PARENT SESSION

ASSESSING THE INFLUENCE OF SMALL MAMMALS ON OAK REGENERATION: SEED DISPERSAL VS. SEEDLING ESTABLISHMENT. Michael A. Steele¹, Amy McEuen¹, John Carlson², Thomas Contreras^1,3, Peter D. Smallwood⁴ and William Terzaghi¹. ¹ Department of Biology, Wilkes University, Wilkes-Barre, PA, USA; ² School of Forest Resources and the Huck Institute for Life Sciences, Pennsylvania State University, University Park, PA, USA; ³ Department of Wildlife Ecology & Conservation, University of Florida, Gainesville, FLA, USA; ⁴ Department of Biology, University of Richmond, Richmond, VA, USA.

ABSTRACT- To fully understand the impact of small mammals on plant regeneration it is necessary to decipher patterns of both seed dispersal and seedling establishment. To do this we measured seed and seedling shadows of Quercus rubra and Quercus alba in oak forests of Pennsylvania where the primary mammalian dispersal agents include Sciurus carolinensis as well as two species of Peromyscus and Tamias striatus. Seed dispersal was estimated by following the fates of 9000 metal-tagged acorns/year over four years at three sites. Seedling dispersal was estimated through DNA fingerprinting using ten primer pairs that amplify polymorphic STRs and then identifying the closest potential parent to each seedling based on individual fingerprints (n = 260 seedlings and 105 parents). Preliminary results suggest direct measures of seed dispersal using metal-tagged acorns give shorter mean dispersal distances (10m) than DNA parent-seedling estimates (30m), and that Q. alba acorns are moved considerably farther than predicted from any studies on seed dispersal. These results suggest that methodological limitations in measuring seed dispersal may underestimate dispersal distances, and that rare long distance dispersal events, followed by high seedling mortality at shorter distances, may contribute to patterns of oak regeneration.

KEY WORDS: seed dispersal, scatterhoarding, Quercus, oak regeneration