Date of Graduation

12-2024

Document Type

Thesis

Degree Name

Master of Science in Biology (MS)

Degree Level

Graduate

Department

Biological Sciences

Advisor/Mentor

DeGregorio, Brett A.

Committee Member

Roberts, Caleb P.

Second Committee Member

Chiavacci, Scott

Third Committee Member

Middaugh, Christopher

Fourth Committee Member

Mortensen, Jennifer L.

Keywords

Avian Conservation; DNA Metabarcoding; Invasive Species; Ornithology; Wild Pigs; Wildlife Occupancy

Abstract

Invasive species, particularly wild pigs (Sus scrofa), pose a significant threat to native ecosystems through both direct and indirect impacts. Wild pigs are large-bodied omnivorous species that can consume a wide variety of plants and animals and are known for destructive foraging behaviors, which likely threatens avian communities through habitat alteration and can impact the long term structure of ecosystems where they are present.

In chapter 1, we used a combination of avian point count surveys, vegetation assessments, and camera trap surveillance to quantify how the occupancy of breeding birds in bottomland hardwood forests changed in relation to wild pig relative abundance and measurable ground disturbance. We used Bayesian Spatial Multi-Species Occupancy Models to correlate avian occupancy with hog impacts and vegetation structure. Avian community occupancy declined with increasing hog disturbance but not hog abundance.

In chapter 2, we investigated the diet of wild pigs using DNA metabarcoding to analyze fecal samples collected across four seasonal periods. We found that wild pig diet was highly diverse and included at least 74 plant families and 106 genera but was dominated by plant matter primarily of three families—Fagaceae, Poaceae, and Asteraceae. Seasonal variations indicated that hard mast was a primary food source in fall and winter, while herbaceous vegetation peaked in spring. We documented 23 species of vertebrates, consisting of mammals, birds, fish, frogs and turtles. Vertebrate consumption constituted ~17% of wild pig diet.

Our research found that hog disturbance has a weak but ubiquitous impact on avian community occupancy and that hog diet is highly variable, adaptable and wild pigs could potentially cause long-term alterations to habitat structure.

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