Soil Microarthropod Abundance Following Old‐Field Litter Manipulation

Abstract

A field experiment was set up in an old field in Michigan in spring and summer 1964, to test whether or not litter determines the abundance of soil microarthropods. Treatments were established to distinguished the importance of litter as a nutritional substance from its importance as a moderator of the microclimate or as a refuge for prey organisms. Treatments were: 1) no litter; 2) high litter; and 3) natural litter replaced with dacron polyester fiberfill, a nondecomposing insulative substance. The first fall the abundance and distribution of microarthropods in the dacron treatment were most similar to that in the high—litter treatment, whereas with respect to the amount of decomposable litter present, the dacron treatment was identical to that in the no—litter treatment. At this time the physical factors in the environment were more favorable in the high—litter and dacron treatments than in the no—litter treatment. The following spring, differences in physical factors among treatments were minimal, and there were no detectable effects of treatment on abundance of microarthropods. The following summer there were significant effects of treatment on physical factors, and the dacron treatment was again most similar to the high—litter treatment with respect to the abundance and distribution of microarthropods. The results demonstrated that physical factors in the environment were of major importance in determining the vertical distribution and abundance of soil microarthropods. Evidently, these organisms were not limited by the nutritional properties of the litter, at least over the 14—month period of the study.