Influence of organic matter on invertebrate colonization of sand substrata in a northern Michigan stream

Abstract

AbstractSand is a common substratum in many streams, especially in lacustrine geologies, but has been less studied as a habitat for invertebrates than other substrata such as gravel and cobble. We hypothesized that benthic organic matter (BOM) content would influence the abundance and community structure of macroinvertebrates in sand habitats. Levels of coarse BOM (no = 0, low = 1%, high = 5% organic matter, as dry mass) were manipulated in 45 colonization chambers (volume = 539 cm3) implanted in a sand-dominated reach of Shane Creek in the Ottawa National Forest, Michigan. Chironomidae, Tipulidae, and Trichoptera were common colonizers of chambers. At the end of the 32-d experiment, invertebrate abundance (F2,12 = 7.5, p = 0.015) and biomass (F2,12 = 8.7, p = 0.010) were significantly higher in chambers with low BOM than with no BOM, but the high-BOM treatment did not differ from the no-BOM treatment. Throughout the experiment, functional feeding groups (FFG) were dominated numerically by gathering colle...