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A three-year mark-recapture study in a remnant population of Crocodylus acutus Cuvier in Portete Bay (Guajira, Colombia) Gayana
Espinosa,Mara I; Bertin,Angéline; Gómez,John; Mejía,Florencio; Guerra,Martha; Baez,Lina; Gouin,Nicolas; Patiño,Edgar.
The American crocodile, Crocodylus acutus, has experienced important population declines worldwide due to human persecution, overexploitation and habitat loss. C. acutus remains critically endangered in some countries such as Colombia where the lack of detailed surveys on its ecology and distribution constitutes a major barrier to the development of effective conservation strategies. We conducted a three-year capture-recapture study to investigate the demographic status of C. acutus and to identify environmental variables likely to in uence its distribution in Portete Bay (Colombia). We estimated the crocodile population to be relatively small (< 140 animals), to include very few adults, and to demonstrate a very strong de cit in females in the juvenile...
Tipo: Journal article Palavras-chave: Capture-recapture; Crocodile; Environmental variables; Mangrove.
Ano: 2012 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382012000200006
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Diversity and fish distribution at Rodrigo de Freitas Lagoon, Rio de Janeiro State, Brazil, using GIS - doi: 10.4025/actascibiolsci.v36i1.18563 Biological Sciences
Moraes, Luzia Alice Ferreira de; Universidade Federal do Estado do Rio de Janeiro; Andreata, José Vanderli; Universidade Santa Úrsula; Oliveira, Bruno Teixeira de; Universidade Federal do Estado do Rio de Janeiro.
Fish fauna is considered a good indicator of water quality. The Rodrigo de Freitas Lagoon is located in Rio de Janeiro city with a great scenic beauty. However, along the years, the Lagoon has been negatively impacted by human activities which can be seen in massive fish deaths and blooms of toxic algae. This study evaluated fish abundance and diversity in two historical periods, and between areas of capture. Multivariate data analyses were performed to find similar groups of fish fauna and to evaluate fish abundance and their seasonal and spatial variation. It was also used the algebraic language as a tool to combine raster layers as dissolved oxygen in surface, bathymetry and fish abundance by using rules and conditions involved in the fish zoning. The...
Tipo: Info:eu-repo/semantics/article Palavras-chave: 2.05.00.00-9 ichtyofauna abundance; Environmental variables; Map algebra Ecologia de peixes.
Ano: 2013 URL: http://periodicos.uem.br/ojs/index.php/ActaSciBiolSci/article/view/18563
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Efeitos da ocupação do solo, do uso da água e da idade das albufeiras nos parâmetros ambientais e na estrutura das comunidades zooplanctónicas IPB - Escola Superior Agrária
Geraldes, Ana Maria.
O presente trabalho decorreu em três albufeiras de idades distintas e sujeitas a diferentes tipos de perturbações de origem antropogénica. Estes sistemas aquáticos localizam-se na parte portuguesa da Bacia Hidrográfica do Rio Douro, na região de Trás-os-Montes. A albufeira da Serra Serrada foi criada em 1995 com o objectivo de abastecer de água a cidade de Bragança, actualmente com 34.750 habitantes. Como consequência do intenso consumo de água ocorrem flutuações de grande amplitude no seu nível. Por outro lado, na bacia de drenagem desta albufeira a pastorícia é particularmente intensa durante o Verão. Devido a esta actividade ocorrem nesta área, fogos frequentes que são induzidos pelos pastores com o objectivo de obterem melhores pastagens. A albufeira...
Tipo: Book Palavras-chave: Albufeiras; Estado trófico; Uso do solo; Idade das albufeiras; Qualidade da água; Flutuações no nível da água; Variáveis ambientais; Comunidades fito e zooplactónicas; Precipitação; Macrófitos; Actividade da fosfatase alcalina; Regeneração do ortofosfato; Nutrientes; Reservoirs; Trophic state; Nutrients; Land use; Reservoir age; Water quality; Water level fluctuation; Environmental variables; Phytoplankton and zooplankton assemblages; Precipitation; Macrophytes; Kaline phosphatase activity; Orthophosphate regeneration.
Ano: 2004 URL: http://hdl.handle.net/10198/770
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Estrutura e dinâmica da comunidade fitoplanctônica e sua relação com as variáveis ambientais na lagoa Mãe-Bá, Estado do Espírito Santo, Brasil - DOI: 10.4025/actascibiolsci.v31i3.1266 Biological Sciences
Souza, Bruna D'Ângela de; UENF; Fernandes, Valéria Oliveira; UFES.
O presente estudo objetivou avaliar a estrutura e dinâmica da comunidade fitoplanctônica e sua relação com as variáveis ambientais na lagoa Mãe-Bá. Foram realizadas quatro amostragens com periodicidade quinzenal, abrangendo as estações seca e chuvosa, na região limnética de dois pontos de amostragem submetidos a diferentes condições ambientais. O fitoplâncton foi analisado quanto à riqueza, densidade total, abundância, dominância, diversidade e equitabilidade. Foram determinados: temperatura (ar/água), transparência, zona eufótica, profundidade, pH, oxigênio dissolvido, turbidez, condutividade elétrica, sólidos totais dissolvidos e suspensos, concentrações de nutrientes. Foram registrados 138 táxons, sendo a Classe Cyanophyceae mais representativa em...
Palavras-chave: 2.00.00.00-6 Ciências Biológicas fitoplâncton; Lagoa costeira; Variáveis ambientais Botânica phytoplankton; Coastal lagoon; Environmental variables.
Ano: 2009 URL: http://periodicos.uem.br/ojs/index.php/ActaSciBiolSci/article/view/1266
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Identificación de áreas degradadas, por erosión en cárcavas, en el eje neovolcánico mexicano. Colegio de Postgraduados
Zamora Tirado, Paula Erika.
El presente el trabajo se desarrolló en la provincia fisiográfica Eje Volcánico Mexicano donde los procesos de erosión por cárcavas son frecuentes y relevantes, ocasionado importantes pérdidas económicas y ambientales, con el objetivo de caracterizar los parámetros ambientales que influyen en la formación de cárcavas, como: material parental, suelo, fase física, erosionabilidad, pendiente, longitud de pendiente, orientación, curvatura horizontal y vertical, índice de posición topográfica, índice topográfico de humedad, índice de Fournier, índice de vegetación ajustada al suelo y distancia a estructuras volcánicas. Se realizó un Análisis de Componentes Principales (ACP) con el propósito de identificar las variables que mejor expliquen la formación de...
Palavras-chave: Análisis de componentes principales; Análisis de máxima verosimilitud; Erosión en cárcavas; Modelación en cárcavas; Variables ambientales; Principal component analysis; Maximum likelihood analysis; Gully; Ravine modeling; Environmental variables; Edafología; Maestría.
Ano: 2014 URL: http://hdl.handle.net/10521/2372
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Influence of environmental variables on planktonic and phytobenthic communities in earthen ponds at Makoba, Zanzibar OceanDocs
Kyewalyanga, M.S.; Mwandya, A.W..
A study was conducted between July 2002 and June 2003 to assess the role of salinity, temperature, pH and dissolved oxygen on the abundance of planktonic (phyto- and zooplankton) and phytobenthic (algal mats) communities in shallow (40 cm depth) earthen ponds at Makoba, Zanzibar. Among the zooplankton, rotifer abundance peaked during the rainy period (salinity of 27–42‰) while protozoa and copepods were most abundant during the dry period (max salinity of 70‰). However, no season effects were seen on the phytobenthos. The most abundant genera were Pseudonitzschia sp., Schizothrix sp., Microcoleus sp. and Oscillatoria sp. and in general, algal mats were available throughout the year. Other variables such as temperature, pH and oxygen concentration did not...
Tipo: Journal Contribution Palavras-chave: Pseudonitzschia; Schizothrix; Microcoleus; Oscillatoria; Environmental variables; Planktonic organisms Environmental conditions Salinity Temperature Fish ponds Algal mats Environmental conditions Salinity Temperature http://aims.fao.org/aos/agrovoc/c_32980 http://aims.fao.org/aos/agrovoc/c_6751 http://aims.fao.org/aos/agrovoc/c_7657.
Ano: 2004 URL: http://hdl.handle.net/1834/1109
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Modèles loglinéaires pour l'étude des associations entre captures par unité d'effort et variables hydroclimatiques ArchiMer
Badia, Jacques; Prouzet, Patrick.
In this paper we study associations between categorical variables. We present an approach based on loglinear modelling. A better knowledge of the influence of the intensity of tidal coefficient (cm) and of the rate of river flow (df) on catch per unit effort (cpue) of allis shad (Alosa alosa) was obtained. Analysis performed indicated that an increase of catch per unit effort is proportionally associated with the increase in the tidal coefficient. We also noted the influence of the rate of flow.
Tipo: Text Palavras-chave: Modèle loglinéaire; Capture par unité d'effort; Variables environnementales; Alosa alosa; Grande alose ou alose vraie; Loglinear model; Catch per unit effort; Environmental variables; Alosa alosa; Allis shad.
Ano: 1996 URL: http://archimer.ifremer.fr/doc/00188/29889/28338.pdf
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Revealing the Organization of Complex Adaptive Systems through Multivariate Time Series Modeling Ecology and Society
Angeler, David G; Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment; david.angeler@slu.se; Drakare, Stina; Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment ; stina.drakare@slu.se; Johnson, Richard K; Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment ; richard.johnson@slu.se.
Revealing the adaptive responses of ecological, social, and economic systems to a transforming biosphere is crucial for understanding system resilience and preventing collapse. However, testing the theory that underpins complex adaptive system organization (e.g., panarchy theory) is challenging. We used multivariate time series modeling to identify scale-specific system organization and, by extension, apparent resilience mechanisms. We used a 20-year time series of invertebrates and phytoplankton from 26 Swedish lakes to test the proposition that a few key-structuring environmental variables at specific scales create discontinuities in community dynamics. Cross-scale structure was manifested in two independent species groups within both communities across...
Tipo: Peer-Reviewed Reports Palavras-chave: Complex adaptive systems dynamics; Complex adaptive systems organization; Cross-scale structure; Discontinuities; Environmental variables; Invertebrates; Lakes; Panarchy; Phytoplankton; Resilience; Time series modeling.
Ano: 2011
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Temporal changes in fish species composition of headwater streams of the upper Paraguay and Paraná basins, Brazil - doi: 10.4025/actascibiolsci.v32i3.6160 Biological Sciences
Tondato, Karina Keyla; UFMT; Súarez, Yzel Rondon; Universidade Estadual de Mato Grosso do Sul, CInAM/Laboratório de Ecologia. Rod. Dourados-Itahum km 12. CEP 79804-970. Dourados-MS, Brasil.
This study was carried out in headwater streams in the Paraguay and Paraná river basins, with bi-monthly samples from January to November 2004, aiming to quantify the influence of environmental factors on the temporal rate of turnover in species composition of the fish communities. The environmental variables explained 73.5% of the variation in beta diversity and 52.5% of the variation in mean dissimilarity. Altitude was the only environmental descriptor that significantly explained the variation in beta diversity and mean dissimilarity in both basins.
Palavras-chave: Ecologia; Comunidades; Peixes; Riachos community ecology; Neotropical streams; Environmental variables Ecologia community ecology; Neotropical streams; Environmental variables.
Ano: 2010 URL: http://periodicos.uem.br/ojs/index.php/ActaSciBiolSci/article/view/6160
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Water level influences on body condition of Geophagus brasiliensis (Perciformes: Cichlidae) in a Brazilian oligotrophic reservoir Neotropical Ichthyology
Santos,Alejandra Filippo Gonzalez Neves dos; Santos,Luciano Neves dos; Araújo,Francisco Gerson.
Effects of water level fluctuations on body condition of Geophagus brasiliensis were studied in a 30 km² Brazilian oligotrophic reservoir. Physiological condition (K) and gonadosomatic index (GSI) were compared according to water level (low and high). Females' best conditions were associated to higher resources availability during high water, since gonad development did not change between low and high water. Males' condition did not change between water levels, while the highest gonad development occurred in low water. Females presented higher reproductive investment than males, which allocated most of energy for somatic development. This strategy could be a mechanism to undergo the stress caused by oligotrophic characteristics of the reservoir enhanced...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Environmental variables; Condition factor; Gonadosomatic index; Mass-length relationship; Impoundment.
Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252004000300007
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