Affiliation:
1. Universidade Federal do Amazonas, Brazil
2. Instituto Nacional de Pesquisas da Amazônia, Brazil
Abstract
Small streams are important components of the landscape in terra firme forests in central Amazonia and harbor a large number of fish species. Nevertheless, the lack of a common sampling protocol in studies of this ichthyofauna hinders comparisons among available results. This study evaluates how the length of stream reach sampled affects estimates of local fish species density in 1st, 2nd, and 3rd order streams, and proposes a mean minimum sampling length that best approximates the absolute number of species in a given stream segment. We sampled three streams in the Biological Dynamics of Forest Fragments Project's study sites, between May and August 2004. At each stream, one 1st order, one 2nd order, and one 3rd order segment was sampled. We sampled five 20-m reaches in each stream segment. Three to four people collected along each reach for 45 to 60 minutes. We used Jaccard's coefficient to estimate the similarity of species composition among stream reaches and segments. Estimates of species richness were obtained with Jackknife 1 and Bootstrap algorithms and species accumulation curves. We used simple linear regressions to look for relationships between species density and fish abundance and between species density and the volume of 100-m stream segments. Species density in 1st order stream reaches was slightly higher than in 2nd and 3rd order stream reaches, whereas fish abundance was apparently higher in 3rd order reaches. Similarity in fish species composition between 20-m reaches was low for all studied streams. Species density values in pooled 100-m stream segments represented 71.4% to 94.1% of the estimated values for these streams. Species density showed a direct relationship both with volume of the sampled stream segment and fish abundance. It seems plausible that larger streams contain a higher number of microhabitat types, which allow for the presence of more fish species per stream length. Based on the values of asymptotes and equations for species accumulation curves, the mean minimum sampling length that best estimates the absolute number of species in a stream segment is 180 m ± 20 sd for 1st order segments; 213 m ± 23 sd for 2nd order segments, and 253 m ± 30 sd for 3rd order stream segments.
Subject
Aquatic Science,Animal Science and Zoology,Ecology, Evolution, Behavior and Systematics
Reference38 articles.
1. Evolutionary Ecology of Neotropical Freshwater Fishes;Angermeier P. L.,1984
2. Species-area relationships for streams fishes;Angermeier P. L.;Ecology,1989
3. Estimating number of species and relative abundances in stream-fish communities: effects of sampling effort and discontinuous spatial distributions;Angermeier P. L.;Canadian Journal of Fisheries and Aquatic Sciences,1995
4. Relação entre o número de espécies de peixes, complexidade de hábitat e ordem do riacho nas cabeceiras de um tributário do rio Urubu, Amazônia Central;Araújo-Lima C. A. R. M.;Acta Limnologica Brasiliensia,1999
5. Heterogeneidade de habitats: rasos e fundos em assembléias de peixes de igarapés de terra firme na Amazônia Central, Brasil;Buhrnheim C. M.;Revista Brasileira de Zoologia,2002
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