Dr. Chelse Prather
Across the United States, land managers are struggling to cope with a relatively new invasive species, Callery pear (Pyrus calleryana). Callery pear is currently one of the most important invasive species threatening prairies and early successional habitats in Ohio and the Midwest, and yet, no viable means of control exists for this species. This species is relatively resistant to herbicides and resilient against prescribed cutting and burning. One potential management of invasive species is biocontrol, or the intentional introduction of natural enemies to control the growth and propagation of a target organism. Previous experiments with Callery Pear have examined herbivory by large animals, thus, an important knowledge gap exists in the interactions between native insect herbivores and the woody plant. We conducted a month-long field enclosure experiment where we manipulated the species richness of native orthopterans in enclosures with either a Callery Pear sapling or a similar native tree sapling, American Basswood, and destructively measured the biomass of each tree and the vegetation in each enclosure. We then calculated the percent change in biomass between the treatments and controls to determine if varying the orthopteran species richness had any effect on plant growth. We found that in treatments where there was a high species richness of orthopterans, Callery Pears were over 100% bigger relative to controls. This result was opposite to our prediction that a higher diversity of herbivores would lead to an increase in herbivory and thus a decrease in biomass. This phenomenon should be studied further in order to understand how intentional reinstatement of insect diversity to early successional areas by environmentalists may actually be helping invasive species to grow more rapidly.
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Gawkins, Kaitlin, "The Prickly Problem of Pears Potential Effects of Native Orthopteran Herbivory on an Invasive Woody Plant" (2019). Honors Theses. 212.