Distribution and Abundance of Non-native Plant Species at Fort Necessity National Battlefield and Friendship Hill National Historic Site

Zimmerman, Ephraim; Yoder, Jeremy

Non-native plant species were inventoried at Fort Necessity National Battlefield (FONE) and Friendship Hill National Historic Site (FRHI) during vegetation mapping and classification activities.Sixty-four non-native plant species were documented at FONE. The two most widespread non-native plants were multiflora rose (Rosa multiflora), Japanese barberry (Berberis thunbergii) and Morrow’s honeysuckle (Lonicera morrowii). All three species occurred at more than half of the 97 survey points. Several other non-native plants were prevalent in successional old fields, successional forests, and cultural community types. Oak-dominated community types (white oak-mixed hardwood forests and northern red oak-mixed hardwood forests) contained the fewest non-native plants. In contrast, successional old-field types, red maple-black cherry successional forests and tuliptree forests exhibited the highest abundance. In general, non-native plants exhibited a greater percent cover at points beneath open canopies than along roads and trails beneath a closed canopy. Along roads, trails, and transportation rights-of-way, the highest numbers of non-native plant species occurred along paved roadsides in open or disturbed community types (successional old field and tuliptree forest community types) and cultural vegetation patches.Sixty-six non-native plants were documented at Friendship Hill National Historic Site (FRHI). The three most common species were multiflora rose, Japanese honeysuckle (Lonicera japonica) and Japanese stiltgrass (Microstegium vimineum) each occurring in nearly half of the 84 plots surveyed and were present in nearly every community type. Tree-of-heaven (Ailanthus altissima), Japanese knotweed/giant knotweed (Polygonum cuspidatum/P. sachalinense) and reed canarygrass (Phalaris arundinacea), though not widely distributed at FRHI, are serious problems where populations occur, often forming dense colonies and/or monocultures. Similar to FONE, successional old-field community patches and successional hardwood types, such as tuliptree - beech - maple and sycamore floodplain forests had the greatest number of invasive species at FRHI. Likewise, oak-dominated community patches had few non-native species. Mixed forb marsh community patches were near monocultures of reed canarygrass or Japanese stiltgrass.

Distribution and Abundance of Non-native Plant Species at Fort Necessity National Battlefield and Friendship Hill National Historic Site

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