Nesting Ecology in Reintroduced Alligator Snapping Turtles (Macrochelys Temminckii)
Nesting Ecology in Reintroduced Alligator Snapping Turtles (Macrochelys Temminckii)

Author: Jessica Leigh Miller

Publisher:

Published: 2012

Total Pages: 120

ISBN-13:

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The alligator snapping turtle (Macrochelys temminckii) is a large freshwater species that has experienced population declines throughout much of its range. In an effort to reestablish an extirpated population in southern Oklahoma, adult M. temminckii were released at Tishomingo National Wildlife Refuge in 2007. I investigated several aspects of M. temminckii reproductive biology within this reintroduced population, including nest-site selection, reproductive and nest predation rates, and patterns of temperature-dependent sex determination (TSD) in natural nests. Water depth two meters from the shoreline and percentage ground cover were important factors in nest-site selection. The nest predation rate was 76% when efforts were made to protect nests and the average clutch size in intact nests was 22.4 eggs. The overall sex ratio in 2010 recruits was strongly female-biased (91.8% female) and a strongly skewed population sex ratio may become a serious threat to this reintroduced population if this trend continues. I also developed a technique to reliably estimate clutch size from predated M. temminckii shell fragments which will improve estimates of mean clutch size (and therefore annual fecundity) for the population. The persistence of several adult M. temminckii and evidence of successful reproduction and recruitment are positive signs, but post-release monitoring will need to continue for several more years in order for this reintroduction to be considered a success.

Ecology of Hatchling Alligator Snapping Turtles (Macrochelys Temminckii)
Ecology of Hatchling Alligator Snapping Turtles (Macrochelys Temminckii)

Author: Sarah Spangler

Publisher:

Published: 2017

Total Pages: 132

ISBN-13:

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Little is known about the first year of life for many of the world’s freshwater turtles. This is due in part to their cryptic nature and the difficulty of locating hatchlings in the wild. The lack of information about this demographically important age group has led researchers to draw conclusions from indirect inferences about survival rates and ecological roles of hatchlings that may or may not be accurate. To begin filling in some of these gaps, I focused on the first year in an alligator snapping turtle’s life. I studied: (1) circadian and circannual patterns of activity, (2) growth rates and how they are related to activity rates, (3) habitat preferences, (4) fall movement patterns, and (5) predation patterns. My study site was within the species’ natural range in southeastern Oklahoma. Unlike adults, hatchlings followed a predominantly diurnal activity pattern for much of the year, with peak activity occurring during the mid-hours of the day. The diurnal habit of hatchlings may be a strategy to temporally partition themselves from nocturnal predators. There were no significant relationships between growth rates and activity rates during any period, potentially due to small sample size. Hatchlings were located in areas of increased cover and shallower water depths, when compared to random locations. Their movement patterns were characterized by an initial movement away from the site of release to a location with suitable habitat characteristics, and they tended to stay at these locations for extended periods. I documented depredation by fish, but not by terrestrial predators such as raccoons.

Reproductive Biology of Alligator Snapping Turtles
Reproductive Biology of Alligator Snapping Turtles

Author: Denise Michele Thompson

Publisher:

Published: 2013

Total Pages: 254

ISBN-13:

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Successful production of offspring (and ultimately grand-offspring) defines organisms' fitness. Therefore, I investigated three critical aspects of reproduction in the alligator snapping turtle (Macrochelys temminckii), a model organism that is of great conservation interest. Specifically, I studied: (1) nesting behavior and (2) maternal reproductive investment patterns in a captive alligator snapping turtle population housed outdoors under semi-natural conditions, and (3) nest predation patterns in a reintroduced population. Both sites were located in the species' geographic range in southern Oklahoma. Females averaged 25 terrestrial forays prior to successfully nesting and average nesting duration was 185 minutes. Nesting activity positively correlated with increasing temperature, but did not correspond with rainfall. Larger females tended to lay larger eggs but the number of eggs per clutch was not related to female size. Instead, females primarily increased fecundity by allocating extra resources to producing more eggs rather than larger eggs. Raccoons (Procyon lotor) are the most important nest predator in the population studied, and I investigated the role of soil disturbance and turtle olfactory stimuli in raccoon responses to artificially constructed alligator snapping turtle nests. Raccoons primarily used soil disturbance cues to detect artificial nests; however, after being detected nests with soil disturbance were more likely to survive an encounter with a raccoon than a nest that lacked visual stimuli. The conspicuous nesting strategy employed by M. temminckii is discussed as a potential evolutionarily adaptive strategy to disguise the exact location of the clutch from predators.

Habitat Use and Movements of Alligator Snapping Turtle (Macrochelys Temminckii) Hatchlings
Habitat Use and Movements of Alligator Snapping Turtle (Macrochelys Temminckii) Hatchlings

Author: Amity Ann Bass

Publisher:

Published: 2007

Total Pages: 106

ISBN-13:

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The objective of this study was to gather data concerning home range, movements, and habitat use of hatchling Alligator Snapping Turtles ... in order to better manage for this species. Nineteen hatchlings were tracked at Black Bayou Lake National Wildlife Refuge during 2006. Ten animals were successfully tracked during the spring and nine during the fall. Hatchlings that were incubated in the laboratory or naturally on the railroad causeway were heavier and had longer carapace lengths than those naturally incubated along the forest-old field edge of the peninsula (p

Aquatic Turtle Community Dynamics in Relation to Reintroduction of Alligator Snapping Turtles, Macrochelys Temminckii
Aquatic Turtle Community Dynamics in Relation to Reintroduction of Alligator Snapping Turtles, Macrochelys Temminckii

Author: Travis L. Anthony

Publisher:

Published: 2013

Total Pages: 114

ISBN-13:

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The alligator snapping turtle (Macrochelys temminckii) is a long-lived species that merits reintroduction because the species has declined significantly throughout its range. The purposes of this study were to: 1) report the findings of a reintroduction project that was initiated in 2008 and 2) to compare habitat associations of all aquatic turtles species in the Caney, Verdigris, and Spring rivers in northern Oklahoma. Alligator snapping turtles were released in the Caney River in 2008, 2009, 2010, and all released individuals exhibited substantial annual growth rates upon recapture 1-3 years later. Additionally, no decline in body condition was observed. Capture probability was estimated to be 30%, and annual survival was estimated to be 64%. This survival estimate may be lowered by dispersal of animals away from the sampling area. Among the three rivers and three tributaries sampled, Pond Creek, a tributary of the Caney River, had the highest diversity. Big Creek, a tributary of the Verdigris River, supported a turtle community that was comparatively dissimilar to other sites sampled, including in comparison to the main channel of the Verdigris River. Possible displacement of Ouachita map turtles (Graptemys ouachitensis) was observed where alligator snapping turtles were introduced.