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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effects of body size on the survival and timing of emigration of newly metamorphosed Northern Red-legged frogs

Chelgren, Nathan D. 17 June 2003 (has links)
The purpose of this study was to investigate the survival and movements of newly metamorphosed Northern Red-legged frogs (Rana aurora aurora) as they emigrated from two ephemeral breeding ponds. Quantifying survival and movement rates will be important to our understanding how changes to terrestrial and aquatic systems affect behavior and population dynamics. I manipulated food availability for a subset of uniquely marked metamorphic frogs and then analyzed temporal and spatial aspects of their recapture in forest pitfall traps relative to body size and date of metamorphosis. The probability of surviving and emigrating increased strongly with increasing body size and declined for frogs metamorphosing later in the season. Larger body size was associated with earlier emigration and greater correlation of movements with rainfall events. Within a pond, the time elapsed between metamorphosis and emigration was not affected by the pond drying. My results demonstrate that conditions during the tadpole stage which affect body size and the timing of metamorphosis may have a dramatic impact on the performance of frogs during their initial transition into the terrestrial environment. / Graduation date: 2004

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