14 documents found, page 1 of 2
Pervasive gaps in Amazonian ecological research
Carvalho, Raquel L.; Resende, Angelica F.; Barlow, Jos; França, Filipe M.; Moura, Mario R.; Maciel, Rafaella; Alves-Martins, Fernanda; Shutt, JackBiodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain underst...
How are local fish communities structured in Brazilian semiarid headwater streams?
Rodrigues-Filho, Carlos Alberto de Sousa; Gurgel-Lourenço, Ronaldo Cesar; Bezerra, Luis Artur Valões; Oliveira, Edson Fontes de; Leitão, Rafael PereiraEnvironmental and spatial factors are known as the main determinants of community variation in aquatic organisms. However, historical factors may interact with local processes to regulate community structure patterns. Here we compared historical, environmental, and spatial factors in a multi-scale approach in order to identify the main drivers structuring species composition and functional diversity of fish com...
Microhabitat segregation and fine ecomorphological dissimilarity between two cl...
Leitão, Rafael Pereira; Sánchez-Botero, Jorge Ivan; Kasper, Daniele; Cardoso, Victor Trivério; Araújo, Carolina Morais; Zuanon, JansenHabitat segregation is considered the mostprevalent resource-partitioning mechanism for streamfishes and the species morphology can be a strongpredictor of their spatial distribution. However, moststudies addressing morphology-habitat relationshipshave defined the space in physiognomically homoge-neous units (i.e., mesohabitat), probably not detectingsegregation among several closely related species. Herewe inv...
A multiple hypothesis approach to explain species richness patterns in neotropi...
Vieira, Thiago Bernardi; Pavanelli, Carla Simone; Casatti, Lilian; Smith, Welber Senteio; Benedito, Evanilde; Mazzoni, RosanaSeveral hypotheses are used to explain species richness patterns. Some of them (e.g. species-area, species-energy, environment-energy, water-energy, terrestrial primary productivity, environmental spatial heterogeneity, and climatic heterogeneity) are known to explain species richness patterns of terrestrial organisms, especially when they are combined. For aquatic organisms, however, it is unclear if these hyp...
Diet of two syntopic species of crenuchidae (Ostariophysi: Characiformes) in an...
Fernandes, Suzanne; Leitão, Rafael Pereira; Dary, Euriz?ngela Pereira; Guerreiro, Ana Isabel Camacho; Zuanon, Jansen; Bührnheim, Cristina MottaThis study assessed the diet of two poorly known syntopic fish species of the family Crenuchidae, Characidium aff. declivirostre and Leptocharacidium omospilus, in a Presidente Figueiredo’ rocky stream, Amazonas, Brazil. The stomach contents were analyzed and their Frequency of Occurrence (FO %) and Relative Volume (Vol %) were combined in a Feeding Index (IAi). We examined 20 individuals of C. aff. declivirost...
Mercury distribution in different tissues and trophic levels of fish from a tro...
Kasper, Daniele; Palermo, Elisabete Fernandes Albuquerque; Dias, Ana Carolina Monteiro Iozzi; Ferreira, Gustavo Luiz; Leitão, Rafael PereiraConcentrations of organic (OrgHg) and inorganic mercury (InorgHg) were assessed in different fish tissues (liver, muscle, kidney, gut and gonads) and trophic levels collected in an impacted tropical reservoir in southeastern Brazil. Organic mercury concentrations in muscle were remarkably higher in the carnivorous species Hoplias malabaricus and Oligosarcus hepsetus. The ratios of OrgHg in relation to total mer...
Distance to large rivers affects fish diversity patterns in highly dynamic stre...
Stegmann, Lis Fernandes; Leitão, Rafael Pereira; Zuanon, Jansen; Magnusson, William ErnestLongitudinal-zonation hypotheses generally predict gradual changes in fish composition from upstream to downstream due to changes in habitat conditions, but largely disregard downstream effects on upstream segments. Floodplains of large rivers represent areas of high connectivity during flood periods and can act as stable refuges in dry seasons, which may attenuate deterministic constraints imposed by local con...
A multiple hypothesis approach to explain species richness patterns in neotropi...
Vieira, Thiago Bernardi; Pavanelli, C. S.; Casatti, Lilian; Smith, Welber Senteio; Benedito, Evanilde; Mazzoni, Rosana; Sánchez-Botero, Jorge IvánSeveral hypotheses are used to explain species richness patterns. Some of them (e.g. species-area, species-energy, environment-energy, water-energy, terrestrial primary productivity, environmental spatial heterogeneity, and climatic heterogeneity) are known to explain species richness patterns of terrestrial organisms, especially when they are combined. For aquatic organisms, however, it is unclear if these hyp...
Disentangling the pathways of land use impacts on the functional structure of f...
Leitão, Rafael Pereira; Zuanon, Jansen; Mouillot, David; Leal, Cecília Gontijo; Hughes, Robert Mason; Kaufmann, Philip Robert; Vill?ger, S?bastienAgricultural land use is a primary driver of environmental impacts on streams. However, the causal processes that shape these impacts operate through multiple pathways and at several spatial scales. This complexity undermines the development of more effective management approaches, and illustrates the need for more in-depth studies to assess the mechanisms that determine changes in stream biodiversity. Here we ...
Openings of the sand bar in the coastal lagoon imboassica (Rio de Janeiro State...
Sánchez-Botero, Jorge Iván; Garcez, Danielle Sequeira; Leitão, Rafael Pereira; Trivério-Cardoso, Victor; Hollanda Carvalho, PedroThe coastal lagoon Imboassica (Rio de Janeiro State) had from 1993 to 2004 four openings of the sand bar that separates it from the ocean. During this period, 28 samples of fish fauna occurred; 55.6% with commercial value classified in functional guilds as: residents of coastal lagoons (RLC), marine dependent (MD), marine visitors (VM) and from freshwater (D). The catch per unit effort CPUE from the fish specie...