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Dissertations / Theses on the topic 'Predador de topo'

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Published: 4 June 2021

Last updated: 4 February 2022

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1

Crisóstomo, Luísa João Pereira. "Análise biogeográfica da dieta de um predador de topo ao longo da região Paleártica." Master's thesis, Universidade de Évora, 2016. http://hdl.handle.net/10174/18927.

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Existem vários estudos sobre a dieta de predadores de topo a uma escala local, mas o estudo da dieta de uma espécie ao longo de diferentes regiões geográficas poderá permitir a deteção de certos padrões e variações ecológicas. Para estudar a variação biogeográfica da dieta do bufo-real (Bubo bubo) ao longo do Paleártico criou-se uma base de dados baseada em 192 estudos. Pretendia-se analisar padrões em macro-escala de descritores da dieta e avaliar o efeito de diferentes condições ambientais, de descritores da paisagem e da disponibilidade de presas. Registaram-se 346813 presas de 698 espécies

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2

Palmeira, Francesca Belem Lopes. "Co-ocorrência, interações tróficas e distribuição potencial da onça-pintada (Panthera onca) no bioma Amazônia." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-17092015-111206/.

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Predadores de topo desempenham um papel importante na manutenção dos sistemas em que eles ocorrem porque influenciam diretamente a estrutura e a dinâmica de comunidades. Desta forma, este estudo descreveu alguns mecanismos de co-ocorrência espaço-temporal entre a onça-pintada (Panthera onca) e duas espécies de mesopredadores (Puma concolor e Leopardus pardalis), o seu controle top-down na comunidade de mamíferos e os requerimentos ambientais que determinam a sua distribuição no bioma Amazônia. Para as análises de co-ocorrência espaço-temporal foram utilizados o modelo de ocupação e a densidade

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3

FERREIRA, Guilherme Vitor Batista. "Ecologia alimentar e distribuição espaço-temporal das diferentes fases ontogenéticas da espécie Cynoscion acoupa no estuário do Rio Goiana (PE/PB)." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/17133.

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Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-06-20T18:42:06Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação (G. Ferreira).pdf: 2368229 bytes, checksum: e7d27dd236d3848f67692455d0a94426 (MD5)<br>Made available in DSpace on 2016-06-20T18:42:06Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação (G. Ferreira).pdf: 2368229 bytes, checksum: e7d27dd236d3848f67692455d0a94426 (MD5) Previous issue date: 2016-02-01<br>Capes<br>Este estudo avalia a influência

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4

Lourenço, Rui Nascimento Fazenda. "Predatory interactions among vertebrate top predators superpredation and intraguild predation by large raptors." Doctoral thesis, Universidade de Évora, 2011. http://hdl.handle.net/10174/14789.

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Nesta tese estudaram-se as interacções predatórias entre vertebrados predadores de topo (predação intraguilda e superpredação), utilizando quatro aves de rapina de grande porte como modelos de superpredadores: Bufo-real, Açor, Águia-real, e Águia de Bonelli. A superpredação em aves de rapina é um fenómeno abrangente, que pode variar entre espécies, e mais frequente em paisagens mais humanizadas. Os meso-predadores não são recursos energeticamente relevantes para as aves de rapina, e o seu consumo está associado à diversificação da dieta resultante da diminuição das presas habituais. A eliminaç

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5

Jones, Esther Lane. "Spatial ecology of marine top predators." Thesis, University of St Andrews, 2017. http://hdl.handle.net/10023/12278.

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Species distribution maps can provide important information to focus conservation efforts and enable spatial management of human activities. Two sympatric marine predators, grey seals (Halichoerus grypus) and harbour seals (Phoca vitulina), have overlapping ranges but contrasting population dynamics around the UK; whilst grey seals have generally increased, harbour seals have shown significant regional declines. A robust analytical methodology was developed to produce maps of grey and harbour seal usage estimates with corresponding uncertainty, and scales of spatial partitioning between the sp

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6

Cordes, Line Søltoft. "Demography and breeding phenology of a marine top predator." Thesis, University of Aberdeen, 2011. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=183669.

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Worldwide harbour seal populations are showing differing and fluctuating trends in abundance, but the drivers of change remain uncertain. Within the Moray Firth, NE Scotland, count surveys carried out over the last 20 years highlighted the development of a new breeding site, providing a unique opportunity to carry out an individual-based study of harbour seal demography and pupping phenology using photo-identification techniques within a mark-recapture framework. Sightings of individual seals suggested that a large proportion of harbour seals are year-round residents at haul-out sites. Both se

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7

Ware, Remy Lian. "The invasive ladybird Harmonia axyridis as a top intraguild predator." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612130.

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8

Woodward, Guy. "Invasion of a stream food web by a new top predator." Thesis, Queen Mary, University of London, 1999. http://qmro.qmul.ac.uk/xmlui/handle/123456789/1636.

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A large predator, the nymph of the dragonfly Cordulegaster boltonii (Anisoptera) (Donovan), has recently invaded Broadstone Stream, an acid headwater in southern England. Because of its large size, the invader established itself as a new top predator. The Broadstone Stream food web is exceptionally detailed and the community has been studied since the early 1970s. The invasion of C boltonii, therefore, provided a rare opportunity to investigate the effects of a potentially strong perturbation upon a well-described system. At the peak of the invasion C boltonii density exceeded seventy nymphs p

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9

Pasanen, Mortensen Marianne. "Anthropogenic impact on predator guilds and ecosystem processes : Apex predator extinctions, land use and climate change." Doctoral thesis, Stockholms universitet, Zoologiska institutionen, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-100720.

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Humans affect ecosystems by changing species compositions, landscape and climate. This thesis aims to increase our understanding of anthropogenic effects on mesopredator abundance due to changes in apex predator status, landscape and climate. I show that in Eurasia the abundance of a mesopredator, the red fox (Vulpes vulpes), is limited top-down by the Eurasian lynx (Lynx lynx) and bottom-up by winter severity. However, where lynx has been eradicated, fox abundance is instead related to bottom-factors such as cropland (paper I, II). Fox abundance was highest when croplands constituted 25% of t

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10

Woodgate, Zoe Anne. "Determinants of predator abundance in northern KwaZulu-Natal: top-down or bottom-up?" Bachelor's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/13032.

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Includes bibliographical references.<br>As protected areas ultimately aim to successfully conserve natural predator populations, an understanding of the non-anthropogenic drivers of their population change is critical. Both bottom-up (e.g. food limitation, competition) and top-down (e.g. predation, interference) processes play an important role in structuring predator guilds, yet there is a poor understanding of their relative importance. Here, I investigated whether the relative abundance of mesopredators, facultative scavengers, and an apex predator were affected primarily by bottom-up proce

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11

Le, Roux Elizabeth. "The role of apex predators in ecosystem function: fear triggered cascades regulated by differential prey vulnerability." Thesis, Nelson Mandela Metropolitan University, 2016. http://hdl.handle.net/10948/14774.

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Trophic cascades involving large terrestrial mammals are very seldom empirically demonstrated. The high species diversity often associated with terrestrial systems is thought to modulate the strength of trophic cascades. In speciose systems, species often vary in vulnerability to consumption, hence some species are less responsive to top-down pressure. African large mammalian herbivores are highly diverse and vary greatly in body size, a characteristic linked to vulnerability to predation. Moreover, Africa is one of the last places to still support megaherbivores, species that have grown large

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12

Philpott, Evelyn. "Examining potential effects of marine renewable energy developments on top predators." Thesis, University of Aberdeen, 2013. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=210583.

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This thesis uses data collected over three summers in 2010, 2011 and 2012 at the Isle of May National Nature Reserve, Scotland to examine top predator presence and behaviour in a moderately fast tidal stream site. Fieldwork consisted of an intensive land based observation survey of seabirds at sea, acoustic monitoring of small cetaceans and the deployment of a suite of oceanographical tools to simultaneously collect data on a fine temporal scale over a study area of ~1.5km2. The aim of the study was to examine the potential effects of marine renewable energy developments on top predator behavi

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13

Mamede, Nuno Miguel Guerreiro. "Relações ecológicas entre ouriços-do-mar e os seus predadores e presas no sudoeste de Portugal Continental." Master's thesis, Universidade de Évora, 2014. http://hdl.handle.net/10174/11483.

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Os ouriços-do-mar desempenham um papel-chave na estrutura das comunidades bentónicas do litoral rochoso, podendo exercer uma intensa herbivoria sobre os produtores primários. Este estudo teve como objetivo analisar o papel ecológico do ouriço-do-mar Paracentrotus lividus na zona subtidal rochosa da costa sudoeste de Portugal continental, tanto como predador como presa, relacionando os três níveis tróficos: predadores de P. lividus, P. lividus e comunidade de macroalgas. Para tal, foram realizados vários estudos, cujos resultados indicam que na costa alentejana: (1) P. lividus aparenta ter um c

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14

Smurthwaite, Rebecca. "Diet and heavy metal uptake by two top predator species in the Tees estuary." Thesis, Durham University, 2006. http://etheses.dur.ac.uk/2651/.

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The key aim of the thesis was to estimate metal uptake and its seasonal variation from the diet by two predators from the Tees Estuary, harbour seals, Phoca vitulina and cormorants, Phalacrocorax carbo. The reproductive success of the colony of harbour seals, that has been re-establishing in the Tees Estuary since the late 1980ร, has been poor and metal loads maybe a potentially limiting factor. The diet of the predators was assessed and metal concentrations within the prey species were analysed. Median metal concentrations in Crustacea and fish species from the Tees Estuary were higher than r

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15

La, Ville Noemi di. "The Grey Wolf : habitat suitability analysis of a top predator species over its global range." Thesis, Cranfield University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245477.

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16

Bowling, Anna Marie. "The impact of a benthic omnivore on the biomagnification of mercury in top-predator fish." Oxford, Ohio : Miami University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1250890267.

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17

Lambert, Charlotte. "Top predators in marine ecosystem : their response to ocean spatio-temporal variability." Thesis, La Rochelle, 2016. http://www.theses.fr/2016LAROS010/document.

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Le milieu marin est un espace difficile à étudier et notre connaissance des cétacés et des oiseaux marins présente encore de nombreuses lacunes, notamment concernant leur distribution au large. Le milieu marin pélagique est caractérisé par une forte variabilité spatiotemporelle, les différents processus écologiques composant cet écosystème étant très dynamiques dans le temps et l'espace. Il est donc crucial pour ces espèces marines d'anticiper ces variations afin de se maintenir dans le milieu. Grâce à des campagnes en mer à grandes échelles réalisées en Manche, Golfe de Gascogne et Méditerran

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18

Amaral, Karina Bohrer do. "Influência do ambiente marinho no padrão de distribuição e na estrutura genética de mamíferos marinhos predadores de topo de cadeia." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/187250.

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Duas espécies de cetáceos apresentam padrões de distribuição peculiares ao longo da costa brasileira, muito provavelmente em resposta às condições hidrográficas e topográficas que ocorrem entre 20 e 33°S. A primeira espécie, a franciscana ou toninha (Pontoporia blainvillei), é um golfinho de distribuição restrita do Brasil até a Argentina, que ocorre primariamente na plataforma continental interna, raramente ultrapassando os 50 m de profundidade. Já a segunda espécie, o golfinho-pintado-do-Atlântico (Stenella frontalis), é um golfinho de distribuição restrita ao Oceano Atlântico, que ocupa pri

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Lorentzdotter, Helena. "Miljögiftsförekomster i utter (Lutra lutra) från Småland : Nuvarande status och förändringar över tid (1966-2014)." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-107650.

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The Swedish otter (Lutra lutra) population decreased markedly after the 1950’s and was considered to be seriously threatened for decades. Pollution from industries and other anthropogenic activities were suspected to be the major cause of the decline. The otter is a top-predator in aquatic systems and therefore particularly susceptible to bioaccumulative and toxic substances. For this reason, the species can be regarded as a valuable indicator of environmental health. Today, the Swedish otter population is increasing and has been reestablished in many areas. However, the otter is still missing

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Hanson, Nora N. "Examining the response of top marine predators to ecological change using stable isotope proxies." Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/3221.

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Monitoring the response of upper trophic level animals to ecological change is important to understanding the state and stability of ecosystems. Marine predators integrate information over large geographical scales and are relatively long-lived; furthermore, many of these organisms are restricted to terrestrial or freshwater habitats at certain times during their life history and are accessible to researchers. This thesis investigated the response of marine predators to ecological change at a variety of spatial and temporal scales using stable isotope ratio methods with the aims of developing

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21

Rodríguez, Lozano Pablo. "Fire legacies in Mediterranean streams: the key roles of the riparian canopy and the top predator on food webs." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/385275.

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Wildfires are expected to increase in frequency and intensity because of climate change and changes in land use and management. In last decades, the research on fire effects on aquatic systems has grown, but it has been mainly conducted in the short- and mid-term (<5 years). Therefore, longer time frames are needed to assess fire effects on freshwater ecosystems. For instance, fire impacts on riparian and upland forests can be long-lived and wildfires often extirpate fish populations from streams, which may not recover due to barriers within the river network. Regarding fish extirpations, it i

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Cormon, Xochitl. "Impacts of a top-predator emergence in an exploited ecosystem : North Sea hake and saithe. : Which interactions ? What consequences ?" Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10201/document.

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La population de lieu noir (Pollachius virens) de mer du Nord a une importance économique élevée pour les pêcheries européennes. Depuis une dizaine d’années, l’abondance du lieu noir a décliné, alors que le merlu (Merluccius merluccius), qui était peu pêché dans cette zone, a vu son abondance fortement augmenter. Ce travail se concentre sur la nature des interactions écologiques entre le lieu noir et le merlu en Mer du Nord afin de déterminer si la récente émergence du merlu dans cette zone pourrait expliquer, au moins en partie, le récent déclin du stock de lieu noir. Les résultats obtenus lo

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Shane, Keith Dennis. "Habitat-use and emigration patterns of two top predators stocked in a large flood-control impoundment." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1542722595138777.

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Reisinger, Ryan Rudolf. "Abundance and predatory impact of killer whales at Marion Island." Diss., University of Pretoria, 2011. http://hdl.handle.net/2263/27643.

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Killer whales are the oceans’ apex predator and are known to have important effects on ecosystems. At Subantarctic Marion Island, southern Indian Ocean, they have only been studied opportunistically, resulting in limited knowledge of their ecosystem impact here. This dissertation describes the prey and seasonal abundance, estimates the population size and assesses the predatory impact of killer whales on seals and penguins at Marion Island, using dedicated and opportunistic shore-based observations and photographic identification, from 2006 to 2009. During 823 sightings of killer whales at Mar

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Habegger, Maria Laura. "Bite force in two top predators, the great barracuda, Sphyraena barracuda and bull shark, Carcharhinus leucas, during ontogeny." [Tampa, Fla] : University of South Florida, 2009. http://digital.lib.usf.edu/?e14.2915.

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Brancart, Kendall. "Determining how risk effects predator-prey interactions of marine communities in the nearshore environment of South Bimini, The Bahamas." Thesis, NSUWorks, 2019. https://nsuworks.nova.edu/occ_stuetd/506.

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Predators often have strong top-down effects on ecosystems and are considered a priority for conservation and management. Predator activity can influence prey distribution, abundance, and foraging behaviors and are likely to influence habitat by impacting ecological and environmental characteristics as well as presence of competitor species. There are knowledge gaps of the functional diversity of fish assemblages, non-consumptive predator effects, and environmental effects on fish assemblages. With this study, effects of top marine predators, such as sharks and great barracuda, on diversity an

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Gazda, Stefanie K. "Examining sociological differences and the influence of prey distribution and environmental variability in the distribution of a top marine predator, the bottlenose dolphin (Tursiops truncatus)." Thesis, University of Massachusetts Boston, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10010739.

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<p> The purpose of this dissertation was to examine the influence of environmental variability on the distribution of prey, and the influence of prey spatial structure and habitat variability may have on the distributions of bottlenose dolphins (<i>Tursiops truncatus</i>). Additionally I examined how sociological differences (behavior type and the changes in a foraging behavior specific to Cedar Key Florida) influences the relative roles of bottlenose dolphins within the population. </p><p> The Gowans et al. scheme assumes that small groups form small communities and that foraging groups ar

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Hickerson, Cari-Ann Marie. "INTERACTIONS AMONG TOP-DOWN REGULATORS IN A TEMPERATE FOREST FLOOR ECOSYSTEM: EFFECTS ON MACROFAUNA, MESOFAUNA, MICROBES AND LITTER DECAY." Cleveland State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=csu1276104836.

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Cox, Samantha Lucy. "The role of physical oceanography on the distributions and foraging behaviours of marine mammals and seabirds in shelf-seas." Thesis, University of Plymouth, 2016. http://hdl.handle.net/10026.1/4579.

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Mid-latitude shelf-seas are highly productive regions that host a rich diversity of animals including large numbers of marine mammals and seabirds. These large vertebrate predators play a crucial role in the functioning of shelf-sea ecosystems. However, the combined effects of multiple anthropogenic stressors are driving unprecedented declines in many of their populations. Mitigating this depends upon effective conservation and integrated ecosystem based approaches to management, which require a comprehensive understanding of the habitat needs of marine predators. The foraging efficiencies of

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Wege, Mia. "Maternal foraging behaviour of Subantarctic fur seals from Marion Island." Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/37354.

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Foraging forms the cornerstone of an animal’s life-history. An individual's foraging success shapes the demography and health of a population. Understanding key facets of maternal foraging behaviour are crucial to get a holistic picture of both regional and local environmental factors that drive foraging behaviour. This study aimed to measure the maternal foraging behaviour of a marine top predator, the Subantarctic fur seal (Arctocephalus tropicalis), from Marion Island (MI) over a range of spatial and temporal scales. Arctocephalus tropicalis females from MI have one of the longest dur

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Habegger, María Laura. "Bite Force in Two Top Predators, the Great Barracuda, Sphyraena barracuda and Bull Shark Carcharhinus leucas, During Ontogeny." Scholar Commons, 2009. https://scholarcommons.usf.edu/etd/1996.

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Functional morphologists have extensively used measurements of performance to investigate the relationship among form, function and ecology through ontogeny. Among different measurements of performance bite force play a crucial role influencing fitness. Although, bite force has been thoroughly investigated among vertebrates, the majority of the studies on fishes have been concentrated only in small species. Consequently, this is the first study that compares the bite force performance in two large marine predators, the great barracuda (Sphyraena barracuda) and bull shark (Carcharhinus leucas).

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Giansiracusa, Sara. "Bioaccumulation of legacy and emerging contaminants in tuna species." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18305/.

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Environmental contamination of legacy contaminants has been of great concern worldwide because of their persistence and toxicity to humans and marine species. Only in the last decade, the presence and accumulation of emerging contaminants, and, consequently, their adverse effects in marine biota have been considered. The present research was performed to compare the different distribution of legacy contaminants (Pesticides, PCBs and PAHs) and emerging contaminants (UV filters and Fragrances) in the liver and muscle tissues of three tuna species living in different locations and with different

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Peschko, Verena [Verfasser], Stefan [Akademischer Betreuer] Garthe, and Karen [Gutachter] Wiltshire. "Ecology of top predators in the North Sea – Baseline for and effects of offshore wind power developments / Verena Peschko ; Gutachter: Karen Wiltshire ; Betreuer: Stefan Garthe." Kiel : Universitätsbibliothek Kiel, 2020. http://d-nb.info/1216503621/34.

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Bouchard, Krystle A. "FINDING THE TROPHIC TRICKLE: USING HERBACEOUS INDICATOR SPECIES TO INVESTIGATE PLANT RECOVERY FROM INTENSE BROWSING BY WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS) AFTER THE RE-COLONIZATION OF A TOP PREDATOR (CANIS LUPUS)." Wright State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=wright1253524947.

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Nowicki, Robert J. "Effects of Catastrophic Seagrass Loss and Predation Risk on the Ecological Structure and Resilience of a Model Seagrass Ecosystem." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2994.

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As climate change continues, climactic extremes are predicted to become more frequent and intense, in some cases resulting in dramatic changes to ecosystems. The effects of climate change on ecosystems will be mediated, in part, by biotic interactions in those ecosystems. However, there is still considerable uncertainty about where and how such biotic interactions will be important in the context of ecosystem disturbance and climactic extremes. Here, I review the role of consumers in seagrass ecosystems and investigate the ecological impacts of an extreme climactic event (marine heat wave) and

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Zilio, Felipe. "Composição e diversidade de taxocenoses de aves de rapina diurnas de paisagens abertas da savana uruguaia e floresta úmida com araucária." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/72305.

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As aves de rapina, como predadores de níveis superiores na rede trófica, necessitam de grandes áreas de vida e ocorrem em baixa densidade populacional. São sensíveis a alteração e degradação do habitat, sendo bons indicadores de qualidade de habitat e biodiversidade. Apesar da importância ecológica pouco se conhece sobre a biologia e ecologia da maioria das 91 espécies que ocorrem na América do Sul, o que nos leva ao objetivo mais amplo desta tese: descrever a composição das taxocenoses de aves de rapina dos campos do sul do Brasil e Uruguai e sua relação com as características topográficas e

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Bessey, Cindy. "The Role of Teleost Grazers in a Relatively Pristine Seagrass Ecosystem." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/911.

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Trophic downgrading of ecosystems necessitates a functional understanding of trophic cascades. Identifying the presence of cascades, and the mechanisms through which they occur, is particularly important for seagrass meadows, which are among the most threatened ecosystems on Earth. Shark Bay, Western Australia provides a model system to investigate the potential importance of top-down effects in a relatively pristine seagrass ecosystem. The role of megagrazers in the Shark Bay system has been previously investigated, but the role of macrograzers (i.e., teleosts), and their importance relative

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Trystram, Clément. "Écologie trophique de poissons prédateurs et contribution à l'étude des réseaux trophiques marins aux abords de La Réunion." Thesis, La Réunion, 2016. http://www.theses.fr/2016LARE0032/document.

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L'objectif général de cette thèse est d'étudier les relations alimentaires entre différents prédateurs d'intérêt local, appartenant à plusieurs compartiments écologiques. L'échantillonnage, réalisé entre janvier 2012 et décembre 2014 en partenariat avec la filière pêche, s'est concentré sur les principales espèces d'intérêt commercial ou en interactions avec les pêcheries (captures accessoires et déprédateurs). La détermination des sources de matière organique dont elles dépendent, de leurs relations interspécifiques, ainsi que des facteurs de variation de leurs alimentations, a été réalisée g

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Thiers, Laurie. "Utilisation des prédateurs supérieurs pour déterminer les zones d'importance pour la biodiversité : comparaison de différentes méthodes de mise en évidence de "hotspots"." Thesis, La Rochelle, 2014. http://www.theses.fr/2014LAROS025/document.

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Les nombreuses menaces qui pèsent sur le milieu marin et les preuves d’une perte de biodiversité globale au cours des dernières décennies ont rendu indispensable la mise en place de mesures de conservation dans les années à venir. Au sein des Terres Australes et Antarctiques Françaises (TAAFs) en particulier, qui offrent une biodiversité exceptionnelle et sont le cadre d’activités anthropiques intensives à travers les grandes pêcheries industrielles, la délimitation d’Aires Marines Protégées (AMP) serait extrêmement bénéfique pour la conservation du milieu. Pour définir les zones d’importance

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Compte, Ciurana Jordi. "Food webs of Mediterranean coastal wetlands." Doctoral thesis, Universitat de Girona, 2010. http://hdl.handle.net/10803/7879.

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En aquesta tesi doctoral s'han estudiat els efectes directes i indirectes de dos tipus d'espècies claus de la comunitat aquàtica dels aiguamolls de l'Empordà (aiguamolls costaners mediterranis amb una xarxa tròfica senzilla). S'han realitzat experiments al camp utilitzant microcosmos i mesocosmos i els resultats han estat analitzats mitjançant tres aproximacions: la taxonòmica, la funcional i la de mides. S'ha comprovat que en situacions amb absència de predadors i dominància d'una única espècie en el zooplàncton (en aquest cas Calanipeda aquaedulcis i Daphnia magna), la segregació del recurs

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Aubail, Aurore. "Étude des variations spatiales et temporelles du mercure en Arctique : utilisation des dents et des poils des prédateurs supérieurs comme tissus de biomonitoring." Phd thesis, Université de La Rochelle, 2010. http://tel.archives-ouvertes.fr/tel-00583122.

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Les tendances spatiales et temporelles du mercure en Arctique ont été étudiées au travers de l'analyse de ce métal dans les tissus durs, i.e. dents et poils, des phoques annelés (Phoca hispida) et des ours polaires (Ursus maritimus). Aucune influence du sexe sur les concentrations n'a été détectée dans les tissus de ces deux espèces alors que l'âge est apparu comme un facteur d'influence important.Deux tendances spatiales ont été observées dans les tissus de ces deux espèces : un premier gradient d'augmentation du mercure de l'Est vers l'Ouest de l'Arctique, i.e. de Svalbard, vers le Groenland

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Ferreira, Marco Alexandre Morgado Frade. "European catfish (Silurus glanis) movements and diet ecology in a newly established population in the Tagus drainage." Master's thesis, 2019. http://hdl.handle.net/10451/40493.

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Tese de mestrado, Biologia da Conservação, Universidade de Lisboa, Faculdade de Ciências, 2019<br>As invasões biológicas são uma das principais causas da perda de biodiversidade à escala mundial. O fenómeno da introdução de espécies afeta quase todos os ecossistemas. Os ecossistemas de água doce são altamente biodiversos, contendo cerca de 50% das espécies de peixe conhecidas e sendo vitais para o desenvolvimento da sociedade. No entanto, estão sob tremenda pressão, entre as consequências das alterações climáticas, da poluição, e regulação dos sistemas fluviais (e.g. barragens) que os deixaram

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Romero, Joana. "Diet and trophic relationships of top predators in the oceanic region of the archipelago of Madeira." Doctoral thesis, 2020. http://hdl.handle.net/10451/49741.

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Os estudos de dieta são um elemento importante na compreensão da ecologia de uma espécie, mas são muitas vezes negligenciados e a sua importância subestimada. A dieta de um organismo permite conhecer o habitat em que o animal vive e as suas adaptações ao meio ambiente, mas também permite saber sobre interações com outras espécies. É a combinação de estudos de dieta de várias espécies que permite construir cadeias alimentares e compreender a estrutura e o funcionamento dos ecossistemas. A aplicação deste tipo de estudos no meio marinho tem importância acrescida, uma vez que estudos baseados em

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Torres, Leigh Gabriela. "Top Predator Distribution and Foraging Ecology in Florida Bay, Florida." Diss., 2007. http://hdl.handle.net/10161/449.

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The heterogeneous landscape of Florida Bay provides habitats for a variety of predators and prey. This dissertation examined the bottom-up transfer of affects from environmental variability through prey composition up to competition and predation affects on top predator distribution and foraging ecology in Florida Bay. Line transect surveys for bottlenose dolphins and seabirds were conducted in Florida Bay during the summer months of 2002 - 2005. Photo-identification techniques were implemented to identify individual dolphins. Synoptic with this survey effort, habitat characteristics (temperat

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Torres, Leigh G. "Top Predator Distribution and Foraging Ecology in Florida Bay, Florida." Diss., 2007. http://hdl.handle.net/10161/449.

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Wong, Sarah Nuk Ping. "A pelagic paradox: the ecology of a top predator in an oceanic desert." 2012. http://hdl.handle.net/10222/15865.

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Sperm whales (Physeter macrocephalus) are widely distributed in all oceans, but principally found in areas of high primary productivity. Historically, they were whaled extensively in the Sargasso Sea and recent surveys have also found large numbers there. However, the Sargasso Sea is an oceanic gyre considered to be low in productivity. This dissertation explores the paradox of a high abundance of large top predators in a body of water once described as an “oceanic desert”. First, I compared the diet of sperm whales in the Sargasso Sea to those off Dominica, in the eastern Caribbean. Results s

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Silva, Inês Machado Bota da. "Ecological value of top predators and the case study of blue shark." Master's thesis, 2021. http://hdl.handle.net/10773/30813.

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Top predators have an important role in the trophic chain, especially in marine ecosystems, where the hypothesis that pristine biomass pyramids are inverted and therefore, with a more pronounced top-down control, is highly debated. Their abundance, however, have showed a marked decline over the years, due to exploitation and human-predator conflicts. Currently, a better appreciation of the importance of the relationships between species, have pushed areas like fishery research, to look at ecosystem-based management, with multispecies management strategies. Sharks are notorious pred

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Faria, Joana Sofia Costa Neves Pais de. "Using a seabird top predator to assess the adequacy of the Berlengas Marine Protected Area." Master's thesis, 2014. http://hdl.handle.net/10316/31140.

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Dissertação de mestrado em Ecologia, apresentada ao Departamento de Ciências da Vida da Faculdade de Ciências e Tecnologia da Universidade de Coimbra.<br>Os ecossistemas marinhos têm vindo a enfrentar um aumento no número de ameaças como a exploração insustentável dos recursos marinhos (por exemplo a pesca excessiva), degradação e perda de habitats marinhos, efeitos da poluição, da introdução de espécies invasoras e efeitos das alterações climáticas. Uma possível forma de diminuir tais impactos é através da implementação de Áreas Marinhas Protegidas (Marine Protected Areas, MPAs), que desempen

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LaBrecque, Erin. "Spatial Relationships among Hydroacoustic, Hydrographic and Top Predator Patterns: Cetacean Distributions in the Mid-Atlantic Bight." Diss., 2016. http://hdl.handle.net/10161/12277.

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<p>Effective conservation and management of top predators requires a comprehensive understanding of their distributions and of the underlying biological and physical processes that affect these distributions. The Mid-Atlantic Bight shelf break system is a dynamic and productive region where at least 32 species of cetaceans have been recorded through various systematic and opportunistic marine mammal surveys from the 1970s through 2012. My dissertation characterizes the spatial distribution and habitat of cetaceans in the Mid-Atlantic Bight shelf break system by utilizing marine mammal line-tra

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ŠMEJKAL, Marek. "Ecology of top fish predators, European catfish and asp, with consequences to fish communities." Doctoral thesis, 2017. http://www.nusl.cz/ntk/nusl-364706.

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The dissertation thesis focuses on predator ecology in artificial water bodies. Paper I deals with the importance of chemical cues for predator-prey interactions in an aquatic environment. Here, I demonstrate that the ability to detect chemical cues represents a survival benefit for prey species. Paper II points out gillnet methodological bias, which may have subsequent repercussions in field evaluation of a predator's presence and assessment of larger fish abundance in general. Papers III and IV focus on asp Leuciscus aspius spawning grounds. In Paper III, I demonstrate how males maximize the

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