1 Squam Farm Invasive Management Annual Report 2016-2017

Squam Farm Invasive Management Annual Report 2016-2017

Executive Summary

November, 2017 Kelly A. Omand

NCF’s Squam Farm property, totaling 219 acres, comprises a variety of plant communities that are unusual on Nantucket. Squam Farm’s mosaic of actively managed grasslands, upland and wetland forests, and shrub scrub habitats present a variety of habitat niches for both native and introduced species. While the property’s early-successional communities are vital to NCF’s conservation goals, they also offer footholds for a variety of invasive shrubs, vines, and pasture weeds known to crowd out native vegetation and reduce habitat for native plants and animals. The prescribed sheep grazing project at the property (2005-2015) presented both benefits and challenges for invasive species management. This project concluded in November of 2015, requiring a shift in invasive species management. The change from agricultural/passive recreation to residential/passive recreation land use has removed grazing as a management tool, and has limited our ability to work in certain areas of the property in July through mid-October during the peak herbicide management season.

Project History: Invasive species management began in 2011, when Science & Stewardship staff conducted a property- wide invasive plant survey to evaluate the extent of invasive non-native plant populations at the farm. Within the report, we included a risk assessment associated with each invasive species and specific management recommendations. Most invasive species present at Squam Farm were found to be concentrated at the margins of managed fields, typically just outside fence lines. These edge habitats are ideal for a number of invasive shrubs and vines; the fact that they are outside of managed areas means that they were neither grazed nor mowed and therefore able to mature and produce large quantities of seed. Woody shrubs and vines were the most widespread invasive plants at Squam Farm. Privet, burning bush and barberry were the only woody species found growing in forested areas away from trails; of these, only privet appeared to be present in large numbers. Populations of porcelain-berry vine were much more extensive than previously thought, and appear to be replacing native fox grape along pathways and field edges and in gaps. We also found non- woody invasive ornamental plant species growing along road edges, and pasture weeds concentrated in the farmyard area of the property, particularly where there were permanent paddocks. In 2012, in an area of abandoned old field overgrown with invasives, we began an invasive species prescribed grazing test area. Grazing treatments proved successful for management of the invasive shrubs. The area was expanded to include additional uplands, creating an Invasive Management Pasture that was treated in 2013-2015. Additionally, coordination between the Sheep Grazing Project Technician and the Science & Stewardship staff continued to reduce pasture weeds in the permanent paddocks in 2015. Outlying fields remained free of the most troublesome weeds, with careful ongoing monitoring and management. To enable us to address invasive species occurring in wetlands and buffers, in the spring of 2012 we delineated wetlands adjacent to invasive species populations and filed a Notice of Intent with the Nantucket Conservation Commission, requesting permission to treat in these areas. Upon receipt of an Order of Conditions, we began to treat these populations in late August of 2012. From 2012-2013, we treated all common reed populations, all known barberry bushes, all tree-of- heaven, all burning bush, all Japanese knotweed patches, and all of the cypress spurge populations. In 2014-2015 we focused our efforts on follow-up treatments and initiated management of woody species in forest/pasture edges in two locations. In 2015 we combined late season mowing and backpack pump foliar spraying of weeping lovegrass in an upland area along the driveway near the farmyard. No treatments took place in 2016 due to the shift in management. Dormant season mowing took place as usual within the former pasture areas, which will prevent colonization of the open grassy fields by shrubs. In October 2017, we completed the highest-priority treatments around the house to protect early- successional grassland and shrubland plant communities and limit or prevent recolonization of treated areas following repeated mowing during the summer by the Properties Maintenance staff. Management efforts in 2018 will focus on completing treatments in these areas earlier in the season (mid-August through September) as herbicide treatments tend to be more effective when conducted during warmer temperatures. 1

Management Schedule for Squam Farm 2018

Scheduling of Management Activities Ne ar PRIORITY INVASIVES May Jun Jul Aug Sep Oct Notes House? Common Reed GPS & Photo Found. site, Recheck Pd Site. Treat as needed. Yes Knotweed Recheck sites near entrance and treat if needed. No Weeping Lovegrass Herbicide Aug-early October No Miscanthus Evaluate and manually treat as needed. Yes Bittersweet Evaluate and treat site along trail. Yes Multiflora Evaluate and treat site along trail. No Tree-of-Heaven GPS & Photo. Treat (Renovate 3 spray or Rodeo cut & paint) Yes Burning Bush Recheck Site: Buttonbush pond trail edge. Treat if needed. No Barberry Recheck Sites: Buttonbush & Entrance. Treat if needed. No Lily-of-the-Valley Treat sites early with Rodeo spray No Common Mugwort Treat sites early with Rodeo spray, 2nd treatment if needed Yes

Scheduling of Management Activities Ne ar PASTURE WEEDS May Jun Jul Aug Sep Oct Notes House? Cypress Spurge Check known locations & treat as needed. Yes Canada Thistle Mow? Treat Check pasture areas, Map Distribution, Assess. Yes Bull Thistle Check pasture areas, Map Distribution, Assess. Yes Horse Nettle Dormant season mowing; Assess in June-July. Yes Clammy Goosefoot Dormant season mowing; Assess in June-July. Yes

Scheduling of Management Activities Ne ar BRUSH CUTTING Nov Dec Jan Feb Mar Apr Notes House? Inv Mgmt Pasture Brush- Brush-cut or FECON areas of shrubland in former Inv Mgmt cutting FECON/Brush-cut Pasture if scheduling permits No

Squam Farm Invasive Management Annual Report 2016-2017 Prepared by: Kelly A. Omand November, 2017

INTRODUCTION

This invasive management project encompasses the Nantucket Conservation Foundation’s Squam Farm property (2 Squidnet Way), located in the northeastern region of Nantucket Island, Massachusetts (Figure 1). The total area of Squam Farm is 219 acres, comprised of 10 parcels that were acquired over a period of 20 years. The Foundation’s 294 acre Squam Swamp property abuts Squam Farm’s northern boundary for a total of 513 contiguous acres of valuable conservation land.

Squam Farm is dominated by coastal shrubland (66 acres), followed closely by mowed grassland (42 acres), wooded swamp (35 acres), mixed deciduous forest (33 acres), and shrub swamp (24 acres). Smaller areas of old field (4 acres), open scrub oak (4 acres), agricultural land (3 acres), sandplain heathland (3 acres), developed land (2 acres), and black and pitch pine woodland (2 acres) complete the varied landscape (TNC 1998). A combination of agricultural history and the varied topography of hills and hollows, and rich, moist soils have contributed to high habitat diversity at this site. Unlike the island’s outwash plains, which include mainly drier and sandier soils, Squam Farm’s lower lying areas support forested swamps, shrub swamps, “hidden forests,” and vernal pools, which are all limited habitats on Nantucket (TNC 1998). Interspersed with the forested areas and wetlands are uplands, which have been in agricultural use for many years (Beattie et al. 2009). Prior to NCF acquisition, many of the uplands were mowed annually (Beattie et al. 2009). The Foundation continued to manage some of these upland areas with annual mowing during the dormant (non-growing) season, but also conducted rotational sheep grazing in many of the fields during the spring, summer, and early fall of 2005-2015. Fine-tuning of sheep grazing rotations and a shift to a new mixed breed of sheep resulted in dramatic improvements in woody species management, allowing us to shift some pastures to grazing alone from 2013- 2015 with no need for follow-up mowing.

While the mosaic of habitats at this property makes an important contribution to the biodiversity of the island, its varied land use history has created numerous opportunities for invasive shrubs, trees, and groundcover species to become established. The agricultural areas and the network of walking trails present a number of

challenges in the management of invasive species, particularly early successional shrubs, vines and forbs, forest floor herbaceous species, pasture weeds, and shrubs of shaded forests. Trails and trail edges are mowed to maintain access for staff and visitors. This practice creates additional valuable early successional habitat, but also creates edges that encourage the spread of many invasive shrubs and vines. Past plantings of ornamental species within the property, along with plantings on privately-owned parcels surrounding Squam Farm and Squam Swamp, are sources of seed and can spread into the conservation areas.

Areas that were once mowed or used for grazing prior to NCF ownership, but are now overgrown have succeeded mainly to old field plant communities or to coastal shrubland. These sites are also at high risk of colonization by invasive non-native shrubs and vines. In contrast, dense scrub oak shrublands appear to strongly inhibit invasion and provides habitat for a number of state listed rare species (Swain and Kearsley 2001). Mature forest habitats are at risk from gap-exploiting shrubs and vines, as well as groundcover species with high shade tolerance. Invasive species in all of these habitats may be carried to new areas by wildlife (such as deer and birds), by human activities (farming, passive recreation, or active management, such as mowing or road grading), or by wind and water.

This report summarizes management activities conducted in uplands as well as the management done in wetlands and wetland buffers, which were permitted under Mass. DEP Order of Conditions #SE48-2475.

Project Setup and Survey

In 2011-2012, NCF staff undertook a comprehensive invasive species survey of Squam Farm, documenting the location and extent of invasive plants encountered on this property. Locations of major infestations were recorded using a Trimble Geo XT handheld GPS unit. Areas of invasive weeds within the pastures were mapped as polygons and pictures were taken in 2011 to document pre-management conditions. We did not map Japanese honeysuckle (Lonicera japonica) or grasses such as sweet vernal grass (Anthoxanthum odoratum) or velvet grass (Holcus lanatus), as these species are ubiquitous throughout the property.

In order to prioritize our management planning efforts, we considered which invasive plant species were located within wetland buffers or wetlands, assessed the current extent of invasion by each species, the amount of labor and resources required to manage that species, the likelihood of that species responding favorably to treatment, and the re-invasion pressures from beyond NCF Squam Farm/Squam Swamp property boundaries (Tables 1 and 2). Using ArcMap 10 GIS software, we created maps of the 2011 survey results, depicting the distribution of the 13 invasive plant species and 4 pasture weed species detected at the farm to highlight areas where it was critical to target management (Figures 2, 3, and 4).

Management Goals & Prioritization

This project was initiated to manage a variety of invasive species within inland wetland resource areas and buffer zones, and to conduct pasture weed management in upland agricultural areas. These management activities are designed to reduce or eliminate invasive species populations when feasible and to minimize invasion of new areas, while maintaining native plant diversity and high quality habitat for native wildlife.

All invasive species selected for management within wetland buffers are included in the revised list approved by the Nantucket Conservation Commission as a part of the modifications to the Wetland Regulations in 2013 (TON Conservation Commission 2013). The Invasive Plant Species Committee of the Nantucket Biodiversity Initiative advised the Nantucket Conservation Commission of necessary revisions to the list, based on evidence of species recently observed spreading in natural areas on Nantucket that are not currently included in the Massachusetts Prohibited Plants List [MASSGOV]. Observations from local natural resource managers were substantiated by an extensive review of 14 state and 3 regional or local invasive plant species lists for areas within USDA Plant Hardiness Zone 7b, the climate zone designated for the island of Nantucket [USDA 2012].

Survey data collected since 2011 has enabled us to respond effectively to agricultural weeds in upland areas used for sheep grazing and residential living. Over the years of agricultural use, several large populations of serious pasture weeds became established in the intensively used areas near the house and barn. We reviewed information on the biology of these weeds and began a program of pasture weed management to provide high quality grazing for the sheep, while minimizing the spread of these troublesome plants. Diligent removal of weeds (with assistance from volunteers and NCF Science and Stewardship staff) along with identification of new threats, became one of the responsibilities of the former Sheep Grazing Project Technician. Seeds of native grasses and forbs suitable for pastures were planted to help re-vegetate bare areas of compacted soil, reducing available sites for weeds to become established in the future. With the cessation of sheep grazing, our goals have shifted to managing for ecological purposes except in the immediate vicinity of the house, which is now used as a seasonal residence.

Future surveys and monitoring of Squam Farm will be necessary to protect the property from new incursions of species that are known to occur in nearby areas. These include garlic mustard (Alliaria petiolata) and Japanese stilt grass (Microstegium vimineum) in forested and edge habitats, and spotted knapweed (Centaurea stoebe, =Centaurea maculosa) in road edges and pastures. These species pose a high risk to the plant communities of Squam, and early detection is necessary to prevent their establishment. Continued monitoring will also be required to track those invasives already established at the site, so they may be treated efficiently. 3

Wetland Protection Measures

Squam Farm contains a mosaic of wetlands defined under Massachusetts State regulations as Bordering Vegetated Wetland (310 CMR 10.55) and Land Under Water Bodies and Waterways (Under Steam) (310 CMR 10.56). Additionally, these wetland resource areas are defined in the Nantucket Wetland Regulations as Vegetated Wetlands (Section 3.02) and Inland Water Bodies (Section 3.03). Many of the invasive plants documented in the 2011 survey are found at the edges of managed uplands and along trails, and overlap with either the 100’ or 50’ wetland buffers (Figures 5 and 6). As a result, we requested a waiver to conduct invasive species management adjacent to these wetlands, which is expected to increase wetland function and improve native plant habitat (Figure 7). Management outlined in this report has taken place in uplands, within wetland resource areas, and within the 100ft, 50ft, and 25ft buffers to wetland resource areas (Figures 5, 6, and 7). Wetland boundaries were field delineated in areas where invasive species were documented within the wetland resource area and within the 25ft and 50ft buffers (Figure 7). These delineations served to define the wetland boundaries adjacent to the proposed invasive species work only and do not necessarily encompass the entire resource area.

A number of certified vernal pools were identified at Squam Farm (Figure 8). The work proposed in this management project will not negatively impact these habitats and may enhance the habitat for native plants and wildlife. By managing invasive plants at an early stage, we hope to prevent them from spreading into these sensitive habitats.

Rare Species Protection Measures

The majority of Squam Farm is located within rare species habitat, as outlined by the Massachusetts Natural Heritage and Endangered Species Program in their 2008 GIS map of Priority Habitat for Rare Species and Estimated Habitat of Rare Wildlife [NHESP]. There are also records for a number of state listed rare plant and wildlife species at Squam Farm (Table 3) (Figure 8). The management activities conducted will not negatively impact any of these species and may work to enhance habitat for some of these species. A copy of the Notice of Intent was submitted to NHESP for review in relation to the Massachusetts Endangered Species Act (MESA) and was approved on August 21, 2012 (NHESP No. 12-31207).

Overview of Squam Farm Invasive Plant Species

Woody Shrubs, Trees, & Vines

Woody invasive shrubs documented at Squam Farm included bush honeysuckle (Lonicera morrowii), autumn olive (Elaeagnus umbellata), multiflora rose (Rosa multiflora) and privet (Ligustrum sp.). Additionally, we encountered a single immature burning bush (Euonymus alatus) and three mature Japanese barberry bushes (Berberis thunbergii). Woody invasive vines were concentrated in edge habitat along trails and managed fields including Porcelain-berry (Ampelopsis glandulosa, =A. brevipedunculata) and Oriental bittersweet (Celastrus orbiculatus). One invasive tree species, tree of heaven (Ailanthus altissima), was located near an abandoned foundation close to the house and barn (Figure 2).

Non-Woody Species (Grasses and Forbs) Two patches of non-native common reed (Phragmites australis) were documented on the property, one in a natural wetland and the other in the abandoned cinder block foundation close to the house and barn. Additionally we documented small populations of Japanese knotweed (Fallopia japonica, =Polygonum cuspidatum), cypress spurge (Euphorbia cyparissias), and weeping lovegrass (Eragrostis curvula) along the driveway and near the house and barn area (Figure 3). Since the 2011 survey of Squam Farm, plume grasses (Miscanthus sinensis) have been observed spreading along Nantucket roadsides and in open fields, including Squam Farm. Therefore, we identified plantings of these species in the landscaped areas at Squam Farm as a threat and removed them by digging in 2015-2016.

Pasture Weeds A number of non-native species can become serious pests in pastures and other agricultural areas (Figure 4). They can negatively impact the health of livestock because they contain toxic chemicals, provide lower quality food than desirable pasture plants, and/or are protected with spines or thorns which can deter grazers. These species also have the ability to outcompete native plants, an undesirable trait when both agricultural and ecological goals are deemed important, as at Squam Farm. We identified four weed species that became widespread in the intensively used pastures surrounding the farmyard: creeping or Canada thistle (Cirsium arvense), bull thistle (Cirsium vulgare), clammy goosefoot (Dysphania pumilio, =Chenopodium pumilio), and horsenettle or Carolina nightshade (Solanum carolinense). The populations of weeping lovegrass and cypress spurge discussed above became an increasing concern due to their spread former pastures (Figure 3).

MANAGEMENT METHODS

Hand-removal (Manual)

Manual invasive species management activities included continued mowing of previously established mowed areas, brush-cutting along trail edges, hand digging, and removal of shrubs by hand with a weed wrench. Manual methods were used most extensively in the former pastures, where digging and mowing were used within the permanent paddock areas; mowing was used around the house and barn. We elected not to use herbicides in these areas, to avoid conflicts with resident and livestock needs while the Sheep Program was active. Frequent mowing during the growing season reduced the stored energy in the extensive roots systems of perennial weeds such as creeping/Canada thistle and horsenettle and minimized seed production. Digging of isolated, small horsenettle and Canada thistle patches was effective in reducing their cover when most of the root system is removed. However, we observed expansion of horsenettle into the St. Andrew’s cross field in 2014-2015. Digging of the biennial bull thistle was very effective, minimizing seed set. The Sheep Grazing Project Technician incorporated changes to agricultural practices from 2011-2015, such as rotating feeding and watering stations around the pastures to minimize bare areas of compacted soil, to reduce weed establishment. Fields that were grazed intensively for a number of years were either re-seeded, used less intensively, or allowed to go fallow. Prescribed grazing with livestock has itself been used as a weed control tool by land managers at other sites (Frost and Launchbaugh 2003), and we employed this method in reclaiming an abandoned old field habitat heavily invaded with invasive shrubs and vines (Figure 9). Manual removal outside the former permanent paddocks and farmyard involved small isolated shrubs (typically privet and barberry) found during our surveys or during other project work. These shrubs were pulled by hand or dug using the “Radius Garden NRG Pro Stainless Weeder” which we have found to be a very useful digging tool for tap- rooted forbs and small shrubs [Radius]. Manual removal of ornamental plume grass clumps around the house and at isolated locations where it had seeded into pastures also took place in 2015-2017.

Herbicide Treatment

Herbicides were used in strategic areas at Squam Farm by licensed applicators, following protocols previously established by the Nantucket Conservation Commission. All work in 2012-2017 within wetland resource areas or buffers was conducted using the clip-and-drip method, with the wetland formulated Aquamaster ® or the equivalent, Rodeo ® herbicide mixed at 50%, with added purple marker dye for visibility of treated materials (concentration of the active ingredient, glyphosate was 25% when mixed). All managed knotweed and common reed was bagged, removed from the site and disposed of in the Town of Nantucket’s Solid Waste Digester facility. Bush honeysuckle, barberry, autumn olive, and privet were clip-and-drip treated when not in fruit and

the cut material was allowed to remain onsite, outside of wetland buffers, as these woody materials decompose quickly and are unable to re-establish themselves after being cut. Re-vegetation planting is neither planned nor permitted for these wetland and buffer locations. Instead, natural re-vegetation by surrounding, native vegetation is desirable and should be sufficient.

We used a backpack sprayer to apply Renovate ® triclopyr-based herbicide mixed at 3% concentration to a small patch of cypress spurge in the upland area along the driveway approaching the house in 2014 and 2015 (Figure 3). Spot spraying may be necessary for new patches of cypress spurge that appear along the driveway, as there is a well-established population of this species at an adjacent property along Squidnet Road. Otherwise, weeds in uplands were managed using manual means, with careful timing of grazing and mowing from 2011- 2015. In 2015, we treated large areas of weeping lovegrass along the driveway edge by first mowing and then later in the season treating with a backpack sprayer using 1.5% Rodeo ® mixed with Cide-Kick II ® (a non- ionic spray adjuvant approved for use in wetlands) and Hi-Light ® blue indicator dye, according to Best Management Practices (BMPs). Weeping lovegrass has been documented making rapid inroads into valuable grassland habitat and the area of the infestation was larger than could be effectively treated with manual measures such as repeated mowing and digging (Figure 3). During the Sheep Management Project, sheep avoided eating weeping lovegrass and did not prove successful in reducing cover of this species, so we determined that a combination of mowing and herbicide treatment would be necessary. With the conclusion of the Sheep Grazing program in the fall of 2015, we anticipated that the lack of invasive suppression by sheep during the growing season could require increased manual removal and herbicide efforts. In October 2017, we again treated weeping lovegrass in the driveway edge and surrounding fields as described above.

MONITORING

Invasive species management in wetland buffers and resource areas was monitored by collecting GPS data, recording number of stems or individuals treated in each successive growing season, and/or by taking pre- and post-treatment photos at particular locations. While some infestations were large enough to document their extent as a polygon using a GPS unit, other infestations were too small and the area covered was estimated. We will continue to document any new populations encountered during management. Management of any additional, newly-detected populations is permitted under the Order of Conditions issued for this project, as long as a written request is submitted to the Conservation Commission and BMPs are followed.

Science and Stewardship Department staff coordinated with the Sheep Grazing Project Technician to manage weed species from 2011-2015. Rapid identification of any suspicious potential weeds allowed us to determine whether new plants posed a risk, and to adapt management as needed. With assistance from volunteers and NCF

staff members, monitoring and management efforts greatly reduced cover in the infested areas in the permanent paddocks, minimizing the spread of these weeds to nearby fields. In addition, from 2012-2015 we predominantly used island-grown hay to reduce the risk of new invasive species being introduced. Supplementation with off-island grown hay was necessary in 2014 and 2015 due to lack of local sources. Following the conclusion of prescribed grazing, we have continued to track management activities occurring in uplands and former pastures outside of wetland buffers in order to adapt management practices to be most effective.

MANAGEMENT ACTIVITIES AND RESULTS BY SPECIES

Common Reed (Phragmites australis):

Risk Level: Common reed is highly invasive in wetlands, particularly fresh water wetlands. Squam Farm’s unique forested wetlands would be at risk from invasion if known populations were left untreated. Recent research indicates that common reed does not germinate well from seed (pers. comm. MacKinnon and Steinauer), and there are no other established populations of common reed directly adjacent to the farm. As a result, rapid treatment of these small patches will likely enable us to eradicate this species from Squam Farm, and the probability of re-invasion is low.

Management in 2012-2017: Patches of Phragmites in Squam Farm were small when first documented in 2010 and 2011 (Figure 3). One patch was located entirely within a small pond and consisted of only eight scattered stems in 2010 (Figure 10). The second patch was located within an abandoned cinder block foundation and contained many stems that were flowering and >2 m tall prior to treatment, initially covering 179 m2 and extending beyond the foundation walls (Figure 10). We initially treated both populations on September 10, 2012 using the standard clip-and-drip herbicide protocol, with a 50% Aquamaster ® solution (25% concentration of the active ingredient, glyphosate). Cut stems were bagged and removed to prevent the possibility of seed germination. Follow-up treatments were made to the foundation patch on August 6, 2013, July 18, 2014, and August 8, 2015, using the same method. During treatment of the foundation site, thickets of autumn olive and bush honeysuckle were also cut and treated with the same herbicide solution. These woody stems were left outside the wetland buffer area since they were not in fruit and the stems are incapable of re- establishing after being cut. Treatment did not take place in 2016. On August 28, 2017, we returned to the original foundation patch (now less than 20m2) and treated 25 scattered, mainly stunted stems using the clip- and-drip method.

Results: The 2012 treatment was very successful in reducing the height and number of stems at the abandoned foundation site. No flowering stems were noted in 2013, and by 2014-2017, the patch area was reduced to 8

scattered live stems located only within the cinder block foundation. No live stems were visible at the pond site in 2013-2017. We obtained pre-treatment photos in 2010 at the foundation site, where the common reed was originally taller than the woody vegetation growing out of the foundation (Figure 11). Following treatment, common reed stems were no longer visible because they were shorter than the foundation wall (Figure 11). We did not take pre- or post-treatment photos of the common reed at the pond site, because they were small and obscured by tall native vegetation, making photos ineffective for monitoring. Patch area or point locations were documented with GPS.

Future Management & Monitoring: We will continue to re-visit the common reed sites for at least three years after no stems are observed, to ensure eradication. Until that point we will treat any new stems using clip-and- drip. We have not observed stems at the pond site in five years, indicating that that population may have been successfully eradicated. We will re-check the pond site for potential reestablishment and document the boundaries of the remaining foundation patch prior to treatment in July-September of 2018.

Japanese Knotweed (Fallopia japonica):

Risk Level: Japanese knotweed (formerly known as Polygonum cuspidatum) is highly invasive in wetland buffers, and is often transferred to new sites via the dumping of landscape waste and in contaminated fill (Somers 2008, Seiger 1991). This species forms dense tall stands with low food and habitat value for native wildlife (Maerz et al. 2005). Squam Farm’s wetlands and uplands are at high risk from invasion if left untreated. Fortunately, only two very small patches with a small number of stems were documented at Squam Farm, both along the entrance drive (Figure 3). There is a relatively low risk of re-invasion after these patches are treated, and eradication should be feasible. Introduction of contaminated soil or fill to the property could allow re- colonization, so care must be taken in the future to use only clean fill and loam, and to clean equipment if it has been used in an infested area.

Management in 2012-2017: We treated the small patches of knotweed at the driveway edge (the western point location on the map) in 2012 and 2014 (no live stems were visible at that location in 2013 or 2015) and treated those found in the gully (the eastern point on the map) annually, with the standard clip-and-drip technique using Aquamaster ® or Rodeo ® herbicide in 2012-2017. No live stems were found, so no treatment took place in 2016.

Results: The gully patch had 10-15 stems in 2013, all under 0.25 m in height, and there were no stems found in the road edge patch in 2013 or 2015. The number of stems found and treated in the gully patch in 2015 was less than half that encountered in 2013, and stems were much smaller (<0.25 m tall, <0.5 m2 area). Re-sprouting in the road edge patch in 2014 consisted of 4-6 stems under 0.5 m tall, covering less than 0.5 m2 area, which had 9

grown tall enough to be visible above the surrounding native vegetation. There were no live stems visible in the driveway patch in 2015, and no live stems were found in either patch in 2016. On August 28, 2017, we re- checked both sites and treated six small stunted stems (<25 cm tall) at the gully location; no live stems were found at the original driveway location.

We used a GPS unit to document the locations of each of the patches, but photo-monitoring was not appropriate due to the dense growth of native species obscuring the knotweed stems. The native vegetation was left in place and knotweed stems were individually treated without harming surrounding vegetation.

Future Management & Monitoring: We will continue to revisit the documented patches annually and treat as needed. If any new populations are detected in uplands or wetland buffers, we will treat them as soon as possible. For follow-up monitoring and documentation of any new populations, we will note the size and number of re-sprouting stems and estimate the area covered by the infestation, recording the location of any new populations using a GPS unit. Patches will be considered eradicated after four years with no new stems observed at a site. Stunted stems following treatment are often hidden in the surrounding vegetation, so careful follow-up is essential. A site visit will be scheduled for mid-July or early August of 2018 to look for live stems and treat if necessary.

Autumn Olive (Elaeagnus umbellata):

Risk Level: Autumn olive is highly invasive in edge habitats and old fields, so the open areas of Squam Farm would be at high risk of invasion without management. Autumn olive harbors nitrogen fixing bacteria in its roots and may alter soil and water characteristics (Goldstein and Willard 2008). The fruit of this species is readily dispersed by birds, so complete eradication at Squam Farm is not a realistic goal. Instead, we plan to reduce cover of this species and adapt pasture edge management and trail management to discourage its proliferation.

Management in 2012-2017: In 2012, we cut and tagged autumn olive, privet, and bush honeysuckle (without applying herbicide to the cut stumps) within a formerly used but overgrown upland pasture area. We reintroduced sheep into this area to determine whether they would be effective in preventing re-sprouts and seedling establishment (Figure 9). This reclaimed pasture, known as the Invasive Management Pasture, occupied a partly wooded upland and provided valuable shade and shelter for the sheep. The Sheep Grazing Project Technician increased the fenced area in 2013. Additional invasive bush honeysuckle, autumn olive, and privet were cut in 2014 and the sheep were allowed to graze on the re-sprouts in 2014 and 2015. During those years we also added more plantings of native grasses and forbs grown from locally collected seed or transplants

to encourage growth of suitable grass and forb groundcover. Sheep grazing concluded in this area in 2015, and there was no follow-up manual or herbicide management in 2016 or 2017.

Results: The sheep readily consumed underbrush within the new Invasive Management Pasture to improve access for follow-up management, and they were very effective in minimizing re-sprouting of these woody shrubs. One tagged shrub can no longer be re-located because the sheep were so effective in browsing any re- sprouts and likely pulled out the stump. Prior to sheep introduction, the area consisted of a dense mass of invasive shrubs and porcelain-berry interspersed with native shrubs and grape vine. Photos were taken of the general area during and after grazing (Figure 12), and of the cut tagged stems to assess the degree of re- sprouting and determine whether sheep would consume re-sprouts. While privet re-sprouted vigorously, honeysuckle and autumn olive re-sprouted much less. Sheep grazed on the re-sprouts of all species and maintained them at about 10-30 cm in height. Sheep activity opened up the understory of the area, facilitating access for further treatment and providing suitable habitat conditions for grasses and forbs. Returning to the site in 2014 and 2015, we found that the sheep had continued to browse any re-sprouts from the invasive shrubs that had been cut. Sheep management removed many mature shrubs, reducing the amount of seeds produced and provided additional grazing areas for sheep. With the cessation of sheep grazing, we expect both root-sprouting from established plants and germination of seedlings in this area, which will require follow-up mechanical treatments if we intend to maintain it as an open or semi-open field. Site visits in spring and fall of 2017 indicated substantial cover of grasses and forbs in the open areas, and re-growth of invasive shrubs and vines in the formerly grazed areas.

Future Management & Monitoring: Our original plan was to further expand the Invasive Management Pasture area to treat invasive shrubs and vines within the upland areas of the old abandoned field. With the conclusion of the Sheep Grazing Management Program, future management plans may include expanded brush cutting and/or targeted herbicide treatment. In June of 2017 we visited the site and assessed realistic management options now that it is no longer being grazed. We determined that additional brush cutting in the shrub areas would likely be the best management technique. This action may be implemented in 2018 dependent on staff time and availability.

Burning Bush (Euonymus alatus)

Risk Level: Burning bush can invade forested areas and abandoned fields, as it is adapted to partial or full shade. It can form dense thickets (Somers et al. 2008), so there is a high risk of it becoming a serious pest in the forests and edge habitats of Squam if enough nearby seed sources exist outside the property boundaries.

Burning bush was a popular landscape plant before it was prohibited, and we can expect to see new occasional occurrences from bird-dispersed seed (Anonymous 2005b; Hargrave et al. 2006).

Management in 2012-2017: One individual of this species was documented at Squam Farm in 2012. Since it was encountered in a forested location far from landscaped areas, it likely grew from bird-dispersed fruit. We manually removed this shrub by uprooting it before it reached maturity in 2013 (Figure 13). A second shrub, possibly a re-sprout from a root fragment, was found within a few meters of this location in 2014 and was removed manually (Figure 13). Further re-sprouting was not observed in 2015-2017.

Results: In 2013 we did not observe re-sprouting or growth of new seedlings after removal of the original plant. We documented the exact location of the new shrub (<1.5 m tall) when it became visible in the surrounding vegetation with a GPS unit in 2014. While completing forest survey plots during the summer of 2014, we continued to look for burning bush and privet, which are typically found in forested areas. While we found many additional privet, we did not encounter any other burning bush in the forest. In re-checking the known site in 2015-2017, we did not observe any re-sprouting. No additional populations have been detected during fall walks or field work in Squam Farm/Squam Swamp, indicating that this species is not a widespread invader at Squam.

Future Management & Monitoring: We will return to the site in July-October of 2018, and if any live stems are visible they will be cut and treated with herbicide. The recurrence of this shrub in the same isolated location suggests that it may be able to re-sprout from a small root fragment, and that clip-and-drip treatment with herbicide may be more effective than pulling for future infestations. This shrub is highly visible in fall when the foliage turns red, making autumn a good time to survey for infestations. Any seedlings detected will be removed manually if possible, and we will document number of individuals or stems along with GPS points or polygons to track future infestations. Any larger shrubs may be cut and stump-treated with herbicide.

Japanese Barberry (Berberis thunbergii):

Risk Level: Barberry is highly invasive in mesic forest in Southern New England and the Mid-Atlantic States (Anonymous 2011a, Silander and Klepeis 1999), and therefore is considered a high risk species at Squam Farm and Squam Swamp. It is no longer permitted to sell or transplant barberry in Massachusetts [MASSGOV]. Barberry infestations have been linked to increased threat of Lyme disease, apparently because dense barberry thickets support higher numbers of infected ticks (Williams et al 2009). Barberry was not planted as extensively on Nantucket as it was on the mainland, and the Squam Farm population was not well established. Since the invasion was detected at an early stage, removal of mature individuals will greatly reduce chances of this species becoming a serious pest on the property (Figure 13). Additional small individuals are likely present, so 12 follow-up surveying will be necessary. Pressures of re-invasion from outside the farm are moderate to low. A few large bushes are present on private properties on Wauwinet Road, adjacent to NCF’s Squam Swamp property and these plants produce ample seed. These individuals are not in landscaped yards, so when NCF prepares an invasives management plan for Squam Swamp, requesting permission from abutters to treat them and reduce invasion risk to both Squam NCF properties should be considered.

Management in 2012-2016: We initially treated the three large known individuals at the farm using cut and paint with a 50% Aquamaster ® solution (25% concentration of the active ingredient, glyphosate) in 2012 (Figure 13). The larger shrubs were well-established and were multi-stemmed, so manual removal with a weed wrench was not feasible, and would have caused significant soil disturbance, likely leading to germination of new barberry seedlings. These large individuals each covered an area of 1-3 m2 of ground and were approximately 1.5 m tall. Small individuals that were removed by pulling or with a digging tool were 0.5-1 m tall and had one or two stems (Figure 13). Since there is no danger of cut materials re-sprouting, these were left in place at the site after any visible fruit were removed. An additional medium sized barberry was encountered during forest plot surveys in 2014 and was cut and painted with Rodeo in August of 2015, along with some tiny re-sprouts or seedlings at the Buttonbush Pond location in 2015. No seedlings or re-sprouts were found in 2016 or 2017.

Results: All documented barberry were treated between 2012 and 2013. We did not observe re-sprouting on previously treated plants in 2014, but found some live stems at the Buttonbush Pond location in 2015 that required follow-up treatment. Follow-up checks at herbicide treated locations and surveys for additional plants will be necessary. Photos were not taken prior to treatment due to the dense shrub understory obscuring these plants.

Future Management & Monitoring: We will return to each treated individual in July-October of 2018 to check for re-sprouts or seedlings. Any newly observed plants will be photographed if possible; stem counts, area covered by infestations, and GPS points will be taken. Any plants detected at new or known sites will be treated manually or with herbicide, depending on the size of the individuals.

Bush Honeysuckle (Lonicera morrowii):

Risk Level: Bush honeysuckle is capable of forming extensive dense stands in edges and old fields at Squam Farm, where it threatens early successional habitats, including rare sandplain grassland and heathland species (Figure 14). Bush honeysuckle species are also known to negatively affect native birds and plant communities (Conover 2011, Gleditsch 2010, Batcher and Carlson 2009, Drummond 2005, Gorchov and Trisel 2009) and invertebrates (Love 2006). If managed fields are taken out of a mowing or grazing rotation, bush honeysuckle 13

is likely to spread rapidly throughout these areas. Bush honeysuckle is fairly well established within Squam Farm and adjoining properties, making eradication unfeasible. Our goal is to reduce cover and minimize spread to new areas. Bird dispersed seed from outside Squam Farm would continue to colonize the area, even if all plants within the property were removed.

Management: In 2012, we cut and tagged bush honeysuckle and other invasive shrubs (without applying herbicide to the cut stumps) into the Invasives Management Pasture as described above, and re-introduced sheep into this area to determine whether they would be effective in preventing bush honeysuckle re-sprouts and seedling establishment (Figure 9). In 2014, we cut additional bush honeysuckle within this area and allowed the stumps to re-sprout without herbicide application and be grazed by sheep. We also cut and applied herbicide to the stumps of a cluster of three large honeysuckle shrubs just outside the St. Andrew’s cross field in 2014 and 2015 (Figure 14).

Future Management & Monitoring: In 2017, we re-assessed treatment options of this species based on the conclusion of the Sheep Grazing Program. Some research suggests that, unlike other woody species, spring treatment of bush honeysuckle is more successful (Rathfon and Ruble 2006). We may test spring and fall treatments using herbicide or mowing management as scheduling permits. The 2017 field season did not offer adequate staff time or resources for treatment. Dormant season mowing has continued in former grassy pasture areas, which will limit bush honeysuckle growth. However, we expect both root-sprouting from established bush honeysuckle plants and germination of seedlings within the former Invasive Management Pasture if growing season brush cutting does not occur.

Multiflora Rose (Rosa multiflora):

Risk Level: Old field and pasture/trail edges are at high risk of invasion by this fast growing species, which we encountered in a handful of locations at Squam Farm (Figure15). Multiflora rose forms dense, impenetrable cover with tall arching, thorny vines, and may become a serious pasture pest. This species is scattered on Nantucket, but its seeds are readily dispersed by birds, so re-invasion pressures are moderate at Squam. Also, there will be a significant seed bank beneath any treated shrubs, so diligent follow-up to treat re-sprouts and seedlings will be necessary.

Management in 2012-2017: No multiflora rose plants were treated at Squam Farm during this time frame due to scheduling constraints.

Future Management & Monitoring: A few large multiflora bushes were found at Squam Farm. Most are within 100’ wetland buffers, but are just outside 50’ wetland buffers and located along the margins of managed

uplands/trails (Figure 15). We plan to partner with the NCF Properties Maintenance staff as needed to use a tractor to brush-cut these patches if possible. Manual removal using a bladed weed whacker and/or loppers to cut canes strategically to allow access is an option if access by tractor is not possible. The standard Aquamaster ® or Rodeo ® herbicide treatment described above will be applied to cut stems in July-August. Dormant season cut stump treatment may be more feasible for scheduling, so we may attempt that treatment during the fall or winter of 2018. We will take photos of treated areas pre- and post-treatment. If plants are within pasture areas, they will no longer be kept under control via sheep grazing pressures, so we will need to return for manual or herbicide treatment instead. Small individuals will be manually removed using a weed wrench or Radius digging tool.

Privet (Ligustrum spp.):

Risk Level: The Squam Farm forests and edge habitats are at high risk of invasion because privet thrives in moist soils, disturbed habitats, and both full shade and full sun (Maddox et al 2010). Privets are extremely common on Nantucket as a landscape planting. Common privet (Ligustrum vulgare) and border privet (Ligustrum obtusifolium) are no longer popular as landscape plantings, and the main species now used on island is California privet (Ligustrum ovalifolium) (pers. comm., Craig Beni, Surfing Hydrangea Nursery). Border privet is the only privet species on the Massachusetts Prohibited Plants list [MASSGOV], but a number of states sharing Nantucket’s 7b USDA climate zone have listed additional privet species as invasive (Maddox 2010). Most escaped plants at Squam are likely to be common or border privet, although it is very difficult to identify members of this genus to species definitively unless the shrubs are in bloom (Maddox 2010, Somers 2008). There are no privet species native to New England, so there is no risk of inadvertently harming a native species by treating any privets found growing wild on Nantucket. The main source of the privets found invading forests and edge habitats on Nantucket appears to be abandoned plantings that are no longer pruned. These are able to fruit heavily and the fruits are readily distributed by birds. Re-invasion pressures are high.

Management in 2012-2017: Smaller privets at Squam Farm were removed by hand when encountered while completing forest survey plots, and some larger privets were documented with GPS units for later removal both at Squam Farm and Squam Swamp. A number of privet were cut in the Invasive Management Pasture and allowed to re-sprout and be browsed by sheep as described above for bush honeysuckle. Several very large privet near the hurricane pasture were cut using loppers and hand saw in summer of 2014. In 2014-2017, we intended to begin removing small seedlings and saplings manually with a weed wrench or by hand-pulling, but scheduling constraints did not permit these activities.

Future Management & Monitoring: We encountered a large number of escaped privet, from seedling to mature size, both in forest and along trails throughout the property (Figure 16). Many of the privet were located within 50’ wetland buffers. As time and resources permit, large individuals will be cut at the base and will be stump treated with Aquamaster ® or Rodeo ® herbicide as described above, prior to fruit formation. Assistance from volunteers such as student groups would be useful in the manual stage of this work. Areas treated will be recorded using a GPS unit. Numbers of plants treated and typical size class will be recorded as well. We will take photos of treated areas where feasible to document pre- and post-treatment appearance (in many cases, dense brush obscures the privet). If possible, we will obtain flowering and/or fruiting samples and press these as herbarium specimens, which will allow us to determine which privet species are actively invading at Squam Farm and adjacent Squam Swamp. A number of very large privets were documented with a GPS unit just east of the Squam Swamp Parking Lot; these are acting as a major source of seed and will need to be addressed in a Squam Swamp invasive species management NOI. Any privets found spreading aggressively in natural areas will be considered invasive and may be included in our management activities as scheduling permits.

Oriental Bittersweet (Celastrus orbiculatus):

Risk Level: There is a high risk of bittersweet spreading in forest gaps, along trails, and in pasture edges at Squam Farm and Squam Forest. Oriental bittersweet is an aggressive vine that quickly smothers trees and shrubs; Fast growing vines may girdle trees and amplify wind and ice damage, which may cause trees to be felled in storms (Somers et al 2008). Eradication of the existing bittersweet at the farm may be feasible, but there are large nearby sources of bittersweet outside property boundaries. Since seeds are readily dispersed by birds, it is likely that new infestations will continue to occur.

Management in 2012-2017: No bittersweet vines were treated at Squam Farm during this time frame.

Future Management & Monitoring: Only two patches of Oriental bittersweet vine were identified in the survey, just outside the 50’ wetland buffers, located along the edges of managed uplands/trails (Figure 17). Stems will be cut and stump treated with the standard technique using Aquamaster ® or Rodeo ® herbicide in the summer of 2018 if scheduling permits. Additional small vines may not have been visible in this survey, so any new populations encountered will be documented. We will record the locations of treated plants and estimate the area covered and height/length of vines in treated sites. We will GPS locations and take photos of treated areas to document pre- and post-treatment appearance.

Porcelain-berry (Ampelopsis glandulosa):

Risk Level: Porcelain-berry (formerly A. brevipedunculata) is highly likely to spread throughout the edge habitats at Squam Farm, where it appears to be replacing native fox grape (Vitis labrusca) (Figure 18). Porcelain-berry quickly blankets trees and shrubs with its vines and thrives in the moist soils, colonizing the edge habitat along trails and open fields (Swearingen et al 2010). A single vine can grow up to fifteen feet in one year, and the plants produce numerous fruit with long-lived seeds. Many additional small porcelain-berry and seedlings were observed near forest survey plots at Squam Farm in 2013-2016, leading us to believe that small individuals are scattered throughout the property as well as along pasture and trail edges, and will expand as gaps appear in the canopy. Eradication of this species from Squam Farm is not deemed feasible. Fruits are readily dispersed by birds, leading to serious ongoing colonization pressures from off-site seed sources. Large, well-established populations of this vine are found along nearby Squam Road and near Sesachacha Pond. Clip- and-drip treatment of large individual vines throughout the property does not appear feasible. It is difficult to locate all of the stems, and the plant is not easily uprooted, so manual removal is not feasible. Our management goal is to reduce cover of porcelain-berry and adjust management activities to minimize its spread if possible.

Management in 2012-2017: No porcelain-berry was treated at Squam Farm during this time frame. This species appeared to expand following the prescribed grazing implemented in the former Invasive Species Management Pasture, where vines ascended the remaining shrubs and covered their canopy with heavily fruiting vines above the sheep browse level.

Future Management & Monitoring: Manual methods such as mowing and/or herbicide will be required to suppress re-growth of porcelain-berry vines in the Invasive Species Management Pasture, and we are not likely to have the capability to tackle such a large task. Currently maintained trail and pasture edges may be brush cut/mowed prior to fruit ripening (before mid-August) to reduce spread of this species. However, porcelain- berry appears to be spreading rapidly along trails, field edges, and in forest gaps throughout the property. Large isolated vines may be cut and treated if time permits, but the infestation at Squam Farm is likely too large and pervasive to treat effectively at this time, with ample nearby seed sources outside the property boundaries.

Tree–of-Heaven (Ailanthus altissima)

Risk Level: Tree-of-heaven is a prolific and fast growing tree species and can colonize forest gaps as well as disturbed areas, posing a serious risk for spread at Squam Farm (Knapp & Canham 2000; Lawrence et al. 1991; Somers et al. 2008). The single tree documented at Squam Farm in 2008 had the potential to colonize the surrounding fields, which are not regularly mowed or grazed. The prognosis for eradicating this species at Squam Farm is good because the single individual located was treated in 2013, but vigorous re-sprouting in 17

2015 required follow-up spraying (Figure 19). Re-invasion potential is low, since the seed of this species is not bird dispersed and there are no large populations nearby.

Management in 2013-2017: Property Maintenance Staff cut the single tree with a chainsaw and notched the bark around its stump to increase herbicide treatment surface area, on September 20, 2013. We immediately applied 50% Aquamaster ® solution (25% concentration of the active ingredient, glyphosate) to the cut areas using a sponge. We returned to the site on August 11, 2014 and photographed and treated the 1 m tall single re- sprout that emerged using the cut-and-sponge method. Upon re-checking the site in early summer of 2015, we found that there were a number of new re-sprouts, which were likely present the year before but hidden under taller vegetation. These were scattered around the original cut stump in a 15 m radius and most were 0.5-0.75 m tall. We treated these with the hand pump sprayer using 3% Renovate 3 ® solution according to Best Management Practices on August 24, 2015 (Figure 19). Re-sprouts were noted in 2016, but no treatment took place due to scheduling constraints. On August 28, 2017, we returned to the site and cut and stump painted 10 root re-sprouts, ranging from 1-2 m tall.

Future Management & Monitoring: We will return to the site in August of 2018 to evaluate growth of re- sprouts, and will spray any re-sprouts with Renovate 3 ® in July-September as scheduling permits. Follow-up management and monitoring of this site will be required for at least 3 years with no live re-sprouts to ensure complete treatment. As demonstrated in 2015-2017, this species has continued to re-sprout vigorously from roots, so carefully checking a 20 m radius surrounding the cut stump will be necessary. We will GPS the locations of new sprouts if any are found outside the original area in 2018.

Weeping Lovegrass (Eragrostis curvula)

Risk Level: Weeping lovegrass is listed as invasive in eight states and by several parks and resource management entities (Anonymous 2006, 2012). Areas adjacent to the existing Squam Farm population and along the driveway edge are at the greatest risk of spread, and areas without disturbed soil that are farther from the infestation are less susceptible to colonization (Figure 20). However, seed has likely spread via mowing, as scattered clumps of this species have appeared at different areas within the former pastures at Squam. Weeping lovegrass is capable of out-competing native grasses and poses a threat to a number of state listed rare or endangered species present in nearby fields. Originally planted as an ornamental in the landscaping near the driveway, lovegrass has since expanded substantially along the driveway and into the adjacent grasslands. Re- routing of the driveway in 2011 created additional disturbed soil sites for this species to spread, which it did very quickly. While we added seed of native little bluestem to this area in 2011, weeping lovegrass seeds

established faster and out-competed the native grasses. When initially mapped in 2011, weeping lovegrass covered approximately 293 m2, which increased to 2014 approximately 704 m2 by 2014 (Figure 20).

Management and Monitoring in 2012-2017: We did not treat any weeping lovegrass at Squam Farm in 2012- 2013. In 2014-2015 we assessed the rapidly expanding new population along the re-routed driveway and removed the seed heads to reduce chance of spread to adjacent pastures. Small isolated plants were removed to test digging as a method of treating small clumps. We documented the expanding area of weeping lovegrass near the driveway with a GPS unit in 2014 and established two 50 m monitoring transects to collect pre- treatment pole intercept vegetation data. Prior to treatment (both herbicide and mowing) we cut seed heads to try to limit spread via seed. The weeping lovegrass in this area had been mowed in early summer but had re- grown vigorously by the end of July. In 2015 we mowed and then treated the area on the southeast side of the driveway using a backpack sprayer to apply 1.5% Rodeo ® with Cide Kick II ® adjuvant and Hi Light ® blue marking dye. There is some evidence that mowing lovegrass at a very short height just before the first frost in the fall will lead to winter-kill of this species [USDA-USFS] so we mowed late in the season in the area north of the driveway in hopes that this would reduce the vigor of these patches to enhance future treatment efforts. Additionally, in order to more explicitly test the efficacy of late fall mowing, we reserved a small area of weeping lovegrass on the southeast side of the driveway that was mown but not sprayed with herbicide (Figure 20). We visually compared the results of fall mowing to sections that were treated with herbicide to evaluate the effectiveness of both methods; herbicide treatment was highly effective while fall mowing was minimally effective. No weeping lovegrass treatment took place in 2016. On October 18-23, 2017, we sprayed (as described above), prioritizing outlier plants, areas close to the house and along the driveway. Due to time constraints we were able to complete spraying of the westernmost patches along the driveway, more than 75% of the area requiring treatment, before temperatures dropped below effective levels for treating non-woody plants (Figure 20).

Future Management & Monitoring: In 2018, we plan to treat all known patches with pump spray as described above. This method proved highly effective and less likely to stimulate weed seed bank germination through soil disturbance. The rapid spread of this species has made it a pressing concern, and its management will be a high priority over the next few seasons. We will obtain pre- and post-treatment photos of areas to be managed. Treatment areas and new occurrences will be documented with a GPS unit, allowing us to track effectiveness of treatment and document new outlier populations as they appear. Removal of the road edge fence posts improved our ability to mow, but the coordination of mowing and herbicide treatments during the summer months proved difficult due to residents present in the house. Herbicide treatment was postponed until after mid-October when the seasonal tenants moved out, and it was only due to a mild and relatively non-windy dry period that we were

able to complete a high percentage of the planned treatment. Obtaining permission to access these areas during late September through early October would be very helpful in managing this species effectively.

Plume Grass (Miscanthus sinensis and hybrids)

Risk Level: The plume grasses, or silver grasses, include about 50 cultivars of tall ornamental bunch grasses, some of which are very popular in landscaping on Nantucket. Japanese or Chinese silvergrass (Miscanthus sinensis) is listed as an invasive or potential invasive species in southern forests (Miller et al. 2006) and is listed as potentially invasive in Connecticut. Plume grass (Miscanthus sacchariflorus) and a hybrid called Miscanthus x giganteus, which is a hybrid cross of M. sacchariflorus and M. sinensis, were added to the Massachusetts Prohibited Plants list in recent years [MASSGOV]. Miscanthus sinensis is the species that we have observed spreading into minimally managed habitats on Nantucket. There was a planting of plume grass near the farm house and barn at the farm (Figure 3). We had not observed this species spreading beyond the landscaped area at the farm until 2015, when a few clumps were spotted along pasture edges, far from the established plantings. Since this plant appears to become established through landscape waste or windblown/waterborne seeds from the immediate area, if we remove the existing individuals, there is a high probability that we will be able to eradicate this species from Squam Farm.

Management and Monitoring in 2012-2017: In 2014 we documented the plume grasses near the house and along the fence in the farmyard using a GPS unit. We cut and removed flowering stalks in late fall to reduce risk of spread, and these were composted in the Nantucket Solid Waste facility’s digester. In 2015, we manually removed plants along the split rail fence near the barn and cut back the plants near the garden/walkway area along the eastern side of the house, prior to removal by Properties Maintenance staff during repairs to the parking area and garden. No treatment of Miscanthus took place in 2016. In 2017, we manually removed a large plant at the far end of the former lambing pasture by digging. No other plants were observed.

Future Management & Monitoring: In 2018, we will check pastures and trail edges in July-September for isolated Miscanthus, record their locations with a GPS unit, and treat them with digging. Root balls will need to be cut or broken into smaller portions and pre-composted prior to disposal, as Waste Options has informed us that they are above the compostable size and extra sand and soil must be removed because sand is abrasive and damaging to the digester.

Pasture Weeds:

Risk Level: We identified four weed species that had become widespread in heavily used pastures surrounding the permanent paddocks and around the house and barn at Squam Farm by 2011 (Figure 4). Creeping or Canada

thistle (Cirsium arvense) is considered either an invasive or a noxious weed in 33 states; bull thistle (Cirsium vulgare) is a large spiny thistle which is listed as an invasive or noxious weed in 9 states; and clammy goosefoot (Dysphania pumilio, =Chenopodium pumilio) is an annual weed associated with sheep ranching that contains allelopathic chemicals and can be toxic to livestock [USDA]. Horsenettle or Carolina nightshade (Solanum carolinense) is a perennial that grows in large clonal patches. This species, which contains chemicals toxic to livestock and has extremely sharp thorns that deter browsing (Bassett and Munro 1986) is considered non- native in the northeast, although it is native to North America (Haines 2011).

Management 2011-2017: Our management initially focused on balancing ecological needs with the need to provide higher quality forage for sheep. An area within the permanent paddocks was tilled and seeded with a pasture grass mix in 2011. Following tilling, this area was temporarily overgrown with clammy goosefoot, crab grasses (Digitaria spp.), and Muhlenberg’s paspalum (Paspalum setaceum var. muhlenbergii), along with large numbers of mullein (Verbascum thapsus) and bull thistle. Germination of these weeds from the soil seed bank inhibited the establishment of the grass and clover seed mix. The area was mowed repeatedly in 2011-2012 to reduce weed cover and encourage growth of grasses and clover. Areas that had large infestations of horse nettle, Canada thistle, and bull thistle were mowed as necessary during 2011-2015 to prevent seed set, and many individuals were removed with hand digging as time allowed, with assistance of volunteers and Science and Stewardship staff. Locally collected seeds of several grass and forb species were added to bare areas in 2012- 2015 to restore degraded pastures. We identified the native hairgrass (Deschampsia flexuosa, =Avenella flexuosa) as an early (cool) season grass with palatable and nutritional forage. Researchers have found that this species grows and retains nutrients for livestock into late spring (Lunnan and Todnem 2011). While seeds of this native hairgrass are difficult to obtain commercially, there are extensive local seed sources of this species in the Serengeti along Milestone Road. We added seed from this source to an area of the Invasive Management Pasture in the spring of 2014 and 2015, excluding sheep within the seeded area using temporary fencing to allow the plants to establish (Figure 9). No pasture weed treatments took place in 2016, although annual dormant season mowing continued. In July-August of 2017, Properties Maintenance staff mowed patches of Canada thistle in the former permanent paddocks to reduce vigor, and on October 18-19, 2017, these patches were sprayed with a 3% solution of Renovate 3 ® mixed with Cide Kick II ® adjuvant and Hi Light ® blue marking dye.

Results: We photographed areas of pasture weed infestations in 2011 and 2013 (Figure 21). Repeated mowing reduced seed production of clammy goosefoot, allowing grasses and clover to become established. Weedy grass species such as the clammy goosefoot, paspalum and crabgrass were outcompeted by more desirable forage grass species in 2012-2015. Intensive digging and mowing of the perennial and biennial weed species gradually 21

reduced their numbers over time, and minimized spread to new areas, although we noticed some spot populations of horsenettle appearing in the St. Andrew’s cross field in 2014-2015 (Figure 22). Photos taken in the same general area show a remarkable change from dense tall stands of these weeds, to a grass and legume dominated pasture mix in most parts of the former paddocks (Figure 21). The diligence of the prior Sheep Grazing Project Technicians successfully promoted perennial grass and clover and reduced pasture weed stands. While these species enhanced forage for the sheep and minimized erosion and soil compaction problems, they are mainly non-native and did not contribute to improving native plant habitat. During 2014-2015 sheep were pastured in the St. Andrew’s cross field more frequently. In that area we observed a trend of increased soil disturbance, along with expanding areas with dense cover of weedy species (particularly aggressive non-native grasses) where the sheep were provisioned with supplemental hay. Some of these overgrown weedy areas appeared to negatively impact the patches of St. Andrew’s cross (Hypericum stragulum) growing in this area, where we were conducting a study on the potential impact of sheep grazing on this rare native plant. Data from this project will be analyzed and interpreted in the future. In 2017, site visits showed mixed results. Populations of bull thistle, horsenettle, and clammy goosefoot all declined dramatically. In contrast, populations of Canada or creeping thistle expanded, with the exception of the frequently mown area west of the house (Figure 22). Challenges with scheduling growing season mowing and herbicide treatment made it difficult to treat pasture weeds as planned. Obtaining permission to access these areas during late September through early October would be very helpful in managing this species more effectively.

Future Management & Monitoring: While the infested areas in the former permanent paddocks were greatly reduced through the combined efforts of the prior Sheep Grazing Project Technicians and Science & Stewardship Staff, continued management will be necessary to ensure that these weeds do not reestablish or spread to other fields. Seed and possibly transplants of appropriate grass and forb species may be used in the future to transition pastures toward grasslands dominated by native early successional species. We will need to adapt management to rely on mowing and re-map invasives and pasture weeds in 2018 to assess the current vegetation communities to determine whether additional management is required. Based on the results from the St. Andrew’s cross research project, adjustments to the mowing schedule may be needed to favor growth of native species over introduced pasture weeds.

New Weed Concerns:

Two new weed concerns, common mugwort or wormwood (Artemisia vulgaris) and lily-of-the-valley (Convallaria majalis) were assessed at Squam Farm in 2017 (Figures 23 and 24). While neither species is listed as an invasive in Massachusetts [MASSGOV, MIPAG] or on Nantucket, they have both been demonstrated to spread aggressively and may pose a risk to native plant communities at Squam Farm if allowed to proliferate. 22

Common mugwort (Artemisia vulgaris)

Risk Level: While not listed as an invasive or prohibited plant in Massachusetts, common mugwort, also called common wormwood, is naturalized in at least 39 U.S. states [EDDMapS]. Observed spreading rapidly in disturbed areas along road edges and in old fields, it has become a serious pest plant in gardens and is particularly well-adapted to Nantucket’s sandy soils. This species is very difficult to eradicate once it gains a foothold as it spreads vigorously via underground rhizomes. GPS documentation of common mugwort in November of 2017 at Squam Farm indicated a small population near the barn, covering an area of approximately 4 m2, and point locations with few stems along the driveway (Figure 23). Treating mugwort with herbicide at this early stage is the best approach to prevent it from becoming widespread. Without treatment, it is likely to expand along the driveway edge and into nearby fields. Once managed, re-colonization potential is low. This plant can be eradicated or kept at minimal levels if treated soon and if not reintroduced through soil or road grading.

Management Recommendations for 2018: We recommend treatment of known patches and any others that are encountered with herbicide (Rodeo ® mixed with Cide Kick II ® adjuvant) in July and August of 2018, with a second treatment in September or October if necessary. As noted above for pasture weeds and weeping lovegrass, this population is near the house, so securing permission to access the site during the growing season will facilitate treatment.

Future Management & Monitoring: Following treatment in 2018, we recommend revisiting the known populations in October of 2018 and July of 2019 for assessment, and adapting management as necessary.

Lily-of-the-Valley (Convallaria majalis)

Risk Level: Lily-of-the-valley was introduced as a perennial garden plant and has become established in at least 29 states and three Canadian provinces [USDA-PLANTS]. It spreads vigorously via rhizomes to form large patches when growing in moist, rich soil, with partial or dappled shade and may become invasive when it spreads from garden settings into natural areas (Swearingen and Bargeron, 2016). The main patch at Squam Farm was GPS documented in May of 2017 and encompassed 0.91 acres, with additional small satellite populations to the west indicating that it has spread from its original location at an old house site (Figure 24). Due to the size of this patch, it is unlikely that complete eradication of this species is possible without many years of effort. However, re-colonization from outside the property are low and with management, we should be able to reduce the population, minimizing negative impacts on native forest wildflowers and vernal pool habitat.

Management Recommendations for 2018: We recommend testing treatment of the satellites and main patch outside of wetland buffers in mid-May to early June of 2018, before other plants and trees are leafed out in the area (Figure 24). Rodeo ®with Cide Kick II ® adjuvant applied with a pump sprayer is suggested. By treating early in the season we will be able to target the lily-of-the valley and avoid impacting native plants, which have not yet fully leafed out. After evaluating the effectiveness of the treatment we may apply to the Nantucket Conservation Commission for permission to treat remaining lily-of-the valley within wetland buffers.

Future Management & Monitoring: Following treatment in 2018, we recommend revisiting the known populations in October of 2018 and July of 2019 for assessment, and adapting management as necessary. Surveying and treating additional satellite populations and GPS documenting patch and point locations will allow us to monitor and follow up effectively.

Literature Cited

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Moore, R. J. 1975. The biology of Canadian weeds: 13. Cirsium arvense (L.) Scop. Canadian Journal of Plant Science 55(4):1033-1048. [Radius] Source for Radius Garden NRG Pro Stainless Weeder. Available online: Accessed March 24, 2014. Rathfon, R. and K. Ruble. 2006. Herbicide treatments for controlling invasive bush honeysuckle in a mature hardwood forest in west-central Indiana. In: Proceedings of the 15th Central Hardwood Forest Conference; Eds: D.S. Buckley and W.K. Clatterbuck. USDA Forest Service Southern Research Station, Asheville, NC, USA. Seiger, L. 1991. Element stewardship abstract for Polygonum cuspidatum (Japanese knotweed, Mexican bamboo. The Nature Conservancy, Arlington, VA, USA. Silander, J., J.A., and D. M. Klepeis. 1999. The invasion ecology of Japanese barberry (Berberis thunbergii) in the New England landscape. Biological Invasions 1:189-201. Silvertown, J. and B. Smith. 1989. Germination and population structure of spear thistle Cirsium vulgare in relation to experimentally controlled sheep grazing. Oecologia 81: 369-373. Somers, P., K. Kramer, K. Lombard, and B. Brumback. 2008. A guide to invasive plants in Massachusetts, Second Edition. Massachusetts Division of Fisheries and Wildlife. Swain, P. C., and J. B. Kearsley. 2001. Classification of the Natural Communities of Massachusetts. Massachusetts Natural Heritage and Endangered Species Program, Division of Fisheries and Wildlife, West Boyleston, Massachusetts, USA. Swearingen, J., and C. Bargeron. 2016 Invasive Plant Atlas of the United States. University of Georgia Center for Invasive Species and Ecosystem Health. Available online at: < http://www.invasiveplantatlas.org/> Swearingen, J., B. Slattery, K. Reshetiloff, and S. Zwicker. 2010. Plant Invaders of Mid-Atlantic Natural Areas, 4th ed. National Park Service and U.S. Fish and Wildlife Service. Washington, DC., USA. TON (Town of Nantucket) Conservation Commission. 2013. Wetland Protection Regulations for Administering the Town Bylaw Chapter 136. Adopted February 1988, Revised July 2013. Massachusetts USA. TNC. 1998. Vegetation community map of Nantucket. Page GIS Data Layer. The Nature Conservancy. [USDA] 2012 United States Department of Agriculture Plant Hardiness Zone Map. Available online at: . Accessed March 19, 2012. [USDA-USFS Southeastern Region] 2014. Field Guide for Managing Lehmann and Weeping Lovegrasses in the Southwest. Document # TP-R3-16-21. [NHESP] 2008. Priority and Estimated Habitats Layer. Massachusetts Natural Heritage and Endangered Species Program, Massachusetts Division of Fisheries and Wildlife, West Boyleston, MA, USA. Available online: . Accessed March 20, 2012. Williams, S.C., J.S. Ward, T.E. Worthley, and K.C. Stafford III. 2009. Managing Japanese barberry (Ranunculales: Berberidaceae) infestations reduces blacklegged tick (Acari: Ixodidae) abundance and infection prevalence with Borrelia burgdorferi (Spirochaetales: Spirochaetaceae). Environmental Entomology 38(4): 977-984

TABLES AND FIGURES

Figure 1: Locator map of Squam Farm Nantucket Conservation Foundation property, Nantucket, Massachusetts.

Table 1: Table of invasive woody plant species at Squam Farm with management feasibility and prioritization.

Woody Invasive Species Management Recommendations Shrubs Vine s Trees

Squam Farm Japanese Autumn Bush Multiflora Oriental Porcelain- Tree-of- Invasive Species Barberry Olive Honeysuckle Privet Rose Bittersweet berry heaven Shrub (forest, Shrub Shrub Shrub Vine Vine Type (Habitat) field) Shrub (field) (field, edge) (forest, edge) (field, edge) (forest, edge) (forest, edge) Tree (field) Population Extent 2 sites Sparse Many sites Many sites 3-4 sites 2 sites Many sites 1 site Reduce Cover Reduce Cover Reduce Cover Goal at Squam Farm Eradication Eradication & Spread & Spread Eradication Eradication & Spread Eradication Risk Level High High High High High High High Moderate Herbicide; Herbicide; Weed Herbicide; Weed Wrench; Herbicide; Herbicide; Brush cut; Recommended Treatment Herbicide Wrench Graze Graze Graze Graze Graze Herbicide Treatment Feasibility Good Good Moderate Moderate Moderate Moderate Low Good Low- Re-colonization Pressures Moderate Moderate Moderate-High Moderate Moderate Moderate High Low

Within 50' wetland buffer Some Most Many Most Some Some Most None

Within 100' wetland buffer All Most Most Most All All Most All

Table 2: Table of invasive non-woody and pasture weed species at Squam Farm with management feasibility and prioritization.

Squam Farm Non-Woody Invasives & Pasture Weeds Management Recommendations Invasive Species & Weeds Grasse s Forbs Pasture Weeds Weeping Common Plume Japanese Cypress Lily-of-the- Canada Thistle Clammy Common Name Lovegrass Reed Grass Knotweed Spurge valley & Horsenettle Bull Thistle Goosefoot Forb Grass Forb Forb Forb Forb Forb Type (Habitat) Grass (field) Grass (field) (woodland, (wetland) (field/edge) (pasture/field) (pasture/field) (pasture/field) (pasture/field) wetland) Permanent Permanent Population Extent 1 site 2 sites Few sites 2 sites Few sites Few sites Few sites Paddocks Paddocks Reduce Cover Reduce Cover Reduce Cover & Reduce Cover Reduce Cover Goal at Squam Farm Eradication Eradication Eradication Eradication & Spread & Spread Spread & Spread & Spread Risk Level Moderate Moderate Moderate High High Moderate High High Low Herbicide, Herbicide; treat outliers Mow to prevent Recommended Herbicide in Cut & Cut & Change road and main Dig; Mow to Mow; Prevent Dig seed; Spray Treatment uplands Herbicide Herbicide grading upland area prevent seed Bare spots Patches method first to test methods. Treatment Feasibility Good Good Good Good Low Moderate Moderate Moderate Low Re-colonization Pressures Low Low Low Low High Low Low Low Low Within 50' wetland buffer Some+ Some None Some None Some None None Some Within 100' wetland buffer Some+ All None Some None Some None Some* Some* Some* = typically located in managed upland pastures.

Some + =Best Management Practices applied for management within wetland buffers.

Figure 2: Map depicting Squam Farm invasive plants documented in 2011 survey, with wetlands and 50’ wetland buffers.

Figure 3: Map depicting Squam Farm non-woody invasive plants documented 2011-2014, with wetlands and wetland buffers.

Figure 4: Map depicting Squam Farm pasture weeds in 2011 survey in permanent pastures and farmyard, with wetlands and 50’ wetland buffers.

Figure 5: Map depicting Squam Farm woody invasive plants with 100’ wetland buffers.

Figure 6: Map depicting Squam Farm invasive plants within 50’ wetland buffers.

Figure 7: Map depicting Squam Farm delineated wetlands with associated invasive plants.

Figure 8: Map depicting Squam Farm certified vernal pools and priority rare species habitat, with known locations of rare plant species.

Table 3: Table of rare and endangered species at Squam Farm.

Species Name Common Name Status

Plants: Hypericum stragulum St. Andrew’s Cross E Aristida purpurascens Purple Needlegrass T Crocanthemum dumosum Bushy Rockrose SC Liatris scariosa var. novae-angliae New England Blazing Star SC Sisyrinchium fuscatum Sandplain Blue-Eyed Grass SC Botrychium dissectum var. obliquum Cutleaf Grapefern Very rare, but not listed

Reptiles: Clemmys guttata Spotted Turtle Formerly SC

Moths: Bagisara rectifascia Straight Lined Mallow Moth SC Chaetaglaea certa Noctuid Moth SC Papaipema stemocelis Chain Fern Borer Moth E

Figure 9: Map depicting Squam Farm new invasive species management pasture, with planted areas.

Figure 10: Map of Squam Farm common reed management sites at pond and abandoned cinderblock foundation.

Figure 11: Top, pre-treatment (2011) photos of Squam Farm common reed at abandoned foundation site; bottom, map depicting changes in common reed patch area with treatment (2011-2017).

Figure 12: Invasive Management Pasture grazed in 2012-2015, area sown with little bluestem and planted with native grass and forb seedlings in summer and fall of 2014-2015; bottom photos showing re-vegetated area in 2017.

Figure 13: Barberry and burning bush at Squam Farm with treatment type (herbicide and manual); all known barberry and burning bush at Squam Farm were treated 2012-2017.

Figure 14: Bush honeysuckle treated with cut and prescribed grazing in 2014 (circled in yellow), treated with herbicide cut-and-sponge (circled in purple), and areas that may be targeted for treatment in 2018 (circled in pink).

Figure 15: Squam Farm areas of multiflora rose that may be targeted for treatment in 2018 (circled in red).

Figure 16: Squam Farm privet treatment areas: yellow circled areas were treated in 2014, and pink circled areas that may be targeted in 2018.

Figure 17: Squam Farm areas of bittersweet that may be targeted for treatment in 2018 circled in pink.

Figure 18: Squam Farm porcelain-berry treatment areas that may be targeted for 2018 circled in pink.

Figure 19: Squam Farm location of tree of heaven originally treated in 2013, and point locations with re-sprouts treated in 2015 and 2017.

Figure 20: Top Map: Distribution of Squam Farm weeping lovegrass populations, depicting treated (orange) and untreated patches (green) in 2017. Bottom map: Close-up of Squam Farm driveway area lovegrass populations, treated in 2015 with mowing (yellow cross-hatch); treated in 2015 with mowing and herbicide (white cross-hatch); 2017 follow-up treatment with herbicide (orange).

Figure 21: Squam Farm permanent paddock area with pasture weed infestations at start of intensive pasture weed management program in 2011 (top photos) and after intensive pasture weed management in 2013 (bottom photos).

Figure 22: Squam Farm former permanent paddocks pasture weed areas in 2014 (top map), and in 2017 (bottom map); refer to Figure 4 for original extent of pasture weed infestations).

Figure 23: Squam Farm newly mapped common mugwort (Artemisia vulgaris) populations near house and along driveway in the fall of 2017.

Figure 24: Squam Farm newly mapped lily-of-the-valley populations, depicting main patch and satellite populations near the driveway in the spring of 2017.