Master's Theses



Degree Name

Master of Science (MS)


The North American landscape is becoming increasingly fragmented, resulting in habitat patches with decreased area and increased isolation. Often, these patches exist as protected areas, such as national parks. The Theory of Island Biogeography is frequently used as a model for these patches, where each park serves as an ‘island’ surrounded by a ‘sea’ of human-altered habitats. As such, species richness and extinctions in a park might be explained by its area. For this study, I used regression models to examine the relationship between richness and area, as well as extinctions and area, for mammals and birds in national parks. Mammal models were also constructed without rodents. Due to their relatively small size, rodents have a low detectability, and are often under surveyed. As a result, excluding them might improve my models. Additionally, because area is unlikely to be the only factor influencing species retention, I also included national park age, national park latitude, and national park longitude as predictor variables. I found some support for the relationship between area and species retention in national parks. Both bird models indicate that area had a positive relationship with species retention while area did not have a significant relationship with any of the mammal models. Understanding the biogeographic features affecting species retention in national parks allows managers to develop more informed management plans. It is important to preserve the area of national parks to conserve biodiversity in and around the parks by limiting the future effects of fragmentation.


Dr. Robert Channell

Date of Award

Spring 2019

Document Type



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