The primary aim of the research conducted for this thesis was to develop a predictive model of information systems success for a publicly-available, web-based application that provides information to users on both the value of carbon credits that result from sequestration of carbon in a forest as well as potential earnings from supply of saleable timber. The application, also developed as part of this research, is called the CO2 Calculator. In addition attitudes of respondents to climate change and carbon sequestration were also gauged to ascertain their knowledge of key environmental issues relevant to the system.The model used as the foundation for the research is the DeLone and McLean (1992, 2002, 2003) model of information systems success. This model was adapted to measure information systems success for the CO2 Calculator which is a publicly available, web-based application rather than a proprietary, task-specific, organizationally focused application as measured in the prior research.Data was collected via a survey dispatched by email to users who accessed the CO2 Calculator. The survey instrument used builds on the existing work of Torkzadeh and Doll (1988, 1999), Seddon and Kiew (1994) and Torkzadeh et al. (2005). All of these researchers used variations of the End User Survey (EUS) to collect data on end users’ perceptions of the success of various applications, all of which were internal, organisationally-focussed, task specific, proprietary systems. This meant the survey items used for the current research were adapted to measure users’ attitudes to a publicly-available, web-based application that had no task-specific roles in an organisation.Analysis of the data proceeded in two distinct phases. The first phase was the examination and presentation of descriptive information about the demographic characteristics of the sample and the users’ attitudes to climate change, carbon sequestration and the overall success of the CO2 Calculator. The descriptive data indicated the respondents are a technologically literate group who have concerns related to environmental management and the use of land for sustainable practices. It also showed that the users were extremely satisfied with the CO2 Calculator.In the second phase Exploratory Factor Analysis (EFA) was used to examine the constructs underlying the data and Structural Equation Modelling (SEM) was used to examine the relationships among the constructs. Both the EFA and SEM resulted in structures and relationships that differed from the hypothesised outcomes and revealed a set of constructs and relationships that were clearly associated with the success of a publicly-available, web based application with different theoretical associations than those found by previous researchers examining organisationally-focussed, proprietary applications.Regression analyses were also conducted to check the relationships among constructs that were omitted from the final structural model, but were on the hypothesised model. Support for their inclusion in further studies was found as the analysis identified that the scales used to measure these constructs were significant predictors of the outcome variables although not when networked with those constructs that were on the final measurement model.Notwithstanding the limitations of the research, it has resulted in the identification of a predictive model of information success for web-based, publicly available, nonorganisationally focused systems.

The primary aim of the research conducted for this thesis was to develop a predictive model of information systems success for a publicly-available, web-based application that provides information to users on both the value of carbon credits that result from sequestration of carbon in a forest as well as potential earnings from supply of saleable timber. The application, also developed as part of this research, is called the CO2 Calculator. In addition attitudes of respondents to climate change and carbon sequestration were also gauged to ascertain their knowledge of key environmental issues relevant to the system.The model used as the foundation for the research is the DeLone and McLean (1992, 2002, 2003) model of information systems success. This model was adapted to measure information systems success for the CO2 Calculator which is a publicly available, web-based application rather than a proprietary, task-specific, organizationally focused application as measured in the prior research.Data was collected via a survey dispatched by email to users who accessed the CO2 Calculator. The survey instrument used builds on the existing work of Torkzadeh and Doll (1988, 1999), Seddon and Kiew (1994) and Torkzadeh et al. (2005). All of these researchers used variations of the End User Survey (EUS) to collect data on end users’ perceptions of the success of various applications, all of which were internal, organisationally-focussed, task specific, proprietary systems. This meant the survey items used for the current research were adapted to measure users’ attitudes to a publicly-available, web-based application that had no task-specific roles in an organisation.Analysis of the data proceeded in two distinct phases. The first phase was the examination and presentation of descriptive information about the demographic characteristics of the sample and the users’ attitudes to climate change, carbon sequestration and the overall success of the CO2 Calculator. The descriptive data indicated the respondents are a technologically literate group who have concerns related to environmental management and the use of land for sustainable practices. It also showed that the users were extremely satisfied with the CO2 Calculator.In the second phase Exploratory Factor Analysis (EFA) was used to examine the constructs underlying the data and Structural Equation Modelling (SEM) was used to examine the relationships among the constructs. Both the EFA and SEM resulted in structures and relationships that differed from the hypothesised outcomes and revealed a set of constructs and relationships that were clearly associated with the success of a publicly-available, web based application with different theoretical associations than those found by previous researchers examining organisationally-focussed, proprietary applications.Regression analyses were also conducted to check the relationships among constructs that were omitted from the final structural model, but were on the hypothesised model. Support for their inclusion in further studies was found as the analysis identified that the scales used to measure these constructs were significant predictors of the outcome variables although not when networked with those constructs that were on the final measurement model.Notwithstanding the limitations of the research, it has resulted in the identification of a predictive model of information success for web-based, publicly available, nonorganisationally focused systems.

Tree management practices in the tropical dry forest region of Nicaragua were examined to determine opportunities and factors influencing tree-planting initiatives and forest recovery within the agricultural matrix. A 217.11 ha tree inventory and 44 social surveys were conducted in three rural communities. The inventory found 88 species, 66.68% were native, and 70 valued for multiple uses. Farmers’ reasons for maintaining trees varied, emphasizing live fencing, wood, and fruit. The landscape also contains a tree plantation and a riparian forest, and the origins and management of these tree cover components of the landscape are also considered. Tree planting interventions should supplement extant stakeholder motivation with technical training and basic materials only as explicitly requested by participants, rather than imposing costly or inappropriate project preferences. Initiatives should also focus on smallholders and on multi-use native species suggested by stakeholders in order to maximize the economic, social and environmental benefits provided.

No description available.

Anthropogenic stressors are increasingly changing conditions in coastal areas and impacting important habitats. But, when multiple stressors act simultaneously, their effects on ecosystems become more difficult to predict. In Chesapeake Bay, USA, predictions suggest that anthropogenic stressors from climate change, such as warming temperatures, may increase the frequency and severity of storm events, leading to increased freshwater, nutrient, and sediment inputs. Coastal development, another source of anthropogenic stressors, continues to increase with growing coastal populations, and may lead to altered sediment characteristics, habitat fragmentation, altered food webs, and loss of vegetated habitats. Community processes may interact with stressors, for example, immigration of propagules between habitat patches may alter diversity, and modify community response to stressors. Changes in biodiversity might alter ecosystem functioning and services, but diverse ecosystems may be more stable especially in the face of multiple stressors. Many habitats are vulnerable to anthropogenic stressors, including seagrass systems, which provide many valuable ecosystem services. Understanding how multiple stressors and community processes interact now is key to maintaining ecosystem services in the future. Using a model seagrass (Zostera marina) system, I tested the effects of multiple stressors and their interactions with crustacean grazer immigration and diversity on ecosystem properties in a series of fully-factorial mesocosm experiments. I found that despite grazer species having varied responses to individual stressors, grazing pressure was largely maintained in spite of multiple stressors. More diverse grazer assemblages generally stabilized epiphytic algal biomass in the face of stressors, thereby increasing the resistance stability of this important component of the fouling community. Immigration of crustacean grazers did not interact significantly with stressors, and had little effect overall except to increase grazer biomass. Stressors generally reduced primary producer biomass, although in some cases they favored epiphytic algae. Generally, I did not find interactions among stressors and grazer immigration or diversity, even though diverse grazer assemblages stabilized epiphytic algal biomass. to assess potential impacts of coastal development, I surveyed twenty seagrass beds in lower Chesapeake Bay, VA and assessed local shoreline development effects on adjacent seagrass beds. I sampled primary producers, consumers, water quality, and sediment characteristics in seagrass beds, and characterized development along the adjacent shoreline. I found that development significantly affected sediment characteristics, while epifaunal and epiphytic algal biomass was significantly higher on the Western versus the Eastern side of the bay. Grazer and predator biomass did not differ with either development or bay region. Thus, in seagrass communities, various factors appear to drive sediment and biological community properties on different spatial scales. This may be an important consideration for management, because efforts that incorporate spatial scales of ecosystem processes will likely have more impact. Overall, these results suggest that stressor impacts in seagrass ecosystems generally do not interact but are sometimes context specific, while grazer diversity may have a limited but potentially important role in buffering certain ecosystem properties again stressors. Different factors appear to influence ecosystem properties at various spatial scales, an important consideration for predicting future impacts of multiple anthropogenic stressors in submerged vegetated systems.

No description available.

Seeding deteriorated range lands efficiently and economically has become one of the most promising means of improving the agricultural economy of the western range states. By providing the most rapid means of increasing the quantity and improving the quality of forage for livestock, and aiding in the prevention of soil erosion, artificial seeding contributes directly to the stability of agriculture.

The particular purpose of this study was to determine the effects of large-scale sagebrush reseeding projects on sage grouse populations and whether such effects were partly or entirely beneficial, neutral, or detrimental to the survival of such populations. During two seasons of field work, the studies initiated on a short-time basis had the following specific objectives: To compare the utilization by sage grouse of reseeded and non-reseeded lands for the seasonal activities of mating, nesting, raising a brood, fall coveying, and wintering. To compare the utilization by sage grouse of reseeded and non-reseeded lands for daily activities of feeding, watering, resting, hiding, and roosting. To determine fall and winter movements of the grouse in relation to reseeded lands. To determine the food and cover available to grouse on randomly selected sample plots To arrive at an index to food preferences through comparison of stomach analysis and food availability studies. To determine the effect of livestock grazing of reseeded lands on sage grouse. To determine the effect of plant succession on availability of food and cover within reseeded lands.

Pentachlorophenol (PCP) is one of the prominent environmental pollutant that has penetrated into food chain and is present in humans. Health concerns have been raised since daily intake of PCP by the US population is estimated to be 16-19 µg. PCP facilitates dissipation of electrochemical potential gradients of hydrogen ions across energy transducing membranes, which are the energy sources for the conversion of adenosine diphosphate into adenosine triphosphate. Closely linked to these dissipative effects is the development of electrical conductivity in lipid membranes, induced by the presence of PCP. Three modes of PCP - induced membrane electrical conductivity were theoretically analyzed and experimentally verifiable formulations of each models were developed. Experimental studies using the charge - pulse method involved characterization of the time dependent transmembrane voltage over a wide pH range, from 1.8 to 9.5, for 30 µM concentrations of PCP. Lipid membranes were prepared from dioleoyl phosphatidylcholine. It was shown that three PCP molecular species were determining the transmembrane transfer of hydrogen ions: electrically neutral PCP molecules (HA), negatively charged pentachlorophenolate ions (A⁻) and negatively charged heterodimers (AHA⁻). It was found that at pH>9 the membrane electrical conductivity was determined by the transmembrane movement of A⁻ ions, whenever pHAHA⁻ species. Two new membrane surface reactions were proposed as supplementary mechanisms for the generation of AHA⁻ in addition to the formation of AHA⁻ by the recombination of HA and A⁻, HA + A⁻→ AHA⁻. These new reactions are, (i) 2HA → H⁺ + AHA⁻, and (ii) H20 + 2A⁻ → OH' + AHA⁻. Reaction (i) provides formation of membrane permeable heterodimers AHA⁻ at pH < < 5.5 and reaction (ii) at pH> > 5.5. The maximum surface density of AHA" heterodimers was 0.09 pmol/cm² • The rate constant of formation of AHA' by recombination, HA + A⁻ → AHA' was estimated to be k[subscript f] = 2.6xl0⁹ cm² mol⁻¹ s⁻¹ and the dissociation rate constant for AHA⁻ Further, it was possible to determine the rate constants of transmembrane translocation for A' and AHA⁻ ions to be k[subscript a] = 6.6x10⁻⁵ s⁻¹ and k[subscript aha] = 1200 S⁻¹, respectively.

Participatory, collaborative modeling processes represent a unique decision-making technique within natural resources management that allows for the combination of stakeholder involvement with the analytical and predictive power of scientific models. The continued use of participatory modeling within decision-making processes depends in part upon the willingness of stakeholders to participate. Continued participation of stakeholders is key to the persistence and overall success of these processes, and yet limited information exists concerning the impacts of these processes on participants. The consideration of human dimensions advances our understanding of the design and function of participatory modeling processes, including their ability to create consensus outcomes, their capacity to integrate natural and social sciences, and their capability to advance sustainable natural resources policy and management. Within this thesis, I analyzed stakeholders’ advice and communication social networks and their attitudes towards scientific models to better understand the impact of these participatory modeling processes on participants. I found that the development of group cohesion was more heterogeneous than previously thought. While there was a significant increase in advice ties between OysterFutures members, silos of advice within stakeholder groups remained. There was also a high level of between-stakeholder group advice ties that existed prior to the OysterFutures process. This history between stakeholders and stakeholder groups is also thought to have impacted the development of advice ties. Lastly, the transition of the advice network structure over time supports arguments in the literature that suggest that different network structures are necessary at certain time points during participatory processes. Stakeholder group silos also persisted within the communication network. These silos are thought to have helped stakeholder groups develop their own attitude towards scientific models based on their unique “way of knowing”. As a result, attitudes towards models were significantly different between stakeholder groups. This strength of stakeholder group impact on attitudes likely limited overall changes in attitudes towards models over the course of OysterFutures. The importance of considering social network structure of participatory modeling processes was demonstrated through results that certain brokering network positions significantly impacted attitudes towards models. Methods to facilitate more between group communications during participatory modeling processes could help mitigate the strong impact of stakeholder group membership on attitudes. Overall, results for attitudes towards models support the idea that models are acting as “boundary objects” that help facilitate discussion during these processes.