Macroinvertebrate Richness Importance in Coastal Tropical Streams of Esmeraldas (Ecuador) and Its Use and Implications in Environmental Management Procedures

This study was aimed at determining the performance of some indices and community attributes frequently used to assess river quality and test the role of macroinvertebrate taxa richness as element of bioindication in several coastal tropical streams of western Esmeraldas (Ecuador). In addition, a macroinvertebrate taxon list of this region was provided for the first time. Thirteen sampled points distributed across nine streams were selected for this study and nineteen parameters and attributes of bioindication were tested. The differences between nonimpact and impact places were evaluated mainly using one-way analysis of variance. Jackknife 2 and Clench were used to estimate the regional richness and the quality of the inventory, respectively. Seventy taxa (principally genus and family) of the main groups of macroinvertebrates were collected. Measured richness and family richness were the best metric followed by Biological Monitoring Working Party/Colombia (BMWP/Col), Odonata richness, Shannon-Weiner, and EPT richness (Ephemeroptera？+？Plecoptera？+？Trichoptera) indices. Only a slight right trend (Ephemeroptera, Trichoptera, and Chironomidae attributes) or incorrect performances (Average Score Per Taxon (ASPT) and % EPT) were showed by frequently used metrics. Finally, several recommendations were made about taxonomic level used, the ranks of quality of taxa richness, and the effort-results relationship in the field of bioindication. 1. Introduction Global change, population growth, and industrial development are currently exerting great impacts on natural ecosystems, especially on aquatic systems [1]. Agricultural practices, livestock and domestic discharges, the felling of trees, exotic species introductions, and direct erosion have caused increase in the organic matter and suspended solids in water, resulting in strong alterations in the ecological functioning of aquatic systems [2]. Coastal river basins are among the most dynamic aquatic ecosystems on earth, with enormous spatial and temporal complexity, but they are often influenced by continental run-off waters which are rich in nutrients derived from urban, agricultural, and industrial activity [3]. The causes and effects of pollution in tropical rivers have been studied by several researchers, mainly with respect to particulate and suspended matter, the chemical dynamics in waters connected with organic matter content, nutrient loading, and pH [4]. In Latin America, such rivers pass through a strong water quality degradation gradient due to increasing exploitation of the resources and the