The influence of natural and anthropic environmental variables on the structure and spatial distribution along longitudinal gradient of macroinvertebrate communities in southern Brazilian streams.
Bottom Line: A total of 42 families and 129 taxa were found, with predominance of environmentally tolerant taxa.However, changes in anthropic variables were not affected by these geological differences and therefore did not correlate with patterns of spatial distribution in macroinvertebrate communities.Richness as a whole tended to be higher in 3(rd) to 4(th) order set of segments, but this trend was a result of local anthropic environmental disturbances.
Affiliation: Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria. Faixa de Camobi km 9, 97105-900, Santa Maria, RS, Brazil email@example.com.Show MeSH
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Mentions: No significant differences in richness were recorded among the microbasins at family and lower taxonomic classification levels (TRR: 30 families and 84 lower classifications; VMR and IMR: both 28 families, and 81 and 70 lower classifications respectively). However, the rarefaction test showed higher estimated richness for the TRR and IMR microbasins (there was wide overlapping between confidence intervals), for a comparable sample, i.e., there was higher richness in the TRR and IMR microbasins than the VMR microbasin (Figure 2A). The rarefaction method also determined that 3rd and 4th order segments showed higher richness (25 and 28 families, and 72 and 75 lower taxonomic classifications, respectively) than the 1st and 2nd order segments (31 and 22 families, and 63 and 67 lower taxonomic classifications, respectively) (Figure 2B).
Affiliation: Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria. Faixa de Camobi km 9, 97105-900, Santa Maria, RS, Brazil firstname.lastname@example.org.