A Comparison of Macroinvertebrate and Epiphyte Density and Diversity on Native and Exotic Complex Macrophytes in Three Vermont Lakes

Abstract Invasion of New England lakes by exotic macrophytes can alter trophic interactions if the invaders host macroinvertebrate and epiphyte communities different from those of the native species they replace. Macroinvertebrate density and diversity appears to increase with macrophyte complexity and epiphytic algae colonization, which are also positively correlated. Because of this confounding effect, we investigated native and exotic macrophyte species of similar complexity in order to answer the question: Does the exotic macrophyte Myriophyllum spicatum have lower epiphyte density and richness that results in lower macroinvertebrate density and diversity than those found on a native species of similar complexity? Using independent-sample t-tests, we investigated this question in mixed macrophyte stands of three Vermont lakes. Holding complexity constant, macroinvertebrate density and diversity was positively related with epiphyte density and richness (r 2 = 0.17 and 0.13, respectively). Generally, M....