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The ecology of Egeria densa Planchón (Liliopsida: Alismatales): A wetland ecosystem engineer?
YARROW,MATTHEW; MARíN,VíCTOR H; FINLAYSON,MAX; TIRONI,ANTONIO; DELGADO,LUISA E; FISCHER,FERNANDA;
Revista chilena de historia natural , 2009, DOI: 10.4067/S0716-078X2009000200010
Abstract: egeria densa planchón is considered an invasive species in continental aquatic systems in chile. its original geographical distribution was limited to the subtropical regions of brazil, argentina and uruguay. its fast growth and dense canopy-forming habit are associated with the clear water state of shallow water continental ecosystems. as a dominant species in many of the systems in which it occurs, e. densa behaves as an ecosystem engineer by preventing the re-suspension of sediments and controlling the growth of phytoplankton by removing nutrients from the water column. at the same time, this invasive species produces unwanted effects such as: (1) clogging waterways and hydroelectric turbines, (2) out-competing native vegetation, and (3) negatively affecting the sediment seed bank. given its importance in the recent (2004) change of state of the río cruces wetland, chile, we felt it appropriate to undertake a comprehensive literature review of this species. we conclude by discussing the role of e. densa as an ecosystem engineer while cautioning against the impression that e. densa is always a highly competitive invader.
The ecology of Egeria densa Planchón (Liliopsida: Alismatales): A wetland ecosystem engineer? La ecología de Egeria densa Planchón (Liliopsida: Alismatales): Una especie ingeniera de humedales?  [cached]
MATTHEW YARROW,VíCTOR H MARíN,MAX FINLAYSON,ANTONIO TIRONI
Revista chilena de historia natural , 2009,
Abstract: Egeria densa Planchón is considered an invasive species in continental aquatic systems in Chile. Its original geographical distribution was limited to the subtropical regions of Brazil, Argentina and Uruguay. Its fast growth and dense canopy-forming habit are associated with the clear water state of shallow water continental ecosystems. As a dominant species in many of the systems in which it occurs, E. densa behaves as an ecosystem engineer by preventing the re-suspension of sediments and controlling the growth of phytoplankton by removing nutrients from the water column. At the same time, this invasive species produces unwanted effects such as: (1) clogging waterways and hydroelectric turbines, (2) out-competing native vegetation, and (3) negatively affecting the sediment seed bank. Given its importance in the recent (2004) change of state of the Río Cruces wetland, Chile, we felt it appropriate to undertake a comprehensive literature review of this species. We conclude by discussing the role of E. densa as an ecosystem engineer while cautioning against the impression that E. densa is always a highly competitive invader. Egeria densa Planchón es considerada una especie invasora en los sistemas acuáticos de Chile. Su distribución geográfica original estaba limitada a regiones subtropicales de Brasil, Argentina y Uruguay. Su crecimiento rápido y su tendencia a formar densas coberturas suelen estar asociadas con el estado de aguas claras en ecosistemas acuáticos continentales de aguas someras. Su dominancia sugiere que E. densa puede comportarse como una especie ingeniera, previniendo la resuspensión de sedimentos y controlando el crecimiento del fitoplancton a través de la utilización de los nutrientes. Sin embargo, al mismo tiempo, como especie invasora produce efectos no deseados tales como: (1) no permitir el crecimiento de otras macrófitas nativas, (2) disminuir la diversidad en el banco de semillas, y (3) interferir con la navegación y generación de electricidad por turbina. Dada su importancia en el reciente (2004) cambio de estado del humedal del Río Cruces, nos ha parecido oportuno realizar una recopilación de artículos científicos disponibles en la literatura sobre esta macrófita. Concluimos con una discusión sobre el rol de E. densa como especie ingeniera; a la vez que indicamos que la especie tiene ciertas vulnerabilidades y que no cumple siempre con la idea que es una especie invasora muy competitiva.
Effects of temperature on decomposition of a potential nuisance species: the submerged aquatic macrophyte Egeria najas planchom (Hydrocharitaceae)
Carvalho, P;Thomaz, S. M.;Bini, L. M.;
Brazilian Journal of Biology , 2005, DOI: 10.1590/S1519-69842005000100008
Abstract: decomposition of aquatic plants is influenced by several biotic and abiotic factors. among them, temperature plays an important role. despite the increasing number of studies describing the effects of temperature on the decomposition of aquatic macrophytes, little attention has been given to the decay of submerged macrophytes. in this paper, we assessed the effect of temperature on weight loss and chemical composition of detritus of the submerged aquatic macrophyte egeria najas planchon (hydrocharitaceae). fresh plant material was maintained at 17oc and 27oc, in the dark, in incubation chambers. the overall decay process was best described by a linear model, with rates of 0.014 day-1 (r2 = 94%) and 0.045 day-1 (r2 = 96%) obtained at 17oc and 27oc, respectively. the analysis of covariance (ancova) indicated a significant difference between the decomposition rates at the two temperatures. the rapid breakdown of e. najas detritus, indicated by the decay coefficient, may be explained by its low content of resistant compounds such as cellulose and lignin. the variables analyzed in this study (ph, electrical conductivity, dissolved oxygen in the water and organic matter, total nitrogen and total phosphorus concentration in detritus) showed accentuated responses at 27oc. it is likely that the higher temperature increased microbial activity and, therefore, oxygen consumption in the water, consequently affecting the ph and the rate of ion and nutrient liberation into the aquatic ecosystem. due to the rapid decomposition of e. najas at high temperatures, a small exportation is expected of this species from its stands to distant regions in tropical reservoirs, where it is considered a potential nuisance species.
Potencial de biossor??o do zinco pela macrófita egeria densa
Módenes, Aparecido Nivaldo;Pietrobelli, Juliana Martins Teixeira de Abreu;Qui?ones, Fernando Rodolfo Espinoza;Suzaki, Pedro Yahico Ramos;Alflen, Vanessa Lizeria;Klen, Márcia Regina da Silva Fagundes;
Engenharia Sanitaria e Ambiental , 2009, DOI: 10.1590/S1413-41522009000400006
Abstract: in this paper, the removal potential on zn ion by macrophyte egeria densa has been studied. the influence of the metal solution ph, the plant drying and the metal solution temperature, and biosorbent grain size was previously studied in batch systems. adsorption kinetic and equilibrium experiments of metals onto e. densa were performed under controlled temperature and permanent shaking. in adsorption kinetic tests for zn (ii) the equilibrium time was around 45 min. the biosorption kinetic data were well fitted by a pseudo-second order model. the equilibrium data at ph 5 were described a rather better by the langmuir isotherm than the freundlich one, with an adsorption rate and maximum metal content values of 0,829l g-1and 0,92 mequiv g-1, respectively, for langmuir model. the macrophytes e. densa could be used as biosorbent material in industrial effluent treatment system.
Controle de Egeria densa e Egeria najas em caixa-d'água utilizando o herbicida diquat
Martins, D.;Velini, E.D.;Negrisoli, E.;
Planta Daninha , 2005, DOI: 10.1590/S0100-83582005000200029
Abstract: the aim of this research was to evaluate the control of egeria densa and egeria najas, using the herbicide diquat. the herbicide doses used for both species were: 0.1; 0.25; 0.5; 1.0; and 1.5ppm. tanks with 0.60x1.10m dimension constituted the plots. visual evaluation at 5, 7, 10, 14, 26, 31, 38, and 45 days after herbicide application was performed through percentage score scale, with 100% corresponding to total plant control. for egeria najas, 0.5 ppm of diquat was sufficient to determine total plant control, with no posterior occurrence of sprouts. for egeria densa, sprouts occurred 45 days after herbicide application with highest intensity at the lowest doses. reapplication doses of 0.5ppm also determined death of the plants.
Sensibilidade de diferentes acessos de Egeria najas e Egeria densa aos herbicidas diquat e fluridone
Martins, D.;Trigueiro, L.R.C.;Domingos, V.D.;Terra, M.A.;Costa, N.V.;
Planta Daninha , 2007, DOI: 10.1590/S0100-83582007000200015
Abstract: the occurrence of new aquatic weed genotypes belonging to the egeria genus led to the development of this work, aimed to evaluate the behavior of different accesses of e. densa and e. najas in response to treatment with the herbicides diquat and fluridone. accesses of different e. densa biotypes from jupiá, nova, avanhandava, promiss?o and salto grande reservoirs and of different e. najas biotypes from jupia, três irm?os, ilha solteira and ibitinga reservoirs were evaluated. the experiment was arranged in a randomized complete design with five replications. the treatments and concentrations used in the e. densa and e. najas studies were: diquat (reward 240 g l-1) at 0.5 and 1.0 mg l-1 with reapplication 12 days after the first application, with fluridone concentration maintained between 3 and 20 mg l-1, and a control without herbicide application. both species were efficiently controlled by one or two applications of diquat, with both concentrations being efficient; however, the accesses studied presented a differentiated response to the herbicide concentrations. the species and accesses studied also behaved in a differentiated way in response to fluridone action, with medium to highly susceptible accesses occurring in both species.
Removal of Copper Ions by Non-living Aquatic Macrophytes Egeria Densa  [PDF]
Juliana Martins Teixeira de Abreu Pietrobelli,Aparecido Nivaldo Módenes,Fernando Rodolfo Espinoza-Qui?ones,Márcia Regina Fagundes-Klen
Bioautomation , 2009,
Abstract: In this work, the removal potential of Cu2+ ions by non-living macrophytes Egeria densa has been studied. Adsorption kinetic and equilibrium tests were carried out in flasks under batch operations and controlled pH and temperature. The biosorption kinetic results have shown that Cu2+ ions removal rate was at its maximum at the beginning of the process. The equilibrium state was achieved after 60 min, and the Cu2+ ions removal was higher than 70% for the given experimental conditions. The kinetic biosorption data were better fitted by using a pseudo second order model. The equilibrium data at pH 5 were better described by the Langmuir isotherm than the Freundlich one, with a maximum metal content value of 1.47 mequiv g-1 and an adsorption rate value of 3.73 l mequiv-1. The kinetic parameters values were in agreement with other biosorbents data published in the literature, indicating that the macrophytes E. densa have a good potential to be used as biosorbent material in industrial effluent treatment system.
Diferencia??o entre Egeria densa e Egeria najas pelos caracteres anat?micos foliares
Rodella, R.A.;Costa, N.V.;Costa, L.D.N.C.;Martins, D.;
Planta Daninha , 2006, DOI: 10.1590/S0100-83582006000200002
Abstract: seven leaf blade quantitative anatomic characters were used to differentiate five accesses of egeria densa, and three accesses of egeria najas, collected in 'jupiá', 'salto grande', 'três irm?os', 'promiss?o', 'nova avanhandava' and 'ibitinga' reservoirs, in relation to leaf blade descriptive and quantitative anatomic characteristics, in order to obtain a better understanding the relations among these anatomic structures and herbicide penetration and translocation. another objective was to provide identification of susceptible and resistant accesses to some chemical products. leaf samples were collected, fixed in faa 50, infiltrated in glycol metacrylate resin, cut transversally with 8 mm of thickness, and stained with toluidine blue. the following leaf anatomic middle vein characters were quantitatively evaluated (%): adaxial and abaxial epidermis, vascular bundle and parenchyma. in the region between the vein and the leaf margin, the % adaxial and abaxial epidermis and leaf thickness were evaluated. the quantitative anatomic characters of the leaf were submitted to statistic multivariate methods of cluster analysis and principal components analysis. results showed that three groups were formed according to similarity levels: group 1 - three accesses of e. najas; group 2 - four accesses of e. densa; group 3 - one access of e. densa. the anatomic characters with high discriminatory degree were: % vascular bundle and abaxial epidermis of middle vein, and % adaxial and abaxial epidermis of the region between the vein and leaf margin. in conclusion, it was observed that the quantitative anatomic characters were determinant in differentiating accesses and aquatic weed species; however, further studies must be conducted to relate the anatomical structures to resistance and susceptibility to herbicides.
Utiliza o da elódea (Egeria densa) na alimenta o de suínos = The use of pondweed (Egeria densa) in pig feed
Wilson Moreira Dutra Júnior,Deorlanda Maria da Silva Carvalho,Carlos B?a-Viagem Rabello,Maria do Carmo Mohaupt Marques Ludke
Acta Scientiarum : Animal Sciences , 2009,
Abstract: O objetivo deste trabalho foi avaliar o desempenho zootécnico, orendimento de carca a e a viabilidade econ mica da inclus o da elódea brasileira (Egeria densa) em ra es para suínos nas fases de crescimento e termina o. Foram utilizadas 32 fêmeas suínas, linhagem comercial Dalland C-40, com peso vivo inicial de 23 ± 1,05 kg, distribuídos em delineamento inteiramente ao acaso. Os tratamentos experimentais consistiram de quatro ra es isoenergéticas e isoproteicas com níveis crescentes de inclus o da elódea (0, 5, 10 e 15%). A inclus o da elódea influenciou de forma quadrática o consumo de ra o, reduziu linearmente o ganho de peso médio diário eaumentou linearmente a convers o alimentar. O peso de carca a quente o rendimento de carca a e a espessura de toucinho apresentara comportamento linear decrescente. A ingest o de cádmio n o provocou toxidez nos animais e nem afetou a sua concentra o no fígado e rins. A viabilidade econ mica em fun o do peso vivo e do peso da carca a quente apresentou comportamento quadrático. Conclui-se que ainclus o de elódea representou piora na convers o alimentar e no ganho de peso, porém economicamente é viável incluí-la até 6,5% na ra o de fêmeas suínas nas fases de crescimento e termina o. The purpose of this study was to evaluate the performance livestock, carcass yield and economic viability of including Brazilian elódea (Egeria densa) in feed for pigs during the growing and finishingphases. We used 32 females, Dalland C-40 commercial line, with initial body weight of 23 ± 1.05 kg, distributed in a completely randomized design. The experimental treatments consisted of four isocaloric and isonitrogenous diets with crescents levels of inclusion of elodea (0, 5, 10 and 15%). The inclusion of elodea took one quadratic effect of the feed intake, decreased linear of the average daily weight gain and increased linearly the feedconversion. The variables of carcass only the hot carcass weight, carcass yield and backfat thickness showed decreasing linear behavior. The intake of cadmium did not cause toxicityin animals and neither led their concentration in the liver and kidneys. The economic viability as a function of body weight, and the hot carcass weight, showed a quadratic. It was concluded that the inclusion of elodea decrease feed conversion and weight gain, but iseconomically viable its inclusion up to 6.5% in females swine rations.
Adjuvantes e herbicidas e a infectividade de Fusarium graminearum, agente potencial de biocontrole de Egeria densa e Egeria najas
Borges Neto, C.R.;Pitelli, R.A.;
Planta Daninha , 2004, DOI: 10.1590/S0100-83582004000100010
Abstract: the effects of adding adjuvants and their association with herbicides on fungus infectivity were studied in the fusariumgraminearum x egeria spp. pathosystem. healthy egeriadensa and e. naja plants were inoculated with suspension of ground rice with f. graminearum, at a concentration of 0.7 g l-1. the assay tubes with the plants immersed in the suspension were kept in the incubator at the temperature of 25 oc and photoperiod of 12 hours daily, with plant symptoms being evaluated every two hours and plant growth monitored based on fresh matter increase at the end of the experiment. the effect of 14 adjuvants and 6 herbicides added to the inoculum on the action of f. graminearum against e. densa and e. najas was evaluated. in general, the adjuvants improved bioherbicide efficiency and the herbicide + fungus association increased disease severity and plant growth control.
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