A survey of non-native plants associated with gravel sediment projects in White Mountain National Forest

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Non-native invasive species (NNIS) , White Mountain National Forest (N.H. and Me.)
Casterline, Jessica
Non-native invasive species (NNIS) are a prominent environmental concern in White Mountain National Forest (WMNF). Non-native plants commonly appear at anthropogenic sites including roads, trails, and other developed areas. Terrestrial invasive plants often appear at these sites after a construction project has been completed. It is suspected that terrestrial invasive plants are transported by gravel brought onto the Forest during construction. Because gravel sources are often near the WMNF, municipalities may be able to address NNIS through land use planning. This research involved a mixed methods approach that included 1) identifying non-native plant species on WMNF at thirtyfive construction sites, 2) determining the source of the gravel used at these sites, and 3) reviewing Master Plans from forty-two towns surrounding the WMNF to determine whether NNIS are a concern at the municipal level and identify what NNIS actions are implemented. The results indicate that non-native invasive plants, including New Hampshire Prohibited plants such as Fallopia japonica, Alliaria petiolata, and Lysimachia nummularia, are appearing at sites post-construction. Plants from WMNF NNIS List A, which includes some New Hampshire Prohibited plants, and other invasive plants of the highest concern, appeared at 37% of construction sites. The gravel sources were identified for 13 of the construction sites and five of those gravel sources were used at more than one construction site. Whether the common NNIS at the construction sites with the same supply of gravel originated from the source is inconclusive, although the combination of site characteristics suggest that gravel pits remain as a prime suspect among the possible vectors. Lastly, there is a limited amount of concern for NNIS at the municipal level and no mention of non-native invasive terrestrial plant management in town Master Plans in the WMNF region. Furthermore, this research will be used by the WMNF to meet and improve NNIS management objectives.