Invasive Plants in Pisgah State Park
D. Moon1, B. A. Thelen1 and K. A. Yard1,2
1Ashuelot Valley Environmental Observatory
2Antioch University New England
Given their propensity for outcompeting and displacing native species, invasive plants pose a significant threat to natural communities (NHDAMF & NHISC 2005). To document current conditions, two surveys independently conducted by New Hampshire Natural Heritage Bureau (NHNHB) and Ashuelot Valley Environmental Observatory (AVEO) explored the extent of invasive plant establishment in Pisgah State Park (Pisgah) in Cheshire County, NH. Six invasive species - common reed (Phragmites australis), Japanese barberry (Berberis thunbergii), garlic mustard (Allaria petiolata), glossy buckthorn (Frangula alnus), purple loosestrife (Lythrum salicaria), and wall-lettuce (Lactuca muralis) - were noted during an ecological inventory conducted by NHNHB (Bowman 2009). In response to the need for further study, AVEO Citizen Scientists carried out a second survey covering all trails and roads in Pisgah. AVEO documented five invasive species, including Japanese barberry, glossy buckthorn, multiflora rose (Rosa multiflora), Oriental bittersweet (Celastrus orbiculatus), and purple loosestrife at 29 trailside locations, and non-native bush honeysuckle (Lonicera spp.) and winged burning bush (Euonymus alatus) at several areas off-trail (Moon et al. 2009). Other invasive plants known to occur in the region, including Japanese knotweed (Polygonum cuspidatum), autumn olive (Elaeagnus umbellata) and common (European) buckthorn (Rhamnus cathartica), were not documented at Pisgah. Both NHNHB and AVEO found invasive plants to be sparsely distributed throughout Pisgah, documenting their presence primarily at John Hill Road, Old Chesterfield Road, and trails near the Habitat Trail/Horseshoe Road trailhead. The majority of occurrences were noted within 0.5 miles of the park’s boundary and generally corresponded with past or present anthropogenic disturbance. Management of existing occurrences, prevention of additional establishment, and implementation of a monitoring protocol in areas of increasing land use are necessary to gauge and curtail the presence and spread of invasive plant species throughout Pisgah.
In southern New England, “large areas of protected forestland are uncommon, conserved forests are largely disconnected, important natural and cultural resources (including many plant and animal species) are vulnerable to loss” (Foster et al. 2005; pg. 2). As New Hampshire’s largest state park, Pisgah State Park’s 13,421 acre mosaic of rugged topography, mature- and old-growth forests, wetlands, mid-succession habitat, and rich cultural history affords an unparalleled setting for conservation, recreation and education, while providing a vast array of ecosystem services. Considering myriad ecological, social, aesthetic, and economic benefits of large tracts of conserved land (Foster et al. 2005), Pisgah requires nothing less than best management practices. This includes monitoring and management of ecological threats, not the least of which is the establishment of invasive plants.
Invasive plants are non-native species that have several characteristics allowing them to
outcompete native plants and negatively impact natural areas. These species reproduce rapidly, grow quickly and often earlier in the season than native plants, and adapt to various environmental conditions (NHDAMF & NHISC 2005). Given these advantages, it is crucial to determine where, and to what extent, invasive plants occur on lands where conservation of natural communities is a priority. Pisgah currently “has relatively few invasive plant species for a property of its size,” primarily because conditions throughout the majority of Pisgah are not conducive to supporting invasive species (Bowman 2009; pg. 21). Several species, however, are present in southwest New Hampshire and have the potential to achieve a greater foothold in the region at large and in Pisgah in particular. Among these are: Japanese barberry, Oriental bittersweet, autumn olive, winged burning bush, non-native bush honeysuckles, purple loosestrife, glossy buckthorn, European buckthorn, Japanese knotweed, common reed and multiflora rose (NHDAMF & NHISC 2005). To date, management of invasive plants in Pisgah has occurred in the John Hill Road area; techniques included herbicide treatments and mowing.
In 2008 and 2009, AVEO trained Citizen Scientists to document the location and extent of invasive plant occurrences in Pisgah. Volunteers visually searched for focal species along all trails and roads throughout the park. The detailed methodology, as adapted from the Rutgers University Invasive Plant Monitoring Project (Rutgers 2009), is available from Moon et al. (2009). Findings of this project paralleled NHNHB’s observations of invasive plants during a park-wide ecological inventory (Bowman 2009).
Invasive species occurrences.—Along 87.5 km (54.4 mi) of trails and roads, volunteers
documented 29 occurrences of one or more invasive species (Table 1). Five species, Japanese barberry, glossy buckthorn, multiflora rose, Oriental bittersweet and purple loosestrife, were observed at least once. Glossy buckthorn was most frequently encountered, followed by Oriental bittersweet and Japanese barberry; the remaining species each were observed at only one location. Generally, abundance was relatively low; the majority (41%) of occurrences were less than three stems, 38% were greater than three stems, while only 10% of occurrences were substantial enough that the ground was covered (Moon et al. 2009).
Table 1. Location of invasive plant occurrences in Pisgah State Park, NH as observed during AVEO’s survey in 2008-2009.
Trail Segment Species Number of Date
Baker Pond Trail none 0 8/31/2009
Beal's Road/Knob Trail buckthorn 2 8/18/2009
Broad Brook Road none 0 7/23/2009
Chestnut Hill none 0 8/13/2009
Davis Hill bittersweet 1 5/21/2009
Dogwood Swamp Trail none 0 10/18/2008
Dolittle Trail none 0 10/10/2008
Fullam Pond Trail none 0 8/18/2009
Hinsdale Trail none 0 8/20/2009
Hubbard Hill none 0 5/21/2009
John Hill Road bittersweet 3 10/10/2008
buckthorn 1 10/10/2008
multiflora rose 1 10/10/2008
Kilburn Loop - East none 0 8/6/2009
Kilburn Loop - West none 0 8/6/2009
Kilburn Road none 0 10/20/2008
Lily Pond Trail buckthorn 2 10/2/2009
Nash Trail (West) buckthorn 1 8/18/2009
North Ponds Trail none 0 9/18/2009
Old Chesterfield Road - Mid none 0 7/24/2009
Old Chesterfield Road - North none 0 10/5/2008
Old Chesterfield Road - South none 0 7/23/2009
Orchard Trail none 0 10/2/2009
Parker Trail none 0 8/13/2009
Pisgah Ridge Trail none 0 10/2/2008
Reservoir Road barberry 1 7/22/2009
bittersweet 1 7/22/2009
Reservoir Trail - North none 0 7/12/2009
Reservoir Trail - South loosestrife 1 6/9/2009
Snowbrook Trail buckthorn 1 10/2/2009
South Link none 0 10/14/2008
South Woods Trail barberry 1 10/24/2009
buckthorn 1 10/24/2009
Unnamed trail between none 0 10/19/2008
John Hill Rd. & Snowbrook Trail
Unnamed trail from none 0 10/12/2008
119 Parking to Reservoir Rd.
Horseshoe Road & barberry 2 10/19/2008
Habitat/Wildlife Trail area buckthorn 10 10/19/2008
Locations of occurrences.—In AVEO’s survey, invasive plants were observed on only ten trails in Pisgah. With few exceptions, these occurrences fell within 0.5 miles of the park’s boundary. The majority of invasives were noted in two areas: John Hill Road and unnamed trails near the Habitat Trail/Horseshoe Road trailhead (Figure 1). The greatest number of invasives was noted along trails in the latter area; volunteers documented ten occurrences of glossy buckthorn and two of Japanese barberry. In the old orchard on John Hill Road there were three occurrences of Oriental bittersweet, one of multiflora rose, and one of glossy buckthorn. Other locations included Beal’s Road (two buckthorn occurrences), Davis Hill (one bittersweet occurrence), Lily Pond Trail (two buckthorn occurrences), Nash Trail (one buckthorn occurrence), Reservoir Road (one occurrence each of bittersweet and barberry), the south end of Reservoir Trail (one loosestrife occurrence), Snowbrook Trail (one buckthorn occurrence), and South Woods Trail
(one occurrence each of barberry and buckthorn).
In addition to the formal trailside surveys, volunteers explored two areas suspected to
have invasives. First, volunteers observed winged burning bush, Japanese barberry, bittersweet, non-native honeysuckles, and glossy buckthorn in the Horseshoe Road trailhead/Habitat Trail area (Figure 2). Second, volunteers documented six occurrences of glossy buckthorn along the 0.5 mile stretch of ROW at Pisgah’s southwestern boundary; most were of moderate abundance (Moon et al. 2009).
Similarly, NHNHB determined that the greatest number of invasives occurred along Old
Chesterfield Road and John Hill Road. Throughout Pisgah, NHNHB observed species including Japanese barberry, Oriental bittersweet, shrub honeysuckles, glossy buckthorn, and purple loosestrife, as well as garlic mustard, common reed and wall-lettuce (Bowman 2009). Most observations of invasive plants corresponded with areas of past or present human land use. Despite the number of occurrences reported, invasive species were not detected throughout the majority of the park; large areas including Pisgah Ridge, the Kilburn Loop trail, Broad Brook Road, and backcountry trails such as the Dogwood Swamp Trail were free of invasive plants.
Currently, Pisgah State Park is predominantly clear of invasive plants (Bowman 2009).
Seven invasive species have been documented in Pisgah, including common reed,
Japanese barberry, garlic mustard, glossy buckthorn, multiflora rose, Oriental bittersweet, and purple loosestrife, as well as wall-lettuce (Bowman 2009; Moon et al. 2009).
Most invasive plant occurrences are of relatively low abundance (Moon et al. 2009).
Areas with the greatest number of invasive species generally correspond to those areas with past or present land use (e.g. abandoned homesteads, areas managed for early succession habitat, utility rights-of-way).
DRED, AVEO, and/or other stakeholders will conduct additional surveys of non-native invasive plants
DRED will develop a plan to control existing invasive plants and prevent establishment of new populations as needed.
DRED will apply best management practices to its forestry activities in accordance with Good Forestry in the Granite State (in press 2010).
Figure 1. Invasive plant occurrences in Pisgah State Park, NH as documented by both NHNHB and AVEO, including those on the powerline right-of-way at the south edge of the Park.
Figure 2. Location of invasive plants near the Horseshoe Road trailhead in Pisgah State Park, NH, as documented by AVEO in fall 2008. Map includes off-trail observations.
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