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1
Caeiro, Sandra Sofia Ferreira da Silva. "Environmental data management in the Sado Estuary." Doctoral thesis, FCT - UNL, 2004. http://hdl.handle.net/10362/1117.
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Estuaries are perhaps the most threatened environments in the coastal fringe; the coincidence of high natural value and attractiveness for human use has led to conflicts between conservation and development. These conflicts occur in the Sado Estuary since its location is near the industrialised zone of Peninsula of Setúbal and at the same time, a great part of the Estuary is classified as a Natural Reserve due to its high biodiversity. These facts led us to the need of implementing a model of environmental management and quality assessment, based on methodologies that enable the assessment of the Sado Estuary quality and evaluation of the human pressures in the estuary. These methodologies are based on indicators that can better depict the state of the environment and not necessarily all that could be measured or analysed. Sediments have always been considered as an important temporary source of some compounds or a sink for other type of materials or an interface where a great diversity of biogeochemical transformations occur. For all this they are of great importance in the formulation of coastal management system. Many authors have been using sediments to monitor aquatic contamination, showing great advantages when compared to the sampling of the traditional water column. The main objective of this thesis was to develop an estuary environmental management framework applied to Sado Estuary using the DPSIR Model (EMMSado), including data collection, data processing and data analysis. The support infrastructure of EMMSado were a set of spatially contiguous and homogeneous regions of sediment structure (management units). The environmental quality of the estuary was assessed through the sediment quality assessment and integrated in a preliminary stage with the human pressure for development. Besides the earlier explained advantages, studying the quality of the estuary mainly based on the indicators and indexes of the sediment compartment also turns this methodology easier, faster and human and financial resource saving. These are essential factors to an efficient environmental management of coastal areas. Data management, visualization, processing and analysis was obtained through the combined use of indicators and indices, sampling optimization techniques, Geographical Information Systems, remote sensing, statistics for spatial data, Global Positioning Systems and best expert judgments. As a global conclusion, from the nineteen management units delineated and analyzed three showed no ecological risk (18.5 % of the study area). The areas of more concern (5.6 % of the study area) are located in the North Channel and are under strong human pressure mainly due to industrial activities. These areas have also low hydrodynamics and are, thus associated with high levels of deposition. In particular the areas near Lisnave and Eurominas industries can also accumulate the contamination coming from Águas de Moura Channel, since particles coming from that channel can settle down in that area due to residual flow. In these areas the contaminants of concern, from those analyzed, are the heavy metals and metalloids (Cd, Cu, Zn and As exceeded the PEL guidelines) and the pesticides BHC isomers, heptachlor, isodrin, DDT and metabolits, endosulfan and endrin. In the remain management units (76 % of the study area) there is a moderate impact potential of occurrence of adverse ecological effects and in some of these areas no stress agents could be identified. This emphasizes the need for further research, since unmeasured chemicals may be causing or contributing to these adverse effects. Special attention must be taken to the units with moderate impact potential of occurrence of adverse ecological effects, located inside the natural reserve. Non-point source pollution coming from agriculture and aquaculture activities also seem to contribute with important pollution load into the estuary entering from Águas de Moura Channel. This pressure is expressed in a moderate impact potential for ecological risk existent in the areas near the entrance of this Channel. Pressures may also came from Alcácer Channel although they were not quantified in this study. The management framework presented here, including all the methodological tools may be applied and tested in other estuarine ecosystems, which will also allow a comparison between estuarine ecosystems in other parts of the globe.
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Crandall, Lucas Earle. "Ecosystem-Based Management in the Morro Bay Watershed and Estuary." DigitalCommons@CalPoly, 2017. https://digitalcommons.calpoly.edu/theses/1723.
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The following thesis discusses the implementation of ecosystem-based management, an emerging concept in the field of environmental planning and management, in the Morro Bay watershed and estuary. Ecosystem-based management offers solutions to problems associated with human interaction within the natural environment; former President Barack Obama advised by the National Ocean Council, Pew Oceans Commission Report and the US Commission on Ocean Policy, has mandated implementation of this concept in coastal and marine systems (National Ocean Council, 2016). The theory behind ecosystem-based management challenges many tenets of existing natural resource management. This thesis finds the concept of ecosystem-based management as favorable despite tradeoffs and impacts of changing status quo. The preliminary research question asked if key criteria of ecosystem-based management were integrated into existing management plans of institutions such as the Coastal San Luis Resource Conservation District, Morro Bay National Estuary Program, and the San Luis Obispo Science and Ecosystem Alliance. The study answers this question through a document analysis of three local management plans. Survey and interviews were used to assess inconsistencies between management plan goals and on-the-ground implementation in the Morro Bay ecosystem. The results were used to incorporate tenets of ecosystem-based management into the Coastal San Luis Resource Conservation District’s five-year and annual strategic plan update.
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Hanna, Kevin S. "Integrated resource management, a review and evaluation of the Fraser River Estuary Management Program." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0001/NQ35173.pdf.
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McKelvey, Fionnuala. "Population ecology and fisheries management of the native oyster, Ostrea edulis L. in Lough Foyle." Thesis, University of Ulster, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241729.
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Perez-Sanchez, Eunice. "Coastal aquaculture and resources management in the Mecoacan estuary, Tabasco, Mexico." Thesis, University of Stirling, 2002. http://hdl.handle.net/1893/21435.
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By dealing with aspects of coastal aquaculture and resources management, an analysis is herein presented at the macro-scale using GIS techniques for the coastal zone of Tabasco state, and at the micro-scale with the description of the characteristics of a coastal community located in the Mecoacan estuary. Transfer of appropriate aquaculture technologies and introduction of sustainable farming systems are major challenges. The total area identified for aquaculture development through the GIS modelling accounted for 23 462 ha, 80% of which were located in the Centla Biosphere Reserve (Centla and Macuspana). The suitable area identified through the multi-criteria evaluation provided a structure in which requirements for aquaculture development could be met. An analysis of the fanning systems in the Mecoacan estuary was carried out to understand local attitudes, capabilities and processes and evaluate whether the potential identified by the GIS modelling can be realised. The results from participatory assessments showed that conditions within Mecoacan cooperatives have deteriorated and increasing interest in restructuring the organisations is regarded as a means of integrating employment and income generation alternatives such as aquaculture practices, to support and improve current levels of fisheries production, and to achieve gains in market development. The analysis of the economics of Mecoacan fishermen suggests that rural problems have not yet been engaged in progressive policies. It seems that previous forms of governance have been maintained to shore up power instead of laying the groundwork for viable rural production, as it is clear that some fishermen are competitive while others are not, regardless of whether or not they are associated in cooperatives. The large-scale exploitation of resources, degradation of the environment and increased conflict over resources in coastal communities suggest the need of an integrated multi-sectoral approach. A strategy towards an integrated coastal management for Tabasco coastal zone is discussed, including those related to aquaculture development.
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Montgomery, Jacob R. "Foodweb Dynamics in Shallow Tidal Sloughs of the San Francisco Estuary." Thesis, University of California, Davis, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10620274.
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Non-parametric ANOVA tests, ordination, and Bayesian generalized linear models (GLMs) revealed strong physical, chemical, and biological differences among the study sites. Lower trophic foodweb indexes (i.e., chlorophyll-a (chl-a) concentration, zooplankton biomass, and planktivorous fish abundance) were investigated in association with environmental variables in three terminal sloughs within the upper San Francisco Estuary. Non-metric multidimensional scaling (NMDS) showed tight clustering of data from each site. Kruskal-Wallis tests confirmed the NMDS by identifying statistically-significant differences among sites and between paired sites within each of the three regions (i.e., Cache Slough, Lindsey Slough, Suisun Marsh). Bayesian GLMs identified temperature and dissolved inorganic nitrogen as primary correlates with chl-a concentration, and temperature and chl-a concentration as primary correlates with zooplankton biomass. Planktivorous fish data were insufficient to fit a GLM. Up-slough sites in Cache Slough and Suisun Marsh consistently showed greater abundances of chl-a and zooplankton relative to down-slough sites in each region. However, that pattern was reversed in Lindsey Slough. Possible reasons for this discrepancy include adjacent land-use and management practices, relative importance of alternate foodweb pathways, and the presence of a major water diversion. This study emphasizes the importance of site-specific foodweb dynamics and local anthropogenic effects, particularly in relation to design of tidal wetland restoration projects.
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Hushlak, Anna A. "Integrating traditional ecological knowledge in South Africa's small-scale fisheries: the Olifants Estuary Gillnet Fishery." Master's thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/11608.
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Includes abstract.Includes bibliographical references.
Increasingly, managers and scientists are recognizing the importance of understanding small-scale fisheries as complex socio-ecological systems. As a result, managing fisheries is no longer only about managing fish but also about managing people. One mechanism for incorporating the human dimension into small-scale fishery management is knowledge integration. Through pluralising epistemologies, knowledge integration fosters participative dialogue, improves current knowledge bases, and strengthens management...
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Waldron, Miranda Elizabeth. "The importance of water levels in the management of the Klein River Estuary, Hermanus." Master's thesis, University of Cape Town, 1987. http://hdl.handle.net/11427/15848.
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Bibliography: pages 85-89.The Klein River Estuary is situated at Hermanus in the Western Cape, South Africa. The estuary mouth is normally closed by a sand berm during the summer and open to the sea during the wetter winter months. The estuary forms a shallow lagoon which is becoming increasingly popular for recreational activities. Several management problems have arisen which are now becoming important with the increase in recreational pressure. The main problems are: uncertainty about appropriateness of water levels, marine sand influx and accumulation, flooding of low lying developments, flooding of agricultural lands, decrease in fish catches and indecision about the ideal position of the estuary mouth in the sand berm. This study concentrates mainly on the effects of different possible water levels. The conclusion is that the estuary water level should be permitted to rise at least as high as the highest level investigated. The estuary should be allowed to breach the sand berm. Developments on low lying land, prone to flooding, should be prohibited and only those structures which would not be damaged by flooding should be allowed in such areas.
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Boyd, David Miller. "FRNA Coliphages as a Viral Indicator of Sewage Pollution in an Estuary." W&M ScholarWorks, 1990. https://scholarworks.wm.edu/etd/1539617616.
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Fifield, Michael John. "Morphology, Dynamics and Hazard Management of the New River Lagoon, Westland, New Zealand." Thesis, University of Canterbury. Geography, 2012. http://hdl.handle.net/10092/7232.
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Coastal lagoon systems are complex and dynamic environments that respond rapidly to the changes of fluvial, marine, climatic and anthropogenic influences. The purpose of this research was to investigate the morphology and dynamics of the New River Lagoon before and after the implementation of engineering outlet management using a methodological framework to analyse active process environments. This information was then used to determine the functional effectiveness of engineering management at reducing the risk of flooding and erosion to the local community and imposing minimal impacts on the environmental integrity of the lagoon system.
This investigation used a multidisciplinary approach to investigate the morphology and dynamics of the New River Lagoon in relation to active process environments. Outlet dynamics, lagoon channel structure and adjacent shoreline stability were assessed over a decadal timescale prior to engineering management by analysing temporal aerial photographs. Following engineering management, the hydrology of the lagoon was investigated, along with the relationship between morphological changes to the artificial lagoon outlet and changes in lagoon hydrology, local wave climate and local precipitation levels. Water depth, conductivity and temperature records were used to explain lagoon hydrology and Global Navigation Satellite Surveying (GNSS) and weekly oblique photographs were used to explain and document changes in outlet morphology. Wave and rainfall data were used to explain the balances between marine and fluvial environments and their affects on outlet dynamics.
Significant changes in lagoon morphology and dynamics were observed at the New River Lagoon between pre- and post-management periods, with the former considered more stable in terms of outlet migration patterns and hydrodynamics. The lagoon outlet prior to engineering management showed morphological characteristics similar to hapua-type systems, migrating along the coastline and forming shore-parallel outlet channels in response to the dominance of a strong longshore drift of sediment. Current outlet dynamics are restricted by artificial outlet management and typically cycle intermittently between open/closed phases in response to variable levels of rainfall and marine sediment supply; characteristics similar to Intermittently Open/Closed Lagoons (ICOLs) found in areas of Australia and South Africa. Hydrologically, the lagoon is considered to be located on a continuum between hapua and estuaries during pre- and post-management periods due to intermittent tidal influences. However, artificial outlet management has significantly increased the frequency and duration of tidal exchange, which now classifies the New River lagoon closer to an estuarine environment.
The artificial lagoon outlet and associated breakwater were effective at flushing high flows of water during the study period. However, the outlet was prone to blockage and migration; two morphological states capable of causing flooding. Currently, the greatest risks to flooding at the lagoon are flash floods, following dry periods where marine sediment has established a solid barrier across the outlet, during which water levels are already elevated.
Increases in tidal influences, lower lagoon water levels and an increase in lagoon salinity are a direct result of engineering management intervention. An increase in freshwater flushing through the lagoon outlet and deepened of the outlet channel to below sea level, allows for pronounced tidal influences during outlet opening. Restriction of the lagoon outlet from forming a natural migration outlet channel in the direction of littoral drift has meant the outlet is most often oriented perpendicular to the sea, as appose to at an angle away from the direction of incoming waves and currents, further increasing tidal influences.
In order to make sustainable management decisions, future management of the lagoon system must weight-up the effects of a high energy coastline to the integrity of the engineering structure, the impact of the structure on the lagoons environmental integrity and the outlets ability to become unstable and cause a flood risk.
The findings of this research have improved the understanding of the New River Lagoon system, and its response to engineering management intervention, while adding to the understanding of river-mouth lagoon systems both nationally and internationally.
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Goodhue, Nigel David. "Hydrodynamic and water quality modelling of the lower Kaituna River and Maketu Estuary /." The University of Waikato, 2007. http://hdl.handle.net/10289/2375.
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The Maketu Estuary is a shallow intertidal estuary (2.3 km2) located in the Bay of Plenty, North Island, New Zealand. The Kaituna River contributes the largest freshwater flow into the estuary through control gates. Lake Rotoiti and indirectly Lake Rotorua supply the base flow to the Kaituna River, with tributaries along the 50 km reach also significantly contributing to the flow. Water quality within the river is affected by elevated nutrients, faecal coliforms, high oxygen demand and algae concentrations derived from the lakes as well as contributions from tributaries and industrial and urban discharge. Through the use of a coupled hydrodynamic-biogeochemical numerical model ELCOM-CAEDYM, this study aims to examine the nutrient, phytoplankton and hydrodynamics of the Maketu Estuary and lower Kaituna River. Water quality and hydrodynamic measurements were sourced from Environment Bay of Plenty's data archives as well as a number of instrument deployments to collect water velocity, tidal elevation and salinity and temperature measurements during the course of this study. Included in the field work was a survey of the lower river and estuary bathymetry. Model simulations predicted that the maximum residence time in the Maketu Estuary is 1.5 days, occurring in the inner western region. Residence time in the lower river (mouth to 8.5 km upstream) is in the order of hours although some variations were predicted near the river mouth. Growth rates of four phytoplankton groups where assessed over a 15 day period in January 2004. In the Kaituna River ELCOM-CAEDYM predicted that the community growth rates were small with the exception of a slight increase in biomass of the two freshwater groups in a semi-detached river bend. The increase in the loop was correlated with an increase of residence time. In the estuary, marine diatoms showed the highest growth rates in the western region which is expected to relate to retention time and available nutrients. Dinoflagellates showed the smallest variation in predicted growth rates, most likely due to their broad salinity tolerance. The two freshwater species showed a reduction in abundance when mixed with marine water. A principle limiting factor to phytoplankton growth in both the river and estuary is the low residence time. A number of scenarios were simulated in the river and estuary by altering the forcing conditions in the model. A simulation of the increased nutrient load associated with the Rotoiti diversion wall revealed that phytoplankton growth in the river and estuary will not be significantly affected. Because of the close proximity of the control gates to the river mouth, a proportion of water drawn through the structure can be marine. By opening the old river channel, model simulations predicted that a reduction in salinity would be possible, however the outcome of complete freshwater is probably not achievable. Increasing the discharge volume from the river into the estuary was also simulated. The results indicated that increasing the freshwater inflow at Fords Cut would reduce the salinity in the estuary while increasing the net (residual) flow towards the estuary mouth. Increasing the flow would also result in a greater range of salinity in regions of the estuary. Changing the inflow location to the historic Papahikahawai Channel also affected the salinity in the estuary. The most significant effect of an inflow at this location was a reduction of the residual currents in the western region of the estuary.
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Smith, Jansen A., Daniel A. Auerbach, Karl W. Flessa, Alexander S. Flecker, and Gregory P. Dietl. "Fossil clam shells reveal unintended carbon cycling consequences of Colorado River management." ROYAL SOC, 2016. http://hdl.handle.net/10150/622496.
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Water management that alters riverine ecosystem processes has strongly influenced deltas and the people who depend on them, but a full accounting of the trade-offs is still emerging. Using palaeoecological data, we document a surprising biogeochemical consequence of water management in the Colorado River basin. Complete allocation and consumptive use of the river's flow has altered the downstream estuarine ecosystem, including the abundance and composition of the mollusc community, an important component in estuarine carbon cycling. In particular, population declines in the endemic Colorado delta clam, Mulinia coloradoensis, from 50-125 individuals m(-2) in the pre-dam era to three individualsm-2 today, have likely resulted in a reduction, on the order of 5900-15 000 tCyr(-1) (4.1-10.6 mol Cm-2 yr(-1)), in the net carbon emissions associated with molluscs. Although this reduction is large within the estuarine system, it is small in comparison with annual global carbon emissions. Nonetheless, this finding highlights the need for further research into the effects of dams, diversions and reservoirs on the biogeochemistry of deltas and estuaries worldwide, underscoring a present need for integrated water and carbon planning.
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Magobiane, Siyathemba Emmanuel. "Willingness to pay for water quality changes in the Swartkops Estuary." Thesis, Nelson Mandela Metropolitan University, 2011. http://hdl.handle.net/10948/d1011505.
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South Africa, like the rest of the world, is vulnerable to the impact of climate change and loss of biodiversity. Water pollution is one of the six global threats to freshwater biodiversity. The future health status and productivity of South Africa’s estuaries is dependent on two main factors: management and quality and quantity of freshwater inputs. South Africa has around 250 functioning estuaries along its 3000 km coastline (Hosking 2004). They play an invaluable role in ecosystem functioning and biodiversity conservation. Estuaries are amongst the richest and most productive parts of the marine environment and as such call for careful management. Some of these ecosystems are focus areas for urban an industrial development. Urbanization and industrialization pose a serious threat to these sensitive systems. Increased water pollution from domestic use, industry and agriculture affect the ecology of these estuarine, river and lake systems. A large number of South African estuaries are still in excellent or good condition, but these are mainly the very small systems. The larger systems, like the Swartkops estuary, often very important in terms of conservation value, are also often compromised in some way or other. The reasons why they are compromised include habitat destruction, artificial breaching and pollution, especially those close to urban areas. This situation is aggravated by outdated and inadequate sewage treatment plant infrastructure and unskilled operators that dispose untreated waste into these systems. Pollution into estuaries can result in the partial loss of the environmental service flows supplied by them. The result of lost environmental service flows has adverse consequences, such as diminished residential and holiday recreational appeal, as well as reduced capacity to support subsistence livelihoods. Poor water quality not only limits its utilisation value, but is also places added economic burden on society, through both the primary treatment costs and the secondary impacts on the economy. Healthy estuarine ecosystems are essential for the maintenance of biodiversity and a wide range of environmental goods and services. Without a drastic improvement in water quality management approaches and treatment technologies, the continuous deterioration in water quality will decrease benefits and increase costs affiliated with use of these water resources.The market-based system of the South African economy has to a large extent failed to account for the value of the “free” goods and services provided by the natural environment. When the true value of the natural resources is unknown, there is a risk that less financial resources and capacity are made available to manage and protect these natural resources than is efficient. To ensure that these goods are properly taken into account, they must be valued and these values incorporated in social decision making. This study uses the contingent valuation method (CVM) to establish the value of the Swartkops estuary for changes to water quality. The CVM is a non-market valuation method that is widely used in cost-benefit analysis and environmental impact assessment. The CVM establishes the economic value of the good by asking the users of an environmental good to state their willingness to pay for a hypothetical scenario to prevent, or bring about, certain changes in the current condition of the environmental good. This method is subjected to some criticism. This criticism revolves around the validity and the reliability of estimated results and the effects of various biases and errors on them. The North Oceanic and Atmospheric Administration (NOAA) Blue-Ribbon panel investigating the validity of the CVM resolved that the CVM can be used to guide social decision making, if a series of guidelines are followed. The Swartkops contingent valuation (CV) was conducted with these guidelines in mind. The results of the Swartkops CV indicate that the user population has a total willingness to pay (TWTP) of R68848 (median bid) and R203632 (mean bid) annually for the implementation of a project to improve the water quality in the Swartkops estuary. User population is an important determinant of the TWTP value. As a result, using a more broadly defined user population, TWTP per annum was calculated to be R3481987 (median bid) and R10298688 (mean bid). Management of natural resources should be informed by values that reflect efficient balances, so as to obtain the most efficient use of them (Trupie 2008). Polluted water inflows into South Africa’s estuaries are a threat to their biodiversity. Healthy estuarine ecosystems are essential for the maintenance of biodiversity and human well-being (Water Assessment Programme Report 2006: 15). As a result, this study recommends that a project be implemented by the Nelson Mandela Bay Municipality to improve water quality in the Swartkops estuary.
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Richardson, Bree Lacey. "HYDROLOGICAL AND BIOGEOCHEMICAL MECHANISMS DRIVING NITROGEN AND PHOSPHORUS RETENTION IN A FRESHWATER ESTUARY." Kent State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=kent1529269594773022.
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Chion, Clément. "An agent-based model for the sustainable management of navigation activities in the Saint Lawrence Estuary." Mémoire, École de technologie supérieure, 2011. http://espace.etsmtl.ca/879/1/CHION_Cl%C3%A9ment.pdf.
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Les gestionnaires de ressources naturelles dans les aires protégées se doivent d’encadrer les
activités humaines susceptibles de menacer la santé et/ou l’intégrité des écosystèmes à
protéger. Ces systèmes physiques où des humains interagissent avec des ressources naturelles
sont appelés systèmes socio-écologiques (SSE) et possèdent les caractéristiques de systèmes
complexes adaptatifs (p. ex. coévolution). L’investigation du SSE constitué des activités de
navigation et des baleines interagissant dans le parc marin du Saguenay–Saint-Laurent
(PMSSL) et la zone de protection marine Estuaire du Saint-Laurent au Québec, Canada, ainsi
que sa représentation sous forme d’un système multi-agents sont présentées dans cette thèse.
Le simulateur implémenté, appelé 3MTSim (pour Marine Mammal and Maritime Traffic
Simulator), est conçu pour aider les gestionnaires des aires marines protégées dans leur
objectif de réduire la fréquence et l’intensité des cooccurrences bateau-baleine dans le Saint-
Laurent et incidemment les risques de collision.
Les connaissances extraites des analyses de données (relatives aux activités de navigation à
moteur et à voile), existantes ou recueillies dans le cadre de ce projet, ont justifié de
concentrer l’effort de modélisation sur les excursions commerciales (incluant les excursions
d’observation de baleines), les navires de la marine marchande et les paquebots de croisière.
Les analyses ont permis pour la première fois de dresser un portrait complet des activités de
navigation sur l’ensemble de la région où les baleines se rassemblent en grand nombre
pendant la saison estivale. Entre autres résultats, une analyse quantitative a abouti sur une
estimation précise du temps total de navigation dans chaque écosystème marin de la région.
Cette étude a permis d’identifier les zones utilisées intensivement par les activités de
navigation, telles que l’embouchure de la rivière Saguenay et le secteur au large de Les
Escoumins.
Plusieurs campagnes d’acquisition de données menées dans le cadre de ce projet ont permis
d’identifier des facteurs (p. ex. abondance et distribution des espèces de baleines, lacunes de
gestion, décisions des compagnies et des capitaines) favorisant une dynamique collective des
« croisières aux baleines » indésirable, tant du point de vue de la conservation que de
l’expérience des visiteurs du PMSSL. La rationalité limitée a été choisie comme cadre
conceptuel pour étudier la prise de décision des capitaines, et plus généralement comprendre
la dynamique du SSE des « croisières aux baleines » au complet. L’éventail des stratégies
utilisées par les capitaines de « croisières aux baleines » a été décrit et les résultats de cette
investigation vont conduire à un ensemble de recommandations relatives à la gestion durable
de ces activités à l’intérieur et aux alentours du PMSSL.
Les résultats des investigations de terrain et de l’analyse des données sur la navigation ont
alimenté le processus de construction du modèle, incluant une représentation explicite de la
prise de décision des capitaines de « croisières aux baleines ». Les analyses ont démontré que
les navires de la marine marchande et les paquebots de croisière suivent des routes
prévisibles avec peu de variabilité. Par conséquent, une approche de modélisation complexe
basée sur le comportement des pilotes a été écartée au profit d’une approche statistique,
justifiée par la quantité importante de données historiques de grande qualité disponibles pour
ces deux composantes.
L’approche de modélisation par patrons (« pattern-oriented modelling ») s’est avérée
performante pour sélectionner un modèle valide des excursions d’observation des baleines
lorsque couplé à un modèle à l’échelle de l’individu des mouvements de baleines. Les
simulations effectuées ont confirmé que les capitaines d’excursion privilégient l’observation
de quelques rares espèces de rorquals (p. ex. baleines à bosse), boudant l’espèce la plus
abondante, à savoir le petit rorqual. Par conséquent, des simulations ont été effectuées avec
3MTSim visant à quantifier l’impact d’un changement de stratégie décisionnelle des
capitaines d’excursions, tant sur la nature de l’exposition des baleines aux bateaux (intérêt
pour la conservation) que sur le contenu des excursions (intérêt commercial). Les résultats
ont montré que des capitaines virtuels soucieux d’éviter les zones d’observation
surencombrées et/ou cherchant à augmenter la diversité des espèces observées entraînait des
gains statistiquement significatifs relativement aux aspects de conservation sans affecter les
caractéristiques importantes des excursions. Enfin, les bonnes performances du modèle des
déplacements de bateaux assurent une utilisation sécuritaire de 3MTSim comme un outil
d’aide à la décision pour la gestion, dans la mesure où ses limites sont comprises et
considérées dans l’interprétation des résultats.
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Daniels, Fahiema. "The effects of catchment management and salinity on the dominant macro-algae in the Bot River estuary." Thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/26647.
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Harvey, Alice Lindiwe. "An investigation of the pollution contribution of catchments surrounding the Knysna Estuary, with implications for stormwater management." Master's thesis, Faculty of Engineering and the Built Environment, 2019. http://hdl.handle.net/11427/31254.
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The Knysna Estuary is ranked highest in South Africa for conservation importance and is a haven for endemic marine species. The ecosystem services provided by the estuary include significant biodiversity value and amenity value for residents and tourists. The economy of Knysna is reliant on tourism, which in turn is dependent on ecosystem services. The health of the Knysna Estuary is currently threatened by poor water quality. If the water pollution can be addressed, ecosystems can be protected and significant social and economic costs of environmental degradation can be avoided. The pollution contribution of runoff from catchments to the estuary is imperfectly understood. Mitigation measures designed based on imperfect knowledge may be inappropriate or fail to address the pollution concerns. A poor understanding of the world views of stakeholders could lead to the design of socially unacceptable solutions. This study aimed to improve knowledge of the catchments surrounding the estuary, and stakeholders within these areas, to inform solutions. Surface water sampling and testing and analysis of national and municipal databases were used to assess the pollutant contribution of catchment runoff. High nutrient concentrations were conducive to eutrophic or hypertrophic conditions at most sites. Total Inorganic Nitrogen (TIN) concentrations exceeded 5 mg/ℓ at 60% of the sites. Ammonium concentrations made up a disproportionate fraction of the TIN readings, with most fractions exceeding 20%, and many exceeding 70%. Student t tests indicated that TIN concentrations at the Bongani River were significantly higher than historical data. Total Suspended Solid (TSS) concentrations at some sites were lower than historical data. E. coli spikes of over 30,000 CFU/100 mℓ were measured at nine sites in October 2018. The Bongani River catchment was identified as a significant source of elevated nutrients and E. coli. Elevated nutrients and TSS were also recorded in the effluent from the Knysna Waste Water Treatment Works (WWTW) with mean values of 36 and 24 mg/ℓ for Total Ammonia Nitrogen (TAN) and TSS respectively. A Kendall correlation analysis indicated significant positive trends in TIN and TAN, and negative trends in Soluble Reactive Phosphorus. A hydrological model was built for the Bongani Catchment. Data input to the model was obtained from site visits, literature, and a desktop study of available catchment information. The model was calibrated against observed data at two water level monitoring points. The model was used to estimate pollutant loads for large storms, and can be used to inform possible pollution mitigation strategies. Further water management challenges and pollution sources were identified through stakeholder interviews. A decision support tool was used to understand how stakeholder world views and values can inform the selection of socially acceptable solutions. Stakeholder interviews identified sewage leaks as a water management concern. This corresponds well with the elevated nutrient and E. coli concentrations measured in many catchments. Other identified pollutants were litter and TSS.
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Sutherland, Kate. "The dynamics of Larval fish and Zooplankton assemblages in the Sundays Estuary, South Africa." Thesis, Nelson Mandela Metropolitan University, 2010. http://hdl.handle.net/10948/1119.
Full textAbstract:
The larval fish and zooplankton assemblages were studied in the permanently open Sundays Estuary on the south-east coast of South Africa, using standard boat-based plankton towing methods. A total of 8174 larval and early juvenile fishes were caught, representing 12 families and 23 taxa. The Clupeidae, Gobiidae and Blenniidae were the dominant fish families. Common species included Gilchristella aestuaria, Caffrogobius gilchristi, Omobranchus woodi, Liza dumerilii, Glossogobius callidus and Myxus capensis. Estuarine resident species (Category I) predominantly in the preflexion developmental stage, dominated the system. A total of 19 zooplankton taxa were recorded. Copepoda dominated the zooplankton community. Dominant species included Pseudodiaptomus hessei, Acartia longipatella, Halicyclops sp., Mesopodopsis wooldridgei, and the larvae of Paratylodiplax edwardsii and Hymenosoma orbiculare. Mean larval fish density showed similar trends seasonally, spatially and across salinity zones, with mean zooplankton density in the Sundays Estuary. Gut content analysis of five larval fish species: Gilchristella aestuaria, Pomadasys commersonnii, Monodactylus falciformis, Myxus capensis and Rhabdosargus holubi, revealed species specific diet and prey selection. Although larval fish diet contained a variety of prey items, guts were dominated by P. hessei, chironomid larvae, Corophium triaenonyx, copepod eggs and insect larvae. Physico-chemical drivers and the interactions between these two plankton communities provide information that enables a more holistic view of the dynamics occurring in the Sundays Estuary planktonic ecosystem.
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Weston, Johanna Nadia Jean. "Quantification of nitrate sources and sinks using a water quality network in Morro Bay Estuary, California." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/634.
Full textAbstract:
Using an instrumented water quality network in Morro Bay Estuary, California from 2007 to 2010 (15 min sampling frequency), this study addressed the two objectives of constructing a nitrate budget and assessing the influence of sampling frequency on water quality parameters. These two objectives led to the submission of an original report of research (Appendix A) and a note (Appendix B) to peer-reviewed journals.
The first objective was to characterize the high spatial and temporal variation in physical parameters and nitrate concentrations and to construct a nitrate budget quantifying sources and sinks of nitrate from the ocean, streams, and groundwater, as well as biological processes in the Estuary. Morro Bay Estuary was found to be a non-eutrophic system and a mean net exporter of nitrate, 327.15 t yr-1. Fifty-four percent of the nitrate export was attributed to nitrate sources and internal biological processing. Nitrate loading from streams contributed 37 % to the export of nitrate (124.01 t yr-1), while groundwater nitrate loading supplied a conservative estimate of 46 % of the exported nitrate (153.92 t yr-1), with a neap tide enhancement of the discharge. Denitrification, Zostera marina, and benthic macroalgae assimilation of nitrate were the dominant internal biological processes for removal and retention, but were only 35% of the total nitrate budget.
The second objective was to investigate the impact of sampling frequency and sampling location on understanding dynamics in water quality by degrading a year time series of seven parameters from three water quality monitoring stations to sampling frequencies ranging from 15 minutes to 28 days. In Morro Bay Estuary, the semi-diurnal tidal cycle was the maximum component frequency driving the variability of temperature, turbidity, and dissolved oxygen concentrations. For these parameters, asymptotes were reached and sampling frequencies greater than six hours did not explain the additional variation in the parameters sampled. Whereas, salinity, turbidity, and nitrate concentrations lacked an asymptote, and decreased sampling frequencies led to increased estimated error. Sampling water quality parameters every 28 days can lead to mean annual difference of 30 – 140 % from 15 minute sample annual mean. We recommend sampling frequencies should be selected to oversample the tidal signal to at least hourly frequencies to capture diel cycles and episodic events that contribute significantly to understanding the variability in the estuarine physical and biological dynamics.
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Moreira, Miguel Alexandre Ribeiro. "Assessing the balance between biodiversity conservation and coastal and estuarine management of the Sado Estuary Natural Reserve, Portugal, using BIO-SAFE." Master's thesis, Faculdade de Ciências e Tecnologia, 2010. http://hdl.handle.net/10362/4987.
Full textAbstract:
Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova
de Lisboa para obtenção do grau de Mestre em Engenharia do Ambiente, perfil de
Engenharia EcológicaCoastal and Estuarine management is one emergent topic nowadays. Physical reconstruction and management plans are currently being executed where the major goals are flood risk reduction,ecological rehabilitation and economic development. The ecological consequences of these measures must be evaluated in a way that ensures attuning of policy goals concerning conservation of biodiversity. The estuarine systems are important for the conservation and restoration of biodiversity, since they are one of the most productive ecosystems on the planet. Recently, a novel Spreadsheet Application For Evaluation of impacts of physical reconstruction measures on BIOdiversity (i.e. BIO-SAFE) in riverine habitats has been developed (Lenders et al., 2001, De Nooij et al., 2004, De Nooij, 2006). In this study, BIO-SAFE has been adapted to the Portuguese Sado River Estuary, with the direct application on the Natural Reserve of the cited estuarine area. BIO-SAFE is a policy and legislation based assessment model that quantifies biodiversity values in riverine areas for several taxonomic groups and landscape ecological units (ecotopes) on the basis of the policy status and habitat demands of riverine characteristic species. The model uses data on presence of species and riverine landscape ecological units for different levels of spatial scale. In this study, a new version of the model was developed for the Sado Estuary Natural Reserve (RNES), called BIO-SAFE Sado. To develop the Sado version, it was necessary to adapt the three main components of the conceptual framework of BIO-SAFE. These comprise (1) a database with the relevant policy and/or legislation RNES indigenous species, (2) a specific ecotope typology for the RNES area and (3) a weighted set of policy and legislation based valuation criteria for biodiversity. In addition to these research activities, the model has been implemented in the MS Excel spreadsheet. After implementation of these three components and the programming of the different types of indices and algorithms in MS Excel, the program calculated all relevant indexes and scores. The BIOSAFE Sado model was used for two types of analysis: (a) valuations of ecotopes (potential situation)and transitions between ecotopes and (b) valuation of the actual situation. Both approaches were made on the level of species individually and taxonomic groups at two scale levels (ecotopes and levels). The taxonomic groups higher plants, birds, fish and mammals are amongst the most important taxa regarding endangered and protected biodiversity in the study area. The ecotope valuation show that the most important ecotope types regarding protected and endangered biodiversity in the RNES are the Waterlines for the aquatic ecotope types and the Dune bushes and the indigenous forestry ecotope types Pinewood and Cork oak system for the terrestrial systems. The valuation of the actual situation shows the same results for the most important taxa and ecotopes present in the RNES, which was expected since the saturation indices showed high values, indicating that most of the potential species are actually present on the area.
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Kramer, Rachel. "Towards an alternative spatial-based management approach for estuarine fisheries in South Africa, with a case study from the Sundays Estuary." Thesis, Rhodes University, 2016. http://hdl.handle.net/10962/1007.
Full textAbstract:
Estuaries are productive habitats and biologically important ecosystems which serve as juvenile nursery areas and feeding grounds for adults from a host of fish species. They are, however, threatened habitats, increasingly exposed to human disturbance and exploitation. The stocks of several South African estuary-dependent linefish species are now considered as either overexploited or collapsed. It is clear that their dependence on estuaries would warrant the inclusion of these ecosystems into marine reserve planning exercises. Since traditional management strategies (e.g. bag and size limit restrictions) have proven ineffective for estuarine fisheries, there is a need for alternative management measures, such as spatial and temporal restrictions, to ensure increased survival of juveniles and recovery of adult breeding populations. This thesis explored the potential for an ecosystem-based approach through the application of a rapid sustainability assessment technique, and a spatial-based management approach for an important fishery species, using conservation planning software. The Sundays Estuary, Eastern Cape, South Africa falls within the footprint of the Addo Elephant National Park, with a proposed expansion to include a marine protected area (MPA). However the estuaries resources were not considered during the planning of the proposed MPA. This study conducted an indicator-based sustainability assessment based on the principles of sustainable development. The results showed that present levels of exploitation, due to non-compliance and a lack of law enforcement are unsustainable. The sustainability of the Sundays Estuary had a low overall sustainability score of only 23.8%. With limited enforcement of estuarine fisheries regulations in South Africa, alternative management measures such as spatial regulations may provide a viable option forward. The sustainability of fishery resources depends on the comprehensive understanding of the fishery resource. Acoustic telemetry is a technique that has been widely adopted to infer habitat and area use patterns of fish species. The second component of this study made use of high resolution telemetry data collected on juvenile dusky kob Argyrosomus japonicus movements within the Sundays Estuary to conduct a scenario-based approach using Marxan conservation planning software. The best solution given by Marxan, in the form of a protected area for the conservation of juvenile A. japonicus in the Sundays Estuary was identified in the middle (starting 7km from the mouth) to the upper reaches (approximately 16km from the mouth) of the estuary, ultimately providing protection to tagged individuals for 61% of their time in the estuary. Although Marxan presented a best solution, the Sundays Estuary’s small size and shape, and minimal features used, was too simplistic to be included into a Marxan analysis. However, new methods and tools to analyse and plan spatial-based management options at this scale are currently being developed. Using the Sundays Estuary as a case study, a decision tree was then developed as a protocol to assist management address the challenges of effective estuarine management depending on the unique biological and socio-economic characteristics of individual estuaries in South Africa.
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Mlangeni, Moses Mbendela. "A contingent valuation of river water inflows into the Swartkops, Kariega, Mngazi and Mngazana Estuaries in the Eastern Cape." Thesis, Nelson Mandela Metropolitan University, 2007. http://hdl.handle.net/10948/569.
Full textAbstract:
Many South African estuaries are currently believed to be generating lower levels of services than they used to in the past due to substantially reduced inflow of river water, among other reasons. The basis by which river water is allocated in South Africa has had to be re-examined. Local authorities are now required to integrate into their development planning sensitivity to the ways estuaries work; the relevant legislation being the Municipal Systems Act No. 32 of 2000. Sound water resource management requires that the benefits and costs of different water allocations be compared and an optimum determined. The Contingent Valuation Method (CVM) is used in this study to estimate the benefits of changing allocations of river water into estuaries. This study builds on a CVM pilot project done at the Keurbooms Estuary in the Southern Cape in year 2000 (Du Preez, 2002). Further CVM studies were conducted at the Knysna, Groot Brak and Klein Brak estuaries (Dimopolous, 2004). The CVM is a valuation technique based on answers given to carefully formulated questions on what people are willing to pay for specified changes of freshwater inflows into estuaries. The CVM depends on there being a close correspondence between expressed answers given to hypothetical questions and voluntary exchanges in competitive markets that would be entered into if money did actually change hands. The fact that it has proved very difficult to establish this correspondence has led to CVM being subject to criticism. However, many aspects of this criticism have been addressed in the form of methods to reduce biases, and the application of the technique has grown steadily in popularity during the past 25 years. Four estuaries, the Swartkops, Kariega, Mngazi and Mngazana, were surveyed as part of this study in order to determine users’ willingness to pay (WTP) for changes in freshwater inflows. Considerable research time was devoted at the estuaries getting to know how things worked around and in the estuaries. The Swartkops estuary is a permanently open system within the Nelson Mandela Bay metropolitan area. The estuary has the third largest salt marsh in South Africa. Its banks are highly developed with residential and industrial property and it is heavily used for both recreation and subsistence fishing by locals. The Kariega estuary is located near the semi-rural town of Kenton-on-sea, between Port Elizabeth and East London. Although it is permanently open, the Kariega estuary has very low inflows of river water. It is mainly used by retired pensioners living in holiday houses at Kenton-on-sea. The Kariega is not heavily used for recreation and subsistence fishing, except during holidays and the festive season because of its proximity to other estuaries such as the Bushmans and the Kleinemond. The Mngazi and the Mngazana estuaries are located in the Wild Coast area of the Eastern Cape, in the Port St Johns Municipal district. The Mngazi is a temporarily open/closed system which does not have high botanical ratings, although it is heavily used by visitors to the well known Mngazi River Bungalows, a highly rated hotel near the mouth of the Mngazi River. The Mngazana estuary is a permanently open system renowned for its Mangrove forests and excellent fishing spots. Both the Mngazi and Mngazana estuaries are located in rural areas and are heavily used by local village residents for subsistence purposes.
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Rajkaran, Anusha. "A status assessment of mangrove forests in South Africa and the utilization of mangroves at Mngazana Estuary." Thesis, Nelson Mandela Metropolitan University, 2011. http://hdl.handle.net/10948/1547.
Full textAbstract:
In South Africa mangrove forests are located in estuaries from Kosi Bay in KwaZulu-Natal (KZN) to Nahoon Estuary in the Eastern Cape. The aims of this study were to determine the present state of mangroves in KwaZulu-Natal, by assessing the current population structure, the changes in cover over time and associated anthropogenic pressures. A second objective of this study was to determine the effect of harvesting on the population structure and sediment characteristics in the Mngazana mangrove forest. To determine if harvesting was sustainable at Mngazana Estuary; the growth and mortality rates and associated growth conditions were measured. Finally by using population modelling sustainable harvesting limits were determined by predicting the change in population structure over time. The study focussed on the KwaZulu-Natal province as a fairly recent study addressed mangrove distribution and status in the Eastern Cape Province. A historical assessment of all mangroves forests in KwaZulu-Natal (KZN) revealed that the potential threats to mangroves in South Africa include; wood harvesting, altered water flow patterns coupled with salinity changes, prolonged closed-mouth conditions and subsequent changes to the intertidal habitat. As a result mangroves were completely lost from eleven estuaries in KZN between 1982 and 1999 and a further two estuaries by 2006. Mangroves only occurred in those estuaries where the mouth was open for more than 56 percent of the time with the exception of St Lucia, where the mouth has been closed for longer but the mangrove communities have persisted because the roots of the trees were not submerged. All mangrove forests in KZN were regenerating in terms of population structure as they had reverse J-shaped population curves as well as high adult: seedling ratios. Kosi Bay and Mhlathuze Estuary were two of the larger forests that showed signs of harvesting (presence of tree or branch stumps), but the greatest threat to smaller estuaries seems to be altered water flow patterns due to freshwater abstraction in the catchments and the change of land use from natural vegetation to sugar-cane plantations. These threats affect the hydrology of estuaries and the sediment characteristics (particle size, redox, pH, salinity, temperature) of the mangrove forests. The environmental conditions under which the mangrove forests currently exist were determined for five species. Lumnitzera racemosa and Ceriops tagal exhibited a narrow range of conditions as these species are only found at Kosi Bay, while Avicennia marina, Bruguiera gymnorrhiza and Rhizophora mucronata were found to exist under a wider range of conditions. The growth rate and response to environmental conditions of the three dominant species were important to determine as these species are impacted by harvesting. Mangrove growth rates were measured at Mngazana Estuary in the Eastern Cape, the third largest mangrove forest in South Africa. Areas of this estuary where mangroves harvesting has occurred, show significant differences in sediment characteristics as well as changes in population structure in harvested compared to non harvested sites. The growth rate (in terms of height) of Avicennia marina individuals increased from seedlings (0.31 cm month-1) to adults (1.2 cm month-1), while the growth of Bruguiera gymnorrhiza stabilised from a height of 150 cm at 0.65 cm month-1. The growth of Rhizophora mucronata peaked at 0.72 cm month-1 (height 151-250 cm) and then decreased to 0.4 cm month-1 for taller individuals. Increases in diameter at breast height (DBH) ranged between 0.7 and 2.3 mm month-1 for all species. Some environmental variables were found to be important drivers of growth and mortality of individuals less then 150 cm. A decrease in sediment pH significantly increased the mortality of Avicennia marina seedlings (0-50 cm) (r = - 0.71, p<0.05) and significantly decreased the growth of Rhizophora mucronata and Bruguiera gymnorrhiza seedlings (r = -0.8, r = 0.52 – p < 0.05 respectively). At Mngazana Estuary, mortality of this species showed a positive correlation with sediment moisture content indicating that this species prefers drier conditions. The density of Rhizophora mucronata was significantly correlated to porewater temperature in Northern KZN as was the growth of adult (>300 cm) Rhizophora trees at Mngazana Estuary. Mortality of Avicennia marina individuals (51-150 cm) was related to tree density indicating intraspecific competition and self thinning. Selective harvesting of particular size classes of Rhizophora mucronata was recorded when comparing length of harvested poles (~301 cm) and the size class distribution of individuals. Taking into account the differences in growth rate for each size class for this species it will take approximately 13 years to attain a height of 390 cm which is the height at which trees are selected for harvesting at this estuary. This is 2.6 times slower than those individuals growing in Kenya. The feasibility of harvesting is dependent on the growth rate of younger size classes to replace harvested trees as well as the rate of natural recruitment feeding into the population. Different harvesting intensity scenarios tested within a matrix model framework showed that limits should be set at 5 percent trees ha-1 year-1 to maintain seedling density at > 5 000 ha-1 for R. mucronata. However harvesting of Bruguiera gymnorrhiza should be stopped due to the low density of this species at Mngazana Estuary. Harvesting of the tallest trees of Avicennia marina can be maintained at levels less than 10 percent ha-1 year-1. Effective management of mangrove forests in South African is important to maintain the current state, function and diversity of these ecosystems. Management recommendations should begin with determining the freshwater requirements of the estuaries to maintain the mouth dynamics and biotic communities and deter the harvesting of (whole) adult trees particularly those species that do not coppice. Further management is needed to ensure that forests are cleared of pollutants (plastic and industrial), and any further developments near the mangroves should be minimized.
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O'Connell, Bronwyn Anne. "Home range dynamics of spotted grunter, pomadasys commersonnii, in a South African intermittently open estuary." Thesis, Rhodes University, 2008. http://eprints.ru.ac.za/1289/.
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Regier, Peter. "Linking Organic Matter Dynamics to Management, Restoration, and Climate in the Florida Everglades." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3385.
Full textAbstract:
The Florida Everglades is a massive and highly managed subtropical wetland ecosystem, strongly influenced by anthropogenic control of freshwater distribution and highly susceptible to a changing climate, including rising sea-level and changes in temperature and rainfall. Shifting hydrologic regimes impact ecosystem function and biogeochemistry, which in turn control the sources, fate, and transport of organic matter. As a master environmental variable, it is essential to understand how organic matter dynamics will respond to changes in the balance between freshwater and saltwater associated with landscape-scale Everglades restoration efforts and climate change. The research comprising this dissertation improves current understanding of the linkages between organic matter and hydrology in the Everglades across a broad range of temporal and spatial scales. A range of research tools, including stable molecular biomarkers, water quality sensors, data synthesis and multivariate statistics were utilized. Biomarkers were used to track particulate organic matter mobilization in response to experimentally manipulated flows and provided initial evidence that sheet flow restoration can re-engineer landscape microtopography, influencing both ecosystem structure and organic matter inputs to Everglades National Park (ENP). Short-term and long-term temporal studies indicated the quantity and quality of dissolved organic carbon responds to changes in freshwater flow to marshes and mangrove forests in ENP, and that spatial patterns and trends are driven by a complex mixture of managed and natural surface water inputs (i.e., rainfall and water management inflows) as well as groundwater discharge. Application of climate scenario forecasting to relationships established between organic matter and hydrologic drivers predicted reductions in dissolved organic carbon export from ENP and changes in organic matter molecular composition. Furthermore, high-frequency measurements showed hydrologic connectivity of freshwater and estuarine organic matter pools at sub-monthly time-scales. In summary, the work presented here clearly indicates strong yet spatiotemporally complex relationships between changes in water and the sources and transport of organic carbon through the Everglades.
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Donald, Ian R. "A preliminary assessment of the hydrodynamics of the Touw River and Wilderness Lakes system with emphasis on the management of the estuary mouth." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85775.
Full textAbstract:
Thesis (MEng)--Stellenbosch University, 2013.ENGLISH ABSTRACT: The Touw River estuary and Wilderness coastal lakes is a sensitive system from a flooding and ecological viewpoint and, therefore, careful consideration is placed on the hydrodynamics and salinity levels within the system. The estuary consists of a “temporary open/closed” estuary, where during closed mouth conditions, the sand bar at the estuary mouth is artificially managed in an attempt to reduce flood water levels in the system. The reason behind this management strategy is the construction of residential property along the flood plains of the estuary and coastal lakes, which in the past, had been exposed to regular cycles of inundation during flood events. In an attempt to reduce flood water levels in all water bodies and hence reduce the risk of inundation, a management policy was formulated. The past and present management plan is to maintain the sand bar at Touw estuary mouth, during closed mouth conditions, at an elevation of between +2.1m to +2.4m MSL, based on proposals made by the CSIR in 1981. Recent flood events, after the implementation of the management policy, still occasionally result in significant inundation of residential property, which has raised concern for some interested parties over the effectiveness of the management strategy. Furthermore, a growing concern was also evident over the long term wellbeing of the system from an ecological viewpoint. Historical data shows significant changes in salinity levels since the implementation of the management strategy which could impose negative long term effects on the system. In this study, numerical models were consequently constructed and applied in order to analyse the effectiveness of the current management policy and recalculate flood water levels under a number of proposed scenarios. Long term salinity changes were also analysed in an attempt to better understand salinity propagation throughout the system, using extreme hypothetical cases. Through the analysis of the simulation results, it was concluded that flood water levels in the Touw estuary were almost completely dependent on the size of the Touw River flood and the initial height of the sand bar at the estuary mouth. Whereas, water levels in the coastal lakes are almost entirely dependent on the quantity of runoff into the lakes and their initial water levels. The current management plan, involving only artificial manipulation of the sand bar at the estuary mouth, therefore has a fairly insignificant effect on flood water levels achieved in the coastal lakes. Furthermore, it was concluded that the construction of the preparatory channel is a vitally important aspect of the current management plan and that skimming of the sand bar alone is ineffective to completely mitigate the risk of residential inundation along the banks of the Touw River. The salinity modelling study provided a first indication of the salinity characteristics within the system. It was found that the penetration of seawater into the system was less prominent as the water bodies became further removed from the ocean and that a direct relationship was evident between the volume of direct freshwater inflow to a water body and the degree of salinity variation in that specific water body. In water bodies with high volumes of direct freshwater inflow such as the Touw estuary, a large degree of salinity variation is evident. However, in water bodies with no freshwater inflow, such as Rondevlei, salinity levels remain more stable and are less likely to fluctuate.
AFRIKAANSE OPSOMMING: Uit ‘n vloed- en ekologiese oogpunt is die Touwsriviermonding en Wilderniskusmere ‘n uiters sensitiewe stelsel en daar is dus deeglike oorweging gegee aan die hidrodinamika en soutvlakke in die stelsel. Die monding bestaan uit 'n "tydelike oop / geslote" monding, en tydens geslote mondtoestande word die sandbank by die riviermond kunsmatig beheer in 'n poging om vloedwatervlakke binne die stelsel te verminder. Die rede vir hierdie strategie is omdat baie residensiële eiendomme langs die vloedvlaktes van die monding en kusmere gebou is, wat in die verlede aan 'n gereelde siklus van oorstromings blootgestel is tydens vloede. In 'n poging om vloedwatervlakke in al die watermassas te verminder, en sodoende die risiko van oorstroming te verminder, is 'n bestuursbeleid geformuleer. In beide die vorige en die huidige bestuursplanne is die sandbank in die Touwsriviermond tydens geslote mondtoestande in stand gehou op 'n hoogte van tussen 2,1 m en 2,4 m MSL, gebaseer op die voorstelle wat deur die WNNR in 1981 gemaak is. Onlangse vloede wat plaasgevind het na die implementering van die beleid, het steeds van tyd tot tyd gelei tot noemenswaardige oorstromings van residensiële eiendomme, en kommer is uitgespreek deur 'n paar belanghebbende partye oor die doeltreffendheid van die strategie vir die bestuur. Daar is verder kommer uitgespreek oor die langtermyn welstand van die stelsel uit 'n ekologiese oogpunt. Historiese data toon 'n beduidende verandering in soutvlakke sedert die implementering van die bestuurstrategie met ‘n negatiewe langtermyn uitwerking op die stelsel. In hierdie studie is daar derhalwe numeriese modelle opgestel en toegepas ten einde die doeltreffendheid van die huidige bestuur van die beleid te bepaal, asook om die vloedvlakke te herbereken en te analiseer na aanleiding van 'n aantal voorgestelde scenario's. Langtermyn soutgehalte veranderinge is ook ontleed in 'n poging om die soutgehalte verspreiding deur die hele stelsel beter te verstaan, deur gebruik te maak van uiterste hipotetiese gevalle. Deur die ontleding van die simulasie resultate, is daar tot die gevolgtrekking gekom dat vloedwatervlakke in die Touwsrivier-monding byna heeltemal afhanklik was van die grootte van die Touwsrivier vloed en die aanvanklike hoogte van die sandbank by die riviermond. Watervlakke in die kusmere is egter byna heeltemal afhanklik van die hoeveelheid afloop na die mere en die aanvanklike watervlakke. Die huidige bestuursplan, wat slegs ‘n kunsmatige manipulasie van die sandbank by die riviermond behels, het dus 'n redelik onbeduidend invloed op die vloedwatervlakke wat in die kusmere bereik is. Daar is verder tot die gevolgtrekking gekom dat die konstruksie van die voorbereidende kanaal 'n uiters belangrike aspek van die huidige bestuursplan is, en dat die afskraping van die sandbank alleen oneffektief sou wees om die risiko van residensiële oorstroming langs die oewer van die Touwsrivier uit te skakel. Die soutgehalte modelleringstudie verskaf 'n eerste aanduiding van die soutgehalte eienskappe binne die stelsel. Daar is gevind dat die penetrasie van seewater in die stelsel minder prominent was as in die watermassas verder van die see af, en dat daar 'n duidelike direkte verband is tussen die volume van die varswater wat direk invloei na 'n watermassa en die mate van soutgehalte variasie in daardie spesifieke watermassa. In watermassas waar hoë volumes varswater direk invloei soos die Touwsrivier-monding, is 'n groot mate van soutgehalte variasie sigbaar. In die watermassas waar geen varswater invloei nie, soos die Rondevlei, bly soutvlakke meer stabiel en is minder geneig om te wissel.
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DeJong, Benjamin D. "Using The Past As The Key To The Present: Informing Coastal Resource Management With Geologic Records." ScholarWorks @ UVM, 2015. http://scholarworks.uvm.edu/graddis/354.
Full textAbstract:
Rising sea levels present an ongoing threat to communities and resources around the Chesapeake Bay, east coast, USA, where tide gauges indicate that the relative rise of sea level is approximately twice the rate of average, eustatic sea-level rise. This has significantly compromised the health and viability of salt marsh habitat on the Eastern Shore during the 20th century, and the biologists who are charged with managing coastal resources in the coming decades need to understand the nature and causes of high rates of regional sea-level rise to develop suitable adaptation plans.
Dated geologic deposits and geophysical models suggest that sea-level rise is relatively high on mid-Atlantic coastlines because the land surface is subsiding due to a collapsing glacial forebulge following the Last Glacial Maximum (LGM). To fully understand this process, past sea-level indicators such as dated shoreline deposits are needed to reconstruct regional sea-level behavior in the past, but rigorous age control on geologic deposits is largely restricted to the Holocene and to marine isotope stage (MIS) 5, so the rates and timescales over which these processes operate remain unknown.
This research provides long-term paleoenvironmental records from ancient environments under east-central Chesapeake Bay to place the current sea-level threats into the context of a long geologic history of sea-level fluctuations. First, the Pleistocene geologic framework of the region is reconstructed through borehole drilling. Sediments from boreholes provided material for interpreting depositional environments, and for establishing age control for deposits, so that the entire stratigraphy was constrained both in space and time.
The geologic framework and ages indicate that Chesapeake Bay alternated between a deeply incised fluvial system and a filled estuary repeatedly in response to major climate fluctuations since at least the early Pleistocene, ~2 Ma. The ages and sedimentology indicate that the field area was submerged intermittently in a shallow estuary until nearly the end of marine isotope stage 3. Because global sea-level proxies suggest that sea level was ~40-80 meters lower than present at that time, these ages suggest that the penultimate glacial forebulge must have remained significantly lowered for nearly 100 ky following the retreat of ice. The implication of this time lag is that mid-Atlantic coastlines are still in a relatively early state of forebulge collapse, and subsidence following retreat of ice from the Last Glacial Maximum will likely continue for the foreseeable future. Ongoing subsidence will continue to exacerbate projected eustatic sea-level rise due to changing global climate, and coastal adaptation plans must remain focused on encouraging the migration of vital habitat toward higher elevations in the landscape.
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AYO-BALI, ABIODUN Emmauel. "Geochemical Analysis of the Environmental Phases of La Barra de Santiago Estuary, El Salvador." Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1556804693894507.
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Lilyea, Bruce Victor. "Stakeholder Perceptions of Sustainable Value and Water Conservation: A Case Study of Social, Environmental, and Economic Concerns in the Rookery Bay Estuary." NSUWorks, 2015. http://nsuworks.nova.edu/shss_dcar_etd/27.
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Stakeholders’ perceptions of social, environmental, and economic concerns in the Rookery Bay Estuary were examined through this research. The purpose of this study was to discover the shared value and common resolution responses for the people of the Rookery Bay area that can extend to other local environmental management scenarios. Using Stakeholder Theory, Rational Choice Theory, Symbolic Interactionism, and Systems Theory as theoretical foundation, the following research questions were considered: RQ1) What are the points of shared value of community stakeholders facing environmental management issues? RQ2) How do the perspectives of the community stakeholders toward the social, environmental, and economic issues relate to their local environmental decision-making? RQ3) What are the attitudes and behaviors toward water? Participants identified the importance of water and the natural environment on the community. Additionally, participants were aware of the social, economic, and environmental issues and noted tension between stakeholders; however, they have a limited understanding of the concept of shared value. This research illustrates the benefit of weaving concepts from various fields together to strengthen the conflict studies field.The findings and recommendations in this research offer an outline that provides a path from dispute to common value generation that leads through creating shared meanings, a shared understanding, a shared story, to shared value that is stable over time.
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Mathie, Devan M. "Assessing an In-Situ Total Algae Sensor Fluorometer for Performance in Freshwater Estuaries." Kent State University Honors College / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ksuhonors1588015130835849.
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Jones, Sarah Nichola. "A study of the population dynamics and reproductive cycle of the common cockle, Cerastoderma edule in a Cornish estuary, with respect to an ecosystem approach and a proposal for management." Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367376.
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Muller, Matthew Justin. "Linking institutional and ecological provisions for wastewater treatment discharge in a rural municipality, Eastern Cape, South Africa." Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1013048.
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The Green Drop Certification Programme, launched in 2008 alongside the Blue Drop Certification Programme, aims to provide the Department of Water Affairs with a national overview of how municipalities and their individual wastewater treatment works (WWTW) are complying with licence conditions set by the National Water Act (NWA) (No. 36 of 1998; DWAF 1998) and the Water Services Act (No. 108 of 1997; DWAF 1998). By publishing the results of each municipality’s performance, the programme aims to ensure continuous improvement in the wastewater treatment sector through public pressure. The programme has been identified by this project as a necessary linking tool between the NWA and the Water Services Act to ensure protection and sustainable use of South Africa’s natural water resources. It does this through assisting municipalities to improve their wastewater treatment operations which in theory will lead to discharged effluent that is compliant with discharge licence conditions. These discharge licences form part of the NWA’s enforcement tool of Source Directed Controls (SDC) which help a water resource meet the ecological goals set for it as part of Resource Directed Measures (RDM). The link between meeting the required SDC and achieving the RDM goals has never been empirically tested. This project aimed to determine the present ecological condition of the Uie River, a tributary of the Sundays River which the Sundays River Valley Municipality (SRVM) discharges its domestic effluent into. It then determined whether the SRVM’s WWTW was complying with the General Standard licence conditions and what the impact of the effluent on the river was through the analysis of monthly biomonitoring, water chemistry and habitat data. Lastly, the project examined the effectiveness of the Green Drop Certification Programme in bringing about change in the SRVM’s wastewater treatment sector, which previously achieved a Green Drop score of 5.6 percent. It wanted to examine the underlying assumption that a WWTW which improves its Green Drop score will be discharging a better quality effluent that will help a water resource meets the RDM goals set for it. The Kirkwood WWTW did not have a discharge licence at the time of assessment and was thus assessed under the General Standard licence conditions. It was found that the Kirkwood WWTW was not complying with the General Standard discharge licence conditions in the Uie River. This was having a negative impact on the river health, mainly through high concentrations of Total Inorganic Nitrogen (TIN-N), orthophosphate and turbidity. The SRVM should see an improvement in its Green Drop score for the Kirkwood WWTW. However, the municipality showed no implementation of necessary programmes. Implementation of these programmes would help the SRVM meet the General Standard licence conditions (part of SDC) which would help the Uie River meet the RDM goals set for it.
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D'angelis, Igor Alex Binder. "O conhecimento ecológico local como ferramenta na gestão pesqueira participativa: um estudo de caso com os marisqueiros de Livramento, Santa Rita-PB." Universidade Federal da Paraíba, 2014. http://tede.biblioteca.ufpb.br:8080/handle/tede/4551.
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One of the most significant ecosystems in coastal areas in tropical regions is the mangrove-estuary complex. Artisanal fishers are the main users of mangrove resources. In Brazil artisanal fisheries are based on species that live or spend significant portion of their life cycle in these environments. Therefore fisheries management needs to be understood as an important tool to ensure the existence of this activity while ensuring the conservation of resources and ecosystems. In doing so, this study aimed to understand the local ecological knowledge of shellfish gatherers from Livramento community and analyze the limits and possibilities of this knowledge in building a participatory management, besides highlighting the current situation of Brazil and Paraiba state in sharing of fisheries management between the State and users. It was demonstrated that Brazil has many examples of co-management, especially in the North. It lies being implemented a system that aims to include local stakeholders in the management, but is restricted to consultation and the final decisions are taken by the State. In Paraíba, the management of fisheries resources is restricted to protected areas, which do not have management plans, there is a regulated management, hindering the process of user participation. The dependence of protected areas for management of resources is a limiting factor and are not always in agreement with local realities. For this reason, it is necessary to consider new forms of management that better communicate with the political-social-environmental reality of fishing communities. While assessing the knowledge of shellfish gatherers studied, it was revealed that these fishermen have a significant ecological knowledge about the species used (Anomalocardia brasiliana) and their environment. According to the level of details given by these fishermen was possible to highlight some elements observed in an ethnoecological evaluation that aims a management which sharing occurs, not only of ruling between State and community but knowledge among fishermen and academics.
Um dos ecossistemas de maior significância encontrado nas zonas costeiras em regiões tropicais é o complexo estuário-manguezal. Os pescadores artesanais são os principais usuários dos recursos dos manguezais e no Brasil a pesca artesanal baseia-se em espécies que vivem ou passam parte significativa de seu ciclo de vida nesses ambientes. Por essa razão, a gestão pesqueira precisa ser entendida como uma importante ferramenta para garantir a existência dessa atividade, ao mesmo tempo em que garante a conservação dos recursos e ecossistemas. Nesse sentido, este trabalho visou compreender o conhecimento ecológico local dos marisqueiros da comunidade de Livramento e analisar os limites e as possibilidades deste conhecimento na construção de uma gestão participativa, além de evidenciar a atual situação do Brasil e da Paraíba no compartilhamento da gestão pesqueira marinha entre Estado e usuários. Foi demonstrado que o Brasil possui diversos exemplos de gestão compartilhada, principalmente na região Norte e encontra-se em fase de implantação de um sistema que tem o intuito de incluir os atores locais na gestão, porém se restringe a consultas e mantém as decisões finais na mão do Estado. Na Paraíba, a gestão de recursos pesqueiros está restrita à unidades de conservação, que por não possuírem planos de manejo e outros aspectos essenciais para o funcionamento dessas unidades, não há, ainda uma gestão regulamentada, prejudicando o processo de participação dos usuários. A dependência de unidades de conservação para que recursos sejam geridos é limitante e nem sempre estas condizem com realidades locais. Por essa razão, se faz necessário considerar novas formas de gestão que dialoguem melhor com a realidade político-social-ambiental das comunidades pesqueiras. Ao se avaliar o conhecimento dos marisqueiros estudados, foi possível perceber que estes pescadores são detentores de um apreciável conhecimento ecológico sobre a espécie utilizada (Anomalocardia brasiliana) e o ambiente onde é encontrada. De acordo com o nível de detalhamento dado por estes pescadores acerca de certos temas, foi possível destacar alguns elementos a serem considerados em uma avalição etnoecológica que vise uma gestão na qual ocorra o compartilhamento, não só de poder entre Estado e comunidade, mas de conhecimento entre pescadores e acadêmicos.
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Baptista, Vicente Baeta Alexandra. "Réseaux trophiques des écosystèmes intertidaux : étude par les isotopes stables et l'analyse des réseaux." Phd thesis, Université de La Rochelle, 2010. http://tel.archives-ouvertes.fr/tel-00579775.
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Cette thèse de Doctorat examine le réseau trophique estuarien lié aux herbiers à zostères, Zostera noltii et quantifie le rôle trophique des consommateurs de la macrofaune benthique, dans deux zones intertidales de l'estuaire du Mondego, à différentes périodes de 1993 à 2008. Elle s'intéresse spécifiquement (i) à l'incorporation de l'azote issu des activités humaines, en considérant l'assimilation d'azote comme un indicateur de l'eutrophication et (ii) au rôle des zostères dans le réseau trophique benthique. Six modèles ont été développés afin d'analyser les effets, (i) d'un enrichissement en nutriments, (ii) des mesures de mitigation, et (iii) d'une inondation centennale, sur les propriétés du réseau trophique benthique estuarien. La présence de Z. noltii change peu la structure du réseau trophique planctonique, soutenu en partie par la matière organique particulaire et supporte principalement des poissons comme prédateurs. Les autres consommateurs montrent une grande variabilité de signature isotopique, ce qui suggère qu'ils peuvent changer de régime alimentaire en fonction des changements de l'environnement. En revanche, les δ13C et δ15N des producteurs et consommateurs de l'estuaire du Mondego montrent très peu de variation saisonnière, malgré une saisonnalité météorologique marquée, ainsi qu'une forte variation saisonnière des paramètres de la colonne d'eau (apports en sels nutritifs et concentration en chlorophylle a). Les modèles à l'état stable montrent enfin que la structure trophique de la communauté benthique de l'estuaire du Mondego est affectée différemment par chacun des évènements particuliers étudiés.
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Sinnott, Tyler King. "Eelgrass (Zostera marina) Population Decline in Morro Bay, CA: A Meta-analysis of Herbicide Application in San Luis Obispo County and Morro Bay Watershed." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2236.
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The endemic eelgrass (Zostera marina) community of Morro Bay Estuary, located on the central coast of California, has experienced an estimated decline of 95% in occupied area (reduction of 344 acres to 20 acres) from 2008 to 2017 for reasons that are not yet definitively clear. One possible driver of degradation that has yet to be investigated is the role of herbicides from agricultural fields in the watershed that feeds into the estuary. Thus, the primary research goal of this project was to better understand temporal and spatial trends of herbicide use within the context of San Luis Obispo (SLO) County and Morro Bay Watershed by analyzing data of application by mass, area, and intensity to identify herbicides with the highest potential for local environmental pollution. California Pesticide Use Annual Summary Reports (PUASR) from the years 2000 to 2017 were used to obtain data for conducting a meta-analysis to estimate total herbicide application by weight within every township, range, and section for each of the eight selected herbicides: oxyfluorfen, glyphosate, diuron, chlorthal-dimethyl, simazine, napropamide, trifluralin, and oryzalin. A second goal was to select an analytical laboratory that would be best suited for herbicide analysis of estuary sediments to determine the presence, or lack thereof, of the eight selected herbicides. Criteria of consideration in laboratory selection included herbicides detection capabilities, detection/reporting limits, testing prices, chain of custody protocols, turnaround times, and laboratory site locations.
The meta-analysis yielded results showing high herbicide application rates in SLO County with glyphosate, oxyfluorfen, and chlorthal-dimethyl being identified as three herbicides of elevated risk for local environmental contamination due high rates of use by mass, by area, and/or intensity during the study timeframe. Additionally, Morro Bay Watershed exhibited moderate rates of herbicide application with chlorthal-dimethyl and glyphosate being of highest risk for contamination and accumulation within the estuary because of high application rates by mass, by area, and/or intensity. Finally, Environmental Micro Analysis (EMA) and Primus Group, Inc. (PrimusLabs) were identified as the top candidates for analytical laboratory testing of Morro Bay Estuary sediment samples to be obtained and tested for the selected herbicides. These laboratories provide superior analytical capabilities of the eight herbicides, impressive reporting limits or lower detection limits, competitive testing prices for detecting multiple constituents in multiple samples, robust chain of custody protocols, options for quick turnaround times, and laboratory site locations within California.
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Swan, Rachel. "An Academic Assessment of the National Performance Network and Visual Artists Network: An Internship Academic Report." ScholarWorks@UNO, 2015. http://scholarworks.uno.edu/aa_rpts/181.
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This academic report was composed at the conclusion of a 480 hour internship with the National Performance Network/Visual Artists Network (NPN/VAN), summarized in Chapter Two. This report includes NPN/VAN’s mission, history, and organizational structure within Chapter One. Chapter Three is a SWOT analysis, and Chapter Four includes a summary of best practices, highlighting NPN/VAN’s intermediary and network structure. In conclusion, a series of suggestions are offered for further consideration.
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Bonini, Nick. "Comparison of VNIR Derivative and Visible Fluorescence Spectroscopy Methods for Pigment Estimation in an Estuarine Ecosystem: Old Woman Creek, Huron, Ohio." Kent State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=kent1382838748.
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Ekouala, Landry. "Le développement durable et le secteur des pêches et de l'aquaculture au Gabon : une étude de la gestion durable des ressources halieutiques et leur écosystème dans les provinces de l'Estuaire et de l'Ogooué Maritime." Phd thesis, Université du Littoral Côte d'Opale, 2013. http://tel.archives-ouvertes.fr/tel-00840968.
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À l'échelle mondiale, la pêche maritime est caractérisée par une surexploitation des ressources disponibles dans les différentes pêcheries ayant des impacts très importants sur l'écosystème marin et côtier. Cette surpêche est facilitée par le progrès technique et par une demande de consommation en constante augmentation, notamment dans les pays développés. Pour faire face à cette évolution, des politiques de gestion durable de ces ressources halieutiques sont progressivement mises en place, allant des approches conventionnelles (gestion des stocks exploités) à l'approche écosystémique des pêches qui prône la réconciliation de l'exploitation durable et de la conservation de l'écosystème. Notre thèse aborde les conditions de développement d'une telle gestion durable de la pêche dans le cas précis des provinces de l'Estuaire et de l'Ogooué Maritime au Gabon. Le diagnostic établi met en évidence une exploitation désordonnée des ressources halieutiques et une détérioration générale de l'état des écosystèmes côtiers, nécessitant des mesures d'ajustement de la pression de pêche. Cependant, beaucoup de lacunes restent à combler (politique d'exploitation durable, formation des acteurs, évaluation des ressources et de l'écosystème, etc.) pour une meilleure compréhension et un suivi plus rigoureux des mutations qui affectent la durabilité des pêcheries et la vulnérabilité globale des écosystèmes côtiers. Dans ces deux provinces du Gabon, nous montrons que l'application de l'approche écosystémique des pêches, prenant la forme d'une gouvernance concertée dans le secteur des pêches et de l'aquaculture, apparaît comme une nécessité pour donner à ce secteur une place de choix dans ce pays.
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Sousa, Lisa Pinto de. "Model to integrate ecosystem services into the planning process." Doctoral thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/21697.
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Doutoramento em Ciências e Engenharia do AmbienteTriggered by the Millennium Ecosystem Assessment, among other seminal publications, ecosystem services research has experienced an almost exponential growth over the past two decades. Since then, ecosystem services have become widespread and the concept has been used in different disciplines, separately and in collaboration, to address complex socioecological problems. These efforts were accompanied at political level with a number of international and European initiatives, such as the creation of the Intergovernmental Platform on Biodiversity and Ecosystem Services, the adoption of the Strategic Plan for Biodiversity of the Convention on Biological Diversity, and the adoption of the EU Biodiversity Strategy. Driving the uptake of ecosystem services is the argument that its integration can lead to better environmental decision-making. Moreover, by emphasizing the ecosystems’ central role on human well-being it provides anthropocentric-oriented argumentation for biodiversity and nature conservation. This is particularly relevant for coastal regions which are complex socialecological systems with high ecological value but simultaneously under significant pressure. This challenges traditional forms of management and calls for a more integrative, adaptive, inclusive, and ecosystem-based management. Despite of the growing body of work, the actual uptake of ecosystem services into policy and decision-making processes is still limited and challenging. On this basis, and considering the constraints when putting ecosystem services into practice, this research aims to: i) develop and discuss a managementoriented approach to identify, classify and map the ecosystem services provided by a complex social-ecological system; ii) develop an in-depth study of the ecosystem services present in Ria de Aveiro coastal region, as well as the main pressures and potential impacts; iii) explore the potential of integration of the ecosystem services on spatial planning process, particularly on Estuary Programmes. Estuary Programmes were seen as a unique opportunity to investigate these issues, since they are special programmes, are focused on complex socialecological systems, and can be further explored. Though Vouga Estuary Programme was created in 2009, it has not been developed yet, which presents an opportunity for testing the proposed approach and methodologies in the future. Although it uses Ria de Aveiro costal region as case study, the lessons learned and the proposed model can be used in other social-ecological systems beyond the estuary level or Portugal. Despite of the identified biophysical, technical and management constraints, this research proved that it is possible to map multiple ecosystem services using available data, and that ecosystem services knowledge can be incorporated in spatial planning process by adapting current planning practices (including participation). As new data becomes available, ecosystem services’ assessment methods become standardized, and technical skills evolve, the proposed approach and methodologies can be gradually improved, following the adaptive management rationale. This research suggests that spatial planning processes need to bring together various disciplines from natural and social sciences, and be informed by multiple layers of information regarding the provision of ecosystem services, pressures, alternative futures and stakeholders’ preferences and concerns. Principles such as comprehensive, adaptive, inclusive, and integrative were considered key for guiding ecosystem services integration into spatial planning process. Additionally, it highlights the viability and relevance of integrating ecosystem services into the technical configuration of Estuary Programs and spatial planning processes, in general. It also demonstrates how the integration of these concepts helps to innovate and strengthen the process of environmental planning and management towards sustainability, territorial and social cohesion, responding to current societal challenges and contributing to human well-being.
Os serviços de ecossistemas têm vindo a assumir um papel central na investigação científica, observando-se um crescimento exponencial no número de publicações científicas nas últimas duas décadas. Impulsionado por um conjunto de publicações influentes, designadamente a avaliação global do Millennium Ecosystem Assessment, este conceito tem vindo a ser adotado por várias disciplinas no sentido de responder, individual ou conjuntamente, aos desafios decorrentes da complexidade dos sistemas socio-ecológicos. Paralelamente, a nível político, tem-se observado um aumento significativo de iniciativas internacionais e europeias com enfoque nos serviços de ecossistemas, como a criação da Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, a adoção do Plano Global Estratégico para a Biodiversidade, e a adoção da Estratégia Europeia para a Biodiversidade. Vários argumentos têm motivado a sua apropriação, nomeadamente a convicção de que a integração dos serviços de ecossistemas permitirá melhorar o processo de tomada de decisão no desenho e implementação das políticas ambientais, salientando o papel basilar dos ecossistemas no bem-estar humano. Estes aspetos são particularmente relevantes para as zonas costeiras, uma vez que estas são sistemas socio-ecológicos complexos caracterizados, simultaneamente, por um elevado valor ecológico e elevada vulnerabilidade. Esta circunstância desafia as práticas tradicionais de planeamento e apela a uma gestão mais integradora, adaptativa, inclusiva e fortemente baseada nos ecossistemas. Não obstante o crescente volume de investigação desenvolvido nesta área, a integração dos serviços de ecossistemas no processo de planeamento e tomada de decisão é considerada, ainda, limitada e desafiante, em particular nestes territórios de interface – as zonas costeiras. Assim, e tendo em consideração os constrangimentos da sua aplicação prática, são objetivos específicos desta investigação: i) desenvolver e discutir uma abordagem, orientada para a gestão do território, que permita identificar, classificar e mapear os serviços de ecossistemas; ii) desenvolver um estudo aprofundado dos serviços de ecossistemas presentes na Ria de Aveiro e zona costeira adjacente, bem como as principais pressões e potenciais impactos; iii) propor um modelo de integração dos serviços de ecossistemas no processo de planeamento espacial, aplicado aos Programas de Estuário. A figura de Programa de Estuário – por ser um programa de natureza especial, por incidir sobre um sistema socio-ecológico complexo, e por ainda não estar devidamente explorada – foi encarada como uma oportunidade única para investigar esta temática. Criado em 2009, o Programa de Estuário do Vouga não foi, à data, elaborado. Neste contexto real, antevê-se como uma excelente oportunidade de futuro para testar as metodologias e abordagem desenhadas ao longo desta investigação. Apesar do âmbito territorial da investigação ter incidência na Ria de Aveiro e zona costeira adjacente, a abordagem, os resultados e o modelo desenvolvido podem ser replicados noutros sistemas socio-ecológicos que vão para além dos estuários e do território nacional. A complexidade da área de estudo evidenciou constrangimentos de ordem biofísica, técnica e de gestão territorial. Através deste estudo demonstra-se que é possível, com base na informação existente, mapear múltiplos serviços de ecossistemas e incorporar este tipo de informação no processo de planeamento através da adaptação das práticas correntes (inclusivamente de participação). À medida que novos dados vão surgindo, que os métodos e técnicas vão sendo padronizados, e que as competências técnicas vão evoluindo, a abordagem e metodologias propostas podem ser gradualmente melhoradas, seguindo a lógica da gestão adaptativa. Constata-se a necessidade de o processo de planeamento envolver várias disciplinas das ciências naturais e sociais, bem como ter em consideração múltiplos tipos de informação, não só relativa aos serviços prestados pelos ecossistemas, mas também às pressões, aos cenários alternativos, e às preferências e preocupações dos atores chave. Finalmente, identificam-se quatro princípios fundamentais que devem orientar a integração dos serviços de ecossistemas no processo de planeamento e gestão territorial: holístico, adaptação, inclusão, integração. Esta investigação evidencia, de modo inequívoco, a viabilidade e relevância de integração dos serviços de ecossistemas na configuração técnica dos Programas de Estuário, e dos processos de planeamento em geral. Demonstra, ainda, o modo como a integração destes conceitos inova e fortalece o processo de planeamento ambiental e gestão do território, numa ótica de sustentabilidade, coesão territorial e social, respondendo aos atuais desafios societais e contribuindo para o bem-estar humano.
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Knudsen, Richard Ray. "A Study on the Integration of Multivariate MetOcean, Ocean Circulation, and Trajectory Modeling Data with Static Geographic Information Systems for Better Marine Resources Management and Protection During Coastal Oil Spill Response – A Case Study and Gap Analysis on Northeastern Gulf of Mexico Tidal Inlets." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5974.
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The Oil Pollution Act of 1990 requires the development of Regional and Area Contingency Plans. For more than 20 years, the State of Florida, under both the Department of Environmental Protection and the Florida Fish and Wildlife Commission, has worked closely with the U.S. Coast Guard and the National Oceanic and Atmospheric Administration to develop these plans for coastal and marine oil spill response. Current plans, developed with local, state and federal stakeholder input, use geographic information systems (GIS) data such as location and extent of sensitive ecological, wildlife, and human-use features (termed Environmental Sensitivity Index data), pre-defined protection priorities, and spatially explicit protection strategies to support decision-making by responders (termed Geographic Response Plans). However, they are long overdue for improvements that incorporate modern oceanographic modeling techniques and integrated data from coastal ocean observing systems. Better understanding of circulation in nearshore and estuarine waters, at a scale consistent with other spatial data, is especially lacking in Area Contingency Plans. This paper identifies the gaps in readily available information on the circulation-driven causes and effects missing in current oil spill contingency planning and describes a sample methodology whereby multiple coastal and ocean spatial science disciplines are used to answer questions that no single, non-integrated discipline can answer by itself. A path forward for further integration and development of more comprehensive plans to better support coastal protection in Florida is proposed. The advances made here are applicable to other coastal regions of the world.
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Bonini, Nick. "Assessing the Variability of Phytoplankton Assemblages in Old Woman Creek, Ohio." Kent State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=kent1469959717.
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Santos, SÃlvia Helena Lima dos. "AplicaÃÃo da teoria dos nÃmeros difusos em um modelo de operaÃÃo de reservatÃrio, para estudar o comportamento da vazÃo regularizada e do rendimento." Universidade Federal do CearÃ, 2008. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=1367.
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FundaÃÃo de Amparo à Pesquisa do Estado do CearÃEste trabalho trata da aplicaÃÃo da Teoria Fuzzy em balanÃo hidrolÃgico de um reservatÃrio, para avaliar sua capacidade de previsÃo, na determinaÃÃo do cÃlculo do risco de falha de sistemas compostos por este tipo de corpo hÃdrico. No desenvolvimento da pesquisa, uma metodologia, transformando as equaÃÃes do balanÃo hidrolÃgico em equaÃÃes fuzzys, foi aplicada. ParÃmetros como tempo de esvaziamento e evaporaÃÃo foram considerados como funÃÃes de pertinÃncias dando, assim, ao modelo um carÃter fuzzy em suas formulaÃÃes. A vazÃo e o rendimento foram determinados, para diferentes cenÃrios, em forma de funÃÃes de pertinÃncias, onde essas variÃveis de controle, com maior grau de pertinÃncia foram analisadas. Os resultados mostraram que a metodologia fuzzy pode se apresentar como uma importante alternativa no cÃlculo do risco de colapso de sistemas hidrolÃgicos, como tambÃm, pode, igualmente, se apresentar como uma boa alternativa na determinaÃÃo da sustentabilidade hÃdrica, em regiÃes com alto grau de vulnerabilidade como ocorre em regiÃes semi-Ãridas.
This work concerns with the application of Fuzzy Theory in the hydrologic system as a reservoir, to evaluate its forecast capacity, in the calculation of the risk of collapse of systems composed by this type of body of water. In the development of the research, a methodology, transforming the equations of the hydrologic balance, in fuzzy equations, was applied. Parameters as time of emptying and evaporation were considered as membership functions, giving, like this, to the model the fuzzy characteristic in their formulations. The flow and the income net were calculated, for different sceneries, as membership functions, where those control variables, with larger pertinence degree, were analyzed. The results showed that the methodology fuzzy could come as an important alternative in the calculation of the risk of collapse of hydrologic systems, as well as, it can, equally, come as a good alternative in the determination of the sustainability of water, in areas with high vulnerability degree, as it happens in semi-arid regions.
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Touili, Nabil. "Adaptation des zones côtières aux changements climatiques : Cadre opérationnel de renforcement de la résilience, appliqué à la gestion des risques d’inondation au niveau de l’estuaire de la Gironde, France." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLV104/document.
Full textAbstract:
Cette thèse doctorale porte sur la gestion des risques d’inondation et des capacités d’adaptation des zones côtières, notamment face au changement climatique. Le contexte actuel est tel que la vulnérabilité face aux aléas d’inondation est amplifiée par les phénomènes du changement climatique et par la forte exposition, des personnes et des biens, en zones à risques. Sous le cadre général du projet européen Theseus ’’Innovative technologies for safer European coasts in a changing climate’’, ce travail de recherche s’est, en particulier, appuyé sur une étude de cas en France : l’estuaire de la Gironde.L’objectif de ce travail est de proposer un cadre alternatif d’adaptation de la gestion des inondations, à l’égard des incertitudes liées au contexte climatique.Dans cet objectif, cette recherche est partie d’une étude d’exploration, des perceptions locales vis-à-vis des inondations, pour analyser ensuite la gestion actuelle, sous forme de combinaison entre mesures structurelles et non structurelles.La publication d’articles scientifiques, contenus dans ce rapport, cristallise l’essentiel des résultats obtenus et illustre la démarche itérative de progression, entre le recueil des données du terrain et l’analyse des concepts théoriques.Cette thèse doctorale a abouti à la proposition d’un cadre opérationnel de renforcement de la résilience appliqué à l’aménagement du territoire, aux systèmes d’alerte, aux plans d’évacuation, aux plans de continuité de fonctionnement, aux programmes d’assurance et à la gestion du post-traumaThis PhD thesis deals with the flood risk management and the adaptation capacities of coastal areas, in regard of the climate change.Currently, the flood hazard vulnerability is aggravated by both the climate change phenomenon and the huge exposure, of people and assets, in risk areas. In the general framework of Theseus european project, this research work has particularly focused on the Gironde estuary, in France, as a case study.The aim of this work is to provide an alternative framework of adaptation for the flood risk management, in regard of the climate change related uncertainties.In this order, our research is initiated by anexploratory study , of the local perception toward the flood hazard, followed by the analysis of the current flood risk management, as a set of structural and nonstructural measures.The published papers, included in this report, summarize our results and illustrate our iterative approach between the field data collection and the theoretical concepts analysis.This thesis research has led to put forward an operationnal framework to enhance the resilience applied to land use planning, warning systems and evacuation plans, business recovery plans, insurance programs and post trauma management
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Laskowski-Fauvet, Natacha. "Approche bioéconomique et gestion intégrée des zones humides." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0074/document.
Full textAbstract:
L'objet de cette thèse est de se demander comment améliorer la gestion des zones humides etdes biens/services associés. En intégrant les connaissances pluridisciplinaires aux modèles degestion, nous étudions l'économie comme un outil au service de l'Homme et de la Nature.Nous proposons d'améliorer la gestion des zones humides en combinant une approcheéconomique à une approche biologique de manière à pouvoir rendre compte de la complexitéde ces milieux dans les modèles économiques. Pour ce faire, nous basons cette thèse surl'étude des fonctions écosystémiques fournies par les zones humides, que sont les fonctionsd'habitat, de production et de régulation. La fonction d'habitat est traitée à travers laproblématique de l'accessibilité des zones humides de l'Estuaire de la Gironde aux espècespiscicoles migratrices. La fonction de production, étroitement liée à la fonction d'habitat, estétudiée à travers un modèle théorique de partage d'une zone humide entre productionpiscicole et production agricole. Enfin, nous traitons la fonction de régulation en intégrantcette fonction dans un programme d'incitation à la réduction de rejets de polluants agricoleset de restauration de zones humidesThis thesis aims at improving the management of wetlands and associated goods/services.By integrating multidisciplinary knowledge to management models, we study the economyas a tool that served Human and Nature. We propose to improve wetlands management bycombining an economic approach to a biological approach in order to express the complexityof these environments in economic models. To do so, this thesis is based on the study ofecosystem services provided by wetlands, which are the functions of habitat, production andregulation. Habitat function is studied through the issue of wetlands accessibility in theGironde estuary by migratory fish species. The production function, closely linked to habitatfunction, is studied through a theoretical model of shared wetland between fish productionand agricultural production. Finally, we address the regulation function by integrating thisfunction in a program of incentives to reduce emissions of agricultural pollutants and restorewetlands
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Jamieson, Marion Lea. "Local control over local resources habitat management in the Fraser Estuary." Thesis, 1991. http://hdl.handle.net/2429/3183.
Full textAbstract:
This thesis approaches the issue of local control over local resources from the perspective of municipal and regional government involvement in habitat conservation. Using the Fraser River estuary as a case study area, the expanding role of local governments is described in order to examine the relationship between local and senior levels of government. The objective is to assess whether redistributing power between these levels of government would improve habitat management in the estuary.
Improved habitat management is defined as a more democratic process of allocating costs and benefits associated with habitat conservation. Conventional administrative decision-making tends to exclude perspectives which are in conflict with maintenance of the existing distribution of costs and benefits. Two perspectives which have difficulty having their concerns addressed by administrations are the conservation and community perspectives, even though issues of conservation and community are at centre of public concern.
An expanded political framework for examining resource planning and management issues is needed, as the spectrum of political issues that frames policy debates is too limited to encompass the concerns that contemporary policy-makers must address. The most practical mechanisms for encouraging the introduction of new
ideas and innovations to the policy-making arena are existing institutional designs for communication among differing perspectives.
The Fraser River Estuary Management Program (FREMP) is one mechanism with the potential to act as a conduit for new ideas. It is explored from the perspective of local government involvement in its habitat management activities. FREMP is part of the complex web of institutional arrangements for habitat management in the Fraser estuary. These arrangements are described with a focus on the role of local governments.
The case study indicates that a process of developing an expanded framework for decision-making appears to be taking place in the estuary, reflecting the growing importance of both local government involvement and habitat conservation. Local councils are demanding more powerful enabling legislation in order to address local environmental concerns, and these demands raise
the issue of the optimal balance of power between local and senior levels of government. In light of the pivotal role that both municipal and regional governments can play in conserving and protecting resources through land-use regulation and planning, this thesis concludes that enhanced local government powers would facilitate the protection and enhancement of conservation values in the estuary.
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Pillay, Renelle Karen. "An integrated study of the Isipingo River and Estuary : water and sediment quality, estuary-nearshore material fluxes, anthropogenic impacts and management." Thesis, 2013. http://hdl.handle.net/10413/10130.
Full textAbstract:
The Isipingo River and Estuary system located in the province of KwaZulu-Natal, although
relatively small, has been subjected to the impacts of intense development within the
catchment. The catchment is characterized by informal and formal dwellings and intensive
industrial activities in the lower catchment and in close proximity to the estuary. Significant
modifications to the hydrology of the system has occurred as a result of the diversion of the
Umlazi River (which previously merged with the Isipingo River at the estuary mouth),
canalization of the lower portion of the Isipingo River flowing through the Prospecton
Industrial Area and the development of the Diversion Works system (to regulate flows to the
lower Isipingo River), removal of riparian vegetation, encroachment onto the river and
estuarine floodplain, and land reclamation through the infilling of wetlands all of which has
culminated in a deterioration of the functionality and health of this system. The main aspects
of this study focus on water and sediment quality, material flux between the estuary and the
sea and the management of the system. The water quality variables covered as part of this
dissertation include physical, chemical (nutrients and heavy metals) and microbiological
(faecal coliforms) components. The water quality of the river and estuary presents a risk to
human health and the concentrations of heavy metals generally exceeded the South African
Water Quality Guidelines that prescribes target levels, implying potential negative impacts to
aquatic health. The Isipingo system exhibited signs of eutrophication with phosphorus
concentrations in excess of the target level to prevent eutrophication. Excessive water
hyacinth growth was visible during most of the field surveys. A geochemical assessment of
heavy metals in surface sediments of the river and estuary was also undertaken. The results
indicate that although the presence of several metals were undetectable at certain river
sites, the concentrations of those heavy metals present increased in a longitudinal direction
from the river to the estuary. The contamination factor analysis for all metals indicated low
contamination except for selenium. The riverine sites yielded moderate enrichment by some
heavy metals in both seasons. The degree of contamination for each site with the exclusion
of selenium was low. The inclusion of selenium in the assessment raises the estuary to a
considerably contaminated status in the wet season. The analysis suggests that the
enrichment of the system by selenium is due to an anthropogenic source. The Geo-accumulation
Index places the sediment in an overall unpolluted category. The study
conducted on the net exchange of heavy metals and nutrients between the Isipingo Estuary
and the adjacent marine environment (i.e. Indian Ocean) demonstrates that significant
quantities of the suite of heavy metal analysed are exported on an annual basis while
copper, nickel and zinc are imported into the estuary. Significant quantities of ammonia and
nitrates are exported annually from the Isipingo Estuary while a net annual import of phosphorous is observed. The variation in the quantity and concentration of nutrients
exported during the seasons may be attributed to anthropogenic source. The import of
nutrients from marine sources can accumulate in the estuary and contribute to
eutrophication of the Isipingo Estuary. This study also demonstrated that although the ebb
flow has a much longer duration than the flood flow, the flood velocities observed were
generally greater than the ebb velocities. The final part of this research identifies other
environmental problems experienced in the Isipingo catchment. The following issues are
identified as directly or indirectly contributing to stress and deterioration of the water quality
of the Isipingo system: reduction in water quantity, poor water quality, moderate enriched
sediment, loss of habitat integrity, species diversity and invasive alien vegetation and
uncontrolled solid waste. A Water Quality Management Plan including management
objectives, strategies and action plans to address the direct and indirect factors influencing
the system are proposed. A water quality monitoring program is also proposed for the
Isipingo River and Estuary. The adoption and execution of the water quality management plan and monitoring program will assist in the prevention of further degradation of the system and will be a stepping stone toward improvement.Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2013.
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Slovak, Sarah. "Regional water planning and the National Estuary Program." Thesis, 2006. http://hdl.handle.net/2152/22560.
Full textAbstract:
Water availability, supply, accessibility, and quality issues are becoming urgent issues around the globe. Planning and management of water resources is both complicated and different in every state for every type of water resource. Estuaries are among the most important ecosystems in the world, in terms of their ecological and economic value. The many problems facing estuaries across the nation led to an effort by the Environmental Protection Agency (EPA) to protect these valuable resources and to characterize their conditions. The National Estuary Program (NEP) was established in 1987, under an amendment to the Clean Water Act to address estuarine issues and planning. Three NEP case studies, Galveston Bay Estuary Program, San Francisco Bay Estuary Program, and Tampa Bay Estuary Program provide insight into the functions, capacities and potential of the NEP. Estuary Programs can be located in a variety of institutional settings, and these case studies evaluate the institutional structure of the individual estuary program in the context of their state political environments. These programs provide interesting management and planning challenges, as estuaries do not conform to exact political jurisdictions, so NEP’s define their management areas according to watershed boundaries and their ecosystems in an effort to provide comprehensive estuarine planning and management. This professional report will evaluate these three case studies to determine the role of the NEP in regional water planning and estuarine management.text
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McNaney, Kevin Colin. "Swimming upstream : citizen involvement in the Fraser River Estuary Management Program (FREMP)." Thesis, 2000. http://hdl.handle.net/2429/11392.
Full textAbstract:
From the inception of the Fraser River Estuary Management Program (FREMP) in 1985, FREMP
has continually espoused a shared-decision making approach to managing this fertile and rapidly
developing estuary. While FREMP has been arguably quite successful in facilitating collaboration
and shared-decision making among the various levels of government in the region, the nongovernmental
community (including environmental and community groups, academia, industry
and the general public) has only had occasional and unsatisfactory involvement in these decision
making processes despite continued promises of greater community involvement (CI). The
"product" of this CI effort is marked by conflict with a community that is increasingly critical of the
credibility of FREMP, hostile to the decisions made by the program, and questioning of the basic
foundations of the estuary management plan (EMP).
The purpose of this paper is to evaluate the "process" of community involvement in FREMP from
1985 to 1998 (from estuary planning to implementation) through a series of interviews with
individuals who actively participated in FREMP, and through a review of the various reports
produced throughout the process. This research is approached within a framework developed for
an evaluation of citizen involvement in the land and resource management planning (LRMP)
process in British Columbia (Duffy et al., 1998).
The project concludes by recommending various policy options for FREMP's ongoing CI efforts
that accentuate clarity of process, involvement beyond "tokenism", communication and feedback,
and the provision of adequate resources. The recommendations include a spectrum of possible
future approaches to CI that range from a complete retreat from CI in FREMP's decision making
processes, to building on the lessons from the past in an effort to explore new, progressive
means of involving citizens in the management of the Fraser River estuary.
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Suzuki, Yasuko. "Piscivorous colonial waterbirds in the Columbia River estuary : demography, dietary contaminants, and management." Thesis, 2012. http://hdl.handle.net/1957/28030.
Full textAbstract:
Caspian terns (Hydroprogne caspia) and double-crested cormorants
(Phalacrocorax auritus) nest in large colonies on East Sand Island in the Columbia
River estuary, the largest known colonies for the two species in the world. Both
species of piscivorous colonial waterbirds have been identified as predators with a
significant impact on the survival of juvenile salmonids (Oncorhynchus spp.) listed
under the U.S. Endangered Species Act. To better understand and address issues
related to seabird-fisheries interactions in the Columbia River estuary, I conducted
studies related to the ecology, conservation, and management of these two species of
piscivorous waterbirds.
I evaluated the demographics and inter-colony movements of Caspian terns
belonging to the Pacific Coast metapopulation, with special emphasis on two breeding
colonies, one on East Sand Island in the Columbia River estuary and the other on
Crescent Island in the mid-Columbia River, based on re-sightings of color-banded
individuals. Apparent annual adult survival at both colonies was high, and age at first
reproduction was greater than previously reported for the species. Colony site
philopatry of breeding adults at both colonies was high; however, some individuals
prospected for breeding colonies over much of the Pacific Coast region and moved to
other colonies over distances of up to 3,000 km. Some terns from the large colony in
the Columbia River estuary responded quickly to the availability of new colony sites
as distant as 550 km from the estuary, and established successful breeding colonies
within less than a year of the new sites becoming available. The Caspian tern colony
on East Sand Island appears to be an important source colony for a number of smaller,
less productive colonies distributed over an extensive area from the Salton Sea,
California to the Copper River Delta, Alaska, an area with limited and ephemeral
nesting opportunities.
Environmental contaminants have been a conservation concern for wildlife in
the Columbia River estuary, especially species that consume fish and are therefore
likely to bioaccumulate persistent organic pollutants. I measured and compared levels
of polychlorinated biphenyls (PCBs) in eggs and chicks of Caspian terns and doublecrested
cormorants, as well as their primary prey fish types, at colonies on East Sand
Island and farther up-river. Based on differences in tern and cormorant diet
composition at the various study colonies, higher PCB levels in eggs and chicks were
associated with diets dominated by resident freshwater and estuarine fishes. PCB
levels in prey fish were positively correlated with lipid content; however, PCB levels
in the livers of chicks were negatively correlated with chick fat scores, suggesting that
chick fat reserves are a sink for ingested PCBs. Lower PCB levels in terns and
cormorants from East Sand Island compared to colonies farther up-river reflected diets
with a higher proportion of marine forage fishes at East Sand Island; marine forage
fishes had lower average levels of PCBs than their resident freshwater and estuarine
counterparts.
In order to explore non-destructive techniques for managing nesting colonies
of double-crested cormorants, I evaluated habitat enhancement and social attraction,
two techniques that have proven effective for relocating Caspian tern colonies to sites
where impacts on fish stocks of conservation concern would be minimal. Cormorants
were attracted to nest and successfully raised young at test plots on East Sand Island
and on islands in the estuary with a previous history of cormorant nesting or
unsuccessful nesting attempts. On an island with no history of cormorant nesting or
prospecting, however, no cormorants were attracted to nest. My results suggest that
attraction of nesting cormorants using these techniques is dependent on the previous
history of cormorant nesting or nesting attempts, the frequency and intensity of
disturbance by potential predators, and the presence of breeding cormorants nearby.
While habitat enhancement and social attraction have potential as methods for
redistributing nesting cormorants away from areas where fish stocks of concern are
highly susceptible to predation, successful establishment of new colonies using these
techniques will likely require a focus on sites with a history of cormorant nesting.
Findings from this dissertation raise some concerns over the management of
Caspian tern and double-crested cormorant colonies on East Sand Island in order to redistribute
parts of these colonies to alternative sites and mitigate the impact of those
piscivorous colonial waterbirds on ESA-listed salmonids. East Sand Island has
supported source colonies of piscivorous colonial waterbirds for many smaller
colonies throughout the region and is close to an abundant and relatively
uncontaminated food supply. Also, alternative colony sites that can substitute for East
Sand Island are not readily apparent, especially for double-crested cormorants.
Therefore, management of Caspian tern and double-crested cormorant colonies on
East Sand Island to benefit Columbia Basin salmonids needs to proceed cautiously and
reversibly because of the implications for the region-wide populations of these
piscivorous colonial waterbirds.Graduation date: 2012
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Copley, Gail J. "Shifts in environmental policy making discourses : the management of the St. Lucia estuary mouth." Thesis, 2009. http://hdl.handle.net/10413/388.
Full text