Publication Details

Vegetation and invertebrate community response to eastern hemlock decline in southern new England

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Ingwell, Laura L.; Miller-Pierce, Mailea; Trotter, R. Talbot; Preisser, Evan L.

Year Published



Northeastern Naturalist. 19(4): 541-558.


The introduction of Adelges tsugae (Hemlock Woolly Adelgid [HWA]) to the eastern United States has had a devastating impact on Tsuga canadensis (Eastern Hemlock). Although much research has been done to assess HWA impacts on ecosystem processes and vegetation structure, few researchers have examined community-level changes in highly infested forest stands. Here we assess the impact of Eastern Hemlock mortality on vegetation and invertebrate diversity and community structure by comparing low-impact (healthy) stands and stands heavily impacted by HWA. We sampled the vegetative and invertebrate diversity of 8 sites (4 low impact and 4 high impact) in the summer and fall of 2008. We found a shift in the understory plant community and the canopy and subcanopy arthropod communities. Herbaceous plant species richness was significantly higher at high-impact sites, with Betula lenta (Black Birch) being the most common woody species. Overall, forest invertebrate community diversity (measured using the Shannon-Weaver diversity index) was greater in high- versus low-impact sites. Of the 21 indicator species significantly associated with a given forest type, 14 and 7 species were associated with high- and low-impact forests, respectively. Variation in arthropod community structure was driven by above-ground differences; ground-level arthropod community composition did not differ between high- and low-impact sites. These results demonstrate some of the biodiversity impacts that can result from the invasion of an exotic insect into forested systems.


Hemlock Woolly Adelgid; Arthropod


Favret, C.; Havill, N.P.; Miller, G.L.; Sano, M.; Victor, B. 2015. Catalog of the adelgids of the world (Hemiptera, Adelgidae). ZooKeys 534: 35-54. doi: 10.3897/zookeys.534.6456

Last updated on: November 15, 2016