macroalgae In Sediment-Water Nutrient Cycling In The Swan-Canning Estuarine System, Western Australia, Helen Lee Astill

Theses: Doctorates and Masters

This study documented the macroalgal assemblages of the Swan-Canning Estuarine System (SCES) over a two year period, and the influences of several environmental parameters on the assemblages. In addition, the Impacts of unattached macroalgal accumulations on benthic nutrient fluxes and microbial communities were investigated. Benthic macroalgal assemblages and physico-chemical regimes were monitored in the SCES, to determine temporal and spatial changes in macroalgal communities and the influence of environmental factors in these changes. Physico-chemical regimes demonstrated strong seasonal changes, which revolved around the onset and cessation of freshwater flows in winter (May to September). In the months after freshwater flows, …