wave towards a new steady state: effects of earthworm invasion on soil microbial functions

• Published in: Biological invasions Vol. 13; no. 10; pp. 2191 - 2196
• Main Authors: Eisenhauer, Nico, Schlaghamerský, Jiří, Reich, Peter B, Frelich, Lee E
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer-Verlag 01.10.2011; Springer Netherlands; Springer Nature B.V
• Subjects: Animal populations; Biomass; Biomedical and Life Sciences; Developmental Biology; disturbed soils; earthworms; Ecological effects; Ecological function; ecological invasion; Ecology; Ecosystems; forest ecosystems; Forest soils; Forests; Freshwater & Marine Ecology; hardwood forests; Hardwoods; Invasion Note; invasions; invasive species; Life Sciences; Microbial activity; microbial biomass; Nonnative species; Plant Sciences; Respiration; Soil; soil ecology; Soil microorganisms; Soils; Terrestrial ecosystems; Water stress; Waves; Worms; North America; Ecosystem change; Microbial biomass; Northern hardwood forests; Microbial respiration; Exotic earthworms; Forest floor
• ISSN: 1387-3547; 1573-1464
• DOI: 10.1007/s10530-011-0053-4

Earthworms are ecosystem engineers that cause a long cascade of ecological effects when they invade previously earthworm-free forests. However, the consequences of earthworm invasion for soil microbial functions are poorly understood. Here, we used two well-studied invasion fronts of European earthworms in northern North American hardwood forests previously devoid of earthworms in order to investigate three stages of earthworm invasion: uninvaded, the front of the leading edge of earthworm invasion and locations invaded at least 10 years previously. Soil microbial biomass, respiration and metabolic quotient were measured. Earthworms had marked effects on soil microbial biomass (−42%) and respiration (−32%). At both sites, impacts were most pronounced at the leading edge of the invasion front, significantly decreasing soil microbial C use efficiency. This was most likely due to the disturbance of the soil microbial community caused by water stress. Based on these results, we hypothesize that effects of earthworm invasion on native soil ecosystem functioning are most pronounced at the peak of the invasion wave. After experiencing this wave, ecosystems possibly enter a new steady state with altered biotic compositions and functions.