Browsing by Subject "conservation"
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Item A mammoth of a project: the conservation of a columbian mammoth(2009-05-15) Daniel, Shanna LaReaThis thesis concentrates on discovering the best consolidant or consolidants for stabilizing a Columbian mammoth?s sub-fossilized mandibles, a distal femur, an ulna, a radius, and a tooth. It was recovered from a wet, sandy gravel pit owned by the Vernor Family located in Clute, Texas. Based on thermoluminescence dating, the mammoth dates to around 66,000 years ago. The bones are fragile and unstable. They retain a minute amount of organic material (collagen) and hydroxyapatite, but not enough to retain any structural support. Experiments and analyses were conducted on various bone samples to compare each of the following consolidants? properties. The consolidants examined were silicone oil, polyvinyl acetate (PVA) with viscosity of 25, Acryloid B-72, Butvar 98, Starbond EM-02, methyltrimethoxysilane (MTMS), Paleo-bond, and Rhoplex (Primal) WS24. Stability, strength, and appearance were evaluated by measurable observations. The Scanning Electron Microscope (SEM) and the Environmental Scanning Electron Microscope (ESEM) at the Microscopy and Imaging Center at Texas A&M University were used to map penetration of these consolidants. SEM was utilized for both imaging and energy-dispersive x-ray spectroscopy (EDS) to examine the presence and absence of certain elements. ESEM was used to view consolidants at the microscopic level to further examine the bonding between the consolidant and the bone?s cellular structure. By examining and testing all the consolidants, methyltrimethoxysilane (MTMS) was chosen to stabilize the ulna, radius, left and right mandibles, distal femur, and tooth. This research opened new avenues to different methods in preserving sub-fossilized bone and broadens our understanding of bone conservation.Item A Necessary Duty, A Hideous Fault: Digital Technology and the Ethics of Archaeological Conservation(2010-07-14) Smith, Megan H.Archaeological conservation is the process by which conservators prevent deterioration of archaeological remains and provide insight into the nature of recovered material. This thesis examines the effect of digital technology upon the ethics of the conservation profession and upon the attitude of the lay-public towards archaeology. The ethical issues raised by the use of digital technology are discussed, particularly the ways in which these issues differ from those raised by traditional conservation methods. Technological advancements, particularly those occurring in the 20th century, changed the way artifacts are conserved and studied. Conservation arose out of a craft-restoration tradition and evolved into a profession which, in addition to necessary artistic and aesthetic considerations, uses a demonstrable scientific method in order to preserve artifacts. The creation of guidelines for practice and various codes of ethics is the turning point in this evolution, marking the point after which conservation became a scientific profession. Advances in computer technology have permitted the widespread use of devices such as 3-D scanners, digital CT scanners, and digital cameras in the conservation of archaeological artifacts. All of these pieces of equipment produced digital files which must be stored. Currently, the pace of technological change renders most data inaccessible within ten years, and data conservation problems such as storage, access, and file format have not been adequately addressed by the professional conservation community. There is a distinct lack of formal ethical guidelines concerning these issues; this thesis concludes that there is an extreme need for measured consideration before digital methods are used in archaeological conservation. The creation of high-fidelity replicas presents a problem for the museum audience. The public connects with artifacts on an emotional level which is altered when a replica is displayed instead of an original. Digital reconstructions abound in popular culture, heavily influencing public opinion, and often resulting in widespread misperception of the information which can be extracted from archaeological evidence. As a result, conservators of the future must be cautious when creating digital artifacts, and must be meticulously careful to make the nature of digital reconstruction clear to the audience, in order to avoid spreading misinformation.Item Abundance and distribution trends of the West Indian manatee in the coastal zone of Belize: implications for conservation.(Texas A&M University, 2004-09-30) Auil, Nicole EricaThe coastal zone of Belize is home to the largest recorded number of the threatened Antillean manatee (Trichechus manatus manatus) within the species' Caribbean range. The objectives of my study were: (1) to determine long-term trends in aerial survey counts and indices of the manatee population in the coastal zone of Belize; and (2) to examine the seasonal change in manatee distribution among habitats in the coastal zone. Standardized extended-area aerial surveys were conducted along the entire coastline of Belize in the dry and wet seasons of 1997, and 1999 - 2002. Manatees were counted in five habitat categories: cay, coast, estuary, lagoon, and river. Total sightings per survey ranged from 90 to 338; the greatest number was counted in the 2002 wet season. Calf percentage ranged from 5 to 13. A slight negative trend in total counts was significant for dry-season, not wet-season surveys, indicating an interactive effect of season and year. Based on analysis of variance, the Abundance Index (transformed manatee sightings per hour) did not differ significantly among years, although it varied significantly within year by season and habitat by season. In applying a spatial approach, the general survey route was buffered 1 km on both sides, and 1 km grids were overlaid and classified by habitat type. The presence or absence of each cell for each survey was used in likelihood ratio tests of the single and interactive effect of season and habitat. The Index for river habitat was higher in the dry season, while cay habitat was higher in the wet season. Overall, near-shore habitat (estuary, lagoon, and river) showed a higher Index than did the offshore habitat (cay and coast) although the total number of sightings was higher offshore. Considering the interactive effect of year, season, and habitat, long-term studies are needed, in both seasons, and among all habitats to account for variation. Continued broad-scale surveys, along with metapopulation analysis would fine-tune the understanding of specific sites, enhancing integrated coastal zone management for protected species and their habitat systems.Item Behavioral Patterns of Common Bottlenose Dolphins in Galveston, Texas and Protection Strategy Development(2014-04-19) Rivard, Alexandria ElizabethThe objective of this study is to establish a protection strategy for common bottlenose dolphins in the Galveston, Texas area based on quantifiable behavioral patterns. This area is subjected to regular vessel traffic entering the commercial ship channels. I used The Galveston-Port Bolivar ferry at the entrance of the ship channels as a platform for assessing variations in dolphin group behavior. Over six months, I conducted 1,412 hours of observation. Resting behavior occurred significantly more frequently than expected in Bolivar; traveling, more frequently in the passage; and foraging more frequently in Galveston (p < 0.01). Traveling dominated in open water (p < 0.01). Foraging was most prevalent in the morning and resting in the evening (p < 0.01). Group size deviated significantly across the assessed factors in a negative binomial hurdle model (p < 0.01). Calves were equally common in all three zones (p > 0.01), but more common in foraging groups and less common in resting groups (p < 0.01). Groups with calves were most frequently found at intermediate distances to shore (p < 0.01), and in the morning time (p < 0.01). Vessel activity was highest in Galveston and lowest in Bolivar, and decreased from the morning to afternoon to evening (p < 0.01) Next, existing regulation, management, and educational outreach strategies were evaluated to determine their effectiveness, appropriateness, and applicability to marine mammals in Galveston Bay. In many cases, these strategies were insufficient to meet the unique needs of the Galveston area. Federal law enforcement officials are often overtaxed and unable to enforce existing laws; I advise that the State of Texas pass a state law for marine mammal protection and issue a voluntary dolphin rest zone in Bolivar. Existing management strategies are better suited to large corporations, but participation may be beyond the means of smaller companies. I propose a local ?Responsible Marine Business? program be instituted in Galveston to promote conservation on a local scale. Public education is critical to any conservation effort; I recommend a multi-pronged outreach, including public workshops, school programs, and educational signage installation to promote bottlenose dolphin protection and encourage ecotourism.Item Conservation of Antillean manatees in the Drowned Cayes area of Belize(2009-05-15) Sullivan, Caryn SelfThe purpose of this study was to determine how manatees use Swallow Caye, Drowned Cayes, and Gallows Reef, three distinct habitat types within the Belize Barrier Reef lagoon system near Belize City. Data were collected using boat-based point scan methods with the assistance of volunteers. Presence/absence and photo ID methods ensured consistency of data collection despite a changing pool of volunteer researchers. Results confirmed the mangrove and seagrass ecosystem between the Belize Barrier Reef and Belize City as important manatee habitat. Inconsistent with the prevailing "seasonal distribution hypothesis" for manatees in Belize, the probability of encountering manatees at Swallow Caye and in the Drowned Cayes was equal between dry and wet seasons. However, manatees were only observed at Gallows Reef during the wet season. Swallow Caye had the highest probability of encountering manatees, confirming traditional knowledge held by local tour operators, which led to the establishment of Swallow Caye Wildlife Sanctuary in 2002. In contrast to previous studies, my data suggest that at least 44% of the manatee population carry scars from non-lethal boat strikes. The proportion of scarred animals did not vary as a function of habitat type, season, or year. The probability of encountering manatees did not change between years, despite an exponential increase in cruise ship tourism. Marine Protected Areas (MPAs) and wildlife protection laws indicate that Belize is working to meet obligations under international agreements. However, there is still cause for concern. Manatees do not remain inside designated refuge boundaries; governmental agencies depend on co-management agreements with local non-governmental organizations for enforcement of rules inside MPAs; regulations governing human behavior outside MPAs are lacking; funds for monitoring and evaluation of MPAs are lacking. Manatee conservation strategies should be integrated into a system of riverine, coastal, and marine protected areas supported by additional tactics such as required manatee training for boat captains, slow zones at hot spots outside MPAs, and continued educational outreach. With few modifications and increased enforcement and monitoring, the Belize model for manatee conservation could lead to a shared "triumph on the commons" for the manatees and the user groups that shared their habitat.Item Conservation of waterlogged linoleum(Texas A&M University, 2005-02-17) Coke, BobbyeJo EvonLinoleum has been around for over a hundred years. With its invention by Frederick Walton in the 1860?s a new means of durable floor covering was introduced to the world. This new invention was promoted as durable, hygienic, and easy to maintain. In agreement with the Lake Champlain Maritime Museum, a study was commissioned to seek the best means to conserve linoleum from a canal boat excavated in the summer of 2002 in Lake Champlain. The Sloop Island Canal Boat is part of an excavation project that is studying the ways of life on the lake. Conserving waterlogged linoleum is a new area of study in conservation, and there is very little information dealing with the topic. This study will provide a baseline for the conservation of linoleum.Item Conserving Waterlogged Rope: A Review of Traditional Methods and Experimental Research with Polyethylene Glycol(2010-01-16) McCaskill, Jennifer R.The excavation of Sieur de la Salle's ship, La Belle, yielded a large amount of waterlogged rope requiring conservation. A history of hemp and rope manufacture is reviewed to assist in the identification of the materials and rope-work recovered from the La Belle, as well as to assist in selecting an appropriate conservation treatment. A summary of several methods used to conserve cordage is presented. Time has shown that not all of these treatment methods have remained viable options, and that continued study and experimentation are needed so that the conservator has the tools to develop an appropriate conservation plan for each artifact. The majority of La Belle's cordage was conserved using the passivation polymers method developed by Dr. C. Wayne Smith and Dr. Donny L. Hamilton, both of Texas A&M University, in conjunction with Dow Corning Corporation, Midland, Michigan. An experiment applying knowledge gleaned from the passivation polymers process to polyethylene glycol (PEG) impregnation was conducted in an attempt to stabilize the PEG within the rope. The results were good; the rope retained some flexibility and appears stable with a slightly darker color than with silicone oil.Item Deficit Irrigation Programs for Water Conservation in the Management of Bermudagrass Fairways in Texas(2014-04-29) Hejl, Reagan WesleyGolf course water use in Texas has become increasingly regulated in the past decade due to persistent drought conditions, diminishing water supplies, and rapidly a growing population. Many golf courses have been faced with considerable cutbacks in irrigation allocations, but information is limited regarding critical levels needed for maintaining adequate turf quality, persistence, and recovery from divots and traffic. Furthermore, the effects of irrigation water quality on minimal irrigation requirements has not been fully resolved. A series of field and greenhouse studies were conducted over the course of two years in College Station, TX, to determine the effects of continuous reference evapotranspiration (ET_(o))- based deficit irrigation levels on quality of bermudagrass fairway turf. Turf quality evaluations from both seasons showed that in the absence of traffic, irrigation levels of 0.3 x ET_(o) were sufficient to maintain acceptable turfgrass quality during summer months (at a 3-day per week irrigation frequency). Canopy temperatures increased considerably as irrigation was reduced; with up to a 20? increase detected between irrigated and unirrigated plots. Upon resumption of full irrigation levels in September, unirrigated and deficit-irrigated plots quickly recovered to ~90% green cover within 8 weeks in year 1. However, unirrigated plots were much slower to recover in the second season, only reaching ~30% green cover by 8 weeks. The delayed ability of unirrigated plots to rebound following successive years without irrigation suggests a cumulative effect of drought stress on bermudagrass health and vigor. Traffic treatments delayed recovery across all irrigation levels. Greenhouse investigations into irrigation water quality (reverse osmosis (RO), saline, and sodic) and plant growth regulator trinexapac-ethyl (TE) effects on bermudagrass evapotranspiraton and tolerance to deficit irrigation were also undertaken. Irrigation water quality failed to significantly influence minimal irrigation requirements, but turf irrigated with sodic irrigation did exhibit considerably higher evapotranspiration (ET) rates relative to those receiving saline or RO irrigation. TE improved bermudagrass quality and delayed leaf firing under the soil moisture stress from deficit irrigation. The findings from this research provide timely and practical information for turf managers who must increasingly utilize ET-based irrigation scheduling and/or low-quality water sources in the management of golf course turfgrass systems.Item Development of a method for recording energy costs and uses during the construction process(2009-05-15) Arnold, Althea GayleRising energy costs should be a concern to contractors, designers, and owners. It is difficult to make a quantity takeoff for energy usage because these costs are imbedded in the materials, equipment, or overhead costs. This research examines energy consumption during the construction process, sets forth methods for recording this energy consumption and establishes a program for the recording and analysis of this data. An energy study of electricity, gasoline, and diesel consumption was made for the construction of three buildings to determine what data was available. After available data was evaluated, and the Energy Data Analysis program developed, three other construction sites were visited to determine how readily energy data can be recorded using the program. Four construction energy phases were identified from this research. The four phases are: 1) site clearing and preparation, 2) building structure, 3) interior finishes, and 4) commissioning. The main type of energy consumption during Phase 1 is diesel fuel for earth moving equipment. The energy uses for Phases 2 and 3 varied considerably among the projects studied and were difficult to quantify. However, the energy use during these phases was low compared to other phases and for many projects may not be economical to evaluate. During Phase 4, electrical energy demand was high due to Heating, Ventilation and Air Conditioning (HVAC) commissioning requirements and power up of all electrical power uses including lighting. These few construction projects are not enough to make definitive conclusions about what percentage of the total project cost is spent on energy. This research found that construction energy costs vary during different phases of the building process and can be a significant part of that phase (as high as 5.7% of the cost). The Visual Basic program developed during this research will facilitate future energy studies on construction sites. When the program is applied to a project, it identifies and quantifies the energy use, and makes predictions as to which project tasks warrant further energy studies.Item Ecological Consequences of Landscape Fragmentation on the Lizard Community in the Mescalero-Monahans Shinnery Sands(2012-10-29) Leavitt, Daniel 1979-Landscape fragmentation poses a major threat to biodiversity world-wide. The goal of my dissertation research was to determine the effects of landscape fragmentation on a lizard community in the Mescalero-Monahans shinnery sands, New Mexico and the extent to which conservation efforts might protect biodiversity in this ecosystem. My research relied heavily on data collected from a large-scale spatially-replicated comparative study. The purpose of this study was to evaluate the impacts of landscape fragmentation as a result of oil and gas development on the dunes sagebrush lizard (Sceloporus arenicolus). Results from analysis of lizard community structure indicate that fragmented sites are less diverse than non-fragmented sites. In particular, two species are found in lower density and occupancy in the fragmented locations (Holbrookia maculata and Sceloporus arenicolus). Analysis of landscape configuration at the scale of a trapping grid indicated that sand dune blowout shape and size differed between fragmented and non-fragmented locations. Differences in landscape pattern were associated with reduced lizard diversity. Because of this association between lower diversity and altered landscape pattern, extensive alterations to landscape pattern may cause disassembly at the ecosystem level. The maintenance of existing landscape pattern may be important to the maintenance of diversity in this ecosystem. Evaluations of habitat use patterns of the lizards in this community demonstrate that a few species have narrow preferences for certain habitats. In particular, H. maculata, Phrynosoma cornutum, and S. arenicolus all demonstrated narrow habitat use patterns. Effect size of fragmentation for each species indicated that the same three species showed a large effect when comparing their average abundances between fragmented and non-fragmented locations. Thus species that are most likely to benefit or be harmed by landscape fragmentation are those with the most specific habitat requirements. Umbrella species represent one of many approaches to conservation using surrogate species. I used data on ants, beetles, small mammals, lizards, and endemic species to test the use of the dunes sagebrush lizard (Sceloporus arenicolus) as an umbrella for endemism and biodiversity of the Mescalero-Monahans shinnery sands ecosystem. I applied a comparative approach at three spatial scales to examine how conservation practices at different scales may affect biodiversity and endemism in this ecosystem. At the largest scale, the frequency of occurrence for endemic species increased though no other patterns emerged because S. arenicolus was present at all sites and there were no relationships between relative abundances of S. arenicolus and the other taxonomic groups. At the smallest scale, both beetle species richness, diversity, and endemic species richness were higher in the presence of S. arenicolus. To protect biodiversity in this ecosystem, conservation efforts should focus on protection at the scale of the species distribution rather than on the small-scale placement of individual well pads.Item Ecology of Wintering Black-capped Vireos in Mexico(2013-11-06) Powell, Robert AndrewThe black-capped vireo (Vireo atricapilla) is an endangered Neotropical migratory songbird that has received considerable attention in its breeding range, but relatively little attention in its winter range in Mexico. To address information needs regarding winter ecology of the black-capped vireo, I conducted research in Mexico focused on investigations of the winter distribution, habitat use, and migratory linkages between breeding and wintering sites. Over 3 winter periods in 2002?2004, I identified and described the geographic distribution for the black-capped vireo at study sites across 8 states in western Mexico and determined if differential migration occurs among different classes of individuals. I documented winter occupancy in the 5 most northern Mexican states surveyed (Sinaloa, Durango, Nayarit, Jalisco, and Colima), and identified a strong association between sex/age class and winter latitude with adult males occupying habitat at more northern latitudes relative to females and juveniles. During two winters in 2003-2004, I conducted field research at study sites in Mexico to evaluate patterns of winter habitat use by black-capped vireos and determine which habitat characteristics may influence vireo use of winter patches. Winter habitat use by black-capped vireos was best predicted by increasing values of slope and foliage cover, and by decreasing values of canopy cover and tree diameter. Vireo use plots characterized as thorn forest had greater foliage density, greater shrub density, less canopy cover, and smaller tree diameter than plots classified as tropical deciduous or semi-deciduous forest, suggesting that thorn forests may be most suitable for vireo occupancy during the winter months. I also used stable carbon, hydrogen, and nitrogen isotopes in black-capped vireo feathers obtained across 3 states in the breeding range and 8 states in the wintering range to determine if vireo feathers collected on the wintering grounds could be used to assess breeding origins and to determine if a relationship exists between breeding and wintering latitudes such as chain or leapfrog migration. Feathers collected at both breeding and wintering sites displayed considerable variability in isotopic composition for all 3 isotopes analyzed, and thus did not provide sufficient information to establish migratory linkages between breeding and wintering sites.Item Empowering All Who Dwell Here: Natural Resource Management and Public Participation(2014-08-01) Bernacchi, Leigh AlexisI studied the potential for community-based planning in the winter habitat of the federally-endangered whooping crane (Grus americana) to better understand the relationships, barriers and opportunities to conservation and public participation. Rooted in the literature of public participation in natural resource management, I describe my project within this larger discourse. I seek to address the issue of local public resource management and the ways in which it is or is not represented in public processes. I submit constructive ameliorations for improved democratic engagement, resource and wildlife conservation. My methods are qualitative: 35 local and regional individuals interested in crane conservation were interviewed, transcribed, and coded in NVivo Qualitative Analysis software from QSR International to conduct a content analysis. I employed theoretical and pragmatic constructions to provide constraints and perspectives on the same dataset. I apply a ritual communication perspective to the communication among birdwatchers and with birds. Though a wide-ranging topic, I describe the key aspects of birding, and how competition and cooperation are the two sides of birding?s social relations. I propose that wildlife managers could pay attention to these relationships to better represent interests in birds in management. I examine how wildlife managers are tasked with engaging the public for natural resource management and planning, and I propose that including a responsive public can improve the plan and conservation. I found that the public was amenable to working with wildlife managers due to whooping the crane?s iconic nature and economic value, and the public was responsive to agency intervention when they were dependent on their knowledge and standing for navigating the dynamic complexity of managing the species and ecosystem. By recognizing a responsive public, wildlife managers can expand public participation to include more public perspectives. From a public understanding of science perspective, I explore the dominant scientific narratives associated with whooping crane conservation. I examine these narratives for their ability to empower and to constrain public participation in various management schemes. I argue that production of a reductive scientific narrative reproduces an equally reductive public discourse that limits possibilities for public participation.Item Environmental governance and implications of small-scale logging: the case of the indigenous groups in the Ampiyacu Basin in the northeastern Peruvian Amazon(2009-08) De La Rosa Tincopa, Carolina; Young, Kenneth R.; Sletto, Bjørn; Doolittle, William Emery; Knapp, Gregory W.Small-scale logging by indigenous people in Amazonia remains little studied despite the importance of this activity to forest communities and its relevance to the implementation of conservation initiatives. Previous studies in the region have given an overview of small-scale logging and the role of local institutions in the management of timber resources. This study provides insight into the local institutions that govern the use of timber resources and the timber extraction practices of indigenous communities in Amazonia. Timber extraction was examined through a regional case study of indigenous people along the Ampiyacu River, an affluent of the Amazon near Iquitos, Peru. An analysis of the actors within and outside of the Ampiyacu Basin involved in timber harvest and the local institutions for regulating access to forest resources provides the context for examination of local arrangements in small-scale logging. Detailed information about local institutional arrangements was collected through a mixture of qualitative methods, including archival research, focus groups, structured interviews, and direct observation. An analysis of timber practices and the sustainability thereof in extraction areas for the 13 villages of the region allowed a characterization of small-scale logging practices and revealed the most relevant factors in timber extraction strategy and economics. Local arrangements were explained by policy, proximity to an urban market, and access to funding. Most loggers are poor, earning less than $ 496/year in cash, although income levels varied widely within type of funding. The higher income loggers are specialists who log more than the permissible quota and have greater access to funding. Timber was the central economic activity of all local residents. The implications of these findings are discussed for local arrangements and future research on small-scale logging by indigenous peoples of Amazonia.Item Factors Influencing the Adoption of Water Quality Best Management Practices by Texas Beef Cattle Producers(2014-05-28) Peterson, JenniferThe management of agricultural nonpoint source pollution is complex due to the diffuse nature of the various sources. As a result, rather than relying on direct regulation, natural resource agencies generally utilize a watershed approach to encourage the voluntary adoption of best management practices (BMPs) to improve water quality and control nonpoint source pollution originating from livestock, farm, and forestry operations as well as urban nonpoint sources. Policy tools used to encourage voluntary adoption include educational programming as well as technical and financial assistance opportunities. Despite the known water quality benefits of BMPs and the availability of policy tools to encourage adoption, some landowners and livestock producers choose not to adopt conservation practices. This study examined the current adoption behavior of Texas beef cattle producers and investigated how factors related to capacity, attitudes, environmental awareness, and farm characteristics influenced the adoption of BMPs known to reduce levels of bacteria, sediment, nutrients, and other contaminants in runoff. A statewide mail survey of beef cattle producers was conducted in the Fall of 2013. Univariate probit analysis was used to estimate the influence of 30 predictor variables on the probability of a beef cattle producer adopting 18 different water quality BMPs. Results from the analysis show producers are adopting and maintaining water quality BMPs despite a significant lack of knowledge concerning common water quality terms and the availability of financial assistance programs to aid in practice implementation. The most significant predictors of adoption among survey respondents included visits with Extension, prior participation in a government cost-share program, crop diversity, annual income, and percent income from the operation. The most significant factors reducing the probability of adoption among survey respondents included education, gender, visits with NRCS, membership in a livestock organization, and having a family member take over the operation. These results suggest the need to address information gaps among beef cattle producers as well as demonstrate a significant opportunity for the NRCS and Extension to forge a strategic long-term partnership to promote increased and sustained adoption of water quality BMPs.Item Food web architecture in natural and impounded rivers of the Upper Parana drainage basin, Brazil(Texas A&M University, 2007-04-25) Hoeinghaus, David JosephFreshwater ecosystems are some of the most threatened on the planet. Efforts to conserve, restore, or otherwise manage large rivers and the services they provide are hindered by limited understanding of the functional dynamics of these systems. This shortcoming is especially evident with regard to trophic structure and energy flow. In this study I use natural abundances of carbon and nitrogen isotopes to examine patterns of energy flow and food-chain length of large-river food webs characterized by different landscape-scale hydrologic features. Ten locations along an approximately 500 km stretch of the Upper Paran???? River Basin, Brazil, provided the setting for this work. Carbon derived from C3 plants and phytoplankton were the dominant energy sources across all webs, but relative contributions differed among landscape types (low-gradient river, high-gradient river, river stretches downstream of reservoirs, and reservoirs). Increases in food chain length corresponded with higher relative importance of phytoplankton derived carbon, likely due to size-structured effects of the phytoplankton-zooplankton-secondary consumer trophic link. River impoundment corresponded with decreased ecological and economic efficiency of fisheries production, an important ecosystem service provided by many tropical rivers.Item From Theory to Application: Extreme Fire, Resilience, Restoration, and Education in Social-Ecological Disciplines(2012-07-16) Twidwell, DiracConceptual and theoretical advancements have been developed in recent years to break down the assumptions and traditional boundaries that establish seemingly independent disciplines, and the research outlined in this dissertation aspires to build on these advancements to provide innovative solutions to a broad array of modern problems in social-ecological. I used a variety of techniques to address challenges ranging from disconnections between theory and application, perceived versus realized roles of prescribed fire in resprouting shrublands, and the need for broader participation in research as part of undergraduate education. The chapters in this dissertation serve as a case-study approach across multiple scientific disciplines that overcome the traditions and assumptions that conflict with our ability to develop innovative solutions to modern social-ecological problems. First, I bridge theoretical and applied concepts by showing how recent theoretical advancements in resilience can be integrated into a predictive framework for environmental managers. Second, experimental data from multiple experiments were collected in two ecological regions of Texas to assess the potential for using extreme fire, in isolation and in combination with herbicide, as a novel intervention approach in resprouting shrublands of the southern Great Plains. The findings from these experiments demonstrate the importance of moving past traditional assumptions of when prescribed fire should be applied to demonstrate new patterns of woody plant responses to the applications of ?more extreme? prescribed fires while not causing undesirable invasions by exotic grasses and exotic insects. Finally, I initiated a PhD instructed course on undergraduate research that sought to increase undergraduate participation while lowering the costs of conducting research. This chapter shows how traditional approaches of supporting undergraduate research are incapable of meeting the broader goals established by society and reveal a novel approach that can provide an additional pathway for supporting undergraduate student participation at large, research-based universities. Ultimately, this research suggests that our capacity to enhance services in social-ecological systems ultimately hinges upon the integration of theoretical and applied concepts that drive policy and governance and overcoming the assumptions and traditions that limit their integration.Item Granger Lake Sedimentation and Watershed Conservation Implementation Assessment(2012-02-14) McAlister, JasonSedimentation rates for many Texas reservoirs may be skewed by overstated estimates of design capacity and assumptions perpetuated through subsequent volumetric surveys. Multi-frequency reservoir surveys offer the means by which we may improve existing reservoir data and validate historic sedimentation rate estimates. To demonstrate application of this technology and value of its data derivatives, a multi-year, multi-frequency acoustic survey of Granger Lake, located in Williamson County, Texas was undertaken. Objectives of the study were to use hydro-acoustic survey techniques to verify assumptions of original reservoir capacity, examine the general accuracy of previously derived sedimentation rate, and document conservation implementation effectiveness. The intended benefit of these pre and post-watershed conservation implementation project surveys was to provide a temporal snapshot of sediment flux. Specifically, these data would be used as a tool to quantitatively estimate project success or non-success in annual sediment delivery reduction to the reservoir. During the course of the Granger Lake Watershed Implementation project, Granger Lake lost on average 343 acre feet of water storage annually to watershed sediment contribution. Sediment profiling results indicate pre-impoundment design estimates were overstated, thus skewing subsequent sediment deliver estimates. Since the mid-1990's, an accelerating sedimentation trend is apparent. Conservation implementation is not plainly responsible for the decrease in sediment delivery, and in fact may be undetectable for the foreseeable future. The study illustrates the value of examining previously established reservoir sedimentation estimates and assumptions of reservoir life based on design capacity estimates and routine volumetric surveys. Insights from this research highlight the importance of validating historic reservoir survey data and significance regarding its use in quantifying historic and future conservation effects, or other reservoir sustaining strategies.Item Mycorrhizal Associations, Life History, and Habitat Characteristics of the Endangered Terrestrial Orchid Spiranthes parksii Correll and Sympatric Congener Spiranthes cernua: Implications for Conservation(2013-12-10) Ariza, Martha CSpiranthes parksii Correll is a federally listed endangered terrestrial orchid endemic of Texas. The species exhibit a very limited geographic distribution and most remaining populations are threatened by habitat loss and fragmentation. Development of in situ and ex situ conservation strategies is fundamental for the protection and re-introduction of the species in their natural habitat. In this dissertation the life history, symbiotic mycorrhizal fungal associations, and habitat characteristics of S. parksii and sympatric congener Spiranthes cernua were investigated by the use of in situ, and ex situ methods. The central research objective was to investigate the orchid-fungal relationship and its distribution in natural habitats and to provide critical information for conservation of the species. Population dynamics and reproductive phenology of both species were studied from 2007 to 2013. Demographic parameters, cost of reproduction, and response to environmental conditions were analyzed. Results indicate that probability of flowering is strongly influenced by vegetative size and environmental conditions in the year preceding a flowering event. Reproductive effort resulted in a decrease in plant size, reducing the probability of flowering subsequently. Environmental conditions explained ?70% of the annual variation in the proportion of flowering plants and inflorescence characteristics. Mycorrhizal fungi associations and belowground phenology of both species were studied for three growing seasons. Data suggest that both species form generalist mycorrhizal associations with fungi tentatively classified, as Epulorrhiza sp., and Ceratobasidium sp. Both orchids sustain mycorrhizal colonization throughout their life cycle. However, seasonal changes in mycorrhization reveled a distinctive annual cycle of infection and digestion of fungal hyphae. Seed viability, in situ germination, seedling development, and mycorrhization were examined in situ by using orchid seed baits. Results suggest that S. parksii seeds are short-lived and germination is constrained by rapid reduction in seed viability, prevailing environmental conditions, and distribution of compatible mycorrhizal fungi. Data indicates a small optimal window for recruitment restricted to the first spring after dispersal. Microhabitat characteristics of S. parksii were compared to microsites of sympatric S. cernua, historical S. parksii microsites and vacant microsites currently not supporting either orchid. Vegetation, edaphic, and environmental parameters were evaluated. The study found that microsites currently occupied by S. parksii differ significantly from other types in canopy cover, leaf litter, herbaceous cover, and soil pH. Furthermore, woody encroachment may significantly affect the availability of suitable microsites not only as a result of altered light environments, but also due to changes in community composition, microclimatic, and edaphic conditions.Item The Pecan Street Project : developing the electric utility system of the future(2009-08) Smith, Christopher Alan; Eaton, David J.; Webber, Michael E., 1971-The Pecan Street Project (PSP) is a public-private initiative that seeks to establish the City of Austin and its electric utility, Austin Energy (AE), as leaders in developing the electric utility system of the future and clean energy economy. The four main components of the project are to: 1) develop a local, public-private consortium dedicated to research and development of clean energy technologies and distributed power generation; 2) open the city’s electric grid to act as a lab to test emerging clean energy technologies; 3) develop a new business model to ensure AE’s continued profitability; and 4) show the world how the new business and systems model can work. This report provides a case study of PSP and describes an analytical approach for evaluating projects, programs, and policies proposed by PSP working groups to develop a cleaner, more efficient electric system. This report includes a history of the project, discusses opportunities and challenges identified by PSP, and evaluates the potential economic, environmental, system, and other impacts of different project ideas through a technical analysis. This report concludes with a series of recommendations to PSP and identifies policy implications for the City of Austin, AE, other policymakers, and other electric utilities.