Analyzing Colony Structural Characteristics to Assess Establishment of Reintroduced Black-Tailed Prairie Dogs (Cynomys ludovicianus)
Date
2024-08
Authors
Berkenkamp, Erin
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Abstract
The reintroduction of a species to portions of its former range where it has become locally extinct presents many challenges. As such, there is a need to develop methods to monitor whether the species has established self-sustaining populations at reintroduction sites. The black-tailed prairie dog (Cynomys ludovicianus; BTPD) has been extirpated from large portions of its historical range, particularly in Texas. Reintroduction of BTPD is an on-going conservation task. My study explored the structural spatial dynamics of BTPD burrows as a potential indicator of colony establishment. I used colony age classes as a surrogate for establishment phase in order to derive hypotheses within the framework of selfish-herd theory. A selfish herd forms and is maintained when prey individuals at the center of a group are safer from predators that are more likely to detect and capture individuals on the margins. Each individual seeks to decrease its “domain of danger” by moving toward the center of the herd. In the case of BTPD, this should result in burrow densities and spacing patterns that reflect greater survival probability at the center of a colony, as would be most likely observed in an established colony. Further, BTPD activity should be most prominent at the center and other center-to-edge differences should exist. I mapped burrows and measured physical characteristics at 14 colonies throughout north and west Texas. I then used ANOVA to test for differences among colony age classes and zones (central vs. peripheral). Although not all hypotheses were supported, field mapping of both newly-reintroduced and well-established colonies revealed that well-established colonies exhibited a consistently high proportion (> 0.9) of active mounded burrows across both central and peripheral zones. Conversely, newly-reintroduced colonies showed a relatively greater proportion of these burrows in the central zone but significantly fewer in the peripheral zone, suggesting an increase in active mounded burrows as colonies mature, specifically towards the colony edge. Therefore, the proportion of active mounded burrows could serve as a practical indicator of colony establishment and inform management decisions, potentially reducing the need for ongoing intervention once parity between zones is observed. Additionally, I investigated the potential of satellite imagery for remote monitoring. Although the satellite imagery analysis was not definitive, it indicated that with further refinement, this technology holds promise for identifying BTPD colonies and assessing areas of activity. Overall, my study provides detailed knowledge of BTPD colony structural characteristics and suggests that monitoring of active burrows is a useful tool in assessing success of BTPD reintroduction.
Description
Keywords
black-tailed prairie dogs, establishment, monitoring, reintroduction, selfish herd
Citation
Berkenkamp, E. (2024). Analyzing colony structural characteristics to assess establishment of reintroduced black-tailed prairie dogs (Cynomys ludovicianus) (Unpublished thesis). Texas State University, San Marcos, Texas.