Comparison of damage to native and exotic tallgrass prairie plants by natural enemies.

Han, Xuemei; Dendy, Shauna; Garrett, Karen; Fang, Liang; Smith, Melinda

We surveyed the prevalence and amount of leaf damage related to herbivory and pathogens on 12 pairs of exotic (invasive and noninvasive) and ecologically similar native plant species in tallgrass prairie to examine whether patterns of damage match predictions from the enemy release hypothesis. We also assessed whether natural enemy impacts differed in response to key environmental factors in tallgrass prairie by surveying the prevalence of rust on the dominant C4 grass, Andropogon gerardii, and its congeneric invasive exotic C4 grass, A. bladhii, in response to fire and nitrogen fertilization treatments. Overall, we found that the native species sustain 56.4% more overall leaf damage and 83.6% more herbivore-related leaf damage when compared to the exotic species. Moreover, we found that the invasive exotic species sustained less damage from enemies relative to their corresponding native species than the noninvasive exotic species. Finally, we found that burning and nitrogen fertilization both significantly increased the prevalence of rust fungi in the native grass, while rust fungi rarely occurred on the exotic grass. These results indicate that reduced damage from enemies may in part explain the successful naturalization of exotic species and the spread of invasive exotic species in tallgrass prairie.

INVASIVE plants; BASIDIOMYCETES; PHYTOPATHOGENIC fungi; PLANT species; PARASITIC plants; GEOMATICS

Plant Ecology, 2008, Vol 198, Issue 2, p197

1385-0237

Academic Journal

10.1007/s11258-008-9395-0