Effects of site preparation techniques on communities of soil mites (Acari: Oribatida, Acari: Gamasida) under short-rotation forestry plantings in New York, USA

To address the question of how production of woody biomass crops on retired agricultural land will affect soil biodiversity, we investigated the effects of site preparation techniques associated with production of willow (Salix sp.) on the abundance, species diversity and community structure of two groups of mites (Oribatida and Gamasida). The effects of tillage, herbicide application, cover crop and mode of planting were evaluated in a 4 year-long replicated field experiment. Twenty-eight species of Oribatida and 35 species of Gamasida were represented in willow plantings. The predaceous Gamasida had more pronounced changes in abundance and diversity in response to the site preparation treatments than saprophagous and mycophagous Oribatida. Results indicated that (1) soil cultivation had negative effects on the abundance and diversity of soil mites during the first year of the experiment, later superceded by other factors; (2) the use or lack of tillage contributed to differences in mite community structure; and (3) following the initial disturbances, the abundance and diversity of soil mites increased in all treatments up to the end of the experiment. The success or failure of the willow crop and the changes in soil environments created by the different plant communities could explain the differences in soil mite populations among treatments best, especially 2 and 3 years after the beginning of the experiment.