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1
Daeden, Jonathan. "Analyse des pressions anthropiques sur l’environnement littoral européen et français." Thesis, La Rochelle, 2015. http://www.theses.fr/2015LAROS019/document.
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La gestion et la conservation des littoraux exigent la synthèse de données géographiques sur la répartition et l'intensité des activités humaines et sur le cumul de leurs impacts sur les écosystèmes côtiers marins et terrestres. Actuellement, à l’échelle du littoral européen ou français, peu d’études offrent une vision globale des risques sur les habitats terrestres et marins. Comment s’y répartissent les pressions humaines sur la biodiversité ? Comment mieux définir le système littoral et ainsi améliorer la gestion de ce territoire ? A l’échelle européenne, à l’aide de 24 pressions anthropiques issues d’EUROSTAT sur une classification NUTS, nous avons découpé le littoral terrestre européen en bandes de 10 km jusqu’à une limite de 100 km et identifié la répartition et l’intensité relative des pressions sur les environnements côtiers. Nous avons ainsi montré que la grande majorité des pressions se situent directement sur le trait de côte et les 30 premiers kilomètres, puis diminue fortement jusqu’à la limite des 100 km. Ce découpage du littoral européen nous a aussi permis, à l’aide d’analyses factorielles des correspondances couplées à de la classification hiérarchique ascendante, de diviser les territoires littoraux en 4 groupes cohérents présentant les mêmes pressions et intensités relatives à l’échelle de l’Europe. A l’échelle française, nous avons également développé un modèle spatial pondéré par dires d’experts basé sur la géolocalisation de 15 pressions anthropiques pour 81 habitats biophysiques marins et terrestres présents sur les littoraux français métropolitains. L’information est synthétisée sous la forme de score appliqué à un maillage composé de 26000 cellules de 25 km². Cette méthode de scoring cumulative, dans un modèle additif des impacts anthropiques, nous montre les aires à risques à la fois sur le territoire marin et terrestre. Encore une fois, les zones les plus affectées par les perturbations humaines sont les plus proches du littoral. A contrario, les zones les moins affectées sont celles avec une bathymétrie forte et celles avec une élévation importante. Nous avons finalement développé un site web participatif qui comporte de la SIG intégrée pour permettre la collecte et la diffusion de l’analyse de ces pressions anthropiques sur la France métropolitaine en suivant notre modèle additif et permet à des échelles plus locales de restituer notre analyse à tout type d’utilisateur. Au final, peu de zones ne sont pas affectées par les activités humaines (0,1%) et au contraire, une fraction importante présente de très forts risques (4,8%). Les risques sont de plus en plus forts en se rapprochant du trait de côte. Ces analyses et les cartes développées sont des outils permettant de mieux comprendre les enjeux de conservation pour la mise en œuvre d’une gestion des socio-écosystèmes littoraux et permettront de mieux cibler les priorités dans la conservation de notre territoire à échelle continentale, nationale ou localeCoastal management and conservation require the synthesis of geographic data on the distribution and intensity of human activities and their combined impacts on marine and terrestrial coastal ecosystems. Currently, across the European or French coasts, few studies provide a global view of risks on terrestrial and marine habitats. How are human pressures on biodiversity distributed? How to define the littoral system and thus improve management of this territory? At the European level, using 24 human pressures from EUROSTAT across the NUTS classification, we cut the European coasts in strips of 10 km to a limit of 100 km and identified the distribution and relative intensity pressures on coastal environments. We have shown that the great majority of the pressures occurs directly on the coastline and in the first 30 kilometers, then decreases sharply to the limit of 100 km. This division of the European coasts has also allowed us to use factorial correspondence analyses coupled with a hierarchical cluster analysis to divide the coastal territories in 4 coherent groups with the same pressures and relative intensities across Europe. At the French level, we have also developed a spatial model weighted by expert opinions based on geolocation of 15 human pressures on 81 marine and terrestrial biophysical habitats present on the metropolitan French coasts. The information is synthesized in the form of impact score applied to a mesh composed of 26000 cells (25 km²). This method of cumulative anthropogenic impacts scoring in an additive model shows areas with higher risks on both the marine and land territory. Again, the most affected areas by the human disturbances are close to the coast. Conversely, the least affected areas are those with a strong bathymetry and those with a significant elevation. We finally developed a participatory website that includes integrated GIS that allows the collection and dissemination of analysis of these human pressures on France following our additive model and allows at more local scales to return our analysis from any type of user. In the end few areas are not affected by human activities (0.1%) and a rather large fraction present very high risk (4.8%). The nearer the coastline, the more the risks are high. These analyses and maps are tools that give better understanding of conservation issues for the implementation of a socio-ecosystems coastal management and that will target the priorities in the conservation of our territories at a continental, national or local scale
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Cruz, Barrón Magali de la. "Compartmentalization of class 1 integrons and IncP-1 plasmids in the Orne river (France), an aquatic ecosystem impacted by urban and industrial anthropogenic pressures." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0212/document.
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Les éléments génétiques mobiles (EGM) sont des structures génétiques fréquemment associées à la dissémination de gènes de résistance aux antibiotiques (GRA). Dans ce travail, nous avons utilisé deux EGM comme « proxies », les intégrons de classe 1 et les plasmides IncP-1, afin de mieux comprendre (i) le devenir possible des GRA une fois relargués dans un écosystème fluvial (l’Orne, France), ainsi que (ii) l’effet des pressions anthropiques sur leur persistance. À partir d'analyses de l'eau des rivières, nous avons pu montrer que les deux EGM ne se comportaient pas de la même manière. L'entrée des intégrons de classe 1 dans le système fluvial semblait être diffuse plutôt que ponctuelle, tandis que l'abondance du plasmide IncP-1 est relativement stable le long de la section de la rivière étudiée (23 km), indiquant ainsi une origine plutôt indigène. Les intrants anthropiques tels que les stations d’épuration des eaux usées ne semblent pas affecter l’abondance des EGM en raison d’un niveau trop élevé de dilution des effluents. Par ailleurs, il est intéressant de noter que les bactéries porteuses d’EGM semblaient être enrichies sur les matières en suspension, susceptibles de servir de véhicule pour amener des communautés de bactéries plus riches en EGM vers les sédiments. L'analyse de deux carottes de sédiment indique clairement que seules les couches supérieures présentent un niveau élevé de bactéries porteuses d’EGM. Ces abondances diminuent dans les couches plus profondes où seules des zones ponctuelles présentent des microréservoirs avec des abondances d’EGM plus élevées. Pour une carotte sédimentaire au moins, nous avons pu montrer que l'abondance relative d’EGM corrèle négativement la présence de polluants tel que le plomb ou certains HAPMobile genetic elements (MGEs) are genetic structures frequently associated to the dissemination of antibiotic resistance genes (ARGs). In this work, we used two of them as proxies, class 1 integrons and IncP-1 plasmids, to better understand (i) the possible fate of ARGs once released in a river ecosystem (Orne, France), as well as (ii) the effect of anthropogenic pressures on their persistence. From river water analyses, we could show that the two MGEs do not behave the same way. The entry of class 1 integrons in the river system appeared to be diffuse rather than punctual, while the abundance of IncP-1 plasmid is relatively stable along the river section studied (23 km) thus indicating a rather indigenous origin. Anthropic inputs such as wastewater treatment plant did not seem to affect the abundance of MGEs because a too high level of effluent dilution. Interestingly, MGE-bearing bacteria appeared to be enriched on suspended material, which is likely to serve as a vehicle to drive MGE-richer communities of bacteria toward the sediments. The analysis of two sediment cores clearly indicates that only the top layers displayed an elevated level of MGE-bearing bacteria. These abundances decrease in deeper layers where only localized zones display micro-reservoirs of elevated MGE abundances. For one sediment core at least, we could show that the relative abundance of MGE negatively correlates with pollutants such as lead or certain PAHs
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Radinger, Johannes. "Modelling fish dispersal in catchments affected by multiple anthropogenic pressures." Doctoral thesis, Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, 2014. http://dx.doi.org/10.18452/17067.
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Die Besiedlung von Gewässern durch Fische, ist neben abiotischen Lebensraumbedingungen auch von der Erreichbarkeit d.h. von der art-spezifischen Ausbreitungsfähigkeit sowie von Wanderhindernissen abhängig. Der erste Teil dieser Arbeit bietet die erste umfangreiche quantitative Analyse von Ausbreitungsmustern und -distanzen von Flussfischen. Aus der Fachliteratur wurden 160 empirische Datensätze aus 71 wissenschaftlichen Studien zur Ausbreitung von 62 Fischarten in Flüssen extrahiert und an leptokurse Wahrscheinlichkeits-Dichte-Funktionen (Dispersal kernel) angepasst. Es konnte bei Fischpopulationen zwischen einer stationären (ca. 2/3) und einer mobilen Komponente (ca. 1/3) unterschieden werden deren Ausbreitungsdistanzen von vier Faktoren abhängig sind: Fischlänge, Form der Schwanzflosse, Fließgewässergröße, betrachtete Zeitspanne. Der zweite Teil dieser Arbeit widmet sich dem neu entwickelten Fischausbreitungsmodell FIDIMO einem GIS-Softwareprogramm zur Modellierung und Simulation der räumlichen und zeitlichen Ausbreitungsmuster von Fischen in Flüssen unter Berücksichtigung von Wanderhindernissen. FIDIMO verknüpft konzeptionelle Überlegungen zu Ausbreitungsmodellen in verzweigten Fließgewässernetzwerken mit empirisch bestimmten leptokursen Fischausbreitungskurven unter ausschließlicher Verwendung von Free and Open Source Software. Im dritten Teil der Arbeit wurde FIDIMO zur Modellierung der Ausbreitung von 17 Fischarten angewendet um die Einflüsse von (i) Habitatqualität, (ii) Ausbreitungsfähigkeit und (iii) Fließgewässer-Fragmentierung auf die Besiedlungsmuster durch Fische zu bestimmen. Die Ergebnisse zeigen, dass die artspezifische Habitatqualität und Ausbreitungsfähigkeit die Besiedlung maßgeblich bestimmen. Dagegen wurde kein signifikanter Einfluss von Barrieren auf das Vorkommen einer Art gefunden. Über längere Zeiträume sinkt der Einfluss von Fischausbreitung auf das lokale Vorkommen einer Fischart während die Habitatqualität relativ wichtiger wird.The colonisation of rivers by fishes is directly linked to abiotic habitat conditions but often impaired by dispersal abilities of fishes and movement constraints such as barriers. The first part of this thesis provides the first comprehensive quantitative analysis of freshwater fish movement while considering fish populations consisting of differently mobile specimens. 160 empirical datasets from 71 studies on the movement of 62 riverine fish species were analysed based on refitted leptokurtic probability-density functions (dispersal kernels). A share of one third and two thirds emerged as a general pattern of the mobile and stationary component of a fish population, respectively. Moreover, four variables were identified primarily determining dispersal distances: fish length, aspect ratio of the caudal fin, river size and time. In the second part of the thesis, the novel fish dispersal model FIDIMO is introduced. FIDIMO provides a GIS-tool for predicting and simulating spatio-temporal patterns of fish dispersal in dendritic river networks considering movement barriers. The fish dispersal model FIDIMO links conceptual considerations on dispersal modelling with empirically observed leptokurtic fish movement patterns and the strengths of geographically explicit modelling in Free and Open Source GIS. In the third part of the thesis, FIDIMO was applied for modelling dispersal of 17 fish species to disentangle the effects of (i) habitat suitability, (ii) dispersal constraints and (iii) network fragmentation on the distribution of river fishes. The results show significant positive effects of both, local-scale habitat quality and species-specific dispersal ability on the distribution of river fishes, whereas no significant effect of barriers influencing the presence of a species could be found. Over longer time periods the importance of dispersal decreased in favour of habitat suitability becoming relatively more relevant in determining species'' presence.
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Besson, Marc. "Importance of metamorphosis in coral-reef fish larval recruitment facing anthropogenic pressures." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEP024/document.
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Le maintien et le renouvellement des populations de poissons coralliens dépendent en grande partie du recrutement larvaire, c’est-à-dire de l’installation des larves pélagiques dans les habitats récifaux adultes, et de leur survie après s’être métamorphosées en juvéniles. De plus en plus d’études révèlent que les changements de composition de l’eau, causés par le changement climatique et la pollution, peuvent altérer les capacités sensorielles des poissons coralliens, diminuant leurs aptitudes à localiser des habitats propices (maximisant leur croissance et diminuant leur mortalité) lors de l’installation. Cependant, les mécanismes internes à l’origine de ces phénomènes sont méconnus. Lors de cette thèse, j’ai examiné le recrutement larvaire du poisson chirurgien bagnard Acanthurus triostegus et mis en évidence que les changements écologiques, morphologiques, physiologiques et comportementaux qui s’y déroulent correspondent à une métamorphose contrôlée par les hormones thyroïdiennes (HT). J’ai ensuite analysé comment des stress d’origine anthropique, tels que l’élévation des températures de surface et la pollution par un pesticide d’origine agricole, peuvent perturber sa métamorphose. Lors de cette étape clé de leur cycle de vie, ces perturbations diminuent les taux d’HT, altérant la maturation de leurs organes sensoriels, leurs capacités sensorielles, et augmentant leur mortalité. Cette thèse est donc une analyse holistique de l’impact des perturbations anthropiques sur les processus moléculaires, et les changements histologiques, anatomiques et comportementaux du recrutement larvaire des poissons coralliens. Elle souligne l’importance du système thyroïdien, et invite à une meilleure compréhension des processus endocriniens du recrutement larvaire, dans l’optique d’une amélioration de la conservation des récifs coralliensThe persistence and sustainability of coral-reef fish populations depends on the continued larval recruitment, i.e. successful settlement by pelagic larvae into adult reef habitats and post-settlement survival through metamorphosis to a juvenile stage. There is growing evidence that changes to water conditions due to global change and waterborne pollution can impair coral-reef fish sensory abilities to locate settlement habitats that maximize growth while minimizing mortality risk. However, the inner mechanisms of such impairments remain unknown. In this thesis, I have examined the recruitment phase of the convict surgeonfish Acanthurus triostegus, and determined that the ecological, morphological, physiological and behavioral changes occurring at recruitment correspond to a metamorphosis mediated by thyroid hormones (TH). Then, I investigated whether this metamorphosis is prone to endocrine disruption under anthropogenic disturbances such as elevated sea water temperature and agricultural pesticide pollution. I demonstrated that such pressures can reduce TH levels at a critical developmental stage in coral-reef fishes, impairing their metamorphic processes such as intestine remodeling, sensory organ maturation, and sensory abilities acquisition, further increasing their mortality rates. Overall, this thesis is a holistic analysis that addresses molecular, histological, anatomical, and behavioral assays of multiple stressors affecting coral-reef fish recruitment. It indicates the importance of a proper endocrine function during coral-reef fish recruitment, highlighting the need for a better understanding of these processes for coral-reef conservation
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Lehosmaa, K. (Kaisa). "Anthropogenic impacts and restoration of boreal spring ecosystems." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526218533.
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Abstract Human activities have increasingly altered freshwater ecosystems. Land use is a major driver of habitat loss and land use-related input of nutrients and other pollutants from agriculture, forestry and urbanization have deteriorated water quality. Freshwater research has mainly focused on lakes and streams while the effects of anthropogenic stressors on groundwater-dependent ecosystems (GDEs) are poorly known. Likewise, the effectiveness of ecological restoration in mitigating human disturbance in GDEs remains understudied. In this thesis, I studied the effects of two main anthropogenic stressors – land drainage and groundwater contamination – on boreal spring ecosystems and evaluated the recovery of spring biodiversity and ecosystem functioning after habitat restoration. I applied several structural (macroinvertebrates, bryophytes, leaf-decomposing fungi and groundwater bacteria) and functional (organic matter decomposition and primary productivity) measures to provide a comprehensive insight into these issues. Both stressors modified spring ecosystems. Land drainage reduced the key ecosystem processes. Long-term monitoring of drainage-impacted springs showed a marked biodiversity loss and change of spring-dwelling bryophytes, and no signs of recovery were observed after about 20 years since the intial land drainage. Groundwater contamination, indicated by elevated nitrate and chloride concentrations, altered the structure of spring biota, reduced their taxonomic diversity and suppressed primary productivity in the most severely contaminated springs. Spring restoration improved habitat quality by reducing drainage-induced inflow of surface water, thus re-establishing groundwater-dominated hydrological conditions. Restoration increased abundance of habitat-specialist bryophytes and shifted macroinvertebrate composition towards natural conditions, despite the restoration actions being fairly recent. Anthropogenic activities can thus cause severe structural and functional degradation of spring ecosystems, and their self-recovery potential from these stressors seems low. Habitat restoration bears great promise as a cost-effective approach to mitigate drainage-induced impacts on spring ecosystems, but protection and co-management of groundwater resources are urgently needed to secure the role of springs as biodiversity hotspots in the boreal forest landscapeTiivistelmä Ihmistoiminta muuttaa yhä enemmän vesiekosysteemejä. Maankäyttö on johtanut elinympäristöjen häviämiseen, ja siihen liittyvä ravinne- ja haitta-ainekuormitus maa- ja metsätaloudesta sekä kaupunkiympäristöistä on merkittävästi huonontanut veden laatua johtaen maailmanlaajuiseen vesiluonnon monimuotoisuuden heikentymiseen. Vesiekosysteemien tutkimus on keskittynyt pääasiassa järvi- ja jokiympäristöihin, kun ihmistoiminnan vaikutukset pohjavesiriippuvaisiin ekosysteemeihin tunnetaan edelleen huonosti. Samoin kunnostusten merkitys pohjavesiriippuvaisten ekosysteemien tilan parantamiseksi on selvittämättä. Väitöskirjassani tarkastelin kahden keskeisen ihmistoiminnan – metsäojituksen ja pohjaveden laadun heikkenemisen – vaikutuksia lähde-ekosysteemeihin sekä arvioin elinympäristökunnostusten vaikutuksia niiden rakenteeseen ja toimintaan. Sovelsin työssäni rakenteellisia (pohjaeläimet, sammalet, lehtikariketta hajottavat sienet ja pohjavesibakteerit) ja toiminnallisia (eloperäisen aineksen hajoaminen ja perustuotanto) mittareita tuottamaan kattavan käsityksen tutkimuskysymyksiini. Sekä metsäojitukset että pohjaveden laadun heikkeneminen aiheuttavat muutoksia lähteiden rakenteessa ja toiminnassa. Metsäojitukset hidastavat keskeisiä ekosysteemitoimintoja ja johtavat lähdesammallajiston muutokseen ja monimuotoisuuden taantumiseen. Pohjaveden pilaantuminen, jota työssä ilmennettiin kohonneilla nitraatti- ja kloridipitoisuuksilla, heikentää lähdelajiston monimuotoisuutta, muuttaa lajikoostumusta ja johtaa perustuotannon laskuun voimakkaimmin kuormitetuissa lähteissä. Kunnostus parantaa lähde-elinympäristön laatua vähentämällä metsäojien aiheuttamaa pintavesivaikutusta palauttaen pohjavesivaltaisen hydrologisen tilan. Lähdekunnostusten myötä lähdesammaleet runsastuvat ja pohjaeläinyhteisön rakenne palautuu luonnontilaisten lähteiden kaltaiseksi, vaikka kunnostuksista on kulunut vasta muutamia vuosia. Väitöskirjan tulokset osoittavat, että ihmisen toiminta voi aiheuttaa muutoksia lähde-ekosysteemien rakenteessa ja toiminnassa ja lähteiden luontainen palautuminen häiriöstä on hidasta. Lähde-elinympäristöjen kunnostus vaikuttaa lupaavalta suojelutoimenpiteeltä metsäojitusten vaikutusten vähentämisessä, mutta lähteiden säilyttäminen monimuotoisena ja suojelullisesti arvokkaana luontotyyppinä edellyttää pohjavesivarojen hallinnan ja tilan suojelun tehostamista
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Marshall, Laura. "Statistical developments for understanding anthropogenic impacts on marine ecosystems." Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/3172.
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Over the past decades technological developments have both changed and increased human in influence on the marine environment. We now have greater potential than ever before to introduce disturbance and deplete marine resources. Two of the issues currently under public scrutiny are the exploitation of fish stocks worldwide and levels of anthropogenic noise in the marine environment. The aim of this thesis is to investigate and develop novel analyses and simulations to provide additional insight into some of the challenges facing the marine ecosystem today. These methodologies will improve the management of these risks to marine ecosystems. This thesis first addresses the issue of competition between humans and grey seals (Halichoerus grypus) for marine resources, providing compelling evidence that a substantial proportion of the sandeels consumed by grey seals in the North Sea are in fact H. lanceolatus, which is not commercially exploited, rather than the commercially important A. marinus. In addition, we present quantitative results regarding sources of bias when estimating the total biomass of sandeels consumed by grey seals. Secondly, we investigate spatially adaptive 2-dimensional smoothing to improve the prediction of both the presence and density of marine species, information that is often key in the management of marine ecosystems. Particularly, we demonstrate the benefits of such methods in the prediction of sandeel occurrence. Lastly this thesis provides a quantitative assessment of the protocols for real-time monitoring of marine mammal presence, which require that acoustic operations cease when an animal is detected within a certain distance (i.e. the "monitoring zone") of the sound source. We assess monitoring zones of different sizes with regards to their effectiveness in reducing the risks of temporary and permanent damage to the animals' hearing, and demonstrate that a monitoring zone of 2 km is generally recommendable.
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McClees, Whitney Elizabeth. "Anthropogenic Effects on the Fouling Community: Impacts of Biological Invasions and Anthropogenic Structures on Community Structure." PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3883.
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Coastal anthropogenic infrastructure has significantly modified nearshore environments. Because these structures often have a strong association with shipping as would be found in ports and harbors, they have been identified as invasion hotspots. Due to propagule pressure from shipping and recreational boating and suitable uncolonized substrate that provides a refuge from native predators, a greater number of non-native species have been found on these structures compared to nearby natural substrate. The mechanisms that limit the spread of non-native species from anthropogenic structures to natural substrate have been explored for several taxa at a species-specific level, but less so from an overall community perspective. Predation has been identified as one of the biotic interactions limiting invasion success. In addition to predation, dispersal ability may also prevent the spread of non-native species from anthropogenic structures to natural substrate.
This thesis addresses how these two mechanisms interact to limit the spread of non-native species from anthropogenic structures to natural substrate and how that alters overall community composition. I aimed to explore differences between communities inside and outside of a marina and determine the extent to which predator and dispersal limitation were structuring these communities. I used a three-factor design, deploying seven unglazed ceramic tiles per each treatment combination of 1) inside versus outside a marina in Yaquina Bay, Oregon; 2) cage keeping out predators greater than the mesh size, no cage, or partial cage; 3) fixed near the substrata (benthic) versus suspended 1 meter below the surface. I also transplanted caged, suspended tiles of either adults or recruits from inside the marina to benthic and suspended caging treatments outside of the marina. These tiles allowed me to examine predation when dispersal limitation was not a factor for the community inside the marina, i.e. what happens to both recruits and adults if they can get outside of the marina. I found that the communities inside and outside of the marina were different and the data suggest that both predation and dispersal limitation interact to limit the spread of non-native species. Additionally, I found that mesopredators that could fit through the caging may be influencing predation results and community structure.
This research addresses gaps in scientific knowledge regarding the mechanisms that prevent or facilitate the spread of non-native species. Future work could include the further exploration of mesopredation as an important factor in limiting the spread of non-native species and exploring dispersal limitation more in depth as well as broadening the geographic scope to see if the same trends hold true across bays and bioregions.
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Ma, Jia Ji Wei. "A geospatial methodology for assessing wetland vulnerability under anthropogenic pressures at a watershed scale." Diss., UMK access, 2006.
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Thesis (Ph. D.)--Dept. of Geosciences and School of Computing and Engineering. University of Missouri--Kansas City, 2006."A dissertation in geoscience and software architecture." Advisor: Wei Ji. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed Nov. 13, 2007. Includes bibliographical references (leaves 248-261). Online version of the print edition.
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Cloutier, Tammy. "Anthropogenic Impacts and Influence On African Painted Dogs (Lycaon Pictus)." Antioch University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=antioch1597420032227308.
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Hopson, Adrienne M. "Impacts of Anthropogenic Noise on Aquatic Invertebrates in Wetland Habitats." Kent State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=kent15645874111271.
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Launois, Lionel. "Impact des facteurs anthropiques sur les communautés piscicoles lentiques : vers l'élaboration d'un indice poisson." Thesis, Aix-Marseille 1, 2011. http://www.theses.fr/2011AIX10044/document.
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L’ichtyofaune est encore peu utilisée en bioindication sur les plans d’eau, alors que la demande des gestionnaires est forte, notamment dans le contexte de la mise en œuvre de la Directive Cadre Européenne sur l’Eau. L’objectif de cette thèse est d’analyser la réponse de l’ichtyofaune à diverses pressions anthropiques, afin de définir des variables biologiques de bioindication et construire un indice rendant compte de l’état écologique des lacs naturels et des retenues français. Plusieurs questions sont successivement abordées.En première analyse, les possibilités de sélection de métriques répondant à des pressions s’exerçant sur le bassin versant sont explorées par une approche typologique. L’analyse consiste à effectuer des classifications des plans d’eau, puis à établir, au sein de chaque groupe homogène d’un point de vue environnemental, des régressions linéaires entre les métriques candidates et les pressions. Les résultats montrent la pertinence de l’ichtyofaune en bioindication sur ces milieux, mais mettent en exergue des limites à cette approche typologique. Ainsi, afin de tester la possibilité de construction d’un bioindicateur commun aux lacs naturels et aux retenues, une méthode alternative dite « site spécifique » a ensuite été développée. Une modélisation statistique a été appliquée pour contrôler l’effet de l’environnement naturel sur les communautés piscicoles lacustres. Cette analyse montre que les métriques piscicoles répondant aux pressions sont différentes entre les deux types de milieux. La dernière étape, explique le développement d’un indicateur, construit sur le principe de la mesure d’un écart à la référence, en se basant sur une approche de type statistique par hindcasting. Cette méthode encore peu utilisée permet de s’affranchir de la sélection de sites de référence en France en modélisant les conditions biologiques de référence, i.e., telles qu’elles seraient en l’absence de pression anthropique. Les caractéristiques des communautés piscicoles des sites non perturbés sont ensuite comparées à celles des sites plus ou moins impactés par des pressions anthropiques. Ont été considérées ici les pressions s’exerçant à l’échelle du bassin versant et localement sur les plans d’eau. Suivant ce protocole, un indice poisson lacustre issu de la combinaison de métriques répondant conjointement à des pressions anthropiques globales et locales est proposé pour les lacs naturels et pour les retenues.Les avancées de ce travail et les perspectives sont ensuite discutées au regard du contexte européen de la gestion des milieux aquatiquesFish communities remain underused in the domain of lentic ecosystem bioindication, even though water managers need such tools in the current context of the Water Directive Framework. The objective of this thesis was to analyse the fish communities’ response to various anthropogenic pressures, in order to define the candidate biological variables in bioindication and to develop an index to evaluate the ecological status of French natural lakes and reservoirs. Several questions are raised.First of all, the means available to select fish-based metrics responding to catchment-scale anthropogenic pressures are analysed using a typological approach. This analysis consists in classifying lentic ecosystems using classifications, and then, within each homogenous group of ecosystems identified based on environmental criteria, performing linear regressions between candidate fish-based metrics and anthropogenic pressures. The results clearly show that fish communities could be used as good bioindicators for the lentic ecosystems, but they also underline the limits of typological approaches.To test how a bioindicator shared by natural lakes and reservoirs could be developed, an alternative site-specific method was subsequently developed. Statistical modeling was applied to control the natural environmental effects on lentic fish communities. This analysis shows that fish-based metrics responding to catchment-scale anthropogenic pressures differ in the two types of lentic ecosystems.The last part reports the development of an index, based on the reference condition approach, using a hindcasting statistical approach. This method, still infrequently used, enables one to sidestep the problem related to the selection of reference sites in France. Furthermore, this method allows modeling biological reference conditions, i.e. conditions without anthropogenic pressures. Fish communities’ characteristics are then compared for both undisturbed sites and sites that are more or less impacted by anthropogenic pressures. Both catchment-scale and local anthropogenic pressures were considered in this analysis. Following this protocol, a lake fish-based index resulting from the combination of metrics that respond jointly to global and local anthropogenic pressures was developed for natural lakes and reservoirs. Finally, the advances made as a result of this research and its perspectives are discussed with regards to the European context of aquatic ecosystem management
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Hedberg, Sofia. "Regional Quantification of Climatic and Anthropogenic Impacts on Streamflows in Sweden." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-269824.
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The anthropogenic impact on earth’s systems has rapidly increased since the middle of the last century and today it is hard to find a stream that is not influenced by human activities. The understanding of causes to changes is an important knowledge for future water management and planning and of that reason climatic and anthropogenic impact on streamflow changes in Sweden were explored and quantified. In the first step trends and abrupt changes in annual streamflow were detected and verified with the non- parametric Mann-Kendall’s and Pettitt’s test, all performed as moving window tests. In the second step HBV, a climatic driven rainfall-runoff model, was used to attribute the causes of the detected changes. Detection and attribution of changes were performed on several catchments in order to investigate regional patterns. On one hand using smaller window sizes, period higher number of detected positive and negative trends were found. On the other hand bigger window sizes resulted in positive trends in more than half of the catchments and almost no negative trends. The detected changes were highly dependent on the investigated time frame, due to periodicity, e.g. natural variability in streamflow. In general the anthropogenic impact on streamflow changes was smaller than changes due to temperature and streamflow. In median anthropogenic impact could explain 7% of the total change. No regional differences were found which indicated that anthropogenic impact varies more between individual catchments than following a regional pattern.Sedan mitten av förra århundradet har den antropogena påverkan på jordens system ökat kraftigt. Idag är det svårt att hitta ett vattendrag som inte är påverkat av mänsklig aktivitet. Att förstå orsakerna bakom förändringarna är en viktig kunskap för framtida vattenplanering och av denna anledning undersöktes och kvantiferades den antropogen och klimatpåverkan på flödesförändringar i svenska vattendrag. I arbetets första steg användes de Mann-Kendalls och Pettitts test för att lokalisera och verifiera förändringar i årligt vattenflöde. Alla test var icke parametriska och utfördes som ett glidande fönster. I nästa steg undersöktes orsakerna till förändringar med hjälp av HBV, en klimatdriven avrinningsmodell. Ett större antal avrinningsområden undersöktes för att upptäcka regionala mönster och skillnader. Perioder med omväxlande positiva och negativa trender upptäcktes med mindre fönsterstorlekar, medan större fönster hittade positiva trender i mer än hälften av områdena och knappt några negativa trender hittades. De detekterade förändringarna var på grund av periodicitet i årligt vattenflöde till stor grad beroende på det undersöka tidsintervallet. Generellt var den antropogena påverkan större påverkan från nederbörd och temperatur, med ett medianvärde där 7 % av den totala förändringen kunde förklaras med antropogen påverkan. Inga regionala skillnader i antropogen påverkan kunde identifieras vilket indikerar att den varierar mer mellan individuella områden än följer ett regionalt mönster.
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van, Blarcum Ronald A. "Anthropogenic Impacts as Revealed from Sediment Cores from Punderson Lake Ohio." Cleveland State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=csu1448536586.
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Hoppe-Speer, Sabine Clara-Lisa. "Response of mangroves in South Africa to anthropogenic and natural impacts." Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1012123.
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The total mangrove area cover in South Africa is 1631.7 ha, with the largest area cover in a few estuaries in the KwaZulu-Natal Province (1391.1 ha) and the remainder recorded in the Eastern Cape Province with 240.6 ha. This represents 0.05 percent of Africa‟s mangrove area cover and although small adds irreplaceable value to the biodiversity of South Africa. Mangroves are threatened by over-utilization through harvesting for firewood and building materials as well as excessive browsing and trampling by livestock. The objective of this study was to investigate the response of mangroves to different stressors from natural change as well as anthropogenic pressures. This was done by identifying pressures, measuring area cover, population structure and environmental parameters such as sediment characteristics. Mangroves in 17 estuaries along the east coast were investigated. Population structure and the area covered by mangroves in 2011/2012 were compared with data from the same area for 1999. Detailed studies were conducted in St. Lucia Estuary to investigate the response of mangroves to reduced tidal flooding; mangrove expansion at a latitudinal limit in a protected area at Nahoon Estuary was studied and the effect of cattle browsing on mangroves was measured at Nxaxo Estuary. The St. Lucia Estuary (28°S; 32°E) represented a unique study site as the mouth has been closed to the sea since 2002 and the mangrove habitats have been non-tidal. St. Lucia Estuary is both a Ramsar and World Heritage site and therefore understanding the response of mangroves to changes in the environment is important. In 2010 sediment characteristics and mangrove population structure were measured at four sites which were chosen to represent different salinity and water level conditions. The site fringing the main channel had the highest density of mangrove seedlings and saplings. The dry site had a lower density of mangroves with mostly only tall adult trees and few saplings. Mangrove tree height and density increased at sites with high sediment moisture and low surface sediment salinity. Few seedlings and saplings were found at sites with dry surface sediment and high salinity. Long term data are needed to assess the influence of mouth closure on recruitment and survival of the mangrove forest at St. Lucia Estuary; however this study has shown that sediment characteristics are unfavourable for mangrove growth at sites now characterized by a lack of tidal flooding. It is not known when exactly the mangroves were planted in Nahoon Estuary (32°S; 27° E), East London, but it is suspected that this was in the early 1970s. Avicennia marina (Forrsk.)Vierh. was planted first, followed a few years later by the planting of Bruguiera gymnorrhiza (L.) Lam. and Rhizophora mucronata (L.) among the larger A. marina trees. Surprisingly the mangrove population appears to be thriving and this study tested the hypothesis that mangroves have expanded and replaced salt marsh over a 33 year period. This study provides important information on mangroves growing at higher latitudes, where they were thought to not occur naturally due to lower annual average temperatures. It further provides insights on future scenarios of possible shifts in vegetation types due to climate change at one of the most southerly distribution sites worldwide. The expansion of mangroves was measured over a 33 year period (1978 - 2011) using past aerial photographs and Esri ArcGIS Desktop 10 software. In addition, field surveys were completed in 2011 to determine the population structure of the present mangrove forest and relate this to environmental conditions. The study showed that mangrove area cover increased linearly at a rate of 0.06 ha-1 expanding over a bare mudflat area, while the salt marsh area cover also increased (0.09 ha-1) but was found to be variable over time. The mangrove area is still small (< 2 ha) and at present no competition between mangroves and salt marsh can be deduced. Instead the area has the ability to maintain high biodiversity and biomass. Avicennia marina was the dominant mangrove species and had high recruitment (seedling density was 33 822 ± 16 364 ha-1) but only a few Bruguiera gymnorrhiza and Rhizophora mucronata individuals were found (< 10 adult trees). The site provides opportunities for studies on mangrove / salt marsh interactions in response to a changing climate at the most southern limit of mangrove distribution in Africa. This research has provided the baseline data, permanent quadrats and tagged trees to be used in future long-term monitoring of population growth and sediment characteristics. At Nxaxo Estuary (32°S; 28°E) the response of mangrove trees (Avicennia marina) to cattle browsing and trampling was investigated by using cattle exclusion plots. Exclusion plots were established by fencing in five 25 m2 quadrats and adjacent to each experimental quadrat a control quadrat (not fenced in, 25 m2) was set-up. Trees were tagged and measured annually from 2010 to 2012. Sediment salinity, pH, moisture, organic content, compaction as well as sediment particle size was also measured in each quadrat. Sediment characteristics did not vary between control and experimental plots but did show changes between the years. The mangrove trees in the cattle exclusion plots grew exponentially over a period of two years. There was a significant increase in mean plant height (5.41 ± 0.53 cm), crown volume (0.54 ± 0.01 m3) and crown diameter (7.09 ± 0.60 cm) from 2010 to 2012. Trees in the control plots had significantly lower growth (p < 0.05). There was a decrease in plant height (-0.07 ± 0.67cm1) and only small increases in crown volume (0.14 ± 0.1 m3) and crown diameter (2.03 ± 2.61 cm). The research showed that browsing on mangroves by cattle stunts growth and causes a shrubby appearance as a result of coppicing. The browsed trees were dwarfed with horizontal spreading of branches and intact foliage close to the ground while the plants in the cattle exclusion plots showed an increase in vertical growth and expansion. In the cattle exclusion plots there was a significantly higher percentage of flowering (67 percent) and fruiting (39 percent) trees in 2012 compared to the control sites where 34 percent of the plants were flowering and 5.4 percent of the plants carried immature propagules. Observations in the field also indicated that cattle had trampled a number of seedlings thus influencing mangrove survival. The study concluded that browsing changes the morphological structure of mangrove trees and reduces growth and seedling establishment. This is an additional stress that the mangroves are exposed to in rural areas where cattle are allowed to roam free. Seventeen permanently open estuaries provide habitat for mangrove forests along the former Transkei coast. This part of the Eastern Cape is mostly undeveloped and difficult to access. Mangrove area cover, species distribution, population structure and health of the mangrove habitat were compared with results from previous studies in 1982 and 1999. The mangrove Bruguiera gymnorrhiza had the densest stands and was widely distributed as it was present in 13 of the 17 estuaries. Avicennia marina was dominant in those estuaries which had the largest area cover of mangroves and was present in 10 estuaries, while Rhizophora mucronata was rare and only present in five estuaries. Anthropogenic and natural impacts were noted within the mangrove habitats in each of these estuaries. Harvesting of mangrove wood, livestock browsing and trampling and footpaths occurred in most of the estuaries (> 70 percent). It was observed that browsing on trees resulted in a clear browse-line and browsing on propagules mainly by goats resulted in reduced seedling establishment in most of the estuaries except those in protected areas. Mangroves had re-established in estuaries where they had been previously lost but mouth closure due to drought and sea storms resulted in the mass die back of mangroves in the Kobonqaba Estuary. There was a total loss of 31.5 ha in mangrove area cover in the last 30 years and this was a total reduction of 10.5 ha (11 percent) for every decade. This is high considering that the present total mangrove area cover is only 240.6 ha for all the Transkei estuaries. In this study it was concluded that the anthropogenic impacts such as livestock browsing and trampling as well as harvesting in these estuaries contributed most to the mangrove degradation as these are continuous pressures occurring over long periods and are expected to increase in future with increasing human population. Natural changes such as sea storms occur less frequently but could result in large scale destruction over shorter periods. Examples of these are mouth closure that result in mangrove mass mortality as well as strong floods which destroy forest by scouring of the banks.
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Knote, Christoph [Verfasser]. "Regional scale impacts of changing anthropogenic emissions on aerosols / Christoph Knote." Augsburg : Universität Augsburg, 2019. http://d-nb.info/124147530X/34.
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Chiziane, Hércio Issac Patrício. "Analysis of morphometric attributes of benthic nematodes as descriptors of the different ecological conditions." Master's thesis, ISA/UL, 2018. http://hdl.handle.net/10400.5/17979.
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Mestrado em Gestão e Conservação dos Recursos Naturais - Instituto Superior de Agronomia / Universidade de ÉvoraFree-living nematodes have been and are continually considered excellent bioindicators by several authors. Their high structural and functional diversity makes them more diversified and numerically dominant in aquatic habitats, with a wide distribution ranging from untouched habitats to highly polluted habitats. This fact as called the attention of many researchers who in turn motivated and promoted their use in the evaluation of the quality of water bodies. Farther, studies showed that morphometry and biomass are two important aspects to consider in ecological studies of free-living nematodes. The current study focuses on the investigation of the morphometric attributes of the free-living nematodes of the Tagus estuary (Portugal) in order to relate them to the various environmental conditions of the sediment along the estuary. Therefore, the following null hypothesis was tested: There will be no differences in the nematode morphometric parameters (length, width, L / W ratio and biomass) in the different sections of the estuary. Conclusions led to the rejection of the null hypothesis as significant differences were observed along the sections of the estuary for most of the morphometric attributes measurements taking in consideration the six most abundant genera of nematodes in the Tagus estuary (Terschellingia, Sabatieria, Daptonema, Ptycholaimellus, Viscosia and Anoplostoma). Though salinity, depth, grain size variables and organic matter were the environmental variables that were found to be more correlated with the nematode morphometric attributes variance along the estuary, nematode size and shape at investigated sections most likely reflected differences in quality and quantity of organic material and sediment size of the estuary. Most of the variability in terms of nematode morphometry along the Tagus estuary were verified for the genera Terschellingia leading to the conclusion that this genera can provide better information about the different environmental conditions of the sediment along the Tagus estuary
Os nemátodes de vida livre foram e são continuamente considerados ótimos bioindicadores por vários autores. A elevada diversidade estrutural e funcional dos nemátodes de vida livre torna-os o grupo mais diversificado e numericamente dominante em habitats aquáticos, com uma ampla distribuição que varia de habitats intocados a habitats altamente poluídos. Este fato chamou a atenção de muitos investigadores que, por sua vez, motivaram e promoveram o seu uso na avaliação da qualidade das massas de água. Além disso, estudos mostraram que a morfometria e biomassa são dois aspectos importantes a serem considerados em estudos ecológicos de nemátodes de vida livre. O corrente estudo foca-se na investigação dos atributos morfométricos dos nemátodes de vida livre do estuário do Tejo de modo a relacioná-los com as várias condições ambientais do sedimento ao longo do estuário. Para este efeito foi testada a seguinte hipótese nula: Não haverá diferenças nos parâmetros de nemátodes (comprimento, largura, relação C/L e biomassa) em diferentes secções do estuário. As conclusões levaram à rejeição da hipótese nula. Diferenças significativas foram observadas ao longo das seções do estuário para a maioria das medições dos atributos morfométricos dos seis géneros mais abundantes de nemátodes no estuário do Tejo (Terschellingia, Sabatieria, Daptonema, Ptycholaimellus, Viscosia e Anoplostoma). Embora a salinidade, profundidade, tamanho do sedimento e matéria orgânica tenham sido as variáveis ambientais mais correlacionadas com a variância dos atributos morfométricos dos nemátodes ao longo do estuário, o tamanho e a morfologia de nemátodes nas seções investigadas refletiram diferenças na qualidade e quantidade de matéria orgânica e tamanho do sedimento do estuário. A maior parte da variabilidade em termos de morfometria dos nemátodos ao longo do estuário do Tejo foi verificada para o género Terschellingia, levando à conclusão de que este género pode fornecer uma melhor informação sobre as diferentes condições ambientais do sedimento ao longo do estuário do Tejo
N/A
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Holzwarth, Ingrid [Verfasser]. "Implications of direct anthropogenic pressures on dissolved oxygen dynamics in a well-mixed estuary / Ingrid Holzwarth." Kiel : Universitätsbibliothek Kiel, 2018. http://d-nb.info/116822912X/34.
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Wnek, John P. Avery Harold W. "Anthropogenic impacts on the reproductive ecology of the diamondback terrapin, Malaclemys terrapin /." Philadelphia, Pa. : Drexel University, 2010. http://hdl.handle.net/1860/3325.
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Shaw, Kelly Ann. "Assessing Two Centuries of Anthropogenic Impacts on Silver Lake, Summit County, Ohio." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1365692437.
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Mitchell, Stephanie Bianca. "Sediment Dispersal Processes and Anthropogenic Impacts at Rex Lake, Summit County, Ohio." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1442416877.
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Yan, Na. "Dune transformations driven by vegetation change arising from environmental and anthropogenic impacts." Thesis, King's College London (University of London), 2015. http://kclpure.kcl.ac.uk/portal/en/theses/dune-transformations-driven-by-vegetation-change-arising-from-environmental-and-anthropogenic-impacts(2ecd0b0b-de76-4a3a-938d-8823b63674e9).html.
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Parabolic dunes are one of a few common aeolian landforms that are highly controlled by eco-geomorphic interactions. Parabolic dunes, on the one hand, can be developed from highly mobile dune landforms, barchans for instance, in an ameliorated vegetation condition; or on the other hand, they can be reactivated and transformed back into mobile dunes due to vegetation deterioration. The development and transformations of parabolic dunes are also highly sensitive to changes in many environmental factors such as precipitation, temperature, wind regime, as well as changes in land management and other anthropogenic factors. The eco-geomorphic interrelationships and fundamental mechanisms controlling the dune transformations, however, are incompletely understood. This study combines fieldwork investigation, remote sensing, and Cellular Automaton modelling, to explore both: 1) the dune stabilisation and barchan-to-parabolic dune transformation, as well as 2) the dune reactivation and parabolic-to-barchan dune transformation, under the influence of climatic changes (e.g., drought stress and wind energy), and human disturbance (e.g., grazing activity). Extensive suites of simulations are used to explore boundary conditions, parameter controls, and external forces on both dune transformations. The results show that the characteristics of vegetation play an essential role in the processes of dune transformations, in particular, the species (annual grasses vs. perennial shrubs) and their capabilities of withstanding wind erosion and sand burial. This study has introduced a dune stabilising index (S*) that captures the interactions between key parameters and establishes the linkage between the system controls and the geometry of a stabilising dune. The dune surface erodibility significantly influences the threshold of climatic forces that reactivates an initial vegetated parabolic dune and transforms its lobe into a mobile barchan dune with arm remnants left behind. The Extended-DECAL can be easily adapted to a different dune system to explore various scenarios under the changes in both natural and anthropogenic controls and to assist in planning judicious land-management practices.
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Maddox, Donald Shea. "Sonar imaging of bay bottom sediments and anthropogenic impacts in Galveston Bay, Texas." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4896.
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Knowledge of surface sediment distribution in Galveston Bay is important because it
allows us to better understand how the bay works and how human activities impact the
bay and its ecosystems. In this project, six areas of bay bottom were surveyed using
acoustic techniques to make maps of bay bottom types and to investigate the types and
extent of anthropogenic impacts. A total of 31 km2 was surveyed in six areas, one in
Bolivar Roads (6.1 km2), one near Redfish Bar (3.1 km2), two in East Bay (12 km2), one
southeast of the Clear Lake entrance (5.3 km2), and one in Trinity Bay (4.3 km2). Sidescan
sonars (100 kHz and 600 kHz) were used to image the bay bottom, and a chirp
sonar (2-12 kHz) was used to image subsurface sediment layers and bottom topography.
In the side-scan records, objects as small as a few meters in extent were visible, whereas
the chirp sonar records show a vertical resolution of a few tens of centimeters. The sidescan
images display strong backscatter in some areas due to coarse sediments in addition
to weak backscatter in areas of fine sediment. The bay bottom was classified using three
levels of sonar backscatter ranging from high to low. Areas of differing sonar
backscatter intensity were sampled with cores and grab-samples. High backscatter
corresponded to coarse shell debris and oyster reefs, medium backscatter corresponded to a sand-silt-shell mixture, and low backscatter corresponded to silty loam. Chirp sonar
records were classified as one of nine different bottom reflection types based on changes
in amplitude and stratigraphy. Parallel, layered sediments are seen filling the bay valley
and resting atop a sharp contact at which the acoustic signal fades out. Along the flanks
of the valley fill the acoustic response revealed an absent or weakly laminated
stratigraphy, whereas areas of high oyster productivity produced mounds, strong surface
returns, and strong, shallow subsurface reflectors surrounding current oyster reefs.
Anthropogenic features imaged with the sonar included sediment disruptions, such as the
ship channels, dredge holes, gouges, and trawl marks, as well as debris, such as
submerged boats, pipes, and unidentified objects.
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Nedelec, Sophie. "Impacts of anthropogenic noise on behaviour, development and fitness of fishes and invertebrates." Thesis, Paris, EPHE, 2015. http://www.theses.fr/2015EPHE3037/document.
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Dans la première partie de ma thèse, je fournis un programme informatique qui permet aux utilisateurs de déterminer dans quelles circonstances ils doivent mesurer le mouvement des particules. J’explique comment ces mesures peuvent être effectuées et fournissent un programme pour analyser ce type de données. La partie principale de ma thèse comprend des expériences portant sur l'impact de l'exposition répétée au bruit du trafic, la source anthropique la plus courante de bruit dans l'environnement marin, sur les poissons et les invertébrés pendant leur développement. Je démontre qu’une variété de comportements a été touchée par le bruit. J’ai aussi trouvé que le bruit prévisible peut conduire à des impacts différents sur le développement par rapport au bruit imprévisible, mais que certaines espèces de poissons peuvent être en mesure de s'habituer au bruit du trafic, tandis que d'autres non. En outre, je trouve que le développement et la survie des limaces de mer peuvent être impactés négativement par le bruit des bateaux. Les poissons et les invertébrés constituent une source de nourriture vitale pour des millions de personnes et constituent des liens essentiels dans de nombreux réseaux trophiques. L'étude de leur comportement, de développement et de remise en forme peut nous donner un aperçu des impacts de la population et le niveau de bruit de la communauté qui sont pertinents pour la survie des espèces et l'évolution. Le développement de certaines des nouvelles idées et techniques abordées dans cette thèse nous permettra de faire progresser ce domaine vital de la rechercheAs the first part of my thesis, I provide a computer program which allows users to determine under what circumstances they should measure particle motion; I explain how these measurements can be made and provide a program for analysing this type of data. The main part of my thesis comprises experiments investigating the impact of repeated exposure to traffic noise, the most common anthropogenic source of noise in the marine environment, on fishes and invertebrates during development. In all three chapters involving experiments on fish in tanks and in the field, I found that a variety of behaviours were impacted by traffic noise playback. I also found that predictable noise can lead to different impacts on development compared to unpredictable noise, but that some species of fish may be able to habituate to traffic noise, while others suffer lower survival. Further, I found that the development and survival of seahares can be negatively impacted by traffic-noise playback. Fishes and invertebrates provide a vital food source to millions of people and form crucial links in many food webs; studying their behaviour, development and fitness can give us an insight into population and community level impacts of noise that are relevant to species survival and evolution. Developing some of the novel ideas and techniques discussed in this thesis will enable us to advance this vital area of research
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Nedelec, Sophie Louise. "Impacts of anthropogenic noise on behaviour, development and fitness of fishes and invertebrates." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.685555.
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Some anthropogenic noise is now considered pollution. Evidence is building that noise from human activities such as transportation, construction and exploration can impact behaviour and physiology in a broad range of taxa . However, relatively little research has considered effects on development or directly assessed fitness consequences, particularly with respect to repeated or chronic noise. All fishes and many invertebrates use underwater sound for processes such as orientation and communication, and are thus vulnerable to anthropogenic noise pollution. Fishes and invertebrates detect the particle motion component of sound; this component has. been neglected, but must be understood alongside acoustic pressure if the potential impacts of noise are to be fully understood. As the first part of my thesis (chapter two), I provide a computer program which allows users to determine under what circumstances they should measure particle motion; I explain how these measurements can be made and provide a program for analysing this type of data. The main part of my thesis comprises experiments investigating the impact of repeated exposure to traffic noise, the most common anthropogenic source of noise in the marine environment, on fishes and invertebrates during development. In all three chapters involving experiments on fish in tanks and in the field, I found that a variety of behaviours were impacted by traffic noise playback. I also found that predictable noise can lead to different impacts on development from unpredictable noise, but that some species of fish may be able to habituate to traffic noise, while others suffer lower survival. Further, I found that the development and survival of sea hares (Stylocheilus striatus) can be negatively impacted by traffic-noise playback. Fishes 'and invertebrates provide a vital food source to millions of people and form crucial links in many food webs; studying their behaviour, development and fitness can give us an insight into population and community level impacts of noise that are relevant to species survival and evolution. Developing some of the novel ideas and techniques discussed in this thesis will enable us to advance this vital area of research.
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Eilers, Silke [Verfasser], Helmut [Akademischer Betreuer] Hillebrand, and Thomas [Akademischer Betreuer] Brey. "Analysis and assessment of cumulative effects of anthropogenic pressures on ecosystem components / Silke Eilers ; Helmut Hillebrand, Thomas Brey." Oldenburg : BIS der Universität Oldenburg, 2021. http://d-nb.info/123414896X/34.
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Begg, Fiona H. "Anthropogenic '1'4C in the natural (aquatic) environment." Thesis, University of Glasgow, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300458.
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Freitas, Luís Guilherme Pereira Antunes. "Planeamento de restauro fluvial do Rio Alcoa." Master's thesis, ISA/UTL, 2012. http://hdl.handle.net/10400.5/5321.
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Mestrado em Engenharia do Ambiente - Instituto Superior de AgronomiaThe European Union established a framework for Community action in the field of water policy. Considering the need for the natural resources protection and conservation, the Water Framework Directive 2000/60/EC Directive was adopted, involving the efforts of all Member States in the task of achieving good status for all waters, in which the aim of achieving good ecological state for natural ecosystems can be included. Within this context, the main objectives of this study are: the characterisation and quantification of the degradation degree in the fluvial ecosystem of the Alcoa river drainage basin, and to that end it was used the Predictive Ecological State methodology; and planning restoration actions for the most degraded stretches of the river system which deteriorate under the effect of human actions. Based on the results obtained, a Map of River Corridor Conservation Status was developed for the Alcoa river catchment area with the intend of revealing the degree of degradation of the river streams, and a Map of River Restoration Planning was developed which summarizes the restoration actions to be implement in the drainage basin.
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Md, Noar Nor. "Wave impacts on rectangular structures." Thesis, Brunel University, 2012. http://bura.brunel.ac.uk/handle/2438/6609.
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There is a good deal of uncertainty and sensitivity in the results for wave impact. In a practical situation, many parameters such as the wave climate will not be known with any accuracy especially the frequency and severity of wave breaking. Even if the wave spectrum is known, this is usually recorded offshore, requiring same sort of (linear) transfer function to estimate the wave climate at the seawall. What is more, the higher spectral moments will generally be unknown. Wave breaking, according to linear wave theory, is known to depend on the wave spectrum, see Srokosz (1986) and Greenhow (1989). Not only is the wave climate unknown, but the aeration of the water will also be subject to uncertainty. This affects rather dramatically the speed of sound in the water/bubble mixture and hence the value of the acoustic pressure that acts as a maximum cutoff for pressure calculated by any incompressible model. The results are also highly sensitive to the angle of alignment of the wave front and seawall. Here we consider the worst case scenario of perfect alignment. Given the above, it seems sensible to exploit the simple pressure impulse model used in this thesis. Thus Cooker (1990) proposed using the pressure impulse P(x, y) that is the time integral of the pressure over the duration of the impact. This results in a simplified, but much more stable, model of wave impact on the coastal structures, and forms the basis of this thesis, as follows: Chapter 1 is an overview about this topic, a brief summary of the work which will follow and a summary of the contribution of this thesis. Chapter 2 gives a literature review of wave impact, theoretically and experimentally. The topics covered include total impulse, moment impulse and overtopping. A summary of the present state of the theory and Cooker’s model is also presented in Chapter 2. In Chapter 3 and Chapter 4, we extend the work of Greenhow (2006). He studied the berm and ditch problems, see Chapter 3, and the missing block problem in Chapter 4, and solved the problems by using a basis function method. I solve these problems in nondimensionlised variables by using a hybrid collocation method in Chapter 3 and by using the same method as Greenhow (2006) in Chapter 4. The works are extended by calculating the total impulse and moment impulse, and the maximum pressure arising from the wave impact for each problem. These quantities will be very helpful from a practical point of view for engineers and designers of seawalls. The mathematical equations governing the fluid motion and its boundary conditions are presented. The deck problem together with the mathematical formulation and boundary conditions for the problem is presented in Chapters 5 and 6 by using a hybrid collocation method. For this case, the basis function method fails due to hyperbolic terms in these formulations growing exponentially. The formulations also include a secular term, not present in Cooker’s formulation. For Chapter 5, the wave hits the wall in a horizontal direction and for Chapter 6, the wave hits beneath the deck in a vertical direction. These problems are important for offshore structures where providing adequate freeboard for decks contributes very significantly to the cost of the structure. Chapter 7 looks at what happens when we have a vertical baffle. The mathematical formulation and the boundary conditions for four cases of baffles which have different positions are presented in this chapter. We use a basis function method to solve the mathematical formulation, and total impulse and moment impulse are investigated for each problem. These problems are not, perhaps, very relevant to coastal structures. However, they are pertinent to wave impacts in sloshing tanks where baffles are used to detune the natural tank frequencies away from environmental driving frequencies (e.g ship roll due to wave action) and to damp the oscillations by shedding vortices. They also provide useful information for the design of oscillating water column wave energy devices. Finally, conclusions from the research and recommendations for future work are presented in Chapter 8.
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Sarker, Zafar Waziha. "The Impacts of Stakeholder Pressures on Workplace Compliance in the Bangladeshi Apparel Industry." Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1574780270227769.
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Radinger, Johannes [Verfasser], Werner [Akademischer Betreuer] Kloas, Christian [Akademischer Betreuer] Wolter, and Andreas [Akademischer Betreuer] Melcher. "Modelling fish dispersal in catchments affected by multiple anthropogenic pressures / Johannes Radinger. Gutachter: Werner Kloas ; Christian Wolter ; Andreas Melcher." Berlin : Lebenswissenschaftliche Fakultät, 2014. http://d-nb.info/1063014131/34.
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Amisah, Stephen. "Impacts of anthropogenic activities on the fisheries of the Don, Rother and Dearne catchments." Thesis, University of Hull, 1998. http://hydra.hull.ac.uk/resources/hull:3797.
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Human uses and abuses of rivers have grown and diversified over the last few centuries with increasing urban development. With increasing population growth, there has been increasing demand for the use of rivers to satisfy a diverse range of human needs including solid waste disposal and the discharge of industrial, sewage and mining effluents. Rivers have been abstracted for agricultural and potable water supply and river channels have been modified for navigation, flood defences and hydro-electric power generation. These modifications to the river system disrupt the fabric of the aquatic ecosystem and diminish its integrity, affecting equally the capacity of fish and other organisms to survive. Fish depend on undamaged interactive pathways to enhance their survival, growth and recruitment.The Don, Rother and Dearne catchment in South Yorkshire and North East Derbyshire has suffered from a legacy of pollution and land contamination that dates back to the Industrial Revolution. These rivers have been grossly polluted from industrial, sewage, and mining effluents and from the disposal of solid wastes in the catchment. Much of the lengths of these rivers were fishless into the mid 1980s.Fish populations in the catchment remain low and species diversity is poor at most locations in the Don sub-catchment. Brown trout and coarse fish species are present in the Don catchment, with the salmonid populations confined to the upper reaches. Most tributaries of the River Don provide brown trout recruits to the main rivers but poor water quality and degraded habitats have prevented the successful colonisation of the waters by the species. Coarse fish, where present, were found at the middle and lower reaches of the river.Fish populations and species diversity in the River Dearne are generally poor due to serious water quality problems. Limited numbers of brown trout and coarse fish were found at few locations in the catchment, reflecting the widespread nature of poor water and habitat quality. The sub-catchment receives diverse discharges from sewage, industry and abandoned mines. This is exacerbated by various pollution incidents, the causes of some of which remain unidentified.The River Rother has low fish population densities, and many stretches of the river are fishless due mainly to poor water quality and lack of suitable habitats. Some tributaries of the River Rother, particularly the River Hipper, Redleadmill Brook and Brookside Beck hold considerable numbers of brown trout. The Rother sub-catchment also receives sewage, industrial and mine effluents which impact on the water quality.The benthic macroinvertebrate fauna of the sites studied were mainly pollution-tolerant taxa with low species diversity reflecting poor water quality. Heavy metal levels were generally low and declining which, possibly, relate to the decline in steel and coal industry in the catchment.A concerted programme to improve effluent discharges from major sewage treatment works and industries serving the catchment area coupled with a decline in the coal, steel and manufacturing industries has resulted in marked improvements in water quality of the rivers. Reductions in ammonia and BOD levels have been achieved since 1991 due mainly to improvements to sewage treatment works. As a consequence the fisheries of the rivers have shown some evidence of recovery. Unfortunately these improvements are localised and the fish populations suffer periodic setbacks because of isolated pollution incidents.Despite considerable efforts by the Environment Agency and its predecessors (the National Rivers Authority and Yorkshire Water), to improve the fish populations through stocking and some habitat improvement measures, the general status of the fisheries remains poor particularly in the Rivers Dearne and Rother. A strategic Aquatic Resources Management Plan (ARMP) targeting the bottlenecks to recovery and improvement in the water quality and fisheries habitat is proposed for the long-term sustainable improvement of the fisheries. Project Concept Notes and Logical Project Frameworks have been developed to address the water quality, habitat and fisheries rehabilitation problem. These constitute draft proposals for which additional information would be needed before projects can be progressed.
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Cohen, Jason Blake. "Urban-scale impacts on the global-scale composition and climate effects of anthropogenic aerosols." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62485.
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Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 247-256).
A reduced form meta model has been produced to simulate the effects of physical, chemical, and meteorological processing of highly reactive trace species in hypothetical urban areas, which is capable of efficiently simulating the urban concentration, surface deposition, and net mass flux of these species. A polynomial chaos expansion and the probabilistic collocation method have been used for the metamodel, and its coefficients were fit so as to be applicable under a broad range of present-day and future conditions. The inputs upon which this metamodel have been formed are based on a combination of physical properties (average temperature, diurnal temperature range, date, and latitude), anthropogenic properties (patterns and amounts of emissions), and the surrounding environment (background concentrations of certain species). Probability Distribution Functions (PDFs) of the inputs were used to run a detailed parent chemical and physical model, the Comprehensive Air Quality Model with Extensions (CAMx), thousands of times. Outputs from these runs were used in turn to both determine the coefficients of and test the precision of the metamodel, as compared with the detailed parent model. The deviations between the metamodel and the parent mode for many important species (03, CO, NO2, and BC) were found to have a weighted RMS error less than 10% in all cases, with many of the specific cases having a weighted RMS error less than 1%. Some of the other important species (VOCs, PAN, OC, and sulfate aerosol) usually have their weighted RMS error less than 10% as well, except for a small number of cases. These cases, in which the highly non-linear nature of the processing is too large for the third order metamodel to give an accurate fit, are explained in terms of the complexity and non-linearity of the physical, chemical, and meteorological processing. In addition, for those species in which good fits have not been obtained, the program has been designed in such a way that values which are not physically realistic are flagged. Sensitivity tests have been performed, to observe the response of the 16 metamodels (4 different meteorologies and 4 different urban types) to a broad set of potential inputs. These results were compared with observations of 03, CO, formaldehyde, BC, and PM10 from a few well observed urban areas, and in most of the cases, the output distributions were found to be within ranges of the observations. Overall, a set of efficient and robust metamodels have been generated which are capable of simulating the effects of various physical, chemical, and meteorological processing, and capable of determining the urban concentrations, mole fractions, and fluxes of species, important to human health and the climate. The point of developing these computationally efficient metamodels of urban processing is so that they can be used in the context of global modeling efforts. In specific, urban-scale processing has long been excluded in global 3D chemical transport models due to its large computational demands. In this thesis, the metamodel is used to simulate this processing, and compare a set of results against the more traditional approach of dilution of emissions into large grid boxes. This metamodel provides a tool to simulate, in a global 3D model, the effects of cities around the world on aerosol chemistry, physics, and radiative effects at the global scale. It is then demonstrated that a significant Bias Error = (Dilution Approach - Urban Processing) / Urban Processing is incurred due to the ignoring of urban processing. Specifically, the globally averaged monthly minimum, monthly maximum, and monthly average bias error caused by ignoring urban processing on the total aerosol surface concentration (+0.23, +0.28, and +0.26), the total aerosol column abundance (+0.43, +0.61, and +0.51), the AOD (+0.35, +0.50, and +0.42), and the AAOD (+0.01, +0.18, and +0.09), respectively. This leads to a significant Error = (Dilution Approach - Urban Processing) for the globally averaged monthly minimum, monthly maximum, and monthly average error for the top of the atmosphere radiative forcing (-0.414, -0.168, and -0.272 W/m 2), the surface radiative forcing (-1.02, -0.352, and -0.448 W/m 2), and the atmospheric radiative forcing (-0.004, +0.849, and +0.176 W/m 2 ), respectively. These results show that failure to consider urban scale processing leads to significantly more negative aerosol radiative forcing in the dilution case, as compared to when detailed urban scale processing is considered.
by Jason Blake Cohen.
Sc.D.
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Warwick-Evans, V. C. "Assessing the potential impacts of anthropogenic disturbance on seabirds : a case study from Alderney." Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/3001637/.
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Seabirds are threatened by multiple anthropogenic pressures in the marine environment. These pressures may be short- or long- term and impacts may be either direct or indirect and affect reproduction or survival. Marine Renewable Energy Installations (MREIs) provide a relevant, and spatially explicit, example of such pressures. However, there is currently very little empirical evidence as to how MREIs will impact seabirds. Studies have shown that potential impacts are likely to be species and device specific, temporary or long term, and both positive and negative. Current approaches to predict and assess these impacts from MREIs rely on understanding the species- specific risk of devices (e.g. by making predictions based on the ecology of the seabird), the occurrence of individual species at-sea (e.g. from boat-based surveys), and demographic studies of breeding populations (e.g. through long-term ringing studies). However, these approaches are limited in their ability to detect changes in the distribution of seabirds at-sea and at breeding colonies. They may omit the impacts on non-breeding birds, and overlook the cumulative impacts of multiple pressures on specific populations when predicting potential impacts. Alderney in the English Channel hosts internationally and nationally important seabird colonies, in addition to providing a suitable environment for the installation of tidal turbines. Additionally, the home range area of the colony of Northern gannets Morus bassanus breeding just offshore of Alderney overlaps with nine sites proposed for the development of MREIs, thus Alderney provides an ideal site for this type of study. This thesis explores simple approaches to predict and assess the impacts of proposed MREIs on seabirds, and demonstrates how the large amount of existing seabird tracking data can be used to predict the colony specific impacts of spatial change on seabirds. These approaches are developed at our Alderney study site but are broadly applicable elsewhere. Overall our results suggest that the MREIs proposed for development around Alderney and the English Channel are unlikely to cause population level impacts to the seabirds breeding on, and around, Alderney. With ever increasing human pressures on the marine environment it is vital that we identify robust approaches with which to predict and monitor the impacts of these pressures. This thesis provides simple, robust and cost-effective approaches to predict and assess the potential impacts of spatial change on seabirds, and could be easily adapted for other sites, and for alternative types of spatial change.
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Whomersley, Paul. "Uses of benthic ecology in the assessment of anthropogenic impacts in the marine environment." Thesis, Edinburgh Napier University, 2009. http://researchrepository.napier.ac.uk/Output/3741.
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The ability to detect and manage anthropogenic disturbances in the marine environment is more important than ever, given increasing pressure from a range of sources and the growing awareness of the sensitivity of some marine habitats. The main aims of this study were to ascertain if intensity and type of disturbance were important factors to consider during the assessment of these disturbances. Throughout, various techniques were used and assessed, e.g. primary, derived, multivariate and biological indices, as tools capable of indicating changes within benthic communities. A methodology of selecting appropriate indices linked to the perturbation of interest was also trialled. Finally, the behaviour of meiofauna and macrofauna towards in situ burial was investigated. The effects of disturbance were found to be type, as well as, site-dependent. In some cases, the intensity of disturbance was found to have non-linear effects. Site and disturbance-specific species and trophic group responses were also observed. The method used to select appropriate indices raised important questions. How can it be ensured that observed changes in indicator values are part of a cause-effect relationship? And, how do we identify / choose which of the potential impacts of the disturbance in question to use as a pressure indicator? Community-specific responses and sensitivities of meiofauna and macrofauna to the physical disturbance associated with in-situ burial highlight the importance of using both faunal types in the assessment of the effects of seabed disturbance in the marine environment. It is clear that no simple method exists for detecting disturbance which is applicable to all sites and situations. Hence, careful consideration, informed by ecological knowledge of sites and species, needs to be given to each case.
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Hein, Catherine L. "River Network Structure: A Template for Understanding Predator-Prey Dynamics and Potential Anthropogenic Impacts." DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/352.
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A landscape perspective is critically important for understanding community structure, particularly in systems dominated by migratory fauna. I aimed to understand how the structure of riverscapes in Puerto Rico mediates potential anthropogenic impacts, predator-prey interactions, and the migratory behavior of a diadromous species. I surveyed fishes and shrimps at sites throughout two watersheds, designed transplant experiments that investigated the role of natural barriers on predator-prey interactions, and developed models of shrimp migration specific to a particular river network. I did not detect an effect of anthropogenic changes to the landscape on fish and shrimp species distributions in two watersheds that drain the Luquillo Experimental Forest. These communities were primarily affected by the position of natural barriers: predatory fish distributions were limited by waterfalls and most shrimp species were found upstream from fish barriers. Thus, steep terrain mediated predator-prey interactions between fishes and shrimps, with one shrimp (Atya lanipes) likely avoiding predation by migrating above fish barriers. Lab and field experiments provided the first mechanistic evidence for landscape-level predator-avoidance behavior by A. lanipes. Both postlarval and adult shrimp avoided the scent of three predatory fish species in a y-maze fluvarium. In natural streams above fish barriers, adult A. lanipes did not respond to the addition of fish scent, but adult abundances did decline when fish were added to in-stream cages. To integrate our ideas about how shrimp behaviors scale up to observed adult A. lanipes distributions across the landscape, we developed a set of nested models specific to a particular river network. The best models parameterized branch choice at nodes within the river network to be heavily weighted toward particular mid-elevation tributaries above fish barriers. Our models indicated that distance traveled above and below fish barriers had little effect on adult distributions. Because the number of migrants decreases with distance upstream, the latter result was likely an artifact of the model. In montane river systems with migratory fauna, scientists would benefit by creatively designing new experiments and models that incorporate river network structure, as this is the template upon which all processes occur.
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Maochuan, Hu. "IMPACTS OF CLIMATE CHANGE AND ANTHROPOGENIC ACTIVITIES ON CATCHMENT WATER BALANCE AND HYDROLOGIC EXTREMES." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215515.
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Rhodes, Monika, and n/a. "The Ecology and Conservation of the White-Striped Freetail Bat (Tadarida australis) in Urban Environments." Griffith University. Australian School of Environmental Studies, 2006. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20070314.114451.
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Of all anthropogenic pressures, urbanisation is one of the most damaging, and is expanding in its influence throughout the world. In Australia, 90% of the human population live in urban centres along the eastern seaboard. Before European settlement in the early 1800s, much of the Australia's East coast was dominated by forests. Many of the forest dependent fauna have had to adapt to forest fragmentation and habitat loss resulting from clearing for urbanisation. However, relatively few studies have investigated the impact of urbanisation on biodiversity. This is especially true for the remaining fauna in large metropolitan areas, such as Melbourne, Sydney and Brisbane. The physical and conceptual context of this thesis is the increasing impact of urbanisation and the potentially threatening factors to forest dependent fauna. Bats were selected because they comprise a third of Australia's mammal species, and therefore form a major component of Australia's biodiversity. Very little is known about the ecology and conservation biology of hollow-dependent bats in general, but particularly in urban environments. The study was conducted in Brisbane, south-east Queensland, one of Australia's most biodiverse regions. More than a third of Australia's bat species occur in this region. A large insectivorous bat, the white-striped freetail bat (Tadarida australis), was selected to study two key resources in this urban area - hollow availability and foraging habitat. This thesis also examined if artificial roost habitat could provide temporary roosts for white-striped freetail bats and other insectivorous bats and assessed whether these bat boxes can be used as a conservation tool in urban environments where natural hollow-availability is limited. The white-striped freetail bat is an obligate hollow-dweller and roosted largely in hollows of old or dead eucalypts throughout Brisbane's urban matrix. These roost trees harboured significantly more additional hollow-dependent species compared to control trees of similar age, height, and tree diameter. Roost cavities inside trees often exceeded 30 cm in diameter. Furthermore, maternity colonies used cavities of hollow trunks, which often extended into major branches, to roost in big numbers. Therefore artificial alternatives, such as small bat boxes, may provide temporary shelter for small roosting groups, but are unlikely to be suitable substitutes for habitat loss. Although five bat species used bat boxes during this study, the white-striped freetail bat was not attracted into bat boxes. Roost-switching behaviour was then used to quantify associations between individual white-striped freetail bats of a roosting group. Despite differences in gender and reproductive seasons, the bats exhibited the same behaviour throughout three radio-telemetry periods and over 500 bat-days of radio-tracking: each roosted in separate roosts, switched roosts very infrequently, and associated with other tagged bats only at a communal roost. Furthermore, the communal roost exhibited a hub of socialising between members of the roosting group especially at night, with vocalisation and swarming behaviour not found at any of the other roosts. Despite being spread over a large geographic area (up to 200 km2), each roost was connected to others by less than three links. One roost (the communal roost) defined the architecture of the network because it had the most links. That the network showed scale-free properties has profound implications for the management of the habitat trees of this roosting group. Scale-free networks provide high tolerance against stochastic events such as random roost removals, but are susceptible to the selective removal of hub nodes, such as the communal roost. The white-striped freetail bat flew at high speed and covered large distances in search for food. It foraged over all land-cover types found in Brisbane. However, its observed foraging behaviour was non-random with respect to both spatial location and the nature of the ground-level habitat. The main feeding areas were within three kilometers of the communal roost, predominantly over the Brisbane River flood plains. As the only mammal capable of flight, bats can forage above fragmented habitats. However, as this study showed, hollow-dependent insectivorous bats, including free-tailed bats, are specialised in their roosting requirements. The ongoing protection of hollow-bearing trees, and the ongoing recruitment of future hollow-bearing trees, is essential for the long-term conservation of these animals in highly fragmented landscapes. Furthermore, loss of foraging habitat is still poorly understood, and should be considered in the ongoing conservation of bats in urban environments.
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Mestre, Débora Jesuíno. "Planeamento de restauro de corredores fluviais na bacia do Rio Grande." Master's thesis, ISA, 2013. http://hdl.handle.net/10400.5/6470.
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Mestrado em Engenharia do Ambiente - Instituto Superior de AgronomiaAccording to the Water Framework Directive (WFD), which requires Member States to take measures in order to protect, enhance and restore the superficial water bodies, looking to attain a good water quality status, the work at hand aims at assessing the ecological status of the Rio Grande water bodies, by implementing the Predicted Ecological State methodology. This methodology allows the division of the fluvial ecosystem in sections with homogenous features, the identification of its degradation level through the measurement of local anthropogenic pressures and plan rehabilitation measures and actions so as to achieve the goal set by the WFD.
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Lalley, Jennifer S. "Lichen-dominated soil crusts in the hyper-arid Namib Desert : anthropogenic impacts and conservation implications." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417605.
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Geedicke, Ina [Verfasser], and Kai [Akademischer Betreuer] Jensen. "Anthropogenic impacts on mangrove and saltmarsh communities in eastern Australia / Ina Geedicke ; Betreuer: Kai Jensen." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2019. http://d-nb.info/1192913108/34.
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Strassmann, Kuno M. "Modeling anthropogenic impacts on the carbon cycle and climate : from land use to mitigation scenarios /." [S.l.] : [s.n.], 2008. http://www.zb.unibe.ch/download/eldiss/08strassmann_k.pdf.
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Menberu, M. W. (Meseret Walle). "Hydrology of peat-dominated headwater catchments:theories and empirical analysis of the impacts of anthropogenic disturbance." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526219370.
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Abstract Peatland drainage affects about half the peatland area in Finland. Drainage changes natural peatland hydrology and affects water quality through effects on peat decomposition, mineralization, and enhanced mobilization. Runoff water from degraded peatlands transports metals and nutrients and impairs downstream water quality. Peatland restoration through drain blocking can reverse or minimize the negative effects and return degraded peatlands to their natural state over time. In this thesis, a before-after-control-impact study was applied at national scale to 44 boreal peatlands representative of a south-north boreal climate gradient, to study peatland watertable and pore water quality responses to drainage and restoration. Runoff dynamics, watertable levels, and associated characteristics were studied after peatland forestry drainage and subsequent restoration at seven sites. Analysis of watertable-related hydrological responses of 24 drained and restored sites and 19 undisturbed control sites revealed that restoration generally returned watertable levels and fluctuations at restored sites to near-undisturbed levels. This created favorable high-watertable conditions under which peatland species typically flourish. Examination of drainage/restoration effects on local geochemical conditions by studying pore water quality at the same sites revealed that, compared with undisturbed sites, forestry drainage increased dissolved organic carbon (DOC), total phosphorus (Ptot), and total nitrogen (Ntot). Nutrient concentrations continued to increase in the first year after restoration because of significant peatland disturbance, but DOC and nutrient concentrations declined to near-undisturbed levels over time. Watertable level, soil and air temperature, peatland class, and trophic level influenced pore water quality. An investigation of catchment-scale runoff processes in response to drainage and restoration revealed the complexity of runoff dynamics in peatlands. The amount of event runoff water varied between sites, but disturbed sites had higher mean runoff efficiency than undisturbed sites. Raising the watertable increased mean runoff efficiency compared with drained and undisturbed control sites, as shown by higher mean event runoff coefficient. In periods of no rainfall, low flow in all treatment conditions (disturbed, restored, undisturbed) was similar. During rainfall, the drainage networks at disturbed sites created short flow paths and water reached the outlets faster. Watertable-related storage (i.e., specific yield) at disturbed sites was significantly smaller than at other sites, but restoration raised the watertable to near-undisturbed levels into the layer of less decomposed and significantly higher specific yield. Comparing the success of restoration against peatland ecological functions revealed some improvements to restoration techniques that could improve restoration efficiency. However, better hydrological indicators of peatland disturbance are neededTiivistelmä Suomessa on ojitettu iso pinta-ala turvemaita. Ojituksen seurauksena turvemaiden hydrologia on muuttunut ja valumavesien laatu heikentynyt orgaanisen aineksen hajoamisen, mineralisaation ja ravinteiden liikkeellelähdön seurauksena. Valumavedet sisältävät usein metalleja ja ravinteita, jotka heikentävät alapuolisten vesistöjen laatua ja ekologista tilaa. Turvemaiden ennallistaminen ojia tukkimalla tai patoamalla voi vähentää näitä haitallisia vaikutuksia ja palauttaa suoekosysteemin luonnollisen toiminnan ajan saatossa. Tässä väitöstyössä hyödynnettiin kansallista soiden ennallistamisen monitorointiverkostoa, jossa on vedenlaadusta, valunnasta ja vesipintojen korkeudesta aineistoa ennen ja jälkeen soiden ennallistamisen sekä vastaavaa aineistoa luonnontilaisilta vertailualueilta. Tämä aineisto mahdollisti ojituksen ja ennallistamisen hydrologisten vaikutusten tutkimisen ”Ennen-Jälkeen-Kontrolli” – asetelmalla. Tutkimuksessa oli 44 tutkimuskohdetta, jotka edustivat kattavasti Suomen eri ilmastovyöhykkeitä. Näistä seitsemällä kohteella tutkittiin myös valunnan muodostumisen dynamiikkaa turvemetsätalousmailla, ennallistetuilla soilla sekä luonnontilaisilla soilla. Tutkimuksen havaittiin, että ennallistamisen seurauksena vesipintojen taso ja vaihtelu palautui (24 kohdetta) lähelle luonnon tilaa (19 kohdetta). Tulos osoittaa, että kunnostus mahdollistaa suoekosysteemille tyypillisten kasvien palautumisen. Vedenlaatuun liittyvät selvitykset sen sijaan osoittivat, että ojituilla alueilla liuennut orgaaninen hiili (DOC), kokonaisfosfori (Ptot) ja kokonaistyppi (Ntot) pitoisuudet olivat korkeita huokosvesissä. Ravinnepitoisuudet kohosivat edelleen ensimmäisenä vuotena ennallistamisen jälkeen, sillä varsinaiset ennallistamistoimet (puiden kaato, ojien tukkiminen) aiheuttivat häiriötä alueella. Tästä huolimatta DOC ja ravinnepitoisuudet laskivat lähemmäksi luonnontilaisia vertailualueita seuraavina vuosina. Aineiston perusteella, vesikorkeus, maaperän ja ilman lämpötila, suotyyppi ja suon ravinnetaso vaikuttivat veden laatuun. Valunnan vasteet valuma-alueella osoittivat monimutkaisia valunta-sadantaprosesseja turvemailla. Nuoren veden osuus valunnasta sateiden jälkeen vaihteli suuresti tutkimuskohteilla, mutta ojitetuilla/myöhemmin ennallistetuilla kohteilla oli keskimääräistä suurempi valunnan osuus kuin luonnontilaisilla vertailualueilla. Vesikorkeuden nosto ennallistuksessa lisäsi valunnan määrää verrattuna ojitettuun tilanteeseen tai luonnontilaiseen tilanteeseen. Ajanjaksoilla, ilman sadantaa, valuntaprosessit olivat hyvin samankaltaiset ojitetuilla ja myöhemmin ennallistetuilla sekä luonnontilaisilla vertailualueilla. Sateiden jälkeen ojaverkosto muodosti lyhyitä virtausreittejä ja viipymää valuma-alueella. Vesivarastoa kuvaava ominaisantoisuus oli ojitetuilla aluilla merkittävästi heikompi kuin luonnontilaisilla kohteilla. Ennallistaminen vedenkorkeutta nostamalla sen sijaan näkyi merkittävästi korkeampana ominaisantoisuutena. Tätä selittää heikommin maatunut turvekerros suon pinnalla. Työn tulokset edistävät tietoa suokunnostuksen hydrologiasta. Tuloksia voidaan käyttää arvioimaan ja suunnittelemaan soiden ennallistamisen toimenpiteitä ja vaikutuksia
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Fernández-Martínez, Marcos. "On the role of nutrients, climate and anthropogenic impacts in spatio-temporal variability of forest productivity." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/385914.
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Els boscos són dels ecosistemes terrestres més importants en termes de fotosíntesi i segrest de carboni, perquè n’acumulen i en segresten en grans quantitats, com a biomassa i com a matèria orgànica del sòl. A més, els boscos proporcionen polsos de recursos, a traves de la producció de fruits, que poden comportar efectes en cascada a través de la xarxa tròfica de l’ecosistema.
L’objectiu d’aquesta tesi és caracteritzar l’estructura i el funcionament dels boscos i quantificar llurs productivitats ecosistèmiques. La nostra recerca s’ha centrat en entendre els controls del balanç de carboni i de la producció de fruits en ecosistemes forestals. En aquesta tesi, hem intentat discernir entre els efectes de la disponibilitat de nutrients, del clima, de la variabilitat meteorològica interanual i dels impactes antropogènics en la variabilitat espai-temporal de la productivitat forestal.
Els resultats indiquen que l’edat del bosc, la disponibilitat d’aigua i la llargada de l’època càlida són els controls més importants dels estocs i fluxos de carboni i les eficiències en l’ús dels recursos. Malgrat això, el balanç del carboni dels boscos ve fortament determinat per la disponibilitat de nutrients del sòl. Els boscos fèrtils segresten el 33 ± 4% del carboni fotosintetitzat, mentre que els boscos infèrtils en segresten només el 6 ± 4%. A més, un cop tingut en compte l’efecte de l’edat, la relació biomassa-producció primària neta de les branques, tiges i arrels gruixudes estava positivament relacionada amb la disponibilitat de nutrients, contràriament al que passava amb les arrels fines. D’altra banda, vam trobar que l’augment de concentració del CO2 atmosfèric ha contribuït a augmentar la producció primària bruta i el segrest de carboni en un 1% anual des de l’any 1995 fins al 2011. Els resultats indiquen que, a Europa i els Estats Units, la reducció en la deposició de sofre ha comportat un augment més gran en la respiració que no pas en la fotosíntesi de l’ecosistema.
Els resultats mostren que la producció de fruits en boscos centre-Europeus oscil·la entre els 10 i els 40 g C m-2 any-1 i fa servir entre el 0.5 i el 3% del carboni fotosintetitzat. Els boscos amb elevades concentracions foliars de zinc i fòsfor produeixen més fruits i presenten una irregularitat interanual menor. A més, vam trobar que la producció interanual de fruits estava controlada per la variabilitat de la Oscil·lació de l’Atlàntic Nord, amb una importància major que les condicions atmosfèriques locals predint la producció de fruits. En boscos de Quercus ilex i Quercus pubescens vam trobar que l’estrès hídric de la primavera era el factor més rellevant explicant la variabilitat interanual en la producció d’aglans, mentre que la variabilitat en la producció de pol·len no presentava cap efecte. També vam demostrar que la producció de fruits pot ser predita fent sevir índexs de vegetació mitjançant la teledetecció per satèl·lit com l’”enhanced vegetation index” (EVI). Les grans produccions d’aglans en Quercus ilex van ser determinades per unes bones condicions de la vegetació durant els mesos previs a la collita i per unes bones condiciones hídriques primaverals. Finalment, vam demostrar la utilitat de l’índex de disparitat consecutiva (D) i les seves avantatges respecte el coeficient de variació (CV) en avaluar la variabilitat temporal. Vam trobar que D era menys depenent que la mitjana que el CV, a banda de tenir en compte l’autocorrelació de les sèries temporals.
Els resultats d’aquesta tesi obren la porta a un bon nombre de noves hipòtesis que mereixen ser testades en un futur proper. A més, aquesta tesi suposa un bon exemple del que les grans bases de dades poden oferir al camp de l’ecologia.Forests are among the most important terrestrial ecosystems in terms of photosynthesis and carbon sequestration because they accumulate and sequester large amounts of carbon, both as living tissues and as soil organic matter. Forests also provide large resource pulses through fruit crops that may present cascading effects through the food web of the ecosystem. The objective of the thesis was to characterize the structure and functioning of forests and to quantify ecosystemic productivity. We focused our research on understanding the main controls of carbon balance and fruit production in forest ecosystems. In this thesis, we try to disentangle the effects of nutrient availability, stand characteristics, climate and weather variability and anthropogenic impacts on spatio-temporal variability in forest productivity. We found that stand age, water availability, and length of the warm period were the main factors controlling forest carbon stocks, fluxes and resource-use efficiencies. Standing biomass and carbon fluxes were strongly correlated to each other at the global scale and both were controlled by climate (mainly water availability and temperature) and stand characteristics such as the age of the stand or leaf type. However, carbon balance of the ecosystem strongly depended on the nutrient availability. We found that, nutrient-rich forests sequester 33 ± 4% of photosynthesized carbon while nutrient-poor forests only sequester 6 ± 4% of it. At the ecosystem level, this effect of nutrient availability was independent of climate, stand age or the management of the stand. In addition, once the effect of stand age was removed the biomass-to-net primary production ratio of woody tissues (branches, stems, and coarse roots) was positively influenced by nutrient availability, but it had a negative effect on the fine root fraction. Regarding temporal variability of carbon fluxes, we found that increasing CO2 has increased gross primary production and carbon sequestration, on average, by 1% annually from 1995 to 2011. We also found that the reduction of sulphur deposition in Europe and the USA involves a higher recovery in ecosystem respiration than in gross primary production. Regarding fruit production, we found that fruit production ranges from 10 to 40 g C m-2 y-1 and uses around 0.5 - 3% of the photosynthesized carbon in European forests. We found that forests with higher foliar zinc and phosphorus concentrations, produced larger fruit crops and presented less irregularity in interannual fruit crop size. Additionally, we found interannual fruit variability to be controlled by the interannual variability of the North Atlantic Oscillation, having a more prominent importance than local weather variables in predicting it. In Quercus ilex and Quercus pubescens stands we found that spring water deficit was the most relevant factor in explaining interannual variability in acorn production and that interannual differences in pollen production did not influence acorn crop size. We demonstrated that fruit production can be predicted using remotely sensed vegetation indices, such as the enhanced vegetation index (EVI). Our results suggested that fruit crop size in Quercus ilex was driven by a combination of two factors, i.e. good vegetation conditions during several months prior to fruit harvest, and wet weather during spring. Finally, we demonstrated the usefulness of the consecutive disparity index (D) and its advantages with respect to the coefficient of variation (CV). We found D to be less dependent on the mean than the CV while also taking into account the autocorrelation of the time series. The results of this thesis open the door to a wide range of new ideas and hypotheses worth to test in the near future. This thesis is also a good example of what the so called “big data” can offer to ecologists and environmental scientists.
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Odume, Oghenekaro Nelson. "Application of macroinvertebrate based biomonitoring approaches to assess anthropogenic impacts in the Swartkops River, South Africa." Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1006199.
Full textAbstract:
A growing human population accompanied by urbanisation and industrialisation have led to over exploitation and pollution of freshwater resources and have consequently impacted on aquatic ecosystem health. The Swartkops River in the Eastern Cape of South Africa is no exception. It drains a heavily industrialised catchment which has led to deterioration of its water quality due to pollution. Integrated water resources management (IWRM) requires the concurrent sustainable use of water resources and the protection of aquatic ecosystem health. Macroinvertebrates are well known for their ability to reflect the health of the environment in which they live, thus they were used to assess anthropogenic impacts in the Swartkops River for this study. Macroinvertebrate based biomonitoring approaches, including the South African Scoring System version 5 (SASS5); a multimetric approach involving 19 metrics; Chironomidae community assessments and screening of morphological deformities in Chironomidae larvae, were applied at four selected sampling sites to assess environmental water quality in the Swartkops River. Macroinvertebrates were sampled us ing the SASS5 protocols. Chironomidae were mounted and identified as far as practically possible using available keys. Mentum, ligula, mandible, paraligula and antenna in Chironomidae larvae were screened for deformities. Physical and chemical water quality variables were measured at each of the selected sampling sites. All data were subjected to relevant statistical analyses. Of the four sites sampled during the study period, results revealed that water quality at site 1 was the least impacted with highest SASS5 scores, average score per taxa (ASPT) values, richness, diversity, equitability and Ephemeroptera –Plecoptera-Trichoptera (EPT) richness, as well as least incidences of chironomid deformities. Water quality at site 2 was considered the next least impacted with higher SASS5 scores, A SPT values, richness, diversity and equitability, and lower incidences of deformities compared to sites 3 and 4. SASS5 scores and ASPT values revealed that both sites 3 and 4 were critically modified but the multimetric analysis, Chironomidae community assessment and incidences of deformities in Chironomidae larvae indicated that site 3 is the most impacted of the four sampling sites, with least species diversity, richness, equitability and highest incidences of deformities. The study revealed the importance of multicriteria approach to environmental biomonitoring as an integrated water resources management tool, and based on the results, site 3, as the most impacted, could be prioritised for restoration intervention.
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Bhadra, Sourav. "Assessing the Impacts of Anthropogenic Drainage Structures on Hydrologic Connectivity Using High-Resolution Digital Elevation Models." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/theses/2573.
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Stream flowline delineation from high-resolution digital elevation models (HRDEMs) can be problematic due to the fine representation of terrain features as well as anthropogenic drainage structures (e.g., bridges, culverts) within the grid surface. The anthropogenic drainage structures (ADS) may create digital dams while delineating stream flowlines from HRDEMs. The study assessed the effects of ADS locations, spatial resolution (ranged from 1m to 10m), depression processing methods, and flow direction algorithms (D8, D-Infinity, and MFD-md) on hydrologic connectivity through digital dams using HRDEMs in Nebraska. The assessment was conducted based on the offset distances between modeled stream flowlines and original ADS locations using kernel density estimation (KDE) and calculated frequency of ADS samples within offset distances. Three major depression processing techniques (i.e., depression filling, stream breaching, and stream burning) were considered for this study. Finally, an automated method, constrained burning was proposed for HRDEMs which utilizes ancillary datasets to create underneath stream crossings at possible ADS locations and perform DEM reconditioning. The results suggest that coarser resolution DEMs with depression filling and breaching can produce better hydrologic connectivity through ADS compared with finer resolution DEMs with different flow direction algorithms. It was also found that stream burning with known stream crossings at ADS locations outperformed depression filling and breaching techniques for HRDEMs in terms of hydrologic connectivity. The flow direction algorithms combining with depression filling and breaching techniques do not have significant effects on the hydrologic connectivity of modeled stream flowlines. However, for stream burning methods, D8 was found as the best performing flow direction algorithm in HRDEMs with statistical significance. The stream flowlines delineated using the proposed constrained burning method from the HRDEM was found better than depression filling and breaching techniques. This method has an overall accuracy of 78.82% in detecting possible ADS locations within the study area.
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Pucko, Carolyn Ann. "The Impacts of Multiple Anthropogenic Disturbances on the Montane Forests of the Green Mountains, Vermont, USA." ScholarWorks @ UVM, 2014. http://scholarworks.uvm.edu/graddis/315.
Full textAbstract:
How and why species’ ranges shift has long been a focus of ecology but is now becoming increasingly important given the current rate of climatic and environmental change. In response to global warming, species will need to migrate northward or upward to stay within their climatic tolerances. The ability of species to migrate will determine their fate and affect the community compositions of the future. However, to more accurately predict the future extent of species, we must identify and understand their responses to past and current climatic and environmental changes. The first place change is expected to occur is within ecotones where the ranges of many species converge and individuals exist at the limits of their environmental tolerances. In montane regions, these boundaries are compressed, creating a situation in which even relatively small changes in conditions can lead to shifts in the elevational ranges of species.
In this dissertation, I examine the responses of forests in the Green Mountains of Vermont to recent climatic and environmental change in an attempt to understand how future climate change will affect their location and composition. I focus on the Boreal-Deciduous Ecotone (BDE), where the high elevation spruce-fir forests converge with the lower elevation northern hardwoods. In addition to investigating adult trees within the BDE, I also examine the responses of understory herbs and tree seedlings to changes in environmental and climatic factors. Factors considered in these investigations include temperature, soil environment, light environment, invasive species, competition, disturbance and many others. I will examine the complex range of responses in forest species that results from prolonged exposure to these forces alone and in combination.
I have attempted to identify the responses of forest species to environmental changes by resurveying historic vegetation plots (Chapter 2), experimentally manipulating the growing environment of tree seedlings (Chapter 3) and performing dendrochronological analyses on tree rings (Chapter 4). Through my resurvey of historic vegetation plots, I determined the degree to which understory species have shifted as individuals or as groups. I also identified a set of novel understory communities that have developed since the 1960's in response to recent climate change, acid deposition and invasive species (Chapter 2). By transplanting and artificially warming tree seedlings, I identified factors responsible for limiting the growth and survival of northern hardwood species above the BDE. Temperature was the primary factor limiting sugar maple (Acer saccharum) at high elevations, while yellow birch (Betula alleghaniensis) was limited almost exclusively by light (Chapter 3). Dendrochronological studies of sugar maples indicated that prolonged exposure to acidified soils has only recently caused growth declines and has altered their relationship to climate (Chapter 4). Together, these studies have produced a cohesive picture of how northeastern montane forests have responded to recent climate change and other anthropogenic impacts. These findings can be used to help predict future species' ranges and identify species that may not be capable of migrating fast enough on their own to keep pace with changes in climatic conditions.
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Wagstaffe, Jessica. "Anthropogenic impacts on an oligotrophic clear water lake in Halland, Sweden, assessed from two different data sets." Thesis, Högskolan i Halmstad, Bio- och miljösystemforskning (BLESS), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-23287.
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Lake Skärsjön is a dimictic, oligotrophic, clear water lake with bottom plant communities including the rare Nostoc zetterstedtii. The lake is located in western Sweden, south of Gothenburg. During the late 1970s to mid-1980s, there was fish cage farming located near the outlet of the lake. When the fish farming was first introduced, there was concern over the health of the late which prompted a monitoring study which was conducted from 1980 to 1990 by the County Administration Board (regional governing body of Sweden). Starting in 1983, another National Monitoring study commenced simultaneously with the 10 year study. This monitoring study had one site taking measurements from 0.2-2m and collected the same data as the 10 year study. There were notable changes starting in 1985, the year the fish farming was closed down. After these changes, there are patterns indicating the lake returning to similar conditions before 1985. The pH of the lake is increasing and the acidity decreasing which reflects the ongoing decrease in atmospheric sulphur deposition and concentration in the lake. Overall, the impacts from the fish farming may have been more intense if it was located farther from the lake outlet. This would have allowed nutrient emissions from the fish cages to influence the lake more severely before exiting through the outlet. The lake is slowly recovering from this anthropogenic event and the current monitoring program, the National Monitoring study, should remain intact.
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Huff, David Allan. "Water Quality of the Upper Little Miami River Watershed in Ohio: Impacts of Natural and Anthropogenic Processes." Wright State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=wright1430112740.
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Pereira, Costa Raquel Filomena. "Behavioural flexibility in wild mountain gorillas and implications for its conservation: Anthropogenic impacts on species-specific behaviours." Kyoto University, 2021. http://hdl.handle.net/2433/261605.
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付記する学位プログラム名: 霊長類学・ワイルドライフサイエンス・リーディング大学院Kyoto University (京都大学)
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新制・課程博士
博士(理学)
甲第22878号
理博第4644号
新制||理||1668(附属図書館)
京都大学大学院理学研究科生物科学専攻
(主査)准教授 足立 幾磨, 准教授 Michael Alan Huffman, 教授 高田 昌彦
学位規則第4条第1項該当
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Duke, Charles Trevor. "Identifying Humanized Ecosystems: Anthropogenic Impacts, Intentionality, and Resource Acquisition at Crystal River (8CI1) and Roberts Island (8CI41)." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5941.
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The impact of human activity on ecosystems is an issue at the forefront of global concern. Marine ecosystems are a particular concern, given their importance for human sustenance. Through the removal of species that are highly susceptible to the effects of overfishing, global fisheries have been driven to near collapse in recent decades. The long-term effects of such practices has resulted in declines in mean trophic level of aggregate fish catches over time, as well as decreasing diversity of species available for regular harvest (Jackson et al. 2001; Pauly et al. 1998). These supposedly “modern” problems have been recently identified in archaeological contexts, and attest to the extent of anthropogenic ecosystem alteration that has occurred since humans first began intensively exploiting marine ecosystems (Erlandson and Rick 2010; Quitmyer and Reitz 2006; Reitz 2004; Wing and Wing 2001). Here, I evaluate the degree of change in mean trophic level, diversity, and equitability of midden deposits at Crystal River and Roberts Island, two roughly contemporaneous Middle-to-Late Woodland Period (AD 1to 1000) mound complexes located on the west-central Florida Gulf Coast. This research identifies the extent to which humans altered the characteristics of the estuarine ecosystem surrounding the two sites, promotes alternative theoretical perspectives on past human-environment interactions, and provides modern ecosystems management agencies with a temporally-expansive data set to aid in future ecosystem conservation efforts.