Harvard Forest Research

Impacts of multiple invasive insect pests on litterfall and decomposition dynamics in New England hemlock forests

Principal Investigator: David Orwig
Harvard Forest: Jun 01 2007 - Jun 01 2009:

Abstract:
The recent unimpeded infestation of two invasive insects across the northeastern U.S, hemlock woolly adelgid (HWA) and elongate hemlock scale (EHS) provides an unusual opportunity to examine the ecological impacts of multiple forest pests on a foundation species, eastern hemlock, and on above- and below-ground ecosystem processes. HWA is generating widespread mortality and prompting intensive logging of hemlock from North Carolina to Massachusetts and threatens a range-wide decline or elimination of this ecologically, culturally, and economically important species. Despite recent rapid increases in the abundance of co-occurring EHS, much less is known about its impact on hemlock systems. We propose an in-depth analysis of how HWA and EHS impact litter quality, litterfall dynamics, and decomposition rates. A conceptual framework of ecosystem response explicitly compares nutrient dynamics between HWA and EHS infested forests. In addition, because the species commonly co-occur we can examine how simultaneous feeding by both pests affects ecosystem function. :