Metropolitan New Orleans Neighborhoods were surveyed in order to determine how bird populations responded to distance from the batture, percent canopy cover, stem counts, and understory vegetation. Surveys were conducted in the spring and summer of 2010. It was found that batture birds, urban birds, and pooled birds all had greater species richness and abundance in the spring in areas with more canopy cover, higher stem counts, more understory vegetation, and distances closer to the batture. In the summer, batture birds had greater richness and abundance in areas with more canopy cover, higher stem counts, and more understory cover. This group of birds also had greater richness nearer the batture in the summer, but there were no significant abundance tests. Urban birds showed no preferences for any of the vegetative variables, but showed some tendency to have greater richness further away from the batture. Pooled birds did not significantly respond to any of the variables during the summer. Fifteen individual species of birds were also analyzed to see how they responded to the same variables.

There has been a critical decline in grassland bird populations due to habitat fragmentation and deterioration, and suppression of natural fires. Alteration of the disturbance cycle may lead to changes in vegetation structure and thus habitat suitability for breeding grassland birds. Management practices at the Mississippi Sandhill Crane National Wildlife Refuge, including the use of prescribed fire, are in need of evaluation. My study asked what frequency of prescribed burns is necessary to support breeding grassland birds and whether vegetation structure varies among burn units. In this study, bird abundance and species richness did not differ significantly among burn units and vegetation cover-type was not a strong predictor of these factors either. There was evidence of site utilization by breeding grassland birds immediately following a burn, which suggests that the bird community is able to recovery quickly post-fire and these units may serve as viable habitat for breeding grassland birds.

Philosophiae Doctor - PhD / The Cape Floristic Region (CFR) of southern Africa is one of the world’s most unique biodiversity hotspots. However, this biodiversity continues to be threatened by habitat loss due to rapid urbanisation, agriculture and alien vegetation encroachment, and now, by future groundwater extraction and climate change. Previous work had shown that soil moisture is important in structuring wetland plant communities at fine-scale. What is not fully known, however, is how the spatial distribution of species at a local scale is related to soil hydrology and what the response in the future of species distributions will be to perturbations arising from changes in climate or subsurface moisture in the future. The current research investigated the water regime of the Restionaceae which is a key family in the Fynbos biome and the implications of possible changes in soil hydrology caused by climate change in communities within this region. The Restionaceae were particularly appropriate because they are shallow rooted perennials with the ability to tolerate a wide range of water regimes which allows them to successfully co-habit within mixed plant communities as segregated clusters along fine-scale hydrologic gradients. Vegetation survey counts for the presence of these species along with measurements of soil water table depth and moisture content data generated from eight small-scale plots (50 x 50 m) were used to investigate the possible hydrological niches and to envision the potential impacts of a substantial reduction in rainfall and an increase in temperature as projected by Global Climate Models (GCMs) on the structure of Restionaceae communities in seasonal wetlands by 2100. A comparative analysis of the effects of two extreme Representative Concentration emission Pathways (RCP2.6 and RCP8.5) on significant hydrological variables to plant water regimes was carried out. The IPCC AR5 report describes the RCP8.5 emissions scenario as the likely ‘business as usual’ scenario where emissions continue to rise through the 21st century while the RCP2.6 scenario assumes that emissions peak between 2010 and 2020 and substantially subside thereafter.

A research report submitted to the Faculty of Science in partial fulfilment of the requirements for the degree of Master of Science. Johannesburg, 31 August 2012. / Unable to load abstract.

Centre of African Ecology Animal, Plants and the Environmental Sciences University of the Witwatersrand, Johannesburg. / Arid African savannas experience seasonal, variable rainfall, resulting in unpredictable patterns in vegetation distribution. Understanding the spatio-temporal variability in primary productivity and the resulting behavioural responses of native herbivores is essential for the analysis of the vulnerability of savanna ecosystems to climatic and human-induced threats. The Central Kalahari Game Reserve (CKGR), Botswana, is open to free-ranging wildlife to its south and west. The mostly homogeneous dune landscape is interspersed with valley and pan systems, which deviate considerably from dune regions in their soil and vegetation structures. I assessed the phenology of green vegetation across the pan-valley and dune habitats of the northern CKGR, using Normalized Difference Vegetation Index (NDVI) imagery, and related variations in greenness to the ecology of gemsbok (Oryx gazella), a herbivore species that is highly adapted to arid conditions. Eight female gemsbok were collared in the northern CKGR, and their patterns of habitat selection and responses to three greenness measures (NDVI, ΔNDVI and Relative Greenness) were assessed using logistic regression models. Gemsbok 12-hour displacement distances for each herd were compared seasonally to assess whether gemsbok in the northern CKGR differ in their movement strategies depending on the prevailing environmental conditions at that point in time and space. The northern CKGR experiences high inter-annual variability in NDVI greenness and phenology. Pan-valley and dune habitats did not have significantly different rates of green-up or green season durations, but dune habitats had higher NDVI levels. Patches with the highest greenness levels showed little spatial persistence from year to year. Gemsbok did not select for higher NDVI or ΔNDVI, but they selected for categories of relative greenness that were higher than the lowest relative greenness level. Gemsbok selected pan-valleys over dunes during the green season, but were not selective during the brown season, probably as a result of the loss of green grasses in pan-valley habitats during this period. Finally, gemsbok had no specific general trend in seasonal displacement distances. Gemsbok in the CKGR are likely to be opportunistic feeders, and herds probably made varying behavioural decisions based on their immediate environmental conditions.

Implementation of the National Water Act in South Africa requires that an ecological Reserve be determined for all significant resources. The ecological Reserve determination is the estimation of the amount of water required to maintain the system in a particular ecological condition. Because aquatic habitats are defined in terms of local hydraulic variables rather than amounts of water, hydraulic analysis provides a crucial link in relating hydrological conditions and river ecosystem integrity. Over the last decade, considerable effort has been devoted to developing hydraulics for the Reserve determination. The hydraulics needs for Reserve determination are primarily for low flow analysis, and appropriate methods still need to be developed. This thesis deals with hydraulics under low flow conditions. Its emphasis is on developing appropriate methods for describing the hydraulic characteristics of South African rivers under conditions of low discharge, and the influence of vegetation and large bed roughness. The following methods have been developed: · A new equation for prediction of overall flow resistance under large-scale roughness, and a new approach for estimation of intermediate-scale roughness resistance that distinguishes the influences of large and intermediate scale roughness components. · Prediction methods for velocity distributions with large roughness elements. Under low flows, rocks and boulders may control the local velocity and depth distributions. Distributions of velocities and depth are related to rapidly spatially varied flow caused by the boundary geometry rather than flow resistance phenomena. With increasing discharge, the multiple local controls become submerged and the flow tends towards a resistance controlled condition. Available information addressing the distinction between resistance controlled and multiple local controls conditions is limited. This thesis contributes to understanding the transformation between multiple local controls and the resistance controlled conditions. · Practical conveyance prediction methods for three situations pertaining to the occurrence of vegetation in rivers and wetlands. In-channel and riparian vegetation makes an important contribution to the creation of physical habitats for aquatic animals, but also has significant effects on flow resistances that need to be predicted.

Student Number : 0216831W - MSc research report - School of Environmental Sciences - Faculty of Science / This report deals with the relationship between the NDVI obtained from the NOAA AVHRR sensor and that obtained from the MODIS sensor. The relationship is quantitatively assessed for distinct polygons over various land-cover types in the northeastern Kwa-Zulu Natal Province of South Africa. Spatial and temporal variations in the relationships are addressed and discussed with reference to spectral response, sunsensor- target geometries and atmospheric factors. Specifically, various methods are investigated to estimate a MODIS-equivalent NDVI from the AVHRR NDVI and in so doing create the potential to develop a self-consistent NDVI between the historically available AVHRR NDVI dataset and the relatively new MODIS NDVI dataset. NOAA-16 AVHRR NDVI data and AQUA MODIS NDVI data for the two-year period from January 2002 to December 2003 are used to develop the method. A linear relationship exists between the AVHRR and MODIS NDVI. However, spatial variations in the relationship in terms of land-cover and mean NDVI are pointed out. The potential of atmospheric corrections applied to AVHRR data through a radiative transfer atmospheric correction model to improve the relationship between the two NDVI datasets is also investigated. The importance of geo-location accuracy of the AVHRR NDVI dataset is assessed in the light of the accuracy obtainable with the proposed method to estimate a MODIS-equivalent NDVI from the AVHRR NDVI. A method to estimate the MODIS NDVI from the AVHRR NDVI that takes the mean AVHRR NDVI value into account, as opposed to a constant linear relationship over all the points, is proposed. Atmospheric correction is shown not to improve the accuracy of the method in a statistically significant way. The root-mean-square error of the proposed method is in the order of 0.05 NDVI units and varies between 0.5 and 2 standard deviations of the MODIS NDVI over an entire season.

Shortened periods of inundation due to water management have led to the encroachment and expansion of Carolina willow (Salix caroliniana) in sawgrass (Cladium jamaicense) marsh communities. Morphologic and physiologic differences between sawgrass and willow have potential consequences for microhabitat conditions and ecosystem function such as a reduction in temperatures and light availability and changes in primary productivity. Since it is a woody shrub, willow is often assumed to exhibit higher rates of transpiration than non woody plants, which in turn can affect photosynthesis and carbon exchange and ultimately wetland water management. In this study willow was found to have higher rates of stomatal conductance (gs) and photosynthesis (Anet) than sawgrass. However, sawgrass had greater intrinsic water use efficiency (WUE) than willow. This suggests that willow is capable of greater gas exchange and carbon assimilation than sawgrass but requires more water. Understanding the implications of willow expansion will improve landscape models of wetland water and carbon exchange and inform water management decisions. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

Orientador: Marcos César Ferreira / Banca: Sergio dos Anjos Ferreira Pinto / Banca: Diana Sarita Hamburger / Resumo: O processo de erosão acelerada se apresenta como um dos maiores problemas ambientais da atualidade, influenciando a produção agrícola, devido às conseqüências no empobrecimento do solo e no abastecimento de água, diminuindo a sua disponibilidade em reservatórios. Este trabalho apresenta uma proposta para avaliação da ambiental das variáveis relacionadas ao desenvolvimento de processos erosivos além da verificação da adequação do uso e ocupação do solo as necessidades especiais da área, tendo como estudo de caso a Bacia do Córrego Santo Antonio, situada no município de Jaú-SP. Propomos como indicador quantitativo da cobertura vegetal, os índices de vegetação (IV) obtidos por meio de imagens de satélite. Na avaliação da suscetibilidade à erosão nos amparamos no modelo da EUPS o qual foi desenvolvido para obtenção de uma classificação das terras da bacia em classes de risco de erosão além da obtenção classes de capacidade de uso relativas a cada unidade pedológica. O estudo relativo a analise da viabilidade da utilização do IV, foi embasado na amostragem de campo a partir da qual se obteve os valores médios de percentual de interceptação das gotas de chuva para determinados tipos de cultivo na região. Avaliamos ser possível o emprego do índice de vegetação em estudos referentes à proteção do solo e acreditamos serem as classes de risco á erosão um importante indicador das necessidades de planejamento ambiental. Verificamos uma mudança no uso do solo da área do ano 2000 para ao ano 2003, o que provocou grandes alterações nos resultados da adequação do uso do solo na bacia do córrego Santo Antonio. / Abstract: The soil loss process arises as one of the major environmental problems nowadays, influencing the agricultural production, due to its consequences on the soil decay and on the water supply, decreasing its availability in the reservoirs. This work presents a proposal for the assessment of the environmental aspect of the variables concerning the development of the soil loss processes besides the verification of the adequacy of the use and occupation of the land regarding the special necessities of the area, portraying as study of case the Santo Antonio watershed, located in the town of Jaú, São Paulo. We propose as the quantitative indicator of the vegetation covering, the vegetation indexes ( VI) obtained through satellite images. On the assessment of the soil loss susceptibility we looked for support on the USLE, which was developed to obtain a classification of the watershed lands in classes of soil loss risk, besides obtaining classes on the capability of use regarding each pedologic unit. The study about the analysis of the viability of the use of the vegetation index was based in the field samples, from which were achieved the average percentage values of rain drops interception for determined kinds of agricultural growing in the region. We assessed that it is possible to proceed the use of the vegetation index in studies concerning the soil protection, and we believe that the classes of risk regarding soil loss are an important indicator towards the necessities of environmental planning. It was verified a certain change on the land use in the area from the year 2000 until the year 2003, what brought huge alterations on the outcome of the land use adequacy in the Santo Antonio watershed. / Mestre

O objeto desta pesquisa são os efeitos da vegetação nas condições microclimáticas urbanas, partindo-se da premissa que a presença da vegetação influencia o microclima do seu entorno imediato. A partir de diferentes formas de distribuição das áreas verdes na cidade e com o uso de espécies locais, o objetivo é quantificar a intensidade e a distribuição espacial dos efeitos microclimáticos da vegetação, principalmente as alterações de temperatura do ar e superficial no nível do pedestre, utilizando-se modelos de balanço de energia e ferramentas computacionais. Foram feitas simulações paramétricas no ENVI-met a fim de investigar o efeito da distribuição de áreas verdes (linear, grandes massas verdes concentradas ou pequenos agrupamentos distribuídos em diferentes distâncias) e por meio das medições de campo pode-se quantificar a importância da vegetação (gramíneas, arbustos e arbóreas) nos aspectos climáticos. Os resultados mostram que o efeito da vegetação é local e não ocorre uma influência significativa muito além dos limites das áreas verdes. Em relação à intensidade do efeito da vegetação, a diferença média entre as temperaturas do ar nas áreas verdes arborizadas e as ruas adjacentes é de 1.5ºC. Já o sombreamento pelas árvores de copa densa (LAI=10), mostrou diferenças médias de 23ºC, nas temperaturas superficiais do solo, embaixo da copa. Esse resultado indica que o uso das árvores é uma estratégia para amenizar o efeito de ilha de calor nas metrópoles, pois evita o aquecimento de materiais como asfalto e concreto e a liberação da radiação de onda longa acumulada durante a noite. / The main purpose of this research is the effects of vegetation in urban microclimate conditions, under the premise that the presence of vegetation influences the microclimate and its surroundings. Considering different forms of green space distribution and using native species, it could quantify the intensity and spatial distribution for the microclimate effects by a vegetated area. The modifications of air temperature and the surface temperature at the level of the pedestrians were analyzed based on energy balance and computer models. Parametric simulations on ENVI-met were done to investigate the effect of green areas distribution (linear forms, large mass of vegetation and small groups of trees) and were compared with on-site measurement data. The simulation results showed the impact of urban vegetation for climatic aspects. The outputs indicated that the vegetation effect is local and do not have a significant influence beyond the limits of the green area. Regarding to the intensity of vegetation effect, the average difference between air temperature under the trees and above the streets is 1.5ºC. While the shadowing of a dense tree (LAI=10) showed an average difference of 23ºC for superficial temperatures between green spaces and the street. This result pointed out that green area is an important strategy to mitigate the heat island effect in city centers, as it can prevent asphalt and concrete from heating and releasing long wave radiation during night time.