Date of Graduation

12-2019

Document Type

Thesis

Degree Name

Bachelor of Science in Agricultural, Food and Life Sciences

Degree Level

Undergraduate

Department

Crop, Soil and Environmental Sciences

Advisor/Mentor

Savin, Mary

Committee Member

Wood, Lisa S.

Second Committee Member

Miller, David

Abstract

Earthworms are an integral component of the soil ecosystem, impacting factors including soil formation, maintenance of soil structure, and nutrient recycling. Earthworm abundances and distributions are related to abiotic soil properties and can influence the community structure. The goal of this study was to survey earthworm populations across areas of different land management histories and soil characteristics to determine if a relationship between earthworm density and land management characteristics was present. Earthworm and soil samples were collected at irregular temporal intervals from September 2017 to March 2018. In total, five sites were sampled, three at the Botanical Garden of the Ozarks in Fayetteville, AR (garden, restored riparian streambank, and field) and two sites (intermound and mound areas) at Chesney Prairie in Siloam Springs, AR. Samples were collected from 30 cm wide x 30 cm long x 20 cm deep monoliths extracted with a garden spade. Subsamples of the soil were collected, and earthworms were boiled and preserved in 90% ethanol. The earthworm community density per m2 was examined across the five sampling sites. Abiotic characteristics of the soil including moisture, temperature, carbon-to-nitrogen ratio, and texture were examined across three sites from September 2017 to November 2017. Native and exotic genera of earthworms were morphologically identified. Bimastos is a native genus that was observed in the garden sampling site, the most managed site where exotics are often expected to out compete the native species. More exotic species were observed at all sampling sites where adults were detected, which may be due to migration of species or through the transport of soil or plants in a botanical garden setting. If exotic species continue to out compete the natives, soil processes may be altered due to different rates of activities in the soil, which may ultimately affect the other organisms and plants in an undisturbed ecosystem compared to a frequently disturbed system.

Keywords

earthworm; Chesney Prairie; exotic; native; Fayetteville

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