Elevated CO₂ and O_3t concentrations differentially affect selected groups of the fauna in temperate forest soils

Abstract

Rising atmospheric CO₂ concentrations may change soil fauna abundance. How increase of tropospheric ozone (O_3t) concentration will modify these responses is still unknown. We have assessed independent and interactive effects of elevated [CO₂] and [O_3t] on selected groups of soil fauna. The experimental design is a factorial arrangement of elevated [CO₂] and [O_3t] treatments, applied using Free-Air CO₂ Enrichment technology to 30 m diameter rings, with all treatments replicated three times. Within each ring, three communities were established consisting of: (1) trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera) (2) trembling aspen and sugar maple (Acer saccharum) and (3) trembling aspen. After 4 yr of stand development, soil fauna were extracted in each ring. Compared to the control, abundance of total soil fauna, Collembola and Acari decreased significantly under elevated [CO₂] (-69, -79 and -70%, respectively). Abundance of Acari decreased significantly under elevated [O_3t] (-47%). Soil fauna abundance was similar to the control under the combination of elevated [CO₂ + O_3t]. The individual negative effects of elevated [CO₂] and elevated [O_3t] are negated upon exposure to both gases. We conclude that soil fauna communities will change under elevated [CO₂] and elevated [O_3t] in ways that cannot be predicted or explained from the exposure of ecosystems to each gas individually.

Citation

Loranger, Gladys I.; Pregitzer, Kurt S.; King, John S. 2004. Elevated CO₂ and O_3t concentrations differentially affect selected groups of the fauna in temperate forest soils. Soil Biology & Biochemistry. 36: 1521-1524.