Soil Biology and Land Management.

Land use change and agricultural intensification around the globe have resulted in widespread soil degradation and a loss of ecosystem services and biodiversity.  In many ecosystems, soil macrofauna represent a fundamental component of soil biodiversity due to their impacts on a range of soil processes and their high sensitivity to environmental perturbations.  This talk examines the impact of land use and soil management practices on macrofauna communities across a diverse range of agricultural landscapes in the Americas and then explores the influence of key taxa (mainly earthworms) on a suite of soil-based ecosystem services.  Findings to date suggest that soil disturbance (e.g., burning, tillage, soil compaction) can have strong negative impacts on macrofauna abundance and diversity, while enhanced organic residue inputs (from plant litter, manure, etc.) may help to counteract these effects, at least for some taxa.  Overall diversity of soil macrofauna communities appears to increase with higher vegetation diversity, the maintenance of a mulch layer, and infrequent disturbance.  These findings also suggest that soil macrofauna are highly interrelated with soil physiochemical properties and ground vegetation, such that changes in management for any one of these ecosystem components will likely have unintended cascading impacts on the other soil factors.  When examining the influence of macrofauna on soil properties, various results suggests that active macrofauna communities, earthworms in particular, can provide a number of potential benefits for enhancing water and nutrient use efficiency in agroecosystems, and for supporting the the long-term productivity of soils, but some tradeoffs do exist.  In conclusion, this research suggests that efforts to improve soil management need to consider impacts on soil macrofauna communities and explore ways to best leverage this resource for contributing to overall ecosystem function and sustainability.