Abstract:
Spotted salamanders (Ambystoma maculatum) are terrestrial amphibians that live in upland habitats as adults and migrate to ponds during the reproductive season to breed and deposit their eggs. However, not all adults in a population will migrate to breed each year. Whether or not an adult spotted salamander will breed in a year is affected by environmental factors, although it is unknown which factors have the greatest influence. On Penn State Behrend’s campus, the number of migrant, breeding spotted salamanders varies cyclically with peaks every 2-3 years. The focus of this research was to determine which environmental factors contribute to cyclical variation in the size of breeding salamander populations. Environmental data gathered from NOAA Local Climatological Database (LCD) was organized to determine monthly and seasonal temperature, precipitation, and humidity data for the spotted salamander breeding season in years that breeding population sizes at Penn State Behrend are known. Using the environmental data, models were created to determine which environmental indicators best predict breeding population size in a particular year. These models were used to predict Spring 2022 salamander population numbers and then validated with field sampling. During Spring 2022 salamanders were captured from campus sites, photographed, sexed, weighed, and tagged with visible implant elastomer (VIE). Mark-recapture data was used to estimate population size and then compared to predicted values determined from the models. Understanding the environmental factors that influence yearly breeding populations will help us to understand when populations are declining versus when breeding individuals are only out in relatively low abundance.
Team Members
Maille Larmon | (Lynne Beaty) | Penn State Behrend
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