Movement Patterns, Nesting Ecology, and Nest-site Selection of the Federally-listed Bog Turtle in Maryland
Movement Patterns, Nesting Ecology, and Nest-site Selection of the Federally-listed Bog Turtle in Maryland

Author: Nathan W. Byer

Publisher:

Published: 2015

Total Pages: 84

ISBN-13:

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The Bog Turtle (Glyptemys muhlenbergii) is North America's smallest and perhaps most vulnerable freshwater turtle, and very little data exists on nesting ecology and habitat use for this species. I used radio telemetry surveys of female turtles to examine movement patterns, nesting ecology, and nest site selection of Bog Turtles at two sites in Maryland. Home range sizes differed between sites, and females moved larger distances during the nesting season in mid-June. Selected nest locations were near water with low overstory vegetation cover and high sedge cover. Nest success was never above 50% at either site, and one site did not experience any nest success. Many successful nests experienced predation by small mammals or insects before hatchlings emerged. Results from this study suggest that further attention to nesting habitat requirements and nest success patterns in this species is needed, as sites may not achieve sufficient nest success for population persistence.

The Maryland Amphibian and Reptile Atlas
The Maryland Amphibian and Reptile Atlas

Author: Heather R. Cunningham

Publisher: JHU Press

Published: 2018-11-26

Total Pages: 306

ISBN-13: 1421425963

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The definitive resource for finding, identifying, and conserving Maryland’s amphibians and reptiles. Naturalists, herpetologists, and ecologists alike agree that tracking herpetofauna is a challenging undertaking. Scientists are concerned about the decline of once-familiar species, but evidence has often been too anecdotal to support firm conclusions. To better understand the distribution of amphibians and reptiles in Maryland and forecast species' futures in a time of accelerated environmental threats, conducting a comprehensive statewide survey updating 1970s-era distribution maps seemed ideal. However, this endeavor was of an impossibly ambitious scope for scientists alone to tackle. Enter the Maryland Amphibian and Reptile Atlas project, comprising nearly a thousand dedicated citizen scientists who discovered and recorded the locations of herpetofauna throughout every corner of Maryland. In The Maryland Amphibian and Reptile Atlas, Heather R. Cunningham and Nathan H. Nazdrowicz present the findings of this massive undertaking. This definitive guide combines nearly 160 comprehensive new herpetological maps with historical distribution maps and in-depth species accounts. Color photos illustrate the natural history of the 89 species of frogs, salamanders, turtles, snakes, and lizards that call the state home. Essays discuss historical studies, the effects of Maryland's current climate, geology, and habitat diversity—and the myriad conservation issues these animals face. This richly detailed book represents a triumph of citizen science and the culmination of an intensive research partnership. It will appeal to both amateurs and professionals interested in herpetology, natural history, or ecology, as well as those with a special interest in Maryland's biodiversity.

Review of the Ecology and Conservation of the Bog Turtle, Clemmys Muhlenbergii
Review of the Ecology and Conservation of the Bog Turtle, Clemmys Muhlenbergii

Author: R. Bruce Bury

Publisher:

Published: 1979

Total Pages: 16

ISBN-13:

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The bog turtle (Clemmys muhlenbergii) is variously considered to be secretive, uncommon, or threatened with extinction. It has a disjunct distribution in the eastern United States, and populations are restricted to wetlands such as bogs and swamps. The turtle appears to be an omnivore. It is most active in the spring, and the eggs (usually three to five) are laid in late spring or early summer. Sexual maturity in both sexes probably occurs at the plastral length of about 75 mm., when the turtles are 6 to 8 years old. Bog turtles apparently have small home ranges (about 1.3 ha or smaller). Other population features are poorly known. There is concern for the plight of the bog turtle because of the continual loss of wetland habitat and irresponsible collecting. A thorough survey is recommended to delineate the occurrence and abundance of the remaining populations of the species throughout its range.

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.

Conservation and Ecology of Turtles of the Mid-Atlantic Region--a Symposium
Conservation and Ecology of Turtles of the Mid-Atlantic Region--a Symposium

Author: Christopher W. Swarth

Publisher:

Published: 2004

Total Pages: 144

ISBN-13:

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This volume summarizes the scientific papers from a symposium on turtles of the Mid-Atlantic Region of the United States. Several peer-reviewed contributions make up the chapters of this edited volume. A great resource for conservation biologists in the region and turtle biologists world-wide.

Movements, Habitats, and Nesting Ecology of Spiny Softshells in the Missouri River
Movements, Habitats, and Nesting Ecology of Spiny Softshells in the Missouri River

Author: Brian James Tornabene

Publisher:

Published: 2014

Total Pages: 430

ISBN-13:

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Sparse information exists about the ecology of spiny softshell turtles in large rivers and in Montana where they are at the northern extent of their range, disjunct from downstream populations, and a Montana species of concern. We described spatial and temporal patterns in movements, habitats, and nesting ecology of spiny softshell turtles in relation to natural and anthropogenic factors in the Missouri River from August 2009 through July 2012. Movement rates and home ranges were generally highest in summer, and lowest in winter. Turtles aggregated and showed interannual fidelity to active-period and overwintering-period habitats that were distinct and separated by 0.2-23.3 km. Microhabitat characteristics at turtle locations varied between active and overwintering periods; shallow and slow velocity areas were inhabited from May-September whereas deeper areas with moderate water velocities were inhabited from October-April. We located 25 nests in 2011 and 97 in 2012. Nesting followed peak river stage, and occurred mostly in the afternoon when no humans were present. Nesting and emergence occurred later in 2011 than in 2012, but incubation periods for successfully-emerged nests were similar between years, and fewer nests were successful in 2011. Nearly all nests were in mixed-gravel substrates with sparse vegetative cover. Nest sites during the nesting period were lower and closer to water than nest sites during the emergence period. More islands were nested on in 2012 than 2011 and depredation rate was three times lower on islands than mainland shores in both years. Substrate temperatures in simulated nests during the incubation period were warmer in gravel than sand substrates. Flooding in 2011 probably decreased nesting success by inundating potential nesting habitats and reducing habitat availability thereby delaying the onset of nesting. However, nesting habitats are created and maintained by floods. During winter, freezing episodes occurred at all depths in all simulated nests. The northern range of the species is probably limited by incubation period because hatchlings are unable to overwinter in the nest. Preservation of natural streamflow regimes and protection of habitats from anthropogenic disturbance may facilitate continued existence of spiny softshell turtles in the Missouri River in Montana.

Patterns and Consequences of Individual Variation in the Nest-site Preferences of Two Species of Sea Turtle
Patterns and Consequences of Individual Variation in the Nest-site Preferences of Two Species of Sea Turtle

Author: Stephanie Jill Kamel

Publisher:

Published: 2006

Total Pages: 366

ISBN-13: 9780494159668

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Maternal behaviours, such as nest-site choice, can be major determinants of offspring phenotype and fitness. In egg-laying species, incubation environment can influence offspring body size, performance, survival and sex. This thesis focuses on variation among females in maternal nest-site choice and the consequences that this variation can have for offspring survival and performance. I investigated nest-site selection in leatherback (Dermochelys coriacea) and hawksbill (Eretmochelys imbricata) sea turtles at three levels: (i) in two species of sea turtle nesting in different environments, (ii) within populations of the same species and (iii) within individual females both within and across nesting seasons. In both species, evidence was found for individual-level nest-site preferences. This was an unexpected result for leatherbacks, as it had long been assumed that females placed their nests randomly due to the unpredictability of their environment. Results were more striking in hawksbills, with individuals exhibiting remarkably high repeatability for nest-site microhabitat characteristics, both within and across nesting seasons. Some females preferred nesting in the forest, some in the forest edge and others still in open areas. With a few exceptions, hatching success and sea-finding ability were similar in all beach microhabitats. This raises the question of what, if not differential offspring survival, is maintaining these preferences. Frequency-dependent selection, wherein females gain a fitness advantage by producing the rare sex, is one possibility. This idea gains some support from the finding that beach temperatures varied dramatically by microhabitat: nests laid in the forest were exposed to male-producing temperatures while those in less vegetated areas were warmer and more female producing. A related aspect of this work has been to consider the conservation implications of nest-site choice. Using seasonal beach temperatures and the distribution of hawksbill nests, I estimated a balanced primary sex ratio, a situation that is likely to change if the current rates of island deforestation in the Caribbean continue. It also appears that Guadeloupe hosts one of the largest hawksbill populations in this region, indicating that data from this nesting beach are critical for developing a more robust demographic picture of Caribbean hawksbills.