Graduation Year

2023

Graduation Month

May

Document Type

Thesis

Degree Name

Bachelor of Science – Forestry

School or Department

Wildlife Biology

Major

Wildlife Biology – Terrestrial

Faculty Mentor Department

Wildlife Biology

Faculty Mentor

Creagh Breuner

Faculty Reader(s)

Ben Coleman, Zac Cheviron

Keywords

riparian songbirds, heavy metals, telomeres

Subject Categories

Ornithology | Physiology | Toxicology

Abstract

Mining has left massive environmental and physical scars across the landscape. Aquatic and riparian landscapes in particular have been significantly impacted by traditional mining practices. Waste products left over from hard-rock mining leech heavy metals onto the landscape and these metals spread from headwater streams to major waterways (Lottermoser 2010). Heavy metals have been shown to cause physiological stress and challenges to organisms depending on the metal and the concentration (Baos et al. 2019, Boyd & Rajakaruna 2013). While some mining-impaired areas have undergone restoration efforts, is it enough? Typical restoration methods replace the contaminated floodplain, but not the riverbed itself (Geum Environmental 2015). This raises the concern that heavy metal contaminants from the riverbed are still transferring to riparian organisms through the interconnected food webs. In an effort to assess the risk posed by mining contamination and the success of restoration in these mining-impaired areas, we have collected blood samples from six riparian songbird species to measure heavy metal concentration and relative telomere length (the size of the ends of the chromosomes that protect against replication damage) across riparian sites with different levels of contamination and remediation. Telomere length reflects long-term physiological stress and is considered a biomarker for life span in avian species (Powolny et al. 2020, Wilbourn et al. 2018). Riparian songbirds are an ideal group to assess the impacts of heavy metal contamination in riparian ecosystems because they consume both aquatic and terrestrial insects, putting them at significant risk of heavy metal contamination (Walters et al. 2008, Baxter et al. 2005) and they are considered indicators of ecosystem health. Thus, telomeres are informative of the integrated organismal impacts mining contamination has on songbirds. We found that songbirds at a non-contaminated reference site had significantly longer telomeres than songbirds at two remediated sites, indicating there may be some limitations to ecosystem recovery following remediation. In addition, while the site level pattern of change was consistent across species, we found consistent species differences in telomere length. We also found a relationship between a qualitative measure of fat content and relative telomere length. The results of this study provide broad inference as to the efficacy of current riparian ecosystem restoration of mining contaminated areas and have implications for the adaptive management of songbirds, a group in overall decline.

Honors College Research Project

Yes

GLI Capstone Project

no

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© Copyright 2023 Lillian Krach, Bridger Creel, Megan Fylling, Zac Cheviron, and Creagh Breuner