Colonization of rocky and leaf pack substrates by benthic macroinvertebrates in a stream in southeast Brazil (original) (raw)
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Colonization routes of benthic macroinvertebrates in a stream in southeast Brazil
2006
Colonization routes of benthic macroinvertebrates in a stream in southeast Brazil. The colonization of the benthic substrate by macroinvertebrates of a tropical stream was investigated through four routes: downstream movement, upstream movement, movement from the subsurface and colonization by aerial source. Traps were built and installed to quantify separately each route. Samples were removed after 1, 3, 7, and 21 days of colonization. The community showed two main characteristics: the dominance of two groups (Chironomidae and Baetidae) and a progressive increase in richness and density in a temporal scale. Although this dominance occurred at all routes, they differed in relation to the total richness, total density, community composition, and over time. The density of the main groups sampled differed significantly among routes only at the 21st colonization day. When considered the percentage density by each route (only at 21 colonization day) for the ten most common taxonomic groups, three patterns can be pointed out. (1) Seven taxa used the four routes (Chironomidae, Trichoptera, Baetidae, Leptophlebiidae, Copepoda, Leptohyphidae and Elmidae), (2) one taxa used three routes (Annelida), and (3) two taxa used only two routes (Simuliidae and Glossosomatidae). In this study, the four colonization routes were important for replacement of denuded areas. Groups of benthic macroinvertebrates, which used preferential routes, determined the differences in community structure between different colonization routes.
Colonization of leaf litter by aquatic macroinvertebrates: a study in a low order tropical stream
2007
Colonization of leaf litter by aquatic macroinvertebrates: a study in a low order tropical stream. The streambed of low order tropical streams is composed mainly by dead leaves and tree branches originated from riparian forest. This substratum is decomposed by physical, chemical and biological factors, and can be colonized by a characteristic fauna. The colonization dynamics of these substrates by macroinvertebrates can reflect how they use the multidimensional space of the environment. This work aimed to investigate if the colonization of leaf litter by macroinvertebrates depends of the composition of leaf litter. Three representative species of the riparian forest of the Fazzari stream, in São Carlos, SP, were chosen: Cecropia pachystachya, Calophyllum brasiliensis, and Talauma ovata. Four treatments were used, with leaf litter bags containing leaves of each isolated species and a fourth treatment with a mixture of the species. Replicated bags were placed into the stream, and recovered after 7, 21 and 35 days. The colonizing fauna was analyzed in relation to the taxonomic structure, relative taxon abundance, and functional structure (feeding guilds). Only C. brasiliensis presented differences of faunal colonization in relation to the other treatments, with fewer taxa (12) and functional feeding groups, and the lowest abundance of colonizing individuals (80). T. ovata and the mixed substratum were mainly colonized by macroinvertebrate shredders (e.g., Endotribelos spp. and Phylloicus sp.), presenting the greatest number of taxa (23 and 21), and abundances (357 and 271). These patterns suggest that leaf litter colonization was strongly influenced by the quality of the resources represented by leaves from different tree species.
Community Ecology, 2021
The introduction of exotic species can generate changes in the composition of organic debris of alien origin in aquatic ecosystems close to the places of introduction. This new debris can cause impacts at the level of communities and ecosystems. Therefore, the present work aims to answer the following question: are the macroinvertebrate communities present in substrates formed by leaves of the exotic species Pinus caribaea Morelet (Pinaceae) and Eucalyptus grandis Hill ex Maiden (Myrtaceae) similar to those found in substrates composed by the mix of these two species and substrates composed by a mix of native species? For the collection of macroinvertebrates, sets of four types of artificial substrates were submerged in a stream inside the Ecological Station of Panga (Uberlândia—MG, Brazil). The treatments were: leaves of P. caribaea, leaves of E. grandis, leaves of both exotic species and leaves of two native species. In the 20 sample units, about 250 individuals were found, belonging to the orders Coleoptera, Diptera, Ephemeroptera, Heteroptera, Megaloptera, Odonata, Plecoptera and Trichoptera. The effects of the treatments were observed in the exponential decay of the substrate mass and in the structure of the benthic macroinvertebrates communities. The composition of these communities differed among treatments, with high dissimilarity observed between P. caribaea treatments and the mix of exotic species. Therefore, the results demonstrate the importance of substrate complexity for benthic macroinvertebrates, as well as the possible effects of biological invasion and co-invasion by species widely used in silviculture activities.
Colonization of benthic invertebrates in a stony river in Southern Brazil
2020
Os amostradores artificiais e naturais sao ferramentas importantes para demonstrar a diversidade biologica, bem como o processo de sucessao ecologica que ocorre em ambientes loticos. Assim, o objetivo deste trabalho foi verificar o processo de colonizacao em substratos naturais e artificiais em periodos seco e chuvoso no Rio Palmital (Uniao da Vitoria, Parana, Brasil). Para verificar os efeitos da estacao chuvosa na comunidade e o uso de Amostradores artificiais em estudos ecologicos com a comunidade bentonica. Os amostradores (n = 32) foram dispostos em um trecho longitudinal (16 amostradores naturais e 16 artificiais). Duas replicas de cada amostrador foram tomadas no 2o, 4o, 7o, 14o, 21o, 28o, 35o e 42o dias de colonizacao. Os organismos foram identificados e analisados para analises faunisticas. Um total de 513 invertebrados foram coletados, sendo 254 coletados em substrato artificial e 259 em substrato natural. A diversidade da comunidade dos invertebrados bentonicos foi maior ...
Distribution of benthic macroinvertebrates in Subtropical streams (Rio Grande do Sul, Brazil)
2009
Aim: The aim of this study was to evaluate the spatial and seasonal distribution of the benthic macroinvertebrates community in streams in the north region of Rio Grande do Sul State; Methods: The samplings were carried out in nine streams, in annual seasons. The organisms were collected with a Surber sampler (250 µm mesh; area: 0.1 m²). Environmental variables were measured to verify influences in the benthic community using a Canonical Correspondence Analysis. To evaluate the differences among communities, density, richness, diversity and evenness an ANOVA was used. To compare benthic fauna composition a MANOVA was used; Results: The environmental variables showed significant differences among the streams; however the seasons not differ. The density of organisms was significantly different among the streams and the diversity was different among the seasons. Richness and evenness not showed spatial-seasonal differences. The canonical correspondence analysis explained 67.4% of the data total variability. The main variables that influenced the benthic community were the nutrients contents, pH, electric conductivity and substrate organic matter; Conclusions: Streams with riparian vegetation and lower contents of dissolved nutrients showed higher richness of intolerant organisms to pollution. The results suggest that the distribution of benthic macroinvertebrates in the studies region was mainly related to anthropic activities developed in the catchment.
Hydrobiologia, 2006
Leaf litter is a major basal resource to stream ecosystems, but few studies addressed their role in karst systems, mainly in intermittent springs and lakes. Patterns of resource use in perennial rivers are poorly known, although the input of leaf litter strongly influences macroinvertebrate assemblage structure. In this study, we evaluated the structure of macroinvertebrate assemblages along the decomposition of leaf litter in a tropical karst river, using leaf litter cages made of coarse nylon mesh (25 mm) to allow colonization by macroinvertebrates. The experiment was followed weekly for 10 weeks. The assemblages were dominated by snails (90.5% of total fauna), hyalellid amphipods, and larval chironomid midges, with highest abundances in the intermediate stages of the experiment, resulting in a gradient in assemblage structure. The large abundance of snails, which are common in other karst systems, suggest that this group may have an important role in decomposer food webs, facilitating or directly contributing to leaf breakdown.
The effect of substrate texture on colonization by stream macroinvertebrates
Annales de Limnologie - International Journal of Limnology, 2003
The effect of substrate texture on colonization by stream macroinvertebrates was studied in a mountain stream. Experimental patches made of natural substrate, with two levels of cobble and gravel texture (rough and smooth), were subjected to two colonization periods (two hours and one week) within a riffle. Cobble texture affected the number of individuals and taxa colonizing substrate patches, although these relationships depended on time of colonization and some local environmental factors. Texture influence was different for different taxa, and only affected the scraper functional feeding group after one week of colonization, probably in relation to the development of an epilithic layer. These results suggest a significant effect of the surface texture of substrate on colonization by macroinvertebrates, although the effect is complex and needs more careful examination.
We selected streams located in northeastern Brazil with the objective of assessing the effect of streams of different orders (1 st , 2 nd , 3 rd) on the distribution and composition of benthic macroinvertebrates in the rainy and dry seasons. A total of 12822 individuals and 62 taxa of benthic macroinvertebrates were obtained, of which Chironomidae was the taxon with the most individuals (60.08% of the total). The benthic macroinvertebrate assemblage ordination demonstrated that streams of the 3 rd order had a different assemblage structure compared to streams of the 1 st and 2 nd order. This distinction may be the result of taxa substitution. The benthic macroinvertebrate assemblage structure was correlated with environmental variables. In conclusion, the variation of the environmental characteristics according to stream order was the most important factor in benthic macroinvertebrate assemblage organisation and replacement of taxa in the streams investigated. [Keywords: composition, distribution, dry and rainy seasons, Chironomidae, replacement of taxa] RESUMEN. Distribución de la comunidad de macroinvertebrados bentónicos en arroyos tropicales de diferentes órdenes en el noreste de Brasil. Se seleccionaron arroyos localizados en el noreste de Brasil con el objetivo de evaluar el efecto de arroyos de diferente orden (1°, 2° y 3 r) sobre la composición y la distribución de macroinvertebrados bentónicos durante las estaciones seca y lluviosa. Se obtuvo un total de 12822 individuos y 62 taxones de macroinvertebrados bentónicos, entre los cuales Chironomidae fue el taxón con mayor número de individuos. La distribución de este grupo de macroinvertebrados bentónicos demostró que los arroyos de 3 r orden tienen una estructura de comunidad diferente en comparación a los arroyos de 1° y 2° orden. Esta distribución parecería ser el resultado de la sustitución de los taxones. La estructura de la comunidad de macroinvertebrados bentónicos estuvo correlacionada con las variables ambientales. En conclusión, la variación de las características ambientales de acuerdo con el orden del arroyo fue el factor más importante en la organización de la comunidad de macroinvertebrados bentónicos y la sustitución de los taxones en los arroyos investigados.