Author ORCID Identifier

https://orcid.org/0009-0004-7247-611X

Semester

Summer

Date of Graduation

2025

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Division of Plant and Soil Sciences

Committee Chair

Yong-Lak Park

Committee Member

Elizabeth Rowen

Committee Member

Nicolas Zegre

Abstract

Global climate change constitutes a major threat to biodiversity and ecosystem services of many taxa. The Mid-Atlantic region of the US is expecting to see an increase in extreme precipitation events and flooding. Dung beetles (Scarabaeinae) can tunnel below the soil surface allowing for water to dissipate into the soil rather than sit on the surface and add to flooding conditions. They also can decrease methane emission by burying dung and reduce outbreaks of pests that prefer the moist environment of dung. They contribute roughly $380 million in ecosystem services annually in the United States, yet their services may be stunted by the rainfall and subsequent flooding they help mitigate. To understand the threshold at which dung beetles can maintain their services during rainfall, in Chapter 2, we captured dung beetles twice a week for 24 h and recorded the precipitation amounts for the 24 h period they were captured. The larger tunneling dung beetles (Scarabaeinae) that nest in the soil below the dung pat, responded negatively to increased rainfall, while there was no effect on dung dwelling beetles (Aphodiinae) that live directly in the pat. In Chapter 3, we conducted a field experiment to understand which species would colonize dung at varying amounts of water starting from the amount used in successful lab breeding, to a full flood state where the dung was completely submerged in water. The results of the field experiment indicate that the month in which we conducted the study had an influence on dung beetles present, as well as the amount of water. We saw negative effects of flooding levels of water on dwelling dung beetles (Aphodiinae) in how they colonized and emerged from the dung. The effect of flooding on dung beetles is particularly important because dung beetles already face declines due to anthelmintic treatments used on cattle in conventional farming. Their services are necessary in combatting the effects of climate change on pastures, and bolstering their communities is paramount in securing viable farmland for the future.

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