Temperate-deciduous forests of eastern North America are rich in fleshy-fruited herb species and the vertebrate species which consume them. The variety of herb species potentially leads to competition for frugivore attention, especially in vertebrate-poor second-growth stands, limiting herb population expansion. Yet community-level interactions have rarely been examined in dispersal systems. We used automatic wildlife cameras and cafeteria experiments to test the hypotheses that a) forest herb communities are frugivore-limited, b) that competition can be reduced by specialization in fruit functional types, and c) that secondary seed movement is controlled by granivore seed preference. Five common herb species were examined in long-established second-growth sites on the western Allegheny Plateau of southeastern Ohio.
Results/Conclusions
Fruit removal was commonly delayed 10-14 days after ripeness implying frugivore scarcity. Fruit appearance, size, and presentation significantly distinguished fruit preference by deer, raccoons, mice, turkeys, and small forest birds: Frugivore size ~ fruit size and birds preferred red fruits presented high above the ground. Granivores clearly distinguished between experimentally introduced nonnative species and natives in secondary dispersal and distinguished between native species (not on the basis of seed weight). We conclude that forest herb communities are often frugivore-limited in our region although such selection is partially mitigated by specialized fruiting syndromes.