Invertebrates in canopy and ground organic matter in a neotropical montane forest, Costa Rica

In a neotropical cloud forest of Costa Rica, we compared the density and composition of macro- and mesoinvertebrates in organic matter found within the canopy to that found in the upper soil horizons on the forest floor. We used a Winkler sifting apparatus to extract invertebrates from accumulated litter and humus. The numerically dominant invertebrate groups in both canopy humus and forest floor leaf litter were mites, adult beetles, holometabolous insect larvae, ants, collembola, amphipods, and isopods. Relative abundances of these major taxa were the same in canopy and on the forest floor, indicating that canopy organic matter shares a fundamentally similar invertebrate community with forest floor. All of these groups except ants had significantly higher densities in the canopy, with a mean density 2.6 times greater on the ground than in the canopy. Ant density was similar in both microhabitats.