You are here
Harvard Forest REU Symposium Abstract 2013
- Title: Effects of mast seeding on small mammal abundance and diversity in a declining eastern hemlock forest
- Author: Amy M Balint (Portland Community College)
- Abstract:
Eastern hemlock forests are declining throughout their range due to the hemlock woolly adelgid (Adelges tsugae), an invasive phloem-feeding insect. The effects of hemlock mortality and succession on small mammal community structure and interactions are not yet well understood. Mast seeding is an important driver of small mammal population and community dynamics in deciduous hardwood forests, but it is not clear how masting affects small mammals in adelgid-infested eastern hemlock forests undergoing successional change. From 2012 to 2013, small mammal populations in the Simes Tract declined sharply. I hypothesized that low mast production may be a factor, and that as hemlocks are killed by the adelgid and replaced by hardwoods, masting will become a stronger influence on small mammal communities. To assess small mammal abundance and diversity, we placed a grid of 49 Sherman live traps in each of four treatment plots in two replicated blocks. Captured animals were marked, PIT-tagged, and released. Population sizes were estimated using the Schnabel mark-recapture index and species diversity was determined using the probability of interspecific encounter. I predicted that small mammal abundance will be positively correlated with the previous year's seed rain mass. To date, our results show a decrease in all rodent populations from 2012 to 2013 except eastern chipmunks (Tamias striatus) and American red squirrels (Tamiasciurus hudsonicus). Red-backed vole (Clethrionomys gapperi) populations experienced the largest decline. Current data show a positive correlation between rodent capture yield and seed rain mass, indicating that masting may be a factor in this year's low rodent numbers.
- Research Category: Biodiversity Studies
