PARENT SESSION
Poster Session 34: Herbivory
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Deer herbivory and tree seedling coexistence at two different forest types.
Miguel, Bugalho*,1, Ibáñez, Inés2, Clark, Jim2, 1 Centre for Applied Ecology, Lisbon, Portugal2 University Program in Ecology, Durham, North Carolina, USA
ABSTRACT- Vertebrate herbivores may affect the survival, establishment and coexistence of tree seedlings, through selective predation. Ultimately, vertebrate herbivory may also influence the species composition of tree communities. We assessed the effects of deer herbivory on the coexistence of one year and older tree seedlings at two different forest types through a grazing exclusion experiment. Fenced and control plots were established at hardwood and pinewood forest types. Tree seedlings were identified, individually tagged and monitored once a year between 2000 and 2003. The effects of deer herbivory on the survival of one year old seedlings were different from the effects on older seedlings. The proportional abundance of one year old seedlings of Acer rubrum was significantly lower (P=0.003) and of Cornus florida significantly higher (P=0.028) in fenced plots. For older seedlings, Cercis canadensis (P=0.025), Quercus alba (P=0.024) and Acer sacharum (P=0.048) were significantly lower and Quercus velutina (P=0.038) significantly higher in fenced plots. There was also a strong effect of deer (P<0.001) on herb cover with herbs dominating in fenced and hardwood plots. Deer herbivory may affect tree seedling species composition through direct predation or indirectly by changing herb cover and possibly microenviroment conditions for seedling establishment.
Key words: Deer, Herbivory, Seedlings