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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

Benthic Macroinvertebrate Subsampling Effort and Taxonomic Resolution for Bioassessments of Streams in the James River Watershed of Virginia

Williams, Laurel 01 May 2014 (has links)
Benthic macroinvertebrate diversity influences stream food web dynamics, nutrient cycling and material exchange between the benthos and the water column. Stream bioassessment has moved to the forefront of water quality monitoring in terms of benthic macroinvertebrate diversity in the recent past. The objectives of this study were to determine optimum subsample size and level of taxonomic resolution necessary to accurately and precisely describe macroinvertebrate diversity in streams flowing in the Piedmont province of the James River watershed in Virginia. Forty-nine sampling sites were selected from streams within the Piedmont Physiographic Province of the James River watershed. Ten sites were randomly selected to have all macroinvertebrates in the sample identified to the genus level whenever possible. Optimum subsampling intensities and Virginia Stream Condition Index (VSCI) metrics and scores were determined. For samples with the total number of individuals at less than 500, the genus level of taxonomy provided lower overall optimum subsampling intensities. However, for samples with total individuals over 1000, optimum subsampling intensities at the genus level of taxonomy were higher than the family level for more than 50% of the metrics. For both family and genus levels of taxonomy, the majority of optimum subsampling intensities were well over 50% of the total individuals in the sample, with some as high as 100% of the individuals. While optimum subsampling intensities were valuable in comparing family and genus level taxonomy, they are not reasonable for stream bioassessment protocols; the cost:benefit ratio would be highly unbalanced. A minimum subsample size of 200 individuals is optimum for determining VSCI scores, while optimum taxonomic resolution is dependent on several factors. Thus, the level of taxonomic resolution for a particular study should be determined by the study objectives, level of site impairment and sample size.
192

Factors limiting benthic algal abundance in Virginia streams of the Coastal Plain

Brandt, Michael 24 July 2009 (has links)
Algae are important components of stream food webs and often used in biomonitoring assessments. Little is known regarding the factors that limit their abundance in streams of the VA Coastal Plain. The surficial geology of the Coastal Plain is predominately sandy deposits which comprise the dominant substrate in streams of this region. In a comparative study of five streams located near the VCU Rice Center, we quantified substrate composition, light availability, and nutrient concentrations to assess their relative importance in determining benthic algal abundance. The proportion of stream area comprised of hard substrates was a significant predictor of variation in benthic algal abundance (r²=0.66). An experimental component comparing algal colonization on artificial hard substrates (tile) to the natural substrate reinforced the importance of substrate stability. Hard substrates which included gravel and aggregated clay likely provided greater stability for algal colonization relative to sand and silt deposits, resulting in lower mortality from scouring and sedimentation. Incident solar radiation was a secondary factor affecting algal abundance with shaded streams exhibiting lower benthic chlorophyll. Where substrate and light conditions were favorable, relationships between benthic algal abundance and dissolved phosphorus concentrations were observed. Seasonal fluctuations were ameliorated by high light conditions and constant disturbances at sites lacking hard substrates which kept CHLa at consistently low levels. The mean proportion of FBOM C derived from benthic algae ranged from 10 to 24%. In spite of the consistently low observed benthic algal abundance at sandy unstable Coastal Plain streams, benthic algae are an important source of benthic organic matter.
193

Évolution et santé des herbiers à Zostera noltii dans le bassin d'Arcachon à travers la dynamique de la macrofaune benthique associée / Evolution and health of seagrass Zostera noltii in Arcachon bay through the dynamics of associated benthic macrofauna

Do, Van Tu 17 September 2012 (has links)
L’objectif général était d’évaluer la réponse du macrobenthos à la dynamique d’un herbier marin à Zostera noltii (colonisation, maturation, destruction, restauration), dans le Bassin d’Arcachon, une lagune du sud-ouest de la France. Quand l’herbier commence à se développer, la structure de la macrofaune diverge immédiatement entre habitats d’herbier et de sables nus, sans cependant que les indice biotiques testés (BENTIX, BOPA, AMBI) varient. De même, la population du bivalve dominant, la coque (Cerastoderma edule), souffre du développement de l’herbier. Sa communauté parasitaire (trématodes) est modifiée, sans que cela n’influe sur la dynamique des coques. A l’échelle du Bassin, le développement de l’herbier (considéré comme un signe de “bonne santé”) a été comparé à la santé de deux bivalves endogés dominants, la palourde japonaise (Ruditapes philippinarum) et la coque (C. edule), évaluée en termes de prévalence de maladie. Aucune corrélation n’existe entre le taux de recouvrement d’herbier et la prévalence de trois maladies (trématodiase, perkinsose, maladie du muscle marron). Entre 2002 et 2010, la surface d’herbier a diminué de 1/3. En termes de structure de communautés et d’espèces dominantes, peu de différences sont notées au sein de chaque année (entre les 12 stations) et entre années, indépendamment du déclin de l’herbier. Parmi les indicateurs biotiques, l’indice multivarié MISS est en adéquation avec la relative similarité de la structure de la macrofaune benthique entre les groupes discriminés par l’analyse MDS. En 2005, des activités de dragage dans le Bassin d’Arcachon ont abouti à l’enfouissement de 0,32 km2 d’herbier à Z. noltii. La structure du macrobenthos a été immédiatement modifiée sans retour à l’état initial sur les zones couvertes de sable. En revanche, le macrobenthos (endofaune) s’est rapidement rétabli dans les zones couvertes de vase alors que l’herbier n’a commencé à se développer qu’au bout de 5 ans après les travaux. Le dernier chapitre de cette thèse donne un bref aperçu des connaissances actuelles sur les herbiers vietnamiens et des possibles travaux scientifiques à mener. / The overall objective was to assess macrobenthos response to marine Zostera noltii seagrass dynamics (colonization, maturation, destruction, restoration), in Arcachon Bay, a French Southwestern lagoon.When seagrass starts to develop, the structure of macrofauna community immediately diverges between sand and seagrass habitats, without however modifying tested biotic indices (BENTIX, BOPA, AMBI). As well, population of the dominant bivalve, the cockle (Cerastoderma edule), suffers from seagrass development. Their parasite (trematode) community are impacted, but not sufficiently to explain cockle deficit in seagrass.At the scale of the Bay, seagrass development (considered as a sign of “good health”) is compared to the fitness of the two dominant infaunal bivalves, the Manila clam (Ruditapes philippinarum) and the cockle (Cerastoderma edule), measured in terms of disease prevalence. There was no correlation among seagrass cover rate and the prevalence of three diseases: trematodiosis, perkinsosis and Brown Muscle Disease.Between 2002 and 2010, seagrass cover decreased by 1/3. When looking at community structure and dominant species, there were moderate differences within (among 12 stations) and among years, independently of seagrass decline. Among biotic indicators, multivariate index MISS was in adequation with the relative similarity of macrofauna structure among groups discriminated by MISS analysis.In 2005, dredging activities in Arcachon Bay led in burying 0.32 km2 of Z. noltii. Macrobenthos structure was immediately modified and did not recover in places buried by sand. Conversely, macrobenthos (infauna) recovered rapidly in areas cover by mud, while seagrass began to develop again five years after work. The last chapter of the thesis provides a brief insight of the seagrass in Vietnam, the actual knowledge and what could be investigated.
194

An Alternate Trawling Method: Reduced Bycatch and Benthic Disturbance Achieved with the Wing Trawling System

Udoff, Geoffrey 13 May 2016 (has links)
The Wing Trawling System (WTS) was tested as an alternative to traditional shrimp capture methods in the Gulf. Compared to an otter trawl, this trawl was conceived to reduce bycatch, retain shrimp catch, and minimize seafloor disturbance. Through seventy-one paired tows, the WTS was assessed against a standard otter trawl. The WTS was found to reduce bycatch by 63-65% and reduce shrimp catch by 30-35%. Additionally, I measured the depth of the scars produced by both trawls and quantified the turbidity of the plumes behind them. The scars left by the WTS and the otter trawl were between 9.9 cm-13.6 cm. The turbidity behind the WTS was 18.6 NTU, while the turbidity behind the otter trawl was 206.8 NTU. In conclusion, the WTS offers an alternative to an otter trawl that reduces bycatch and the impact trawling has on the seafloor but results in a significant amount of shrimp loss.
195

Habitatets och funktionella gruppers respons ett år efter dammutrivning : Nianån och Gnarpsån / The response of the habitat and functional groups one year after dam removal : Nianån and Gnarpsån

Lindsten, Madeleine January 2019 (has links)
Dams are a typical example of how watercourses are being used, especially for production of electricity. Negative consequences that follows are that the character of the watercourse is altered, which in turn affects the composition of organisms. In the summer of 2017, a hydroelectric plant was removed in Nianån. A project started with the purpose to investigate the effects on benthic fauna, one year after the removal. In this study, the watercourse Gnarpsån was also used as a control. It was assumed that the proportion of silt and sand, as well as the water depth had decreased while the water velocity had increased in the habitat of the former reservoir in Nianån. It was also assumed that a change in the density of the benthic fauna should have occurred in Nianån, downstream in the riffle. The abundance of organisms with a burial lifestyle should have decreased in the habitat of the former reservoir, while the abundance of scrapers and filters should increase in the riffle. The result showed few significant physical changes. A difference in substrate composition could be seen in Nianån, however it was the proportion of fine substrates that increased in all habitats (gravel, fine gravel and sand). The water velocity was unchanged in Nianån, and the depth only decreased in the flowing habitat upstream. In both watercourses, 38 different families of macroinvertebrates were found. The proportion of burial animals in the habitat of the former reservoir decreased significantly, but no change in the total density was found. A possible effect may already have been recovered, or more time may need to pass before expected results can be seen. Many factors affect the conditions in the watercourses. To be able to provide better general predictions about the effects of dam removal, further studies are needed, both at the organism level and with a large-scale approach to get a uniform picture of this restoration measure. / Dammar är typiska exempel på hur vattendrag utnyttjas, framförallt för elproduktion. Negativa följder är att vattendragets karaktär förändras, vilket i sin tur påverkar sammansättningen av organismer. Sommaren 2017 togs ett kraftverk bort i Nianån. Ett projekt startade med syftet att undersöka effekterna på bentisk fauna ett år efter dammutrivningen. I denna studie används också vattendraget Gnarpsån som en kontroll. Det antogs att andelen silt och sand, samt vattendjupet hade minskat medan vattenhastigheten hade ökat i habitatet i den före detta regleringsdammen i Nianån. Det antogs även att en förändring av tätheten av bottenfauna borde ha skett i Nianån, nedströms i torrfåran. Andelen nedgrävande djur borde ha minskat i habitatet i den före detta regleringsdammen, medan andelen skrapare och filtrerare ökat i torrfåran. Resultatet visade på få signifikanta fysiska förändringar. En viss skillnad i substratsammansättning kunde ses i Nianån, dock var det andelen fint substrat som ökat i samtliga habitat (grus, fint grus och sand). Vattenhastigheten var oförändrad i Nianån, och djupet minskade endast i det strömmande habitatet uppströms. I vattendragen återfanns 38 olika familjer av makroevertebrater. Andelen nedgrävande djur i habitatet i den före detta regleringsdammen minskade signifikant, men någon förändring i total individtäthet påvisades inte. En eventuell effekt kan redan ha återhämtats, eller så behöver mer tid gå innan förväntade resultat kan ses. Många faktorer påverkar förhållandena i vattendragen. För att kunna ge bättre generella förutsägningar om effekter av dammutrivning behövs vidare studier, både på organismnivå och med ett storskaligt synsätt för att få en enhetlig bild över denna restaureringsåtgärd.
196

Bases para aplicação de índices biológicos no biomonitoramento de ambientes lóticos - comunidade bentônica / Bases for Biological Index use in lotic Environment Biomonitoring - Benthic Community

Watanabe, Helena Mitiko 18 September 2007 (has links)
A utilização da comunidade bentônica em biomonitoramento, como indicadora da qualidade de ambientes aquáticos, encontra-se atualmente bem estabelecida. Das duas abordagens sugeridas pelo Protocolo de Avaliação Rápida da USEPA, a que utiliza um único meso-hábitat mostra-se ideal para o biomonitoramento sendo, portanto, necessário estabelecer qual meso-hábitat utilizar. Este trabalho pretende avaliar a sensibilidade e adequabilidade de diferentes meso-hábitat ribeirinhos em biomonitoramento. Foram estabelecidos oito pontos de amostragem, localizados nos rios Atibainha, Cachoeira e Atibaia, na Bacia Hidrográfica do Rio Piracicaba, São Paulo. Amostras foram coletadas na estação chuvosa (março), para análise de variáveis ambientais (água e sedimento) e biótica (macroinvertebrados bentônicos). Os organismos da comunidade bentônica foram identificados ao nível de família para os principais taxa. Os dados ambientais e bióticos foram submetidos à análise de agrupamento e ordenação, e para o diagnóstico da qualidade do ambiente aquático, índices individualizados e abordagem multimétrica foram utilizados. Tanto as variáveis ambientais quanto a biótica separaram nitidamente regiões de alto (3ª e 4ª ordens) e baixo gradiente (5ª e 6ª ordens). Dos meso-hábitats analisados por meio da comunidade bentônica, apenas canal e margem deposicional mostraram-se promissores e destes, margem deposicional mostrou-se o mais adequado para biomonitoramento, tanto por discernir o gradiente de poluição existente quanto por possibilitar a avaliação integrada de variáveis bióticas, químicas e toxicológicas, o que minimizaria esforços com acréscimo de informações. / The use of benthic communities in biomonitoring, as indicator of aquatic environmental quality is currently well established. Considering the two approaches suggested by Rapid Assessment Protocol of US-EPA, the single mesohabitat approach is ideal for the practical purposes of biomonitoring, being hence necessary to establish which meso-habitat to use. This paper aims to evaluate the sensitivity and suitability of different river meso-habitats for biomonitoring. Eight sampling sites were established along Atibainha, Cachoeira and Atibaia Rivers, in Piracicaba River basin, São Paulo State, Brazil. Sampling were carried out in rainy season (March) to evaluate environmental (water and sediment) and biotic (benthic macroinvertebrates) parameters. The major benthic taxa were identified to family level.. Environmental and biotic data were submitted to cluster and ordination analysis, and for the quality of aquatic environment diagnosis, individualized index and multimetrics approach were used. Both environmental and biotic parameters distinctly discriminated upper (3rd and 4th orders) from lower (5th and 6th orders) gradient regions. Among the meso-habitats analyzed by mean of the benthic community, only channel and depositional bank were promising and of the two, deposicional bank proved to be the most adequate for biomonitoring, both for discerning pollution gradient and for enabling an integrated assessment of biotic, chemical and toxicological parameters, minimizing efforts and adding information
197

Estabelecimento de uma estação de monitoramento de longo prazo em habitat bentônico de substrato consolidado no litoral do Atlântico Sul: (Ecorregião Southeastern Brazil) / Long-term monitoring station establishment in consolidated substrate benthic habitat in the South Atlantic Coast (Southeastern Brazil Ecoregion)

Sandy, Bruno Lenhaverde 24 August 2017 (has links)
Projetos de monitoramento de longo prazo estão sendo desenvolvidos internacionalmente a fim de monitorar continuamente os impactos que as mudanças climáticas globais vêm gerando nas comunidades marinhas bentônicas, entretanto, no âmbito nacional, há uma carência desse tipo de estudo e dados para a costa brasileira. O objetivo do presente estudo foi a instalação de uma estação de monitoramento de longo prazo, bem como a caracterização da comunidade bentônica presente no médiolitoral do costão rochoso à direita da Enseada de Palmas, no Parque Estadual da Ilha Anchieta (Ubatuba, SP) seguindo as diretrizes do \"Protocolo de Médiolitoral para Monitoramento de Comunidades de Costão Rochoso\" da ReBentos (Rede de Monitoramento de Habitats Bentônicos Costeiros). As amostragens dependentes semestrais (n = 3) foram realizadas no período de um ano, compreendendo o inverno de 2014 e o verão de 2015, utilizando fotoquadrados de 10x10 cm na faixa superior e 25x25 cm nas faixas intermediária e inferior. A análise variância ANOVA two way para dados repetidos revelou variação sazonal na largura das faixas das unidades operacionais (UO) Tetraclita (39,1 cm) e Macroalgas (27 cm) e no recobrimento percentual médio (RPM) das UO Cianobactéria (12,6%) na faixa superior, T. stalactifera (16,6%), Espaço vazio (38,4%) e Algas Calcárias Articuladas (55,7%) na faixa intermediária. As análises multivariadas (Cluster, nMDS e PCA) revelaram alta similaridade para as faixas superior (80%) e inferior (85%) e baixa (65%) para a faixa intermediaria, indicando que as maiores diferenças entre verão e inverno foram encontradas nesta faixa. Como o médiolitoral apresenta UO bioindicadoras de monitoramento, como T. stalactifera, A. beauvoisii e Sargassum vulgare, e de variação sazonal, então eleva-se a importância da realização, integração e continuidade de projetos de monitoramento de longo prazo em costões rochosos a fim de gerar dados históricos ao longo do litoral brasileiro / The development of long-term monitoring projects around the world aims to monitor continuously the impacts that global environmental changes (GEC) have been causing in the benthic marine communities. However, nationally, there are few monitoring studies and data for the Brazilian coast. In this study, we aimed to install a long-term monitoring station and characterize the benthic community located in the intertidal zone of the rocky shore in the right of the Cove of Palmas at the Anchieta Island State Park (Ubatuba, São Paulo state). We intended to do that by following the guidelines of the \"Intertidal Protocol for the Monitoring of Rocky Shore Communities\" (Rocky Shores Working group, ReBentos). We studied the rocky shore for a year and collected the dependent samples every semester (n = 3), encompassing the winter of 2014 and the summer of 2015. We used photoquadrats in the intertidal zone (10x10 cm in the upper band and 25x25 cm in the intermediate and lower bands). Two-way analysis of variance (ANOVA) for repeated measures reveled seasonal variation in the bandwidth of Tetraclita (39,1 cm) and Macroalgae (27 cm) operational units (OU) and in the average percentage overlap for Cyanobacteria (12,6%) at upper band, T. stalactifera (16,6%), Empty space (38,4%) and Articulated Calcareous Algae (55,7%) at intermediate band. Multivariate analysis (Cluster, nMDS and PCA) revealed high similarity for upper (80%) and lower (85%) bands and low similarity for intermediate band (65%), suggesting major differences between summer and winter in the intermediate band. As the intertidal zone has monitoring bioindicators operational units, like T. stalactifera, A. beauvoisii and Sargassum vulgare, and seasonal variation, it is of great importance to implement, integrate and continue long-term monitoring projects in rocky shores in order to generate Brazilian coast historical data
198

Dinâmica do acoplamento bento-pelágico na plataforma interna ao largo de Ubatuba (São Paulo, Brasil) / Benthic-pelagic coupling dynamics on the inner shelf of Ubatuba (Sao Paulo, Brazil)

Alves, Betina Galerani Rodrigues 04 September 2009 (has links)
Os sedimentos costeiros são importantes globalmente, pois atuam como receptores de grandes quantidades de material orgânico alóctone e autóctone, sendo responsáveis por cerca de 90% do enterramento de carbono no oceano global. Dentro dos ecossistemas de plataforma continental, a fauna bêntica desempenha papel vital tanto como receptora de energia proveniente do pelagial, quanto como fornecedora de energia para os organismos demersais e de nutrientes para o fitoplâncton. O objetivo principal do presente trabalho foi investigar a variação temporal da dinâmica da macrofauna bêntica na plataforma interna de Ubatuba. A dinâmica bêntica foi analisada pela abundância, biomassa, descritores da comunidade (riqueza, diversidade, equitatividade) e análise trófica dos grupos mais abundantes, em função da origem e composição da matéria orgânica sedimentar. As coletas foram realizadas mensalmente em uma estação fixa, com início em outubro de 2006, por um período de um ano. A estação fixa possui uma profundidade de 40 m e um regime oceanográfico de transição entre águas costeiras e de plataforma continental. A composição da matéria orgânica em termos de MOT, fitopigmentos, fitodetritos e biomarcadores lipídicos apresentou uma complexidade típica de ambientes de plataforma interna, relacionados à dinâmica oceanográfica que rege os principais eventos de acúmulo ou remoção da matéria orgânica lábil na região de Ubatuba. A composição dos biomarcadores lipídicos presentes no sedimento evidenciou que a matéria orgânica particulada na região de plataforma interna de Ubatuba possui uma origem principalmente autóctone, e que está constituída por uma combinação de material derivado do plâncton vivo ou detrítico, da produção bacteriana e da fauna associada ao sedimento, havendo uma contribuição terrestre relativamente pequena. O presente estudo indicou que a dinâmica bêntica na região da plataforma interna de Ubatuba é moldada por forçantes ambientais, como a intrusão de massas dágua (e.g. ACAS) trazendo nutrientes para a zona fótica e estimulando a produção primária fitoplanctônica nova, induzindo o aumento na densidade e biomassa bêntica. A chegada de frentes frias, com ventos fortes, mistura da coluna dágua e revolvimento do fundo também possui fundamental importância, através do decréscimo nos valores dos parâmetros da comunidade bêntica. Esse padrão de acúmulo e remoção sugere que a biota bêntica da plataforma interna de Ubatuba esteja numa constante dinâmica de colonização e recolonização, que pode ser chave na manutenção de altos níveis de riqueza e equitatividade na região. Os resultados obtidos no presente estudo sugerem um íntimo e complexo acoplamento bentopelágico dependente, por um lado, de eventos oceanográficos de mesoescala (i.e. centenas de km; intrusão da ACAS) e, por outro, de eventos atmosféricos que influenciam o sistema bêntico em escala local, através da ressuspensão de sedimentos. / Coastal sediments are globally important for their role in the carbon cycle, being responsible for about 90% of the carbon burial in the global ocean. In continental shelf ecosystems, benthic communities play a vital role receiving energy from the pelagic system, serving as food source for demersal organisms, recycling nutrients back to the water column and sequestering part of the carbon into deeper layers of marine sediments. The present study aimed to investigate the variation on the dynamics of the benthic macrofauna on the inner shelf off Ubatuba-SP. Benthic macrofauna abundance, biomass, species richness, diversity, equitability and polychaete trophic groups were compared with the origin and composition of sedimentary organic matter. Sampling was carried out on a monthly basis starting in October 2006 for a year in a permanent station at 40 meters depth. The area is characterized by a transition between coastal and oceanic regimens. Sedimentary organic matter composition in terms of total organic matter, lipid biomarkers and phytopigments and phytodetritus showed a complexity typical from inner shelves and was driven by oceanic and atmospheric dynamics. Lipid biomarker composition revealed that particulated organic matter was mainly derived from autochthonous sources, composed of a combination of material derived from live plankton and detritic remains, bacterial production and from the benthic metazoan fauna. Terrestrial contribution to the sediment organic matter was small. The present study indicated that the benthic dynamics in the inner shelf off Ubatuba is molded by environmental forcing, especially the intrusion of water masses onto the shelf (e.g. ACAS), which brings nutrients to the euphotic zone stimulating new phytoplanktonic primary production. This enhances the flux of organic matter to the bottom increasing the benthic biota density and biomass. The arrival of cold fronts, with strong S-SW winds promoting water column mixing and sediment resuspension, was also fundamental in decreasing benthic community parameters (i.e. abundance and biomass). The dynamics of organic matter accumulation and removal suggest that the benthic biota in the inner shelf of Ubatuba is subjected to a constant pattern of settling and recolonization, which can be a key factor in the maintenance of high levels of species richness and equitability. The results obtained in the present study suggest a strong and complex benthic-pelagic coupling, influenced by mesoescale oceanographic events (i.e. hundreds of km; intrusion of ACAS) on the one hand and, on the other, by atmospheric events influencing the benthic system on a local scale, through the remobilization of sediments.
199

Padrões de estruturação de comunidades marinhas bentônicas de substrato consolidado do infralitoral - Praia de Fora à Ponta do Norte - Parque Estadual da Ilha Anchieta, Ubatuba, SP / Structural patterns of marine benthic hard Bottom communities of infralittoral - De Fora Beach to Do Norte End - Anchieta Island State Park - Ubatuba, SP

Ribeiro, Henrique Lauand 12 May 2010 (has links)
Os estudos de ecologia descritiva de comunidades marinhas bentônicas, tanto as de substratos consolidados (costões rochosos, recifes de corais, recifes de arenitos e bancos de algas calcárias) como as de substratos inconsolidados (areia, silte e sedimentos de baixa granulação), apontam para uma busca, ainda não finalizada, por padrões de distribuição que possam apresentar-se como modelo recorrente, sendo capazes de predizer sobre a composição de uma comunidade local. Como exemplos bem sucedidos, na busca de padrões, sendo marcos históricos no desenvolvimento da ecologia descritiva de comunidades marinhas bentônicas, temos as abordagens da zonação e de níveis de fundo, que buscaram encontrar um meio prático para descrições generalistas em larga escala que se apresentassem universais. No Brasil são caracterizados 3 momentos históricos sobre ecologia descritiva de comunidades marinhas bentônicas de substrato consolidado, que se caracterizam pelo uso de espécies como unidade operacional, recorrendo pouco a abordagens alternativas para ganho de conhecimento sobre grandes áreas. Neste estudo foi utilizado o método alternativo Caracterização fisionômica de comunidades marinhas de substrato consolidado para descrição dessas comunidades no infralitoral e busca por padrões de estruturação gerais visualmente evidentes. Este estudo foi realizado no Parque Estadual da Ilha Anchieta, Ubatuba SP, no infralitoral do costão oeste da Enseada das Palmas, compreendido entre as coordenadas 23°31\'44.37\"S / 045° 3\'38.07\"O e 23°32\'1.62\"S / 045° 3\'39.17\"O. Como principais resultados foram encontrados 24 povoamentos descritos na Abordagem 1, 20 povoamentos no inverno e 23 no verão . Na Abordagem 2, 19, povoamentos no inverno e, na Abordagem 3., 22 no verão. Os resultados quantitativos mostram, discriminados no costão estudado, a formação de 2 grupos gerais, que se mantiveram os mesmos no inverno e no verão, permitindo a conclusão de que há um padrão geral de estruturação da comunidade visualizada. Os povoamentos determinantes na divisão dos 2 grupos foram: Colônia de Palythoa, Tapete de Amphiroa e Jania, Banco de Dichotomaria e Região de Substrato Inconsolidado. Constata-se o mundo natural como um lugar desigual, que se manifesta em manchas ou remendos distintos, apresentando-se de muitas formas e com uma ampla gama de escalas. Os resultados foram vistos sob uma perspectiva exploratória, uma vez que se buscou encontrar padrões de distribuição das comunidades apenas a partir da unidade visual povoamento, sem o registro de dados de condições ambientais. Nessa busca, visualizando tal mosaico de distribuição de formas, cores, estrutura e composição em diferentes escalas encontramos padrões gerais de distribuição da comunidade, aqui representados por 2 grandes grupos, caracterizados por estarem em um nível acima de povoamentos ou supra povoamentos / The studies on descriptive ecology of marine benthic communities, hard bottom (Rocky Shores, Coral Reefs, Sandstone Rock Reefs and Rodolith Beds) as much as soft bottom communities (sand, silt and soft substrate of low granular material), lead to a non finished search for distribution patterns that may present it as a model able to predict about the local communities composition. As successful examples on searching for patterns as historical reference on the developing of descriptive ecology of marine benthic communities we have the zonation and bottom level approaches, that seek for a practical way to describe on a general and large scale universal patterns of distribution. In Brazil we found 3 historical moments about studies dealing with descriptive ecology of hard bottom marine benthic communities, which are characterized by the use of species as an operational unit, taking advantage of few alternative approaches to acquire knowledge about the communities in large areas. In this study the alternative methodology Physiognomic characterization of hard bottom marine benthic communities was applied, to describe such communities in infra-littoral regions and to search for general structural patterns visually evident. This study was made in Anchieta Island State Park, Ubatuba SP, Brazil, on the west rocky shore of Palmas Bay, located between the geographical positions 23°31\'44.37\"S / 045° 3\'38.07\"W and 23°32\'1.62\"S / 045° 3\'39.17\"W. As main results, 24 settlements described by the first approach were found; 20 settlements in winter season and 23 in summer season by the second approach ; 19 settlements in winter season e 22 in summer season by the third approach. The quantitative results show 2 general groups found on the studied rocky shore that were the same both in winter and summer seasons, allowing that we come to the conclusion that there is a general structural pattern visualized in the communities. The determinant settlements to the formation of the 2 groups were Palythoa Colony, Amphiroa and Jania Turf, Dichotomaria Bed and Soft Bottom Region. We face the fact that nature is an unequal place, which manifests this visual difference on patches of different sizes, showing many forms and colors on a huge range of scales. The results were reviewed under an exploratory perspective, searching first for structural patterns of these communities only from the visual unit called settlement, without the data of environmental conditions. On this search, visualizing the distribution of forms, colors, structure and composition mosaic on different scales we found general patterns of communities distribution that here are represented by 2 large groups, characterized by being on a higher level than the one of the settlement
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Escalas de variação de comunidades bentônicas de infralitoral em ilhas pertencentes a uma área de proteção ambiental no Sudeste do Brasil: reflexões sobre processos estruturadores e subsídios para monitoramento / Scales of variation of subtidal benthic communities in islands within a marine protected area in SE Brazil: clues about structuring processes and subsidies for monitoring

Silva, Gabriela Carvalho Lourenço da 25 June 2015 (has links)
Como os processos que definem distribuições de espécies operam em diferentes escalas espaciais, abordagens multi-escalares são necessárias para que a variabilidade do sistema seja considerada no desenvolvimento de desenhos amostrais. Estudos sobre padrões espaciais de distribuição são necessários para servir de base para monitoramento e avaliações de impactos. Este trabalho avaliou a variação espacial de comunidades de infralitoral, em costões rochosos de três ilhas na Estação Ecológica dos Tupinambás. Os padrões espaciais foram investigados em quatro escalas, que variam de poucos metros a dezenas de quilômetros. Foram amostradas as profundidades de 1 a 5 e de 5 a 10 metros, no verão e inverno de 2013 e verão de 2014. O recobrimento percentual das unidades biológicas foi extraído a partir de foto-quadrados de 50x50 cm, aleatorizados, seguindo um desenho amostral aninhado. Os dominantes foram analisados individualmente com análise de variância univariada. Algas Calcárias Articuladas (ACA) foram o grupo dominante em todas as ilhas, períodos e profundidades, além de influenciar padrões multivariados, evidenciados pelo PCA. O recobrimento médio de ACA variou de 36% a 89.56%, considerando toda a amostragem. Outros dominantes variaram de acordo com o período e profundidade de coleta, dentre eles, Sargassum sp., Codium intertextum e Asparagopsis taxiformis. Todas as análises multivariadas (PERMANOVA, Pairwise Comparisons e nMDS) revelaram alta variação entre ilhas. Todas as outras escalas apresentaram variabilidade significativa, exceto a de poucos metros. Estimativas de variação revelaram que a variação residual e a entre ilhas foram sempre maiores do que as das outras escalas, confirmando a heterogeneidade intrínseca em pequena escala e a complexidade de comunidades insulares. O monitoramento nesta UC deverá incorporar todas as escalas investigadas. / As processes that define species distributions operate at different spatial scales, multi-scale approaches are needed to account for the system\'s natural variability, when developing sampling designs. Research about spatial patterns is essential to generate data to drive monitoring initiatives and impact assessments. The present study evaluated the spatial variability of subtidal rocky shore communities in three islands within the Ecological Station of Tupinambás. Spatial patterns were investigated across four scales, ranging from few meters to tens of kilometers, from 1 to 5 and from 5 to 10 m depth, in the summer and winter of 2013 and summer of 2014. Percent cover of the biological units was evaluated from photo-quadrats of 50x50 cm, randomly scattered, following a nested design. Dominant species and morphological groups were analyzed individually by univariate analyses of variance. Articulated Calcareous Algae (ACA) were the dominant group in all islands, depths and periods, and the main driver of multivariate patterns, as evidenced by the PCA. Mean cover of ACA varied from 36% to 89.56%, considering all occasions. Other dominant species were the algae Sargassum sp., Codium intertextum and Asparagopsis taxiformis, which varied according to sampling period and depth. All multivariate procedures (PERMANOVA, Pairwise Comparisons and nMDS plots) showed the highest variability among islands. All the other scales, except of few meters, presented significant variability. Estimates of variation showed that residual and intra-island variability were always higher than in other scales, confirming the intrinsic small-scale patchiness of marine assemblages and the complexity of insular communities. Monitoring efforts in this MPA should incorporate all the examined scales.

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