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Patterns and pathways of lead contamination in mottled ducks (Anas fulvigula) and their habitatKearns, Brian Vance January 1900 (has links)
Doctor of Philosophy / Department of Biology / David A. Haukos / Mottled ducks (Anas fulvigula) are dabbling waterfowl species native to coastal wetlands of the Gulf of Mexico of the United States and Mexico. Although closely related to common waterfowl species such as the mallard (A. platyrhynchos) and American black duck (A. rubripes), the mottled duck exhibits unique behavior, mainly in its life history as a non-migratory species. As such, because of population declines caused by predation, habitat destruction, and environmental contaminants, this species requires specialized conservation concerns and species-specific management to protect population numbers. The goal of this study was to assess ongoing effect of observed lead (Pb) contamination and exposure issues in mottled ducks and their habitats, which I achieved by conducting assessments that will provide managers habitat and organism level metrics to detect and mitigate lead in mottled ducks and their environments.
My field study was conducted at the Texas Chenier Plain National Wildlife Refuge Complex (TCPC), which was the area of greatest mottled duck density on the Texas Coast. I first created a body condition index to provide managers a tool to monitor population health, and a proxy for lead exposure and avian health without destructively sampling individuals. I then used presence-only maximum entropy (MaxENT) and multivariate statistical modeling procedures in conjunction with mottled duck movement data to elucidate sets of habitat conditions that were conducive to predicting the occurrence of mottled ducks and environmental lead “hot spots”. MaxENT analyses suggested that lead in the top portion of the soil column is similarly related to all environmental variables considered, may be increasingly available after large-scale environmental disturbances. Lack of variation in coarse-scale habitat use between breeding and non-breeding seasons may further point to a food-based exposure pathway for lead as mottled ducks switch from an invertebrate to plant diet, either as a result of changing age classes or normal adult phenology, during the period of increased lead exposure. Using stable isotope ratio analysis, I then tested environmental samples of soil and vegetation as well as mottled duck blood to determine isotopic signatures that were consistent with particular sources of lead deposition (e.g., lead shot pellets, leaded fossil fuel combustion, industrial effluents). Comparisons suggested a great deal of similarity to lead shot reference values in vegetation and blood samples, especially in blood samples with higher concentrations of lead present. Last, I conducted a formal Ecological Risk Assessment (ERA) procedure to quantify the risk to mottled ducks from lead exposure in their current habitat and direct managers towards effective mitigation and habitat management strategies to reduce exposure in the future. One scenario suggested that mottled ducks were at greatest risk from eating an invertebrate-based diet, but lead content values at the TCPC suggest that a plant-based diet may provide a higher lead exposure risk for mottled ducks, depending on true levels of bioavailability in environmental media.
Overall, I determined that mottled ducks experience greatest lead exposure risk from lead shot pellets on the TCPC or in nearby habitat, while potentially also experiencing low levels of exposure from several other sources. Additionally, management efforts that focus on plants that do not provide food resources for mottled ducks as a potential environmental sink for lead contamination, such as phytoremediation, may prove effective in reducing the overall lead load from historical activities that likely deposited much of the lead in this ecosystem.
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Lesser prairie-chicken movement, space use, survival, and response to anthropogenic structures in Kansas and ColoradoPlumb, Reid Thomas January 1900 (has links)
Master of Science / Biology / David A. Haukos / The lesser prairie-chicken (Tympanuchus pallidicinctus) is an endemic North American prairie grouse once widely distributed in the southwestern Great Plains. Recent population declines and continued threats to lesser prairie-chicken populations prompted the U.S. Fish and Wildlife Service to list the species as “threatened” under the protection of the Endangered Species Act of 1973 in May 2014. The northern extent of the species range in Kansas and Colorado supports 2/3 of the remaining range-wide population of lesser prairie-chickens, but has thus far been relatively understudied. Concern for species viability has created a need to fill current knowledge gaps in lesser prairie-chicken ecology, provide more recent demographic information, and develop appropriate conservation actions. I evaluated female survival, movement, space use, and effects of anthropogenic features during the breeding seasons of 2013 and 2014. I captured and radio-tagged 201 females with satellite GPS (N = 114) and VHF (N = 82) transmitters within the three ecoregions of Kansas and Colorado. Mean daily movement varied by region, year, and breeding season period but the amount of space used was consistent between ecoregions and years. On average, females moved 1352 m ± 12 [SE] per day. Females moved the greatest distances during the lekking period of the breeding season with females moving 2074 m ± 36 per day. Females were most sedentary during the brooding period moving only 780 m ± 14 per day. Mean breeding season home range size was estimated to be 340 ha ± 27. The lekking period had the greatest amount of movement as a result of females visiting leks to find mates, copulate, and search for nest locations. Female’s movements were reduced during the brooding period because of physical limitations of the brood mobility. Variation in movement between ecoregions was most likely a product of fragmentation as females moved 10-30% more in northwest Kansas compared to the study sites, which was characterized by northwest Kansas having the greatest degree of fragmentation. Survival varied by ecoregion with females in northwest Kansas having the lowest probability of surviving the 6-month breeding season compared to other ecoregions. Estimated 6-month breeding season survival during 2013 and 2014 was 0.455 (95% CI = 0.38 – 0.53). Survival was lowest during the nesting period, which claimed 59.5% of all observed mortalities. Survival increased from 2013 to 2014 in northwest Kansas as grassland habitats recovered from extreme drought conditions in 2013. Drought was less severe in south-central Kansas and survival rates remained fairly consistent across years. Avian and mammalian predators caused 45.7% and 34.3% of breeding season mortalities, respectively. Other mortalities were either cause by snakes or were unknown (5.7%, 14.3%). Overhead cover may have been limited from drought conditions causing nesting females to be more visible to avian predators during incubation. When pooled across years and ecoregions, rump-mounted GPS transmitters did not adversely affect female survival when compared to commonly used necklace style VHF transmitter (VHF: 0.48 95% CI = 0.39 – 0.58; GPS: 0.50 95% CI = 0.38 – 0.64). Distance to distribution power lines and lek were significant predictors of female space use within their home range with females behaviorally avoiding distribution power lines and using space closer to leks. Space use decreased with increasing oil well density. Females avoided areas that had well densities of 23 wells/250 ha. Observed female locations were further from anthropogenic features but closer to leks on average than at random. Avoidance behavior of anthropogenic features may result in functional habitat loss and reduce the amount of suitable habitat available; compounding previously fragmented landscapes. Anthropogenic features may limit movement by acting as barriers on the landscape and potentially disrupt population connectivity. Furthermore, habitats selected for nesting and brooding may result in potential ecological traps because of reduce breeding success when impacted by increased occurrence and densities of anthropogenic features. Reduced breeding success can have significant negative impacts on population persistence. Average home range size across all ecoregions indicated that female lesser prairie-chickens need at least 340 ha of habitat to fulfill her life-history requirements during the breeding season. Brooding habitats need to be in close proximity (≤ 750 m) to nesting cover to reduce distance traversed by newly hatched broods. Reducing grazing pressure will ensure that sufficient vertical habitat structure is available during the nesting period and increase female survival; especially in times of drought. Mangers should restrict construction of anthropogenic features near or within suitable lesser prairie-chicken habitat with emphasis on distribution power lines. Well densities should not exceed 1 well/60 acres (11 wells/section) for a >10% probability of use. However, because the affect that density of wells has on demographic rates of lesser prairie-chickens has yet to be determined, a conservative approach where well densities in or adjacent to grassland patches should be minimized as much as possible is best.
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Stalking the hunting debate : trophy hunting, integrity and ideologyBadenhorst, Charl F. 12 1900 (has links)
Thesis (MA (Philosophy))--University of Stellenbosch, 2003. / Trophy hunting remains a highly contentious issue within environmental spheres
of debate. Whether it is morally justifiable for humans to kill other living creatures
for recreation, even if by doing so generates revenue in aid of their conservation,
is a contested issue that will not easily rest and on which there is as yet no clear
ground for consensus between opposing viewpoints. Within environmental
philosophy, the topic of the morality of sport hunting has been extensively
discussed, with the focus shifting constantly between various moral and ethical
theories; while in an African context, big game trophy hunting continues to be a
vital source of income for wildlife conservation and rural communities amidst the
contested meaning of its role and place. The phrase "the hunting debate" refers
to the ongoing discourses that surround the contested meaning and morality of
recreational hunting, while the groups involved in the debate are polarised along
the lines of preservationist and conservationist viewpoints.
The lack of consensual ground between opposing viewpoints and the strength of
the conviction of held beliefs and values result in a stalemate. In this thesis an
attempt is made to map this stalemate by identifying the role players relevant to
an African context, and the groups who stand in opposition to one another,
namely those within the anti-hunting and pro-hunting communities. Points of
contention are highlighted, and the various moral theories inherent in the debate
are identified, with the crux of the stalemate being shown to be essentially
between deontological moral assumptions regarding the wrongness of hunting,
and utilitarian approaches that attempt to justify it morally according to an
aggregation of benefits. The meaning of hunting for the Ethical Hunter is also
clarified, as is the meaning of the hunting experience as a philosophical and
historical symbolic construction.
The political nature of the debate is also explored against the backdrop of a
postmodern description of culture and communities, as is the way in which
certain symbols are employed as ideological tools within the debate, and how
they serve to influence public opinion regarding the morality of hunting. The
hunting experience is discussed in detail as a historical construct, and certain
hunting narratives are briefly identified in this regard, as are the symbolisms of
indigenous hunter-gatherer hunting practices. This is in order to identify
similarities or differences in meaning of the hunting experience, and so doing
reach a position to say what hunting with integrity may mean.
Integrity as a Virtue is promoted as the founding conceptual criterion around
which discussions of trophy hunting may be based, and trophy hunting of the Big
Five species in Africa is contextually explored with this notion in mind. While
trophy hunting of the Big Five offers tangible and much needed instrumental
benefits, it does not stand up well to a critique of "the hunting experience" as a
historical construct and as a commodified package, as The Hunting Experience in
this sense is seen to lack authenticity in terms of an idealised and primitivist
notion of the meaning of Ethical Hunting. The paradox of Big Five trophy hunting
is that it is very hard to justify, as it is seen to reinforce dualistic assumptions of
nature, and objectify animals as a commodity; notwithstanding the moral
uncertainty surrounding the act it can, however, be seen to offer benefits that are
pragmatic and tangible, for ecosystems as well as humans. However, with the
exception of strictly utilitarian approaches, the findings of this thesis suggest that
instrumental economic benefits are not enough to justify trophy hunting of the Big
Five in Africa from a moral philosophical perspective, although in keeping with the
aims of the study no attempt is made to posit one moral position over another as
to the morality of trophy hunting.
In conclusion, it is suggested that trophy hunting be de-emphasised as an
inevitable and singularly viable wildlife management tool, and instead be
understood in terms of a short-term strategic compromise, as doing so allows
more room for the growth of ideas that may offer an acceptable alternative.
Based upon the findings of this study, it is acknowledged that such a compromise
is essentially and theoretically also a compromise of integrity, which may
nevertheless within certain contexts be necessary in the short-term.
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Spatio-temporal patterns of infectious disease vectors in the eastern Smoky Hills, KansasGanser, Claudia January 1900 (has links)
Master of Science / Department of Biology / Samantha M. Wisely / Nearly 30% of emerging infectious diseases are caused by vector-borne pathogens with wildlife origins, posing a risk for public health, livestock, and wildlife species of conservation concern. Understanding the spatial patterns of exposure to dipteran vectors and their associated pathogens is critical for epidemiological research to target prevention and control of vector-borne infectious diseases. In recent years, Western Equine encephalitis, St. Louis encephalitis, West Nile Virus encephalitis and avian malaria have not only been a public health concern but also a conservation concern, specifically the conservation of grassland nesting birds. Although the central Great Plains is the most specious region for grassland nesting birds, their role in the enzootic (primary) amplification cycle of infectious diseases may lead to further population depressions, and could potentially result in spill-over events to humans and livestock. The goals of my thesis were 1) to identify the underlying causes of spatio-temporal abundance patterns of mosquito vectors within the grasslands of the eastern Smoky Hills, and 2) to create probabilistic distributions of functional disease vectors, to evaluate disease risk in Greater Prairie-chicken (Tympanuchus cupido, surrogate species for other grassland nesting birds). First, I found that temporal dynamics in mosquito abundances were explained by maximum and minimum temperature indices. Spatial dynamics in mosquito abundances were best explained by environmental variables, such as curvature, TWI (Topographic Wetness Index), distance to woodland and distance to road. Second, the overall predictive power of the ecological niche models of important vector species in the grasslands of the Smoky Hills was better than random predictions, indicating that the most important predictor variables in their distribution were: distance to water, TWI, AASHTO (soil particle size distribution), and mean temperature during the coldest quarter. Furthermore, the spatial analysis indicated that Greater Prairie-chicken nest in areas with a higher probability of vector occurrence than other potentially available habitats within the grasslands. However, I failed to detect a significant difference in the probability of vector occurrence at nest of infected versus uninfected females. Understanding the distribution and abundance patterns of vectors of infectious diseases can provide important insights for wildlife conservation as well as public health management.
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Apparent survival, dispersal, and abundance of black-tailed prairie dogsGoldberg, Amanda R. January 1900 (has links)
Master of Science / Department of Biology / Jack F. Cully, Jr. / Black-tailed prairie dogs (Cynomys ludovicianus) are a species of management and conservation concern. Prairie dogs have lost both habitat and occupied area due to plague, which is caused by the bacterium Yersinia pestis, pest control, and habitat conversion to agricultural land. Our goals were to estimate survival rates and dispersal rates, and to compare methods for
estimating abundance of black-tailed prairie dogs for both management and conservation. We
trapped black-tailed prairie dogs at four small National Parks from April 2009 through August
2011. Prairie dogs were trapped and marked for two trapping sessions per year in order to
estimate seasonal rates of apparent survival. Apparent survival rates were estimated using the
package RMark in R to construct models for program MARK. We found estimates to vary
according to field site, sex, year, and season (summer or winter). Possible reasons for the
differences in survivorship among sites could be presence of disease, quality of forage,
predation, or frequency of dispersal. Visual counts were also conducted each trapping session
beginning in April of 2010 to estimate abundance. Mark-recapture, mark-resight, and visual counts were compared to determine which method would be the most effective for estimating
abundance of prairie dogs. We found mark-resight to produce the most precise estimates of
abundance. While it costs more money to conduct a mark-resight estimate than visual counts
because of repeated sessions, they produced significantly different results from one another 75% of the time, which was especially apparent on sites that had some form of visual barriers such as tall vegetation and uneven ground. However, if further information is needed in terms of sex
ratios, age ratios, or the exact number of prairie dogs, then mark-recapture is the only method that can be used. Land managers need to address the level of accuracy needed, topography, and vegetation height before choosing which sampling method is best for the prairie dog towns in question. Finally, we looked at rates of intercolony and intracolony dispersal by placing 149 VHF collars and 6 GPS collars on prairie dogs at three colonies. Intracolony dispersal was also monitored through visual observation and trapping records over the three years of the study. We found 23 intracolony and eight intercolony dispersal events. Combined, these three studies offer insight not only into monitoring of prairie dog populations but also potential influence by plague both within and among colonies of prairie dogs.
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Conservation history, hunting policies and practices in the South Western Mozambique borderland in the 20th centuryJose, Paulo Lopes January 2017 (has links)
A thesis submitted to the Faculty of Humanities of the University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Doctor of Philosophy in History, August 2017 / This study uses both primary and secondary sources to investigate the history of the communities living in the southern Mozambique hinterland in the 20th century. It specifically examines the evolution of the colonial hunting laws and the establishment of hunting reserves in southern Mozambique. In this thesis, I argue that the Portuguese colonial administration put little effort into the protection of fauna and ecosystems in the south western Mozambique hinterland. Portuguese hunting laws were issued to provide the colonial system with revenue – through a system of fees imposed on licensed hunters when entering Mozambican forests and hunting reserves – rather than to improve fauna management. Colonial laws (particularly fees for the hunting permits) made it difficult for the majority of local African peasants to access game resources, on which during periods of drought and lack of foodstuffs they depended for subsistence. The study explores the extent to which postcolonial development projects affected conservation and the livelihoods of communities living in conservation areas. It shows how the period following independence was also characterised by mass killing of wildlife. In 1978, as part of the construction of the Massingir dam, Frelimo government officials relocated families living along the Elephants valley to areas having poor soils in Coutada 16, thus reducing the ability of the cultivators to produce enough food to sustain their families. Lack of food supplies increased the dependence of local families on bush meat for food. The armed conflict, which broke out immediately after independence in 1975 and lasted until 1992, contributed to the mass killing of wildlife, as both government soldiers and RENAMO fighters exploited bush for food. The end of the armed conflict allowed the Government of Mozambique (GoM) to implement projects aimed at rehabilitating the ecosystems destroyed by war and the transformation of Coutada 16 into the Limpopo National Park (LNP) in 2001. In 2002, the integration of the LNP into the Great Limpopo Transfrontier Park (GLTP) turned into reality Hertzog´s 1927 desire to create a transnational conservation area across the South Africa – Mozambique border. / XL2018
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Rhinonomics: a biodiversity center in the cradle of human kind in support of a legalised rhino horn tradeMcCormack, Duane Allan 07 October 2014 (has links)
A fading legacy
Through the intensive investigation of the rhino trade, the thesis proposes the development of a biodiversity center to serve as a research, education, training and enforcement facility which will support a legalized rhino horn trade. The relationship between architecture and nature. In so doing, it questions whether architecture can effectively facilitate the conservation of our spectacular wildlife through and ecological approach to brief, site and context. The thesis promotes and architecture that is respectful of its natural surroundings. An architecture that provides occupants with facilities that are conducive to the conservation of endangered species.
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The role of air and waterborne odors in orientation and food detection in three species of marine turtlesUnknown Date (has links)
The cues used by marine turtles to locate foraging areas in the open ocean are largely
unknown though some species (especially the green turtle [Chelonia mydas], the
loggerhead [Caretta caretta], and the leatherback [Dermochelys coriacea]) somehow
locate areas of high productivity. Loggerheads can detect airborne odors, but a capacity
to orient has not yet been investigated. In this comparative study, tethered loggerheads
and leatherbacks were exposed to dimethyl sulfide (DMS) or food odors in a laminar
flow of air. Turtles did not orient into the air current. Free-swimming loggerheads and
green turtles were also exposed to air- or waterborne food (squid) odor plus a neutral
visual stimulus. Both species showed increases in swimming activity and biting behavior
to both stimuli. These results suggest that airborne odors are likely not used to locate
distant areas, but that they are used in localized food searching efforts. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection
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Growth rates and body condition of juvenile green turtles (Chelonia mydas) in Dry Tortugas National Park and Marine Protected AreaUnknown Date (has links)
Dry Tortugas National Park (DRTO) consists of 261.8 km2 in the Gulf of Mexico and provides protection to marine species facing a multitude of threats. Among the many species that utilize DRTO is the green sea turtle (Chelonia mydas). I examined seven years of capture-recapture data to determine how the body condition (using Fulton’s equation, K = M/L3) and growth rate for juvenile green turtles vary within, and among size classes in DRTO, and how those rates compare to similar populations in other locations. Body conditions ranged from 0.77 to 1.71 (mean 1.3 SD ± 0.16). Growth rates ranged from 2.5 to 9.9cm/yr (mean 5.5 cm/yr SD ± 1.25), which is a high growth rate for green turtles. Establishing growth rates and body condition for a specific population can provide insight into life history and health of that population, as well as important data
for comparison to populations in other areas. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015 / FAU Electronic Theses and Dissertations Collection
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Wading bird prey production and prey selection in a dynamic wetlandUnknown Date (has links)
Anthropogenic impacts, such as habitat destruction and spread of exotic species,
are contributing to the sixth major extinction event in Earth’s history. To develop
effective management and conservation plans, it is important to understand the ecological
drivers of at-risk populations, assess the ability of a population to adapt to environmental
change, and develop research methods for long-term ecosystem monitoring. I used
wading birds nesting in the Florida Everglades, USA as a model system to address the
challenges of managing and monitoring populations within an ecosystem greatly
impacted by anthropogenic activities. Specifically, my project investigated 1) the prey
selection of wading bird species, and the role of prey and foraging habitat availability on
annual nesting numbers, 2) the ability of using diet change to predict species adaptability
to a rapidly changing environment, and 3) the use of sensory data to provide low-cost,
long-term monitoring of dynamic wetlands. I found that tricolored herons, snowy egrets, and little blue herons consumed marsh fish larger than those generally available across
the landscape. Additionally, number of nests initiated by tricolored herons, snowy egrets,
and little blue herons was strongly correlated with the annual densities of large fish
available within the Everglades landscape. Conversely, number of nests initiated by
wood storks, great egrets, and white ibises was more correlated with the amount of
foraging habitat availability across the nesting season. Wood stork diets changed
considerably since the 1960’s, consisting of mainly sunfish and exotic fish as opposed to
marsh fishes dominant in historical diet studies. Storks also consumed more exotic fish
species than they did historically. This diet plasticity and the species’ ability to exploit
anthropogenic habitats may be conducive to maintaining population viability as storks
experience widespread human-induced changes to their habitat. Sensory-only data
models generated complementary results to models that used site-specific field data.
Additionally, sensory-only models were able to detect different responses between size
classes of fish to the processes that increase their concentrations in drying pools.
However, the degree to which sensory variables were able to fit species data was
dependent upon the ability of sensors to measure species-specific population drivers and
the scale at which sensors can measure environmental change. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection
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