Potential for nonnative endozoochorous seed dispersal by white-tailed deer in a southeastern maritime forest.
Nonnative invasive plants (NNIP) have far-reaching effects on native ecosystems worldwide. Understanding the role of generalist seed dispersers in spreading NNIP across the landscape is important to the conservation of native ecosystems and to the management of NNIP. We studied white-tailed deer (Odocoileus virginianus) as a seed disperser in a mixed maritime pine (Pinus spp.) forests on Parris Island, SC, with particular interest in the dispersal of Chinese tallowtree [Triadica sebifera (L.) Small], a highly invasive tree species in the southeastern United States, which is a management concern on Parris Island, SC. We collected deer scat pellet groups along transects in two forest types: those that had recently been treated with silvicultural timber harvest (thinned) and those that have not been so treated (unthinned). Using two pellet-treatment methods, directly planting or rinsing and sorting, we determined that, out of 25 species grown under greenhouse conditions, 28% (n=7) were nonnative, small-seeded, herbaceous species. However, T. sebifera was not identified in either of the two treatment methods. Recent forest thinning significantly affected the number of species determined in deer pellet groups (F=8.37; df=1; P<0.01), with more native plant species identified in unthinned (x¯=25±11) than in thinned (x¯=3±10) forest stands (F=5.33; df=1; P=0.02). Our results indicate that white-tailed deer are actively dispersing nonnative seeds but not those of T. sebifera or other woody NNIP.