Distribution, habitat and conservation status of two threatened annual fishes (Rivulidae) from southern Brazil

Abstract

This study presents information on the distribution of Austrolebias cyaneus and A. juan- langi, 2 annual fish species of southern Brazil considered threatened. Furthermore, data are provided on the conservation status of these species and their habitat characteristics to assist in the develop- ment of management plans and in the selection of priority areas for conservation of annual fishes in southern Brazil. A total of 6 populations of A. cyaneus and 3 populations of A. juanlangi were sam- pled from small ponds less than 1000 m 2 in surface area. We sampled 104 specimens of A. cyaneus, distributed in the municipality of Rio Pardo and Minas do Leao in the basins of the Francisquinho, Capivari, and Dom Marcos streams, Jacui River basin. A. juanlangi was recorded in the municipali- ties of Herval, Hulha Negra, and Pedras Altas, Jaguarao River basin, with 53 specimens being cap- tured. At the sampling sites, the main threat to both species was rice cultivation. All pools were altered, isolated, and in an advanced state of degradation as a result of this monoculture. The restricted distribution area of the annual fishes and the advanced state of degradation and habitat loss of the wetlands sampled in this study justify the creation of conservation units in the areas of occurrence of Rivulidae species.