There is a global effort to research the impacts of habitat fragmentation and degradation on wildlife. There is, however, still a need for greater understanding of ecological processes at work in fragmented and degraded habitat in peri-urban and agricultural areas. The study was undertaken in order to enable insights to be gained to provide a basis for management of fragmented habitat, using a single species as a focus. Eastern Bearded Dragon Pogona barbata is a reptile icon in Australia, but which is regarded anecdotally as being in decline, and for which little is known of the ecology. The aim of the study was to research the biology and spatial ecology of a species that had a dependent relationship on structural habitat of the nature of that found in peri-urban areas. Pogona barbata was selected as being an appropriate species in being terrestrial l /arboreal, having a territorial social structure, being an ecological generalist species, and being of a suitable size for study in relation to the size of fragmented habitat in western Sydney. Wild populations in relatively undisturbed habitat in the peri-urban area of western Sydney, Australia, were observed from 2000 to 2002, with additional data gained from museum collections and road-killed animals. Morphometrics were analysed by taking the ratio of a character to snout-vent length, and plotting that value against snout-vent length in order to more clearly see allometric change. Detailed tracking of animals using spool threads was used to collect data on microhabitat use, spatial activity and home range. The distribution of P. barbata across its range coincided with open forest and woodland habitat, which in some areas is subject to intensive urban and agricultural impacts. Pogona barbata is found to be insectivorous as a juvenile and omnivorous as an adult. As hatchlings grow, the relative length of the tail increases (positive allometry) until sexual maturity, and this coincides with an insectivorous diet. The onset of sexual maturity occurs just after the diet becomes omnivorous, and the relative tail length decreases (negative allometry) to a value that can be less than that of hatchlings. The gracile body form of juveniles is different from the robust body form of adults, and this is consistent with the difference in diet and microhabitat use. Factors affecting the persistence of the species were identified. Eggs were eaten by foxes on a regular basis, and hatchlings and juveniles were very rare, indicating an unbalanced demographic structure. The apparent rarity of hatchlings and juveniles may be due to crypsis. Road death was found to remove important breeding individuals from the population. An improved method of estimating testis volumes in lizards using three dimensions was used, which showed that the anatomy of P. barbata testes is bilaterally asymmetrical. It is currently assumed that reptile testes are at least bilaterally regular, but this is not the case in P. barbata. The outcome of this finding is that reproductive and other studies that rely on measurement of a single testis in two dimensions may miss significant data. Testis volumes for P. barbata in western Sydney in the past 20 years are highly abnormal, which coincides with increasing air pollution in the area. Extremes of testis condition were absent testes, very small testes, and extreme differences of testis size in individual animals. Resource partitioning was found, with microhabitat use, to be significantly different for juveniles, males and females. Juveniles and hatchlings used dense habitat with a high incidence of fine and coarse woody debris. The fine matter in the habitat upon which adult females also rely is lost in frequent fires that are used to control bushfire hazard. Pogona barbata is generally regarded as a sit-and-wait predator, on the basis of its being commonly observed on obvious perches. This study demonstrates that such perches are not the most important component of its habitat and that its foraging mode is that of a grazing omnivore. This study appears to be the first that addresses a seasonal shift in microhabitat use for a reptile in general terms. The pattern of daily activity changes with season, and changes in daily habitat preference based on age, sex and season, indicated that P. barbata required a diverse structural habitat. This habitat is affected by frequent hazard reduction fires. A new method of estimating animal home range is presented. The method consists of daily spool trace polygons collected by GPS and analysed in ArcView 3.2, with a spatial analysis output that indicates an estimated total home range and a confidence interval for that estimate. A typical result is an acceptable estimate within 20-30 sequential days of tracking an animal. That outcome is a considerable improvement on the currently accepted minimum of 50 independent days, being at least 100 calendar days. Pogona barbata ‘breaks the rules’ for a number of concepts in the biology of reptiles, and in this study has displayed some new insights in testis morphology, ontology and ecology. It was rare in the areas studied, lending support to the perception that the species is in decline. Reproductive suppression was suspected to affect the population in western Sydney. Pogona barbata has shown a range of characteristics that makes it useful as an umbrella species for the purpose of managing fragmented and degraded habitat in peri-urban and agricultural areas. A range of biological and ecological measures is required to enable effective habitat management of any species, and this study has provided some appropriate techniques for that purpose. / Doctor of Philosophy (PhD)

No description available.

This study determined the passage time and phage propagation time of salmonella specific phages, Felix O1 and S16, in 10 bearded dragons, based on re‐isolation from cloacal swabs and faecal samples following oral administration, as a possible tool for reducing salmonella shedding. In Study 1, Felix O1 was administered orally for 12 consecutive days. Over 60 days, swabs were taken from the oral cavity and cloaca and qualitative Salmonella detection as well as salmonella quantification from faecal samples were performed. In Study 2, a phage cocktail (Felix O1 and S16) was administered to half of the tested animals. Salmonella (S.) Eastbourne was also given orally to all animals. Oral and cloacal swabs were tested as in Study 1, and faecal samples were collected for phage quantification. Various Salmonella serovars were detectable at the beginning of the study. The numbers of serovars detected declined over the course of the study. S. Kisarawe was most commonly detected. Salmonella titres ranged from 102 to 107 cfu/g faeces. The phages (Felix O1 and S16) were detectable for up to 20 days after the last administration. The initial phage titres ranged from 103 to 107 pfu/ml. The study shows that the phages were able to replicate in the intestine, and were shed for a prolonged period and therefore could contribute to a reduction of Salmonella shedding.

<p>Genetic structuring is common in natural populations. It is important to identify and consider population structure when studying evolutionary processes. Recently, the discovery of genetic structuring in some lekking bird species has opened up new perspectives on our understanding of the evolution of lek mating systems.</p><p>This thesis uses molecular data to identify patterns of broad and fine scale genetic structuring in the lekking white-bearded manakin Manacus manacus. Additionally, data on male mating success, female visiting patterns and behavioural, morphological and territorial characteristics of individual males are used to identify variables that may influence the distribution of matings in this species.</p><p>Analysis of genetic divergence within the genus Manacus revealed genetic sub-structuring and limited gene flow between species/subspecies. There was no significant isolation by distance relationship. Factors such as physical barriers to gene flow may play a role in shaping the genetic structure of the bearded manakin genus.</p><p>White-bearded manakin leks on Trinidad were composed of groups of related males. More than one such kin group existed on each lek. That related males gather in groups suggests that genetic structuring is not simply a consequence of limited dispersal. Active choices must take place by both residential and newly arrived birds.</p><p>Female visits to, and matings with, males were non-random. Centrality of male display court was the only measured variable that consistently correlated with male mating success. More aggressive displays were made as the distance between courts decreased. There was no significant relationship between the number of aggressive displays made between males and relatedness levels. Males with high mating success spent more time in aggressive behaviours.</p><p>In conclusion, white-bearded manakin lek formation and display court acquisition is likely to be influenced by genetic relatedness levels and male-male interactions. Centrality of court seemed important in mating success and may be an indicator of male dominance. However, a variety of other factors may also influence mating success and may be variable over time.</p>

Genetic structuring is common in natural populations. It is important to identify and consider population structure when studying evolutionary processes. Recently, the discovery of genetic structuring in some lekking bird species has opened up new perspectives on our understanding of the evolution of lek mating systems. This thesis uses molecular data to identify patterns of broad and fine scale genetic structuring in the lekking white-bearded manakin Manacus manacus. Additionally, data on male mating success, female visiting patterns and behavioural, morphological and territorial characteristics of individual males are used to identify variables that may influence the distribution of matings in this species. Analysis of genetic divergence within the genus Manacus revealed genetic sub-structuring and limited gene flow between species/subspecies. There was no significant isolation by distance relationship. Factors such as physical barriers to gene flow may play a role in shaping the genetic structure of the bearded manakin genus. White-bearded manakin leks on Trinidad were composed of groups of related males. More than one such kin group existed on each lek. That related males gather in groups suggests that genetic structuring is not simply a consequence of limited dispersal. Active choices must take place by both residential and newly arrived birds. Female visits to, and matings with, males were non-random. Centrality of male display court was the only measured variable that consistently correlated with male mating success. More aggressive displays were made as the distance between courts decreased. There was no significant relationship between the number of aggressive displays made between males and relatedness levels. Males with high mating success spent more time in aggressive behaviours. In conclusion, white-bearded manakin lek formation and display court acquisition is likely to be influenced by genetic relatedness levels and male-male interactions. Centrality of court seemed important in mating success and may be an indicator of male dominance. However, a variety of other factors may also influence mating success and may be variable over time.

No description available.