Aquatic ecosystems exhibit different vulnerabilities to anthropogenic disturbances. I examined this problem in the Upper Napo River Basin (UNRB), Ecuador. I ranked from 1 to 5 aquatic ecosystem uniqueness, health and threats. I stratified the basin into five Ecological Drainage Units (EDU), 48 Aquatic Ecological Systems (AES), and 203 macrohabitats. I found main threats (habitat conversion/degradation, land development, mining, oil industries, and water diversion) cover 54% of the UNRB, but have different scores and extents in each EDU. I assessed the health of 111 AESs, under three land use treatments, by analyzing the streamside zone, physical forms, water quality, aquatic life, and hydrology. Overall, health of AESs varied from 5 to 2.58, with 5 being the highest level of health. Threats and health of AESs were inversely related (F=34.119, P

The oxidation kinetics and mechanisms of commercial dyes by H202 and iron powder system were investigated in a well-mixed batch reactor. The three dyes studied are Reactive Red 120, Direct Blue 160 and Acid Blue 40. There are three major processes involved in the oxidation: iron powder dissolution to Fe2+, dye adsorption by iron powder and dye oxidation by Fenton's reagent. Dissolution of iron powder was the initial step of adsorption and oxidation of the dyes. Dye adsorption obeyed the Langmuir adsorption isotherm. Both dissolution and adsorption were favorable at pH 2.0 to 2.5. Oxidation by Fenton's reagent was the major process contributed to decolorization. The optimal pH ranged from 3.0 to 3.5. The optimal ratio of H202 to iron metal was 0.001 M to 1.0 g/L. The initial oxidation rate followed pseudo-first-order kinetics. The mechanisms of iron dissolution, dye adsorption and oxidation were proposed in order to explain the experimental phenomena.

This thesis tried to determine the socioeconomic contributions of a renewable-hybrid energy system in San Juanico, Mexico. It also tried to analyze if the hybrid system was designed based on sustainable development principles. A survey of 91 electrified homes was conducted in San Juanico to gather information on consumer satisfaction and data analyzed using simple means and group mean comparisons, with suitable tests as needed. A binomial probit model for two dependent variables was applied to survey data. An energy price-comparison exercise was conducted as well. Findings showed the hybrid system had suffered from weak institutional frameworks, low community participation and a lack of long-term system and financial planning. Although the system made improvements in quality of life, it had not been reliable and lacked organizational ability to supply rural electricity in a sustainable fashion.

Two protected areas: Royal Bardia National Park (RBNP) and Royal Suklaphanta Wildlife Reserve (RSWR) in the Western Terai, Nepal, are under threats due to present political turmoil, uncontrolled immigration, inefficient land reform policies and unsustainable resource use. I did a stratified random questionnaire survey of 234 households to determine how resource use patterns and problems influence conservation attitudes. Chi-square, Student's t, Mann-Whitney and Kruskal-Wallis tests, and multiple regression were used. There was spatio-temporal variability in resource use patterns and dependency. People were collecting eight and seven types of resources in RBNP and RSWR, respectively. However, people in RBNP were more dependent on resources than RSWR. In both areas, the problem of firewood is serious. The mean attitude score of RBNP (8.4 ± 1.44) was significantly higher than the score of RSWR (7.7 ± 1.66; t = 3.24, p = 0.0007). Conservation attitude was determined by variables such as participation in trainings, wildlife damage, and satisfaction towards user groups.

A comprehensive forensic investigation of sensitive ecosystems in the Everglades Area is presented. Assessing the background levels of contamination in these ecosystems represents a vital resource to build up forensic evidence required to enforce future environmental crimes within the studied areas. This investigation presents the development and validation of a fractionation and isolation method for two families of herbicides commonly applied in the vicinity of the study area, including phenoxy acids like 2,4-D, MCPA, and silvex; as well as the most common triazine-based herbicides like atrazine, prometyne, simazine and related metabolites like DIA and DEA. Accelerated solvent extraction (ASE) and solid phase extraction (SPE) were used to isolate the analytes from abiotic matrices containing large amounts of organic material. Atmospheric-pressure ionization (API) with electrospray ionization in negative mode (ESP-), and Chemical Ionization in the positive mode (APCI+) were used to perform the characterization of the herbicides of interest.

In this study, the relationships between the time since last fire and the contributions of two palm species (Silverpalm, Coccothrinax argentata and Key Thatch Palm, Thrinax morrisii) to the burnable fuel load in the lower Florida Keys were examined. The population size distributions, effects of fire and plant size on mortality, annual growth rate, minimum reproductive size, and leaf moisture content of the palms were also determined. Regression models were developed to estimate the live and attached dead burnable biomass for both palm species. Equations with crown area and number of leaves as independent variables best predicted the amount of burnable biomass. Fuel accumulation was then modeled to determine the time until different biomass components begin to stabilize after fire. Live palm biomass continued to increase for approximately 2-5 years after fire, while dead attached biomass continued to increase for up to 15-20 years. In the burned sites a greater percent of mortality was observed in the larger palms.

The purpose of this research was to determine what challenges small-scale organic farmers face in choosing their particular production, marketing, and organizational strategies in Miami-Dade County. Rapid soil assessments were used on six organic farms to determine the effects of soil nutrient management in terms of pH, soil organic matter (SOM), and phosphorus (P). Potential costs of inputs were documented for each farm to determine the largest challenges facing the profitability of organic farms. A production, marketing, and organizational analysis determined how farmers shape their inter-farm competitive and cooperative relations. Preliminary findings from soil, input, labor, marketing, and organizational factors indicate that soil health varies dramatically from farm to farm, inputs and labor constitute significant costs, and marketing, production, and organizational strategies show no signs of immediate growth.

The Maya of the Yucatan region have a long history of keeping the native stingless bees (subfamily Meliponinae). However, market forces in the last two decades have driven the Maya to favor the use of invasive Africanized honey bees (Apis mellifera scutellata) for producing large quantities of high quality honey which has an international market. Furthermore, the native bees traditionally used by the Maya are now disappearing, along with the practice of keeping them. An interdisciplinary approach was taken in order to determine the social factors behind the decrease in stingless beekeeping and the ecological driving forces behind their disappearance from the wild. Social research methods included participant observation with stingless beekeepers, Apis beekeepers, and marketing intermediaries. Ecological research methods included point observations of commonly known melliferous and polliniferous plants along transects in three communities with different degrees of human induced ecosystem disturbance. The stingless bee species most important to the Maya, Melipona beecheii, has become extremely rare, and this has caused a breakdown of stingless beekeeping tradition, compounded with the pressure of the market economy, which fuels Apis beekeeping and has lessened the influence of traditional practices. The community with the heaviest amount of human induced ecosystem disturbance also had the lowest degree of bee diversity, while the area with the most intact ecosystem had the highest diversity of stingless bees, though Apis mellifera was still the dominant species. Aggressive competitive behavior involving physical attacks by Apis mellifera against stingless bees was observed on several occasions, and this is a new observation previously unreported by science. Human induced disturbance of the ecosystem and competition with the Africanized honey bee are affecting the diversity and abundance of various bee species.

A water quality model was developed to analyze the impact of hydrological events on mercury contamination of the Upper East Fork Poplar Creek, Tennessee. The model simulates surface and subsurface hydrology and transport (MIKE SHE and MIKE 11) and it is coupled with the reactive transport of sediments and mercury (ECOLAB). The model was used to simulate the distribution of mercury contamination in the water and sediments as a function of daily hydrological events. Results from the model show a high correlation between suspended solids and mercury in the water due to the affinity of mercury with suspended organics. The governing parameters for the distribution of total suspended solids and mercury contamination were the critical velocity of the stream for particle resuspension, the rates of resuspension and production of particles, settling velocity, soil-water partition coefficient, and desorption rate of mercury in the water. Flow and load duration curves at the watershed exit were used to calibrate the model and to determine the impact of hydrological events on the total maximum daily load at Station 17. The results confirmed the strong link between hydrology and mercury transport.

The purpose of this study was to determine the effectiveness of implementing Transportation Demand Management (TDM) initiatives with the business community by the South Florida Commuter Assistance Program (CAP). To determine this effectiveness, the south Florida CAP was compared with the two other CAPs operating in the state, by analyzing independent evaluations of the program, and by conducting eight individual company case studies. Independent evaluations of the south Florida CAP for the years 1997 - 2000 were analyzed and found to have increasing trends in the number of companies adopting TDM initiatives. In addition, each case was selected from the numerous companies participating with the south Florida CAP. It was determined that companies with support from upper management adopted TDM initiatives more readily. The findings demonstrated that the south Florida CAPs initiatives have been successful in working with the business community to adopt TDM initiatives. In its conclusions, the study offers further suggestions on what actions should be taken in the future to implement TDM initiatives.