The Use of Artificial Leaf Packs
to Survey Stream Macroinvertebrates

Nathan J. Winkler
School of Science and Natural Resources
Lake Superior State University
Sault Ste. Marie, Michigan 49783 USA

October 29, 1996

Abstract:	Artificial leaf packs are sampling apparatus used in streams. Leaf packs
mimic the autumnal leaf-litter accumulation in woodland streams. This accumulation
of leaves serves as both a food base and home for macroinvertebrates.  The
objectives of this study were to 1) to determine what types of macroinvertebrates would
colonize artificial leaf packs and 2) to determine if the substrate composition at the
sample site had any bearing on the macroinvertebrates present in the leaf packs. In
July of 1996, artificial leaf packs were constructed and placed into a first order stream
in northwest lower Michigan. After three weeks of immersion, leaf packs were pulled
and the contents analyzed.  Macroinvertebrates present in the leaf packs included
representatives from the taxa Plecoptera, Trichoptera, Diptera, Ephemeroptera,
Isopoda and Arthropoda. Dominant substrate compositions were then determined for
sample sites. They were sand and gravel. Sample sites were divided under these two
substrate types and relative abundance of taxa was calculated. A Model I ANOVA
statistical test was used to determine if there was any difference in the relative
abundance between sand and gravel. At the 95% confidence level, it was found that
there was no difference between the means. The results of the ANOVA test lead to the
conclusion that the colonization of leaf packs was a function of the microhabitat
created by the leaf pack and not a function of the substrate composition of the site.

Selected References

Hynes, H.B.N. 1970. The Ecology of Running Waters. Liverpool University Press.
Liverpool, Ireland: pp.193,411.

Merritt, R. and Cummins, k. 1996. An Introduction to the Aquatic Insects of North
America. Kendall/Hunt Publishing Co. Dubuque, IA: pp. 26, Figure 3.25.