Metrics derived from fish assemblages as indicators of environmental degradation in Cerrado streams

• Published in: Zoologia (Curitiba, Brazil) Vol. 35; pp. 1 - 8
• Main Authors: Ávila, Milton P., Carvalho, Rafaela Neves, Casatti, Lilian, Simião-Ferreira, Juliana, de Morais, Lorrane Faria, Teresa, Fabrício B.
• Format: Journal Article
• Language: English
• Published: Curitiba Sociedade Brasileira de Zoologia 01-01-2018
• Subjects: Aquatic ecosystems; Bioindicators; Biomonitoring; Brazilian savannah; Conservation status; Ecology; Environmental degradation; Environmental impact; Environmental indicators; Environmental quality; Fish; fish fauna; Fisheries management; Habitats; Ichthyofauna; Land cover; Land degradation; multimetric index; Riparian forests; River basins; Rivers; Scientometrics; Streams; Taxonomy; Vegetation; ZOOLOGY; Brazil; Cerrado Biome; Bioindicators; Brazilian savannah; fish fauna; multimetric index
• ISSN: 1984-4689; 1984-4670; 1984-4689
• DOI: 10.3897/zoologia.35.e12895

The development of effective monitoring tools depends on finding sensitive metrics that are capable of detecting the most important environmental impacts at a given region. We assessed if metrics derived from stream fish assemblages reflect physical habitat degradation and changes in land cover. We sampled the ichthyofauna and environmental characteristics of 16 stream sites of first and second order in the Upper Tocantins River basin. The streams were classified according to their environmental characteristics into reference (n = 5), intermediate (n = 4), and impacted (n = 7). A total of 4,079 individuals in five orders, 12 families, and 30 species were collected. Of the 20 metrics tested, eight were non-collinear and were tested for their performance in discriminating among groups of streams. Three metrics were sensitive to the gradient of degradation: Berger-Parker dominance index, percentage of characiform fish, and percentage of rheophilic individuals. Some commonly used metrics did not reflect the disturbances and many others were redundant with those that did. These results indicate that the metrics derived from fish assemblages may be informative for identifying the conservation status of streams, with the potential to be used in biomonitoring.