DISPERSAL IN THE WOOD FROG (RANA SYLVATICA): IMPLICATIONS FOR GENETIC POPULATION STRUCTURE.

Area of Science:

• Ecology
• Evolutionary Biology
• Population Genetics

Background:

• Understanding amphibian population structure is crucial for conservation.
• Wood frogs (Lithobates sylvaticus) are key indicators of Appalachian pond ecosystem health.
• Previous studies suggested metapopulation dynamics in similar species.

Purpose of the Study:

• To investigate the dispersal patterns and genetic structure of wood frogs in Appalachian Mountain ponds.
• To determine the fidelity of adult and juvenile wood frogs to breeding ponds.
• To assess if wood frogs exhibit a metapopulation structure.

Main Methods:

• Mark-recapture of juvenile and adult wood frogs across five Appalachian ponds.
• Estimation of effective population sizes and genetic neighborhood radii.
• Analysis of genetic variance and population differentiation based on dispersal data.

Main Results:

• Adult wood frogs demonstrated 100% breeding pond fidelity.
• Approximately 18% of juvenile wood frogs dispersed to different breeding ponds.
• Effective population sizes were smaller than census sizes, with genetic neighborhoods averaging 1,126 meters.
• Ponds within 1,000 meters showed minimal genetic differentiation, while those further apart exhibited higher differentiation.
• Wood frogs did not display a metapopulation structure.

Conclusions:

• Adult wood frogs exhibit strong site fidelity, ensuring population stability within established breeding ponds.
• Juvenile dispersal contributes to gene flow, but limited genetic differentiation suggests restricted connectivity between more distant ponds.
• The observed patterns do not support a metapopulation structure for wood frogs in this Appalachian landscape.