Abstract

LAFUENTE, Wilson; SOTO, Luz Marina; LOPEZ, Carlos  and  DOMINGUEZ-GRANDA, Luis. Effects of a Crude Oil Spill in the Benthic Macroinvertebrate Community of an Ecuadorian Amazon River. Ciencias Ambientales [online]. 2019, vol.53, n.1, pp.1-22. ISSN 2215-3896.  http://dx.doi.org/10.15359/rca.53-1.1.

Oil spills are a major source of disturbance to benthic macroinvertebrates from inland waters. However, studies regarding these disturbances in tropical regions, and particularly in the Neotropics, are limited. This study evaluates the effects of a 11,700-barrel heavy crude oil spill on the benthic macroinvertebrate community of Santa Rosa, Quijos and Coca rivers, Ecuadorian Amazon. The evaluation used a biotic index and water quality and sediments variables, both in the impacted sites and in the reference sites during two field trips in 2011 and 2012. Spearman correlations established significant negative relationships (p <0.05) between total petroleum hydrocarbons and Ephemeroptera-Plecoptera-Trichoptera (EPT index), Trichoptera, and Elmidae family taxa. An inverse relationship was established between the SIGNAL2 index and total petroleum hydrocarbons. A multiple response permutation procedure (MRPP) determined a difference between the macroinvertebrate communities of reference and the impacted stations in 2011, and between the macroinvertebrate communities of reference stations 2011 and stations impacted in 2012. Non-metric multidimensional scaling involved using three dimensions, in which axis two was better related to total petroleum hydrocarbons (r = 0.45). These results suggest that factors other than total petroleum hydrocarbons are responsible for the heterogeneous composition of the macroinvertebrate communities.

Keywords : biotic indices; ecological recovery; Neotropics.

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