Western Pond Turtle Head-starting and Reintroduction; 2003-2004 Annual Report.

Leuven, Susan Van; Allen, Harriet

doi:10.2172/897303

Cited by 3 publications

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“…If there is no suitable terrestrial habitat available for overwintering, as in the Mohave River in the central Mohave desert, then the turtles will not leave the water during winter (Lovich & Meyer, 2002). This plasticity of overwintering behaviour has been mentioned by several investigators (Holland, 1994 ;Hays et al, 1999 ;Van Leuven et al, 2004 ;T. & K. Slavens, D. Anderson, personal communications).…”

Section: Aquatic Turtles -Species With Unknown Anoxia Tolerancesupporting

confidence: 63%

The ecology of overwintering among turtles: where turtles overwinter and its consequences

2006

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Turtles are a small taxon that has nevertheless attracted much attention from biologists for centuries. However, a major portion of their life cycle has received relatively little attention until recently - namely what turtles are doing, and how they are doing it, during the winter. In the northern parts of their ranges in North America, turtles may spend more than half of their lives in an overwintering state. In this review, I emphasise the ecological aspects of overwintering among turtles, and consider how overwintering stresses affect the physiology, behaviour, distributions, and life histories of various species. Sea turtles are the only group of turtles that migrate extensively, and can therefore avoid northern winters. Nevertheless, each year a number of turtles, largely juveniles, are killed when trapped by cold fronts before they move to safer waters. Evidently this risk is an acceptable trade-off for the benefits to a population of inhabiting northern developmental habitats during the summer. Terrestrial turtles pass the winter underground, either in burrows that they excavate or that are preformed. These refugia must provide protection against desiccation and lethal freezing levels. Some burrows are extensive (tortoise genus Gopherus), while others are shallow, or the turtles may simply dig into the ground to a safe depth (turtle genus Terrapene). In the latter genus, freeze tolerance may play an adaptive role. Most non-marine aquatic turtles overwinter underwater, although Clemmys (Actinemys) marmorata routinely overwinters on land when it occurs in riverine habitats, Kinosternon subrubrum often overwinters on land, and several others may overwinter terrestrially on occasion, especially in more southern climates. For northern species that overwinter underwater, there are two physiological groupings, those that are anoxia-tolerant and those that are relatively anoxia-intolerant. All species fare well physiologically in water with a high partial pressure of oxygen (PO2). A lack of anoxia tolerance limits the types of habitats that a freshwater turtle may live in, since unlike sea turtles, they cannot travel long distances to hibernate. Hatchlings of some species of turtles spend their first winter in or below the nest cavity, while hatchlings of other species in the same area, including northern areas, emerge in the autumn and presumably hibernate underwater. All hatchlings are relatively anoxia-intolerant, and there are no studies to date of where hatchling turtles that do not overwinter in or below the nest cavity spend their first winter. Equally little is known of the ontogeny of anoxia tolerance, other than that adults of all species are more anoxia-tolerant than their hatchlings, probably because of their better ossified shells, which provide adults with more buffer reserves and a larger site in which to sequester lactate. The northern limits of turtles are most likely determined by reproductive limitations (time for egg-laying, incubation, and hatching) than by the rigors of hibernation. Mortalit...

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Section: Aquatic Turtles -Species With Unknown Anoxia Tolerancesupporting

confidence: 63%

The ecology of overwintering among turtles: where turtles overwinter and its consequences

2006

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“…We handled all animals in accordance with the Guidelines for Use of Live Amphibians and Reptiles in Field Research (Beaupre et al 2004). From 2000 to 2003, we released yearling western pond turtles on the refuge each summer (Jul-Aug) that had been removed as hatchlings from protected nests and raised in captivity (head-starting;Van Leuven et al 2004). We removed hatchlings from nests in late September-early October and reared them at local zoos for 10-11 months before releasing them on the refuge; we held turtles that had not achieved 50 g mass an additional 12 months before release.…”

Section: Methodsmentioning

confidence: 99%

“…Hatchling turtles came from 2 remnant populations along the Columbia River, approximately 50 km to the east of the study area. We released 40 yearling turtles on the study area in 2000, 38 in 2001, 59 in 2002, and 51 in 2003(Van Leuven et al 2004). We marked all turtles for individual identification with pit tags and with notches filed into marginal scutes.…”

Section: Methodsmentioning

confidence: 99%

Survival and Causes of Mortality of Head‐Started Western Pond Turtles on Pierce National Wildlife Refuge, Washington

et al. 2009

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The western pond turtle (Actinemys marmorata) is a species of conservation concern over much of its range and is listed as endangered in Washington State. From 2000 to 2004, we used radiotelemetry to document survival and mortality factors of head‐started western pond turtles (n = 68) released into Pierce National Wildlife Refuge in southwestern Washington. Survival estimates for first year and older turtles ranged from 86% to 97% and overlapping confidence intervals indicated no detectible differences among age classes or among years. Subadult turtles released at ≥90‐mm carapace length apparently avoided capture by most aquatic predators, indicating that terrestrial predators should be the focus of research and management where predation on larger age‐classes is a concern. High annual survival combined with the documented nesting by ≥7‐year‐old female head‐started turtles in Washington suggest that recruitment of adults is being achieved; however, head‐starting is only practical as an interim solution and strategies for effective removal of aquatic predators must be developed and implemented where natural recruitment is inadequate to maintain populations.

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“…Clemmys [Actinemys 2 ] marmorata (western pond turtle; Emydidae): This species ranges along the west coast of the United States and Mexico, from Baja western California into Oregon and parts of Washington (Ernst et al,'94). Across its range, winters vary from mild to cold, although the hatchlings commonly hibernate inside the natal nest (Buskirk, '91;Reese and Welsh, '97;Rathbun et al, 2002;Van Leuven et al, 2004). As with most species whose hatchlings overwinter in the nest, autumnal emergence does occur occasionally, even as far north as Washington (F. Slavens, K. Slavens, and D. Anderson, personal communications), although it is more common in the southern portion of the range, where hatchlings may emerge in autumn or spring (Holland, '94;Hays et al, '99;Bettelheim, 2004).…”

Section: Aquatic Speciesmentioning

confidence: 99%

Physiological ecology of overwintering in hatchling turtles

2008

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Temperate species of turtles hatch from eggs in late summer. The hatchlings of some species leave their natal nest to hibernate elsewhere on land or under water, whereas others usually remain inside the nest until spring; thus, post-hatching behavior strongly influences the hibernation ecology and physiology of this age class. Little is known about the habitats of and environmental conditions affecting aquatic hibernators, although laboratory studies suggest that chronically hypoxic sites are inhospitable to hatchlings. Field biologists have long been intrigued by the environmental conditions survived by hatchlings using terrestrial hibernacula, especially nests that ultimately serve as winter refugia. Hatchlings are unable to feed, although as metabolism is greatly reduced in hibernation, they are not at risk of starvation. Dehydration and injury from cold are more formidable challenges. Differential tolerances to these stressors may explain variation in hatchling overwintering habits among turtle taxa. Much study has been devoted to the cold-hardiness adaptations exhibited by terrestrial hibernators. All tolerate a degree of chilling, but survival of frost exposure depends on either freeze avoidance through supercooling or freeze tolerance. Freeze avoidance is promoted by behavioral, anatomical, and physiological features that minimize risk of inoculation by ice and ice-nucleating agents. Freeze tolerance is promoted by a complex suite of molecular, biochemical, and physiological responses enabling certain organisms to survive the freezing and thawing of extracellular fluids. Some species apparently can switch between freeze avoidance or freeze tolerance, the mode utilized in a particular instance of chilling depending on prevailing physiological and environmental conditions.

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Western Pond Turtle Head-starting and Reintroduction; 2003-2004 Annual Report.

Cited by 3 publications

References 0 publications

The ecology of overwintering among turtles: where turtles overwinter and its consequences

The ecology of overwintering among turtles: where turtles overwinter and its consequences

Survival and Causes of Mortality of Head‐Started Western Pond Turtles on Pierce National Wildlife Refuge, Washington

Physiological ecology of overwintering in hatchling turtles

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