Urbanization

Urbanization and land development, climate change, pollution, the spread of invasive species, and sea level rise are unprecedented challenges that have led to 25% of avian species worldwide facing an elevated risk of extinction. Under rapidly changing environmental conditions, traditional population models are not ideal because they typically assume that demographic parameters are static in order to estimate the probability of species extinction over a chosen timeframe. This assumption disregards species’ potential to adapt to environmental change; adaptations which could alter not only a species’ extinction outlook but also its legal protection status. The goal of my PhD research is to re-evaluate the risk of extinction of one threatened species, the Wood Stork (Mycteria americana), by accounting for potential adaptation in the context of planned and predicted changes in the southeastern United States. Since the 1970s, Wood Storks have shifted the timing of their breeding season, expanded their range northward and into novel habitats in urban areas, and begun consuming non-native fishes. I investigate these observations by comparing the physiology and diet of Wood Storks nesting in the historical core of their U.S. range (tree islands in the flooded Everglades marsh) with storks occupying novel habitats in urban and temperate locations. Faster growth rate, improved body condition, and increased survival by nestlings in urban areas would be evidence that colonies on the leading edge of the species’ range may be capable of sustaining growth of the whole population. In a third and final chapter, I forecast nest abundance and distribution patterns in the entirety of the U.S. range given various hydrological scenarios. Increased Wood Stork population size and stability are recovery criteria which must be met before the species can qualify for removal from the federal Endangered Species List. More broadly, understanding Wood Stork response to human development in the Everglades illuminates general patterns in avian species response to extreme changes in landscape, and could serve as a framework for proactively incorporating evolutionary potential into the framework of Endangered Species Act recovery in other species which have a high adaptive capacity.

Urban green space plays a vital role in the stability of the environment. Green spaces are increasingly becoming an integral part of the efforts to promote sustainability because of the different areas of benefits they provide. Sustainable city ranking systems were used to identify the most sustainable urban extents within the US. Landsat TM 4-5 imagery and textural classification are used as techniques in identifying, classifying and analyzing urban green spaces within nineteen urban extents. Patch analyst was used to analyze the location, structure and fragmentation green spaces within each urban extent. The aim is to determine to what degree urban green spaces can be considered to be an integral part of the sustainability of sustainable urban extents across the US and ascertain whether or not more sustainable urban extents do have more urban green spaces. The results of the study have shown that urban extents that are ranked highly v on sustainable ranking systems do not necessarily have to have large proportion of green spaces. Results have also shown that urban extents that are ranked high on sustainable rankings will not necessarily be affected by increase in population or decrease in urban green space. Finally human modified green spaces have simple geometric shapes compared to natural unaltered green spaces that have more complex geometric shapes.

The rapid increase of urban growth is a major issue for many regions around the world, which result in astounding loss in farmlands and increase in population densities. It important that urban growth be monitored as it will aid the local government in implementing the appropriate measures for a growing population. The city of Boca Raton, Florida, is the case study for this research. A multi-temporal analysis is done of five Landsat satellite images over a thirty year time period, 1973-2002. Textural analysis was performed on each of the images, to delineate the urban areas. Three by-products resulted from the textural analysis: time series tinted overlays, dasymetric mapping and a series of animated maps, showing the movement of growth across the landscape through time. All the resulting products of the time series analysis were used to show the magnitude and direction of growth over time.