GROWTH AND REPRODUCTION OF THE INVASIVE LIGUSTRUM SINENSE AND NATIVE FORESTIERA LIGUSTRINA (OLEACEAE): IMPLICATIONS FOR THE INVASION AND PERSISTENCE OF A NONNATIVE SHRUB.

Ligustrum sinense (Oleaceae) is an invasive shrub in the southeastern United States that was introduced from China. In middle Tennessee, the species grows with Forestiera ligustrina (Oleaceae), a shrub native to the southeastern United States, in the redcedar and/or hardwood forests surrounding cedar (limestone) glades. Here we compare the growth and reproduction of the two species and identify attributes that might influence the invasiveness and persistence of L. sinense. Plants of both species were sampled along the woodland edges of cedar glades and in the (primarily) redcedar forest at Stones River National Battlefield, Rutherford County, Tennessee, between March 2000 and February 2001. MANOVAs (P ≤ 0.05) indicated significant differences between species and habitats for several of the 23 traits measured in the study. Regardless of the habitat, L. sinense had a more treelike growth form—higher leaf area ratio (leafiness), leaf mass ratio (investment in leaf biomass), stem elongation rate, and number of fruits per ramet—and a lower percentage of insect-damaged leaves and leaf abscission rate than F. ligustrina. Height and leaf areas of L. sinense plants growing in the woods were greater than those of L. sinense plants growing along the glade and greater than those of F. ligustrina plants growing in both habitats. Branch architecture did not differ appreciably between the species. Ligustrum sinense appears to possess a competitive advantage over F. ligustrina because of its greater ability to spatially and temporally capture light, a phenomenon that may lead to higher photosynthetic capacity and resource-use efficiency, and because of the higher fruit production we observed. [ABSTRACT FROM AUTHOR]