Interactions Underground: Soil biodiversity, mutualism, and ecosystem processes

Extract

Soil biodiversity has received considerable attention recently because of greater recognition that soil species and their interactions can influence a number of ecosystem processes (e.g., decomposition, net primary production, and trace gas production; Setälä and Huhta 1991, Freckman et al. 1997, Naeem and Li 1997, Groffman and Bohlen 1999). Recent scientific research on soil biodiversity is increasing our baseline knowledge of the species richness (Lawton et al. 1996) and global distribution (Brussaard et al. 1997, Wall and Virginia in press) of soil organisms and of their economic value to ecosystems (Pimentel et al. 1997, Vitousek et al. 1997). This research has also identified gaps in our knowledge, such as the nature and extent of the linkages among belowground systems (i.e., soils, freshwater sediments, and marine sediments; Freckman et al. 1997, Wagener et al. 1998).

These increasingly interdisciplinary studies are focused on the species that are critical for the maintenance of ecosystem processes. The information from such studies will contribute to future management of soils and ecosystems under scenarios of increasing human-derived physical, chemical, and biotic disturbances (e.g., plowing, pollution, elevated CO₂, and invasive species; Vitousek et al. 1997, Jones et al. 1998). The elucidation of soil biotic interactions, in particular mutualistic interactions, which we highlight in this article, offers additional evidence for the importance of soil biodiversity at the species and functional levels in the maintenance of ecosystem processes.