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Riley, J. L., Tattersall, G., & Litzgus, J. D. , Should i stay or should i go? influence of environmental factors on chrysemys picta hatchling overwintering strategy - abstract. Unpublished paper presented at Program and Abstracts of the Tenth Annual Symposium on the Conservation and Biology of Tortoises and Freshwater Turtles. 
Added by: Admin (06 Jan 2014 18:23:07 UTC)
Resource type: Conference Paper
BibTeX citation key: Riley2012
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Categories: General
Keywords: Chrysemys picta, Emydidae, Habitat - habitat, Nordamerika - North America, Schildkröten - turtles + tortoises, Zeitigung - incubation
Creators: Litzgus, Riley, Tattersall
Collection: Program and Abstracts of the Tenth Annual Symposium on the Conservation and Biology of Tortoises and Freshwater Turtles
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Abstract     
In northern temperate areas, Chrysemys picta hatchlings spend their first winter either aquatically after fall emergence from the nest, or terrestrially within their natal nest chamber with subsequent spring emergence from the nest. The occurrence of these two strategies varies among populations throughout the species’ range, and temporally within the same population; however, the factors that determine the strategy employed by a given clutch in nature are not well understood. Subzero nest temperatures above -4ºC can be survived by hatchlings using freeze-tolerance or supercooling, but lower nest temperatures like those found in the temperate north, can only be survived in a supercooled state. If overwintering strategy maximizes winter survival and is cued by environmental factors, then northern hatchlings should remain in nests when the environment promotes supercooling. Clutches that overwinter in-nest should, as previous research has shown, experience lower fall nest temperatures, soil moisture and vegetation cover, higher nest soil organic content, higher available nest oxygen, and smaller nest soil particle size (all characteristics that promote overwinter survival in a supercooled state) than clutches that experience fall nest emergence. We tested this hypothesis over two field seasons in Algonquin Park, Ontario. Over both 2010-11 and 2011-12, 52 C. picta nests were caged and a data logger was placed in each to record temperature. Soil texture was quantified for each nest. Nest micro-habitat variables were recorded at oviposition and monthly during incubation. None of the environmental factors measured appear to influence overwintering strategy. In contrast to our prediction, hatchlings that overwintered in-nest had better body condition than those that emerged in the fall. As well, fall emergence was associated with presence of Sarcophagid fly larvae infestation. In-nest overwintering was also found to incur a significant fitness consequence, and future field work should be done to compare the costs of overwintering aquatically and terrestrially in C. picta. Knowledge of hatchling C. picta overwintering strategies is predominately based on laboratory studies; our study contributes to understanding this phenomenon in nature.
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