Abstract

BARRIOS, Margenny  and  RODRIGUEZ, Douglas. Fluvial habitat and their insects as indicators of conservation status in watersheds of Turbio River, Lara State, Venezuela. Bioagro [online]. 2013, vol.25, n.3, pp.151-160. ISSN 1316-3361.

Significant negative impacts in the Turbio River watershed (located in the Andean versant of Orinoco River in Venezuela) require evaluation of the tributaries to achieve adequate management of the hydrobiological resources. During the dry season of 2011, measurements of dimensions, substrate types and coverage, and water quality parameters were taken at sample sites in the upper stream reaches of the drainage of riverbed. At the same time, estimates of the conservation status of the riverine environments were made using an index of fluvial conservation (ICF) and aquatic insects were collected using standard protocol methods. Based on the abundance of families of the insects found, indices were calculated to estimate their variation in richness, dominance and diversity, and water quality status (using biotic indices from BMWP’ and IBF); these were found to be correlated with synthetic variables of fluvial habitat generated using multivariate ordination techniques and the values of the ICF.  The fluvial habitat gradient and the ICF significantly predicted the variation observed in attributes of the insect families, as well as the biotic indices. The great majority of the tributaries of the Turbio River have obvious negative impacts that are reflected in a notable decline of the richness and diversity of aquatic insects.

Keywords : Aquatic insects; hydrographic drainages; biomonitoring; conservation biology.

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