Spatial and temporal patterns of seed predation on three tree species in an oak-pine forest

We experimentally examined spatial and temporal patterns of seed predation on three tree species in an oak-pine forest in southern Maine, USA. Rodents were the principal seed predators. Rates of seed loss varied with tree spe cies and exposure to three different suites of potential seed predators tal l vertebrate seed predators, medium-sized rodents [primarily squirrels] and small rodents [primarily mice and voles]). Acer rubrum seeds were removed more slowly (mean of 17.7% within 2 d across all habitats and treatments in 1991) than seeds of either Qurecus rubra or Pinus strobus (e.g., > 99% rem oved within 2 d across all habitats and treatments for each species in 1991 ). Levels of final removal (cumulative removal at final census) varied with year but not with microhabitat; i.e., seed predation in four types of Fore st yap was not significantly different than in intact forest. Both field da ta and experimental feeding trials with captive Peromyscus leucopus and Cle thrionomys gapperi suggest that a significant proportion of white pine seed s is eaten at time of detection; while red oak acorns are more likely to be cached. Captive Peromyscus leucopus cached;Ind ate significantly more red oak scorns than Clethrionomys gapperi. These results suggest that red oak m ast may be more important in overwintering success in Peromyscus than in Cl ethrionomys. Nevertheless, both species did consume red oak acorns, suggest ing that in southern Maine these species are not substantially inhibited by high tannin levels in red oak scorns, as has been suggested by researchers elsewhere.