Diversidade da ictiofauna de riachos de cabeceira em paisagens antropizadas na bacia do Alto Paraguai

Abstract

The advance of the agricultural frontier is one of the biggest threats to the communities’ structure of the fi sh assemblages in headwaters streams. The infl uence of land use and occupation on the fi sh assemblages structure in headwater streams was evaluated in three stream reaches in the Upper Paraguay River Basin, state of Mato Grosso, Brazil. Samples were collected from July to December 2013 using dragging net and sieve in Ararão, Queima Pé e Russo streams, municipality of Tangará da Serra. Totals of 35 species encompassing 4, 192 individuals were collected, and the dominant species within were Moenkhausia lopesi (Britski & de Silimon, 2001) e Knodus moenkhausii (Eigenmann & Kennedy, 1903), accounting for 68.5% of the individuals. There were no signifi cant diff erences in richness or abundance among the three streams, but Shannon diversity index was higher in the Russo stream (H’ = 2,33). The high percentage of native vegetation converted into agriculture crops (49.20%) and cattle raising (30.69%), disclosed a strong negative relationship between agriculture and richness, showing that as the agriculture fi elds become smaller the species richness becomes larger.