Date of Award:

5-2026

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Committee Chair(s)

Karen Kapheim

Committee

Karen Kapheim

Committee

Susannah French

Committee

John Stevens

Committee

Amita Kaundal

Abstract

Rock Iguanas are large, endangered lizards found throughout the Northern Bahamas that have become popular attractions for tourists visiting the islands. When tourists feed these iguanas, often giving them foods like grapes, lettuce, and other items that aren't part of their natural diet, it changes what the animals eat and can affect their health. At the same time, these iguanas also face natural challenges throughout the year, especially during breeding season when their bodies and behaviors change significantly. 

This research explores how both human activities, specifically ecotourism, and natural seasonal changes impact the health of Rock Iguanas, with a particular focus on the community of bacteria living in their digestive systems, called the gut microbiome. Just like in humans, this community of microscopic organisms plays a crucial role in digestion, immune function, and overall health. 

The first chapter of this research took advantage of an unplanned "natural experiment" that occurred during the COVID-19 pandemic. When the pandemic began in 2020, tourism to the Bahamas came to an abrupt halt, meaning that for the first time in decades, Rock Iguanas on popular tourist islands were no longer receiving food from visitors. By comparing health data and gut bacteria samples collected from iguanas before the pandemic (2018-2019) to samples collected after tourism stopped (2021), we could see what happened when these animals suddenly returned to eating only their natural diet. The study included iguanas from nine different islands with varying levels of tourism activity, as well as both subspecies of Rock Iguana found in the Bahamas. The results showed that when tourist feeding stopped, the bacterial communities in the iguanas' guts increased in diversity and abundance. These changes were connected to changes in the animals' immune systems and cellular stress. More importantly, the two different subspecies of Rock Iguana responded differently to these dietary changes, showing that even closely related animals can have unique health responses. 

The second chapter examined how natural seasonal cycles and differences between male and female iguanas affect their health and gut bacteria. Samples were collected during two key times of year: the breeding season in June and the post-breeding period in September. During the breeding season, female iguanas had less gut bacterial diversity compared to males and females after the breeding season. This likely reflects the enormous physical demands of reproduction; female iguanas must produce and lay eggs, which requires significant energy and can change their eating patterns and body condition. Our study also found that various health indicators, including blood sugar levels, cellular stress markers, and body weight, were associated with changes in the diversity of gut bacteria. However, despite these seasonal changes, the overall bacterial community remained relatively stable throughout the year. 

Together, both chapters provide important insights for protecting these endangered iguanas. They demonstrate that both human activities and natural biological processes create distinct changes in the iguana gut microbiome, and they identify specific biological markers that can help scientists monitor these changes. Our research also highlights the importance of considering both human impacts and natural cycles when developing conservation strategies for threatened wildlife. It also shows how studying multiple populations under different conditions can reveal complex patterns in how both human activities and natural processes affect animal health, with different responses depending on species and sex. Most importantly, this work provides evidence that ecotourism, while potentially beneficial for conservation funding, does alter wildlife health in measurable ways and that reducing these impacts can help animals recover, at least partially, toward their natural state.

Download

Available for download on Thursday, May 01, 2031

Included in

Biology Commons

Share

COinS

Copyright for this work is retained by the student. If you have any questions regarding the inclusion of this work in the Digital Commons, please email us at .