Drought and insect herbivory affect soil nutrients and grass production in a northern mixed grassland

Authors: Branson, David - Dave

Submitted to: Entomological Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 8/11/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Climate change is modifying precipitation patterns in grassland ecosystems, which can have strong impacts on plant production, ecosystem function and nutrient cycling, particularly in more semi-arid ecosystems. These impacts also affect invertebrate herbivores given the strong plant linkages. Micronutrient cycling remains poorly understood in most grassland systems, particularly in the context of drought and herbivory. We conducted a manipulative cage experiment combining drought manipulation with four grasshopper herbivory levels and control cages without herbivory to examine the impacts of herbivory intensity and drought on grass biomass and soil nutrient availability. The study was conducted at a northern mixed grass prairie site dominated by C3 grasses in eastern Montana to examine predictions from an earlier study in short grass prairie. Belowground nutrient availability responded to both herbivory and precipitation treatments, but no interactions were evident. Zinc responded to both herbivory and precipitation treatments, while drought positively affected availability of nitrogen. The effects of herbivores on nutrient availability were generally weaker than the effects of drought. Although grass damage increased with grasshopper density, particularly in the average precipitation treatment, plants were able to compensate for the effects of herbivory except at high levels of grasshopper herbivory considered a severe economic infestation.