Environmental determinants of fish species occurrence in headwaters streams of Ivinhema river basin, upper Paraná river - DOI: 10.4025/actascibiolsci.v29i2.520

Abstract

In order to quantify the importance of some physiographic characteristics of headwaters streams of Ivinhema basin on occurrence of four Characidae species, bimonthly samples in 10 streams using a rectangular sieve, with standardized sampling effort were collected. The influence of environmental descriptors on species occurrence was quantified using a logistic regression model. It was observed that the water velocity was the main limiting factor to occurrence of Serrapinnus notomelas, Hemigrammus marginatus and Moenkhausia sanctaefilomenae while stream depth was the main determinant of Bryconamericus stramineus occurrence. Thus, the first three species are found mainly in sites with less water velocity, while B. stramineus is found mainly in sites with less depth and higher water velocity, suggesting that physiographic habitat characteristics can be important determinants of species colonization and persistence.