Elf Ecological Monitoring In Michigan .3. Earthworm Community Parameters During Pre-Operational Years

A previous description of the lumbricid communities of the Test and Control sites of Project ELF is revised and updated, based on 5 full-season years of sampling. These 5 years (1984 - 1988) encompass the pre-operational period of the U.S. Navy's ELF antenna in Michigan, and resulting data represent a partial foundation for future conclusions regarding potential effects of ELF electromagnetic fields. Of a total of eight species, seven are now known to be common to both sites, only A. longa remaining unique to the Test community. Annual fluctuations in species dominance, diversity and equitability are shown to be appreciable. Potential sources of error in the derivation of community indices, due either to sampling technique or to problems in immature identification, are listed. Variations in community structure due to the relative contribution of species with different life styles are discussed, using vertical distribution, habits and population structure as criteria. Year-to-year variations in these parameters are presented. Analysis of horizontal distribution of species is used as indicator of the homogeneity of each study site.