The hemlock woolly adelgid is an insect native to Asia and likely western North America that was first reported in eastern North America in 1951. Upon its introduction, it colonized eastern (Tsuga canadensis) and Carolina (Tsuga caroliniana) hemlocks, devastating hemlock populations across the eastern United States. Loss of hemlock will greatly affect the structure and function of eastern deciduous forests where these trees serve as a foundational species within the ecosystem. Current methods of eradicating the hemlock woolly adelgid have been unsuccessful, and potential replacement of native hemlock tress with hybridized native hemlocks and Asian congeners is being examined due to increased resistance to the woolly adelgid in some of the Asian hemlock species. Unfortunately, it is unclear if these hybridized hemlock trees will fill the same niche as the native eastern hemlock. Using next generation amplicon sequencing, our study examined how woolly adelgid infestation altered above and below ground archaeal, bacterial, and fungal communities across 4 different hemlock species, Tsuga canadensis, Tsuga chinensis, Tsuga dumosa, and Tsuga sieboldii. Across and within the 4 hemlock species sampled, natural resistance to this invasive insect varied.
Results/Conclusions
Surprisingly, we found no difference in microbial community composition or diversity between trees of the same species with varied resistance to the hemlock woolly adelgid. However, both above and below ground microbial communities varied significantly across the four species of hemlock trees sampled: T. canadensis, T. chinensis, T. dumosa, and T. sieboldii. These results indicate that Asian hemlocks may not fill the same niche in eastern deciduous forests as the native eastern hemlock. Further work should be conducted to determine how differences in hemlock species and associated microbial communities might scale up to alter other organismal interactions involving hemlocks.