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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Direct Policy Search for Adaptive Management of Flood Risk

Jingya Wang (15354619) 29 April 2023 (has links)
<p> Direct policy search (DPS) has been shown to be an efficient method for identifying optimal rules (i.e., policies) for adapting a system in response to changing conditions. This dissertation describes three major advances in the usage of DPS for long-range infrastructure planning, using a specific application domain of flood risk management. We first introduce a new adaptive way to incorporate learning into DPS. The standard approach identifies policies by optimizing their average performance over a large ensemble of future states of the world (SOW). Our approach exploits information gained over time, regarding what kind of SOW is being experienced, to further improve performance via adaptive meta-policies defining how control of the system should switch between policies identified by a standard DPS approach (but trained on different SOWs). We outline the general method and illustrate it using a case study of optimal dike heightening extending the work of Garner and Keller (2018). The meta-policies identified by the adaptive algorithm show Pareto-dominance in two objectives over the standard DPS, with an overall 68% improvement in hypervolume. We also see the improved performance over three grouped SOWs based on future extreme water levels, with the hypervolume improvements of 90%, 46%, and 35% for low, medium, and high water level SOWs respectively. Additionally, we evaluate the degree of improvement achieved by different ways of implementing the algorithm (i.e., different hyperparameter values). This provides guidance for decision makers with different degrees of risk aversion, and computational budgets. </p> <p>Due to simplifying assumptions and limitations of the adaptive DPS model used in the chapter, such as uniform levee design heights, the Surge and Waves Model for Protection Systems (SWaMPS) is presented as a more realistic application of the DPS framework. SWaMPS is a process-based model of surge-based flood risk. This chapter marks the first implementation of DPS using a realistic process-based risk model. The physical process of storm surge and rainfall is simulated independently over multiple reaches, and different frequencies are explored to manage the production system in SWaMPS. The performance of the DPS algorithm is evaluated versus a static intertemporal optimization.</p> <p>The computational burden of evaluating the large ensemble of SOWs to include possible future events in DPS motivates us to apply scenario reduction methods to select representative scenarios that more efficiently span an uncertain parameter space. This allows us to reduce the runtime of the optimization process. We explore a range of data-mining tools, including principal component analysis (PCA) and clustering to reduce the scenarios. We compare the computational efficiency and quality of policies to this optimization problem with reduced ensembles of SOWs.</p>
32

Bishop Peak Natural Reserve Conservation Plan Update

Bush, Douglas J 01 June 2015 (has links) (PDF)
My master's project is updating the Conservation Plan for the Bishop Peak Natural Reserve (BPNR) in San Luis Obispo, California. It is a professional project for the City of San Luis Obispo, supported by City policy that requires continued management of its open space network through management plans unique to each property. As one of the city's most visited open spaces and one of its most visible natural landmarks, the Bishop Peak Natural Reserve is in need of continued management and oversight. While much of the work in developing the plan focused on identifying issues and developing responsive policy, this background report takes a step back, focusing on the underlying principles and municipal policies which direct those efforts. This paper serves as a background report for the planning process including an overview of methodology and policy development. One of the primary goals set forth in the BPNR update process is to improve of management capacity and increase the potential for successful implementation. To accomplish this, the reports shows how aspects of an Adaptive Management approach can be integrated into plan review and development. This background report is intended to complement the plan itself and therefore issues not covered within this report are covered within the plan.
33

Habitat Conservation Plan Implementation: Keeping Promises for Adaptive Management Within a "No Surprises" Policy

Smith, Bernice Loretta 09 December 2005 (has links)
Adaptive management is an approach to problem solving that acknowledges uncertainty. Adaptive management involves a systematic and rigorous process of learning from the outcomes of management actions, accommodating change and improving management. Plans, policies or management strategies influenced by new information and learning, are modified. This study examines the implementation of adaptive management for endangered and threatened species covered in Habitat Conservation Plans (HCP). Introduced in 1982 as an amendment to the Endangered Species Act (ESA), Habitat Conservation Plans are negotiated agreements that mitigate the incidental "take" (killing, harming) of endangered and threatened species during a development or resource extraction project. However, scholars found the scientific basis of approved HCPs to be inadequate and the efficacy of prescribed mitigation measures untested implying the need for adaptive management during implementation. This case study evaluation investigates HCP landowner compliance and progress within the parameters of the federal 1994 "No Surprises" policy. That policy limits landowner liability and responsibility for additional conservation action due to failed mitigation measures during HCP implementation. "No Surprises" assumes we can predict all the consequences of implementing a HCP. The policy seems to work against the objectives of adaptive management to improve scientific knowledge and modify action. The cases include the Central Cascades HCP implemented in the Central Cascades of Washington and the Orange Central Coastal County HCP implemented within a nature reserve in Orange County, California. The study assesses the strengths and weaknesses of adaptive management implementation for protecting endangered species and their habitat, and 2) recommends mid-course corrections for improving adaptive management before HCP maturity. / Ph. D.
34

Spatial Tools for Management of Protected Natural Areas: Case Studies in Camping Management and Trail Impact Assessment

Arredondo, Johanna Rochelle 03 November 2023 (has links)
This dissertation comprises two distinct journal articles, each contributing significant advancements to recreation ecology by examining the effectiveness of various spatial tools in camping and trail management. The first article leverages strategic spatial planning, considering topography and spacing, to limit camping impacts and enhance visitor experiences. It investigates the long-term effectiveness of a sustainable camping management strategy on the Appalachian Trail, whereby protected area managers select and actively encourage or require visitors to camp on excavated "side-hill" campsites in sloping terrain. One of the most degraded camping locations along the popular Appalachian Trail was selected for this longitudinal study, which, in May 2002, involved the closure of 19 existing campsites in flat terrain, with use shifted to 14 newly constructed side-hill campsites in adjacent sloping terrain. Over the subsequent 17 years, the recovery of the closed campsites and the evolution of the newly established side-hill campsites were monitored and assessed. Results from this study reveal that a multifaceted approach integrating both direct and indirect management actions successfully achieved their management objectives to sustain the site's exceptionally high use while minimizing both resource and social impacts. This study highlights the ability of constructed side-hill campsites to resist expansion over time and provides valuable findings, insights, and "lessons learned" to guide protected area managers in selecting and implementing effective management strategies and actions in other high-use settings. The second study evaluates terrestrial photogrammetry as a spatial tool for trail impact assessment. Protected natural areas like Joshua Tree National Park (JTNP) rely heavily on trails to facilitate visitor access while spatially concentrating environmental impacts to their treads. Assessing the condition of these trails is difficult due to the logistical challenges inherent in conventional field data-gathering techniques. While technological advancements such as Uncrewed Aerial Vehicles (UAV) introduce Structure-from-Motion (SfM) capabilities for trail monitoring, they are not without limitations, including prohibitive costs, legal restrictions, and operational challenges, particularly when monitoring trails enveloped by canopy cover. This study presents a novel approach to trail assessment using terrestrial photogrammetry, wherein a consumer-grade camera captures high-resolution imagery that is processed using SfM techniques. The study compared manual measurements of 46 trail transects in JTNP with measurements from Digital Elevation Models (DEMs) generated from SfM point clouds. The outcomes revealed a high level of agreement between the two methods, with the measurements derived from photogrammetric DEM data exhibiting consistently higher values compared to the field measurements, especially in the central regions of the transects. A statistically significant positive relationship between transect width and mean differences between GIS and field tread incision measurements suggests that the disparity may arise from the sagging of the tape measure across the trail, indicating photogrammetric methods might offer greater accuracy. The paper outlines methods for capturing high-resolution 3D trail data using cost-effective techniques and discusses the practicality and possibilities of using the technique in trail monitoring programs. This has far-reaching implications and positions terrestrial photogrammetry as a compelling alternative to drone-based acquisitions, particularly in areas where UAV operations are restricted, discouraged, or impractical. / Doctor of Philosophy / This dissertation contains two journal articles, each contributing significant advancements to recreation ecology by examining the effectiveness of various spatial tools in camping and trail management. The first paper assesses a sustainable camping strategy on the Appalachian Trail, where managers guide visitors to use designated campsites built into steep terrain, called "side-hill" campsites. One of the most degraded camping locations along the popular Appalachian Trail was selected for this study, and in May 2002, 19 existing campsites in flat terrain were closed, and use was shifted to 14 newly constructed side-hill campsites in nearby steeper terrain. Over 17 years, researchers measured the recovery of the old sites and the evolution and impacts associated with the new ones. The results show the new approach successfully prevented the expansion of campsites, a chronic problem in popular camping areas in flat terrain. Success is attributed not only to the physical relocation of campsites but also to the closing of old campsites with fencing, educating visitors about sustainable camping practices, enforcing regulations, and maintaining the sites. This study highlights the ability of constructed side-hill campsites to resist expansion over time and provides valuable findings, insights, and "lessons learned" to guide protected area managers in selecting and implementing effective management strategies and actions in other high-use settings. The second study in this dissertation introduces an innovative method for assessing the impact on trails in protected areas like Joshua Tree National Park (JTNP). Maintaining hiking trails is crucial as they provide visitor access while spatially concentrating environmental impacts to their treads. However, evaluating their condition is complex due to challenges associated with traditional data collection methods. While drones offer some advancements, they come with their own set of issues, including high costs, legal hurdles, and difficulties operating in areas with dense tree cover. This research presents a novel approach through terrestrial photogrammetry, a technique that uses photos of an object taken at different angles to create detailed 3D models with specialized software, a process known as Structure-from-Motion. The study involved a detailed comparison of traditional manual measurements from 46 trail sections in JTNP to measurements obtained from these 3D models. Results suggest photogrammetric methods might offer greater accuracy than manual measurements. The paper outlines methods for capturing high-resolution 3D trail data using cost-effective techniques and discusses the practicality and possibilities of using the technique in trail monitoring programs. This has far-reaching implications and positions terrestrial photogrammetry as a compelling alternative to drone-based acquisitions, particularly in areas where UAV operations are restricted, discouraged, or impractical.
35

Modélisation de l'hydrosystème Vaccarès : contribution à une gestion adaptative des ressources en eau dans le delta du Rhône, France / Modelling of the Vaccarès Hydrosystem : contribution to an adaptive management of water resources in a deltaic context (Rhône delta, France).

Loubet, Aurelien 09 February 2012 (has links)
On se propose d'étudier l'hydrosystème Vaccarès, partie centrale du delta du Rhône, parfait exemple d'interrelations fortes entre l'homme et le milieu naturel. L'approche s'est déroulée en trois parties. L'acquisition et le traitement de données hydrologiques nous ont permis de caractériser la dynamique hydro-saline de ce système complexe. A partir d'une analyse plus approfondie nous avons établi les bilans hydro-salins et sédimentaires à l'échelle du complexe lagunaire. Grâce à un suivi de 18 années, les bilans sédimentaires dévoilent un déficit sédimentaire de 19 500 tonnes quand on ne prend pas en compte les apports exceptionnels des eaux d'inondation en 1993 et 1994. Un tel déficit, s'il perdure, ne fera qu'aggraver le différentiel d'altitude entre la mer et le delta, entrainant par la force des choses une salinisation du système non désirée par la plupart de ses acteurs. Dans un deuxième temps, nous avons procédé à l'implémentation et à la validation du modèle hydrodynamique du complexe lagunaire du Vaccarès. Son utilisation s'est tournée vers une complémentarité avec le modèle conceptuel de l'Hydrosystème Vaccarès. Ce dernier, baptisé Hydro-CAM, après avoir bénéficié d'une phase de calage et validation, a été exploité afin de tester la dynamique du système dans une démarche prospective. L'objectif ici, qui constitue le troisième temps de ces travaux de thèse, a été d'explorer par simulation les trajectoires possibles d'évolution de l'hydrosystème en termes de bilan d'eau et de sel, et ce d'après des scénarios construits sur les paramètres hydro-climatiques (changement climatique, augmentation du niveau marin) et anthropiques / The studied site is the Vaccarès hydrosystem, the central part of the Rhône delta and a good example of strong relationship between humans and a natural area. Through the data acquisition and data processing, we characterised the hydro-saline dynamic of this complex hydrosystem from 1993 to 2008. From a further analysis, we established first the hydro-saline and sedimentary balance across the lagoon complex. Through a monitoring of 16 years, the sedimentary balance revealed a sediment deficit of about 19'500 tons when we disregard the outstanding contributions of flooding waters in 1993 and 1994. If this deficit persists, the difference in altitude between the sea and the delta will tend to increase. This will result by a salinization of the system, unwanted by the most of his actors. To investigate these consequences, we conceived a hydrodynamic model of the Vaccarès lagoon complex, capable to simulate water levels and salinities. The model, named Hydro-CAM, was calibrated and validated in terms of water levels and salinities in three sub-units of the lagoon complex. It was then used to test the system dynamics in a prospective approach. The objective in this thesis work was to explore by simulation the possible trajectories of the evolution of the Hydrosystem in terms of water and salt balance. Simulations were based on scenarii constructed from climate parameters and anthropogenic parameters (water management, constructions, land use on drainage basins, etc.). The results revealed the vulnerability of this complex system to various risks which it is already facing and for which the intensification and/or increase can be expected in the future
36

Regeneração natural de fragmentos de florestas nativas inseridos em paisagens agrícolas muito fragmentadas do noroeste de São Paulo / Natural regeneration of native forest fragments in highly fragmented agricultural landscape of northwest São Paulo

Figueiredo, Pablo Hugo Alves 02 December 2016 (has links)
O noroeste de São Paulo, transição entre a Floresta Atlântica e o Cerrado, é uma das regiões mais fragmentadas do estado. Investigando a regeneração natural de remanescentes florestais é possível compreender como a diversidade de espécies e os processos ecológicos são mantidos nessas paisagens agrícolas muito fragmentadas, gerando subsídios para ações de conservação e restauração. Nesse sentido, as perguntas norteadoras deste estudo foram: 1) o conhecimento do componente regenerante de remanescentes florestais inseridos em matrizes agrícolas muito fragmentadas permite avaliar a perpetuação dos mesmos ao longo do tempo? 2) quais fatores, de qualidade de hábitat ou de estrutura da paisagem, exercem maior influência sobre composição, densidade e riqueza de espécies no componente regenerante desses remanescentes florestais? Para isso, foi comparada a riqueza, diversidade e composição de espécies entre o componente regenerante (altura >1,0 m e DAS< 5 cm) e arbóreo (DAS> 5 cm) de 18 fragmentos de florestas nativas do noroeste de São Paulo. Em seguida, foi analisada a relação entre a qualidade do hábitat (soma de bases do solo, teor de argila do solo e frequência de incêndio) e estrutura da paisagem (conectividade, isolamento e tamanho total do fragmento) com os valores descritivos do componente regenerante. Foram registrados no componente regenerante 5.989 indivíduos e 207 espécies, o que equivale a uma média de 4968±3584 ind.ha-1 e 33±14 espécies por fragmento. As famílias mais ricas foram Fabaceae (28 espécies), Myrtaceae (25), Rubiaceae (21) e os gêneros foram Eugenia (12), Ocotea (6), Campomanesia (5) e Psychotria (5). Comparado ao componente arbóreo, o componente regenerante apresentou significativamente menor riqueza e diversidade &alpha;, pois 71% das espécies do componente arbóreo não foram registradas na regeneração natural. Porém, ambos componentes apresentaram composição florística significativamente correlacionada. Com relação à diversidade &beta;, em média, o componente regenerante apresentou valor significativamente maior entre os fragmentos. A qualidade de habitat foi mais importante para explicar a estrutura e riqueza da comunidade regenerante. Frequência de incêndio contribuiu negativamente para a densidade total comunidade e de indivíduos zoocóricos, clímaces de sub-bosque e de dossel, assim como para a riqueza de espécies zoocóricas, pioneiras e colonizadoras. A riqueza de especialistas de florestas apresentou relação positiva com a soma de bases enquanto para a riqueza e densidade de generalistas a relação foi negativa. Soma de bases e teor de argila no solo foram as variáveis mais relacionadas com a composição florística da comunidade regenerante. Dentre as variáveis de paisagem, conectividade relacionou-se negativamente com a densidade de espécies generalistas enquanto área do fragmento apresentou relação positiva com a densidade de zoocóricas com propágulos de tamanho médio. Portanto, a regeneração natural representou um subconjunto de espécies do componente arbóreo com menor diversidade, riqueza e número de espécies compartilhadas entre os fragmentos e por isso seriam necessárias ações de manejo adaptativo para garantir a perpetuação dos remanescentes florestais nessas paisagens muito fragmentadas. Frequência de incêndios foi o principal fator comprometedor da perpetuação da biodiversidade e a importância do gradiente edáfico para composição de espécies dos remanescentes florestais da região foi confirmada. / The northwestern São Paulo, a transition area between the Atlantic Forest and Cerrado, is one of the most fragmented region of the state. Investigating the sapling community of forest communities would be possible understanding how species diversity and ecological processes are maintained in this kind of landscape and therefore it would help creating subsides for forest restoration. For this reason, the questions of this research were: 1) Does the survey of sapling community of forest remnants in highly fragmented agricultural landscape allows assessing their self-perpetuating capacity? 2) Which factors of habitat quality or landscape structure exerts greater influence on the species composition, density and species-richness of the sapling community of these forest remnants? Thus, it was assessed the sapling community (height >one, 0 m and DSH< 5,0 cm) density and compared the observed and the relative species-richness of functional groups, &alpha; and &beta; diversity and species composition to the tree community (DSH> 5,0 cm) in the same forest remnant. After that, was assessed the influence of habitat quality (soil sum of bases, soil clay content, fire frequency) and landscape structure (functional connectivity, isolation and total size of these forest remnants) on the descriptive values of sapling communities. Overall, the sapling community showed 5.989 individuals and 207 species that represent on average 4968±3584 ind.ha-1 and 33±14 species for forest fragments. The botanic families with higher species-richness were Fabaceae (28 species), Myrtaceae (25), Rubiaceae (21) and genera were Eugenia (12), Ocotea (6), Campomanesia (5) e Psychotria (5).Compared to the tree community, the sapling community had significantly smaller species-richness (observed and estimated) and &alpha; diversity, because 71 % of species from the tree community did not occur in sapling community. However, both communities had species composition significantly correlated, the sapling communities showed significantly higher &beta; diversity than trees communities. The habitat quality were more important to explain the density, species-richness and species composition of the sapling communities. Fire frequency contributed negatively to species-richness of zoochorous species, pioneer species and colonizers group (species found only at sapling community) and to the sapling density of zoochorous species, shade-tolerant canopy species and shade-tolerant understory species. The species-richness of forest-specialist species was positively related to the soil sum of bases but to the sapling density and species-richness of generalist species was found the opposite relation. Similarly, sum of base and clay content were the variables most related to the species composition of sapling community. Functional connectivity and the total area of the forests fragments explained only the density of generalist and zoochorous medium-seeded species, but with relatively smaller importance than the habitat quality variables. Thus, the sapling community of these forest remnants represented a subset of the tree community but with significant smaller diversity, species richness and number of common species among fragments and then adaptive management efforts is needed to assist long-term biodiversity persistence in forests fragments in highly fragmented agricultural landscape. Frequent fires was the main factor affecting negatively the biodiversity perpetuation and the importance of an edaphic gradient to species composition of forests remnants in the region was validated.
37

Electricity planning in West Africa: which way forward? An adaptive management perspective on energy policy

Soumonni, Ogundiran 20 September 2013 (has links)
Africa’s quest for economic development will require the increased availability and use of its abundant energy resources. Nevertheless, most of its rural population remains without access to modern energy services and urban residents typically only enjoy an intermittent supply of electricity. The dominant approach to energy planning in West Africa is top-down and centralized, emphasizing electricity generation from large dams or fossil-fueled plants and subsequent grid extension to reach more customers. However, an alternative and complementary paradigm is that of decentralized or Distributed Generation (DG), which stresses small-scale, on-site generation of power and offers a bottom-up approach to energy development. The goal of this dissertation project is to assess the various options for regional electrification and integration through a holistic analysis of the set of existing technologies and policies for deploying them. The main organ of the Economic Community of West African States (ECOWAS) for regional electricity planning is the West African Power Pool (WAPP) and its primary policy document, the “Master Plan”, addresses regional power supply shortage through centralized planning. Both the WAPP policy documents and the majority of the country-level planning documents are considered to be based on a traditional, empiricist, policy analysis that appears to provide value-neutral solutions and generalizations. In contrast, the analysis provided in this project situates itself within the post-positivistic, deliberative and more contextual approach to policy analysis in order to compare the centralized approach to generation with a distributed approach, which is currently marginal in the region. It uses the Adaptive Management (AM) framework for this analysis, particularly because of the way it deals with ecological resilience in the face of widespread uncertainty. The main policy issue that this project seeks to address is the need for an integrated energy-environment planning process, which is currently lacking in West Africa, so as to achieve long term sustainability. Adaptive management offers policy makers a holistic lens with which to view energy policy, but there are very few examples of institutions that have attempted to implement it in practice anywhere in the world. These instances, however, represent a valuable historical reference point for future policy research and management efforts that seek to explore this approach. In alignment with that objective, this dissertation first provides an overview of the concept of adaptive management in general, and its application to energy problems in particular. Secondly, the research project undertakes a policy analysis of the ECOWAS strategy for electrification, based on a stakeholder analysis, a review of life cycle assessments of existing energy technologies, the expected outcomes of the electricity sector, and a set of traditional criteria for evaluating public policies. In order to further examine the question of electricity access, it carries out a quantitative analysis of the electricity demand and supply in the region. It uses a modeling approach that is based on the logic of AM to determine whether or not the energy requirements for broad based electrification can be met through distributed renewable power, which is currently a negligible component of the generation resource portfolio in West Africa. The dissertation proceeds to carry out a retrospective analysis of three cases in the U.S. where elements of AM have already been applied to energy planning in order to investigate some of the critical determinants for its successful implementation to date. This assessment then informs a prospective analysis of three West African cases that have ideal characteristics for experimentation with AM to determine to what extent similar concepts have been used, or may be employed in the future. The AM framework also calls for the consideration of local values, which should be open to revision in the face of real situations. To this end, the prospective analysis includes three additional place-sensitive criteria, so as to ensure that the framework remains viable in a different socio-political context. The AM analyses are then extended to include a discussion of learning and innovation in clean energy technologies, drawing from the Chinese, Danish and South African experiences. The results suggest that a strong and consistent political will that is in alignment with an explicit social policy is needed to initiate and implement broad-based electrification plans, but that stakeholder participation is critical to their success. In addition, the adoption of multiple instruments and the selection of a diverse range of energy resources were found to be more effective than an overreliance on a single dominant scheme so as to allow room for policy learning. Furthermore, the results confirm that a holistic approach to managing ecosystems associated with electric power production is a fruitful way to integrate ecological considerations with social and economic factors throughout the development of a project. This type of systemic methodology should also include the building of technological capability and the development of innovation capacity in order to address the unique socio-economic context and the rapidly-changing climatic conditions in West Africa. Finally, the articulation of a planning philosophy that engages the values and sensibilities of the people in a particular place, and that is rooted in them, was found to be a critical factor for increasing the level of public participation in management activities in order to achieve more equitable and democratic outcomes.
38

The Increasing Prevalence of Smaller Fish in Highly Exploited Fisheries: Concerns, Diagnosis and Management Solutions.

Spencer, Stephen Unknown Date
No description available.
39

The Increasing Prevalence of Smaller Fish in Highly Exploited Fisheries: Concerns, Diagnosis and Management Solutions.

Spencer, Stephen 06 1900 (has links)
A decline in the size of fish within a population is concerning. Large-sized fish are ecologically important and valued for social and economic reasons. Following widespread collapses from angling overharvest, the densities of Walleyes Sander vitreus in Albertas lakes increased rapidly with large-minimum-size limits. Anglers were unhappy, however, as catch rates increased (>1 Walleyes*hour-1) but fish remained small and did not exceed the minimum size limit. The two alternate explanations for the small, yet old Walleyes were either compensatory growth because of high density (stunting) or size-selective mortality (overfishing). Size-selective mortality has evolutionary consequences. Paradoxically, the management solutions for these problems are in opposition (more harvest versus less harvest), and a wrong diagnosis could exacerbate the problem. I used nested hypotheses, and implemented active adaptive management at several Alberta lakes, to diagnose the causal mechanism creating the small fish problem. For inferences on the source of the mortality, I analysed backcalculated growth rates from pelvic fins. Walleyes that had fast-growth to an early maturity, and then subsequent slow-growth, had greater survival. This hockey stick-shaped growth allows for successful reproduction while the Walleyes remain below the minimum size limit, avoiding harvest. Using changes to sport fishing regulations, I then modified angler effort and harvest at four different Alberta lakes to increase or decrease size-selective harvest and Walleye densities. I found that size-selective mortality from angling rapidly truncated the population-size structure. With concerns of evolutionary consequences because of evidence of size selective harvest, I used an age- and size-structured, single-species model, parameterized with data from Albertas Walleye fisheries, to evaluate the selectiveness of various management regulations. I found that the 50-cm minimum size limit used to recover Albertas Walleye populations did indeed select for the hockey stick life history, although this regulation allowed for sustainable populations (>5 Walleyes*hectare-1) and angler effort up to 16 angler-hours*ha-1*year-1. The optimal regulation to reduce life history selection and allow for population sustainability was a 40-50 cm harvest-tag regulation. This regulation reversed the selection for the hockey stick life history, yet produced sustainable fish densities and allowed angler effort up to 30 angler-hours*ha-1*year-1. However, increasing angler-noncompliance reduced the sustainability of this regulation. / Wildlife Ecology and Management
40

Complex Adaptive Systems Simulation-Optimization Framework for Adaptive Urban Water Resources Management

Giacomoni, Marcio 2012 August 1900 (has links)
Population growth, urbanization and climate change threaten urban water systems. The rise of demands caused by growing urban areas and the potential decrease of water availability caused by the increase of frequency and severity of droughts challenge the continued well-being of society. Due to increasing environmental and financial constraints, water management paradigms have shifted from supply augmentation to demand management, and water conservation initiatives may efficiently decrease water demands to more sustainable levels. To provide reliable assessment of the efficiencies of different demand management strategies, new modeling techniques are needed that can simulate decentralized decisions of consumers and their interactions with the water system. An integrated simulation-optimization framework, based on the paradigm of Complex Adaptive Systems, is developed here to model dynamic interactions and adaptations within social, built, and natural components of urban water systems. The framework goes beyond tradition engineering simulations by incorporating decentralized, heterogeneous and autonomous agents, and by simulating dynamic feedback loops among modeling components. The framework uses modeling techniques including System Dynamics, Cellular Automata, and Agent-based Modeling to simulate housing and population growth, a land use change, residential water consumption, the hydrologic cycle, reservoir operation, and a policy/decision maker. This research demonstrates the applicability of the proposed framework through a series of studies applied to a water supply system of a large metropolitan region that is located in a semi-arid region and suffers recurrently from severe droughts. A set of adaptive demand management strategies, that apply contingency restrictions, land use planning, and water conservation technologies, such as rainwater harvesting systems, are evaluated. A multi-objective Evolutionary Algorithm is coupled with the CAS simulation framework to identify optimal strategies and explore conflicting objectives within a water system. The results demonstrate the benefits of adaptive management by updating management decisions to changing conditions. This research develops a new hydrologic sustainability metric, developed to quantify the stormwater impacts of urbanization. The Hydrologic Footprint Residence captures temporal and spatial hydrologic characteristics of a flood wave passing through a stream segment and is used to assess stormwater management scenarios, including Best Management Practices and Low Impact Development.

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