The Prickly Problem of Pears: Potential effects of native orthopteran herbivory on an invasive woody plant
Across the United States, land managers are struggling to cope with a relatively new invasive species, Callery pear (Pyrus calleryana). At the present, Callery pear is one of the most important invasive species threatening prairies and early successional habitats in Ohio and the Midwest, and yet, there is no viable means of control that is widely used for this species. This is due to the fact that this species is resistant to herbicides and resilient against prescribed cutting/burning. One potential management strategy 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 been limited herbivory by large animals, thus, an important knowledge gap exists in the interactions between native insect herbivores and the woody plant. In order to explore this knowledge gap, 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 the tree and 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 with a high species richness of orthopterans, there was a larger positive percent change in Callery Pear biomass. This was opposite to what we expected due to the fact that, traditionally, a higher diversity of herbivores would lead to an increase in herbivory and thus a decrease in biomass. This 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.
Kathleen A Kargl, Chelse M Prather
Primary Advisor's Department
Stander Symposium poster
"The Prickly Problem of Pears: Potential effects of native orthopteran herbivory on an invasive woody plant" (2019). Stander Symposium Posters. 1610.