Dissertationen zum Thema „Plant introduction South Australia“
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1
Kloot, P. M. „Studies in the alien flora of the cereal rotation areas of South Australia /“. Title page, contents and summary only, 1985. http://web4.library.adelaide.edu.au/theses/09PH/09phk655.pdf.
2
Venn, Susanna Elizabeth, und Susanna Venn@nt gov au. „Plant recruitment across alpine summits in south-eastern Australia“. La Trobe University. School of Life Sciences, 2007. http://www.lib.latrobe.edu.au./thesis/public/adt-LTU20080526.160815.
Annotation:
This thesis investigated aspects of plant recruitment across an altitudinal gradient of mountain tops in the Victorian Alps, Australia, and provides a baseline for the patterns and processes of alpine plant recruitment in the absence of large-scale disturbance.
The patterns in alpine vegetation across the study sites were described in relation to abiotic environmental factors. Temperatures were lower and precipitation was higher at the high altitude sites. The vegetation did not differ significantly between the sites, although sites at low altitudes were shrubbier than those at high altitudes. Analysis of the soil seed bank revealed high mean densities of germinable seed (80 to 1400 seeds m-2) across the gradient of sites. The similarity between the seed bank samples and the standing vegetation was low (qualitative similarity: 0.08 to 0.2; quantitative similarity: 0.03 to 0.19).
In laboratory germination experiments, I found rapid and substantial germination. Final percent germination was above 90% for most species. One species, Aciphylla glacialis, showed evidence of dormancy mechanisms. In subsequent experiments, I found that innate primary seed dormancy in this species could be broken with cold-wet stratification.
There were no significant patterns in natural seedling recruitment across the altitudinal gradient. Similarities between the seedling flora and the standing vegetation
were low (qualitative similarity: 0.18 to 0.45: quantitative similarity 0.04 to 0.09). Mean seedling density was best predicted by a combination of soil wilting point, altitude and plant litter. In some cases, seedling density was greater than 80 seedlings m-2.
The relative importance of either negative (competitive) or positive (facilitative) interactions between seedlings with adjacent vegetation were investigated in relation to seed germination, seedling growth and seedling survival. Facilitative interactions were common at the higher altitude sites. At lower altitudes, facilitative and competitive interactions were common. Without close neighbours at high altitudes, seedlings were unlikely to survive into their second year.
An understanding of plant recruitment can provide a useful basis for predicting species responses to large-scale disturbance and climate change.
3
Venn, Susanna Elizabeth. „Plant recruitment across alpine summits in south-eastern Australia /“. Access full text, 2007. http://www.lib.latrobe.edu.au/thesis/public/adt-LTU20080526.160815/index.html.
Annotation:
Thesis (Ph.D.) -- La Trobe University, 2007.Research. "A thesis submitted in total fulfillment of the requirements for the degree of Doctor of Philosophy, Department of Botany, School of Life Sciences, Faculty of Science, Technology and Engineering, La Trobe University, Bundoora". Includes bibliographical references (leaves 173-187). Also available via the World Wide Web.
4
Heshmatti, Gholam Ali. „Plant and soil indicators for detecting zones around water points in arid perennial chenopod shrublands of South Australia /“. Title page, contents and summary only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phh584.pdf.
Annotation:
Thesis (Ph. D.)--University of Adelaide, Dept. of Botany, 1997.Errata page is behind title page (p. i). Copies of author's previously published articles inserted. Includes bibliographical references (leaves 121-156).
5
Sparrow, Ashley. „A geobotanical study of the remnant natural vegetation of temperate South Australia“. Title page, contents and summary only, 1991. http://web4.library.adelaide.edu.au/theses/09PH/09phs7368.pdf.
6
Pritchard, Deborah Leeanne. „Phosphorus bioavailability from land-applied biosolids in south-western Australia“. Thesis, Curtin University, 2005. http://hdl.handle.net/20.500.11937/2380.
Annotation:
The annual production of biosolids in the Perth region during the period of this study was approximately 13,800 t dry solids (DS), being supplied by three major wastewater treatment plants. Of this, 70% was typically used as a low-grade fertiliser in agriculture, representing an annual land use area of around 1,600 ha when spread between 5 and 7 t DS/ha. Loading rates of biosolids are typically based on the nitrogen (N) requirements of the crop to be grown, referred to as the N Limiting Biosolids Application Rate (NLBAR). A consequence of using the NLBAR to calculate loading rates is that phosphorus (P) is typically in excess of plant requirement. The resultant high loading rates of P are considered in the guidelines developed for the agricultural use of biosolids in Western Australia, but lack research data specific to local conditions and soil types. Regulatory changes throughout Australia and globally to protect the environment from wastewater pollution have created a need for more accountable and balanced nutrient data. Experiments presented in this thesis were undertaken to ascertain: the percentage relative effectiveness (RE) of biosolids as a source of plant available P compared with inorganic P fertiliser; loading rates to best supply P for optimum crop growth; P loading rates of risk to the environment; and the forms of P in local biosolids. Therefore, both the agronomic and environmental viewpoints were considered. Anaerobically digested and dewatered biosolids produced from Beenyup Wastewater Treatment Plant, Perth with a mean total P content of 2.97% dry weight basis (db) were used in a series of glasshouse, field and laboratory experiments. The biosolids were sequentially fractionated to identify the forms of P present and likewise in soil samples after applying biosolids or monocalcium phosphate (MCP).The biosolid P was predominantly inorganic (92%), and hence the organic fraction (8%) available for mineralisation at all times would be extremely low. The most common forms of biosolid P were water-soluble P and exchangeable inorganic P (66%), followed by bicarbonate extractable P (19%) and the remaining P as inorganic forms associated with Fe, Al and Ca (14%). Following the application of biosolids to a lateritic soil, the Fe and Al soil fractions sorbed large amounts of P, not unlike the distribution of P following the addition of MCP. Further investigation would be required to trace the cycling of biosolid P in the various soil pools. The growth response of wheat (Triticum aestivum L.) to increasing rates of biosolids and comparable rates of inorganic P as MCP, to a maximum of 150 mg P/kg soil was examined in the glasshouse. The percentage relative effectiveness (RE) of biosolids was calculated using fitted curve coefficients from the Mitscherlich equation: y = a (1-b exp–cx) for dry matter (DM) production and P uptake. The initial effectiveness of biosolid P was comparable to that of MCP with the percentage RE of biosolids averaging 106% for DM production of wheat shoots and 118% for shoot P uptake at 33 days after sowing (DAS) over three consecutive crops. The percentage residual value (RV) declined at similar rates for DM production in MCP and biosolids, decreasing to about 33% relative to freshly applied MCP in the second crop and to approximately 16% in the third crop. The effectiveness of biosolid P was reduced significantly compared with inorganic P when applied to a field site 80 km east of Perth (520 mm annual rainfall). An infertile lateritic podsolic soil, consistent with the glasshouse experiment and representative of a soil type typically used for the agricultural application of biosolids in Western Australia was used.Increasing rates of biosolids and comparable rates of triple superphosphate (TSP), to a maximum of 145 kg P/ha were applied to determine a P response curve. The percentage RE was calculated for seasonal DM production, final grain yield and P uptake in wheat followed by lupin (Lupinus angustifolius L.) rotation for the 2001 and 2002 growing seasons, respectively. In the first year of wheat, the RE for P uptake in biosolids compared with top-dressed TSP ranged from 33% to 55% over the season and by grain harvest was 67%. In the second year, and following incorporation with the disc plough at seeding, the RE for P uptake by lupins in biosolids averaged 79% over the growing season compared with top-dressed TSP, and by grain harvest the RE was 60%. The residual value (RV) of lupins at harvest in biosolids compared with freshly applied TSP was 47%. The non-uniform placement of biosolids (i.e. spatial heterogeneity) was primarily responsible for the decreased ability of plant roots to absorb P. The P was more effective where biosolids were finely dispersed throughout the soil, less so when roughly cultivated and least effective when placed on the soil surface without incorporation. The RE for grain harvest of wheat in the field decreased from 67% to 39% where biosolids were not incorporated (i.e. surface-applied). The RE could also be modified by factors such as soil moisture and N availability in the field, although it was possible to keep these variables constant in the glasshouse. Consequently, absolute values determined for the RE need to be treated judiciously. Calculations showed that typical loading rates of biosolids required to satisfy agronomic P requirements of wheat in Western Australia in the first season could vary from 0 to 8.1 t DS/ha, depending on soil factors such as the P Retention Index (PRI) and bicarbonate available P value.Loading rates of biosolids were inadequate for optimum P uptake by wheat at 5 t DS/ha (i.e. 145 kg P/ha) based on the NLBAR on high P sorbing soils with a low fertiliser history (i.e. PRI >15, Colwell bicarbonate extractable P <15 mg P/kg). On soils of PRI <2 mL/g however, biosolids applied at identical loading rates would result in high concentrations of available P. Further work on sites not P deficient would be necessary to validate these findings on farmed soils with a regular history of P fertiliser. The sieving of soil samples used in the field experiment to remove stones and coarse organic matter prior to chemical analysis inadvertently discarded biosolids particles >2 mm, and thus their was little relationship between soil bicarbonate extractable P and P uptake by plants in the field. The risk of P leaching in biosolids-amended soil was examined over a number of different soil types at comparable rates of P at 140 mg P/kg (as either biosolids or MCP) in a laboratory experiment. Given that biosolids are restricted on sites prone to water erosion, the study focussed on the movement of water-soluble P by leaching rather than by runoff of water-soluble P and particulate P. In general the percentage soluble reactive P recovered was lower in soils treated with biosolids than with MCP, as measured in leachate collected using a reverse soil leachate unit. This was particularly evident in acid washed sand with SRP measuring 14% for biosolids and 71% for MCP, respectively, although the differences were not as large in typical agricultural soils. Specific soil properties, such as the PRI, pH, organic carbon and reactive Fe content were negatively correlated to soluble reactive P in leachate and thus reduced the risk of P leaching in biosolids-amended soil.Conversely, the total P and bicarbonate extractable P status of the soils investigated were unreliable indicators as to the amount of P leached. On the basis of the experiments conducted, soils in Western Australia were categorised according to their ability to minimise P enrichment and provide P necessary for crop growth at loading rates determined by the NLBAR. Biosolids applied at the NLBAR to soils of PRI >2mL/g with reactive Fe >200 mg/kg were unlikely to necessitate P loading restrictions. Although specific to anaerobically digested biosolids cake applied to Western Australian soils, the results will be of relevance to any industry involved in the land application of biosolids, to prevent P contamination in water bodies and to make better use of P in crop production.
7
Pritchard, Deborah Leeanne. „Phosphorus bioavailability from land-applied biosolids in south-western Australia“. Curtin University of Technology, Muresk Institute, 2005. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=16492.
Annotation:
The annual production of biosolids in the Perth region during the period of this study was approximately 13,800 t dry solids (DS), being supplied by three major wastewater treatment plants. Of this, 70% was typically used as a low-grade fertiliser in agriculture, representing an annual land use area of around 1,600 ha when spread between 5 and 7 t DS/ha. Loading rates of biosolids are typically based on the nitrogen (N) requirements of the crop to be grown, referred to as the N Limiting Biosolids Application Rate (NLBAR). A consequence of using the NLBAR to calculate loading rates is that phosphorus (P) is typically in excess of plant requirement. The resultant high loading rates of P are considered in the guidelines developed for the agricultural use of biosolids in Western Australia, but lack research data specific to local conditions and soil types. Regulatory changes throughout Australia and globally to protect the environment from wastewater pollution have created a need for more accountable and balanced nutrient data. Experiments presented in this thesis were undertaken to ascertain: the percentage relative effectiveness (RE) of biosolids as a source of plant available P compared with inorganic P fertiliser; loading rates to best supply P for optimum crop growth; P loading rates of risk to the environment; and the forms of P in local biosolids. Therefore, both the agronomic and environmental viewpoints were considered. Anaerobically digested and dewatered biosolids produced from Beenyup Wastewater Treatment Plant, Perth with a mean total P content of 2.97% dry weight basis (db) were used in a series of glasshouse, field and laboratory experiments. The biosolids were sequentially fractionated to identify the forms of P present and likewise in soil samples after applying biosolids or monocalcium phosphate (MCP).The biosolid P was predominantly inorganic (92%), and hence the organic fraction (8%) available for mineralisation at all times would be extremely low. The most common forms of biosolid P were water-soluble P and exchangeable inorganic P (66%), followed by bicarbonate extractable P (19%) and the remaining P as inorganic forms associated with Fe, Al and Ca (14%). Following the application of biosolids to a lateritic soil, the Fe and Al soil fractions sorbed large amounts of P, not unlike the distribution of P following the addition of MCP. Further investigation would be required to trace the cycling of biosolid P in the various soil pools. The growth response of wheat (Triticum aestivum L.) to increasing rates of biosolids and comparable rates of inorganic P as MCP, to a maximum of 150 mg P/kg soil was examined in the glasshouse. The percentage relative effectiveness (RE) of biosolids was calculated using fitted curve coefficients from the Mitscherlich equation: y = a (1-b exp–cx) for dry matter (DM) production and P uptake. The initial effectiveness of biosolid P was comparable to that of MCP with the percentage RE of biosolids averaging 106% for DM production of wheat shoots and 118% for shoot P uptake at 33 days after sowing (DAS) over three consecutive crops. The percentage residual value (RV) declined at similar rates for DM production in MCP and biosolids, decreasing to about 33% relative to freshly applied MCP in the second crop and to approximately 16% in the third crop. The effectiveness of biosolid P was reduced significantly compared with inorganic P when applied to a field site 80 km east of Perth (520 mm annual rainfall). An infertile lateritic podsolic soil, consistent with the glasshouse experiment and representative of a soil type typically used for the agricultural application of biosolids in Western Australia was used.
Increasing rates of biosolids and comparable rates of triple superphosphate (TSP), to a maximum of 145 kg P/ha were applied to determine a P response curve. The percentage RE was calculated for seasonal DM production, final grain yield and P uptake in wheat followed by lupin (Lupinus angustifolius L.) rotation for the 2001 and 2002 growing seasons, respectively. In the first year of wheat, the RE for P uptake in biosolids compared with top-dressed TSP ranged from 33% to 55% over the season and by grain harvest was 67%. In the second year, and following incorporation with the disc plough at seeding, the RE for P uptake by lupins in biosolids averaged 79% over the growing season compared with top-dressed TSP, and by grain harvest the RE was 60%. The residual value (RV) of lupins at harvest in biosolids compared with freshly applied TSP was 47%. The non-uniform placement of biosolids (i.e. spatial heterogeneity) was primarily responsible for the decreased ability of plant roots to absorb P. The P was more effective where biosolids were finely dispersed throughout the soil, less so when roughly cultivated and least effective when placed on the soil surface without incorporation. The RE for grain harvest of wheat in the field decreased from 67% to 39% where biosolids were not incorporated (i.e. surface-applied). The RE could also be modified by factors such as soil moisture and N availability in the field, although it was possible to keep these variables constant in the glasshouse. Consequently, absolute values determined for the RE need to be treated judiciously. Calculations showed that typical loading rates of biosolids required to satisfy agronomic P requirements of wheat in Western Australia in the first season could vary from 0 to 8.1 t DS/ha, depending on soil factors such as the P Retention Index (PRI) and bicarbonate available P value.
Loading rates of biosolids were inadequate for optimum P uptake by wheat at 5 t DS/ha (i.e. 145 kg P/ha) based on the NLBAR on high P sorbing soils with a low fertiliser history (i.e. PRI >15, Colwell bicarbonate extractable P <15 mg P/kg). On soils of PRI <2 mL/g however, biosolids applied at identical loading rates would result in high concentrations of available P. Further work on sites not P deficient would be necessary to validate these findings on farmed soils with a regular history of P fertiliser. The sieving of soil samples used in the field experiment to remove stones and coarse organic matter prior to chemical analysis inadvertently discarded biosolids particles >2 mm, and thus their was little relationship between soil bicarbonate extractable P and P uptake by plants in the field. The risk of P leaching in biosolids-amended soil was examined over a number of different soil types at comparable rates of P at 140 mg P/kg (as either biosolids or MCP) in a laboratory experiment. Given that biosolids are restricted on sites prone to water erosion, the study focussed on the movement of water-soluble P by leaching rather than by runoff of water-soluble P and particulate P. In general the percentage soluble reactive P recovered was lower in soils treated with biosolids than with MCP, as measured in leachate collected using a reverse soil leachate unit. This was particularly evident in acid washed sand with SRP measuring 14% for biosolids and 71% for MCP, respectively, although the differences were not as large in typical agricultural soils. Specific soil properties, such as the PRI, pH, organic carbon and reactive Fe content were negatively correlated to soluble reactive P in leachate and thus reduced the risk of P leaching in biosolids-amended soil.
Conversely, the total P and bicarbonate extractable P status of the soils investigated were unreliable indicators as to the amount of P leached. On the basis of the experiments conducted, soils in Western Australia were categorised according to their ability to minimise P enrichment and provide P necessary for crop growth at loading rates determined by the NLBAR. Biosolids applied at the NLBAR to soils of PRI >2mL/g with reactive Fe >200 mg/kg were unlikely to necessitate P loading restrictions. Although specific to anaerobically digested biosolids cake applied to Western Australian soils, the results will be of relevance to any industry involved in the land application of biosolids, to prevent P contamination in water bodies and to make better use of P in crop production.
8
Frost, William E. „The ecology of cereal rust mite Abacarus hystrix (Nalepa) in irrigated perennial dairy pastures in South Australia /“. Title page, contents and summary only, 1995. http://web4.library.adelaide.edu.au/theses/09PH/09phf9398.pdf.
9
Bhatti, Muhammad Ali. „Genetic variation in naturalized wild radish (Raphanus raphanistrum L.) populations in the mediterranean climate of south-western Australia“. University of Western Australia. School of Plant Biology, 2004. http://theses.library.uwa.edu.au/adt-WU2005.0012.
Annotation:
[Truncated abstract] Wild radish (Raphanus raphanistrum L.), an outcrossing annual plant, is one of the most widespread and successful colonising weeds in the Australian wheat belt. It was introduced accidentally during the latter part of the 19th century, apparently independently through the major ports of southern Australia. The widespread success of wild radish, and therefore the likelihood of distinct populations, gives us the opportunity to study the colonizing process with adaptation in annual outbreeding species, and to explore their genetic diversity. The aims of this thesis were to study the genetic diversity of wild radish and to investigate which factors are important in its success. After an initial review of the literature (chapter 2), the thesis describes experiments where genetic variation between and within populations was compared at 55 sites in transects across the wheat belt and high rainfall zones of temperate Western Australia (chapter 3). In chapter 4, variation in life history traits was compared with variation in AFLP molecular markers. The role of seed dormancy in the survival of the species was examined in chapter 5, and variation in the oil content of seeds and their fatty acid composition was examined in chapter 6. Finally, the results were discussed in chapter 7 with special reference to the adaptive value of outcrossing in annual weeds. The results suggest that wild radish has evolved to fit the Australian environment. However, measurement of 14 morphological and phenological characters showed that in most cases within site variation was much greater than that between sites. Most of the variation between sites was associated with geoclusters, a name given to zones of similar environmental conditions in regard to rainfall and temperature. Thus plants from areas with high rainfall and low temperature produced longer, wider pods with more segments, heavier seeds and flowered later than plants from more arid areas.
10
Barrett, Sarah. „Phytotoxic effects of phosphite in native plant communities on the south coast of Western Australia“. Thesis, Barrett, Sarah (2001) Phytotoxic effects of phosphite in native plant communities on the south coast of Western Australia. PhD thesis, Murdoch University, 2001. https://researchrepository.murdoch.edu.au/id/eprint/32427/.
11
Ross, Karen School of Biological Earth & Environmental Sciences UNSW. „Effects of fragmentation and disturbance on a eucalypt open-forest plant community in south-eastern Australia“. Awarded by:University of New South Wales. School of Biological, Earth and Environmental Sciences, 2005. http://handle.unsw.edu.au/1959.4/22454.
Annotation:
This study documented effects of fragmentation and disturbance on a coastal eucalypt dry open-forest plant community at Port Stephens-Myall Lakes, south-eastern Australia. The study evaluated the relative influence of fragment size (range <1-75ha), fragment or edge age (< 1-25y), time since fire (5-25y) and anthropogenic disturbance (minor, major) on microclimate, native plant species richness and weed invasion. Plots were sampled for native and exotic species richness per 25 m2 and edge transects for light, soil moisture, soil temperature, vegetation structure, native species richness and exotic species richness and cover. Depths of edge influence (DEI) were all < 20m inside the forest edge. Younger edge zones were lighter, had hotter and drier soils and more native species than forest interiors. Older edge zones were shadier, had warmer and moister soils and fewer native species than forest interiors, due to vegetation thickening in the edge zone. Light and soil moisture followed linear or monotonic edge-to-interior gradients in younger edges, but more complex patterns in older edges. Soil-temperature DEI decreased with increasing edge age. Fragment size had little influence on edge effects, but those for light developed more rapidly in smaller fragments, and recent fire was associated with reduced richness in edge zones of smaller fragments. Both anthropogenic disturbance and fire enlarged DEI for native species richness. Major anthropogenic disturbance coupled with fragmentation produced a stronger and more immediate loss of native species than fragmentation alone. Small fragments with minor disturbance had fewer native species per 25 m2 than larger fragments, but only after >10y since fragmentation. Analysis of forest interior portions of transects revealed that edge effects, and possibly disturbance, were largely responsible for this loss of native species with time, rather than effects of area. Despite a viable soil seed bank in fragments and the surrounding matrix, weed invasion in fragments was minimal. Exotic species were concentrated in edge zones, and were promoted by major anthropogenic disturbance within fragments. Results were highly dependent on fragment or edge age, and external influences of fragmentation (edge effects and disturbance), were more important than biogeographic (area-driven) factors. Impacts of fragmentation were compounded when combined with disturbance.
12
Noack, Denise Helen. „The contribution of heritage agreements to conservation in the Murray Mallee of South Australia /“. Title page, contents and abstract only, 1991. http://web4.library.adelaide.edu.au/theses/09ENV/09envn739.pdf.
13
Mensforth, Lisa. „Water use strategy of Melaleuca halmaturorum in a saline swamp /“. Title page, contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phm548.pdf.
14
Mitchell, Patrick John. „From conduits to communities : plant water use strategies and evapotranspiration in a semi-arid ecosystem in south-western Australia“. University of Western Australia. School of Plant Biology, 2009. http://theses.library.uwa.edu.au/adt-WU2010.0034.
Annotation:
[Truncated abstract] Understanding the ecohydrological dynamics of native vegetation can provide a benchmark for future efforts to restore landscape hydrology and allow predictions of potential landscape responses to climate uncertainty and associated changes in vegetation cover. The key drivers of evapotranspiration (Et) involved in maintaining a hydrological balance that minimises deep drainage in semi-arid ecosystems operate at a range of scales, and in this thesis I assessed the water relations of functionally and taxonomically diverse plant communities in south-western Australia from the leaf-level to ecosystem scale. For three key communities; heath shrubland, mallee (small multistemmed eucalypt) -heath, and open eucalypt woodland, populating a typical catenary sequence of soil types along a slope, I addressed the following questions: 1) What are the predominant water use strategies of wheatbelt native plant communities and what underlying trade-offs determine the distribution of plant water use strategies along the topographical gradient? 2) What are the roles of soil water and hydraulic limitation in controlling the spatial and temporal dynamics of transpiration in different functional types? 3) What is the magnitude and partitioning of total Et in the woodland community and what processes determine Et fluxes on a seasonal and annual basis? 4) What are the seasonal differences in Et among contrasting community-types and how do these patterns relate to canopy attributes and transpiration capacity along the topographical gradient? A key philosophical step in working with species-rich communities was to develop the concept of 'hydraulic functional types' (HFTs) to identify groupings of species using associations of physiological and morphological traits that define their hydrological functioning. .... However, as shallow soils dried during spring and summer, Et fluxes were significantly lower at the heath site (0.35 versus 0.66 mm day-1 for the woodland in February), demonstrating that the seasonality of Et fluxes differentiates communityscale contributions to regional water balance. Land-surface exchange of water over native vegetation is by no means uniform, but varies according to the spatial and temporal availability of water along topographical gradients. In general, shallow soils present fewer opportunities for water use partitioning and favour drought hardiness and a transpiration response that tracks recent rainfall patterns, whereas deeper soils promote greater differentiation in water use strategy and support canopies responsive to atmospheric demand. This thesis provides a unique description of ecosystem water balance in a global biodiversity hotspot by viewing complex vegetation mosaics in terms of their relevant hydrological units. This information is fundamental to sustainable agroforestry and revegetation efforts and our ability to gauge possible changes in vegetation structure and function under a changing climate.
15
Rutten, Karin. „Studies on the biomass, diversity and nutrient relationships of macroalgae and seagrasses in Lake Illawarra, New South Wales, Australia“. School of Earth and Environmental Sciences - Faculty of Science, 2007. http://ro.uow.edu.au/theses/22.
Annotation:
Lake Illawarra is a shallow barrier lagoon, located on the south-eastern coast of Australia. Eutrophication, referring to the enrichment of water by inorganic plant nutrients (primarily nitrogen and phosphorus), is one of the key environmental problems in Lake Illawarra. Management of macroalgae in Lake Illawarra is a major issue; excessive blooms of macroalgae, resulting in odours, access problems and community concern over Lake health, have led to many management strategies, including direct harvesting of algal biomass. Little information is available on the factors responsible for excessive growth of macroalgae in Lake Illawarra, although over supply of nutrients has often been cited as the primary cause. The aim of this study was to investigate the distribution, diversity, biomass and nutrient relationships of seagrasses and macroalgae in Lake Illawarra, and to determine what contribution, if any, macrophytes make to the Lake’s nutrient budget. Firstly, detailed species lists and taxonomic descriptions were prepared for macrophytes occurring in Lake Illawarra, between June 2000 and July 2003. This study focused primarily on shallow (< 1 m depth), inshore areas of Lake Illawarra, where problematic macroalgal blooms frequently occur. Seagrasses found in Lake Illawarra are Zostera capricorni, Ruppia megacarpa, Halophila ovalis and Halophila decipiens. In addition, 35 species of macroalgae were recorded and described; these included: 14 species from 7 genera of green macroalgae; 9 species from 9 different genera of brown macroalgae; and, 8 species from 8 genera of red macroalgae. The biomass of seagrasses and macroalgae in Lake Illawarra were documented seasonally (winter and summer) at four key Lake Illawarra sites; these included two R. megacarpa sites and two Z. capricorni sites. Average R. megacarpa and Z. capricorni dry weight (DW) biomasses (above and below-ground material) ranged from 54.8 - 440 g DW m 2 and 58.1 - 230 g DW m 2, respectively. Significant die-back, particularly of Z. capricorni, occurred in winter; summer biomasses were up to 1.5 - 3.9 times higher than winter biomasses. Below-ground material (roots and rhizomes) comprised 20 - 45 % and 40 - 67 % of total plant biomass for R. megacarpa and Z. capricorni, respectively. Macroalgal biomass in 2000-03 was notably lower than in previous decades; this may be due to drought, as well as improvements in water quality. Maximum biomasses of macroalgae recorded in the present study were 150 - 370 g DW m 2. Algal blooms were composed primarily of the filamentous chlorophytes, Chaetomorpha linum and Chaetomorpha billardierii. The highest seagrass (R. megacarpa) and macroalgal biomasses usually occurred at the Oasis Caravan Park site, located along the eastern Lake Illawarra peninsula. Tissue nutrient analyses were conducted on the most abundant seagrasses (Z. capricorni and R. megacarpa) and macroalgae occurring at four sites in Lake Illawarra, between spring 2000 and winter 2002. Total C contents of macrophytes varied from 23.3 - 42.0 % C for seagrasses, and 28.0 - 39.7 % C for macroalgae. The δ13C and δ15N contents of seagrasses ranged from -7.7 to 15.9 ‰ and 0.7 - 9.0 ‰, respectively. The most significant seasonal variations in seagrass δ13C contents and, to a lesser extentδ15N contents, occurred in Z. capricorni located at the source of fresh water input, Mullet Creek. Macroalgae showed a greater variation in isotopic signatures than the seagrasses, ranging from 4.9 to 19.8 ‰ (δ13C) and 1.8 - 14.6 ‰ (δ15N). Differences between species at the same site were often more significant than differences between the same species at different sites. Seagrass leaf N and P contents ranged from 1.74 - 4.13 % (mean ± s.e.: 2.62 ± 0.05 % N) and 0.12 - 0.59 % P (mean ± s.e.: 0.31 ± 0.01 % P); leaf N and P contents were typically double those of roots/rhizomes. N contents varied between species and sites, but P contents of Z. capricorni were usually significantly higher than R. megacarpa. Z. capricorni C and N contents increased in winter, corresponding to lower winter biomasses. Seagrass leaf biomass and tissue P contents peaked in summer 2002, which may be related to higher water column P concentrations in summer. Tissue N and P contents of macroalgae were more variable than those of the seagrasses, and ranged from 0.85 - 3.95 % N and 0.03 - 0.58 % P. The average C/P (808 ± 65) and N/P (47.9 ± 3.47) molar ratios of macroalgae were typically double those of the seagrasses. Low concentrations of tissue P, with respect to N, in R. megacarpa and macroalgae implied P limitation on several occasions, particularly when macrophyte biomasses were low. High tissue N contents in Lake Illawarra macrophytes suggested N limitation of biomass formation rarely occurred. Evidence of P, rather than N, limitation in macrophytes is surprising considering most data suggests N limitation of phytoplankton production in Lake Illawarra. The estimated pools of N and P contained in Lake Illawarra macrophyte biomass were similar to those present in the water column, but appeared minute when compared to the N and P stored within Lake Illawarra sediment. Laboratory culture experiments were conducted to evaluate the response of the most problematic alga, Chaetomorpha linum, to nutrient enrichment. Water temperatures of 20 - 25°C were found to promote the highest growth rates (up to 27 % WW d 1) of C. linum, but high growth rates (13 % WW d 1) were also recorded at 10°C, the lowest winter water temperature recorded in Lake Illawarra. Enrichment with N, rather than P, had the greatest effect on C. linum; growth rates were significantly reduced in treatments without added N, but treatments with N-alone were statistically similar to N+P treatments. It was concluded that in Lake Illawarra, C. linum was strongly nitrogen limited. The ability of C. linum to grow successfully in culture, under a range of nutrient treatments, and without added phosphorus, in particular, correlates with the excessive growth of this alga in Lake Illawarra. This study has made a significant contribution to the understanding of seagrass and macroalgal growth, biomass and distribution in Lake Illawarra. This information will assist with the long-term management of macroalgal problems in Lake Illawarra.
16
George, Amy Kathryn. „Eucalypt regeneration on the Lower Murray floodplain, South Australia“. Connect to this title online, 2004. http://hdl.handle.net/2440/37706.
Annotation:
Vegetation along the River Murray floodplains has been shown to be in a severe state of decline. This decline is amplified by the impositions of river regulation. In South Australia, where vegetation losses have been great, regeneration is limited and may result in not only individual tree losses but also widespread population decline. This study aimed to examine the relationship between river flows and the regeneration process in populations of Eucalyptus camaldulensis and Eucalyptus largiflorens. The current structure of the populations was examined to determine if a viable number of varying age-classed trees were present. Tree surveys conducted at Banrock Station determined that while densities were low for both species, E. camaldulensis had a more sustainable population structure than E. largiflorens. Growth stages for both species illustrated highly clumped distribution, which is believed to correspond with river flooding magnitudes and frequencies. To address the potential link between tree distribution and flooding within the River Murray, a hydrological analysis was conducted for Banrock Station using river flows at the South Australian border from 1900 to 2003. The amount of time growth stages for each species were inundated was found to be greatly reduced under regulated flows compared to natural flows. This has resulted in shifted localized regeneration patterns corresponding with E. camaldulensis' greater demand for inundation than E. largiflorens. Moderate magnitude flows have been most impacted by regulation, and consequently these are the very flows needed for floodplain tree population maintenance. Flowering and seed fall for E. camaldulensis and E. largiflorens were monitored at Banrock Station for 22 months to identify losses in reproductive potential resulting from tree decline. While seed viability was not affected by vigour, trees with visually reduced vigour were found to produce less fruit and had reduced seed fall, as well as a reduced rate of fruit development. Dendrochronological techniques were applied to floodplain trees. Age and size relationships could be established, implying that such techniques can be applied in South Australia to high quality sites. Growth responses within cohorts were similar and easily matched between individuals illustrating cyclic, but not necessarily seasonal correlations. This work verified the preferential selection of younger trees for dendroecological studies, and identified a relationship between on moderate flows and measurable girth expansion in both floodplain tree species.Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2004.
17
Nobbs, J. M. „The distribution and abundance of nematodes (especially the plant parasites) in the arid region of South Australia /“. Title page, contents and summary only, 1987. http://web4.library.adelaide.edu.au/theses/09PH/09phn744.pdf.
18
Hobson, Colin Desmond. „Environmental and socio-economic effects associated with the planting of Atriplex nummularia Lindl. (Oldman saltbush) in the Karoo“. Thesis, Rhodes University, 1991. http://hdl.handle.net/10962/d1001894.
Annotation:
This study examines the environmental and socio-economic effects associated with the planting of Atriplex nummularia Lindl. (Oldman saltbush) in the karoo. This is the first study of its kind on oldman saltbush and serves as an important scoping exercise in assessing the impact of saltbush on its surrounds and in identifying additional aspects which require investigation. The environmental parameters investigated include microclimatic effects, soil induced changes, salinity effects on the germination of selected karoo species and compositional changes in the indigenous plant community within a saltbush plantation. When compared to indigenous karoo plant species oldman saltbush is found to ameliorate soil temperatures and increase surface soil salinity (specifically sodium chloride), on an individual plant basis. Salinity is shown to have a differential effect on the germination of selected karoo shrubs. The indigenous plant community within a forty year old saltbush plantation is impoverished with both density of individuals and species richness being markedly reduced. Saltbush is identified as an unsuitable nurse plant for the majority of karoo shrubs. Farm size in relation to both actual and intended area established to saltbush is considered. The area of saltbush already established in the karoo is considered too insignificant to have any wide socio-economic impact. Farmers who intend planting large areas of their farms to saltbush are in the minority. It is those farmers who already have some saltbush planted, who intend planting more. Ecologically based management guidelines are presented, suggesting practices which minimize the detrimental effects of saltbush on soil salinity and the indigenous plant community. These guidelines are practical and in keeping with the overall objectives of optimum resource utilisation and the national grazing strategy for South Africa.
19
Tiver, Fleur. „Vegetation patterns of eastern South Australia : edaphic control and effects of herbivory /“. Title page, contents and abstract only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09pht623.pdf.
20
Holmes, P. M. „A comparative study of the seed bank dynamics of two congeneric alien invasive species“. Doctoral thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/17724.
Annotation:
Includes bibliographies.The unique vegetation in the lowlands of the fynbos biome is threatened by alien Acacia encroachment. The seed bank dynamics of the two most widespread invaders in the region, Acacia saligma and A. cyclops, was studied to elucidate those factors contributing most to their invasive success. This information was then used to assist in developing optimal control methods. On the basis of information available prior to this study, it was predicted that both species would have large, persistent seed banks in the so.il, and that seed bank processes would provide the - key to invasive success: namely, high seed longevity and heat-stimulated germination. Seed banks were monitored for several years following clearing of the parent stand, using either sites sampled in an earlier study, or sites providing chronosequences of clearing dates. Concurrently, a demographic study of the species' seed banks, including processes from seed rain through to seedling emergence and survival, was done in dense Acacia stands and in fynbos vegetation. Acacia saligma seed banks conformed to predictions, being large and persistent owing to high percentage viability and water-impermeable dormancy. Seed banks accumulate rapidly under dense stands and are "disturbance-coupled" as they have potentially high longevity unless stimulated to germinate by fire. Although A. cyclops seed banks also may be large and long-lived, they display variable percentage viability and dormancy, with the majority of a seed cohort surviving less than a year. Acacia cyclops seed banks do not respond to heat treatment and appear to be "disturbance-uncoupled".
21
Lenz, Tanja. „The effect of resource dynamics on invasive annual and native perennial grasses in grasslands of the mid-north of South Australia /“. Title page, table of contents and abstract only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09phl575.pdf.
22
Richardson, David Mark. „The ecology of invasions by Pinus (pinaceae) and Hakea (proteaceae) species, with special emphasis on patterns, processes and consequences of invasion in mountain fynbos of the southwestern Cape Province, South Africa“. Doctoral thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/18803.
Annotation:
The fire-prone mountain fynbos of the southwestern Cape Province of South Africa has been severely invaded by introduced trees and shrubs. These invasions have transformed fynbos shrublands to dense thickets of trees and shrubs in many parts of the region, thus disrupting various natural ecosystem processes. The ecology of invasions by species of Pinus and Hakea (the most successful genera) was studied using a series of natural experiments in conjunction with autecological studies. The study was divided into main four parts: (i) case studies to elucidate major patterns and processes of invasion; (ii) studies of the life history and population ecology of selected invaders; (iii) studies of the determinants of invasibility; and (iv) assessments of the consequences of invasion and of control programmes. Bibliography: pages 235-272.
23
Horsnell, Tara Kathleen. „Quantifying thresholds for native vegetation to salinity and waterlogging for the design of direct conservation approaches“. University of Western Australia. School of Environmental Systems Engineering, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0082.
Annotation:
A field-based project was undertaken to develop and test a mechanism which would allow for the correlation of the health of vegetation surrounding playa lakes in south-west Australia with the natural variation in salinity and waterlogging that occurs spatially and temporally in natural systems. The study was designed to determine threshold ranges of vegetation communities using moderately extensive data over short temporal periods which will guide the design of potential engineering solutions that manipulate hydrological regimes to ultimately conserve and protect native vegetation. A pair of playa lake ecosystems, surrounded by primary production land, was modelled with hydro-geological data collected from March 2006 to March 2007. The data was used to determine the hydroperiods of vegetation communities fringing playa lakes and provide insight into the areas and species that are most affected by extreme rainfall events which are hypothesised to have a significant, rapid deleterious effect on the ecosystems. The methodology was multi-faceted and included; a detailed topographical survey; vegetation surveys; hydrological and hydro-geological monitoring over a 12 month period. 4 The hydro-geological data and vegetation data was linked with the topographical survey at a high resolution for spatial analysis in a Geographic Information System (GIS) to determine the degree of waterlogging experienced by vegetation communities over the monitoring period. The study has found that the spatial and temporal variability of hydroperiods has been reduced by rising groundwater levels, a result of extensive clearing of native vegetation. Consequently populations are becoming extinct locally resulting in a shift in community composition. Extreme summer rainfall events also have a significant impact on the health of vegetation communities by increasing the duration of waterlogging over an annual cycle and in some areas expanding the littoral zone. Vegetation is most degraded at lower positions in the landscape where communities are becoming less diverse and dominated by salt tolerant halophytic species as a result of altered hydrological regimes. Some species appear to be able to tolerate groundwater depths of less than 2.0 m from the surface, however there are thresholds related to the duration at which groundwater is maintained at this depth. Potential engineering solutions include groundwater pumping and diverting water through drains to maintain sustainable hydroperiods for vegetation in areas with conservation value. The effectiveness and efficiency of the engineering solutions can be maximised by quantifying thresholds for vegetation that include sustainable durations of waterlogging. The study has quantified tolerance ranges to salinity and waterlogging with data collected over 12 months but species may be experiencing a transition period where they have 5 sustained irreversible damage that will result in their eventual mortality. With long-term monitoring, the methodology developed and tested in the study can be used to quantify the long-term tolerance ranges that are important for the application of conservation approaches that include engineering solutions.
24
Rea, Naomi. „The influence of water regime on the population ecology of two emergent macrophytes in South Australia /“. Title page, contents and summary only, 1993. http://web4.library.adelaide.edu.au/theses/09PH/09phr281.pdf.
25
Bougoure, Jeremy J. „The role of mycorrhizal fungi in nutrient supply and habitat specificity of the rare mycoheterotrophic underground orchid, Rhizanthella gardneri“. University of Western Australia. School of Plant Biology, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0076.
Annotation:
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 fungis 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.
26
Jenkins, Sommer. „Ecophysiological principles governing the zonation of puccinellia (Puccinellia ciliata) and tall wheatgrass (Thinopyrum ponticum) on saline waterlogged land in south-western Australia“. University of Western Australia. School of Earth and Geographical Sciences, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0133.
Annotation:
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.
27
Jackson, Tania. „Occurrence and variation of Endothiella eucalypti in Eucalyptus globulus plantations of south-western Australia and the influence of some biotic and abiotic factors on the response of the host to the pathogen /“. Access via Murdoch University Digital Theses Project, 2003. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20061129.132615.
28
Bleby, Timothy Michael. „Water use, ecophysiology and hydraulic architecture of Eucalyptus marginata (jarrah) growing on mine rehabilitation sites in the jarrah forest of south-western Australia“. University of Western Australia. School of Plant Biology, 2003. http://theses.library.uwa.edu.au/adt-WU2004.0004.
Annotation:
[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.
29
Kloot, P. M. (Peter Michael). „Studies in the alien flora of the cereal rotation areas of South Australia“. 1986. http://web4.library.adelaide.edu.au/theses/09PH/09phk655.pdf.
30
Kloot, P. M. (Peter Michael). „Studies in the alien flora of the cereal rotation areas of South Australia / P.M. Kloot“. 1985. http://hdl.handle.net/2440/20578.
Annotation:
Offprints of the author's articles insertedBibliography: v. 2, leaves 106-111
2 v. : ill. (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, Dept. of Agronomy, 1986
31
Kloot, Peter Michael. „Studies in the alien flora of the cereal rotation areas of South Australia“. Thesis, 1985. http://hdl.handle.net/2440/20578.
32
Kitt, Jörg Thomas. „Introduction of Aphidius rosae into Australia for biological control of the rose aphid (Macrosiphum rosae)“. 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phk608.pdf.
Annotation:
Bibliography: leaves 221-240. This thesis deals with the introduction of "Aphidius rosae" as a classical biological control agent into South-Eastern Australia. Appropriate host specificity tests are carried out. Laboratory experiments are also completed to gain a better understanding of the interactions between host and parasitoid in the field. The study aims to monitor the performance of the control agent in the Adelaide environment for the first two years after initial release. It is also planned to invent an experimental field technique to estimate the impact of the control agent on rose aphid populations.
33
Kitt, Jorg Thomas. „Introduction of Aphidius rosae into Australia for biological control of the rose aphid (Macrosiphum rosae) / by Jorg Thomas Kitt“. 1996. http://hdl.handle.net/2440/18781.
Annotation:
Bibliography: leaves 221-240.viii, 240, [13] leaves : ill. (some col.), maps ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
This thesis deals with the introduction of "Aphidius rosae" as a classical biological control agent into South-Eastern Australia. Appropriate host specificity tests are carried out. Laboratory experiments are also completed to gain a better understanding of the interactions between host and parasitoid in the field. The study aims to monitor the performance of the control agent in the Adelaide environment for the first two years after initial release. It is also planned to invent an experimental field technique to estimate the impact of the control agent on rose aphid populations.
Thesis (Ph.D.)--University of Adelaide, Dept. of Crop Protection, 1997
34
Kitt, Jorg Thomas. „Introduction of Aphidius rosae into Australia for biological control of the rose aphid (Macrosiphum rosae) / by Jorg Thomas Kitt“. Thesis, 1996. http://hdl.handle.net/2440/18781.
Annotation:
Bibliography: leaves 221-240.viii, 240, [13] leaves : ill. (some col.), maps ; 30 cm.
This thesis deals with the introduction of "Aphidius rosae" as a classical biological control agent into South-Eastern Australia. Appropriate host specificity tests are carried out. Laboratory experiments are also completed to gain a better understanding of the interactions between host and parasitoid in the field. The study aims to monitor the performance of the control agent in the Adelaide environment for the first two years after initial release. It is also planned to invent an experimental field technique to estimate the impact of the control agent on rose aphid populations.
Thesis (Ph.D.)--University of Adelaide, Dept. of Crop Protection, 1997
35
Vivian, Lyndsey Marie. „Variation in fire response traits of plants in mountainous plant communities of south-eastern Australia“. Phd thesis, 2010. http://hdl.handle.net/1885/151436.
Annotation:
In fire-prone ecosystems, plant species exhibit a range of traits which allow them to persist under certain fire regimes. Two critical traits are resprouting and regeneration from seed. Resprouters and seeders can coexist within plant communities, but their relative proportion varies. This research investigated variation in patterns of community composition, in terms of fire response traits, across a mountainous region of south-eastern Australia. The relative importance of fire regimes, habitat, vegetation cover and resource gradients in influencing these patterns was tested. Associations between leaf traits and fire response types were also explored to investigate whether traits related to fire persistence can be considered as part of a broader spectrum of plant ecological strategies, and assist in explaining landscape patterns. In January 2003 unplanned fires burned through the region, creating the opportunity to investigate the responses of locally occurring plants. An initial study of observed field data demonstrated that some species varied in their response between sites. Furthermore, observed responses often differed from those reported in a fire response trait database. As such, the decision was taken to use observed site-specific data on fire response traits where possible to analyse community composition across the region. Data were subsequently collated from five post-fire surveys conducted across 284 sites in the study area. Resprouting was a dominant response of species in the region. However, woody obligate seeders, although infrequent, were often structurally important. Within-species variation was identified, with variability in post-fire seed regeneration particularly evident in trees. The results unexpectedly identified 'dataset' as the factor most strongly associated with the observed patterns, raising important questions about the use of data collated from different sources. Obligate resprouters were favoured at sites burned with no short intervals between fires, whereas several woody obligate seeding types were in higher proportions at sites burned with one or two short intervals. This suggests that some degree of fire is required for obligate seeder persistence. However, the possibility that woody obligate seeders had already been eliminated from the region prior to this study, due to short inter-fire intervals, could not be discounted. Significant differences between habitats were identified, with woody obligate seeders found in high proportions on rock outcrops and in wet grasslands. However, trends in the proportions of fire response types across habitats could not be reconciled with trends in habitat characteristics such as canopy height and understorey cover. Understorey cover was negatively associated with seeders and facultative resprouters, suggesting an important influence of competition post-fire. Leaf trait comparisons showed that facultative resprouters differed from obligate seeders and obligate resprouters, indicating that this strategy requires an investment into rapid acquisition of resources and fast growth to compete. Differences in leaf traits in species with a canopy seed bank were also identified, raising some important considerations regarding approaches to classifying species by fire response traits. This research illustrates the value of considering the relative importance of fire in relation to other factors for developing a thorough understanding of the processes governing community composition in fire-prone ecosystems. Importantly, the approaches taken in this thesis also revealed a range of issues regarding the application of trait data, which are discussed in relation to trait-based ecological research and management.
36
Frost, William E. „The ecology of cereal rust mite Abacarus hystrix (Nalepa) in irrigated perennial dairy pastures in South Australia / by William E. Frost“. Thesis, 1995. http://hdl.handle.net/2440/18667.
37
Hogbin, Patricia May. „Conservation outcomes arising from research into the population genetics, taxonomy and reproductive ecology of the endangered plant Zieria prostrata“. Phd thesis, 2001. http://hdl.handle.net/1885/146021.
38
Thomas, L. M. „Regolith-landforms and plant biogeochemical expression of buried mineralisation targets in the northern Middleback Ranges, (“Iron Knob South”) South Australia“. Thesis, 2011. http://hdl.handle.net/2440/97938.
Annotation:
This item is only available electronically.South of the town Iron Knob on the northern Eyre Peninsula, a tenement scale plant biogeochemical survey and regolith-landform mapping, combined to define areas with elevated Cu, Zn and Au contents that are worthy of follow-up exploration. Plant biogeochemistry was conducted within a 6 Km2 area with 1 Km spacing between each E-W trending transect and 200 m spacing between each sample. A regolith-landform map presents the distribution of regolith materials and associated landscape processes to help constrain geochemical dispersion. A Philips XL30 SEM provided insight into how the plants uptake certain elements and distribute them within the organs structure. Two zones of elevated trace metals (e.g. Cu, Au and Zn) were defined either side of a NW-SE structure crossing over the N-S trending “Katunga‟ ridge. Both targets were located on similar regolith-landform units of sheet-flood fans and alluvial plains. Copper and Zn results were best represented by the western myall species while the bluebush species was best at detecting Au. A follow up study targeting the NW-SE structure with closer sample spacing is recommended in further constraining drilling targets. For the tenement holding company, Onesteel Ltd, these results are significant as they define two new areas of interest for possible IOCG mineralisation. For research purposes the results confirm that plant biogeochemistry can be used as an effective tool for detecting mineralisation along buried structures providing the use of the right species in the area.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2011
39
Ladd, Brenton M. „The intensity of competitive interactions as a function of fertility, in Mediterranean-type old fields in South Australia / Brenton Ladd“. 2003. http://hdl.handle.net/2440/21985.
Annotation:
"April 22, 2003"Bibliography: leaves 131-147.
147 leaves : ill., 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Studies the establishment of tree seedlings in Mediterranean-type oldfields in South Australia to test for a correlation between habitat fertility and the intensity of competition. Also investigates whether resource competition and invertebrate herbivory are confounded with each other. Testing for correlation was carried out using a quantitative literature review in combination with field and glasshouse experiments. Results suggest that direct effects,and indirect effects may be heavily confounded, and that a positive correlation between fertility and the intensity of competition is most probable when a phenomenological definition of competition is used.
Thesis (Ph.D.)--University of Adelaide, School of Environmental Engineering, 2003
40
Ladd, Brenton Mark. „The intensity of competitive interactions as a function of fertility, in Mediterranean-type old fields in South Australia / Brenton Ladd“. Thesis, 2003. http://hdl.handle.net/2440/21985.
Annotation:
"April 22, 2003"Bibliography: leaves 131-147.
147 leaves : ill., 30 cm.
Studies the establishment of tree seedlings in Mediterranean-type oldfields in South Australia to test for a correlation between habitat fertility and the intensity of competition. Also investigates whether resource competition and invertebrate herbivory are confounded with each other. Testing for correlation was carried out using a quantitative literature review in combination with field and glasshouse experiments. Results suggest that direct effects,and indirect effects may be heavily confounded, and that a positive correlation between fertility and the intensity of competition is most probable when a phenomenological definition of competition is used.
Thesis (Ph.D.)--University of Adelaide, School of Environmental Engineering, 2003
41
Mensforth, Lisa. „Water use strategy of Melaleuca halmaturorum in a saline swamp / by Lisa Jane Mensforth“. Thesis, 1996. http://hdl.handle.net/2440/18922.
Annotation:
Bibliography: leaves 214-239.xviii, 239 leaves : ill., maps ; 30 cm.
The aim of this study is to identify the water use strategy of Malaleuca halmaturorum in response to salinity and waterlogging in the root zone and through this quantify groundwater use and the role of M. halmaturorum in the water balance. The water use strategy of M. halmaturorum is investigated in the saline ephemeral swamps of South Eastern South Australia to understand the effect of the wetland vegetation on the groundwater balance and the survival mechanisms and reasons for the decline in health of M. halmaturorum in the region.
Thesis (Ph.D.)--University of Adelaide, Dept. of Botany, 1997
42
Nobbs, J. M. (Jacqueline Mary). „The distribution and abundance of nematodes (especially the plant parasites) in the arid region of South Australia / by J.M. Nobbs“. 1987. http://hdl.handle.net/2440/21590.
Annotation:
Includes bibliographyii, 84 leaves, [7] leaves of plates : ill. (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Pathology, 1987
43
Nobbs, J. M. (Jacqueline Mary). „The distribution and abundance of nematodes (especially the plant parasites) in the arid region of South Australia / by J.M. Nobbs“. Thesis, 1987. http://hdl.handle.net/2440/21590.
44
Rea, Naomi. „The influence of water regime on the population ecology of two emergent macrophytes in South Australia / by Naomi Rea“. Thesis, 1993. http://hdl.handle.net/2440/20591.
Annotation:
Bibliography: leaves 103-120.1 v. (various pagings) : ill. (some col.), maps ; 30 cm.
Species interactions are dependent on the water regime, which affects the relative allocation to below (sediment resource acquisition) and above ground (C acquisition) parts. At shallow and regularily exposed sites, Baumea is the superior competitor. In Hacks and Bool Lagoon, South Australia, changing distribution patterns occur in deep and permanently flooded conditions, where Baumea dies back, paving the way for Triglochin to passively take it's place.
Thesis (Ph.D.)--Dept. of Botany, University of Adelaide, 1993
45
Bité, Juanita Saulé. „The ecology and demography of the introduced macroalga Undaria pinnatifida (Harvey) Suringar in Port Phillip Bay, Victoria, Australia“. Thesis, 2001. https://vuir.vu.edu.au/17923/.
Annotation:
Information from this thesis provides a critical understanding of the environmental
factors that influence the growth and reproduction of different life stages of Undaria
pinnatifida in Port Phillip Bay. Such information is important towards understanding
the potential spread of this invasive species and may provide insight into methods that
can be used to limit its expansion in southern Australian waters.
In 1996 Undaria pinnatifida (Harvey) Suringar (Laminariales: Phaeophyta) was found
growing in coastal waters of Port Phillip Bay, Victoria, Australia. Undaria pinnatifida
is an opportunistic colonizer capable of high rates of reproduction and fast growth
rates producing high density populations. It is the dominant macroalgal species at the
site of invasion during winter and spring and has the potential for further spread from
its current distribution in the northern part of Port Phillip Bay. This is the first in Australia examining the effects of temperature, nitrogen concentration, photon flux
density and photoperiod on germination of zoospores, gametophyte growth and
reproduction of U. pinnatifida in culture. Information on its recruitment, growth and
reproductive capacity in the field is also presented for the first time for a population Australia.
46
Carne, Vanessa Lynne. „Ecology of Mediterranean snails in Southern Australian agriculture : a study of Cernuella virgata and Cochlicella acuta on the Yorke Peninsula / Vanessa L. Carne“. 2003. http://hdl.handle.net/2440/22109.
Annotation:
"August 2003."Includes bibliographical references (leaves 294-333)
2 v. (xxxi, 333 leaves) ; ill. (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, School of Agriculture and Wine, Discipline of Plant and Pest Science, 2005
47
Tiver, Fleur. „Vegetation patterns of eastern South Australia : edaphic control and effects of herbivory / by Fleur Tiver“. Thesis, 1994. http://hdl.handle.net/2440/21519.
48
Nicolson, K. (Kym). „Spatial and temporal patterns of herbaceous species at Middleback Station, South Australia / by Kym P. Nicolson“. 1985. http://hdl.handle.net/2440/20599.
Annotation:
Bibliography: p. [i.e. leaves] 267-277277 p. [i.e. leaves], [4] leaves of plates : ill. (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, 1986
49
Nicolson, K. (Kym). „Spatial and temporal patterns of herbaceous species at Middleback Station, South Australia / by Kym P. Nicolson“. Thesis, 1985. http://hdl.handle.net/2440/20599.
50
Stamoulis, F. F. „A comparison of regional plant biogeochemical and soil geochemical expressions of buried mineralization in the Olympic Dam region, South Australia“. Thesis, 2011. http://hdl.handle.net/2440/97929.
Annotation:
This item is only available electronically.Biogeochemical methods can be employed to assist in detecting buried ore deposits. Plant roots can penetrate the bedrock and therefore, as a result of testing their leaves can give a good indication of the buried mineralization in an area. The aim of this study was to support or challenge the findings from the study that was conducted by Wang et al. (1999). It also aimed to compare the biogeochemistry results with traditional soil analysis. Mulga (Acacia aneura) and Pearl Bluebush (Maireana sedifolia) leaves as well as soil samples were collected and analysed from eighteen different locations at the Olympic Dam (Roxby Downs) region. The analysis of these plants and soils detected a range of elements including the ones that were relevant to this study (mercury, copper and gold). The vegetation, bulk analysis and partial leach results of this study did not show a similar pattern of mercury, copper and gold concentrations to the results from the Wang et al. (1999) study. Giving this information, this study cannot support the findings from the Wang et al. (1999) study. An important finding of this study was that sample VEG 007 recorded the highest concentrations in the majority of the elements and as a result the area may require further investigation. In addition, vegetation and soil samples that were taken from approximately 5 km south, approximately 10 km south and approximately 15 km north east of Olympic Dam region showed some promising results and as a result these areas may require further investigation. This study showed that biogeochemistry may be useful in locating potential mineral deposits.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2011