Development and validation of a Biotic Index for evaluation of environmental quality in the central region of Argentina

Abstract

The Suquı´a River (Co´rdoba, Argentina) has become an important issue because it flows into Mar Chiquita Lake, one of the largest saline lakes in the world. This water body, together with the expansive swamps of the Dulce River on the northern shore and the mouth of Suquı´a and Xanaes River, is considered one of the most important wetlands in Argentina in terms of biodiversity in a range of freshwater to very saline environments. Nevertheless, the presence of densely populated urban settlements and the increasing environmental impact due to anthropogenic activities characterize the central and lower sections of Suquı´a River Basin. Fishes are particularly affected and change their distribution and abundance as a consequence of the environmental deterioration. We collected information on fish fauna to develop and validate a Biotic Index to assess degradation of the Suquı´a River Basin. We classified fish species according to their sensitiveness or tolerance to environmental degradation, based on their distribution and abundance variations along a water quality gradient in order to design a Biotic Index for Suquı´a River Basin. The set of metrics used in the Biotic Index calculation was conformed by: the abundance of Astyanax eigenmanniorum, Rineloricaria catamarcensis, Gambusia affinis and Cnesterodon decemmacultus, the proportion of sensitive species richness, and the proportion of tolerant species richness. They clearly distinguished between the impaired and referenced sites. We demonstrated that it is possible to use fish as indicators of water quality in Co´rdoba Province (central part of Argentina) in order to carry out rapid and relatively inexpensive monitoring and conservation programs. The application of this Biotic Index showed that fish assemblages reflect the watershed conditions and are sensitive to changes in water quality across the environmental gradient.

Composición y estructura de la ictiofauna del Río Ceballos-Saldán (Córdoba, Argentina)

“…Los orilleros C. decemmaculatus y G. affinis han sido considerados como especies indicadoras de alteración ambiental, ya que aumentan su abundancia en sitios degradados (HUED, 2005). Estos Cyprinodontiformes son más tolerantes y permanecen en áreas degradadas mucho tiempo después de que el resto de los peces haya desaparecido (ARAÚJO, 1998).…”

“…Estudios realizados sobre la calidad del río Suquía PESCE & WUNDERLIN, 2000;HUED, 2005) ponen de manifiesto la necesidad de diagnosticar la situación de los cursos de agua que atraviesan ciudades, a fin de aplicar pautas de manejo adecuadas para prevenir el deterioro de los mismos. Por este motivo, es necesario conocer en detalle la composición y funcionamiento de las comunidades biológicas inmersas en el sistema.…”

Integrity of fluvial fish communities is subject to environmental gradients in mountain streams, Sierra de Aroa, north Caribbean coast, Venezuela

“…invertivorous) and with requirements for a clean substrate for feeding or reproduction. A species could be considered intolerant if its abundance or distribution has been drastically reduced or if it is restricted to high quality habitat sites (Hued & Bistoni, 2005). 4.…”

“…The IBI considers variation in attributes of fish communities in rivers with different degrees of perturbation relative to a regional baseline or reference system with minimal exposure to anthropogenic perturbations. This model was originally developed in the midwestern United States and has been tested successfully in different regions and ecological situations, for example in Africa (Toham & Teugels, 1999), Mexico (Lyons et al, 2000), Belgium (Belpaire et al, 2000) and Argentina (Hued & Bistoni, 2005). Other methods, such as multivariate or multidimensional analysis, explain how variation in species assemblages are associated with environmental gradients (Bond & Lake, 2003;Gerhard et al, 2004), and how these relate to the conservation status or integrity of hydrosystems.…”

The fish community as an indicator of biotic integrity of the streams in the Sinos River basin, Brazil

“…The IBI was designed to evaluate the integrity of the fish community of small streams from the temperate climate in the Midwest region of United States. Later it was adapted to the local conditions of many other countries, as for example France (Oberdorff and Porcher, 1994), Lithuania (Kesminas and Virbickas, 2000), Africa (Hocutt et al, 1994;Toham and Teugel,s 1999), New Zealand (Joy and Death, 2004) and Argentina (Hued and Bistoni, 2005). In Brazil, most IBI studies have been carried out in the states of São Paulo and Rio de Janeiro.…”