The Rapid Growth of a Population of Reed Canarygrass (Phalaris arundinacea L.) and Its Impact on Some Riverbottom Herbs

BARNES, W.J. (Biology Department, University of Wisconsin-Eau Claire, Eau Claire, WI 54702). The rapid growth of a population of reed canarygrass (Phalaris arundinacea L.) and its impact on some riverbottom herbs. J. Torrey Bot. Soc. 126:133-138. 1999.-The rapid expansion of a population of reed canarygrass on a small river island in western Wisconsin was documented for a 15 year period. Transect samples conducted in 1981 disclosed a single small population. Subsequent transect samples in 1996 revealed that reed canarygrass had become the dominant plant at elevations of 1 m elevation, were not adversely affected by the increase in reed canarygrass. However, several formerly abundant herbs and grasses of low areas have been displaced and are now infrequent. Some reasons for the increase in reed canarygrass appear to include a more aggressive introduced strain of this grass and current low summer flows that have made more areas of <1 m available for longer periods of time during the growing season.