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Spatial and Temporal Variation of Archaeal, Bacterial and Fungal Communities in Agricultural Soils

Pereira e Silva, Michele C.; Franco Dias, Armando Cavalcante; van Elsas, Jan Dirk; Salles, Joana Falcao
Fonte: PUBLIC LIBRARY SCIENCE; SAN FRANCISCO Publicador: PUBLIC LIBRARY SCIENCE; SAN FRANCISCO
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.27%
Background: Soil microbial communities are in constant change at many different temporal and spatial scales. However, the importance of these changes to the turnover of the soil microbial communities has been rarely studied simultaneously in space and time. Methodology/Principal Findings: In this study, we explored the temporal and spatial responses of soil bacterial, archaeal and fungal beta-diversities to abiotic parameters. Taking into account data from a 3-year sampling period, we analyzed the abundances and community structures of Archaea, Bacteria and Fungi along with key soil chemical parameters. We questioned how these abiotic variables influence the turnover of bacterial, archaeal and fungal communities and how they impact the long-term patterns of changes of the aforementioned soil communities. Interestingly, we found that the bacterial and fungal b-diversities are quite stable over time, whereas archaeal diversity showed significantly higher fluctuations. These fluctuations were reflected in temporal turnover caused by soil management through addition of N-fertilizers. Conclusions: Our study showed that management practices applied to agricultural soils might not significantly affect the bacterial and fungal communities...

Análise dos padrões espaciais de árvores em quatro formações florestais do estado de São Paulo, através de análisses de segunda ordem, como a função K de Ripley.; Spatial pattern analysis of trees of four forest communities in southeastern Brazil, using Ripley’s K function.

Capretz, Robson Louiz
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 17/12/2004 PT
Relevância na Pesquisa
36.34%
O padrão espacial das árvores em uma floresta é influenciado por variáveis abióticas e bióticas. Entre as principais variáveis abióticas estão o relevo, a disponibilidade de luz, nutrientes e água, e a caracterização do solo. Entre as principais variáveis bióticas estão os processos dependentes da densidade, tais como a competição intraespecífica e interespecífica, a herbivoria, a ocorrência de doenças, a fenologia e dispersão de sementes. Desse modo, investigar o padrão espacial das árvores, segundo suas classes de tamanho, e segundo suas espécies mais abundantes, pode fornecer evidências sobre a estrutura da comunidade vegetal. A descrição do padrão espacial das árvores e das espécies mais abundantes em diferentes formações florestais foi realizada usando ferramentas estatésticas mais apropriadas para investigar mapas das árvores. A Função K de Ripley tem como principais vantagens a possibilidade de detectar o padrão espacial em diversas escalas de distâncias simultaneamente, e avaliar a dependência espacial entre grupos de árvores. Os padrões observados foram comparados com os modelos de Completa Aleatoriedade Espacial, para a função univariada, e de Completa Independência Espacial...

Reviving käthe seidel’s legacy to University of Minho

Mina, Isabel Aguiar Pinto; Ferreira, M. J.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em 23/09/2006 ENG
Relevância na Pesquisa
36.14%
Site da conferência internacional: http://www.wetconf10.adp.pt/home_p.htm; In the 80’s Prof. Käthe Seidel was in Portugal by invitation of the University of Minho (UM). The relationship established led to the donation of Seidel’s laboratory to UM, to create a Limnological Laboratory. Some institutional and personal reasons rendered this unviable and until now, Seidel’s legacy at UM is resumed to some German bibliography, equipment and unpublished work. Prof. Kickuth was Seidels’ disciple. His technology is based on a rooted emergent macrophyte system of horizontal subsurface flow that relied on optimized substrate planted with Phragmites. Aiming to determine the efficiency of Kickuth’s process and to understand the role of the biotic communities presented on these optimized substrates, mensal sampling campaigns were made in a Constructed Wetland (CW) located in the North of Portugal. The sampling campaigns began on January 2005. Inlet (IN) and outlet (OUT) wastewater simple samples and substrate samples were taken from one of the two CW’s beds. In situ determinations of temperature, pH and redox potential were recorded, and IN and OUT wastewater samples were analysed for BOD5, COD and TSS; estimated densities of some microbiological communities were assessed by the recovery of colony formed units (CFU/ml) on solid culture media...

Short-term versus long-term changes in the benthic communities of a small coastal lagoon: implications for ecological status assessment

Félix, PM; Chainho, P; Costa, Jl; Correia, MJ; Chaves, ML; Medeiros, JP; Cabral, HN; Wouters, N; Bernardo, J; Costa, AM; Cristo, M; Silva, G; Azeda, C; Tavares, P; Costa, MJ; Cancela Da Fonseca, L
Fonte: Vie et Milieu Observatoire Océanologique - Laboratoire Arago - Université Pierre et Marie Curie 66650 Banyuls-sur-Mer - France Fax: (33) (0)4 68 88 16 99 Email: vimilieu@obs-banyuls.fr Publicador: Vie et Milieu Observatoire Océanologique - Laboratoire Arago - Université Pierre et Marie Curie 66650 Banyuls-sur-Mer - France Fax: (33) (0)4 68 88 16 99 Email: vimilieu@obs-banyuls.fr
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
36.14%
The characteristic high variability and low predictability of coastal lagoons, due to strong changes in marine and freshwater inputs, make these ecosystems an interesting casestudy. The small Melides landlocked coastal lagoon in SW Portugal is a paradigmatic example, with a biological community highly stressed by these phenomena. Benthic macroinvertebrate samples were collected in 1998/99 and 2009 and each year, in different seasons and addressing different environmental conditions influenced by the connection to the sea and rainfall regime. Major spatial and temporal patterns in benthic communities were investigated using some invertebrate attributes (e.g. community composition, density, species richness and diversity). A very low taxonomic species richness and diversity was found in the Melides lagoon and only a much reduced number of species occurred along all sampling periods and in both sampling campaigns. Although the colonization events play a crucial role, the persistence of the observed species was mainly associated to abiotic factors, such as salinity, temperature and dissolved oxygen. Despite the potential reduction in anthropogenic pressure, by the construction of a sewage treatment plant and a reduction of urban occupation...

Integrity of fluvial fish communities is subject to environmental gradients in mountain streams, Sierra de Aroa, north Caribbean coast, Venezuela

Rodríguez-Olarte,Douglas; Amaro,Ahyran; Coronel,Jorge; Taphorn B.,Donald C.
Fonte: Sociedade Brasileira de Ictiologia Publicador: Sociedade Brasileira de Ictiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2006 EN
Relevância na Pesquisa
36.34%
We examined physical habitat and fish assemblages in rivers of the Aroa Mountains (Venezuela) with different levels of environmental protection due to the creation of Yurubí National Park within the drainage. We developed an Index of Biotic Integrity (IBI) and evaluated it using principal components analysis (PCA) and canonical correspondence analysis (CCA). Tributary rivers were divided into classes according to their origin (protected by the park) and physical characteristics of each, including substrate. Fishes were captured using standardized electrofishing. Fish communities showed greater species richness in heterogeneous habitat and protected rivers but overall abundance was higher in unprotected and impacted rivers. The IBI was sensitive to these differences and the scores were higher in protected rivers. The IBI detected degree of disturbance of fish communities without direct consideration of habitat parameters measured. The PCA revealed a gradient in substrate heterogeneity. Similarly, CCA revealed differences in fish assemblage composition along the environmental gradient and that varied with protection status of the river. The relationship between PCA and IBI scores was highly significant (r² = 0.61, P < 0.0001). The PCA and CCA analysis moderately validated the structure and predictability of IBI; but it is still necessary to refine the model and to extend its application for more time and over a wider area.

At Limits of Life: Multidisciplinary Insights Reveal Environmental Constraints on Biotic Diversity in Continental Antarctica

Magalhães, Catarina; Stevens, Mark I.; Cary, S. Craig; Ball, Becky A.; Storey, Bryan C.; Wall, Diana H.; Türk, Roman; Ruprecht, Ulrike
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 19/09/2012 EN
Relevância na Pesquisa
36.42%
Multitrophic communities that maintain the functionality of the extreme Antarctic terrestrial ecosystems, while the simplest of any natural community, are still challenging our knowledge about the limits to life on earth. In this study, we describe and interpret the linkage between the diversity of different trophic level communities to the geological morphology and soil geochemistry in the remote Transantarctic Mountains (Darwin Mountains, 80°S). We examined the distribution and diversity of biota (bacteria, cyanobacteria, lichens, algae, invertebrates) with respect to elevation, age of glacial drift sheets, and soil physicochemistry. Results showed an abiotic spatial gradient with respect to the diversity of the organisms across different trophic levels. More complex communities, in terms of trophic level diversity, were related to the weakly developed younger drifts (Hatherton and Britannia) with higher soil C/N ratio and lower total soluble salts content (thus lower conductivity). Our results indicate that an increase of ion concentration from younger to older drift regions drives a succession of complex to more simple communities, in terms of number of trophic levels and diversity within each group of organisms analysed. This study revealed that integrating diversity across multi-trophic levels of biotic communities with abiotic spatial heterogeneity and geological history is fundamental to understand environmental constraints influencing biological distribution in Antarctic soil ecosystems.

Multi-Scale, Direct and Indirect Effects of the Urban Stream Syndrome on Amphibian Communities in Streams

Canessa, Stefano; Parris, Kirsten M.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 29/07/2013 EN
Relevância na Pesquisa
36.19%
Urbanization affects streams by modifying hydrology, increasing pollution and disrupting in-stream and riparian conditions, leading to negative responses by biotic communities. Given the global trend of increasing urbanization, improved understanding of its direct and indirect effects at multiple scales is needed to assist management. The theory of stream ecology suggests that the riverscape and the surrounding landscape are inextricably linked, and watershed-scale processes will also affect in-stream conditions and communities. This is particularly true for species with semi-aquatic life cycles, such as amphibians, which transfer energy between streams and surrounding terrestrial areas. We related measures of urbanization at different scales to frog communities in streams along an urbanization gradient in Melbourne, Australia. We used boosted regression trees to determine the importance of predictors and the shape of species responses. We then used structural equation models to investigate possible indirect effects of watershed imperviousness on in-stream parameters. The proportion of riparian vegetation and road density surrounding the site at the reach scale (500-m radius) had positive and negative effects, respectively, on species richness and on the occurrence of the two most common species in the area (Criniasignifera and Limnodynastesdumerilii). Road density and local aquatic vegetation interacted in influencing species richness...

Effect of Mining Activities in Biotic Communities of Villa de la Paz, San Luis Potosi, Mexico

Espinosa-Reyes, Guillermo; González-Mille, Donaji J.; Ilizaliturri-Hernández, César A.; Mejía-Saavedra, Jesús; Cilia-López, V. Gabriela; Costilla-Salazar, Rogelio; Díaz-Barriga, Fernando
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.56%
Mining is one of the most important industrial activities worldwide. During its different stages numerous impacts are generated to the environment. The activities in the region have generated a great amount of mining residues, which have caused severe pollution and health effects in both human population and biotic components. The aim of this paper was to assess the impact of mining activities on biotic communities within the district of Villa de la Paz. The results showed that the concentrations of As and Pb in soil were higher than the national regulations for urban or agricultural areas. The bioavailability of these metals was certified by the presence of them in the roots of species of plants and in kidneys and livers of wild rodents. In regard to the community analysis, the sites that were located close to the mining district of Villa de la Paz registered a lower biological diversity, in both plants and wild rodents, aside from showing a change in the species composition of plant communities. The results of this study are evidence of the impact of mining on biotic communities, and the need to take into account the wildlife in the assessment of contaminated sites.

Ecosystem development in roadside grasslands: biotic control, plant–soil interactions and dispersal limitations

García-Palacios, Pablo; Bowker, Matthew A.; Maestre, Fernando T.; Soliveres, Santiago; Valladares, Fernando; Papadopoulos, Jorge; Escudero, Adrián
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/2011 EN
Relevância na Pesquisa
36.37%
Roadside grasslands undergoing secondary succession are abundant, and represent ecologically meaningful examples of novel, human-created ecosystems. Interactions between plant and soil communities (hereafter plant–soil interactions) are of major importance in understanding the role of biotic control in ecosystem functioning, but little is known about these links in the context of ecosystem restoration and succession. The assessment of the key biotic communities and interactions driving ecosystem development will help practitioners to better allocate the limited resources devoted to roadside grassland restoration. We surveyed roadside grasslands from three successional stages (0–2, 7–9 and > 20 years) in two Mediterranean regions of Spain. Structural equation modeling was used to evaluate how interactions between plants, biological soil crusts [BSCs], and soil microbial functional diversity [soil microorganisms] affect indicators of ecosystem development and restoration: plant similarity to the reference ecosystem, erosion control and soil C storage and N accumulation. Changes in plant community composition along the successional gradient exerted the strongest influence on these indicators. High BSC cover was associated with high soil stability...

Spatial scale and abundance patterns of large fish communities in freshwater marshes of the Florida Everglades

Chick, John H.; Ruetz, Carl R.; Trexler, Joel C.
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.19%
Anthropogenic habitat alterations and water-management practices have imposed an artificial spatial scale onto the once contiguous freshwater marshes of the Florida Everglades. To gain insight into how these changes may affect biotic communities, we examined whether variation in the abundance and community structure of large fishes (SL . 8 cm) in Everglades marshes varied more at regional or intraregional scales, and whether this variation was related to hydroperiod, water depth, floating mat volume, and vegetation density. From October 1997 to October 2002, we used an airboat electrofisher to sample large fishes at sites within three regions of the Everglades. Each of these regions is subject to unique watermanagement schedules. Dry-down events (water depth , 10 cm) occurred at several sites during spring in 1999, 2000, 2001, and 2002. The 2001 dry-down event was the most severe and widespread. Abundance of several fishes decreased significantly through time, and the number of days post-dry-down covaried significantly with abundance for several species. Processes operating at the regional scale appear to play important roles in regulating large fishes. The most pronounced patterns in abundance and community structure occurred at the regional scale...

At limits of life: multidisciplinary insights reveal environmental constraints on biotic diversity in continental Antarctica

Magalhaes, C.; Stevens, M.; Cary, C.; Ball, B.; Storey, B.; Wall, D.; Turk, R.; Ruprecht, U.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
36.42%
Multitrophic communities that maintain the functionality of the extreme Antarctic terrestrial ecosystems, while the simplest of any natural community, are still challenging our knowledge about the limits to life on earth. In this study, we describe and interpret the linkage between the diversity of different trophic level communities to the geological morphology and soil geochemistry in the remote Transantarctic Mountains (Darwin Mountains, 80uS). We examined the distribution and diversity of biota (bacteria, cyanobacteria, lichens, algae, invertebrates) with respect to elevation, age of glacial drift sheets, and soil physicochemistry. Results showed an abiotic spatial gradient with respect to the diversity of the organisms across different trophic levels. More complex communities, in terms of trophic level diversity, were related to the weakly developed younger drifts (Hatherton and Britannia) with higher soil C/N ratio and lower total soluble salts content (thus lower conductivity). Our results indicate that an increase of ion concentration from younger to older drift regions drives a succession of complex to more simple communities, in terms of number of trophic levels and diversity within each group of organisms analysed. This study revealed that integrating diversity across multi-trophic levels of biotic communities with abiotic spatial heterogeneity and geological history is fundamental to understand environmental constraints influencing biological distribution in Antarctic soil ecosystems.; Catarina Magalhães...

Mediation of global change by local biotic and abiotic interactions.

Falkenberg, Laura J.
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2013
Relevância na Pesquisa
26.6%
Variation in environmental conditions is a pervasive feature of natural systems that has profound consequences for the structure of ecological communities. As a result of altered local conditions produced by human urbanisation, shifts in marine habitats from kelp forests to mats of turfing algae are increasingly common. Forecasting whether such ecological change will be accelerated or reversed as a function of modified global conditions is a new form of ecological enquiry. Throughout this thesis, I assessed the conceptual model that while cross-scale abiotic stressors can combine to have interactive effects, management of local conditions can counter-balance this change. My experimental manipulations were intended to test the hypotheses that; 1) cross-scale factors (i.e. local and global) will have interactive effects that increase the probability of expansion of turfs but not kelp, and, 2) management of local conditions (e.g. presence of biota, nutrient enrichment) will dampen the effects of global change on turfs (e.g. forecasted CO₂). Change in ecological communities is anticipated where altered environmental conditions have contrasting effects on interacting taxa that determine their composition and relative abundances. Experimental enrichment of CO₂ and nutrients influenced biomass accumulation of turf and kelp differently...

Investigating the role of biotic interactions in determining the degree of local adaptation and thus the potential response of plants to climate change; Untersuchung der Rolle biotischer Interaktionen für den Grad der lokalen Anpassung bei Pflanzen und der daraus folgenden potentiellen Reaktion von Pflanzen auf den Klimawandel

Tomiolo, Sara
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
EN
Relevância na Pesquisa
36.59%
Efficiently predicting the response of plant species to climate is one priority issue of present research, especially for Eastern Mediterranean systems, which according to predictions will be subject to increasing aridity. Current predictions on future species response to the expected change though are based on abiotic factors and virtually neglect the role of biotic interactions. The present thesis investigated the combined effect of climate, soil abiotic properties and biotic interactions on plant populations and community performance and potentially on their response to climate change. Firstly, the performance of plant species was investigated in the field performing a reciprocal seed sowing and soil transplant experiment combined with neighbour treatments between two sites along an aridity gradient. Four species were chosen in order to investigate species-specific effects. Secondly, a similar experiment was performed under controlled conditions with an additional soil treatment to tease apart the effects of soil abiotic properties and soil biota on plants. Thirdly, the change in species composition and richness of the communities emerging from transplanted soils under different climatic conditions were investigated in order to predict potential directions of community shifts under changed climate. The study was based on an integrated approach in which two types of biotic interactions that have been so far addressed separately were combined and analyzed jointly. By focusing on different spatial scales we were able to single out the driving factors and the main forces at play at the level of species and communities. Furthermore...

Biotic and abiotic effects on species interactions in a water stressed ecosystem: the effect of precipitation and grazing on the survival and establishment of the Mediterranean dwarf shrub Sarcopoterium spinosum; Effekte biotischer und abiotischer Faktoren auf die Interaktion zwischen Pflanzenarten in einem wassergestressten Ökosystem: Der Effekt von Beweidung und Niederschlag auf die Entwicklung und das Wachstum von Sarcopoterium spinosum

Rysavy, Anne
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
EN
Relevância na Pesquisa
26.67%
The question of how biotic and abiotic factors interact in determining the structure and function of plant communities has been a central focus in ecological research. Global change such as climate change or land-use changes may shift the balance of importance between abiotic and biotic factors, and thus alter the natural productivity and species composition of plant communities. This may particularly apply to regions already experiencing extreme conditions, e.g. drylands. Drylands, such as the Eastern Mediterranean have been predicted to be severely affected by climate change. In particular, climate scenarios suggest that water availability will decrease substantially due to decreasing precipitation combined with increasing temperatures, and that extreme weather events will become more frequent. However, abiotic factors not only regulate plants directly through their effect on demographic processes, but also indirectly through alterations in the biotic environment of the entire community. This indicates that under climate change, not only the abiotic but also the biotic environment will change, requiring adaptation, plastic response or escape from altered conditions. Unfortunately, the majority of studies predicting the response of single species or whole plant communities have largely overlooked biotic interactions...

Environmental conditions and biotic communities in Foz de Almargem and Salgados coastal lagoons, Algarve (South Portugal)

Coelho, Susana Isabel Eusébio
Fonte: Universidade do Algarve Publicador: Universidade do Algarve
Tipo: Tese de Doutorado
Publicado em //2013 ENG
Relevância na Pesquisa
46.57%
The present study intended to compare environmental conditions and biotic communities of two choked coastal lagoons located in the Algarve region, Foz de Almargem and Salgados, with the purpose of evaluating the effects of organic pollution from wastewater discharges in water quality and biotic communities from different levels of the food chain, namely phytoplankton and benthic macroinvertebrates. Both lagoons were seasonally connected to the sea, but most of the year they were isolated receiving the freshwater input from small rivers and wastewater (in Salgados). Data were collected from June 2001 to July 2002 in three sampling stations, according to a gradient of proximity with the sea. Characterization of environmental conditions was performed based on the study of hydrological parameters, physical and chemical water parameters, and sediment parameters. Phytoplankton communities were analyzed in terms of phytopigments concentrations; taxa composition, richness, abundance, diversity and salinity tolerance. Relations between phytoplankton and water parameters were analyzed through bivariate and multivariate statistical techniques. Results indicated that the two lagoons presented different phytoplankton communities, which were associated to water parameters and particularly with organic pollution in the case of Salgados lagoon. Taxonomic composition...

Review and evaluation of estuarine biotic indices to assess benthic condition

Pinto, Rute; Patrício, Joana; Baeta, Alexandra; Fath, Brian D.; Neto, João M.; Marques, João Carlos
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
ENG
Relevância na Pesquisa
36.29%
Recently there has been a growing interest and need for sound and robust ecological indices to evaluate ecosystem status and condition, mainly under the scope of the Water Framework Directive implementation. Although the conceptual basis for each index may rely on different assumptions and parameters, they share a common goal: to provide a useful tool that can be used in assessing the system's health and that could be applied in decision making. This paper focuses mainly on benthic community-based, biotic indices. We supply a general overview of several indices premises and assumptions as well as their main advantages and disadvantages. Furthermore, an illustrative example is provided of a straightforward application of benthic index of biotic integrity and benthic condition index. As a reference, their performance is compared to the Portuguese-benthic assessment tool. Limitations of the tested indices are discussed in context of the Mondego estuary (Portugal) case study.; http://www.sciencedirect.com/science/article/B6W87-4S38C07-1/1/8a495b1458d35c6ecf614eab10816ca3

A generalized neutral theory explains static and dynamic properties of biotic communities

Kalyuzhny, Michael; Kadmon, Ronen; Shnerb, Nadav M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 11/06/2014
Relevância na Pesquisa
36.19%
Understanding the forces shaping ecological communities is crucially important to basic science and conservation. In recent years, considerable progress was made in explaining communities using simple and general models, with neutral theory as a prominent example. However, while successful in explaining static patterns such as species abundance distributions, the neutral theory was criticized for making unrealistic predictions of fundamental dynamic patterns. Here we incorporate environmental stochasticity into the neutral framework, and show that the resulting generalized neutral theory is capable of predicting realistic patterns of both population and community dynamics. Applying the theory to real data (the tropical forest of Barro-Colorado Island), we find that it better fits the observed distribution of short-term fluctuations, the temporal scaling of such fluctuations, and the decay of compositional similarity with time, than the original theory, while retaining its power to explain static patterns of species abundance. Importantly, although the proposed theory is neutral (all species are functionally equivalent) and stochastic, it is a niche-based theory in the sense that species differ in their demographic responses to environmental variation. Our results show that this integration of niche forces and stochasticity within a minimalistic neutral framework is highly successful in explaining fundamental static and dynamic characteristics of ecological communities.

Spatial variablility of bee communities: from local assemblages to interaciton networks

Torné Noguera, Anna
Fonte: [Barcelona] : Universitat Autònoma de Barcelona, Publicador: [Barcelona] : Universitat Autònoma de Barcelona,
Tipo: Tesis i dissertacions electròniques; info:eu-repo/semantics/doctoralThesis; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2015 ENG
Relevância na Pesquisa
36.27%
Els organismes es troben distribuïts heterogèniament seguint patrons espacials, els quals són conseqüència de varis factors biòtics i abiòtics. Un dels principals objectius de l'ecologia és entendre com les interaccions de les espècies amb altres organismes i amb l'ambient determinen els seus patrons de distribució. En aquesta tesi analitzem els factors que expliquen la variabilitat espaial de les comunitats d'abelles i de les xarxes d'interaccions associades a escala local. L'estudi s'ha dut a terme al Parc del Garraf, en una àrea de 32km2 amb una vegetació arbustiva mediterrània homogènia, sense barreres ecològiques ni gradients marcats. Atès que les abelles depenen dels recursos florals i de nidificació per tal de sobreviure i reproduir-se, s'espera que aquests influenciïn la variabilitat espacial local de la comunitat d'abelles. En el primer capítol explorem com la distribució espacial dels recursos florals i de nidificació determina la variabilitat espaial local de la comunitat d'abelles. Hem trobat un patró geogràfic clar de variabilitat espaial en la composició de la comunitat d'abelles. Aquest patró es deu parcialment als recursos florals, amb una contribució de la disponibilitat de substrats de nidificació quasi insignificant...

Comparação entre o índice de integridade biótica e um método de multicritério, para análise da qualidade ambiental de três riachos tributários ao reservatório de Itaipu; Comparison between the index of biotic integrity and a method of multicriteria for analysis of the environmental quality of three streams tributaries to the of Itaipu reservoir; Comparison between the index of biotic integrity and a method of multicriteria for analysis of the environmental quality of three streams tributaries to the of Itaipu reservoir

Fernandes, Cleodimar; UFPR; Volpi, Neida Maria Patias; UFPR; Baumgartner, Gilmar; UNIOESTE
Fonte: Universidade Federal Fluminense - LATEC Publicador: Universidade Federal Fluminense - LATEC
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; Formato: application/pdf
Publicado em 27/05/2009 POR
Relevância na Pesquisa
36.59%
As atividades humanas têm exercido profunda e, normalmente, negativa influência sobre oscorpos hídricos, sendo que alguns efeitos negativos são devidos aos poluentes, enquantooutros estão associados às mudanças na hidrologia da bacia, modificações no habitat ealterações das fontes de energia. Muitas situações na tomada de decisão, sobre umambiente, envolvem a seleção de alternativas, eventos ou cursos de ações. No entanto,essas decisões geralmente possuem pontos de vista conflitantes, com diferentes juízos devalores, forçando os tomadores de decisão a decidirem sem uma base técnica suficiente,induzindo muitas vezes a decisões equivocadas. Em vista do exposto acima, o objetivodesta pesquisa foi apresentar um método de multicritério (ELECTRE TRI), para avaliar aqualidade ambiental de riachos e compará-lo ao Índice de Integridade Biótica, sendo queambos foram aplicados em afluentes ao Reservatório de Itaipu (rios Ajuricaba, Arroio Fundoe Curvado), utilizando-se a comunidade de peixes como indicador. De acordo com osresultados constatou-se que a escolha do método multicritério para este tipo de trabalho éválida, pois quando comparados com o Índice de Integridade Biótica, os resultados não sedistanciaram. Deste modo...

Benthic macroinvertebrate communities as indicators of river environment quality: an experience in Nicaragua

Fenoglio,Stefano; Badino,Guido; Bona,Francesca
Fonte: Revista de Biología Tropical Publicador: Revista de Biología Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2002 EN
Relevância na Pesquisa
36.27%
Biotic indexes are one of severas types of measures that are routinely used in biological monitoring in temperate streams and offer interesting possibilities to assess the environmental quality of rivers in the neotropics. Macroinvertebrate communities of seven southeastern Nicaraguan streams were monitored and seven ecological indexes were applied. The results suggest that information from the Indice Biótico Esteso (I.B.E.) is closely correlated to the results of other methods, but the I.B.E. index is easier to apply as well as avoiding high costs and time-consuming procedures. A calibration of the method is necessary for rapid assessment approaches in the neotropics.