Emerald Ash Borer in the Ash (Fraxinus spp.)-dominated Tidal Swamps of the Lower Patuxent River, Maryland

Alexander Jacobsen*

*Department of Biology, George Mason University, 4400 University Drive, Fairfax, VA 22030.

Northeastern Naturalist, Volume 27, Issue 4 (2020): 817–840

Abstract
The tidal swamps of the near coastal rivers dominated by ash species (Fraxinus spp.) on the Mid-Atlantic coast of the United States are a globally rare and diverse habitat and, with the invasion of Agrilus planipennis (Emerald Ash Borer [EAB]), are under threat of alteration due to EAB-caused ash mortality. Little to no information exists on the effects that EAB infestation has had on these tidal swamps; therefore, the purpose of this study was to explore the current state of overstory health, regeneration, and herbaceous plant community at an ash-dominated tidal swamp on the lower Patuxent River, MD. It was found that, in comparison to adjacent stands of ash in the bottomland hardwood forest, the tidal swamp had a significantly larger proportion of its stand basal area infested or killed by EAB. On the other hand, the degree of regeneration of ash stems was far greater in the tidal swamp in terms of seedlings, basal shoots, and young trees. Finally, the herbaceous plant communities were determined to be distinct to their respective habitat types and would likely have different responses to the loss of ash. I concluded that the observed effects of EAB infestation were not the same between the habitat types and that the tidal swamp should be considered separately in management plans for EAB in the Mid-Atlantic and Chesapeake Bay regions.

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