The ant colony, known as a self-organized system, can adapt to the environment by a series of negative and positive feedbacks. There is still a lack of mechanistic understanding of how the factors, such as temperature and food, coordinate the labor of ants. According to the Metabolic Theory of Ecology (MTE), the metabolic rate could control ecological process at all levels. To analyze self-organized process of ant colony, we constructed an agent-based model to simulate the energy and population dynamics of ant colony. After parameterizing the model, we ran 20 parallel simulations for each experiment and parameter sweeps to find patterns and dependencies in the food and energy flow of the colony. Ultimately this model predicted that ant colonies can respond to changes of temperature and food availability and perform differently. We hope this study can improve our understanding on the self-organized process of ant colony.

This thesis examines the environmental damages done by humans, such as plastic pollution, harmful energy production, and habitat destruction, and the things we are doing to correct them. It analyzes the costs and benefits government policies such as the ban of plastic products, along with creative innovations such as a sea vacuum and a cannon that shoots fish. Are we doing enough to heal the damage we have caused? Furthermore, can we change our behaviors to prevent more damage in the future?

White-tailed deer (Odocoileus virginianus) commonly consume row crops, with yield losses often attributed to their browsing. Deer density and field morphology may predict yield losses within local areas. We sought to 1) determine the effects of deer browsing on corn and soybean yields and investigate if deer density or field morphology correlated to yield loss in western Kentucky, and 2) compare pellet-based distance sampling to game camera surveys to determine if a distance sampling technique could accurately estimate deer density during the growing season. Overall, deer reduced corn and soybean yields on one-half of surveyed properties. Deer density did not influence yield losses in either crop; however, field morphology correlated with soybean yield losses. Pellet-based distance sampling provided statistically similar estimates as our game camera survey technique; however, at the individual farm level distance sampling estimates proved unreliable. Inaccurate model parameter (i.e., defecation rates) and inability to detect pellet groups in dense vegetation complicated the reliability of distance sampling models. Overall, yield losses from deer occur in western Kentucky and may be a localized event. Finally, game camera surveys should be used over pellet-based distance sampling during the growing season until detection issues and inaccurate model parameters are solved.

Salinity (S) and temperature (T) control every facet of the eastern oyster (Crassostrea virginica) life cycle, principally reproduction, development, growth, and mortality. Previous studies conducted in in the Breton Sound (BR) and Barataria (BA) estuaries have reported differences in growth and mortality rates between the basins. In the present study, environmental conditions were synchronized to compare growth and mortality rates between basins at similar combinations of T and S. Results indicate that when T and S are the same (synchronized), seasonal oyster growth and mortality rates differ between BR and BA. Seasonal analyses revealed that as salinities increased in both estuaries, growth rates generally increased, while mortality rates generally decreased. These findings suggest that basin-wide adaptations to local environmental conditions may exist.

Global climate change is projected to impact multiple levels of biodiversity by imposing strong selection pressures on existing populations, triggering shifts in species distributions, and reorganizing entire communities. The Lower Guineo-Congolian region in central Africa, a reservoir for amphibian diversity, is predicted to be severely affected by future climate change through rising temperatures and greater variability in rainfall. Geospatial modelling can be used to assess how environmental variation shapes patterns of biological variation – from the genomic to the community level – and use these associations to predict patterns of biological change across space and time. The overall goal of this dissertation is to examine potential impacts of climate change on amphibian diversity in central Africa. Geospatial modeling is used to: 1) map the distribution of the amphibian fungal pathogen, Batrachochytrium dendrobatidis (Bd) in a biodiversity hotspot in Cameroon under current and future climate; 2) assess phenotypic and adaptive genomic variation in a widespread frog species, Phrynobatrachus auritus, in order to predict areas where populations may best adapt under climate change; 3) determine how amphibian community composition may shift with climate change and which areas may experience greatest loss of functional groups. Findings show that most Bd samples belong to a globally hypervirulent lineage. However, areas of highest predicted environmental suitability for Bd are predicted to shrink under warming temperatures. Within P. auritus, most phenotypic and genomic turnover occurred across known ecological gradients and are heavily influenced by seasonal precipitation. Current amphibian beta diversity is greatest throughout the Cameroonian highlands and forest-savanna ecotones flanking the central Congolian lowland forests. Greatest shifts in community composition under climate change are predicted to occur in coastal Cameroon and its eastern border whereas the greatest predicted loss of functional richness was in central Gabon. Overall, this dissertation shows that areas of elevated environmentally-associated phenotypic, genomic, and community turnover are associated with key ecological gradients. Regions predicted to experience high genomic mismatch, large shifts in community composition, and high loss of functional richness resulting from climate change may warrant conservation attention.

This study lends strong support to the idea that members of Bromeliaceae have undergone a recent adaptive radiation, and therefore show that, at least in part, diversity in the tropics is due to a fast speciation rate and that the tropics can be a "cradle" for new diversification and exploitation of varying ecological niches through the diversification of ecophysiological traits within a lineage.

The purpose of this genetic study of the Santa Ana Speckled Dace Rhinichthys osculus was three-fold. The first goal was to characterize the molecular structure of the mtDNA control region of R. osculus. An 1143 base-pair region of the mitochondrial DNA genome, which included the complete control region was sequenced for all individuals. Analysis of the sequence data revealed that the molecular structure of the speckled dace control region was similar to the molecular structure described for other vertebrate taxa. The speckled dace control region contains three major domains, which vary in base frequency as well as in the frequency of nucleotide polymorphisms. Domain II was observed to be the most conserved, and Domain I was the most variable domain of the control region, in agreement with studies of other vertebrate control regions. The second goal of this study was to ascertain the phylogeny of R. osculus in Southern California in relation to other speckled dace in California. Seventy-four specimens of R. osculus were collected from five different watersheds located in three geographic regions of California: Southern California, the Central California Coast, and the Eastern Desert of the Owens River valley. Phylogenetic analysis of sequence data revealed that the Santa Ana Speckled Dace is a genetically distinct population from R. osculus inhabiting the Central Coast or Eastern Desert regions, which both differ from the Santa Ana Speckled Dace by a genetic distance of more than 7 percent. The Santa Ana Speckled Dace inhabiting the watersheds of Southern California form a reciprocally monophyletic clade with respect to the Central Coast dace and the Eastern Desert dace, which are sister clades to one another. The third goal of this study was to describe the population genetics of R. osculus in Southern California. Population genetic analysis demonstrated that a high degree of geographic population structure exists for the Speckled Dace in California, with 96% of molecular variance attributable to regional differences through isolation by distance. A high degree of population structure also exists among populations within the Southern California region as well. It was found that 45% of molecular variance in the Santa Ana Speckled Dace is attributable to differences among tributaries. This study finds that the distribution of speckled dace in Southern California best fits a model of population structure by individual tributary, with episodes of localized population bottlenecks followed by sudden population expansion, most likely linked to climatic variation. It is proposed the Santa Ana Speckled Dace constitutes an Evolutionarily Significant Unit (ESU) that qualifies it as a separate subspecies on the basis that it is geographically separated from other populations, genetically distinct from other dace populations due to restricted gene flow, and possesses unique phenotypic characteristics. This information suggests conservation and management strategies for the speckled dace populations which remain in existence in Southern California.

The overwintering ranges of North American bird populations are shifting and the winter ranges of south Florida’s landbirds remain understudied. Expert-drawn range maps used for scientific studies and environmental public policy could therefore be depicting inaccurate ranges for many migratory birds. This study used citizen science data from eBird (2001–2017) to evaluate patterns in overwintering avian species richness and identify discrepanciesin expert-drawn species range maps for overwintering passerines in south Florida. Most of Florida’s overwintering bird species were sighted in south Florida. Of the species observed there between 2001 and 2017, 66% had range map discrepancies. Fifteen target species were examined in the present study and fourteen of them were sighted in south Florida throughout the winter. None of these were depicted on range maps as overwinterers. These results showed that current expert-drawn range maps likely misrepresent the current winter ranges of passerine species in south Florida.

Bibliography: leaves 217-238. / ix, 238 leaves ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Applied Mathematics, 1995?

Bibliography: leaves 132-153. / viii, 153 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Spatially explicit models and computer intensive analysis were employed to explore how processes acting at the individual level scale up to population dynamics when processes are variable in space as well as the consequences of sampling spatially complex variability for drawing conclusions from limited ecological data. Dispersal and variation in marsupial mortality and development in relation to habitat selection and quality were studied, while evaluating spatially explicit models. The study of dynamics models of tick populations on sleepy lizards considered the effect of spatial and temporal variability, and demonstrated that counting ticks is a poor indicator of tick abundance. The "virtual ecologist" model is a useful method for linking the output of spatially explicit population models to reality, and will be a valuable approach for improving the design of ecological field research on spatially complex landscapes. / Thesis (Ph.D.)--University of Adelaide, Dept. of Environmental Science and Management, 1999?