In south Florida, the Greater Everglades ecosystem supports sixteen species of wading birds. Wading birds serve as important indicator species because they are highly mobile, demonstrate flexible habitat selection, and respond quickly to changes in habitat quality. Models that establish habitat relationships from distribution patterns of wading birds can be used to predict changes in habitat quality that may result from restoration and climate change. I developed spatio-temporal species distribution models for the Great Egret, White Ibis, and Wood Stork over a decadal gradient of environmental conditions to identify factors that link habitat availability to habitat use (i.e., habitat selection), habitat use to species abundance, and species abundance (over multiple scales) to nesting effort and success. Hydrological variables (depth, recession rate, days since drydown, reversal, and hydroperiod) over multiple temporal scales and with existing links to wading bird responses were used as proxies for landscape processes that influence prey availability (i.e., resources). In temporal foraging conditions (TFC) models, species demonstrated conditional preferences for resources based on resource levels at differing temporal scales. Wading bird abundance was highest when prey production from optimal periods of wetland inundation was concentrated in shallow depths. Similar responses were observed in spatial foraging conditions (SFC) models predicting spatial occurrence over time, accounting for spatial autocorrelation. The TFC index represents conditions within suitable depths that change daily and reflects patch quality, whereas the SFC index spatially represents suitability of all cells and reflects daily landscape patch abundance. I linked these indices to responses at the nest initiation and nest provisioning breeding phases from 1993-2013. The timing of increases and overall magnitude of resource pulses predicted by the TFC in March and April were strongly linked to breeding responses by all species. Great Egret nesting effort and success were higher with increases in conspecific attraction (i.e., clustering). Wood Stork nesting effort was closely related to timing of concurrently high levels of patch quality (regional scale) and abundance (400-m scale), indicating the importance of a multi-scaled approach. The models helped identify positive and negative changes to multi-annual resource pulses from hydrological restoration and climate change scenarios, respectively. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Neste trabalho foi feito um diagnóstico da situação do Parque Nacional das Emas(GO)onde se procurou evidenciar as razões pelas quais o parque não corresponde de forma eficaz aos objetivos de conservação e uso público. Foram trabalhadas questões como o uso do solo no entorno, os recursos humanos e financeiros disponíveis, a estrutura de funcionamento das instituições competentes e o zoneamento interno do parque, buscando-se sempre alternativas de manejo. A abordagem da área de estudo foi feita através da identificação de Unidades de Paisagem de diferentes grandezas (UPs). Essas UPs permitiram o enquadramento do Parque em contextos maiores, favorecendo, ao mesmo tempo, a compreensão de sua dinâmica interna. Como recurso metodológico, as UPs possibilitaram a integração de questões do âmbito natural com o político-administrativo.

MSc., Faculty of Science, University of the Witwatersrand, 2011 / Abundance counts of ungulate species which are carried out using an aerial census are susceptible to measurement errors. These measurement errors result from environmental factors such as vegetation cover and the resultant effect that factors, such as the annual rainfall pattern, have on the accuracy of the count. Given these measurement errors, models of population abundance that are based on these counts should not only account for the population dynamic process - they need to model the measurement error process simultaneously in order to produce plausible estimates. In addition to this, the recorded counts from these censuses do not give a breakdown of the total count into the different gender and life-history stages of the animals counted. This research report investigates the usefulness of a hierarchical Bayesian hidden process modelling approach at explicitly including the measurement error process and a sub-model for the gender and life-history stage of the animals counted into a population dynamics model based on the aerial census counts. The data used are aerial counts of Kudu in the Kruger National Park from 1983 to 1993. The result is a model which estimates the measurement error in each year of the census and also breaks down the overall count into the numbers in each gender and life-history stage. The usefulness of the model is evaluated based on statistical model diagnostics.

This research represents the first multi-year investigation of the feeding ecology of Gombe’s Cercopithecus populations. The main goal of this study was to identify dietary overlap and distinctiveness among the phenotypes in our study group, a mixed species group of guenons comprised of C. ascanius, C. mitis, and C. ascanius x C. mitis hybrids. Field assistants collected feeding data using ad libitum observations as well as instantaneous scan sampling at 30-minute intervals from July 2014 to December 2018. A total of 63 plant species were identified in our group’s diet. Results indicate that a significant difference exists between the diets of each phenotype. The results also found an unusually high percentage of invertebrate eating (54%) in our group. These findings suggest that invertebrates are an important food resource for the Gombe study group and may help facilitate coexistence in an environment where there are many sympatric primate species. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

The objective of this study was to quantitatively document interactions between black bears and backcountry visitors, and to identify the factors affecting those encounters. Fine hundred and ninety-two interactions were observed. The most common responses of visitors to bears were to watch, walk toward, and talk to others and/or point at the bear. Bears responded to humans largely by walking away, watching, traveling around, walking toward, and running away from people. Each behavior for both species was categorized into one of four response classes: (1) fear/avoidance, (2) neutrality, (3) approach, or (4) aggression. Over 65 percent of visitor responses were neutral. People were least likely to react to bears with fear/avoidance behavior. Bears also were most likely to be neutral. Of particular interest is the low occurrence of aggression shown by bears. Less than two percent of all responses fell into this category, most of which were exhibited by two animals. We witnessed no interactions which resulted in injury or even contact between visitors and bears. When ursid aggression did occur, bears appeared to be more aggressive in June, with younger visitors, and at close distances. Both human aggression and fear were correlated with short interactions. Bear behavior was greatly altered by possession of camper foods. Bears were more neutral and walked toward people less after they had begun to eat. They also showed much less fear of visitors at this time. Other correlations of both human and ursid behavior with biotic and abiotic variables ( temporal, spatial, environmental, etc.) are presented and discussed. Recommendations for improved management are also suggested.

Numerous supraglacial and proglacial lakes have developed on debris-covered glaciers in conjunction with 20th-century retreat associated with global warming. When a glacier holds a substantial debris cover on its lower reach and/or is calving into a proglacial water body, the behaviour of its terminus can be modified to varying degrees compared to that of land-terminating or debris-free glaciers. The terminus is not just retreating from its frontal position but it is disintegrating through several processes that are linked. An improved understanding of these glacier margins is needed for the prediction and management of hazards associated with these types of lakes for hydroelectric power generation, recreational purposes and areas threatened by potential glacier outburst floods as well as for the interpretation of glacio-geological records and reconstruction of former glacial environments and palaeoclimate. The principal research question of this study is how processes of ice loss contribute to the terminus disintegration of a debris-covered, lake-calving glacier. This is addressed by an application of a field-based strategy which includes extensive field observations of variables, processes and their controls, and subsequent analysis of the data in the light of previous models and concepts. The study attempts to combine and integrate different aspects of glaciological research that have previously been examined mostly separately. It investigates the prevalent processes at the glacier terminus and their controls over different time periods ranging from days to years at Mueller, Hooker and Tasman Glaciers in Mount Cook National Park, New Zealand. The data form the basis for models of calving and pond development and future retreat scenarios. This study has demonstrated that this glacial environment is characterised by ice-frontal processes with complex inter-relationships that vary between glaciers and in particular between stages of terminus development. While surface ice melt in the terminus area is substantially reduced by supraglacial debris, sub-debris melt contributes the largest fraction of ice loss. Other important effects of debris are restraining thermal undercutting, reducing subaqueous melt and decreasing buoyancy. Data from supraglacial ponds and proglacial lakes show that limnological factors become increasingly important with increasing pond/lake size. Changes in water currents and temperature lead to changes in significance and rates of ice loss processes, the most important being the change from melting to predominantly calving. This study has confirmed the hypothesis that thermal undercutting is the rate-controlling process for calving. This process is controlled by the cliff geometry, debris supply, subaqueous geometry and water temperatures, currents and level variations. The results from the examination of calving processes suggest that the process of regular, progressive calving through the stages suggested previously may not be widely applicable to slow-moving, lake-calving glaciers. The several forms of subaerial calving identified in this study can present themselves as largely independent events, a combination of events or as a progression. At the central submerged part of the ice face, subaqueous ice melt is likely to be the dominant form of ice loss, leading to horizontal ice loss. Subaqueous calving is prevalent in gently-sloping lateral areas, leading to vertical ice loss. This process is controlled by buoyancy forces which are affected by sedimentation and lake and glacier geometry. The onset of subaqueous calving in the earlier stages of lake development is a crucial process for the transition to faster disintegration and ice loss, accelerating subaqueous melt. Due to the complex inter-relationships attempts to formulate general relationships between calving or retreat rates and other glaciological parameters may not be feasible.

(1) Aerial survey methods for estimating population size of feral water buffalo in northern Australia were examined. (2) Line transect models underestimated population size. Of six models tested the most accurate underestimated by nearly half. The models give biased estimates most probably because not all animals on the survey line were sighted . (3) Aerial strip transect surveys were also negatively biased. The extent of this bias was estimated in index-removal experiments. Experiments were carried out on two populations in areas of differing obstructive canopy cover. (4) In woodland habitat with a canopy cover of 30- 60%, a correction factor of 3.2 was required to take account of animals not seen. In forest habitat with a canopy cover of 60-100%, a correction factor of 4.9 was required. (5) Using these results, the population size of feral buffalo, cattle and horses in Kakadu National Park was estimated by aerial survey at the end of each year over 6 years. Annual rates of increase for three regions of the Park were estimated, taking into account known removals from the population. The effects of dry season rainfall and population density in the preceding year on rate of increase were examined for each species. (6) The mean annual exponential rate of increase for each species was 0.10 yr-1 for buffalo, 0.23 yr-1 for cattle and -0.14 yr-1 for horses. (7) The annual rates of increase varied greatly between years within all species and were highly correlated with dry season rainfall in the year of survey for buffalo and cattle but not for horses. (8) No significant effect of preceding density on rate of increase was found for any species. A large reduction in buffalo populations did not correspond with an increase in unharvested populations of horses, suggesting the two species do not compete for food or other resources. (9) A campaign to control populations of feral water buffalo in Kakadu National Park was assessed. Between 1979 and 1988, approximately 79,000 animals were removed, 54% by commercial live-capture, 35% by shooting from helicopters and 10% by shooting from the ground. (10) In the period 1983-1988 when population estimates from aerial survey are available, mean buffalo population density was reduced from 5.60 km-2 to 1.17 km-2 over the surveyed area of the Park. (11) The costs of removal by shooting from helicopters, capturing animals alive and shooting from the ground were compared. The mean costs per animal in 1988 were $24.13, $74.53, and $86.02 respectively. (12) The effects of initial density and time spent shooting on number of animals removed by shooting from helicopters were examined. One linear and two curvilinear models were fitted to data from four different removal exercises. The relationship between time spent shooting and number removed was best described by a curvilinear (Ivlev) function. This model was used to estimate costs of control to a specified density. (13) Model regression coefficients differed between removal exercises, suggesting that the number removed may be affected by variables other than time spent shooting and initial density. Data from the range of conditions encountered during removal is thus likely to be required for robust estimation of removal costs.

Ambystoma macrodactylum (long-toed salamander) and A. gracile (northwestern salamander) are two common salamander species occupying key trophic positions in mountain ponds of Mount Rainier National Park. The objective of this research was to document and evaluate the distributions and abundances of the two species, relative to habitat characteristics of ponds in the park. Amphibian distributions and abundances were assessed in 20 ponds from June through September 1993 to 1996. Nutrient concentrations (total nitrogen, Kjeldahl-N, total phosphorus, and orthophosphate-P), habitat characteristics (surface area, depth, elevation, substratum organic content lost on ignition, amount of coarse woody debris, aquatic vegetation, and bottom firmness), and water quality (temperature, dissolved oxygen, alkalinity, conductivity, and pH) were measured. Distinct habitat associations were found for each Ambystoma species. Ponds with one species only were different in surface area, maximum depth, substratum organic content, and elevation. Ponds with A. macrodactylum were small, shallow, high in elevation, and had firm sediments low in organic matter relative to A. gracile ponds. Ambystoma macrodactylum ponds typically contained little coarse woody debris relative to the amount of aquatic vegetation. Ambystoma gracile ponds were large, deep, low in elevation, had flocculent sediment high in organic content, abundant coarse woody debris, and little aquatic vegetation relative to A. macrodactylum ponds. Two ponds supported reproducing populations of both species and exhibited habitat characteristics intermediate to the allopatric pond types. These findings suggest that habitat complexity plays an important role in the segregation of A. macrodactylum and A. gracile. / Graduation date: 2000

There have been reports that rainfall in East Africa is changing or becoming more variable. This can have significant implications for conservation initiatives and the food security of this populace region that is heavily reliant on the rain fed agricultural system. The perceptions of farmers regarding rainfall along with 30 years of satellite data and 16 years of ground level observations were analyzed in order to characterize rainfall in and around Kibale National Park, a protected area in the Ugandan portion of the Albertine Rift. Two homogenous rainfall regions exist in the area, and the onset, cessation, and amount of rainfall during seasons is highly variable. The perceptions of farmers align with the analysis of rainfall data, indicating that the season beginning in March shows the highest degree of variability. Decreases in the amount of rainfall are found for both rainy seasons.

Point Pelee National Park in Ontario, Canada has been affected by a long history of human activity. This activity has encouraged the establishment of approximately 276 exotic invasive plant species. These plants decrease biodiversity and effective function of ecosystems within the Park. A 5 Year Exotic Plant Species Management Plan for the Park was written in 1990. Since that time inventories have been done on some of the species but a monitoring of all the high priority exotic invasive plants has not. As part of this study an inventory of the high priority exotic invasive plants and their spatial extent in the Park, was created. From May to September, 2011 a comprehensive inventory took place within a 5.5km stretch in the terrestrial area at the southern end of the Park. Systematic belt transects were performed, on foot, from west to east at 100 m intervals. Within the quadrats percent cover of each plant species was determined. The data collected in the field were compiled using geographic information systems (GIS), resulting in maps of the extent of the most abundant species studied. Analysis as part of this study included using the data to determine which plants and areas are higher priorities for management within the Park. Quadrats were analysed for diversity using the Simpson Index and, since the data was non-parametric, comparisons were made across diversity and native richness using the Kruskal Wallis test. Alliaria officinalis is the only non-native species that is widespread within the study area. Other non-native species with a high potential for invasiveness were observed but only consisted of a few individuals along roads and paths. Some non-native species were present along or near roads and paths in denser patches (17-100% plot coverage). Recommendations include removal of some non-native species deemed to be a potential threat to native richness and diversity, followed by re-vegetation with native species, and continued monitoring. Future restoration efforts are best directed at the area around DeLaurier, along west beach and at the Tip. These areas have the lowest diversity and native richness and therefore need the most improvement.