Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2017-10-24T12:02:02Z No. of bitstreams: 1 PDF - Caroline Stefani da Silva Lima.pdf: 28204729 bytes, checksum: 5920971cb50b706bf8d83a493437825f (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2017-10-26T16:55:24Z (GMT) No. of bitstreams: 1 PDF - Caroline Stefani da Silva Lima.pdf: 28204729 bytes, checksum: 5920971cb50b706bf8d83a493437825f (MD5) / Made available in DSpace on 2017-10-26T16:55:24Z (GMT). No. of bitstreams: 1 PDF - Caroline Stefani da Silva Lima.pdf: 28204729 bytes, checksum: 5920971cb50b706bf8d83a493437825f (MD5) Previous issue date: 2017-02-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Estuaries are dynamic coastal ecosystems in which the interaction between the hydrological regime and the mixing of fresh and oceanic waters creates a gradient of variables that reflect on the structure of the fish community, as well as their spatio- temporal pattern. These characteristics are used as filters, that is, determining factors that select species ecologically similar, hence producing different groups of species along an environmental gradient. These filters can act on hierarchical scales, partitioning the diversity of species within the components α (local diversity), β (variation of diversity between sites) and γ (regional diversity). Therefore, the aim of this study was to analyze the composition, structure, hierarchical partitioning and if beta diversity is determined either by turnover or nestedness of fish assemblages in the Mamanguape river estuary, influenced by hydrological changes (rainy and dry periods). The composition and structure of the estuarine fish assemblages were characterized by a few dominant species in numerical abundance and biomass, being these considered core species. In addition, abundance and diversity increased with the proximity to the ocean due to adequate salinity conditions and greater habitat availability in these areas. The catch of fish in the estuary was higher during the rainy season, related to the recruitment period of many species that coincide with the environmental changes. The Canonical Correspondence Analysis indicated salinity and chlorophyll-a as the main filters of the spatial distribution of fish assemblages, separating them along the three zones according to the osmoregulation capacity of each species and the availability of resources in the zones. In the analysis of the hierarchical partition of the fish assemblages, the dissimilarity of the species composition was higher in the upper level (β3), influenced mainly by the turnover in both hydrological periods, suggesting the importance of the environmental heterogeneity for the fish diversity in this estuary. / Estuários são ecossistemas costeiros dinâmicos cuja interação entre o regime hidrológico, entrada de água doces e oceânica cria um gradiente de variáveis ambientais que refletem na estrutura da comunidade de peixes, bem como no seu padrão de utilização espaço-temporal. Estas características ambientais podem atuar como filtros, ou seja, fatores determinantes que selecionam espécies ecologicamente similares, consequentemente produzindo diferentes grupos de espécies ao longo de um gradiente ambiental. Tais filtros podem agir em escalas hierárquicas, particionando a diversidade de espécies dentro dos componentes α (diversidade local), β (variação da diversidade entre locais) a γ (diversidade regional). Portanto, o objetivo desse estudo foi analisar a composição, estrutura, bem como, partição hierárquica e se diversidade β das assembleias de peixes é determinada por turnover ou aninhamento no estuário do rio Mamanguape – PB, influenciada pelas mudanças hidrológicas (período chuvoso e seco). A composição e estrutura das assembleias de peixes estuarinas foram representadas por poucas espécies dominantes em abundância numérica e biomassa, sendo essas considerada core species. Além disso, a abundância e diversidade aumentaram com a proximidade com o oceano, devido às condições adequadas de salinidade e maior disponibilidade de habitats nestas áreas. A captura de peixes no estuário foi maior durante o período chuvoso, relacionadas ao período de recrutamento de muitas espécies que coincidem com as mudanças ambientais. A análise de correspondência canônica indicou a salinidade e a clorofila-a como os principais filtros da distribuição espacial das assembleias de peixes, separando-as ao longo das três zonas em função da capacidade de osmorregulação de cada espécie e a disponibilidade de recursos nas zonas. Na análise da partição hierárquica das assembleias de peixes, a dissimilaridade da composição de espécies foi maior no nível superior (β), influenciada principalmente pelo turnover em ambos os períodos hidrológicos, sugerindo a importância da heterogeneidade ambiental para a diversidade de peixes nesse estuário.

Submitted by Haroudo Xavier Filho (haroudo.xavierfo@ufpe.br) on 2016-08-30T18:08:06Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação (Anderson Rodrigues).pdf: 1100092 bytes, checksum: 006b7ba8f56e81d9066bc271f99edcbe (MD5) / Made available in DSpace on 2016-08-30T18:08:06Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação (Anderson Rodrigues).pdf: 1100092 bytes, checksum: 006b7ba8f56e81d9066bc271f99edcbe (MD5) Previous issue date: 2016-02-17 / FACEPE / A perda da diversidade biológica pode ser um reflexo da degradação ambiental, principalmente em locais com grandes contingentes demográficos. No Nordeste do Brasil, a maioria das regiões metropolitanas estão concentradas em zonas costeiras, ocasionando a liberação de uma grande quantidade de poluentes e ameaçando a sobrevivência de inúmeras espécies, como os peixes. Neste estudo, tentamos avaliar possíveis danos no DNA em um dos recursos pesqueiros mais consumidos pelas comunidades ribeirinhas nesta região, a tainha (Mugil curema). Metodologias de Ensaio Cometa (EC) e Teste do Micronúcleo (MN) foram utilizadas em populações desta espécie, provenientes de cinco estuários Pernambucanos (rios Goiana e Jaguaribe no litoral Norte), (rios Sirinhaém e Formoso no litoral Sul) e (rio Capibaribe na região metropolitana). Para fins de comparação, uma amostra controle foi coletada no estuário do Rio Una (local de preservação ambiental), litoral sul do estado de São Paulo. Nossos resultados mostram que o estuário mais afastado da região metropolitana, o Rio Formoso, quando comparado ao grupo controle, foi quem apresentou os menores níveis de danificação genômica (P >0,05). Já os demais estuários apresentaram níveis elevados de danificação quando comparados ao controle (P < 0,05). Em especial, o estuário do rio Capibaribe, localizado na capital Pernambucana, foi aquele que apresentou um dos maiores níveis de dano genômico (P = 0,0001). Tais dados caracterizam-no como o mais impactado entre os cinco avaliados. Estes dados também apontam para uma forte associação entre níveis elevados de danificação genômica (macro e microlesões no DNA) em locais próximos a grandes contingentes demográficos e industriais. Consequentemente, este cenário de impactação pode também estar afetando a comunidade biótica como um todo, incluindo as comunidades humanas ribeirinhas que tem este recurso como forma de subsistência. Estes resultados demonstram a efetividade do uso de metodologias de EC e MN como protocolos rápidos e precisos na avaliação de ecossistemas marinhos, principalmente em regiões fortemente impactadas pelas atividades antrópicas. / The loss of biological diversity may be a reflection of environmental degradation, especially in places with large demographic contingents. In northeastern Brazil, most metropolitan regions are concentrated in coastal areas, causing the release of large amounts of pollutants and threatening the survival of many species, such as fish. In this study, we attempt to assess possible damage to the DNA in one of the most consumed fish resources by coastal communities in this region, mullet (Mugil curema). Methodologies comet assay (EC) and micronucleus test (MN) were used in populations of this species, from five Pernambucanos estuaries (Goiana and Jaguaribe rivers in the northern coast), (Sirinhaém and Formoso rivers in the south coast) and (Capibariberiver in Metropolitan region). For comparison purposes, a control sample was collected in the estuary of the Una River (local environmental preservation), southern coast of São Paulo. Our results show that the far estuary in the metropolitan area, the Formoso River, when compared to the control group, was the one who had the lowest levels of genomic damage (P> 0.05). None of the other estuaries showed elevated levels of damage compared to the control (P <0.05). In particular, the estuary of the river Capibaribe, located in Pernambuco capital, was the one who presented one of the highest levels of genomic damage (P = 0.0001). These data characterize it as the most affected among the five evaluated. These data also point to a strong association between high levels of genomic damage (macro and micro-lesions in DNA) in locations near major demographic and industrial contingent. Consequently, this scenario impaction may also be affecting the biotic community as a whole, including the riparian human communities that have this feature as a means of subsistence. These results demonstrate the effectiveness of using EC and MN methodologies as fast and accurate protocols in evaluating marine ecosystems, particularly in regions heavily impacted by human activities.

A distribuiÃÃo dos organismos em relaÃÃo ao seu habitat à de importÃncia central para a ecologia. A natureza dessa distribuiÃÃo fornece visÃo inicial sobre os tipos de processos ecolÃgicos que regulam as assemblÃias e populaÃÃes. O presente trabalho tem como objetivo caracterizar e comparar a estrutura da macrofauna bentÃnica, correlacionando-a com as condiÃÃes ambientais de bancos arenolamosos nos estuÃrios dos rios Pacoti e Pirangi, CearÃ. Em fevereiro de 2005, foram coletadas 45 amostras em cada estuÃrio e preservadas em formol, lavadas em Ãgua corrente, coradas com rosa bengala, triadas com o auxÃlio de microscÃpio eletrÃnico e os organismos identificados ao menor nÃvel taxonÃmico possÃvel. Os parÃmetros temperatura, matÃria orgÃnica, CaCO3, cascalho, areia e finos apresentaram diferenÃas significativas (p<0,05) entre os dois estuÃrios. No Pacoti, a espÃcie Laeonereis culveri (Annelida: Polychaeta) apresentou maior densidade (10422,98 ind/m2) e, no Pirangi, Tagelus plebeius (Mollusca: Bivalvia) com 910,35 ind/m2. A anÃlise apontou forte correlaÃÃo negativa entre a abundÃncia mÃdia com a matÃria orgÃnica e argila no estuÃrio do Pirangi e uma forte correlaÃÃo positiva entre a riqueza com mÃdia do grÃo, matÃria orgÃnica, silte e correlaÃÃo negativa com a areia no estuÃrio do rio Pacoti. A abundÃncia mÃdia foi mais elevada no Pacoti, porÃm riqueza, equitabilidade e diversidade foram mais elevadas no rio Pirangi. No rio Pacoti, a anÃlise de agrupamento revelou um banco areno-lamoso altamente homogÃneo, com elevado grau de similaridade entre os pontos. Jà o Pirangi mostrou-se mais heterogÃneo com menor grau de similaridade. A anÃlise do BIOENV discriminou seleÃÃo do grÃo, carbonato de cÃlcio e teor de matÃria orgÃnica como os fatores abiÃticos que melhor explicaram a estrutura da macrofauna bentÃnica do banco areno-lamoso do rio Pacoti e a porcentagem de cascalho e de finos no banco areno-lamoso do rio Pirangi. / The distribution of organisms regarding their habitat plays an important role in ecological studies. The nature of this distribution provides an initial view on the types of ecological processes regulating the assemblages and the populations. The present study aims to characterize and to compare the benthic macroinfauna community structure, correlating it with the environmental conditions at the muddysand flats at the Pacoti and the Pirangi estuaries. In February 2005, 45 samples were collected in each estuary, sample were preserved in formol, passed through a 0,3mm mesh, dyed with rose, sorted and the organisms identified. The amount of shingle, sand, silt, and clay presented significant differences (p<0,05) between the two estuaries. At Pacoti estuary, Laeonereis culveri presented the highest density (10,423 ind/m2) and, at Pirangi estuary, Tagelus plebeius was the dominant species with a density of 910.35 ind/m2. Analysis pointed out a strong negative correlation between the average abundance and the organic matter, and between the average abundance and clay at the Pirangi estuary. At the Pacoti estuary, a strong positive correlation was observed out between the richness and several parameters such as the mean grain size, organic matter, and silt. A negative correlation between the richness and the amount of sand was also evidenced at the same estuary. The average abundance was higher at Pacoti, whereas richness, equitability, and diversity were higher at Pirangi. At the Pacoti estuary, the cluster analysis revealed a highly homogeneous muddy-sand flat, with strong similarity among samples. On the other hand, Pirangi was more heterogeneous with a lower similarity degree. The BIOENV analysis discriminated grain selection, CaCO3, and the amount of organic matter as the abiotic factors that best explain the structure of benthic macroinfauna communitâs in the muddy-sand flat at Pacoti. At the Pirangi estuary, the relevant abiotic factors were the shingle and fine sediment percentage.

The spatial and temporal pattern of ichthyofaunal community composition in relation to selected physico-chemical (temperature and salinity) and biological variables (chlorophyll-a and zooplankton) was investigated at ten stations in the temperate temporarily open/closed Kasouga estuary. In addition, the food web structure in the estuary was investigated using stable carbon isotope analysis. Results of the 5 metre seine net survey indicated that ichthyofaunal composition and biomass in the Kasouga estuary was largely determined by seasonality and mouth condition. Maximum abundance and biomass of ichthyofauna was recorded during summer or during those periods when overtopping occurred. Overtopping coincided with the recruitment of marine estuarine dependant species, which dominated the catches both numerically and in biomass. The recruitment of these species resulted in an increase in diversity of the ichthyofaunal community. There were no significant spatial patterns in the distribution of smaller ichthyofauna (<50mm SL) identified in Bray-Curtis similarity matrices using cluster analysis (Primer 5 v5.2.4). Spearman’s correlation analysis revealed that there were no significant correlations between abundance and biomass of ichthyofauna and selected physico-chemical and biological variables other than salinity (P>0.05 in all other cases). There were two distinct spatial patterns in the distribution of the larger ichthyofauna (>50mm SL). These corresponded to a grouping associated with the mouth region and a grouping associated with the remaining regions of the estuary. Stable isotope analysis indicated that the primary source of carbon utilised by the ichthyofauna of the Kasouga estuary was derived from the channel, most likely microphytobenthic algae. The contributions of the riparian and salt marsh vegetation to the total carbon flow appear to be minimal.

The release of nutrients (nitrogen and phosphorus) via land clearing, application of fertilisers, discharge of human waste and combustion of fossil fuels, is one of the most harmful effects of anthropogenic stresses on aquatic environments. This study investigated the use of reeds as indicators of nutrient input to estuaries. Small estuaries such as the oligotrophic East Kleinemonde where the research was mostly conducted are sensitive to nutrient enrichment from septic tanks, stormwater runoff and fertiliser application to lawns in close proximity to the estuary. Nutrient concentrations were sampled at different positions, in the groundwater, at the water’s edge, in the reed bed and in the main estuary channel at five sites in the East Kleinemonde Estuary. The NH4+ and SRP concentrations showed a definite trend as concentrations decreased from the groundwater or water’s edge into the main estuary channel. Groundwater introduced nutrients to the estuary which were then taken up by the fringing reeds (Phragmites australis (Cavinelles) Trinius ex Steudel). The water column nutrients were either below detectable limits or in very low concentrations. Low TOxN concentrations were consistently found at the different sites and probably resulted from P. australis assimilating N-TOxN for growth more efficiently than N- NH4+. The roots, rhizomes, stems and leaves of the reeds were measured for δ15N as an indicator of nutrient enrichment as nitrogen stable isotope analysis of plant tissue is an effective method for assessing and monitoring septic tank and other anthropogenic inputs. All plant parts for the three sampling sessions at Site 1 (mouth region) in the East Kleinemonde Estuary had significantly higher δ15N signatures (~20 percent) than the leaves at Site 5 (upper reaches). These differences were related to the surrounding land-use of the East Kleinemonde catchment, where the lower part of the estuary has moderate to low residential development and the upper reaches are utilized mainly for livestock farming. The high δ15N signatures at Site 1 were attributed to septic tank wastewater and stormwater run-off entering the estuary. Nutrient enrichment also influenced the morphology of the reeds. Reed biomass, height and stem density was significantly higher at Site 1 compared to Site 5. Similar studies were conducted in August 2008 in the Sundays Estuary and October 2008 in the nearby Mtati and Mpekweni estuaries to see if the results were similar. iii The same patterns were found where the groundwater NH4+ and SRP concentrations were higher than the estuary channel in the Mtati and Mpekweni estuaries. In the Mpekweni and Sundays estuaries Phragmites australis leaves had high δ15N signatures (10 and 11 percent) similar to that of Site 1 in the East Kleinemonde Estuary. Lower signatures (-2 to +4 percent) were found in the Mtati Estuary. This sampling site was sheltered by a bridge with a steep slope and the concentrations were similar to Site 3 and 5 in the East Kleinemonde Estuary where the derived nutrient was the result of stormwater runoff or fertilisers. Density and biomass of reeds in the Sundays and East Kleinemonde (Site 1) estuaries were similar and this could be related to different nutrient sources, agricultural return flow and septic tank input respectively. Reeds in the Sundays Estuary were significantly taller than in the other estuaries which showed that factors such as shelter and salinity also influence reed growth and therefore morphology alone would not be a good indicator of nutrient enrichment. Indicators of nutrient enrichment are important as the status of temporarily open / closed estuaries in South Africa is threatened by deteriorating water quality. Measurements of the water column may provide an inaccurate assessment of water quality whereas macrophytes are outstanding potential indicators of nutrient enrichment as they are widely distributed, abundant and long-lived. The findings from this study indicate that δ15N concentrations in reeds can be used to indicate nutrient loading.

Two pocket sandy beaches, Eastern Cape, South Africa, were investigated, to determine whether these beaches were subsidised by an adjacent mangrove estuary, by using stable light isotope (δ 13C and δ 15N) analyses. The trophodynamics and macrofaunal food webs of these two beaches, situated between the Mgazi and Mgazana estuaries (in a warm-temperate/subtropical transition zone,), were described. Two to 2.5 trophic levels were identified for the macrobenthic community, with suspension feeders and omnivorous scavengers as the primary consumers, and carnivores as the secondary consumers. Mangrove material and terrigenous inputs were not driving the sandy beach food webs. Instead, marine allochthonous inputs (carrion, macroalgae), possibly phytoplankton, sediment organic matter, and resident macroinfauna were the dominant food sources. Cattle dung could have been the only important terrigenous food source utilised by the beach benthos. The macroinfauna displayed generalist/omnivorous feeding strategies, but within the limits of predominantly marine food sources. There was evidence that carnivores actively preyed on resident beach fauna. Omnivory and intraguild feeding might also be important biological processes in these communities. Seasonal and spatial variability in stable isotope composition of the fauna was observed, but few patterns were evident. There was a general trend of more enriched δ 15N and δ 13C composition of animal tissues in summer as opposed to winter. This was accompanied by a general decrease in C:N ratios in summer. It was hypothesised that these isotopic and biochemical changes were in response to increased food availability during summer. Although mangrove material appeared not to play an important role in the nutrition of these sandy beach communities, it was suggested that a high retention time of particles in the bay could enhance bacterial decay of particulate mangrove material, which could then act as fine, bacterial-enriched particulate food to the macrobenthos. This remains to be tested.

The Mngazana and Mngazi estuaries are situated just south of Port St. Johns close to the biogeographical boundary between the warm temperate and subtropical zones along the east coast of Southern Africa. The Mngazana estuary is a permanently open estuary with three species of mangrove. The Mngazi estuary is a temporarily open/closed system. The ichthyofauna was sampled with seine nets and gillnets during June 2005, August 2005, November 2005, February 2006 and April 2006. The fish community structure was significantly different between the two estuaries with the differences being especially noticeable in the larger fish sampled with gillnets. There were significant differences in the fish community sampled with the seine net on both spatial and temporal scales in both of the estuaries. Certain warm temperate species were less abundant and certain subtropical species were more abundant at the Mngazana estuary than they were during a study conducted in 1975. Stomach content analysis revealed that most species had similar diets in the two estuaries with the only differences occurring among benthic feeding species. The diet of sub-adult piscivores comprised of a large proportion of penaeid prawns while the juveniles feed mainly on mysids. The zooplanktivorous fish feed mainly on copepods and mysids with the proportions varying between the species. Benthic feeding fishes showed the greatest variability in diet with plant material, detritus, crabs and copepods being the main food sources. Stable isotopes revealed that particulate organic matter and microphytobenthos were the most important carbon sources to fish in the Mngazi estuary. In the Mngazana estuary a combination of mangrove material, detritus, particulate organic matter and Zostera material were the most important carbon sources. The importance of each of these sources did, however, vary greatly between the different trophic guilds of the fish in the Mngazana estuary. The distribution of certain fish species was investigated in relation to physical parameters (temperature, salinity, turbidity and depth) and biological parameters (prey and predators) in the environment. It was found that most small fish (< 100 mm SL) were strongly correlated with turbidity where-as they showed weak correlations with their prey. Sub-adult piscivores fell into two groups, i.e. those that could tolerate turbid water and those that were only found in clear water. The group that also occurred in turbid water showed very strong correlations with their prey but the clear water group did not. It would appear that the small and thus vulnerable fish seemed to occur in areas that offered them protection rather than areas where their food supply is most abundant, where-as the piscivores were more influenced by prey distribution, as long as the physical conditions were tolerable to them.

Les PCB (polychlorobiphényles), PBDE (éthers de biphényles polybromés) et OCP (pesticides organochlorés) sont des composés d’origine anthropique classés comme POP (polluants organiques persistants) dont l’usage a progressivement été restreint ou interdit. Ces composés, de par leur caractère ubiquiste, persistant et bioaccumulable, sont néanmoins toujours présents dans l’environnement, d’où l’importance de continuer à étudier leur présence, leur dynamique et leur impact. Du fait de la restriction de leurs usages, d’autres composés sont maintenant utilisés pour les remplacer, tels que les retardateurs de flamme alternatifs (RFA). Ces composés bromés et chlorés ont des propriétés physico-chimiques comparables à celles des POP précités et peuvent potentiellement constituer un danger chimique pour l’environnement. Par ailleurs, les RFA sont attendus à des niveaux de concentration plus faibles que les PCB et les PBDE que ce soit dans les compartiments biotiques et abiotiques. Ainsi, l’un des enjeux de ce travail de thèse était de développer une méthode multi-résidus, associant chromatographie en phase gazeuse et spectrométrie de masse à temps de vol, permettant d’analyser simultanément 17 RFA à des niveaux inférieurs au ng.g-1. Les niveaux et profils de contamination en POP et RFA ont ensuite été renseignés dans les compartiments biotiques et abiotiques de différents systèmes aquatiques contrastés. Le caractère bioamplifiable de ces composés a été étudié grâce à la détermination de facteurs d’amplification trophique (TMF) dans l’estuaire de la Gironde et dans le bassin du Rhône, à l’aide d’outils statistiques innovants. Dans l’estuaire de la Gironde il a été mis en évidence que certains RFA étaient autant voire plus bioamplifiables que certains POP historiques. Par ailleurs, dans le bassin du Rhône, l’utilisation des TMF comme outil prédictif, pour le BDE-47 ou la ΣPBDE-DCE par exemple, a été discutée et parait envisageable dans un cadre réglementaire. / PCBs (polychlorinated biphenyls), PBDEs (polybrominated biphenyl ethers) and OCPs (organochlorine pesticides) are anthropogenic compounds classified as POPs (Persistent Organic Pollutants), their use was restricted or prohibited. These compounds are ubiquitous, persistent and bioaccumulative and they are still present in the environment; this is the reason why it is important to continue the study of the fate and impact in the environment. Due to their usage restriction, other compounds are now used to replace them, such as alternative flame retardants (RFAs). These brominated and chlorinated compounds have physicochemical properties comparable to those of POPs and can thus be potentially hazardous to the environment. In addition, RFAs are expected to occur at lower concentrations than PCBs and PBDEs, whether in the biotic and abiotic compartments. Thus, one of the challenges of the present work was to develop a multiresidue method, based on gas chromatography coupled with a time-of-flight mass spectrometer, allowing for the simultaneous analysis of 17 RFAs at levels below ng.g-1. The levels and patterns of POP and RFA contamination were reported in the biotic and abiotic compartments of selected hydrosystems. The biomagnification potential of these compounds was also studied by determining trophic magnification factors (TMF) in the Gironde estuary and in the Rhône basin. In the Gironde estuary, it was shown that some RFA biomagnify as much or more than some historical POPs. Furthermore, in the Rhône basin, the use of TMF for predictive purpose, for BDE-47 or ΣPBDEs-WFD for example, was discussed and found possible.

Many migratory shorebirds rely on estuaries as stop-over sites to refuel during migration, and the loss of stop-over sites is a primary threat to shorebird populations on the West Coast of the United States (e.g. Calidris alpina pacifica, C. mauri). Conservation and research has focused on the largest of these sites; however, smaller estuaries also host thousands of migratory shorebirds. Furthermore, the reasons for site selection are largely unknown. Estuarine inter-tidal microhabitats are non-uniform and both abiotic and biotic factors may serve as predictors of whether an abundance of shorebirds will use a site. I investigated shorebird site selection on broad and fine scales within Oregon estuaries. To identify factors that relate to shorebird abundance on large spatial scales, I compiled shorebird abundance data from estuaries throughout the Pacific Northwest as well as data on site quality factors. To investigate site selection on a finer scale I measured shorebird abundance, habitat characteristics, and food resources―invertebrates and a newly considered source, biofilm―within two Oregon estuaries during the fall migration period. Finally, I examined whether channels are preferentially used by foraging Calidrid shorebirds by conducting observations during the spring migration. I investigated whether channels may be superior foraging habitat possibly because prey are more abundant, are found at shallower depths, or because sediments are more penetrable (increasing the opportunity for shorebird probing) by taking infauna cores and measuring force required to probe in the sediment at channel and open mudflat sites. Among estuaries, shorebird densities in spring were best predicted by estuary size, as opposed to the amount of any one habitat. During fall migration, the amount of grassland in the surrounding watershed was also a good predictor, pointing to the probable importance of roost sites as well as feeding grounds. The amount of infauna also related to the density of shorebirds using a site. Within estuaries, shorebird distribution in the inter-tidal region was not generally predicted by prey abundance. Channels were used preferentially by shorebirds, and infauna abundance along channels was greater than in the surrounding mudflats. The more penetrable sediments of the channel also made it easier for shorebirds to probe and capture prey. Identification of these large-scale and fine-scale factors that influence site quality for migratory shorebirds will assist land and wildlife managers' efforts to protect these species.

Made available in DSpace on 2014-12-17T15:42:07Z (GMT). No. of bitstreams: 1 George Queiroz de Brito_DISSERT.PDF: 4768865 bytes, checksum: 4923b44db97f60fb6edf6bd685c61440 (MD5) Previous issue date: 2010-02-26 / This work examined the possibility of using mussel Mytella falcata as bioindicator sample to detect metal ions in several estuaries potiguares, since species substances that accumulate in their tissues due to its characteristics filter feeders have been used for environmental monitoring. The chemometrics by principal components analysis was used to reduce the size of the original data in order to establish a pattern of distribution of metal ion. Samples were collected at three different points in the estuaries Curimata?, Guara?ra-Papeba, Potengi, Galinhos-Guamar? and Piranhas-Assu having been marked with the location using GPS (Global Positioning System). The determination of humidity content and digestion of the samples were performed using methods described in the Compendium of analytical standards of the Institute Adofo Lutz (2005) and the determination of metal ions of the elements Al, Ba, Cd, Cr, Cu, Mn, Ni, Pb, Sn and Zn were performed by optical emission spectrometry with inductively coupled plasma as described by USEPA method 6010C. The results show that it is possible to use this molluscum Mytella falcata in the estuaries of Rio Grande do Norte for the determination of metal ions. The data were subjected to principal components analysis (PCA) which enabled us to verify the distribution pattern of the metal ions studied in several estuaries potiguares and group them according to the metal ions in common with and relate them to the activities in each region / Este trabalho procurou verificar a possibilidade do uso do molusco bivalve Mytella falcata como amostra bioindicadora para detectar ?ons met?licos em v?rios estu?rios potiguares, pois as esp?cies que acumulam subst?ncias em seus tecidos devido as suas caracter?sticas filtradoras tem sido utilizadas para o monitoramento ambiental. A quimiometria atrav?s da an?lise de componentes principais foi utilizada para reduzir a dimens?o dos dados originais com a finalidade de estabelecer um padr?o de distribui??o dos ?ons met?licos estudados. As amostras foram coletadas em tr?s pontos diferentes nos estu?rios Curimata?, Guara?ra-Papeba, Potengi, Galinhos-Guamar? e Piranhas-Assu tendo o local sido marcado com a utiliza??o de GPS (Global Positioning System). A determina??o do teor de umidade e a digest?o das amostras foram realizadas segundo metodologia descrita no comp?ndio de normas anal?ticas do Instituto Adofo Lutz (2005) e a determina??o dos ?ons met?licos dos elementos Al, Ba, Cd, Cr, Cu, Mn, Ni, Pb, Sn e Zn foram realizadas por espectrometria de emiss?o ?tica com plasma acoplado indutivamente como descrito pela metodologia USEPA 6010C. Os resultados obtidos mostram que ? poss?vel utilizar o molusco Mytella falcata presente nos estu?rios do Estado do Rio Grande do Norte para a determina??o de ?ons met?licos. Os dados foram submetidos ? an?lise de componentes principais (PCA) o que possibilitou verificarmos o padr?o de distribui??o dos ?ons met?licos estudados nos v?rios estu?rios potiguares e agrup?-los de acordo com os ?ons met?licos em comum e relacionar a presen?a com as atividades desenvolvidas em cada regi?o