The Perspectives/Visions/Actions framework is designed to facilitate deeper understanding of issues and broader inclusion of publics in landscape decision-making conversations. A parallel analysis of landscape and policy theory was used to constructed the framework. Common terminology and visual expression of spatial/temporal aspects of landscape are viewed through the interactive segments of Perspectives, Visions, and Actions. Perspectives described through landscape/human relationships and intuitive images of landscape provide insight into various viewpoints. Visions, visual landscape features described in landscape ecology terminology, provide a base for development of potential scenarios. Actions, Tools and Rules, relate viewpoints and scenarios to a range of choices for implementing change. Document content analysis, open-ended interviews, and systematic establishment of a transect baseline from aerial photographs were used to historically analyze three shoreline landscapes (Indiana Dunes National Lakeshore, Cape Cod and Point Reyes National Seashores) through framework language and schematic. Landscape information, viewpoints, and choices within the case study landscapes were uniquely illustrated. Perspectives groupings of intuitive images indicated ovelapping viewpoints and set an inclusive base for landscape information types. Visions landscape ecology language used both to construct the schematic and to translate information into comron expressions provided a base for issue discussion. Actions tools and rules data provided examples of implementation choices which related to the Perspectives and Visions.

Prepared by the Arid Lands Information Center, Office of Arid Lands Studies, University of Arizona ; Sandra J. Turner, compiler.

The goal of this dissertation was to develop application of ultrasonography as a decision-making tool in genetic improvement programs for channel catfish Ictalurus punctatus. A literature review on the use of ultrasonography in fish reproduction generated a comprehensive reference data set intended to benefit existing and potential users. It exposed the need for reporting of instrument control settings and standardization of fish handling and imaging procedures. These issues were addressed from the onset of this work by assessing more than 6,300 channel catfish ovaries by use of initial fish handling and imaging procedures developed (2004-2005) at the Louisiana State University Agricultural Center Aquaculture Research Station. The development of a standardized and systematic approach to interpretation of ultrasound images emphasized the interplay of technical and biological aspects of ultrasonography assessments. This showed the importance of the control settings and identified disruptive ultrasound artifacts to avoid for observation of the ovary and oocytes. A preliminary ultrasound imaging classification index for assessing ovarian development during the annual reproductive cycle was developed, used and evaluated. This led to the creation of seven well-defined, standardized ultrasound imaging classifications of channel catfish ovarian development based on the annual cycle. Histology of each ultrasound image in the classification index was included as a Reference Guide to provide insight into the processes observed during ultrasonography. Finally, the ultrasound imaging classification index was used for identification and selection of females for hormone-induced spawning in commercial hatchery production of F1 hybrids (channel catfish female x blue catfish male I. furcatus). In sum, this dissertation provides a systematic method of ultrasound imaging assessment of channel catfish ovarian development enabling progress towards standardization in the use of ultrasonography in fish reproduction.

Algal production is often the limiting factor in large-scale oyster hatcheries, and constant, reliable production is required to grow enough algae to support all oyster larvae and broodstock grown and conditioned in a hatchery. The algal rooms in the Michael C. Voisin Oyster Hatchery at Grand Isle, LA are temperature-controlled to maintain consistent temperature, but this hatchery is also unique in its ability to recycle natural seawater pumped from the northern Gulf of Mexico. Effects of recycling seawater on algal production in an oyster hatchery, however, are undocumented. In this study, Tisochrysis lutea, Chaetoceros calcitrans and C. muelleri were grown in different water sources to determine if productivity would be affected by water source. Algae were grown in ambient filtered seawater, recycled filtered seawater, and artificial seawater for a period of 10 days. To evaluate algal production, cell concentrations were measured every other day and dry biomass and growth rate were calculated. Water chemistry (nitrate, phosphate, and silicate concentrations) was measured initially and at ten days. Dry weights and growth were significantly different between species (p=0.0475, p<0.0001), but not water sources. C. muelleri grew the greatest in biomass and the slowest growth rate , followed by C. calcitrans, and T. lutea. Nitrate and phosphates had no significant effects on growth between species, although silicate content was significantly higher in T. lutea. Overall there were no statistically significant effects for the interaction of the three water sources on the growth of these algal species over time (p=0.2882). Although there were no significant differences, algae grown in ambient bay water grew denser and greater biomass than those in recycled bay water or artificial seawater.

The eastern oyster (Crassostrea virginica) and the reefs they create are highly valued for the ecosystem services they provide to coastal estuaries. Recently, their capacity to contribute to nutrient mitigation has spurred interest as researchers have identified 3 mechanisms directly or indirectly associated with oyster reef habitat. This study measured bioassimilation, long-term nutrient burial, and oyster-mediated denitrification in shallow-water (< 1 m water depth) and deep-water (> 1 m water depth) oyster reefs located in two southern Louisiana estuaries. Carbon and nitrogen assimilated into shell and tissue of small (< 75 mm) and large (> 75 mm) oysters was within the range of previous studies but was found to be less influenced by reef type, and more dependent on location specific factors and reproductive status. Post-spawning oysters were found to have higher percent nitrogen content in tissue compared to pre-spawning populations, likely a result of the loss of gametes and increase in feeding related activities during the post-spawn season. Carbon and nitrogen burial rates at oyster reefs ranged from 23.02-57.69 g m-2 yr-1 and 1.09-4.49 g m-2 yr-1 respectively and did not exceed that of other habitat types in Louisiana. However, they were considered to be an important source of nutrient mitigation in these estuaries. Shallow-water reefs buried significantly more nitrogen and carbon, which may be attributed to their proximity to the marsh edge and thus greater influx of detrital material. Closed-system ex-situ incubations revealed some of the highest ever recorded sediment denitrification rates at oyster reefs in the United States (> 1000 µmol m-2 hr-1). However, these values were within the range of those documented in Louisiana coastal systems, and similar to those recorded in nearby reference sediments. Variation in denitrification was found to correspond to site and season, rather than the influence of oyster reef habitat. Because the estuaries in this study are a matrix of reefs and soft bottom sediments, oysters may influence nutrient mitigation outside the boundaries of their active reefs. Thus, bioassimilation, burial, and denitrification may not be localized, but instead may resonate across larger areas as determined by historical reef acreage and hydrodynamics. These are among the first estimates for nutrient mitigation at oyster reefs in Louisiana, and indicate the potential of this ecosystem service in our region. Future research should consider site-specific conditions such as nutrient loading rates, oyster density, and active harvest to accurately quantify this ecosystem service across the coastal region of the state.

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Fisheries are among the most complex and tightly coupled social-ecological systems. This thesis develops new perspectives on the spatial features of fisheries, and on common pool resources in general. The central model of the work is the Distributed Commons, a commons spread across space with local and cross-boundary interactions. The model is founded in evidence from historical analysis and complexity theory, and offers insights for management and broader sustainable development policy. The second part of the thesis uses empirical analysis, applying Bayesian and econometric techniques, to study the spatial features exposed by the model. Finally, a computational model is calibrated for exploring the consequences of this theory through experiments. The implications of the Distributed Commons model are relevant to many areas of sustainable development, including atmospheric pollution, environmental degradation, and the use of ecosystem resources.

No description available.

No description available.

No description available.