Colonization by aquatic macroinvertebrates on two substrates in a stream of the Sierra Nevada de Santa Marta, Colombia

Abstract

The aquatic macroinvertebrates that inhabit lotic ecosystems are ecologically important because they are the most abundant and diverse of these systems; however, ecological processes such as the colonization they conduct have been poorly studied in the Neotropical region. The aim of this work was to study the colonization process by aquatic macroinvertebrates on natural and artificial substrates during periods of drought and rain in the middle part of the Gaira River (Sierra Nevada de Santa Marta). Ce-ramic plates were installed as artificial substrate and stones as natural substrate, theses were exposed for one, two, eight, 16, 24, 32 and 41 days to natural colonization by aquatic macroinvertebrates. The differences between substrates and between seasons were evaluated according to the density, abun-dance, and richness of invertebrates. During the colonization processes, no significant differences between substrates were detected in the structure of the macroinvertebrate communities (ANOSIM, P > 0.05, R = 0.015) but between climatic seasons (ANOSIM, P < 0.05, R = 0.267). The greatest abundance and richness occurred during the drought period. The most abundant taxa were the genera Simulium, Heterelmis, Baetodes, Anacroneuria, Leptohyphes, and the Orthocladiinae subfamily. The richness of genera was higher in the rainy season for natural substrates (49 taxa). This study showed that the flow is a key factor that moderates the colonization processes and the structure of the communities of aquatic macroinvertebrates on natural and artificial substrates in the middle part of a Neotropical river.