Encontrados 18 documentos, a visualizar página 1 de 2
The effect of temperature on leaf decomposition and diversity of associated aqu...
Gonçalves, Ana Lucia; Graça, Manuel A. S.; Canhoto, CristinaWe examine the relative importance of substrate quality and temperature in the establishment of aquatic hyphomycete assemblages and in their ability to decompose leaves. We used leaves of alder (Alnus glutinosa) and oak (Quercus robur) and we tested four temperatures (5 , 10 , 15 and 20 C). Differences in decomposition rates and fungal assemblages were higher substrata than across temperatures. In both speci...
Evaluation of stream ecological integrity using litter decomposition and benthi...
Castela, José; Ferreira, Verónica; Graça, Manuel A. S.Biomonitoring programs to access the ecological integrity of freshwaters tend to rely exclusively on structural parameters. Here we evaluated stream ecological integrity using (a) benthic macroinvertebrate derived metrics and a biotic index as measures of structural integrity and (b) oak litter decomposition and associated fungal sporulation rates as measures of functional integrity. The study was done at four ...
Tipologia de rios em Portugal Continental no âmbito da implementação da Directi...
Alves, Maria Helena; Ferreira, João; Pádua, João; Martins, João Pedro; Rafael, Teresa; Tomaz, Gonçalo; Figueiredo, Hélio; Bernardo, João ManuelOs tipos são grupos de massas de água com características geográficas e hidrológicas relativamente homogéneas, consideradas relevantes para a determinação das condições ecológicas. O objectivo da definição de tipos é permitir que sejam correctamente estabelecidas condições de referência e que sejam comparáveis as classificações de estado ecológico dentro de cada grupo de rios com características semelhantes. Na...
Leaf litter as a possible food source for chironomids (Diptera) in Brazilian an...
Callisto,Marcos; Gonçalves Jr,José F.; Graça,Manuel A. S.Our objective was to evaluate the potential use of leaf detritus by chironomid larvae. Field and laboratory experiments were performed using leaves and chironomid species collected in Portugal and Brazil. Laboratory experiments under controlled conditions were done using microbial conditioned senescent leaves of Alnus glutinosa (L.) Gaertn, Neriumoleander L., Protium heptaphilum (Aubl.) March, Protium brasilien...
Fungal Activity Associated with Decomposing Wood is Affected by Nitrogen Concen...
Ferreira, Verónica; Graça, Manuel A. S.We examined the effect of two contrasting nitrogen concentrations in water (0.16 and 0.82 mg L-1) in the mass loss of pre-conditioned balsa wood, and associated fungal activity, in a laboratory microcosm experiment. Contrary to our predictions given the poor nutrient quality of balsa wood, an increase in dissolved nitrogen concentration did not result in increased mass loss or microbial oxygen consumption. Coni...
Decomposition of Fire Exposed Eucalyptus Leaves in a Portuguese Lowland Stream
Gama, Mafalda; Gonçalves, Ana Lúcia; Ferreira, Verónica; Graça, Manuel A. S.; Canhoto, CristinaWe compared fire exposed with normal abscised eucalyptus leaves incubated in a stream running through eucalyptus plantations in central Portugal, in terms of breakdown rates, microbial activity, diversity and macroinvertebrate abundance. Although leaves exposed to fire had lower nutritional value, mass loss was similar for both leaf types (k = 0.0089-0.0095 d-1 for fire and k = 0.0084-0.00103 d-1 for normal lea...
A predictive model for freshwater bioassessment (Mondego River, Portugal)
Feio, Maria; Reynoldson, Trefor; Ferreira, Verónica; Graça, ManuelAbstract We sampled macroinvertebrates at 75 locations in the Mondego river catchment, Central Portugal, and developed a predictive model for water quality assessment of this basin, based on the Reference Condition Approach. Sampling was done from June to September 2001. Fifty-five sites were identified as “Reference sites” and 20 sites were used as “Test sites” to test the model. At each site we also measured...
Testing the Use of the Water Milfoil ( Myriophyllum spicatum L.) in Laboratory ...
Sánchez, David; Graça, Manuel; Canhoto, JorgeAbstract Tests aiming to determine the toxic properties of compounds discharged into aquatic systems have relied more on fish or invertebrates than on primary producers and among a number of producers; algae are the most popular test organisms. Macrophytes are important ecological elements in freshwaters and are therefore potentially key organisms for use in toxicity testing of compounds suspected of acting in...
A laboratory study on feeding plasticity of the shredder Sericostoma vittatum R...
Carvalho, Emerson; Graça, ManuelAbstract Since litter input and availability of leaves in many streams is highly seasonal in Portugal, we investigated whether Sericostoma vittatum, a typical shredder, was able to grow using alternative food sources. To test this hypothesis we fed S. vittatum with Alnus glutinosa (alder, CPOM, coarse particulate organic matter), leaf powder from A. glutinosa and Acacia dealbata and FPOM (fine particulate orga...
Do Invertebrate Activity and Current Velocity Affect Fungal Assemblage Structur...
Ferreira, Verónica; Graça, Manuel A. S.In this study we assessed the effect of current velocity and shredder presence, manipulated in artificial channels, on the structure of the fungal assemblage colonizing alder (Alnus glutinosa (L.) Gaertner) leaves incubated in coarse and fine mesh bags. Fungal sporulation rates, cumulative conidial production and number of species of aquatic hyphomycetes were higher in leaves exposed to high rather than to low ...
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