Dissertations / Theses on the topic 'Urban predator'

Giralang Pond was a water body, with little emergent or submerged vegetation, designed to trap fine sediment and buffer input of rising water to Ginninderra Wetland downstream. Ginninderra Wetland was designed to retain and use sediment nutrients and other potential hazardous materials in urban run-off. Water in the Wetland was more turbid and had lower magnesium concentration, redox potentials and dissolved oxygen concentration than did Giralang Pond. Water temperature was a minimum of 4 °C in the winter and reached a summer maximum of 30 °C Giralang Pond had more organisms but fewer taxa than Ginninderra Wetland. The greatest abundance in the pond resulted principally from high numbers of two numerically dominant species Calamoecia sp. and Micronecta sp.. More organisms were found in vegetated habitats of Ginninderra Wetland than open water habitats. The number of invertebrates and the number of taxa found in Typha domingensis did not differ significantly from similar estimates for Schoenplectus validus, Gambusia qffinis was the dominant predator in both water bodies. On one occasion, G. qffinis reached population densities of 35 individuals per m-2 . G. qffinis was five times more abundant in Gininnderra Wetland than in Giralang Pond and also showed a preference for vegetated areas. G. qffinis over-grazed it's prey on several occasions. G. qffinis, invertebrate predators and prey followed a pattern of a community in a stable predator-prey cycle. Prey in early spring increased population numbers and then decreased when G. qffinis and other predators increased their numbers. The pattern was further strengthened by occurring in both areas of open water and vegetated habitat types.

Surveys for adult sweetpotato whitefly parasites on ornamentals in urban areas and in cultivated cotton fields show high parasite activity in urban areas vs. activity in cultivated cotton fields. A previously unreported Drapetis spp. fly was identified and found to occur in cotton fields in several areas in the state.

Birds face many challenges from the process of urbanisation. Those species that are able to occupy urban areas offer opportunities to understand processes of acclimatisation to urban life and may help in the development of urban spaces for the benefit of wildlife. In many bird species, individuals that occupy territories in more urban areas show lower productivity and lower body condition of nestlings, which is thought to be mediated by food availability. Most of the studies exploring this issue were done on passerines and carried out in the global north, with very few studies exploring this topic on non-passerines, and even fewer in Africa. Studies addressing urban productivity in apex predators with slow life histories that are often of conservation concern are largely missing. Here, we explore the breeding performance of the African Crowned Eagles (Stephanoaetus coronatus) across an urbanisation gradient in KwaZuluNatal, South Africa. Specifically, we explored the hypothesis that living in an urban environment allows this species, which is typically a biennial breeder, to breed annually more often (i.e. increased breeding rate), and whether this might increase the productivity of this species. We also explore whether there may be any hidden costs of such a breeding strategy by examining the condition of chicks for pairs which had successfully bred in the previous year. We found that Crowned Eagles breeding in more urban areas attempted to breed more often (i.e., higher breeding rate), but that these birds also suffered from lower breeding success. These two contrasting responses counteracted each other and meant that overall productivity (number of young produced per occupied territory) was not influenced by urbanisation. Breeding annually did not appear to have a negative cost on the chick condition, as offspring in the year following a successful breeding attempt did not have lowered body condition. This species appears to be well adjusted to breeding in an urban environment. Crowned Eagles are currently considered vulnerable in South Africa, and ensuring that an urban population of this species is able to persist can help secure the conservation status of this charismatic species.

Domestic cats (Felis catus) are predators that can attain very high densities and have the potential to detrimentally affect prey populations. Densities of cats in the town of Reading were comparable with other UK studies, and were on average 463 cats/km", with cat density increasing as a function of housing density. Mean rates of predation were estimated at 18.3 prey items car I year' I, but this was highly spatially and temporarily variable. Predation by domestic cats may be removing up to 40% of the prey population in some species. Variation in rates of predation between individuals was high. Cat owners can influence the predatory habits of their cats by using belled collars and by restricting the access of their cats to the outdoors overnight. Male cats were found to have higher predation rates than female cats, especially when under 3 years of age. Within prey species, there was also variation in the likelihood of being predated. The roaming behaviour of male wood mice (Apodemus sylvaticus) leads to an increased likelihood of being predated, demonstrating a cost to the dispersing sex. The proportion of prey returned home by cats was investigated using faecal analysis. It was shown that as rates of predation are low in urban cats, faecal samples would need " to be collected over a longer period oftime to detect prey items. The average area ranged by a cat was 1.94ha and when occasional exploratory movements were included the ranging area increased to 6.88ha. Range area was not affected by sex or season, but ranges were found to be significantly larger at night than during the day. These data suggest that keeping cats in at night would reduce the distance that they range and reduce rates of predation. 9.

Thesis (M.S.)--University of Missouri-Columbia, 2007.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on November 1, 2007) Includes bibliographical references.

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2006.
Includes bibliographical references (p. 96-99).
The fate of New Orleans in the aftermath of Hurricane Katrina is uncertain. The rebuilding of the Gulf Coast presents the nation with the most massive redevelopment project in a single location ever. Reminiscent of the Urban Renewal changes between the late 1940s and early 1970s. Urban Renewal redevelopment projects were touted as being beneficial to the city by providing easier access to downtown and the construction of new housing. However, hindsight and scholarship coupled with the experience of thousands of residents, has taught us that the lasting effects of urban renewal included displacement of residents, disruption of community ties, and extensive psychological traumas associated with these shocks. In New Orleans, for example, the heart of the black business district along Claiborne Avenue in the Treme neighborhood, one of the oldest African American neighborhoods in the country, was cleared for the construction of the I-10 Expressway. The Storyville section, arguably the birthplace of jazz, was broken apart to make room for the Iberville Housing Projects. The fight against Armstrong Park continued for several decades, eventually ending in defeat with the displacement of over 400 families.
(cont.) Now, Hurricane Katrina has uprooted hundreds of low-income residents, many of whom were victims of Urban Renewal, others of whom are the children of those victims, raised on their stories. The neighborhood's history of cultural resistance is rooted in the public commons, once again under threat in the redevelopment process. New Orleans residents and organizers are scrambling for a foothold in the process despite widespread trauma and limited capacity. Planners have an opportunity to rethink their role in the context of synergistic damage accumulation, widespread trauma, and a new level of predatory planning. The time ripe to examine the lessons of the past and explore the implications they may have for the current rebuilding process in post-Katrina New Orleans.
by Kiara L. Nagel.
M.C.P.

Thesis: M.C.P., Massachusetts Institute of Technology, Department of Urban Studies and Planning, 2019
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 48-49).
With New York City in the throes of a severe affordable housing crisis, the City government and housing advocates have worked tirelessly towards the identification of landlords whose profit model is based on fraudulent deregulation of the rent-regulated housing stock. The problem is that these bad actors are not so easy to identify. With the refusal of the controlling agency, the New York State Department of Housing and Community Renewal (DHCR), to release data on units lost from the market, along the widespread use of limited liability companies (LLCs) to obscure ownership, it's difficult to both track changes in the market and to associate those changes with problematic actors.
The role of this thesis is to explore the creation of a methodology incorporating pre-existing work at the city and civilian level ("civic tech") to identify suspect patterns of behavior, recognizing that improved access to ownership data is key to identifying spatial and temporal patterns of change in the classification and pricing of rent-stabilized units. By leveraging tax data scraped by civic tech activists and cross-referencing it with property data, a relational database and associated SQL queries can make possible the identification of concentrated patterns of behavior occurring on properties by owners who have otherwise proven to be particularly adept at staying hidden. Look-up tables have been incorporated to create a method of analysis which is systematic and can be maintained and augmented as new information on ownership and management is accumulated over time.
This work is split into three parts: The first part of this work will begin with an initial exploration into the academic literature on rent-regulated housing, as well as the role of civic tech to supplement that literature. The second part of this work will outline the data integration methodology, using one census tract as a case study to test the feasibility of this approach. Finally, the work will explore ways in which this work could be implemented on a larger scale and the potential impacts of a successful execution of this methodology on legislation and prosecution targeting predatory landlords.
by Meagan Cherita Patrick.
M.C.P.
M.C.P. Massachusetts Institute of Technology, Department of Urban Studies and Planning

The ecology of mosquito populations in relation to weather conditions, emergent plants and predation in an urban wetland of Canberra was studied. Anopheles annulipes, Aedes notoscriptus, Aedes australicus, Aedes alboannulata, Culex annulirostris and Culex quinquefasciatus were found. Temperature was a major climatic factor in determining the abundance of mosquito populations in the wetland. First collections and subsequent development of mosquitoes in Ginninderra wetland are likely to depend on local weather conditions each year. The wetland proper was not a suitable habitat for mosquito breeding. Tall emergent vegetation may have obstructed oviposition and predation was also important in limiting colonization by mosquitoes. Instead, isolated temporary waterbodies which were free of predators, such as ground depressions, tyre tracks, domestic waste containers, were the most important habitats for mosquitoes adjacent to the Ginninderra wetland. Field experiments found that predation of mosquito larvae by mosquitofish Gambusia qffinis and notonectids Anisops was more efficient in sunlight than shade and this was affected by the height of emergent plants.

Thesis (MSc)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Invasive arthropod predators are one of the largest and most diverse groups of invasive insects in the world. Many are generalist predators, with cosmopolitan distributions due to their use as biological control agents in agriculture. Harmonia axyridis (Coleoptera: Coccinellidae), an invasive arthropod predator species native to Asia, which now has a world-wide distribution. It is considered one of the most successful biological control predator species and is generally considered to be economically beneficial. However, negative effects have recently emerged in agricultural and natural systems. Harmonia axyridis poses a threat to biodiversity as it outcompetes native species for food resources. It can also feed directly on native predatory arthropods that disrupt natural ecosystem processes. Their movement in-and-out of agricultural landscapes may depend on food availability with natural vegetation alongside agricultural areas often utilised for refuge and alternative food resources. This beetle has also been recorded in urban areas. The aim of this study was to determine how the invasive H. axyridis beetle uses the local landscape in the Western Cape province, South Africa, and to determine its threat to native species. I sampled urban landscapes, vineyards, natural vegetation/vineyard edge zones and pristine natural areas for arthropods every second month using a suction sampler. Data collected included the abundance and diversity of H. axyridis, herbivores, local predators and non-Harmonia ladybeetles. Most H. axyridis were collected in urban areas during all sampling periods. Highest abundance was recorded in May and July (winter). This indicates that urban areas were the preferred landscape feature and that these act as ovipositing areas, particularly as larval H. axyridis were also only collected in urban areas. Significantly, vineyards and natural vegetation had very low abundance of H. axyridis, questioning their value as a biological control agent in this region. Harmonia axyridis had a negative effect on the overall local arthropod community, as well as the predator and herbivore guilds, although it was positively correlated with the abundance of non-Harmonia ladybeetles. This suggests that H. axyridis and non-Harmonia ladybeetles are responding to the same resources in these landscapes. A negative correlation found between H. axyridis and the abundance of predators is most likely due to competition for the same resources (e.g. prey items). These negative impacts, along with their negligible value as biological control agents in agriculture, suggest that a programme should be implemented to control this invasive species. More specifically, control should be aimed in urban areas during winter when and where the species aggregates and when larvae are present.
AFRIKAANSE OPSOMMING: Geleedpotige roofdiere is een van die grootste en mees diverse groepe van uitheemse insekte in die wêreld. Die meeste is veelsydige roofdiere, met wêreldwye verspreiding te danke aan hul gebruik as biologiese beheer agente in landbou gebiede. Byvoorbeeld, Harmonia axyridis (Coleoptera: Coccinellidae), 'n indringer geleedpotige roofdier spesies inheems aan Asië, het nou 'n wêreldwye verspreiding. Dit word beskou as die mees suksesvolle roofdier spesies wat gebruik word vir biologiese beheer en word oor die algemeen beskou as ekonomies voordelig. Negatiewe effekte was onlangs aangeteken beide in landbou gebiede en natuurlike areas. Harmonia axyridis hou 'n bedreiging in vir inheemse biodiversiteit as dit inheemse spesies uitkompeteer vir voedsel bronne. Dit kan ook direk voed op plaaslike roofsugtige geleedpotiges wat trofiese vlakke ontwrig en uiteindelik, biodiversiteit. Hulle beweging in-en-uit landbou landskappe kan gekoppel word aan die beskikbaarheid van voedsel, en gebruik natuurlike plantegroei langs landbou gebiede dikwels as 'n toevlugs oord en area vir alternatiewe voedsel bronne. Harmonia axyridis word ook in stedelike gebiede aangeteken. Die doel van hierdie studie was om te bepaal hoe die indringer Harlekynkewer die plaaslike landskap gebruik met die fokus op wingerde in die Wes-Kaap provinsie van Suid-Afrika, en tweedens om die bedreiging wat hierdie kewer moontlik vir inheemse spesies te bepaal. Ek het arthropoda in stedelike landskappe, wingerde, natuurlike plantegroei / wingerd rand sones en ongerepte natuurlike areas elke twee maande met behulp van 'n D-vac versamel. Monsters was ontleed deur gebruik te maak van die getalle van H. axyridis, herbivore, plaaslike roofdiere en nie-Harmonia liewenheers kewers. Die meeste H. axyridis was in stedelike gebiede versamel gedurende al die seisoene, maar meeste individue was gedurende Mei en Julie (winter) versamel. Hierdie toon dat stedelike gebiede die voorkeur-landskappe is vir hierdie kewers en dat hierdie gebiede opgetree as eierleggende gebiede, veral omdat larwes van H. axyridis slegs in hierdie gebiede aangeteken was. Wingerde en die natuurlike plantegroei het baie lae getalle H. axyridis gehuisves wat hul waarde as biobeheermiddel bevraagteken. Harmonia axyridis het 'n negatiewe uitwerking op die algehele plaaslike geleedpotige gemeenskappe gehad, asook op die die roofdier en herbivoor gildes, maar hul getalle was positief gekorreleer met die getalle van nie-Harmonia liewenheerskewers. Dit dui daarop dat H. axyridis en nie-Harmonia liewenheerskewers beide reageer op dieselfde hulpbronne in hierdie landskappe. 'n Negatiewe korrelasie was gevind tussen die getalle van H. axyridis en die getalle van ander predatoriese geleedpotiges at waarskynlik te danke was aan mededinging tussen hierdie groepe vir dieselfde hulpbronne (bv prooi). Hierdie negatiewe invloede, asook hul verminderde waarde as biobeheeragente in die landbou, dui daarop dat 'n program in werking gestel moet word om hierdie indringerspesies te beheer. Meer spesifiek, beheer moet gedurende die winter en in stedelike gebiede geskied, waar en wanneer hierdie spesie op sy volopste is en waar larwes teenwoordig is.

Individual organisms often use cues from their natural environments to determine many behavioral and life-history “decisions.” These “decisions” are usually adaptive, i.e. a response to selection, because the environmental cues on which they are based reliably correlate with increased fitness over time. When the selected behavioral response to a natural cue no longer provides a fitness benefit, then selection for a new response may occur but individuals maintaining the previously selected response may suffer reduced survival and reproduction. Especially in human-modified landscapes individuals making a maladaptive behavioral or life-history choice based on those formerly reliable environmental cues may be faced with an “evolutionary trap”. In urban, or suburban, environments many factors have been altered in ways that could lead to evolutionary traps. Inappropriate behavioral responses by many individuals could lead to reduced demographic performance of urban populations relative to their wildland counterparts and to the decline of entire urban populations. In birds, maladaptive patterns of nest provisioning or vigilance may occur (a) when human-provided adult foods are easier to feed young because they are more abundant and predictable than foods appropriate for nestlings, or (b) when birds' perception of predation risk, which can be influenced by human disturbance, is greater than the real risk. By provisioning or attending their nests more or less than what is appropriate given the environmental level of resources and risks, the behavior of suburban parents may be contributing to high levels of nest failure during the nesting stage. To determine whether maladaptive parental care influences nest survival during the nestling stage, I conducted an experiment using Florida Scrub-Jays (Aphelocoma coerluscens). Suburban scrub-jays have lower nest survival during the nestling stage but higher survival during the incubation stage relative to wildland jays. Both predators and food abundance vary greatly between suburban and wildland scrub. The suburbs have a greater abundance of predators that may prey on both adult scrub-jays and their nests and more foods appropriate for adults but less nestling-appropriate food. This variation in risks and resources should affect the parental care behavior of suburban scrub-jays, which in turn may affect patterns of nest survival. In pre-treatment observations, I found that suburban females spent more time brooding than wildland birds but suburban males did not provision any more than wildland males. Experimentally increasing the perception of adult predation risk reduced parental care in both suburban and wildland females. Increasing the availability of nestling food reduced parental care in suburban females but had no effect in wildland females. Increasing food availability, but not predation risk, decreased call rates but increased call frequency in nestling scrub-jays from both habitats. However, neither parental care nor food availability had much influence on nest survival during the nestling stage. Instead, side nest concealment and the presence of helpers were the most important variables in nest survival analyses prompting other explanations besides maladaptive parental behavior or lack of nestling food resources for the habitat-specific difference in nest survival during the nestling stage.
ID: 031001430; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Adviser: David Jenkins.; Title from PDF title page (viewed June 24, 2013).; Thesis (M.S.)--University of Central Florida, 2012.; Includes bibliographical references (p. 49-58).
M.S.
Masters
Biology
Sciences
Biology

Os objetivos deste estudo foram quantificar a população de cães (Canis familiaris) e gatos (Felis catus) errantes em ambiente peri-urbano representado pelo Campus “Luiz de Queiroz” da Universidade de São Paulo, em Piracicaba, SP; descrever e comparar qualitativa e quantitativamente a dieta das duas espécies e estimar sua pressão de predação sobre as espécies silvestres de mamíferos. Durante os meses de julho de 2002 e janeiro de 2003, foram realizadas observações visuais e coletadas amostras de fezes de cães e gatos ao longo de uma transeção linear. Foram amostrados 0,276 km², ou 3,2% da área de 860ha do Campus. As características físicas de cada indivíduo (espécie, raça, pelagem, sexo, tamanho e marcas naturais) foram registradas para o cálculo da abundância das duas espécies na área amostrada, assim como o número de encontros por dia e por ambientes (rural e suburbano). A dieta foi analisada através das amostras de fezes que foram esterilizadas, lavadas, secas e triadas, sendo seus componentes identificados com o auxílio de referências bibliográficas. A importância de cada item foi expressa como porcentagem do número total de itens encontrados e como porcentagem de uma estimativa da biomassa consumida. A amplitude e sobreposição de nicho foram calculadas através dos índices de Levins e Pianka, respectivamente. O resultado da estimativa de abundância dos cães e gatos domésticos na área amostrada foi de 42 cães e 81 gatos. Cães e gatos são mais abundantes em ambiente suburbano que rural (T = 3,78, p < 0,001, N = 55; T = 8,38, p < 0,001, N = 55 respectivamente) e os gatos são mais abundantes que cães em ambiente suburbano (T = 6,76, p < 0,001, N = 55), porém não houve diferença significativa quanto à abundância de cães e gatos em ambiente rural (T = 0,82, p = 0,46, N = 55). Os resultados das análises das dietas indicam que os cães e gatos domésticos errantes são oportunistas de hábito generalista. Em 234 amostras de fezes foram detectadas 1212 ocorrências de 57 itens (68,4% de origem animal, 15,8% de origem vegetal e 15,8% formados por itens não alimentares). Considerando os itens de origem animal da dieta das duas espécies, invertebrados foram os mais consumidos, seguidos por mamíferos (cães: 57,05% e 25,15%; gatos: 63,24% e 20,51%, respectivamente). A amplitude de nicho (B) foi de 0,4463 para cães e 0,4892 para gatos. A sobreposição de nicho (O) foi próxima de completa (0,97108). O consumo de mamíferos por cães foi estimado entre 16,76 e 25,42 kg/ind/ano e por os gatos foi entre 2,01 e 2,9 kg/ind/ano, o que pode ser a causa das baixas densidades populacionais de pequenos mamíferos silvestres na área de estudo.
The goals of this study were to quantify the population of free-ranging dogs (Canis familiaris) and cats (Felis catus) in suburban areas; to describe and compare the diet of both species, and to estimate their predation pressure on the wildlife, at Campus " Luiz of Queiroz " of the University of São Paulo, in Piracicaba, SP. During the months of July 2002 and January 2003, visual observations and scats collection of dogs and cats were accomplished along a transect line. The sampled area comprised 0.276 km², or 3.2% of the 860ha of the Campus area. Physical characteristics of each individual (species, race, fur, sex, size and natural marks) were registered for the calculation of the abundance of both species in the sampled area, as well as the number of encounters a day and the environment (rural and suburban). The diet was analyzed through scats sterilized, washed, dried and sorted. Their components were identified with the aid of bibliographical references. The importance of each item was expressed as the percentage of the total number of items found and as the percentage of an estimate of the consumed biomass. Breadth and overlap niche were calculated through the indexes of Levins and Pianka, respectively. The results of estimate abundance of free-ranging dogs and cats in the sampled area were of 42 and 81 respectively. Dogs and cats are more abundant in suburban than rural environment (T = 3.78, p <0.001, N = 55; T = 8.38, p <0.001, N = 55 respectively) and the cats are more abundant than dogs in suburban environment (T = 6.76, p <0.001, N = 55), even though there was no significant difference between the abundance of dogs and cats in rural environment (T = 0.82, p = 0.46, N = 55). The results of diet analyses indicated that free-ranging dogs and cats are opportunistic predators of generalist habit. In 234 samples of scats 1212 occurrences of 57 items (68.4% of animal origin, 15.8% of vegetable origin and 15.8% formed by no food items) were detected. Considering the items of animal origin found in the diet of both species, invertebrates were the most consumed, followed by mammals (dogs: 57.05% and 25.15%; cats: 63.24% and 20.51%, respectively). Niche breadth (B) was 0.4463 for dogs and 0.4892 for cats. Niche overlap (O) was almost complete (0.97108). The consumption of mammals was estimated between 16.76 and 25.42 kg/ind/year for dogs and between 2.01 and 2.9 kg/ind/year for cats. This is a possible reason for the low population densities of small wild mammals in the study area.

I investigated if urban crows respond to con- and heterospecific alarm signals in predator and non-predator contexts in enclosures in the ZOO of Vienna. Crows responded strongly to the crow and also jackdaw alarms in both types of contexts, but also responded to the singing of great tit (control) in the predator context. This suggests that crows are aware of the danger the wolf and bear represent but are generally very cautious at the exotic Zoo animals.

Over 50% of the world’s human population resides in urban centres, and this is expected to increase as the global human population grows and people migrate from non-urban to urban centres. Concentrated in these urban areas are anthropogenic disturbances that impose additional challenges on wildlife compared to their non-urban counterparts. These challenges can be stress provoking. Through the release of corticosterone (CORT) reptiles can adapt to these stressors, physiologically and behaviourally, both in the short- and long-term. To investigate the relationships between stress activation and defensive tactics in wild urban Northwestern Gartersnakes (Thamnophis ordinoides) I conducted visual encounter surveys, along edge-focused transects, following a semi-constrained random sampling method. I sampled snakes at five sites, each with a different level of anthropogenic disturbance, in the Greater Victoria Area, BC. I sampled blood, observed anti-predator behaviour, and collected data on characteristics of snakes. The most disturbed site (with the most people, pets, and natural predators) also had the most snakes: those snakes also had highest H:L values (a proxy of CORT) in their blood compared to the other populations. Nevertheless, none of the snakes had H:L values that indicated chronic stress. Stress physiology was not correlated with anti-predator behaviour. More important to anti-predator behaviour was the size, sex/reproductive condition, and cloacal temperature of snakes. Although anthropogenic development can reduce habitat quality for some reptiles, Northwestern Gartersnakes coexist with recreationists at many sites in the District of Saanich. A multi-disciplinary approach is of paramount importance to understand the full effect of anthropogenic influences on wildlife.
Graduate
0433
0329

abstract: Human-induced rapid environmental change (HIREC) influences nearly all of Earth's ecosystems through processes such as urbanization. Previous studies have found that urbanization influences biodiversity patterns, often yielding an increase in the abundance of a few urban-adapted taxa at the expense of native species diversity. The western black widow spider, Latrodectus hesperus, is a medically-important pest species that often forms dense urban subpopulations (i.e., infestations) relative to the low-density subpopulations found throughout undisturbed, desert habitat. Here, I employ field and laboratory studies to examine the population ecology and stoichiometry of this urban pest to increase our understanding of the mechanisms underlying its success. The population ecology of ten black widow subpopulations spread across metropolitan Phoenix, AZ was examined during the peak breeding season (June-August). This study revealed that arthropod prey abundance, female mass and population density of females showed significant spatial variation across the ten subpopulations. Additionally, prey abundance and foraging success, measured as the number of carcasses found in webs, were a strong determinant of female mass and population density within each subpopulation. To test the mechanisms that drive black widow infestations, I used ecological stoichiometry to examine the nutrient (nitrogen and phosphorus) composition of spiders and arthropod prey from urban habitat, desert habitat and a laboratory diet regime. These studies revealed that (1) spiders are more nutrient rich than cricket prey in the field, (2) spider subpopulations exhibit significant spatial variation in their nitrogen composition, (3) nutrient composition of urban spider subpopulations does not differ significantly from Sonoran desert subpopulations, (4) laboratory-reared spiders fed a diet of only laboratory-reared crickets are more nitrogen and phosphorus limited than field-captured spiders, and (5) cannibalism by laboratory-reared spiders alleviated phosphorus limitation, but not nitrogen limitation, when compared to field-captured spiders. This work highlights the need to examine the population ecology of species relationships, such as predator-prey dynamics, to fully understand the fecundity and population growth of urban pest species. Moreover, the integration of population ecology and stoichiometry illustrates the need to address mechanisms like nutrient limitation that may explain why urban pest populations thrive and native species diversity suffers following HIREC.
Dissertation/Thesis
M.S. Biology 2012

This study focused on the interactions between small skinks and their major predators/competitors (birds) and prey (arthropods) in core and edge areas of small, long established remnant Cumberland Plain woodlands of Richmond, New South Wales, Australia. Eight study sites were selected (4 edge and 4 core) within the peri-urban environment to compare the abundance and diversity of small skinks, birds and arthropods. Of the three taxa, only arthropods maintained a similar abundance and diversity between edge and core areas. Birds and skinks were either in lower numbers in the perimeter areas (skinks), or were interior/perimeter specialists (birds). Arthropod diversity and abundance of preferred skink prey, was also examined. It was concluded that the distribution of arthropod prey was similar between core and edge areas, and therefore, was not considered to have an influence on small skinks’ ability to inhabit edges. However, large, aggressive/noisy birds (including skink and small bird predators) dominated edge areas. Those birds encountered in the edge foraged in a variety of niches, such as on the ground or they swooped from vantage points. This, coupled with other anti competitor behaviour (e.g. noise, aggression, flocking), placed these birds in proximity to skinks in the edge areas. However, as most of these birds were also predators of skinks, it was concluded that the evidence supported a predator/prey relationship in the perimeter area, rather than a competitive one. This was supported by predation rates on skinks, using decoys. Birds preyed on small skink in greater numbers in the perimeter of woodland remnants than in their interior. This predation pressure was sustained throughout the year. It was concluded that predation and/or displacement of skinks and small birds resulted in lower numbers being observed in edge compared to core areas. This study demonstrated that old, small remnants not continually exposed to major disturbances (e.g. logging, agricultural practices) can re-establish stability in terms of environmental conditions. However, a stable environment or a single taxonomic group does not necessarily predict the response individual taxa will have to edge habitats and that this can alter the interactions between dependent groups such as prey/predator or competitors. .
Doctor of Philosophy (PhD)

Partindo do paradoxo da insegurança - a ausência de correspondência na variação entre a taxa da criminalidade e o medo do crime - foram conduzidas duas etnografias em contextos caracterizados por realidades criminais distintas: na rua de Baixo, Porto, e na praça Nove, Rio de Janeiro. Com base na hipótese predatória, presumia-se que a insegurança urbana estaria situada no plano da (re)construção permanente do indivíduo com os espaços e os atores implicados no seu quotidiano. Foram analisadas dimensões do discurso (in)securitário - as representações dos lugares tidos como perigosos, a relação que se vai elaborando entre centralidades e espaços intersticiais, a construção de um imaginário povoado de figuras da ameaça, indicadores da relação entre dinâmicas de exclusão e insegurança, bem como as práticas de que as pessoas se servem para se protegerem do crime. Concluiu-se que o medo determina as rotinas daquelas vizinhanças, perturbando os seus laços, embora o risco tenda a ser depositado além das fronteiras que as redes de interconhecimento circunscrevem. Certos dispositivos - o respeito, a confiança, a familiaridade, o compromisso, a cooperação - revelam-se fundamentais na elaboração da multiplicidade de sentidos de que a (in)segurança se reveste, bem como daquilo que é definido como crime. A pesquisa permitiu distinguir entre falas globais do medo, que decorrem da participação em comunidades discursivas abrangentes, e falas locais do medo, dependentes das condições mais concretas da localidade. A combinação de ambas permite vislumbrar, primeiro, como o medo vai sendo dito e vivido localmente e, finalmente, como a imagem predatória da cidade pode abrigar em si dinâmicas tão contraditórias como aquelas que pendulam entre a confiança e a suspeição mútua.
An ethnographic research have been carried out in two distinct neighborhoods - rua de Baixo, in Porto, Portugal, and praça Nove, in Rio de Janeiro, Brazil; the purpose of which has been to reflect on the paradox of insecurity, the fact that there is a weak correspondence between the fear of crime and the actual incidence of crime. Based on the predatory hypothesis, it has been assumed that insecurity is situated in the permanent (re)construction of the individual's relations to the spaces traversed and actors encountered in their daily life. Certain dimensions contained within the discourse of (in)security have been analyzed, namely the representation of places seen as dangerous and the relationship between centers and interstitial spaces; the construction of an imaginary space filled with threatening figures; and the securitarian practices employed to organize daily life in a public space perceived as predatory. Although it was concluded that fear determines the daily routines of those neighborhoods, disturbing their internal bonds, the source of risk tends to be seen as originating beyond the bounds of the known and familiar. Certain characteristics, respect, confidence, familiarity, commitment, and cooperation, reveal themselves as fundamental to the elaboration of the multiplicity of meanings that are contained within (in)security. This research has made it possible to distinguish between different types of (in)security discourse, global "fear-talk" which takes place in discourse of broad overarching "communities," and local fear-talk which is dependent on more concrete conditions of the neighborhood. The combination of both gives insight into, firstly, how fear is spoken about and lived and, secondly, how the predatory image of the city can harbor within itself contradictory dynamics such as ones that range between mutual trust and mutual suspicion.

The lowlands of the Wet Tropics Bioregion (LWT) in north-eastern Queensland, Australia (situated between 18°37' S and 146°09' E, and 16°48'S and 145°41'E) is home to a broad range of threatened and/or endemic fauna species. Dingoes, Canis dingo, in the lowland Wet Tropics (LWT) are perceived to pose a threat to biodiversity conservation because of their predation on species listed as Vulnerable, Endangered, or Critically Endangered under the Nature Conservation Act 1992 (QLD) or Environment Protection and Biodiversity Conservation Act 1999 (Cth) (threatened fauna). These threats are likely to be greatest in periurban areas where dingoes may be subsidised by anthropogenic food resources, enabling them to reach relatively high population densities and thus exert significant predation pressure on threatened fauna. I investigated three main aspects to determine whether dingoes actually pose a threat to biodiversity conservation in the LWT, and whether public perceptions and attitudes match ecological reality: 1) dingo movement ecology; 2) dingo prey use; and 3) public perceptions and attitudes towards dingoes. My working hypothesis was that, although dingoes may be perceived to pose a threat to fauna populations in the LWT, their patterns of activity, land use and prey selection are more likely to lead them to prey on abundant, generalist mammals rather than on threatened fauna. I investigated dingo movement patterns in the LWT by GPS tracking nine dingoes to determine whether their temporal and spatial activity patterns suggested that they are likely to interact with threatened fauna, or whether an abundance of anthropogenic food subsidies increases the risk of spillover predation. I generated home ranges using five estimators, two of which have been used by past researchers to quantify dingo home ranges, and three which more-effectively capitalise on the high fix rates possible with modern GPS telemetry. I used two methods to determine the location of rest areas. Subsequent data were analysed using Compositional Analysis of habitat use, and Generalised Additive Models to establish the ways in which dingoes partition their diel activity patterns among human-modified and natural habitats. The results enabled me to make predictions about habitat use, potential prey types, relative prey use, modes of prey acquisition, and the ways in which foraging strategies might respond to changes in prey density. Mean home ranges were similar to those estimated by other studies for dingoes in eastern Australia, and suggest that dingoes in the LWT do not rely on anthropogenic food subsidies. Dingoes were active throughout the day and night but were most active during daylight. When dingoes were most active they were more likely to be in open, disturbed habitats than other habitat types, and when resting they were more likely to be in relatively-dry forests and woodlands, particularly wet sclerophyll. Rainforest was rarely used. It seems that dingoes rest in forested areas, possibly to avoid persecution by humans, and periodically move into open habitats (primarily sugarcane) to hunt. These observations match past suggestions that dingoes, as pursuit predators, are best suited to hunting in open habitats. I identified the diet of dingoes in the LWT and the potential threat posed to native fauna by using an established predation-risk assessment for threatened fauna, analysing scats and stomach contents, and generating Bayesian stable isotope mixing models using isotope values from the hair of dingoes and potential prey. The predation-risk assessment identified three ground-dwelling bird species that are likely to be threatened by dingo predation. An additional bird species, the estuarine crocodile, and six marine turtles were assessed separately, as their life history characteristics made them unsuitable for the risk assessment. These species may also be threatened by dingoes, and most are known to be susceptible to dingo and dog depredation. However, diet analysis did not identify any threatened species, and the primary prey of dingoes in the LWT was common, open-dwelling mammals. Separate Bayesian mixing models were generated using isotopic values from dingo hair, and four prey groups (agile wallabies; northern brown bandicoots & canefield rats; two melomys species; and green ringtail possums), and three habitat categories (primarily C3 vegetation – 'forest'; primarily C4 vegetation – 'open', and mixed C3 and C4 – 'mixed'). The models support the results of dietary analyses and identified that the most likely set of prey came from 'open' and 'mixed' habitats; 'forest' habitats were not an important source of prey. I gauged the knowledge and perceptions of WT residents toward the economic, social and ecological costs and benefits of dingoes, free-roaming domestic dogs and dingo × dog hybrids (wild dogs) in general, and their attitudes toward dingoes in particular, via a survey of WT households. A sub-component of this investigation focussed on costs and benefits to native fauna. An attitude typology was developed, and analysed using Principal Component Analysis and Generalised Linear Mixed Models. Descriptive statistics were generated from questions about wild-dog, dingo/human conflict, and public knowledge and perceptions of. Most WT residents believed that 'wild dogs' were a problem and were supportive of a number of methods of managing wild dogs There was strong support for a suite of potential management options for controlling free-roaming domestic dogs and limiting hybridisation, including desexing of domestic dogs in areas where there are wild dog problems, increased powers for council officers to penalise pet owners who allow their animals to roam unrestrained, and fitting pig dogs with tracking collars to allow relocation by their owners should they escape. Respondents perceived a range of costs of wild dogs but their primary concerns were predation livestock and threatened fauna, and disease transmission. However, almost one third of respondents believed that wild dogs provide social, economic, and/or environmental benefits, and the most-commonly cited benefit related to the dingo's role as a trophic regulator. Men and cattle farmers generally held the most negative attitudes toward dingoes; however, cattle farmers showed a strong desire to learn about them. I synthesised the results of my data chapters to determine whether dingoes actually pose a threat to threatened fauna and whether public perceptions and attitudes toward dingoes match ecological reality. My results suggest that dingoes in the LWT hunt abundant mammals in open habitats and are generally unlikely encounter threatened taxa. Thus, rather than posing a threat to native fauna populations, dingo predatory behaviour may represent an important ecological service. If dingoes do pose a threat to biodiversity conservation in the region it is likely to be in natural areas where remnant vegetation provides habitat for rare and threatened species; however, current dingo management practices tend to focus on areas where dingoes come into conflict with humans, primarily on agricultural holdings. However, some members of the public perceive that dingoes pose a threat to native fauna. The attitudes and beliefs of the public drive management decisions, and it is important that public perception of wildlife is informed by tangible evidence. Given the knowledge gaps in relation to the trophic effects of the dingo, and the potential implications of such knowledge gaps for biodiversity conservation, management decisions relating to dingoes in the LWT must be based on scientific evidence rather than anecdote. Management should focus on maintaining stable dingo packs in areas where they may be beneficial, unless shown to be otherwise, whilst concurrently aiming to quantify their impacts at targeted sites in natural habitats where they may not be.

Ph.D. Faculty of Humanities, University of the Witwatersrand, 2011
This study analyses the manner in which animals are represented in selected poetry from Malawi, Zimbabwe and South Africa. It discusses the various modes of animal representation the poets draw on, and the ideological influences on their manner of animal representation. It explores the kinds of poetic forms the poets employ in their representation of animals and examines the manner in which ecological or environmental issues are reflected in the poetry. Further, the study determines the extent to which the values expressed in the poems are consistent with, or different from, current ecological orthodoxies and the ways in which the metaphors generated in relation to animals influence the way we treat them. The study shows that in the selected poetry animals occupy a significant position in the poets’ exploration of social, psychological, political, and cultural issues. As symbols in, and subjects of, the poetry animals, in particular, and nature in general, function as tools for the poets’ conceptualisation and construction of a wide range of cultural, political, and philosophical ideas, including among others, issues of justice, identity, compassion, relational selfhood, heritage, and belonging to the cosmos. Hence, the animal figure in the poetry acts as a site for the convergence of a variety of concepts the poets mobilise to grapple with and understand relevant political, social, psychological and ecological ideas. The study advances the argument that studying animal representation in the selected poetry reveals a range of ecological sensibilities, as well as the limits of these, and opens a window through which to view and appreciate the poets’ conception, construction and handling of a variety of significant ideas about human to human relationships and human-animal/nature relationships. Further, the study argues that the poets’ social vision influences their animal representation and that their failures at times to fully see or address the connection between forms of abuse (nature and human) undercuts their liberationist quests in the poetry.

Ph.D. thesis is focused on the study of ecology and interactions among fungal disease horse chestnut leaf blotch, Guignardia aesculi, invasive pest horse chestnut leaf miner, Cameraria ohridella, and predatory mites of family Phytoseiidae. Ph.D. thesis consists of two main parts: 1) a detailed background research, and 2) six separate original published papers or manuscripts describing results of my own studies. The first study investigated spatial distribution of the first generation of C. ohridella in the urban environment in relation to the pest, the mortality of overwintering pupae at the end of vegetation season and the number of hatched C. ohridella and its parasitoids at the beginning of the following vegetation season. The second paper describes the interaction between C. ohridella and G. aesculi during vegetation season. The third and fourth papers deal with the effect of specific microctimatic conditions in site on the damage inflicted to horse chestnut leaves by G. aesculi. In addition, spatial distribution of G. aesculi in urban environment was studied. The fifth paper compared the species composition and the population density of Phytoseiidae between the Czech Republic and Greece. The sixth study described the species composition, abundance, population dynamics and sex ratio of phytoseiid mites inhabiting horse chestnut. The study also investigated, whether the abundance of predatory mites on horse chestnut leaves can be influenced by leaf damage caused by the horse chestnut leaf miner or G. aesculi during vegetation season.