RELATIONSHIPS BETWEEN SOIL PROPERTIES AND COMMUNITY STRUCTURE OF SOILMACROINVERTEBRATES IN OAK-HICKORY FORESTS ALONG AN ACIDIC DEPOSITION GRADIENT

Soil macroinvertebrate communities were studied in ecologically analog ous oak-hickory forests across a three-state atmospheric pollution gra dient in Illinois, Indiana, and Ohio. The goal was to investigate chan ges in the community structure of soil fauna in study sites receiving different amounts of acidic deposition for several decades and the pos sible relationships between these changes and physico-chemical propert ies of soil. The study revealed significant differences in the numbers of soil animals among the three study sites. The sharply differentiat ed pattern of soil macroinvertebrate fauna seems closely linked to soi l chemistry. Significant correlations of the abundance of soil macroin vertebrates with soil parameters suggest that their populations could have been affected by acidic deposition in the region. Abundance of to tal soil macroinvertebrates decreased with the increased cumulative lo ading of acidic deposition. Among the groups most sensitive to deposit ion were: earthworms, gastropods, dipteran larvae, termites, and preda tory beetles. The results of the study support the hypothesis that chr onic long-term acidic deposition could adversely affect the soil decom poser community which could cause lower organic matter turnover rates leading to an increase in soil organic matter content in high depositi on sites.