Planet Earth is undergoing a rapid rate of ecosystem conversion and degradation and one of the major challenges of current environmental science is to contribute to the management and conservation of biodiversity through the development of tools for assessing environmental change. The main goal of this doctoral dissertation is to contribute to the scientific literature on remote sensing tools for monitoring tropical dry forests, which is one of most important global change frontiers. This thesis is composed of five chapters which have the goals of covering the following specific goals: 1) To estimate the extent and geographic distribution of the neotropical dry forest. 2) To evaluate the potential use of satellite-detected fires as deforestation predictors in tropical dry forest and 3) To evaluate the potential of remote sensing techniques to detect edge effects in tropical dry forest. Before assessing the main goals of the thesis, in chapter two, Integrating Remote Sensing and Biodiversity research, we stress out the necessity of integrated assessments using multiple spatial and spectral resolution sensors over a wide array of ecosystems in order to find relevant ecosystem properties that would be sensitive to species richness. Chapter three, Extent and Conservation of tropical dry forests in the Americas, describes a regional scale mapping effort using coarse-scale imagery (MODIS 500-m) of the extent and geographical distribution of tropical dry forests that introduces several innovations to previous assessments. Based on these techniques, the total current extent of tropical dry forest in the Americas is 519,597 Km2. I also found that 66% of the ecosystem has been already converted to other land uses while only 4.5 % of is under protected areas. Chapter four, MODIS Active fires and deforestation in tropical dry forest landscapes, we show correlations patterns between the number of MODIS Active Fires and forest cover change in four tropical dry forest landscapes in Latin America. At the Santa Cruz site (Bolivia), correlations were strong and significant while at Chamela Site (Mexico) and the Mata Seca site (Brazil) correlations were moderate but significant as well. In the Machango site (Venezuela), active fires showed no correlation to deforestation events. In general, our findings show that fires detected by the MODIS sensor may be used as predictors of deforestation in tropical dry forest ecosystems. Chapter five, Edge influence on canopy openness and understory microclimate in two Neotropical dry forest fragments, addresses one of the most characteristic features of fragmented tropical forests: the increase in disturbance near the edges of the fragment or what is known as edge effects. Results in gap fraction and Fraction of Intercepted Photosynthetically Active Radiation (FiPAR) show that edge influence at tropical dry forest sites extend to at least 300-m. Finally, Chapter Six, Remote sensing of edge effects in dry forest fragments using CHRIS/Proba Imagery, shows an assessment of changes in the fraction of intercepted photosynthetically active radiation (FiPAR) across four edge-to-interior transects in tropical dry forests fragments and their correlation to spectral vegetation indices (SVIs) computed from the hyperspectral and multiangular CHRIS sensor on board the Proba platform. Results show that the use of spectral vegetation indices for identifying and quantifying edge effects in tropical forests have the potential to improve modeling of forest disturbance in fragmented landscapes. The work contained in these five chapters address issues that are critical to the advancement of tropical dry forest monitoring. These studies contribute to the current scientific literature on the use and application of optical remote sensing tools, not only applicable in tropical dry forests, but for tropical forest conservation at the continental, regional and local level.

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1990. / Includes bibliographical references (leaves 161-170) / Microfiche. / xv, 170 leaves, bound ill., maps 29 cm

An investigation into the effects of deforestation and habitat fragmentation on a central Amazonian frog community was carried out on the Biological Dynamics of Forest Fragments Project, (BDFFP) based in Manaus, Amazonas, Brazil. Three aspects of deforestation were investigated: the effects of fragmentation and reserve size, the influence of matrix habitat and the effects offorest edge on frogs in 10- hectare isolates. Very few frogs species were lost from fragments (regardless of size) following fragmentation and isolation for 7-10 years. Instead, frog species richness increased, with an average increase in 10 species per fragment. The increase in species was brought about by an increase in matrix associated species, some of which were present in the absence of their preferred breeding habitat. Different frog species had varied responses to fragmentation. The abundance of Eleutherodactylus fenestratus, a terrestrial breeder, increased significantly as fragment size decreased, and its abundance was significantly higher in both large and small fragments than in continuous forest. Colostethus stepheni, a semi-terrestrial breeder, was less abundant in fragments than continuous forest. Finally, Eleutherodactylus zimmermanae and Osteocephalus sp.A did not differ significantly in abundance among fragments, or between fragments and continuous forest. Multiple regression analysis indicated that variation in litter depth and canopy cover may explain the observed increase in E. fenestratus abundance in small fragments. Breeding success of pool breeders attracted to artificial pools was variable, but there was no evidence of reduced breeding success in fragments relative to primary forest. Overall, fragmentation appeared to affect the frog community less severely than other taxonomic groups. Species richness in tropical forest remnants showed a tendency to increase as a result of fragmentation, and only one of four species exhibited lowered abundance in fragments. The effects of fragmentation and subsequent small isolated populations of frog species in fragments was alleviated somewhat by the ability of central Amazonian frogs to utilise matrix habitat. Litter frogs, wallow breeders and upland forest pool breeders all displayed an ability to permeate, and in most cases become residents of matrix habitat. Both matrix with a history of cut and burn and matrix which was only cut supported a similar frog community. Thus, for central Amazonian frogs isolates were not truly isolated due to the ability of frogs to utilise matrix habitat. Litter frogs in 10- hectare isolates displayed an independence from edge related abiotic and biotic gradients. This independence was true for frog species richness, abundance and composition. Consequently, forest fragments are in effect larger for frogs than for other taxa who are constrained by edge effects to exist only within the core of large fragments. Colostethus stepheni was one species found to be negatively affected by habitat fragmentation. Abundance of Colostethus stepheni was significantly lower in fragments and matrix habitat compared to primary continuous forest. This species was also found to be sensitive to edge, with higher abundances recorded as distance from the edge increased. The community level approach adopted in this study, as opposed to intensive investigation of single species, may well have overlooked other' sensitive' species which show more subtle responses to habitat fragmentation than that of Colostethus stepheni. The ability to use matrix and the relative independence from edge related phenomena accounts for the resilience of central Amazonian frogs in a disturbed and fragmented landscape. However, with respect to matrix habitat, forest surveyed in this study has not been repeatedly cut or cut and burnt (with the exception of pasture-land where the frog community is depauperate). In other areas of the Amazon, away from the experimental plots of the BDFFP, matrix habitat is destroyed more frequently. More work is needed to determine the ability of central Amazonian frogs to utilise matrix habitat which is disturbed more frequently.

Thesis (M. Appl. Sc.) -- Lincoln University, 2008. / Also available via the World Wide Web.

Thesis (M.A.)--Ohio University, June, 2008. / Title from PDF t.p. Includes bibliographical references.

Thesis (M.A.)--Ohio University, June, 2004. / Includes bibliographical references (p. 107-111).

Thesis (Ph. D.)--University of Tennessee, 1998. / Vita. Includes bibliographical references (leaves 103-108).

Thesis (Ph. D.)--University of Maryland at College Park, 1996. / Includes bibliographical references (leaves 118-126).

Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2007. / Dr. Curry, Judy, Committee Member ; Dr. Webster, Peter, Committee Member ; Dr. Weber, Rodney, Committee Member ; Dr. Ingall, Ellery, Committee Member ; Dr. Robert Dickinson, Committee Chair.

Thesis (M.A.)--Ohio University, June, 2004. / Title from PDF t.p. Includes bibliographical references (p. 107-111)