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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Role of mycorrhizas in the regeneration of arid zone plants / by Peter Allan McGee

McGee, P. A. (Peter Allan) January 1987 (has links)
Bibliography: leaves 146-152 / 152 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--Dept. of Plant Pathology, Waite Agricultural Research Institute, University of Adelaide, 1987
22

Causes and ecological consequences of the Spencer Gulf seagrass dieback / Stephanie Seddon.

Seddon, Stephanie January 2000 (has links)
Includes bibliographical refe / xiv, 171 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates the causes and consequences of a sudden dieback of intertidal and shallow subtidal seagrasses along 95 km of the eastern coast of Spencer Gulf, South Australia. Concludes with a conceptual model specific to shallow waters of Spencer Gulf where climatological extremes and geological processes are the main environmental factors influencing the processes of seagrass dieback and subsequent recolonisation and succession. / Thesis (Ph.D.)--Adelaide University, Dept. of Environmental Biology, 2001
23

The role of shallow seagrass meadows as habitat for fish / by Roderick Martin Connolly.

Connolly, R. M. January 1994 (has links)
Bibliography : leaves 293-304. / xii, 304 leaves : ill., maps ; 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 Zoology, 1994
24

The effect of resource dynamics on invasive annual and native perennial grasses in grasslands of the mid-north of South Australia / Tanja Lenz. / Resource dynamics & grass abundance in mid-north grasslands of South Australia

Lenz, Tanja I. January 2004 (has links)
"July 2004." / Bibliography: leaves 120-136. / vii, 136 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. / Investigates the effects of soil moisture dynamics on the growth and interactions between invasive annual grasses and native perennial grasses in the mid-north of South Australia. At most sites annual grass abundance was positively correlated with rainfall, soil moisture after rainfall and higher soil productivity. Perennial grass abundance was negatively correlated with annual grass abundance and soil moisture after rainfall, and was weakly positively correlated with percentage summer rainfall, elevation, radiation, gravel and slope. Overall perennial grasses responded little to the environmental variables investigated, but strongly to annual grass abundance, while for annual grasses soil moisture was the driving variable. / Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Environmental Biology, 2004
25

Effects of man on the vegetation in the national parks of South Australia

Mattiske, Elizabeth M. January 1975 (has links) (PDF)
Volume 2 consists almost entirely of maps. Includes index of plant species. Bibliography: p. 227-242 (v.1) Floristic and structural changes in native vegetation resulting from man's influence are examined in detail in 5 South Australian parks. The results permit the clear delineation and segregation of those patterns determined by man's activities, from those induced by soil and topographic features.
26

The role of the reintroduction of Greater Bilbies (Macrotis lagotis) and Burrowing Bettongs (Bettongia Lesueur) in the ecological restoration of an arid ecosystem: foraging diggings, diet, and soil seed banks.

Newell, Janet January 2009 (has links)
Arid Recovery, a fenced reserve free of feral predators in arid South Australia, has successfully reintroduced two critical weight range (CWR) mammals, greater bilbies (Macrotis lagotis) and burrowing bettongs (Bettongia lesueur) to facilitate the restoration of arid Australian ecosystems. This thesis evaluates the ecological roles of these reintroduced species and their relationship to ecosystem functioning and the restoration of these ecosystems. Surveys of foraging diggings and soil seed banks, and dietary analysis were used to measure impacts of these species on three main habitats within the Reserve. The results showed that bilbies and bettongs have three major roles in ecosystem functioning: consumers, ecosystem engineers, and dispersers of seeds and fungi. Both bilbies and bettongs were omnivorous, though their diets were distinctly different, with the bilbies focused more on invertebrates and seeds, while the bettongs consumed a greater proportion of coarser plant materials. The seed portion of the diets of both species during 2003-04 differed from a similar study three years previously, shortly after the animals had been reintroduced to Arid Recovery in 2000- 01. During 2003-04, the bilbies consumed a lower proportion of seeds of species of grasses and more of forbs, while seed consumption by bettongs narrowed to be almost exclusively the seeds of shrubs. The number of bilby and bettong diggings varied significantly both spatially and temporally, with averages of 7,530 ± 820 diggings ha-1 in Dunes, 10,560 ± 980 diggings ha-1 in Mulga, and 7,120 ± 610 diggings ha-1 in Swale. This resulted in an average of 2 to 3% disturbance of soil surface area, which is similar to or higher than reported for other Australian or overseas semi-fossorial species. The temporal variation in rates of digging was correlated with minimum daily temperatures and rainfall but not moonlight. This variation was also correlated with counts of bilby but not bettong tracks, suggesting that the temporal variability of diggings was related to levels of bilby activity. The persistence of bilby and bettong diggings differed between the three habitat types, with the majority of the diggings in the Mulga (94%) and Swale (87%) persisting for over 12 months, while Dune diggings filled much faster, with only 15% persisting over 12 months. These diggings were shown to accumulate and bury seeds and litter, and, under some conditions, enhance germination. The seeds of two plant species, the annual grass, Dactyloctenium radulans, and the shrub, Enchylaena tomentosa, germinated from bilby faecal pellets, and over a third of bilby faecal pellets contained fungal spores. Therefore bilbies have the potential to be dispersers of both seeds and fungi. All three major roles of the bilbies and bettongs in ecosystem functioning (consumers, ecosystem engineers, and dispersers of seeds and fungi) have the potential to affect the flows of organic, soil and water resources, and therefore vegetation structure and overall productivity. Soil seed bank densities differed between areas with and without bilbies and bettongs. However, the heterogeneity of the system made it difficult to confidently relate these differences to any particular effects of the bilbies and bettongs. Both bilbies and bettongs were able to locate and dig seeds buried 20 cm deep, and the caches of seed-harvester ants. Experiments showed that in areas of high digging density, 71 to 94% of seed rain accumulated and became buried in diggings. Since bilbies and bettongs have the potential to use buried seed resources, they have the potential to significantly affect soil seed banks through their consumption of seeds, redistribution of seeds through their digging activities and their interactions with other granivorous species. This study is a first step towards understanding the roles of reintroducing CWR mammals to arid ecosystems. Possible longer term effects of these reintroductions will depend on suitable regulation of animal numbers, and climatic patterns, as restorative effects of diggings would be greatest during periods of good rainfall, whereas droughts would slow restorative processes. Although the results of this research are unique for Arid Recovery, the principles of evaluating all major ecological roles of reintroduced species and their interactions with their environment could provide guidance for other reintroductions. These interactions are complex and would require longer-term studies over a range of conditions and locations to further understand the role of reintroducing CWR mammals to ecological restoration. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1348600 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009
27

The role of the reintroduction of Greater Bilbies (Macrotis lagotis) and Burrowing Bettongs (Bettongia Lesueur) in the ecological restoration of an arid ecosystem: foraging diggings, diet, and soil seed banks.

Newell, Janet January 2009 (has links)
Arid Recovery, a fenced reserve free of feral predators in arid South Australia, has successfully reintroduced two critical weight range (CWR) mammals, greater bilbies (Macrotis lagotis) and burrowing bettongs (Bettongia lesueur) to facilitate the restoration of arid Australian ecosystems. This thesis evaluates the ecological roles of these reintroduced species and their relationship to ecosystem functioning and the restoration of these ecosystems. Surveys of foraging diggings and soil seed banks, and dietary analysis were used to measure impacts of these species on three main habitats within the Reserve. The results showed that bilbies and bettongs have three major roles in ecosystem functioning: consumers, ecosystem engineers, and dispersers of seeds and fungi. Both bilbies and bettongs were omnivorous, though their diets were distinctly different, with the bilbies focused more on invertebrates and seeds, while the bettongs consumed a greater proportion of coarser plant materials. The seed portion of the diets of both species during 2003-04 differed from a similar study three years previously, shortly after the animals had been reintroduced to Arid Recovery in 2000- 01. During 2003-04, the bilbies consumed a lower proportion of seeds of species of grasses and more of forbs, while seed consumption by bettongs narrowed to be almost exclusively the seeds of shrubs. The number of bilby and bettong diggings varied significantly both spatially and temporally, with averages of 7,530 ± 820 diggings ha-1 in Dunes, 10,560 ± 980 diggings ha-1 in Mulga, and 7,120 ± 610 diggings ha-1 in Swale. This resulted in an average of 2 to 3% disturbance of soil surface area, which is similar to or higher than reported for other Australian or overseas semi-fossorial species. The temporal variation in rates of digging was correlated with minimum daily temperatures and rainfall but not moonlight. This variation was also correlated with counts of bilby but not bettong tracks, suggesting that the temporal variability of diggings was related to levels of bilby activity. The persistence of bilby and bettong diggings differed between the three habitat types, with the majority of the diggings in the Mulga (94%) and Swale (87%) persisting for over 12 months, while Dune diggings filled much faster, with only 15% persisting over 12 months. These diggings were shown to accumulate and bury seeds and litter, and, under some conditions, enhance germination. The seeds of two plant species, the annual grass, Dactyloctenium radulans, and the shrub, Enchylaena tomentosa, germinated from bilby faecal pellets, and over a third of bilby faecal pellets contained fungal spores. Therefore bilbies have the potential to be dispersers of both seeds and fungi. All three major roles of the bilbies and bettongs in ecosystem functioning (consumers, ecosystem engineers, and dispersers of seeds and fungi) have the potential to affect the flows of organic, soil and water resources, and therefore vegetation structure and overall productivity. Soil seed bank densities differed between areas with and without bilbies and bettongs. However, the heterogeneity of the system made it difficult to confidently relate these differences to any particular effects of the bilbies and bettongs. Both bilbies and bettongs were able to locate and dig seeds buried 20 cm deep, and the caches of seed-harvester ants. Experiments showed that in areas of high digging density, 71 to 94% of seed rain accumulated and became buried in diggings. Since bilbies and bettongs have the potential to use buried seed resources, they have the potential to significantly affect soil seed banks through their consumption of seeds, redistribution of seeds through their digging activities and their interactions with other granivorous species. This study is a first step towards understanding the roles of reintroducing CWR mammals to arid ecosystems. Possible longer term effects of these reintroductions will depend on suitable regulation of animal numbers, and climatic patterns, as restorative effects of diggings would be greatest during periods of good rainfall, whereas droughts would slow restorative processes. Although the results of this research are unique for Arid Recovery, the principles of evaluating all major ecological roles of reintroduced species and their interactions with their environment could provide guidance for other reintroductions. These interactions are complex and would require longer-term studies over a range of conditions and locations to further understand the role of reintroducing CWR mammals to ecological restoration. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1348600 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009
28

Spatiotemporal variation of macroalgal communities of southern Fleurieu Peninsula, South Australia / by Gregory James Collings.

Collings, Gregory James January 1996 (has links)
Bibliography: leaves 191-225. / 2 v. : ill. (some col.), maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The temporal dynamics of eight subtidal mixed macroalgal communities were quantified. The results were discussed in terms of the implications for sampling programs in the future and the reliability of previous work. / Thesis (Ph.D.)--University of Adelaide, Dept. of Botany, 1997?
29

The role of disturbance in the ecology of biofilms in the River Murray, South Australia / by Adrienne Burns.

Burns, Adrienne, 1971- January 1997 (has links)
Copy of author's previously published article inserted. / Bibliography: leaves 198-217. / 249 leaves : ill., maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis explores the impact of sustained disturbances on the ecology of algal dominated biofilms in the Lower River Murray, South Australia. It focuses on the physical effects of regulation through changes to the light environment and water level regime, and the local effects of grazing. The nutritional signficance of biofilms for the abundant populations of prawns and shrimps in the Lower Murray is also examined. / Thesis (Ph.D.)--University of Adelaide, Dept. of Zoology, 1997?
30

Aspects of the autecology of the pearl bluebush, Mairenana sedifolia / by Noelene Joy Wotton.

Wotton, Noelene Joy January 1993 (has links)
Bibliograpy : leaves 267-288. / xi, 288 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. / Thesis (Ph.D.)--University of Adelaide, Dept. of Botany, 1994?

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