Effects of oxazepam concerning on social behavior in guppies are still unknown. The purpose ofthis thesis is to investigate if the benzodiazepine oxazepam has effects on fish behavior in terms ofsocial preferences and responses to predation risk using an olfactory cue mixture. After anexposure period of 15 days to 100 μg/l of oxazepam, behavioral experiments were performed overtwo days. Results indicate that oxazepam exposed fish were more social at the beginning of theexperiment, which differ from what was expected and from previous social preferences studies.Moreover, less social behavior was found as a result of combining oxazepam treatment andolfactory cue mixture (predator cues and guppy skin extract) treatment.

Doctor of Philosophy(PhD) / The European red fox (Vulpes vulpes L.) is a well known predator of native species and domestic stock, and is recognised as one of Australia’s most devastating vertebrate pests. Current fox management relies heavily on poisoning using baits impregnated with sodium monofluoroacetate (1080). This reliance on 1080 is likely to continue given the lack of viable alternatives for controlling foxes, so that, in the meanwhile, it is important to improve the efficiency of the current techniques. Factors affecting the susceptibility of individual foxes to bait include their ability to locate it, as well as the bait’s palatability and toxicity. The economic costs associated with using different bait types, the pattern and density of their distribution will also affect the efficiency of control programs. It is essential to examine and refine all such issues to ensure efficient use of the 1080 baiting technique. This thesis focuses generally on problems associated with management of the fox in eastern Australia. More specifically, I investigate the factors affecting the efficiency of fox baiting practices on the central tablelands of New South Wales. The study was conducted largely on agricultural lands near the town of Molong (33010’ 37”S, 148087’15”E) on the central tablelands of New South Wales. This area was chosen as it is broadly representative, in terms of land use, of a large region of eastern Australia. The highly modified, predominantly agricultural landscapes near Molong are well suited to foxes, and conflict with the predominantly pastoral community means that fox management is widely undertaken. I determined the persistence of 1080 in two commonly used bait types, Foxoff® and chicken wingettes, under different climatic and rainfall conditions. The rate of 1080 degradation did not change significantly between the central tablelands and the relatively hotter and drier western slopes. Foxoff® baits remained lethal for longer than wingettes under all conditions, although their rate of degradation generally increased with increasing rainfall. I confirmed the presence of defluorinating micro-organisms in thesoils of eastern Australia for the first time, and suggest that, following removal from the bait, 1080 would not persist in the environment for long. Bait should be attractive and highly palatable to ensure that the target species will find and consume it upon discovery. Caching, where discovered food is removed but not immediately consumed, may potentially reduce the efficacy and cost-effectiveness of baiting campaigns. I quantified the caching of chicken wingette, day-old chick and Foxoff® baits by inserting transmitters into bait material and assessing whether it was eaten or cached following removal. The intensity of caching did not change significantly between seasons. Type of bait had the largest influence on caching intensity, with a greater percentage of non-toxic Foxoff® baits (66.9%) being cached than either wingettes (5.7%) or day-old chicks (4.5%). The percentage of toxic (1080) baits cached was even greater, suggesting that 1080 bait may be less palatable, and detectable to foxes. I also investigated the use of conditioned taste aversion to reduce multiple bait uptake by foxes. Levamisole, an illness-inducing chemical, was added to bait and the fate of removed bait was again monitored via radio-telemetry. Following consumption of a levamisole-treated bait, foxes avoided eating treated baits but consumed untreated baits. I concluded that a reduction in bait consumption was achieved through learned aversion to levamisole rather than via conditioned taste aversion to baits. Adding levamisole to baits, especially non-toxic bait such as rabies vaccines, could potentially be used to reduce bait monopolisation by individual foxes. Fox density and den site preferences were assessed by investigating the distribution and density of fox natal dens on one property (9.6 km2) over three consecutive years. A total of 9 natal dens were located in 2000 and 2001, declining to 6 in 2002. No preference was shown for den sites on the basis of habitat, slope or aspect, but more dens were located under, or adjacent to cover. Assuming that each natal den represents a breeding pair and that the population sex ratio did not differ from parity (1:1), the site contained a prebreeding density of 1.9 foxes/km2 in 2000 and 2001, and 1.25 foxes/km2 in 2002. Given that the mean number of cubs is 4.0, the post-breeding density was estimated at 5.6 and 3.75 foxes/km2 in 2000/2001 and 2002, respectively. The results demonstrated that high densities of foxes occur on agricultural lands. The success and likely accuracy of the technique to monitor fox density suggests that it may be used to calibrate more efficient abundance estimates that will be essential for the strategic management of foxes in future. Pest animal management strategies are traditionally assessed for their effectiveness, with less consideration being given to the efficiency or cost of achieving the desired effect. I used cost-effectiveness analyses to compare between different baiting strategies based on the longevity, palatability and handling/replacement costs associated with each bait type. The results indicated that, when measured on a total cost-per-bait-consumed basis, wingettes and day-old chicks were the most cost-effective baits for campaigns of up to 4 weeks duration. This demonstrates the importance of including the longevity, and particularly the palatability of bait, when assessing cost-effectiveness. However, it is recognised that other factors, including the consistency of dosage and uptake by nontarget species, may be equally or more important in deciding the appropriate baiting strategy. The spatial and temporal application of fox baiting in the region overseen by the Molong Rural Lands Protection Board was examined between January 1998 and December 2002 as a case study to evaluate the apparent effectiveness of cooperative management practices. Most landholders (78.8%) did not bait for foxes during this period. Based on known dispersal distances, the effect of fox immigration into baited areas was determined. The results indicated that no areas baited for foxes were separated by a sufficient buffer distance (>9.58 km) from unbaited areas to be protected from fox immigration. This suggests that, at current levels of coordination, the effectiveness of most baiting operations in eastern Australia is compromised over the long term by fox immigration. However, it is recognised that short-term reductions in fox density may sometimes be all that are required to reduce predation to acceptable levels, especially for seasonally-susceptible prey. Ultimately, the cost-effectiveness of control should be evaluated in terms of the response of the prey rather than that of the predator. This study has highlighted deficiencies in current ‘best-practice’ baiting techniques. Specific recommendations for current baiting practices, in addition to future research, are also given. In brief, these include minimising free-feed baiting, increasing the minimum distance between bait stations, and, where possible, presenting the most palatable bait. Continued research into conditioned taste aversion, aerial baiting, and techniques to reduce caching are recommended as potential techniques to improve the efficiency of baiting practices.

Turbidity has generally been viewed as having detrimental effects on fish; yet, many turbid habitats in the world are also abundant with fish. This phenomenon is often explained as fish enjoying reduced predation pressure in turbid habitats. This represents a trade-off situation where fish should select clear or turbid habitats that provide maximum net benefits. Because turbidity reduces light penetration, both predator and prey visual ranges are reduced, rendering both less efficient foragers. For this reason, I suspected that the benefits of a turbid environment would be greatest in the presence of predators and hypothesized that when predation risk is high, prey should prefer turbid water. Laboratory experiments showed that regardless of predation risk, fathead minnows (Pimephales promelas) preferred feeding in a turbid habitat. The presence of a predator, yellow perch (Perca flavescens) or black bullhead (Ameiurus melas), caused minnows to reduce feeding. There was on interaction between water clarity and predation risk, water clarity and predation risk, thus, appeared to affect the minnows’ habitat selection independently. The predator’s effect on the prey was the same whether in turbid or clear water. Using the prey distributions established in the lab experiment, key parameters and assumptions were identified for a computer model which simulated both prey and predator responses to turbid water and their interactions. The model predicted that prey would always prefer the turbid habitat when one was available. Predators generally used both clear and turbid habitats. Only when its foraging efficiency was reduced significantly did the predator show strong avoidance of turbid water. As the number of predators increased, predators used both clear and turbid habitat more evenly. Turbid environments seem to provide important habitats for small and juvenile fish. It may benefit small fish by reducing predator efficiency or reduce prey energy expenditure. / October 2006

Turbidity has generally been viewed as having detrimental effects on fish; yet, many turbid habitats in the world are also abundant with fish. This phenomenon is often explained as fish enjoying reduced predation pressure in turbid habitats. This represents a trade-off situation where fish should select clear or turbid habitats that provide maximum net benefits. Because turbidity reduces light penetration, both predator and prey visual ranges are reduced, rendering both less efficient foragers. For this reason, I suspected that the benefits of a turbid environment would be greatest in the presence of predators and hypothesized that when predation risk is high, prey should prefer turbid water. Laboratory experiments showed that regardless of predation risk, fathead minnows (Pimephales promelas) preferred feeding in a turbid habitat. The presence of a predator, yellow perch (Perca flavescens) or black bullhead (Ameiurus melas), caused minnows to reduce feeding. There was on interaction between water clarity and predation risk, water clarity and predation risk, thus, appeared to affect the minnows’ habitat selection independently. The predator’s effect on the prey was the same whether in turbid or clear water. Using the prey distributions established in the lab experiment, key parameters and assumptions were identified for a computer model which simulated both prey and predator responses to turbid water and their interactions. The model predicted that prey would always prefer the turbid habitat when one was available. Predators generally used both clear and turbid habitats. Only when its foraging efficiency was reduced significantly did the predator show strong avoidance of turbid water. As the number of predators increased, predators used both clear and turbid habitat more evenly. Turbid environments seem to provide important habitats for small and juvenile fish. It may benefit small fish by reducing predator efficiency or reduce prey energy expenditure.

Turbidity has generally been viewed as having detrimental effects on fish; yet, many turbid habitats in the world are also abundant with fish. This phenomenon is often explained as fish enjoying reduced predation pressure in turbid habitats. This represents a trade-off situation where fish should select clear or turbid habitats that provide maximum net benefits. Because turbidity reduces light penetration, both predator and prey visual ranges are reduced, rendering both less efficient foragers. For this reason, I suspected that the benefits of a turbid environment would be greatest in the presence of predators and hypothesized that when predation risk is high, prey should prefer turbid water. Laboratory experiments showed that regardless of predation risk, fathead minnows (Pimephales promelas) preferred feeding in a turbid habitat. The presence of a predator, yellow perch (Perca flavescens) or black bullhead (Ameiurus melas), caused minnows to reduce feeding. There was on interaction between water clarity and predation risk, water clarity and predation risk, thus, appeared to affect the minnows’ habitat selection independently. The predator’s effect on the prey was the same whether in turbid or clear water. Using the prey distributions established in the lab experiment, key parameters and assumptions were identified for a computer model which simulated both prey and predator responses to turbid water and their interactions. The model predicted that prey would always prefer the turbid habitat when one was available. Predators generally used both clear and turbid habitats. Only when its foraging efficiency was reduced significantly did the predator show strong avoidance of turbid water. As the number of predators increased, predators used both clear and turbid habitat more evenly. Turbid environments seem to provide important habitats for small and juvenile fish. It may benefit small fish by reducing predator efficiency or reduce prey energy expenditure.

Doctor of Philosophy(PhD) / The European red fox (Vulpes vulpes L.) is a well known predator of native species and domestic stock, and is recognised as one of Australia’s most devastating vertebrate pests. Current fox management relies heavily on poisoning using baits impregnated with sodium monofluoroacetate (1080). This reliance on 1080 is likely to continue given the lack of viable alternatives for controlling foxes, so that, in the meanwhile, it is important to improve the efficiency of the current techniques. Factors affecting the susceptibility of individual foxes to bait include their ability to locate it, as well as the bait’s palatability and toxicity. The economic costs associated with using different bait types, the pattern and density of their distribution will also affect the efficiency of control programs. It is essential to examine and refine all such issues to ensure efficient use of the 1080 baiting technique. This thesis focuses generally on problems associated with management of the fox in eastern Australia. More specifically, I investigate the factors affecting the efficiency of fox baiting practices on the central tablelands of New South Wales. The study was conducted largely on agricultural lands near the town of Molong (33010’ 37”S, 148087’15”E) on the central tablelands of New South Wales. This area was chosen as it is broadly representative, in terms of land use, of a large region of eastern Australia. The highly modified, predominantly agricultural landscapes near Molong are well suited to foxes, and conflict with the predominantly pastoral community means that fox management is widely undertaken. I determined the persistence of 1080 in two commonly used bait types, Foxoff® and chicken wingettes, under different climatic and rainfall conditions. The rate of 1080 degradation did not change significantly between the central tablelands and the relatively hotter and drier western slopes. Foxoff® baits remained lethal for longer than wingettes under all conditions, although their rate of degradation generally increased with increasing rainfall. I confirmed the presence of defluorinating micro-organisms in thesoils of eastern Australia for the first time, and suggest that, following removal from the bait, 1080 would not persist in the environment for long. Bait should be attractive and highly palatable to ensure that the target species will find and consume it upon discovery. Caching, where discovered food is removed but not immediately consumed, may potentially reduce the efficacy and cost-effectiveness of baiting campaigns. I quantified the caching of chicken wingette, day-old chick and Foxoff® baits by inserting transmitters into bait material and assessing whether it was eaten or cached following removal. The intensity of caching did not change significantly between seasons. Type of bait had the largest influence on caching intensity, with a greater percentage of non-toxic Foxoff® baits (66.9%) being cached than either wingettes (5.7%) or day-old chicks (4.5%). The percentage of toxic (1080) baits cached was even greater, suggesting that 1080 bait may be less palatable, and detectable to foxes. I also investigated the use of conditioned taste aversion to reduce multiple bait uptake by foxes. Levamisole, an illness-inducing chemical, was added to bait and the fate of removed bait was again monitored via radio-telemetry. Following consumption of a levamisole-treated bait, foxes avoided eating treated baits but consumed untreated baits. I concluded that a reduction in bait consumption was achieved through learned aversion to levamisole rather than via conditioned taste aversion to baits. Adding levamisole to baits, especially non-toxic bait such as rabies vaccines, could potentially be used to reduce bait monopolisation by individual foxes. Fox density and den site preferences were assessed by investigating the distribution and density of fox natal dens on one property (9.6 km2) over three consecutive years. A total of 9 natal dens were located in 2000 and 2001, declining to 6 in 2002. No preference was shown for den sites on the basis of habitat, slope or aspect, but more dens were located under, or adjacent to cover. Assuming that each natal den represents a breeding pair and that the population sex ratio did not differ from parity (1:1), the site contained a prebreeding density of 1.9 foxes/km2 in 2000 and 2001, and 1.25 foxes/km2 in 2002. Given that the mean number of cubs is 4.0, the post-breeding density was estimated at 5.6 and 3.75 foxes/km2 in 2000/2001 and 2002, respectively. The results demonstrated that high densities of foxes occur on agricultural lands. The success and likely accuracy of the technique to monitor fox density suggests that it may be used to calibrate more efficient abundance estimates that will be essential for the strategic management of foxes in future. Pest animal management strategies are traditionally assessed for their effectiveness, with less consideration being given to the efficiency or cost of achieving the desired effect. I used cost-effectiveness analyses to compare between different baiting strategies based on the longevity, palatability and handling/replacement costs associated with each bait type. The results indicated that, when measured on a total cost-per-bait-consumed basis, wingettes and day-old chicks were the most cost-effective baits for campaigns of up to 4 weeks duration. This demonstrates the importance of including the longevity, and particularly the palatability of bait, when assessing cost-effectiveness. However, it is recognised that other factors, including the consistency of dosage and uptake by nontarget species, may be equally or more important in deciding the appropriate baiting strategy. The spatial and temporal application of fox baiting in the region overseen by the Molong Rural Lands Protection Board was examined between January 1998 and December 2002 as a case study to evaluate the apparent effectiveness of cooperative management practices. Most landholders (78.8%) did not bait for foxes during this period. Based on known dispersal distances, the effect of fox immigration into baited areas was determined. The results indicated that no areas baited for foxes were separated by a sufficient buffer distance (>9.58 km) from unbaited areas to be protected from fox immigration. This suggests that, at current levels of coordination, the effectiveness of most baiting operations in eastern Australia is compromised over the long term by fox immigration. However, it is recognised that short-term reductions in fox density may sometimes be all that are required to reduce predation to acceptable levels, especially for seasonally-susceptible prey. Ultimately, the cost-effectiveness of control should be evaluated in terms of the response of the prey rather than that of the predator. This study has highlighted deficiencies in current ‘best-practice’ baiting techniques. Specific recommendations for current baiting practices, in addition to future research, are also given. In brief, these include minimising free-feed baiting, increasing the minimum distance between bait stations, and, where possible, presenting the most palatable bait. Continued research into conditioned taste aversion, aerial baiting, and techniques to reduce caching are recommended as potential techniques to improve the efficiency of baiting practices.

The mechanism of predator categorization has not been understood well yet. I examined how coloration pattern and predator size influence categorization by a prey under laboratory conditions. I tested the reaction of great tit (Parus major) to the plush dummies of sparrowhawk (Accipiter nisus), coloured as sparrowhawk, pigeon, robin and great tit. The same color variations were made in the sizes of a sparrowhawk and great tit. My results indicate that the coloration plays the main role in the recognition. The size is not important in the dummies coloured as the predator and the conspecific but it plays a role in recognition of other tested dummies (coloured as the pigeon and robin).

The purpose of this study was to investigate whether there is regional variation in the abundance and habitat use of tiger sharks (Galeocerdo cuvier) within in a model seagrass ecosystem. Abundance was determined with catch rates on drumlines and habitat preferences were investigated using acoustic tracking of large tiger sharks (n=4). I found spatiotemporal variation in the probability of catching at least one shark and in catch rates on days sharks were caught. In general, sharks were present throughout more of the year and in higher abundances in the northern region. Habitat use also varied between regions. In the northern region, sharks moved randomly with respect to habitat, while in the southern region sharks preferred shallow habitats. Although preliminary, these results suggest that large predator abundance and habitat use may vary over relatively small spatial scales and that such variation may be useful for elucidating their ecological role.

In this paper I will offer an overview the evolution of civil liberties in the United States. These liberties, I argue, were meant to protect individuals from unwarranted exercises of power from the government, but ultimately were not intended to hamper the government’s ability to carry out basic government functions, such as self defense. Next, I examine the parallel evolution of the ability of the executive to exercise broad ranging powers in pursuit of foreign policy, especially in regard to self defense. After that I argue that the current policy not necessarily represent the administration choosing self defense over an individual’s civil liberties. Rather, it represents the notion that at a fundamental level, a state will always choose to pursue foreign policies designed to protect itself, and that even the domestic legal institutions that have evolved in the United States recognize that fact. / text

Predator harassment is an anti-predator behaviour that may increase a harasser’s risk of predation but decrease the potential for predation for other members of a group. The Cape ground squirrel (Xerus inauris) is a facultative cooperative breeder from southern Africa that harasses venomous snakes. The objective of my study was to examine predator harassment to determine: 1) whether predator harassment was part of alloparental care by comparing harassment behaviour among age and sex classes; 2) how individuals adjusted their behaviour against different snake species; 3) whether olfaction was used in discrimination of snakes; and 4) if individuals possessed venom resistance against venomous snakes. I found that females with juvenile offspring harass snakes longer and more intensely than other individuals, suggesting that predator harassment was a maternal behaviour. Squirrels increased harassment, inspection and vigilant behaviours with risk when exposed to both live snakes and snake odours suggesting they can use olfaction to discriminate snake predators. I also found no venom resistance in Cape ground squirrels concluding the cost of envenomation was significant.