PARENT SESSION
Poster Session #2: Plant-Animal Interactions.
Monday, August 6, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall

A multidisciplinary approach to understanding the dispersal syndrome of Oaks (Quercus L.): linking behavior of dispersers with seedling establishment and forest structure.

STEELE, MICHAEL¹, SMALLWOOD, PETER², TERZAGHI, WILLIAM¹, CARLSON, JOHN³, LUCENT, DEL¹, WARD, JEFF¹, CONTRERAS, THOMAS¹, ^{1 2 3}

ABSTRACT- The link between the dispersal of seeds and the recruitment of seedlings depends on an understanding of the behavior of seed dispersers and the dispersal syndromes of the plants they disperse. For Oaks (Quercus L.), differences in seed and seedling characteristics between the Red (RO) and White Oak (WO) groups can affect seed dispersal/seedling establishment and the resulting distribution and age structure of oak stands. Observations from this ongoing study support the hypothesis that differences between RO and WO acorns/seedlings result in: 1) differential dispersal by small mammals and 2) RO acorns being dispersed greater distances from parental sources with significant differences in seedling distributions between the groups. Results using tagged acorns and analytical models incorporating location data for seedlings and mature oaks (RECRUITS), suggest that WO acorns have lower mean dispersal distances and greater predation rates than that of RO acorns (p < 0.05). However, for seedlings, results of DNA fingerprinting analysis suggest that seedling shadows for both groups may extend further than previously thought. Moreover, RO and WO seedling physiology indicate differences in photosynthetic characteristics between the groups (p < 0.05) with WO seedlings exhibiting greater shade tolerance. Our results suggest differential dispersal of oak species based on seed characteristics and differences in seedling physiology that may follow from these dispersal patterns. These patterns may have a significant impact on forest structure.

KEY WORDS: seed dispersal syndrome, Quercus L., seedling physiology, disperser behavior