Peces y ambientes en la Argentina continental

Abstract

This monograph is about the freshwater fish communities of Argentina, and their composition and changes in the geographic space. The most important trait is the ecological change observed along a NE - 8W axis. The northeastern fish fauna occupies a fanlike area, from the Paraguay and Paraná Rivers to the eastern border of the Andes to the west and to the Pampasic Highlands in central Argentina. In northwestern and central Argentina there are numerous endorheic basins, but they do not have a long enough history to have very different fish species or flocks. Along an east - west gradient, basins connected with the Paraguay and Paraná Rivers show regular variations in the number of species, in diversity, and in the organisation of fish communities. In the pampasic plain, south of the Paraná River Delta, the commonest aquatic environments are the "lagunas", which show the influence of the subtropical area. The fish fauna from the lagunas shows a clear impoverishment to the southwest, significantly correlated with temperature. A western stripe north of 36°8 along the Andes, and parts of central Argentina, have an impoverished and transitional fauna with some endemics. The Patagonian fish fauna, living mainly south of the Colorado River, is scarce in number of species and phylogenetically different from the resto Based mainly on these faunistic units, we describe the composition of the fish fauna in each of them, the ecological traits of their fishes, the limnological characteristics of the environments, the structure of communities, relevant adaptations and peculiarities of fishes, and their general relationships with geology, hydrology and climate. Within this ecological framework, the place and function of many species in several environments are discussed. Limnology is treated with some detail, particularly when information is related more or les s directly to the biology of fishes.