Effects of the Exotic Invasive Shrub Lonicera maackii on the Survival and Fecundity of Three Species of Native Annuals

Abstract

Abstract Negative effects on native plant populations are often attributed to invasions by exotic plants, but experimental evidence is lacking to support many of these claims. Lonicera maackii, an exotic shrub with long leaf phenology, has become naturalized throughout the eastern United States. This study investigated the effects of L. maackii on demography of Galium aparine, Impatiens pallida and Pilea pumila, native annual herbs in differing phenological categories. These interactions were examined in two Ohio forest stands. One stand has a history of logging, burning and grazing and a higher L. maackii density, whereas the other stand has little anthropogenic disturbance and a lower L. maackii density. Three types of experimental plots were established: L. maackii removal, L. maackii present and, at the less disturbed stand, L. maackii absent. Seedlings of the annuals were transplanted and monitored for 1 y for survival to reproductive age and fecundity. In the more disturbed stand, survival of Galium...