A SURVEY OF NATIVE AND INVASIVE GENOTYPES OF PHRAGMITESAUSTRALIS ALONG MICHIGAN'S WEST COAST

摘要

In North America, Phragmites australis (common reed) consists of a native North American group with several genetic forms and a highly invasive group with a single genetic form. Little is known about the environmental factors that affect the relative distribution of native and invasive populations, and it is often difficult to differentiate between the two groups based on physical characteristics alone. The western Lower Peninsula of Michigan provides an excellent opportunity to evaluate the relationship between environmental gradients and the spread of Phragmites. The Lake Michigan coast presents a strong temperature gradient from the north to the south, whereas a moisture gradient is found from west to east from the Lake Michigan shoreline inland. The goal of this study is to assess the risk of invasion by the invasive genotype by: 1) determining the genotypes of individuals in Phragmites australis populations in western Michigan; and 2) evaluating the geographic distribution of the representative genotypes throughout the region. Examination of 58 samples of Phragmites australis using chloroplast gene markers from throughout western Lower Peninsula of Michigan yielded only the invasive genotype in the southern regions and a mixture of native, invasive, and Gulf Coast genotypes in the northern regions. Only one of the populations examined contained individuals of both native and invasive genotypes. No trends were observed along the east-west gradient.