Epiphytic macroinvertebrates along a gradient of Eurasian watermilfoil cover

摘要

The exotic macrophyte Eurasian watermilfoil (Myriophyllum spicatum L.) has spread throughout North America and has come to dominate macrophyte communities in many North temperate lakes. Because of the central role that macrophytes play in littoral zone foodweb interactions, the spread of this nuisance species and subsequent macrophyte management actions could potentially alter many foodweb interactions. In particular, Eurasian watermilfoil's morphology and its dense canopies may influence the macroinvertebrate communities associated with macrophytes. In this study, we examined how Eurasian watermilfoil cover affects epiphytic macroinvertebrate biomass in six southern Michigan lakes that range from 20 to 95 percent cover of Eurasian watermilfoil. The Eurasian watermilfoil gradient was created by treating three lakes with 5 ppb fluridone (Sonar~(R)) in May 1997. We quantified epiphytic macroinvertebrate biomass and macrophyte cover in July and August 1999. Our results show that macroinvertebrate biomass on the dominant plant species in a lake may decrease as percent Eurasian watermilfoil cover increases in lakes. In addition, we did not detect negative effects of the use of fluridone on macroinvertebrate biomass two years post-treatment.