Rapid assessment of river water quality using macroinvertebrates: a family level biotic index for the Patagonic Andean zone

MISERENDINO, M. L; PIZZOLON LINO

ACTA LIMNOLOGICA BRASILIENSIA

Sociedade de Limnologia Brasileira

Lugar: San Pablo; Año: 1999 vol. 11 p. 137 - 148

0102-6712

Rapid assessment of river water quality using macroinvertebrates: a family level biotic index for the patagonic andean zone. The progressive damage produced to the aquatic ecosystems by modern societies makes it necessary to rapidly detect water quality-changes. Macrobenthic organisms have been the most commonly used indicators of running water quality as they present appropriate size, sedentary habits and long-life cycles. The watercourses of Patagonia have also suffered the impact of anthropic activities. The high degree of endemism in several zoobenthic species prevents the use of foreign indexes. Moreover, the status of the knowledge of some taxonomical groups is deficient. There are several groups of macroinvertebrates in Patagonian rivers for which no keys are available at the generic or specific levels. In this study we propose a family-level biotic index, the BMPS (Biotic Monitoring Patagonian Streams) to estimate water quality in rivers. We also compare the performance of the BMPS with a previous tested index: the IAP (Andean Patagonic Index) in an organic polluted system. The BMPS is an adaptation of the BMWP  (Biological Monitoring Working Party). In its construction, different surveys carried out in 43 Patagonian rivers, from 1991 to 1996,  were taken into account. More than 200 macroinvertebrate samples collected were used to obtain biogeographical and ecological information of the species. The BMPS resulted in a table of 95 families with different pollution sensivity grades: 1 to 10.  The BMPS was tested in the Esquel-Percy river system (Chubut, Argentina). The mean annual values of the BMPS were comprised between 7 and 109.4, while the IAP mean values were between 2.5 and 9.75. A cluster among of BMPS, IAP, specific richness and Shannon-Weaver Diversity Index values was obtained. The BMPS, specific richness and the IAP were closely related.  The BMPS was highly correlated with the IAP (r=0.96 n=106, regression multiplicative model) what indicates that the BMPS is a good estimator of the organic pollution levels.  Keywords: Rivers, macroinvertebrates, biotic index, Patagonia