The Gopher Tortoise is an important component of a number of upland ecological communities throughout the southeastern U.S., but populations have experienced significant declines over the past century, largely in conjunction with the loss of longleaf pine (Pinus palustris) forests. Military installations have preserved large tracts of longleaf pine, often while implementing prescribed fires that mimic natural lightning-ignited fires (frequent low intensity fire is a necessary component of longleaf pine communities), which in turn has provided refuges for many imperiled longleaf associates, including the Gopher Tortoise. Eglin Air Force Base in the western Florida panhandle presents a unique situation in which large tracts of longleaf pine sandhill (suitable Gopher Tortoise habitat) are available, but tortoise sub-populations on base are small, and many tortoises currently inhabit treeless military testing and training ranges (test ranges) rather than typical forested sandhill. My objectives were therefore to identify factors that may have been influencing use of test ranges as habitat by gopher tortoises and that might explain observed differences in burrow densities among sites. In Chapter 1, I compared vegetation structure, composition, and burrow site selection among sites and between forested and test range vegetation types. I also attempted to identify relationships between vegetation characteristics and variation in burrow densities (a proxy for abundance within a given area) among sites. In Chapter 2, I distributed a questionnaire to other military installations throughout the southeast to identify common management techniques used to maintain testing and training areas at other tortoise-occupied military installations, as these techniques likely affect their suitability as tortoise habitat. In Chapter 3, I compared surface activity patterns of juvenile Gopher Tortoises between forested and test range vegetation types, as surface activity in these vulnerable, but important size classes may affect survival rates. I found that test ranges generally had greater herbaceous vegetation cover than forested sites (greater forage availability), were highly species diverse in terms of groundcover plants, and had herbaceous communities that shared a number of common sandhill plant species with forested sites, but also were unique in a number of ways. I also found that adult tortoises (burrow site selection) and juvenile tortoises (surface activity) may have exhibited different behaviors in novel test range vegetation types compared to individuals inhabiting more natural longleaf pine sandhill on base. However, I did not find strong evidence that current vegetation structure or composition was related to observed differences in burrow densities among sites and that other factors might have played a greater role in structuring Eglin's remnant tortoise sub-populations. / Master of Science / The Gopher Tortoise is an important component of a number of upland ecological communities throughout the southeastern U.S., but populations have experienced significant declines over the past century, largely in conjunction with the loss of longleaf pine (Pinus palustris) forests. Military installations have preserved large tracts of longleaf pine, often while implementing prescribed fires that mimic natural lightning-ignited fires (frequent low intensity fire is a necessary component of longleaf pine communities), which in turn has provided refuges for many imperiled longleaf associates, including the Gopher Tortoise. Eglin Air Force Base in the western Florida panhandle presents a unique situation in which large tracts of longleaf pine sandhill (suitable Gopher Tortoise habitat) are available, but tortoise sub-populations on base are small, and many tortoises currently inhabit treeless military testing and training ranges (test ranges) rather than typical forested sandhill. My objectives were therefore to identify factors that may have been influencing use of test ranges as habitat by gopher tortoises and that might explain observed differences in burrow densities among sites. In Chapter 1, I compared vegetation structure, composition, and burrow site selection among sites and between forested and test range vegetation types. I also attempted to identify relationships between vegetation characteristics and variation in burrow densities (a proxy for abundance within a given area) among sites. In Chapter 2, I distributed a questionnaire to other military installations throughout the southeast to identify common management techniques used to maintain testing and training areas at other tortoise-occupied military installations, as these techniques likely affect their suitability as tortoise habitat. In Chapter 3, I compared surface activity patterns of juvenile Gopher Tortoises between forested and test range vegetation types, as surface activity in these vulnerable, but important size classes may affect survival rates. I found that test ranges generally had greater herbaceous vegetation cover than forested sites (greater forage availability), were highly species diverse in terms of groundcover plants, and had herbaceous communities that shared a number of common sandhill plant species with forested sites, but also were unique in a number of ways. I also found that adult tortoises (burrow site selection) and juvenile tortoises (surface activity) may have exhibited different behaviors in novel test range vegetation types compared to individuals inhabiting more natural longleaf pine sandhill on base. However, I did not find strong evidence that current vegetation structure or composition was related to observed differences in burrow densities among sites and that other factors might have played a greater role in structuring Eglin’s remnant tortoise sub-populations.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/94559 |
| Date | 11 October 2019 |
| Creators | Moore, William McGee |
| Contributors | Fish and Wildlife Conservation, Haas, Carola A., Smith, Lora L., Stauffer, Dean F. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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