Aquatic macroinvertebrate assemblages and ecological state of Dali sub-basin, Risaralda State, Colombia

Abstract

Background. Aquatic macroinvertebrates have been widely used as bioindicators of the response of aquatic ecosystems to human activities that affect them. Thus, their use as bioindicators is included in different protocols for the ecological assessment of streams. Goals. This study assessed the ensemble of aquatic macroinvertebrates in Dali Creek along with its ecological condition. Methods. Six surveys over seven reaches of the Creek were conducted from April 2012 through November 2013. The multihabitat method was used to collect the macroinvertebrates, and a visual assessment was used to study the state of the aquatic habitat and the riparian vegetation. Results. The results show that Aquatic macroinvertebrates are abundant and diverse, particularly at the reference points located upstream on the Dali Creek and its tributary QR2. It was found significant differences between microhabitats sampled composition (K-W p<0.05). The BMWP index displayed a condition of high quality, with ``very clean water to clean'' condition. Similarly, the IHF index showed that all the sampling points present excellent condition except the QR3 point. Finally, the IMEERA index revealed that the ecological status of stream Dali and QR2 tributary is very good to good; while for the sites QR3 the condition is very bad, despite the natural restoration process of the stream channel. Conclusions. The relationships between structural complexity of the physical habitat and the macroinvertebrates diversity are interesting aspects for studying streams in the Colombian Andes.