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Updated: May 11, 2026
08:20
A Method for Quantifying Foliage-Dwelling Arthropods
Published on: October 20, 2019
Foundation species loss affects vegetation structure more than ecosystem function in a northeastern USA forest
David A Orwig1, Audrey A Barker Plotkin, Eric A Davidson
1Harvard University, Harvard Forest , Petersham, MA , USA.
Peerj
|May 3, 2013
Summary
The loss of Eastern North American hemlock (Tsuga canadensis) trees due to insects or logging causes rapid vegetation regrowth, with logging creating larger structural changes than insect damage. Ecosystem function impacts were subtle.
Area of Science:
- Forest Ecology
- Ecosystem Dynamics
- Invasive Species Impacts
Background:
- Foundation tree species like Tsuga canadensis are declining across North America.
- Infestation by the insect Adelges tsugae and salvage logging are primary drivers of this decline.
- Understanding the ecological consequences of Tsuga canadensis loss is crucial for forest management.
Purpose of the Study:
- To investigate the ecological impacts of Tsuga canadensis removal through simulated insect damage (girdling) and logging.
- To compare the effects of different loss mechanisms on vegetation, soil carbon, and nitrogen cycling.
- To assess the short-term and long-term ecological changes in hemlock forest ecosystems.
Main Methods:
- Experimental plots were established with Tsuga canadensis removed by cutting (logging) or girdling (simulating adelgid damage).
- Control plots included undisturbed hemlock and hardwood stands.
- Vegetation richness, understory cover, soil carbon flux, and nitrogen cycling were monitored for five years post-treatment.
- Litterfall and coarse woody debris (CWD) were measured following treatments.
Main Results:
- Overstory basal area decreased by 60%-70% in treated plots.
- Vegetation cover and richness increased significantly in logged and girdled plots, unlike controls.
- Logging caused immediate litterfall reduction and increased CWD, while girdling resulted in a pulse of hemlock litterfall.
- Soil carbon flux decreased by 35% in girdled plots, and ammonium availability increased in both treatment types.
Conclusions:
- The loss of Tsuga canadensis leads to rapid vegetation regrowth, with logging causing more abrupt structural changes than girdling.
- Ecosystem processes are more influenced by overall vegetation cover than by specific species composition.
- The decline of this foundation species will have lasting impacts on forest structure but less pronounced effects on ecosystem function.
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