PARENT SESSION
Oral Session #101: Plant-Animal Interactions.
Presiding: S. Faeth
Friday, August 9. 9:00 AM to 12:00 PM. Coconino Meeting Room, TCC.
Searching for effects of animal dispersal on the distribution of oak seedlings.
Smallwood, Peter*,1, Terzaghi, William2, Carlson, John3, Ward, Jeffery2, Contreras, Tom2, Ribbens, Eric4, Mank, Judith3, Steele, Michael2, 1 University of Richmond, Richmond, Virginia2 Wilkes University, Wilkes-Barre, Pennsylvania3 The Pennsylvania State University, University Park, Pennsylvania4 Western Illinois University, Macomb, Illinois
ABSTRACT- Previous work has shown that animals disperse viable acorns from the red oak species group far more often than those from the white oak group. Assuming animal dispersal is an important factor in determining the distribution of oak seedlings, we predict that seedlings from the red oak group should be widely distributed, with a greater mean dispersal distance from parent trees than for seedlings from the white oak group. We are testing this prediction by i) mapping oak stems in forest study plots (potential parent trees and seedlings), ii) using the RECRUITS algorithm to estimate seed shadow parameters, and iii) using DNA fingerprinting to establish parent-seedling pairs, allowing us to measure dispersal distances directly. We have established four 1.5-ha study plots in three states of the USA (PA, MD, VA). We chose study plots with large numbers of mature trees and seedlings of both red and white oak species. At this writing, we have parent-offspring matches for two of the four study plots. The data do not support our prediction. The average distance between parent trees and their seedlings for white oaks is the same as that for red oaks on these study plots; the ranges are also similar. The results suggest that acorns -especially white oak acorns-- are dispersed further from parent trees than we expected. With our DNA fingerprinting techniques using STR's, we are only able to match ca 12% of the oak seedlings to parent trees. We discuss some of the limitations of our DNA techniques. We will also compare the estimated seed shadow parameters from RECRUITS with those from the DNA fingerprinting study. NSF-DBI #997 8807
KEY WORDS: seed dispsersal, Quercus, oak, RECRUITS