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  • 1
    Online Resource
    Online Resource
    Invertebrate colonisation during leaf processing of native, exotic and artificial detritus in a tropical stream
    CSIRO Publishing ; 2012
    In:  Marine and Freshwater Research Vol. 63, No. 5 ( 2012), p. 428-
    Details
    In: Marine and Freshwater Research, CSIRO Publishing, Vol. 63, No. 5 ( 2012), p. 428-
    Abstract: The relationship between leaf breakdown and colonisation by invertebrates in tropical aquatic ecosystems is poorly understood, especially in regard to the added problem of the potential effects of exotic species. To assess the colonisation by invertebrates during leaf breakdown in a third-order headwater stream in south-eastern Brazil, we conducted an experiment using the native species Miconia chartacea, the exotic species Eucalyptus grandis and artificial leaves. We hypothesised that the quality of the detritus and the leaf shape influence invertebrate colonisation because of the quality of the food and refuge offered by leaf detritus. Invertebrate density and richness were higher on leaves of E. grandis than on those of M. chartacea. Taxon richness did not differ among M. chartacea and the two sizes of artificial leaves offered, probably as a function of the chemical composition of E. grandis. Total invertebrate density was significantly higher in the organic detritus, suggesting that detritus provides food for the organisms. Our results indicate that the colonisation of invertebrates is probably affected by the chemical composition of detritus. Contrary to expectations, the community of invertebrates had no difficulty in colonising E. grandis, although it is an exotic species. In addition, the shredder activity did not influence leaf breakdown. These results may indicate that the invertebrates in this stream tend to behave as generalist feeders.
    Type of Medium: Online Resource
    ISSN: 1323-1650
    URL: Article
    DOI: 10.1071/MF11172
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2012
    detail.hit.zdb_id: 1283028-8
    SSG: 12
    SSG: 21,3
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  • 2
    Online Resource
    Online Resource
    The additive partitioning of macroinvertebrate diversity in tropical reservoirs
    CSIRO Publishing ; 2013
    In:  Marine and Freshwater Research Vol. 64, No. 7 ( 2013), p. 609-
    Details
    In: Marine and Freshwater Research, CSIRO Publishing, Vol. 64, No. 7 ( 2013), p. 609-
    Abstract: Understanding the ways in which diversity changes across spatial scales is important for the conservation of biodiversity. The objectives of the present study were (1) to characterise the diversity of aquatic macroinvertebrates in three Brazilian tropical reservoirs and (2) to determine how the organisms were distributed at different spatial scales, by using a diversity partitioning approach. We compared the diversity-partition results with the null hypothesis that the macroinvertebrate community was uniform across all spatial scales in the study. We expected that differences in environmental variability (sediment characteristics) among the reservoirs and limitations on the dispersal of organisms among reservoirs result in higher biological variability (β diversity). The results of the spatial partitioning analysis of species richness in the reservoirs showed that each Ekman–Birge dredge-sampling unit (α) represented 43.7% of the total variation. β1 diversity (diversity among Ekman–Birge dredge-sampling units) represented 47.2% of the total variation. A partial Mantel test indicated a correlation between the particle-size matrix and the biological matrix. However, the biological matrix was not correlated with the geographical matrix. The partitioning of overall spatial diversity indicated that the distribution of species in the reservoirs was driven by local factors and that diversity was more pronounced at lower hierarchical levels.
    Type of Medium: Online Resource
    ISSN: 1323-1650
    URL: Article
    DOI: 10.1071/MF12354
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2013
    detail.hit.zdb_id: 1283028-8
    SSG: 12
    SSG: 21,3
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  • 3
    Online Resource
    Online Resource
    Ecoregions and stream types help us understand ecological variability in Neotropical reference streams
    CSIRO Publishing ; 2019
    In:  Marine and Freshwater Research Vol. 70, No. 4 ( 2019), p. 594-
    Details
    In: Marine and Freshwater Research, CSIRO Publishing, Vol. 70, No. 4 ( 2019), p. 594-
    Abstract: Stream site classification is a fundamental step in defining reference conditions for freshwater bioassessments globally. Landscape regionalisation and stream typology approaches have both been used to determine classes that reduce inherent environmental variation and to show classes with ecological meaning. We evaluated the applicability of ecoregion and stream typology approaches in a river basin located between the Neotropical Savanna and the Atlantic Forest biomes in south-eastern Brazil. We delimited two ecoregions and assessed whether stream types within each ecoregion would further reduce environmental and macroinvertebrate assemblage variability. In addition, we determined indicator taxa for each of the reference condition classes. Our results confirm the importance of defining ecoregions a priori and for using a nested a posteriori stream typology approach for further explaining macroinvertebrate assemblage variation. Geology and natural vegetation physiognomy were the key ecoregion factors likely to influence macroinvertebrate assemblages, and stream dimension attributes best delimited meaningful stream types. Although stream classification is a very important step in any monitoring, management or restoration program, it has been widely neglected in many tropical regions. In this study we demonstrated how it can be conducted to determine macroinvertebrate assemblage potentials even with a relatively limited number of sites.
    Type of Medium: Online Resource
    ISSN: 1323-1650
    URL: Article
    DOI: 10.1071/MF18309
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2019
    detail.hit.zdb_id: 1283028-8
    SSG: 12
    SSG: 21,3
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  • 4
    Online Resource
    Online Resource
    Composition and dynamics of allochthonous organic matter inputs and benthic stock in a Brazilian stream
    CSIRO Publishing ; 2009
    In:  Marine and Freshwater Research Vol. 60, No. 10 ( 2009), p. 990-
    Details
    In: Marine and Freshwater Research, CSIRO Publishing, Vol. 60, No. 10 ( 2009), p. 990-
    Abstract: Riparian vegetation provides the nutrient and energy input that maintains the metabolism and biodiversity in tropical headwater streams. In the present study, it was hypothesised that ~30% of riparian plant species contribute over 70% of coarse particulate organic matter and, because tropical plants are perennial and semi-deciduous, it was expected that leaf fall would occur year round. The aims of the present study were to evaluate the composition and structure of the plant riparian zone and the input and associated benthic stock of organic matter. The riparian vegetation was composed of 99 taxa. The most abundant plant species were Tapirira obtusa, Sclerolobium rugosum, Croton urucurana, Byrsonima sp. and Inga sp. The input and benthic stock showed a seasonal pattern, with higher values recorded at the end of the dry season and at the beginning of tropical storms. The biomass contributed monthly by the vegetation ranged from 28 ± 6 g m–2 to 38 ± 11 g m–2, and the mean monthly benthic standing stock was 138 ± 57 g m–2. The results illustrate the importance of riparian vegetation as an energy source to tropical streams and how individual plant species contribute to organic matter inputs in these ecosystems.
    Type of Medium: Online Resource
    ISSN: 1323-1650
    URL: Article
    DOI: 10.1071/MF08247
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2009
    detail.hit.zdb_id: 1283028-8
    SSG: 12
    SSG: 21,3
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  • 5
    Online Resource
    Online Resource
    Regionalisation is key to establishing reference conditions for neotropical savanna streams
    CSIRO Publishing ; 2018
    In:  Marine and Freshwater Research Vol. 69, No. 1 ( 2018), p. 82-
    Details
    In: Marine and Freshwater Research, CSIRO Publishing, Vol. 69, No. 1 ( 2018), p. 82-
    Abstract: Areas with minimal anthropogenic influences are frequently used as reference sites and represent the best ecological state available in a region. Streams in such conditions are necessary for evaluating the conservation status of aquatic ecosystems of a region and to monitor them, taking natural environmental variability into consideration. Therefore, the aim of the present study was to analyse whether hydrological units are reliable regional units for aggregating reference sites. To this end, reference sites were studied in three different landscape units of the same hydrological unit. The study tested the hypothesis that water quality, physical habitat structure and the composition and structure of macroinvertebrate assemblages will be more similar for sites in the same landscape unit than for sites located in different landscape units in the same hydrological unit. The study showed that taxonomic richness and composition of the macroinvertebrate assemblages were negatively affected by site slope and positively affected by the presence of leaf packs on the streambed. The three landscape units supported significantly different macroinvertebrate assemblages and indicator taxa. Therefore, a hydrological unit does not constitute a homogeneous entity in terms of environmental variables and biological composition if it incorporates high landscape heterogeneity. These results should improve and facilitate the selection of reference sites for biomonitoring programs and for managing tropical headwater streams.
    Type of Medium: Online Resource
    ISSN: 1323-1650
    URL: Article
    DOI: 10.1071/MF16381
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2018
    detail.hit.zdb_id: 1283028-8
    SSG: 12
    SSG: 21,3
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