The effect of substrate texture on colonization by stream macroinvertebrates

Museo Nacional de Ciencias Naturales (CSIC). José Gutiérrez Abascal 2, 28006. Madrid, Spain. Current address: School of Tropical Biology, James Cook University, Townsville, Qld 4811, Australia.

Corresponding author: luz.boyero@jcu.edu.au

Abstract

The effect of substrate texture on colonization by stream macroinvertebrates was studied in a mountain stream. Experimental patches made of natural substrate, with two levels of cobble and gravel texture (rough and smooth), were subjected to two colonization periods (two hours and one week) within a riffle. Cobble texture affected the number of individuals and taxa colonizing substrate patches, although these relationships depended on time of colonization and some local environmental factors. Texture influence was different for different taxa, and only affected the scraper functional feeding group after one week of colonization, probably in relation to the development of an epilithic layer. These results suggest a significant effect of the surface texture of substrate on colonization by macroinvertebrates, although the effect is complex and needs more careful examination.