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The Effects Of Light Reduction Treatments On Mobile Epifaunain An Amphibolis Griffithii (Black) Den Hartog Seagrass Ecosystem, Helen Barwick Jan 2006

The Effects Of Light Reduction Treatments On Mobile Epifaunain An Amphibolis Griffithii (Black) Den Hartog Seagrass Ecosystem, Helen Barwick

Theses : Honours

One of the main anthropogenic disturbances to seagrass meadows in Australia is reduction in light availability, through nutrient enrichment or suspended sediments. Dredging can create suspended sediment plumes from the expulsion of particulates into the water column and in tum reduces light penetration to seagrass ecosystems. Preliminary investigations have demonstrated that light reduction for different intensities and durations results in reduced seagrass and epiphytic algae biomass. The main aim of this study was to determine the effects of different intensities and durations of light reduction on epifaunal assemblages in Amphibolis griffithii seagrass meadows in Jurien Bay, Western Australia. This was ...


Water Stress Vulnerability Of Four Banksia Species In Contrasting Ecohydrological Habitats On The Gnangara Mound, Western Australia., Caroline Canham Jan 2006

Water Stress Vulnerability Of Four Banksia Species In Contrasting Ecohydrological Habitats On The Gnangara Mound, Western Australia., Caroline Canham

Theses : Honours

The distribution of obligate and facultative phreatophytic vegetation reflects the gradient of ecohydrological habitats in a landscape. Preliminary investigations of Banksia vulnerability to xylem embolism have reported that obligate phreatophytes are more susceptible to water stress than facultative phreatophytes (Froend & Drake 2006). A quantitative measure of plant susceptibility to water stress is vital when establishing environmental water requirements. This study investigated interspecific differences in vulnerability to water stress for two facultative phreatophytes (B. attenuata and B. menziesii) and two obligate pln·eatophytes (B. ilicifolia and B. littoralis) at the same position along an ecohydrological gradient on the Gnangara Groundwater Mound ...


Pollen Characteristics Of Grevillea Species Determined By In Vitro Germination, Rebecca Parsons Jan 2006

Pollen Characteristics Of Grevillea Species Determined By In Vitro Germination, Rebecca Parsons

Theses : Honours

Germination of pollen in vitro is a common technique used to assess the ability of pollen to germinate under a variety of conditions. The ability to determine the viability of a pollen grain, and optimal conditions for maximum germination and storage are important for hybridisation. A means of storing pollen, while maintaining viability, enables inter-species hybridisation between species that are spatially and temporally (flowering time) separated. The ultimate aim of hybridisation is seed set and in order to increase this in a genus renowned for a very low fruit to flower ratio, maximum pollen germination must be obtained. Therefore, by ...


Genetic Diversity And Gene Flow In Fragmented Populations Of The Rare Shrub, Calothamnus Sp. Whicher, Sean Stankowski Jan 2006

Genetic Diversity And Gene Flow In Fragmented Populations Of The Rare Shrub, Calothamnus Sp. Whicher, Sean Stankowski

Theses : Honours

Ca/othamnus sp. Whicher (Myrtaceae) is a narrow range endemic shrub restricted to ironstone soils near the town of Busselton in south-western Australia. Due to extensive land clearing for agriculture and mineral exploration, the species is fragmented over the majority of its range. In the present study, microsatellite markers were used to characterise levels of genetic diversity and describe levels of differentiation and gene flow among seven small, isolated road verge populations. Allelic diversity within the taxon over the six microsatellites was high (A = 17.6 ± 1.6). Diversity within populations was considerably lower (A = 5.19 ± 1.27), and ...