You are here

Harvard Forest >

Harvard Forest Symposium Abstract 2014

  • Title: Isolating the ecosystem effects of ant community change on forest ecosystem processes following hemlock loss
  • Primary Author: Aaron Ellison (Independent)
  • Additional Authors: Joseph Kendrick (Bennington College)
  • Abstract:

    The decline of Tsuga canadensis (eastern hemlock) – an hypothesized foundation species – due to infestation by Adelges tsugae (hemlock wooly adelgid) or salvage logging dramatically affects associated faunal assemblages. Among these, ant assemblages undergo rapid compositional change, with implications for a wide range of ecosystem processes. In the Harvard Forest Hemlock Removal Experiment, T. canadensis in large plots have been killed in place to replicate adeglid infestation or harvested to mimic salvage logging. We added ant exclosure subplots to each canopy treatment and associated control plots to reduce ant activity, and examined how ant exclusion affected decomposition of cellulose and lignin, availability of nitrate (NO3) and ammonia (NH4) availability, and carbon flux (soil respiration). NO3 availability was significantly reduced in ant exclosure plots, whereas the rate of cellulose decomposition differed significantly among canopy treatments. Path analysis revealed that decomposition rates of cellulose and lignin strongly affected on NO3 availability. Taken together, these results indicate that biotic changes directly associated with decline of a foundation species can have cascading effects on core ecosystem processes.

  • Research Category: Biodiversity Studies, Invasive Plants, Pests & Pathogens, Large Experiments and Permanent Plot Studies