Amidst massive losses in biodiversity, it is vital to identify the factors driving species declines. The main objective of this research was to assess dietary differences between Storeria dekayi and Thamnophis sirtalis and their less abundant and more geographically restricted sister species, Storeria occipitomaculata and Thamnophis butleri, in Illinois and Michigan. I hypothesized that greater abundance and more cosmopolitan distribution are associated with consuming a wide variety of prey and more nonnative prey. To assess diets, I conducted field surveys of Storeria and Thamnophis and analyzed DNA metabarcoding data from fecal samples. I found no significant difference in the dietary diversity or proportion of nonnative prey in the diets of Storeria or Thamnophis. The diet of S. occipitomaculata was dominated by Deroceras laeve (native), whereas T. butleri specialized on Lumbricus rubellus (nonnative). In order to protect rare snake species from decline, we must preserve important predator and prey habitats.
","abstract_html":"<p>Amidst massive losses in biodiversity, it is vital to identify the factors driving species declines. The main objective of this research was to assess dietary differences between <em>Storeria dekayi</em> and <em>Thamnophis sirtalis</em> and their less abundant and more geographically restricted sister species, <em>Storeria occipitomaculata</em> and <em>Thamnophis butleri</em>, in Illinois and Michigan. I hypothesized that greater abundance and more cosmopolitan distribution are associated with consuming a wide variety of prey and more nonnative prey. To assess diets, I conducted field surveys of <em>Storeria</em> and <em>Thamnophis</em> and analyzed DNA metabarcoding data from fecal samples. I found no significant difference in the dietary diversity or proportion of nonnative prey in the diets of <em>Storeria</em> or <em>Thamnophis</em>. The diet of S. occipitomaculata was dominated by <em>Deroceras laeve</em> (native), whereas <em>T. butleri</em> specialized on <em>Lumbricus rubellus</em> (nonnative). In order to protect rare snake species from decline, we must preserve important predator and prey habitats.</p>","abstract_has_math":false,"creators":["Dixon, Molly M."],"institution":null,"degree_name":"Master of Science (MS)","degree_level":"Open Access Thesis","degree_discipline":"Biology","degree_department":null,"school":null,"contributors":["Katherine Greenwald, Ph.D.","Cara Shillington, Ph.D.","Margaret Hanes, Ph.D."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2021,"date_issued":"2021-01-01T08:00:00Z","date_published":"2021-01-01T08:00:00Z","updated_at":"2026-07-24T02:17:40Z","subjects":["Butler's garter snake","Dekay's brown snake","Diet","DNA barcoding","Eastern garter snake","Red-bellied snake","Biology","Ecology and Evolutionary Biology"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://commons.emich.edu/theses/1111","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Katherine Greenwald, Ph.D.","Cara Shillington, Ph.D.","Margaret Hanes, Ph.D."]},{"key":"dc:creator","label":"Author","values":["Dixon, Molly M."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2022-01-31T08:00:00Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Biology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Open Access Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science (MS)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Butler's garter snake","Dekay's brown snake","Diet","DNA barcoding","Eastern garter snake","Red-bellied snake","Biology","Ecology and Evolutionary Biology"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://commons.emich.edu/theses/1111"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Amidst massive losses in biodiversity, it is vital to identify the factors driving species declines. The main objective of this research was to assess dietary differences between Storeria dekayi and Thamnophis sirtalis and their less abundant and more geographically restricted sister species, Storeria occipitomaculata and Thamnophis butleri, in Illinois and Michigan. I hypothesized that greater abundance and more cosmopolitan distribution are associated with consuming a wide variety of prey and more nonnative prey. To assess diets, I conducted field surveys of Storeria and Thamnophis and analyzed DNA metabarcoding data from fecal samples. I found no significant difference in the dietary diversity or proportion of nonnative prey in the diets of Storeria or Thamnophis. The diet of S. occipitomaculata was dominated by Deroceras laeve (native), whereas T. butleri specialized on Lumbricus rubellus (nonnative). In order to protect rare snake species from decline, we must preserve important predator and prey habitats.
"]},{"key":"dc:title","label":"Title","values":["The relationship between population dynamics and dietary preferences within two snake genera (Storeria and Thamnophis)"]}]}],"canonical_facts":{"dc:contributor":["Katherine Greenwald, Ph.D.","Cara Shillington, Ph.D.","Margaret Hanes, Ph.D."],"dc:creator":["Dixon, Molly M."],"dc:date.available":["2022-01-31T08:00:00Z"],"dc:description.abstract":["Amidst massive losses in biodiversity, it is vital to identify the factors driving species declines. The main objective of this research was to assess dietary differences between Storeria dekayi and Thamnophis sirtalis and their less abundant and more geographically restricted sister species, Storeria occipitomaculata and Thamnophis butleri, in Illinois and Michigan. I hypothesized that greater abundance and more cosmopolitan distribution are associated with consuming a wide variety of prey and more nonnative prey. To assess diets, I conducted field surveys of Storeria and Thamnophis and analyzed DNA metabarcoding data from fecal samples. I found no significant difference in the dietary diversity or proportion of nonnative prey in the diets of Storeria or Thamnophis. The diet of S. occipitomaculata was dominated by Deroceras laeve (native), whereas T. butleri specialized on Lumbricus rubellus (nonnative). In order to protect rare snake species from decline, we must preserve important predator and prey habitats.
"],"dc:identifier":["https://commons.emich.edu/theses/1111"],"dc:subject":["Butler's garter snake","Dekay's brown snake","Diet","DNA barcoding","Eastern garter snake","Red-bellied snake","Biology","Ecology and Evolutionary Biology"],"dc:title":["The relationship between population dynamics and dietary preferences within two snake genera (Storeria and Thamnophis)"],"thesis:degree_discipline":["Biology"],"thesis:degree_level":["Open Access Thesis"],"thesis:degree_name":["Master of Science (MS)"]},"updated_at":"2026-07-24T02:17:40Z"}