Distribution of aquatic invertebrates within a dense bed of Eurasian milfoil (Myriophyllum spicatum L)

Macrophyte associated invertebrates were collected from horizontal and vertical aspects of a dense bed of Myriophyllum spicatum L. over a three year period at Fish Lake, Wisconsin, USA. There were statistically significant differences in the spatial distribution of invertebrates throughout the milfoil bed. Higher invertebrate biomass, density, and taxa richness were observed for the upper foliated sections of plant versus the lower unfoliated sections. The edges of the milfoil bed (either shallow or pelagic or both) contained higher biomass, density, and taxa richness than the center of the bed. Temporal trends were less distinct, although there were fewer significant invertebrate patterns in May than in July or September. We hypothesize this was due to the immature development of the macrophyte bed (and therefore the invertebrate community) at that time of year.