Thesis (Ph.D)--Physics, Georgia Institute of Technology, 2009. / Committee Chair: Weiss, Howard; Committee Member: Cvitanovic , Predrag; Committee Member: Goldman, Daniel; Committee Member: Schatz, Michael; Committee Member: Wiesenfeld, Kurt. Part of the SMARTech Electronic Thesis and Dissertation Collection.

The goldfish (Carassius auratus) is a hardy exotic species that have established sporadically distributed feral populations throughout North America. In one shallow seasonally anoxic pond goldfish formed a large stunted population of 15-17,000 ind ha$ sp{-1}$, with 53% being small young of the year. Goldfish were predominantly benthic herbivores with little diet overlap with resident red-spotted newts (Notapthalmus v. viredescens). Thus in relatively simple systems lacking fish predators goldfish can be very successful. However in systems with a complex native fish community, goldfish have had less success in colonizing. This could be related to an inability of goldfish to cope with native predators. / Tests for assortative shoaling between brown and gold coloured morphs showed that gold coloured fish exhibited no colour based assortive shoaling, while brown fish showed slight but significant colour preferences for like-coloured fish. This level of shoaling preference did not improve after visual exposure or interaction with native predators, indicating that goldfish showed limited behaviourial responses to predators, and that they were unable to modify their response to a predation threat. Further trials allowing goldfish to interact with either pike (Esox lucius) or bass (Ambloplites rupestris), in both single species groups of predator-naive goldfish, and mixed species conditions of goldfish with predator-experience minnows, showed that goldfish did not alter their behaviour in the presence of minnows (Pimephales notatus) when the predators were not present. However, with the predators present goldfish altered their activities to a more minnow-like pattern and showed a significant improvement in anti-predator behaviour. This improved behaviour continued by goldfish when they were retested on their own, indicating that the goldfish were reacting to the predator and not the minnows. Goldfish colonization may therefore be limited not so much by predation or competition from native cyprinids, but more by the absence/presence of a suitable, native, predator-experienced fish from which to copy the appropriate anti-predator behaviours.

Northern Botswana's rural agricultural settlements bordering national parks and game reserves. In two study areas (Khumaga and Gweta, bordering Makgadikgadi Pans National Park), spatial, temporal and prey-type patterns of livestock predation were assessed. Cattle, goats, horses, donkeys and sheep were the key livestock types. Lion, leopard, cheetah, wild dog, black-backed jackal, spotted hyena and the Nile crocodile (occurring only in Khumaga) were the key predators. Oral interviews with farmers in these villages provided insights into the patterns and impacts of livestock predation on rural economies. Khumaga's livestock predation scenario is dominated by lion predation on cattle, goats and donkeys, leopard predation on small stock and calves, and crocodile on goats. Wet season predation rates were higher than dry seasons', except for spotted hyena, black-backed jackal and leopard. Leopard and black-backed jackal are dominant small stock predators in Gweta. lion are the main cattle and donkey predators (though at lower frequencies). Dry season predation rates are higher. Farmers who own more livestock appear to lose more Northern Botswana's rural agricultural settlements bordering national parks and game reserves. In two study areas (Khumaga and Gweta, bordering Makgadikgadi Pans National Park), spatial, temporal and prey-type patterns of livestock predation were assessed. Cattle, goats, horses, donkeys and sheep were the key livestock types. Lion, leopard, cheetah, wild dog, black-backed jackal, spotted hyena and the Nile crocodile (occurring only in Khumaga) were the key predators. Oral interviews with farmers in these villages provided insights into the patterns and impacts of livestock predation on rural economies. Khumaga's livestock predation scenario is dominated by lion predation on cattle, goats and donkeys, leopard predation on small stock and calves, and crocodile on goats. Wet season predation rates were higher than dry seasons', except for spotted hyena, black-backed jackal and leopard. Leopard and black-backed jackal are dominant small stock predators in Gweta. lion are the main cattle and donkey predators (though at lower frequencies). Dry season predation rates are higher. Farmers who own more livestock appear to lose more cattle than those who own few. Gweta contrasts with Khumaga, having livestock predation highest during dry seasons, less reduction in livestock sales and a lower value of pending compensation claims. These predation patterns synchronise with movements of zebra and wildebeest to and from the Boteti river. Losses of livestock affect the utility derived from livestock and monetary gains from direct sales. Costs due to loss of biodiversity, though not quantified, add to those borne by the State through predator control. Both the State and the farmers loose. These losses reduce the incentives of the latter to conserve species that contribute reduction in their returns. The issue of State expenditure on predator control illustrates the possible need for re-direction of such funds into farmer-based predator control, much as an integral part of the current southern African trend of community-based natural resource management. Key words: livestock predation, predator control, economics, conservation, Botswana. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1997.

As algae-derived biofuel is a promising renewable energy source, it is well-established that micro-algae have the potential to make a significant contribution to transportation fuel demand. Although it has many advantages including high areal productivity, there are many negative factors. One of these factors is the predation of algae by amoebas, protozoans, ciliates and rotifers, particularly in open pond systems. For example, the rotifer Brachionus plicatilis, is able to eat as much as 12,000 algae cells per hour and can be responsible for an entire pond crash within days. Thus, these higher organisms need to be controlled in order to satisfy large-scale algae crop and biofuel production demand. One method of predation control involves the introduction of a toxic chemical to an algal culture that the predator has a higher sensitivity to with respect to algae. Ideally, predation could be minimized or eliminated without a substantial effect on the algal culture growth. Chlorella kessleri was used as the algal culture and Brachionus calyciflorus as the source of predation. Research was conducted in five stages. First, chlorine dissipation tests were carried out using spring water, distilled water, Bolds Basal Medium (BBM), and three different dry weights of algal suspension in order to analyze the dissipation rate of the residual chlorine. The results showed that chlorine in distilled water and spring water rarely dissipated while chlorine concentration in algal suspension rapidly decreased by a maximum of 90% within the second hour. Second, acute chlorine toxicity tests were conducted in order to find the 24-hr LC50 of B. calyciflorus. The 24-hr LC50 of the test animal was 0.198 mg Cl/L. Third, chlorine toxicity tests were conducted in order to find the LC50 of Chlorella kessleri. The 24-hr LC50 of C. kessleri was 0.321 mg Cl/L. Based on these results, the test animal was more sensitive to chlorine than the test algae; therefore chlorine may be used to avoid algae pond crashes by B. calyciflorus. Fourth, C. kessleri and B. calyciflorus were combined into one test to determine how long it would take to observe an algal culture crash. The result demonstrated that the higher the population of predators in algal suspension, the faster it crashed. Finally, chlorine, C. kessleri, and B. calyciflorus were combined into one test to determine what chlorine concentration and dosing interval was needed to significantly reduce predation without significantly reducing algae growth. The results of the fifth experiment showed that the effective intermittent chlorine concentration was between 0.45 and 0.60 mg Cl/L, and a short interval of chlorine dosing was effective in inhibiting rotifers in algal suspension. Even though the rotifers in algal suspension were inhibited by 0.45 to 0.60 mg Cl/L, algae growth was greatly inhibited by chlorine. In this respect, future work is needed to reduce the effect on algae by chlorine or alternative chemicals.

The present research was conducted to assess the effect of Sparrowhawk predation on the tit population of Wytham Woods, Oxford. Chapter 1 describes the history of the Wytham hawk population until this study began and the nesting biology of the hawks during the study. Six to nine pairs of hawks settled in the wood each year, but reproductive success was low due to pesticide contamination. Chapter 2 shows that tit nesting success was reduced when they nested near hawk nests. Circumstantial evidence is presented for reduced tit nesting success throughout the wood since the return of the hawks. Chapter 3 examines rates of hawk predation during the nesting period. Findings indicate that hunting rates and the percentage of the diet formed by tits are regulated by prey availability or vulnerability, with highest predation rates occurring at the time that tits fledge. In Chapter 4 the selection of tits by hawks is analysed. Results indicate that on the basis of brood and physical characteristics adult tits were selected on the basis of availability and juvenile tits were selected primarily by date of fledging. The ratio of adult to juveniles taken differed between years and was thought to be related to the number of tits available per hawk each year. Chapter 5 presents estimates showing that 22-42% of each segment of the tit population was killed by hawks each year. The effects of these losses are discussed, concentrating on the shift in the structure of the tit breeding population which has occurred since the hawks returned to the wood. In Chapter 6 the findings of the study are compared to the findings of previous predator-prey research and the attributes of Wytham as an area for studying predation discussed.

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / Brassica vegetables and oilseeds are economically important crops worldwide. These crops are associated with several destructive and widespread insect pests. In Australia these pests include six species, Plutella xylostella (Linnaeus), Pieris rapae (Linnaeus), Hellula hydralis Guenée, Helicoverpa punctigera (Wallengren), Brevicoryne brassicae (Linnaeus) and Myzus persicae (Sulzer), which are the focus of this research. Among them P. xylostella (diamondback moth or DBM) is the most serious and destructive insect pest. Little is known about the potential of predators, which may be able to contribute to control diamondback moth, although some field studies have shown the overall importance of predators in controlling this key pest. The aim of this study was to develop a method that allows study of predator-prey trophic interactions in the field. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1294814 / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2007

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / Brassica vegetables and oilseeds are economically important crops worldwide. These crops are associated with several destructive and widespread insect pests. In Australia these pests include six species, Plutella xylostella (Linnaeus), Pieris rapae (Linnaeus), Hellula hydralis Guenée, Helicoverpa punctigera (Wallengren), Brevicoryne brassicae (Linnaeus) and Myzus persicae (Sulzer), which are the focus of this research. Among them P. xylostella (diamondback moth or DBM) is the most serious and destructive insect pest. Little is known about the potential of predators, which may be able to contribute to control diamondback moth, although some field studies have shown the overall importance of predators in controlling this key pest. The aim of this study was to develop a method that allows study of predator-prey trophic interactions in the field. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1294814 / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2007

Thesis (M.E.S.)--The Evergreen State College, 2007. / Title from title screen (viewed 1/24/2008). "MES thesis." Includes bibliographical references (p. 79-88).

Thesis (Ph.D.)--University of Wollongong, 2005. / Typescript. Includes bibliographical references.

Thesis (M.S.)--Humboldt State University, 2008. / Includes bibliographical references (leaves 58-66). Also available via Humboldt Digital Scholar.