The Florida Everglades ecosystem is threatened by human development, increased pollution, freshwater scarcity, and invasive species; factors that have negatively impacted the Everglades and native species health and populations. Man-made canals and levies have redirected the natural flow of fresh water from Lake Okeechobee into the Florida Everglades, starving central and south Florida ecosystems of necessary fresh water and nutrients. Through the efforts of the Comprehensive Everglades Restoration Project (CERP), freshwater is being redirected back into central and south Florida, returning the sheet flow of water back into the Everglades. Monitoring species abundance in the Everglades is a beneficial conservational tool for assessing restoration efforts from CERP. As a semi-aquatic apex predator, river otters (Lontra canadensis) are a useful health bio-indicator for the Florida Everglades. In order to conduct future population studies of river otters in the Florida Everglades, it must first be ascertained where they can be found and what time of year they are most likely to be sighted. For this study, Moultrie infrared game cameras were used to photograph the presence or absence of river otters within the five main habitats in the Everglades; the pinelands, hardwood hammock, cypress swamp, marsh prairie, and mangrove estuary at two protected areas in the Florida Everglades (Big Cypress National Preserve and Fakahatchee Strand State Park). River otters were most frequently sighted in the hardwood hammock habitat, but were also found in the cypress swamp. The large majority of river otter sightings occurred during dry season, which is thought to be a function of restricted water availability and aquatic mobility. Future population studies of river otters would be most productive in the hardwood hammock and cypress swamp habitats during dry season. Game camera images along with field opportunistic sightings, resulted in a variety of species documented. This provided valuable information of species richness and distribution within and amongst the habitats. The hardwood hammock was found to be the most species rich habitat, having over half the species observed in the study in this habitat. The Aves class was the most abundantly observed in the Everglades, and was most frequently sighted during the dry season. As a refuge for migratory birds, the Everglades house the majority of bird species during the winter months, which occur during dry season. The Aves class was most frequently sighted in the pinelands habitat during dry season. This habitat, being the highest in elevation and therefore the driest, shows a stronger resemblance to most northern bird habitats then does the water-saturated wetlands found throughout the Everglades. The mangrove estuary was the most commonly occurring outlier, having the least species overlap when compared to the other habitats. All other habitats in the Everglades are freshwater wetlands, while the mangrove estuary is a brackish environment, which limits the species that are unable to tolerate saline conditions. Further studies of species abundance throughout the Everglades will aid in monitoring CERP restoration efforts over time.

MESHWR / Department of Hydrology and Water Resources / Lebalelo area of Sekhukhune district is one of many areas in South Africa experiencing portable water scarcity, especially during prolonged dry season. Due to the dominance of low yielding aquifers in South Africa, it is essential to manage groundwater resources in these low yielding aquifers. However, the management of low yielding aquifer is difficult in areas like Labelelo where the hydrogeological characteristics of the aquifers are understudied. This study investigated the hydrogeological characteristics of the aquifers in the area using combined geophysical method and analytical groundwater models. Four newly drilled borehole and five existing boreholes were used for this study. Geophysical survey was carried out using magnetic and electromagnetic methods. The magnetic survey was used to locate the position of magnetic bodies such as dolerite dykes and different lithologies with different magnetic properties. The electromagnetic survey however, was used to determine zones of high permeability associated with the intrusive bodies as well as high permeability zones in fault planes. Step test, constant discharge test and recovery tests were conducted on all the boreholes to stress the borehole. This was used to determine a suitable and sustainable pumping rate of the aquifer. Pumping test data from the pumping period and recovery was evaluated and interpreted using AQTESOLVE. Aquifer transmissivity, storativity, internal and external hydraulic boundaries were determined from the data. The transmissivity in the area ranges from 0.08 to 124.7 m2/day. The aquifer types in the area are double porosity aquifer, radial flow aquifer with single porosity. Inductive Coupled Plasma (ICP-MS) was used to measure heavy metals, trace metals and cations while Ion Chromatography (IC) was used to determine anions in groundwater of the study area. The groundwater in the area is dominated by calcium carbonate as a result of long residence time with dolomite. The hydrochemistry of the water indicates that the chemistry of the groundwater in the area is mainly controlled by rock-water interaction. / NRF

This thesis provides the measurements of 222Rn exhalation rates, 210Pb deposition rates and excess 210Pb inventories for locations in and around Ranger Uranium Mine and Jabiru located within Kakadu National Park, Australia. Radon-222 is part of the natural 238U series decay chain and the only gas to be found in the series under normal conditions. Part of the natural redistribution of 222Rn in the environment is a portion exhales from the ground and disperses into the atmosphere. Here it decays via a series of short-lived progeny, that attach themselves to aerosol particles, to the long lived isotope 210Pb (T1/2 = 22.3 y). Attached and unattached 210Pb is removed from the atmosphere through wet and dry deposition and deposited on the surface of the earth, the fraction deposited on soils is gradually transported through the soil and can create a depth profile of 210Pb. Here it decays to the stable isotope 206Pb completing the 238U series. Measurements of 222Rn exhalation rates and 210Pb deposition rates were performed over complete seasonal cycles, August 2002 - July 2003 and May 2003 - May 2004 respectively. The area is categorised as wet and dry tropics and it experiences two distinct seasonal patterns, a dry season (May-October) with little or no precipitation events and a wet season (December-March) with almost daily precipitation and monsoonal troughs. November and April are regarded as transitional months. As the natural processes of 222Rn exhalation and 210Pb deposition are heavily influenced by soil moisture and precipitation respectively, seasonal variations in the exhalation and deposition rates were expected. It was observed that 222Rn exhalation rates decreased throughout the wet season when the increase in soil moisture retarded exhalation. Lead-210 deposition peaked throughout the wet season as precipitation is the major scavenging process of this isotope from the atmosphere. Radon-222 is influenced by other parameters such as 226Ra activity concentration and distribution, soil porosity and grain size. With the removal of the influence of soil moisture during the dry season it was possible to examine the effect of these other variables in a more comprehensive manner. This resulted in categorisation of geomorphic landscapes from which the 222Rn exhalation rate to 226Ra activity concentration ratios were similar during the dry season. These results can be extended to estimate dry season 222Rn exhalation rates from tropical locations from a measurement of 226Ra activity concentration. Through modelling the 210Pb budget on local and regional scales it was observed that there is a net loss of 210Pb from the region, the majority of which occurs during the dry season. This has been attributed to the fact that 210Pb attached to aerosols is transported great distance with the prevailing trade winds created by a Hadley Circulation cell predominant during the dry season (winter) months. By including the influence of factors such as water inundation and natural 210Pb redistribution in the soil wet season budgeting of 210Pb on local and regional scales gave very good results.

Euclea undulata Thunb. var myrtina is a widely distributed shrub in South Africa. The roots are used by traditional healers for the treatment of diabetes. Research indicates that roots contain epicatechin, lupeol as well α-amyrin-3O-β-(5-hydroxy) ferulic acid. It was found that α-amyrin-3O-β-(5-hydroxy) ferulic acid inhibits α-glucosidase while epicatechin lowers glucose levels in the blood. Existing literature also indicates the presence of the naphthoquinone 7-methyl-juglone in the roots, although it was not detected in all cases. Due to its cytotoxic nature, 7-methyl-juglone poses a potential threat when E. undulata is used as medicinal treatment. In order to assist the effective and safe use of this plant as a treatment for diabetes, this project aims to determine whether the presence of these metabolites is seasonal. It further aims to contribute to more sustainable harvesting methods by investigating stems and leaves in addition to the roots for the presence of these metabolites. / Environmental Sciences / M. Sc. (Environmental Science)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Animal performance was evaluated in bovine cattle livestock systems using tropical pasture based diets through a meta-analysis process, which included a database of scientific articles, dissertations and theses. Data was tabulated and categorized identifying the scientific work, the experiment, animals, animal performance, pasture, supplements and grazing. The conversion efficiency of supplement use was evaluated in the studies containing control (no supplementation), and calculated as the change in average daily gain of individual weight (CoEfADGan) or area (ha, CoEfADGha) per kg of supplement offered. Data distribution from a general database was assessed. To analyze the factors affecting animal performance variables the general database was sub-divided into two sub-bases, rainy and dry season. To evaluate the factors affecting animal performance variables data was weighted by n treatments and analysis of variance and covariance was used. The average daily gain of body weight per animal (ADGan, 0.870 vs. 0.611 kg / animal / day) and per hectare (ADGha vs. 5.76. 4.59 kg / ha / day), as well as daily animal load per hectare (DALha, 1483 vs. 1211 kg / ha / day) were higher (P <0.05) during the rainy season than during the dry season. During the rainy season, ADGan was lower in the genus Brachiaria and superior in the Panicum (P <0.05), but the DALha and ADGha were higher (P <0.05) in Cynodon. In dry season, ADGan was lower (P <0.05) in the Brachiaria than in Cynodon and Panicum, and ADGha was higher (P <0.05) in Panicum. In both dry and rainy seasons, ADGan, ADGha and DALha increased linearly (P <0.01) with increasing levels of supplementation, which ranged from zero to 1.6% of live weight (LW). The ADGan increased linearly (P <0.05) and DALha decreased linearly (P <0.05), while ADGha was quadratically (P <0.05) related to the increased availability of herbage. Animal performance was linear and positively correlated with leaf: stem proportion from pastures (P <0.05), both in the rainy and dry seasons. During the rainy season the best responses in ADGan and ADGha were obtained from the use of protein supplement compared with supplemental energy or proteinated salt (P <0.05), while the use of energy supplement enabled a higher DALha (P <0,05). During the dry season, ADGha was not affected by supplement type, but the best responses were obtained for ADGan with energy supplement (P <0.05) while protein supplementation, either through proteinated salt or protein supplement, was associated with a higher DALha (P <0.05). During the rainy season animal performance was quadratically (P <0.05) related to live weight (LW) of animals, and ADGan maximized in animals weighing about 380 kg and ADGha maximized in animals weighting about 400 kg. In the dry season, ADGan and ADGha were linearly and positively related animal LW (P <0.05). Pasture neutral detergent fiber (NDF) content ranged from 46 to 82% in dry matter (DM) and was quadratically related to ADGan (P <0.05) being that maximum gain was obtained with NDF content around 66%. Crude protein (CP) of pasture ranged from 1.9 to 21.6% in DM and was linear and positively correlated with ADGan (P <0.05). The ADGan was linear and negatively associated with the value obtained by the ratio between the content (% DM) of total digestible nutrients (TDN) and CP of pasture (P <0.05). Nitrogen fertilizer was linearly (P <0.05) associated with increased DALha, both in the rainy and dry seasons. The CoEfADGan and the CoEfADGha decreased lineally (P <0.05) with increasing animal LW during the rainy season, becoming negative from around 360 kg. In the rainy season as well as in the dry season, both efficiencies were also negatively (P <0.05) related to the CP content of pasture, being also negative from 10% CP, and positive and quadratically (P <0.05) related to the leaf: stem ratio of the pastures. Highest efficiencies were observed with leaf: stem ratio 3.7:1. During the dry season EfCoGMD and EfCoGAD decreased (P < 0.05) with the increasing the value obtained by the TDN: CP supplement ratio, becoming negative from 4,3:1. In conclusion, the meta-analysis enabled the identification of beef cattle performance in tropical pastures showing that it is influenced in an integrated manner by factors associated with several features such as climate, pasture, animal, handling and supplementation. However, the degree to which each factor influences animal performance could be more accuratelly assessed if publications were standardized and contained essential information regarding more detailed methodological descriptions and basic statistical information. / Foi avaliado o desempenho animal em sistemas pecuários bovinos utilizando dietas à base de pastagens tropicais através de processo meta-analítico, que incluiu na base de dados artigos científicos, dissertações e teses. Foram tabulados e categorizados dados de identificação do trabalho científico, do experimento, dos animais, do desempenho animal, da pastagem, dos suplementos e do método de pastejo. A eficiência de conversão do uso do suplemento foi avaliada nos estudos contendo tratamento testemunha (sem suplementação), e calculada como a variação do ganho médio diário de peso individual (EfCoGMD) ou por área (EfCoGAD) por kg de suplemento ofertado. Foi avaliada a distribuição dos dados da base geral e, para analisar os fatores que afetam as variáveis de desempenho animal, a base geral foi subdividida nas sub-bases águas e secas. Para avaliação dos fatores que afetam as variáveis de desempenho animal os dados foram ponderados pelo n dos tratamentos e utilizado análise de variância e covariância. O ganho médio de peso individual (GMD, 0,870 vs. 0,611 kg/animal/dia) e o ganho por área (GAD, 5,76 vs. 4,59 kg/ha/dia), assim como a carga animal (CAD, 1483 vs. 1211 kg/ha/dia) foram maiores (P<0,05) no período das águas que no período das secas. No período das águas o GMD foi menor na Brachiaria e superior no gênero Panicum (P<0,05), mas a CAD e GAD foram superiores (P<0,05) no Cynodon. Nas secas, o GMD foi menor (P<0,05) na Brachiaria que no Cynodon ou Panicum, e o GAD foi maior (P<0,05) no Panicum. Independentemente do período do ano, o GMD, o GAD e a CAD aumentaram linearmente (P<0,01) com o aumento do nível de suplementação, o qual variou de zero a 1,6% do peso vivo (PV). O GMD aumentou linearmente (P<0,05) e a CAD diminuiu linearmente (P<0,05), enquanto o GAD foi quadraticamente (P<0,05) relacionado com o aumento da oferta de forragem total. O desempenho animal foi linear e positivamente relacionado com proporção folha:colmo das pastagens (P<0,05), tanto no período das águas quanto no período das secas. No período das águas as melhores respostas em GMD e GAD foram obtidas com o uso de suplemento protéico quando comparado com suplemento energético ou sal proteinado (P<0,05), enquanto o uso de suplemento energético possibilitou maior CAD (P<0,05). No período das secas o GAD não foi afetado pelo tipo de suplemento, mas as melhores respostas para GMD foram obtidas com suplemento energético (P<0,05) enquanto que a suplementação proteica, seja através de sal proteinado ou suplemento proteico, foi relacionada com maior CAD (P<0,05). No período das águas o desempenho animal foi quadraticamente (P<0,05) relacionado com o peso vivo (PV) dos animais, sendo o GMD maximizado com animais pesando em torno de 380 kg e o GAD maximizado com animais de 400 kg. Nas secas o GMD e o GAD foram linear e positivamente relacionados com o PV dos animais (P<0,05). O teor de fibra em detergente neutro (FDN) da pastagem variou de 46 a 82 % na matéria seca (MS) e foi quadraticamente relacionado com o GMD (P<0,05) sendo que o máximo GMD foi obtido com teor de FDN em torno de 66%. O teor de proteína bruta (PB) da pastagem variou de 1,9 a 21,6 % na MS e foi linear e positivamente relacionado com GMD (P<0,05). O GMD foi linear e negativamente associado com o valor obtido pela razão (relação) entre o teor (% na MS) de nutrientes digestíveis totais (NDT) e PB da pastagem (P<0,05). A adubação nitrogenada foi linearmente (P<0,05) relacionada com aumento da CAD tanto no período das águas como no período das secas. A EfCoGMD e a EfCoGAD diminuíram linearmente (P<0,05) com o aumento do PV dos animais no período das águas, passando a serem negativas a partir de em torno de 360 kg. Tanto nas águas como nas secas, ambas as eficiências também foram negativamente (P<0,05) relacionadas com o teor de PB da pastagem, passando a serem negativas a partir de 10% de PB, e positiva e quadraticamente (P<0,05) relacionadas com a relação folha:colmo das pastagens. Máximas eficiências foram observadas com relação folha:colmo em torno de 3,7:1. No período das secas a EfCoGMD e a EfCoGAD diminuíram linearmente (P<0,05) com o aumento do valor observado na relação NDT:PB do suplemento, passando a serem negativas a partir de 4,3:1. Em conclusão, a meta-análise possibilitou identificar que o desempenho de bovinos de corte em pastagens tropicais é influenciado de forma integrada por fatores associados às características do clima, das pastagens, dos animais, do manejo e da suplementação. Contudo, o grau de influência de cada fator seria melhor definido se as publicações nessa área de conhecimento fossem padronizadas e contivessem informações mínimas tanto em relação à descrição da metodologia como em relação à presença de informações estatísticas básicas.