Earthworms, arthropods and plant litter decomposition in aspen (Populus tremuloides) and lodgepole pine (Pinus contorta) forests in Colorado, USAThe 7th international symposium on earthworm ecology · Cardiff · Wales · 2002

Abstract

Summary We compared the abundance and community composition of earthworms, soil macroarthropods, and litter microarthropods to test faunal effects on plant litter decomposition rates in two forests in the subalpine in Colorado, USA. Litterbags containing recently senesced litter of Populus tremuloides (aspen) and Pinus contorta (lodgepole pine) were placed in aspen and pine forests to monitor their decay rates and quantify litter microarthropod abundance. Earthworms and macroarthropods were collected by hand from the soil. Three species of earthworms were found in the aspen forest: Octolasion cyaneum , an anecic worm; Dendrobaena octaedra , an epigeic worm and Aporrectodea trapezoides , an endogeic worm. We found a higher density and fresh biomass of earthworms in the aspen (40 worms m –2 and 4.4 g m –2 ) than in the pine forest (0.8 worms m –2 and 0.6 g m –2 ). The lodgepole pine contained only earthworm species, D. octaedra . Macroarthropod density did not differ between the forests. Total density of microarthropods in the aspen and lodgepole pine forests was 6.40 and 5.24 individuals g –1 of dry litter, respectively and did not significantly differ between forests. The percent of mass remaining was different between litter species (r 2 = 0.73, P