Invasive species trends in Northeast Temperate Network park forests

Miller KM, Seirup CE, Weed AS. 2018. Invasive species trends in Northeast Temperate Network park forests. National Park Service, Northeast Temperate Network

From the abstract: "The Northeast Temperate Network (NETN) has been monitoring forest health in a network of permanent forest health plots spanning 8 northeastern national parks since 2006. Over this time, parks forests have encountered multiple agents of change, including extreme storm events, such as Hurricane Sandy in 2012 in Morristown National Historical Park (NHP) in NJ, new infestations and the subsequent impacts of emerald ash borer in Roosevelt-Vanderbilt National Historic Site (NHS) in Hyde Park, NY, increased impacts from deer overabundance in nearly all but Acadia National Park (NP), and new invasions and expansion of exotic plant species. Here we present preliminary findings from the last 13 years of monitoring in NETN park forests, with special emphasis on trends in invasive plants. We used linear mixed models and generalized linear mixed models for a range of invasive metrics to determine how invasive plants are changing over time and potential implications for native plants. We assessed multiple scales and metrics of invasion, including proportion of plots invaded, frequency of 1m2 quadrats invaded, average percent cover of invasives, and invasive species richness. We assessed trends in invasive plants overall, and by the following guilds: trees, shrubs/vines, graminoids, and herbs. Parks vary considerably in their degree of invasion, with Acadia NP being the least invaded and Morristown NHP the most invaded. However, at all scales and in nearly every park, a consistent trend has emerged: invasive shrubs/vines continue to invade new areas and increase in abundance where they already occur. These trends are especially strong where major forest disturbances have recently occurred, such as Hurricane Sandy in Morristown NHP. Results indicate that eradicating invasive shrubs and vines, such as Japanese barberry (Berberis thunbergii), oriental bittersweet (Celastrus orbiculatus), and exotic bush honeysuckle (Lonicera spp.), before they become established should be a high management priority. Managing existing populations of exotic shrubs and vines is also necessary to keep them from continually expanding and invading new areas."

Type
Poster
Authors
Miller, Kate; Seirup, Camilla; Weed, Aaron
Date of Issue
2018-10-20
Publisher
National Park Service, Northeast Temperate Network
Units
ACAD , NETN
Keywords
Education, forest communities, forest structure, monitoring, old-growth forest, plant communities, plots, Research & Studies, succession, trees

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