Past research suggests that social organisation in Australian rodent species is determined by the predictability of resources in the environment (Happold 1976a). Notomys alexis (the spinifex hopping mouse or tarrkawarra) is widely distributed throughout the Australian arid-zone (Breed 1998a; Watts & Aslin 1981). Large groups of animals have been found sharing burrows in the wild and laboratory observations suggest that the species is highly social (Happold 1976a; Stanley 1971). A closely related species, Notomys mitchelli (Mitchell’s hopping mouse or pankot) is relatively common throughout the southern semi-arid zone (Watts 1998a; Watts & Aslin 1981). Much less is known about N. mitchelli; field studies have been subject to low recapture rates and few laboratory studies have involved this species (Baverstock 1979; Cockburn 1981a; Crichton 1974). Following Happold (1976a), it was hypothesised that the socio-ecology of N. mitchelli will be qualitatively different to that of N. alexis. Studying wild populations of Notomys mitchelli in the Middleback Ranges, South Australia and N. alexis outside the desert township of Roxby Downs, S.A., this research aimed to describe the socio-ecology of these species, with reference to the predictability of their environments. Uniquely, bioclimatic modelling of the species’ known distributions was also conducted to confirm that the study’s underlying assumption that the two rodents inhabit essentially different environments was correct. These studies were complemented by the observation of captive groups of N. alexis. This work confirmed that the habitats of Notomys mitchelli and N. alexis are distinct; the more arid habitat of N. alexis is subject to greater environmental fluctuations than that of the semi-arid dwelling N. mitchelli. Contrary to expectations, however, observation of free-living animals characterised N. mitchelli social groups as highly unstable; while particular individuals remained in the population for long periods, many animals appeared to be transients. Further, burrow groups appeared to be much smaller than predicted by Happold (1976a), and based on loose aggregations of male animals rather than small groups of females. While decidedly social in the laboratory, free-living N. alexis lived in groups no bigger than N. mitchelli and these groups were equally ephemeral in constitution. Moreover, free-living N. alexis appeared to utilise activity areas that were no larger than those used by N. mitchelli, despite occupying a more unpredictable and apparently less well-resourced habitat. As a whole, this research represents a comprehensive examination of the principal behavioural theory commonly applied to Australian native rodent species, untested since its publication three decades ago. From the data collected during this work, it cannot be said that the environmental predictability hypothesis for native rodent social organisations as proposed by Happold (1976a) is adequate to differentiate the social behaviour of these semi-arid and arid-dwelling species. Instead, it is suggested that, while both N. mitchelli and N. alexis are undoubtedly socially tolerant, predation and/or parasite load, driving burrowing behaviour, has a greater influence on the social behaviour of free-living rodent populations than habitat predictability. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1373743 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009

The study was conducted in Eastern Cape Province to 1) investigate local people’s knowledge and perceptions on Euryops floribundus and 2) landscape distribution and effect of Euryops floribundus on herbaceous vegetation and soil. A total of 90 households who own livestock were randomly selected from the three communal areas, namely; Tsengiwe, Upper Mnxe and Manzimdaka for household surveys and group discussions. For landscape study, a total of about 5 ha of land were selected at Upper Mnxe communal area. Selection criteria included the presence of E. floribundus and different landscape gradients. A total of four 50mx50 plots were marked along the landscape gradients: Bottom, Middle, and Upper Slope and upland positions. To study the effect of E. floribundus invasion on the herbaceous vegetation and soil, a total of 4 ha communal land was selected in an accessible area which had a largely flat terrain. The area was selected to have adjacent sites with no invasion (< 5% shrub cover), light (5-15% shrub cover), moderate (>15-35) and heavy invasions (>35% shrub cover) of E. floribundus. The average household size in the study area was 6.8± 0.7. All people in the three communal areas unanimously ranked sheep as the most important species for their livelihood, but the ranking of cattle and goat varied among the communal areas. All elder groups agreed that Europs floribundus decreases both the quantity and quality of herbaceous forage as well as livestock production. Moreover, invaded patches create more bare areas which are responsible for the loss of top fertile soils and the formation of rills and gullies. The result showed that the total density of E. floribundus significantly increased from the topland (2301 plants ha-1) moving to the bottomland (4888 plants ha-1). Canopy cover was significantly lowest in the topland (17.9%), but the remaining gradients had similar cover. Grass dry matter yield was higher in the bottomlands and sloppy gradients than the toplands. Soil organic carbon was significantly higher (P<0.05) in the flat than the sloppy terrain. Soils from higher elevations (toplands and upper sloppy) had significantly higher N than the lower elevations (bottomlands and Middle sloppy). The lowest dry matter was observed at low invasion and non-invaded sites. Soil chemical properties were generally different from all density levels. In conclusion, E. floribundus encroachment was found to be major cause of decline in the peoples’ livelihood because as this reduces the vegetation diversity and livestock production, both of which are the major of their livelihoods.

Doctor of Philosophy / Department of Agronomy / Walter H. Fick / Sericea lespedeza [Lespedeza cuneata (Dumont) G. Don] is a rangeland weed of the tallgrass prairie of Kansas. Experiments were carried out during the 2001-2003 growing seasons (June-November) to examine the relationship between sericea lespedeza and other rangeland species, wildlife use and dispersal of sericea lespedeza propagules, and the relationship between sericea lespedeza stubble height and utilization by livestock. Sericea lespedeza cover was positively correlated with violet lespedeza (r=0.25) [Lespedeza violacea (L.) Pers.], heath aster (Aster ericoides L.) (r=0.23) and total forb cover (r=0.56). Sericea lespedeza composition was negatively correlated with big bluestem (Andropogon gerardii Vitman.) (r=-0.27) and sideoats grama [Bouteloua curtipendula (Michx. Torr.)] (r=-0.27) composition and positively correlated with western ragweed (Ambrosia psilostachya D.C.) (r=0.21) and violet lespedeza (r=0.36) composition. Sericea lespedeza density was inversely related to forb species richness on all sites. On half the sites, there was also an inverse relationship between grass species richness and sericea lespedeza density. Grazed sites had less difference in grass species richness between high and low levels of sericea lespedeza densities. There was no evidence of an ecological threshold to the detriment of species richness with increasing sericea lespedeza density. Cattle digestive processes did not affect sericea lespedeza germination. Quail digestive processes enhanced germination of the few seeds that were excreted. Quail diet selection was investigated with a field study. Five out of 49 crops collected contained seed classified as sericea lespedeza. None of these seeds germinated in the greenhouse. Both cattle and quail could potentially disperse sericea lespedeza seed, but voluntary consumption appears to be low for both species, at least during November when other food is available. An height-weight table estimating percent utilization for various grazed and ungrazed heights of sericea lespedeza was constructed. Coefficient of determination values were greater than 0.85 between plant height and weight, indicating that the heightweight method was appropriate for estimating sericea lespedeza utilization. Using additional regression analysis, a chart for estimating forage from percent of plants grazed was constructed.

Accompanying CD-ROM inside back cover, includes Appendices. Bibliography: leaves 242-266. This thesis examines the effects on vegetation at selected sites in northern South Australia of excluding various herbivores over a four and a half year period and of two intense but controlled grazing pulses over a six month period followed by an 18 month recovery period in a dune-swale land system. These changes are compared with changes recorded over an 11-year period at the Olympic Dam mine site. It found that short-term changes in vegetation revealed by ordination of periodical cover, density and species richness, are attributable to the periodicity of rainfall and that, under present grazing regimes, rainfall effects override grazing effects. Differences between the effects of sheep and cattle hoof damage are worthy of further investigation, as is the impact of kangaroo grazing. These two factors may have important implications for the management of Australian rangelands. System requirements for accompanying CD-ROM: IBM compatible computer with Pentium processor or higher and Windows 95, 98 or NT ; 4 MB or RAM. Other software: Acrobat Adobe Reader.

Bibliography: leaves 308-333.

Accompanying CD-ROM inside back cover, includes Appendices. / Bibliography: leaves 242-266. / System requirements for accompanying CD-ROM: IBM compatible computer with Pentium processor or higher and Windows 95, 98 or NT ; 4 MB or RAM. Other software: Acrobat Adobe Reader. / xv, 266 p. : maps, charts ; 30 cm. + 1 CD-ROM (4 3/4 in.) / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis examines the effects on vegetation at selected sites in northern South Australia of excluding various herbivores over a four and a half year period and of two intense but controlled grazing pulses over a six month period followed by an 18 month recovery period in a dune-swale land system. These changes are compared with changes recorded over an 11-year period at the Olympic Dam mine site. It found that short-term changes in vegetation revealed by ordination of periodical cover, density and species richness, are attributable to the periodicity of rainfall and that, under present grazing regimes, rainfall effects override grazing effects. Differences between the effects of sheep and cattle hoof damage are worthy of further investigation, as is the impact of kangaroo grazing. These two factors may have important implications for the management of Australian rangelands. / Thesis (Ph.D.)--University of Adelaide, Dept. of Environmental Biology, 2002