PARENT SESSION
Monday, August 7, 5:00-6:30 pm
Poster Session 2 - Invasive species
Exhibit Hall, Ballroom Level, Cook Convention Center

Testing the enemy release hypothesis: a comparison of insect herbivory of the exotic Acer platanoides and the native Acer saccharum.

Cincotta, Christy^*,1, Adams, Jonathan¹, ¹ Rutgers University, Newark, NJ

ABSTRACT- The enemy release hypothesis (ERH) states that invasive species have been released from the pressures they experienced in their native ranges, such as predation, herbivory, and parasitism. One way of testing this hypothesis is through the comparison of damage experienced by the invasive species with that experienced by its native congener. In this study, we compared the herbivory of Norway maple (Acer platanoides) with that of sugar maple (Acer saccharum). Norway maple is a European tree species that has become established in natural forest stands in the Northeastern United States. This species has been shown to inhibit regeneration of its native congener, A. saccharum. In order to compare the herbivory of A. saccharum and A. platanoides, autumn leaves were collected from multiple sites in NJ, NY, and PA. Each site contained a one hectare circular plot (r =56.42m) containing a minimum of 10 individuals of each species with dbh > 5 cm. After >90% of the leaves had fallen from the trees, leaves were collected from the top layer of the leaf litter along four transects equal to the length of the diameter of the plot. The collected leaves were returned to the laboratory, where an equal amount of leaves of each species were chosen randomly from the sample. Leaf area loss was determined digitally using SigmaScan software. Data collected thus far has shown that sugar maple experiences significantly more herbivory than does Norway maple. We are extending this study to determine herbivore damage by analyzing living leaves as well as determining which insect herbivores favor each species.

Key words: Invasion biology, Acer, Forest