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Search Results: 1 - 10 of 19243 matches for " Cristina;Maltchik "
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Diversity and distribution of aquatic insects in Southern Brazil wetlands: implications for biodiversity conservation in a Neotropical region
Leonardo Maltchik,Marina Schmidt Dalzochiov,Cristina Stenert,Ana Silvia Rolon
Revista de Biología Tropical , 2012,
Abstract: The selection of priority areas is an enormous challenge for biodiversity conservation. Some biogeographic methods have been used to identify the priority areas to conservation, and panbiogeography is one of them. This study aimed at the utilization of panbiogeographic tools, to identify the distribution patterns of aquatic insect genera, in wetland systems of an extensive area in the Neotropical region (~280 000km2), and to compare the distribution of the biogeographic units identified by the aquatic insects, with the conservation units of Southern Brazil. We analyzed the distribution pattern of 82 genera distributed in four orders of aquatic insects (Diptera, Odonata, Ephemeroptera and Trichoptera) in Southern Brazil wetlands. Therefore, 32 biogeographic nodes corresponded to the priority areas for conservation of the aquatic insect diversity. Among this total, 13 were located in the Atlantic Rainforest, 16 in the Pampa and three amongst both biomes. The distribution of nodes showed that only 15% of the dispersion centers of insects were inserted in conservation units. The four priority areas pointed by node cluster criterion must be considered in further inclusions of areas for biodiversity conservation in Southern Brazil wetlands, since such areas present species from differrent ancestral biota. The inclusion of such areas into the conservation units would be a strong way to conserve the aquatic biodiversity in this region. La selección de áreas prioritarias es un enorme desafío para la conservación de la biodiversidad. Métodos biogeográficos se han utilizado para identificar áreas prioritarias para la conservación, como la panbiogeografía. Este estudio tuvo como objetivo el empleo de herramientas panbiogeográficas, para identificar los patrones de distribución de los géneros de insectos acuáticos, en los sistemas de humedales de una extensa área de la región Neotropical (~280 000km2), y así comparar la distribución de las unidades biogeográficas identificadas por los insectos acuáticos, con las unidades de conservación del sur de Brasil. Asimismo, se analizaron los patrones de distribución de los 82 géneros de cuatro órdenes de insectos acuáticos (Diptera, Odonata, Ephemeroptera y Trichoptera) en los humedales del sur de Brasil. Ahora bien, 32 nodos biogeográficos correspondieron a las áreas prioritarias para la conservación de la diversidad de insectos acuáticos. Dentro de este total, 13 se encontraban en el Bosque Atlántico, 16 en la Pampa y tres entre los dos biomas. La distribución de nodos mostró que sólo el 15% de los centros de dispersión de
Three new wetlands inventories in brazil
Interciencia , 2003,
Abstract: the inventories of wetlands provide an indication of the location of the land with the highest biological diversity. in brazil, studies of wetlands stressing the inventory and classification are scarce and three recent inventories have been developed. the establishment of a wetland national inventory in brazil is necessary and could be started in the semiarid region because of the small amount of surface water and non-complexity of aquatic ecosystems. the wetlands inventory and classification must be encouraged in brazil. the classification structure should be composed by different levels arranged in an hierarchical fashion. however, brazil has a long way to go, since basic research related to the wetlands inventory and classification have not been investigated by brazilian researchers.
Diversity and stability of aquatic macrophyte community in three shallow lakes associated to a floodplain system in the south of Brazil
Maltchik,Leonardo; de Oliveira,Gislaine Roberto; Rolon,Ana Silvia; Stenert,Cristina;
Interciencia , 2005,
Abstract: the floodplain systems are important wetland classes in southern brazil, but studies about the effects of flood pulses on the biota are still scarce. the purpose of this study was to analyze and compare the effects of floods on the richness, biomass and diversity of macrophytes in three shallow lakes over an annual cycle (2001-2002) under different flooding regimes. the number of flood events was different among the three studied shallow lakes. the lowest resistance to disturbance by flood and the absence of dominance were observed in the lake with the highest number of flood events. macrophyte stability and diversity were not related. the results indicate the importance of the flooding regime (number of flood events, even short duration ones) on the macrophyte stability and composition in shallow lakes of southern brazil.
Uma nova espécie de Sigara Fabricius (Hemiptera, Heteroptera, Corixidae) e redescri??o das espécies do gênero com registro no Estado do Rio Grande do Sul, Brasil
Bernardo, Larissa P.;Ribeiro, José Ricardo I.;Stenert, Cristina;Maltchik, Leonardo;
Revista Brasileira de Entomologia , 2012, DOI: 10.1590/S0085-56262012005000032
Abstract: a new species of sigara fabricius (hemiptera, heteroptera, corixidae) and redescription of the species recorded in the state of rio grande do sul, brazil. water boatmen (corixidae) constitute the largest group of water bugs, with well over 40 species occurring in brazil. most of the species of sigara are known from the neotropics, and 11 of them have been reported in brazil. little is known about the distribution and taxonomy of sigara species of rio grande do sul. the following seven species are recorded and redescribed: sigara (tropocorixa) chrostowskii, s. (t.) denseconscripta, s. (t.) dita, s. (t.) hungerfordi, s. (t.) platensis, s. (t.) schadei, and s. (t.) townsendi. sigara (t.) dita, s. (t.) hungerfordi, and s. (t.) townsendi are newly recorded from this state, while s. (t.) schadei is recorded for the first time from brazil. sigara (t.) bachmanni, sp. nov. is described from northeastern rio grande do sul. this species resembles s. (t.) hungerfordi in having the synthlipsis less than 0.9 times the width of an eye, metaxyphus broader than long, and the infraocular portion of genae slender, but can be readily recognized by the presence of a short hook at apex of right clasper and serrations along the margin of its pre-apical portion. a key to the species of sigara occurring in rio grande do sul is provided. although the general aspect of right clasper and the number of pegs of male pala as well as its shape have proven useful for species delimitation, s. (t.) chrostowskii and s. (t.) townsendi have shown considerable variation in these features and have been redescribed here.
Can rice field channels contribute to biodiversity conservation in Southern Brazilian wetlands?
Maltchik,Leonardo; Rolon,Ana Silvia; Stenert,Cristina; Machado,Iberê Farina; Rocha,Odete;
Revista de Biología Tropical , 2011,
Abstract: conservation of species in agroecosystems has attracted attention. irrigation channels can improve habitats and offer conditions for freshwater species conservation. two questions from biodiversity conservation point of view are: 1) can the irrigated channels maintain a rich diversity of macrophytes, macroinvertebrates and amphibians over the cultivation cycle? 2) do richness, abundance and composition of aquatic species change over the rice cultivation cycle? for this, a set of four rice field channels was randomly selected in southern brazilian wetlands. in each channel, six sample collection events were carried out over the rice cultivation cycle (june 2005 to june 2006). a total of 160 taxa were identified in irrigated channels, including 59 macrophyte species, 91 taxa of macroinvertebrate and 10 amphibian species. the richness and abundance of macrophytes, macroinvertebrates and amphibians did not change significantly over the rice cultivation cycle. however, the species composition of these groups in the irrigation channels varied between uncultivated and cultivated periods. our results showed that the species diversity found in the irrigation channels, together with the permanence of water enables these man-made aquatic networks to function as important systems that can contribute to the conservation of biodiversity in regions where the wetlands were converted into rice fields. the conservation of the species in agriculture, such as rice field channels, may be an important alternative for biodiversity conservation in southern brazil, where more than 90% of wetland systems have already been lost and the remaining ones are still at high risk due to the expansion of rice production. rev. biol. trop. 59 (4): 1895-1914. epub 2011 december 01.
Of rapid assessment approach to discuss ecological theories in wetland systems, Southern Brazil
Maltchik,Leonardo; Callisto,Marcos;
Interciencia , 2004,
Abstract: the rapid assessment program (rap) constitutes a powerful tool used to select important areas for the conservation of biodiversity. the relationships between species diversity and the ecosystem size have been investigated by biologists, mainly in terrestrial ecosystems. recent biodiversity surveys of algae, macrophytes and macroinvertebrates were developed in the sinos river basin (southern brazil) using the aqua-rap approach as a tool. the selection of wetlands (different size and classes) was fundamental to discuss the relationship between biodiversity and the size of ecosystems. only macrophyte richness was positively correlated to the size of the wetland. the richness of algae and macroinvertebrates was not influenced by the size of the wetlands. these results show the importance of the inclusion of different biological communities to test ecological theories and to propose strategies for conservation programs.
Aquatic macrophyte and macroinvertebrate diversity and conservation in wetlands of the Sinos River basin
Maltchik, L.;Rolon, AS.;Stenert, C;
Brazilian Journal of Biology , 2010, DOI: 10.1590/S1519-69842010000600007
Abstract: wetlands are important sites for biological conservation because they support rich biodiversity and present high productivity. species-area relationship is an important tool in conservation planning and it has been extensively used for wetland management. this study had as aims: (1) to analyse macrophyte and macroinvertebrate diversity in the fragmented wetlands of the sinos river basin; and (2) to investigate whether wetland areas could work as a tool for selecting the important habitats for biodiversity conservation. throughout the study, 56 species of macrophytes and 57taxa of macroinvertebrates were identified. macrophyte richness was related to the wetland area, but macroinvertebrate richness, however, was not related to the wetland area. the macrophyte and macroinvertebrate composition were not related to the wetland area. species composition varied between the regions of the basin and the difference in the species composition occurred mainly by the distribution of macroinvertebrates. with regard to the biodiversity conservation of the sinos river basin, the wetland area must not be a priority criterion for choosing the important wetlands for conservation. the environmental policies for biodiversity conservation must include management actions focused also on the protection of small wetlands. moreover, other criteria should be analysed in further research such as habitat diversity, hydroperiod, geographic distribution and connectivity.
Diversity and stability of fishes (Teleostei) in a temporary river of the Brazilian semiarid region
Medeiros, Elvio S.F.;Maltchik, Leonardo;
Iheringia. Série Zoologia , 2001, DOI: 10.1590/S0073-47212001000100016
Abstract: the effects of hydrological disturbances by flooding and drought on the diversity and stability in a temporary river fish community in the brazilian semiarid region were analyzed over the 1996 hydrological cycle. twelve collections of fishes were made during the wet and dry phases, and 789 individuals of 16 species were collected. diversity was measured using simpson's index (s) and community stability was analyzed by the variation in abundance using kendall's w concordance test. fish diversity in the taperoá river was subjected to hydrological disturbances by flooding and drought. during the wet phase the diversity was higher (s = 0.855) than during the dry phase (s = 0.771). the community was considered stable during the whole annual hydrological cycle (w = 0.418 p < 0.001), but a higher stability in the community was found during the dry phase. during the dry phase the number of dominant species was smaller than during the wet phase.
Hydrologic cycle and dynamics of aquatic macrophytes in two intermittent rivers of the semi-arid region of Brazil
Pedro, F.;Maltchik, L.;Bianchini Jr., I.;
Brazilian Journal of Biology , 2006, DOI: 10.1590/S1519-69842006000400002
Abstract: the dynamics of aquatic macrophytes in intermittent rivers is generally related to the characteristics of the resistance and resilience of plants to hydrologic disturbances of flood and drought. in the semi-arid region of brazil, intermittent rivers and streams are affected by disturbances with variable intensity, frequency, and duration throughout their hydrologic cycles. the aim of the present study is to determine the occurrence and variation of biomass of aquatic macrophyte species in two intermittent rivers of distinct hydrologic regimes. their dynamics were determined with respect to resistance and resilience responses of macrophytes to flood and drought events by estimating the variation of biomass and productivity throughout two hydrologic cycles. twenty-one visits were undertaken in the rewetting, drying, and drought phases in a permanent puddle in the avelós stream and two temporary puddles in the taperoá river, state of paraíba, northeast brazil. the sampling was carried out by using the square method. floods of different magnitudes occurred during the present study in the river and in the stream. the results showed that floods and droughts are determining factors in the occurrence of macrophytes and in the structure of their aquatic communities. the species richness of the aquatic macrophyte communities was lower in the puddles of the river and stream subject to flood events, when compared to areas where the run-off water is retained. at the beginning of the recolonization process, the intensity of the floods was decisive in the productivity and biomass of the aquatic macrophytes in the taperoá river and the avelós stream. in intermediate levels of disturbance, the largest values of productivity and biomass and the shortest time for starting the recolonization process occurred.
Does the Lagoa do Peixe sandbar opening influence the macrophyte richness and composition in Southern Brazil wetlands?
Ana Silvia Rolon,Odete Rocha,Leonardo Maltchik
Revista de Biología Tropical , 2013,
Abstract: The Lagoa do Peixe has its connection with the sea artificially opened every year at the end of winter. However, this management has been carried out without the evaluation of the impact of this opening in the aquatic biodiversity. This information is crucial for the management of the natural resources of the Lagoa do Peixe National Park, the unique Ramsar site in Southern Brazil. The following questions were analyzed: (1) Do richness and composition of aquatic macrophytes from Lagoa do Peixe floodplain varies temporarily according to the sandbar opening and closing? (2) Does the variation pattern of the macrophyte community changed according to the sandbar opening and closing? A set of eight sampling sites of 1ha were selected over the Lagoa do Peixe floodplain: four sites not influenced by the artificial sandbar opening and four sites influenced by this event, being two sites closer to the sandbar opening and the two sites distant to the sandbar opening. The samplings were carried out between November 2007 and October 2009. The results show that although the artificial sandbar breaching does not affect the aquatic macrophyte richness at the floodplain, it affects the dynamics of species composition. The hydrological variation related to this management can be the main factor of the continuous change in the species composition in the floodplain, especially in the Southern portion. In order to avoid impacts in the macrophyte conservation, the artificial sandbar opening should be considered carefully, since the area of study is one of the most important conservation units to wetland systems in Southern Brazil. La Lagoa do Peixe, en el sur de Brasil, tiene conexión artificial con el mar, porque cada a o, al final del invierno, se abre un canal con tractor. Sin embargo, esta práctica se ha levado a cabo sin la evaluación de los efectos de esta apertura en la biodiversidad acuática. Las siguientes preguntas fueron analizadas: (1) Varían la riqueza y la composición de los macrófitos acuáticos de la llanura de inundación temporal de la Lagoa do Peixe según la apertura y el cierre del banco arena? (2) Varía el patrón de la comunidad de macrófitos según la apertura y el cierre del banco de arena? Los resultados muestran que la eliminación artificial del banco de arena no afecta la riqueza de macrófitos acuáticos en la llanura de inundación, pero sí afecta la dinámica de la composición de especies. La variación hidrológica relacionada con la apertura puede ser el factor principal del cambio continuo en la composición de especies en la llanura de inundación, es
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