Browsing by Author "Thomas, Alicia Jessica"

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    Factors affecting the emergence times of seven sympatric insectivorous bat species
    (2011) Thomas, Alicia Jessica; Jacobs, David S
    The onset of activity in animals restricted to being active for only part of the day, is one of the most fundamental aspects of their biology. Onset of activity is likely subject to several factors including presence/absence of predators and the vagaries of environmental conditions at the time of emergence. The aim of my study was to test several hypotheses accounting for differing emergence times amongst sympatric insectivorous bat species.
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    Using Sporormiella to track herbivore biomass within the Hluhluwe-Imfolozi game reserve
    (2007) Thomas, Alicia Jessica; Gillson, Lindsey; Bond, William J
    Historical fossilised spores of Sporomiella, a coprophilous fungus that only grows on the dung of herbivores. has been used to infer unknown herbivore abundances or biomass and identity periods of mega-herbivore extinction in the palaeo-record. ln Africa. however. mega-herbivores are still extant and there is therefore a unique opportunity to calibrate Sporomiella abundance against known herbivore biomass. This study was carried out within the Hluhluwe-lmfolozi Game Reserve, KwaZulu-Natal South Africa (28°00'-28°26'S. 31°43'-32°00'E. Fig 2(a) and (6)). We evaluated the relationship between Sporomiella concentration and herbivore abundance. as indicated by total dung abundances. We investigated three aspects of this relationship: [1] the relationship between Sporomiella abundance and total herbivore dung abundance. [2] the relationship between Sporomiella and individual herbivore species, where we also divided all the herbivores into Mega-herbivores and Meso-herbivores to determine their relationship with Sporomiella densities. [3] finally, we tested the differences between the regions of the reserve by comparing the different areas of the park, as each system has its own unique drivers (Hluhluwe (fire driven), Imfolozi (herbivore driven) and the corridor (fire and herbivore driven)), with the concentration of Sporomiella. We found no significant relationships between Sporomiella concentration and total herbivore dung abundances, which suggests that the fungus may be selectively growing on certain herbivore species rather than on all herbivore dung and / or the amount of dung for each species is not accurately reflected by dung counts [because amount of dung per species isn't accurately reflected by dung counts?]. This isn't reflected in clung counts. When the sites that had zero Sporomiella were excluded from the analysis. Sporomiella concentration was significantly related to elephant and white rhino dung abundance, which could be related to site specific condition. Mega-herbivores and meso-herbivores dung abundance showed no significant relationship with Sporomiella concentrations. implying that neither group is the main contributors to Sporomiella concentration. There was also no significant difference in Sporomiella-concentration between the different areas of the park, providing no evidence that spores are differentially distributed throughout the park. Sporomiella concentrations showed no significant difference between the different types of vegetation and grasses within the park. This suggests that the spores are not specific to certain vegetation or grass types.