Red Maple Seedling Survival Rate in a
Davidson College Ecological Preserve Forest
Investigations of many large forest ecosystems have documented that white tailed deer (Odocoilus virginianus) populations have reached densities that threaten the regeneration of forest canopy trees throughout much of North America. The Davidson College Ecological Preserve (DCEP) represents a set of small, fragmented forest habitats, and many of these fragments have high edge to area ratios that may foster extremely high deer densities. We conducted an experiment to determine if white tailed deer adversely affected seedling survival of a hardwood canopy species, red maple (Acer rubrum), in one DCEP mixed pine hardwood forest. We randomly selected 3 spatial blocks within a 0.5 ha area and established 3 plots in each block. One plot used metal caging to exclude all potential mammalian herbivores, another excluded large herbivores, but allowed entrance by small mammals, and the third was a completely exposed control. We transplanted 50 first year red maple seedling into each plot and then monitored them for survival from June to November, 2016. Red maple seedlings in the exposed plots in all three blocks showed approximately 50% less survival than either of the two caged treatments. The two caged treatments showed similar survival in all blocks. These results suggest that mammalian herbivory has the potential to reduce red maple regeneration in the forest studied. However, the similar survival rates in the two caged treatments could result from a cage effect that discouraged small mammals from entering the exclosures or reflect low levels of small mammal herbivory on red maple seedlings. Results of a follow up experiment suggest that small mammals visit control plots and plots with cages that exclude deer but provide entrances large enough for small mammals at similar rates. Our results indicate that deer may be the main animal source of red maple seedling mortality in the forest studied.
