Soil impacts of the epigeic earthworm Dendrobaena octaedra on organic matter and microbial activity in lodgepole pine forest
1997
McLean, Anna | Parkinson, D.
The effects of the invasion of the epigeic earthworm Dendrobaena octaedra (Savigny) on soil structure, organic matter, total N and C, and microbial activity were studied over 2 years in a Pinus contorta Dougl. ex Loud. var. latifolia Engelm. forest. During the experiment gradients of earthworm abundance (0 to 3349 m-2) and biomass (0 to 40 g dry wt. m-2) were observed. Organic matter content, total nitrogen, carbon, basal respiration (per gram soil and per gram organic matter), and metabolic quotient (qCO2) decreased with increasing worm biomass, suggesting that D. octaedra is reducing nutrient availability for the microbes, and that microbial efficiency of carbon use is increasing. We suggest that nutrient availability for microbes was reduced through earthworm stimulation of microbial decomposition of organic matter, direct consumption of organic matter by worms (not measured), and stabilization of carbon through binding to clays in casts (not measured). After 2 years pine needle litter decomposition was significantly higher in the two plots with the highest worm biomass than in the two plots with the lowest worm biomass.
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