Vol. 27 No. 3 Long Island Botanical Society The Quarterly Newsletter Summer 2017 The Hardy Kiwi (Actinidia arguta) Eradication Project At Coffin Woods Preserve, Locust Valley, NY By Allan J. Lindberg ajlindberg@optonline.net Introduction In December 2013, the North Shore Wildlife Sanctuary (NSWS), along with its partners the Long Island Botanical Society and Portledge School, was awarded a grant by the Long Island Invasive Species Management Area (LIISMA) to eradicate an approximately 2000-square-m population of hardy kiwi ( Actinidia arguta). This species has been classified by LIISMA as an “early response” invader: plant species that have fewer than five infestations in the area. This designation increases the likelihood that localized invasive populations will be found, contained, and eliminated before they become widely established. Project field work began in November 2014. The physical eradication of the Actinidia was accomplished in early May 2015. Site monitoring for regrowth of Actinidia and its removal began in late May 2015 and continued through mid-June 2016. Site Description The area targeted for eradication is a small, less-than-half-acre section of Coffin Woods Preserve, a 73-acre preserve, part of the North Shore Wildlife Sanctuary system in the Village of Matinecock, Nassau County, New York (Fig. 1). This mature forest, with towering tulip poplar (.Liriodendron), oaks ( Quercus sp.), and beech ( Fagus sp.) trees, also includes some shagbark hickories {Carya ovata ) and one of the largest butternut {Juglans cinerea) trees on Long Island. A rare population of Euonymus americana (American strawberry-bush) occurs there, as well as a vigorous population of Dendrolycop odium obscurum (flat- branched tree-clubmoss), hundreds of Trillium erectum (red trillium) and Erythronium americanum (yellow trout-lily), and several species of ferns. The predominant ecological community is an oak- tulip tree forest. The preserve is bounded on the north by Long Island Railroad tracks, just south of Oyster Bay Road. The southern boundary is the Portledge School campus, and the east and west boundaries have private residences. Publicity and Recruitment of Monitoring Volunteers A one-page article announcing the grant was published in the Winter 2014 edition of the LIBS newsletter (Quart. Newslett. Long Island Bot. Soc. 24:2). Four volunteers were recruited to monitor any regrowth of the Actinidia and remove other invasives as needed. Just prior to the physical work, informational signs were posted at the site, notifying the public of the “Invasive Species Control Project,” the species being controlled, and the partners sponsoring the project. (Continued on page 19) Figure 1. Actinidia arguta infested site as it appeared in 2014, vines covering trees and ground. [Photo by L. Lindberg.] Page 18 Long Island Botanical Society Vol. 21 No. 3 Long Island Botanical Society Founded: 1986 • Incorporated: 1989 The Long Island Botanical Society is dedicated to the promotion of field botany and a greater understanding of the plants that grow wild on Long Island, New York. Visit the Society’s Web site www.libotanical.org Executive Board President Eric Lamont 631-722-5542 elamont@optonline.net Vice President Andrew Greller agreller2@optonline.net Treasurer Carol Johnston johnljohnston2@optonline.net Recording Secretary Sue Avery suea483@gmail.com Corresponding Secretary Rich Kelly vze2dxmil@verizon.net Committee Chairpersons Flora Eric Lamont elamont@optonline.net Andrew Greller agreller2@optonline.net Field Trips Allan Lindberg ajlindberg@optonline.net Programs Rich Kellyvze2dxmil@verizon.net Membership Lois Lindberg lalindberg3@optonline.net Conservation Bill Titus btitus@optonline.net John Turner redknot2@verizon.net Education MaryLaura Lamont woodpink59@gmail.com Hospitality Kathleen Gaffney kg73@cornell.edu Dorothy Titus btitus@optonline.net Newsletter Editor Margaret Conover margaret.conover@gmail.com with special thanks to Skip & Jane Blanchard Webmaster Donald House libsweb@yahoo.com Society News LIBS receives grant from Biodiversity Books, Inc. In March 2017, LIBS Treasurer Carol Johnston received a letter saying, in part: “We are pleased to enclose for Long Island Botanical Society an unrestricted one-time grant of $500 from Biodiversity Books, Inc. at the recommendation of its President Mr. Guy A. Tudor. . . . Keep up the good work!” LIBS sincerely appreciates this grant! What a nice surprise. Thank you Guy! Traveling Exhibition of Native Plant Drawings. At the May 2017 LIBS meeting, Diane Bouchier presented an excellent program on “Botanical Art: Tradition and Revival.” Working in cooperation with the Long Island Native Plant Initiative, Diane has created a series of colored pencil drawings of Long Island native plants that will be on exhibit from June to August 2017 at Sweetbriar Nature Center in Smithtown, and in September and October at Seatuck Environmental Association, Scully Mansion in Islip. The goal of the exhibition is to make the public more aware of the subtle beauty of these plants that are so essential for our pollinators. LIBS is acknowledged by East Hampton Garden Club. LIBS has been working with other groups for the past 30 years trying to save populations of native orchids on the South Fork. At Barnes Hole in East Hampton Township, several groups are currently working to save New York States last known population of the yellow fringed orchid, Platanthera ciliaris. Julie Sakellariadis and the East Hampton Garden Club have been coordinating the effort and they were recently honored with the Native Plant Conservation Award, presented by the New York Flora Association, for the effort to preserve P. ciliaris. In accepting the award, Julie wrote: “I’m stunned and thrilled, and especially want to thank the many wonderful partners and advisers who share the glory of this award with us: the Town of East Hampton, the East Hampton Highway Department, the South Fork Natural History Museum, the Broadview Property Owners' Association, The Nature Conservancy, Saskas Surveying Co., Long Island Botanical Society and the New York Botanical Garden.” “Atlas of the Flora of Long Island, New York” by the LIBS Flora Committee has been accepted for publication by the Torrey Botanical Society and will be published as volume 30 of Memoirs of the Torrey Botanical Society . Printing is planned for 2019. LIBS member Larry Liddle has moved to Santa Barbara, California and he will be dearly missed. Larry has been an active member of LIBS for many years leading field trips, writing articles for the newsletter, presenting programs, and regularly attending monthly meetings. Larry participated in the LIBS 30 year anniversary trip to the Sierra Nevada in California. Thank you Larry, for your service to LIBS, and keep in touch. Eric Lamont and Mike Feder published in June 2017: “ Eupatorium capillifolium (Asteraceae) new to New York” in Phytoneuron (2017-43: 1-4). [Abstract: Eupatorium capillifolium , dog fennel, is reported new to the flora of New York based on a 2015 collection from eastern Long Island, Suffolk County, and observations from 2013 to 2017.] Long Island Botanical Society Vol. 27 No. 3 Page 19 (Hardy Kiwi continuedfrom cover) Figure 2. Heavy equipment used by the landscape contractor to clear the site to bare ground. [Photo by C. Johnston, 4/14/15.] In addition, an article entitled “ Invasive Hardy Kiwi at Coffin Woods ” written by LIBS member Dan Kriesberg, one of the project’s volunteers, appeared in the “Locust Valley Leader.” Pre-removal Plant Inventories Plant inventories carried out by a group of students from Portledge School supplied information on the species occurring in the Actinidia-'mfested site as well as an adjacent control site. The infested and control sites were in close proximity and had the same degree of forest cover. Two belt transects were run through each site. revealed many downed Liriodendron (tulip poplar) trunks of 1 m diameter and several large surface boulders. These were moved to the site perimeter to effectively finish the remainder of the work. An excavator then carefully scraped the entire site to a depth of 5 to 50 cm, removing a majority of the surface vegetation below the root zone (Fig. 2). The debris was loaded into dumpsters, and removed from the preserve for disposal. The site was then given a rough grading with the excavator, followed by final grading using a tractor rake (Fig. 3). Initial observations indicated that the Actinidia was effectively removed from 95 percent of the site, with sprouts regenerating primarily from the area at the trail/removal site interface. Shallow removals (5 cm) had been done at the trail interface to avoid damaging the preserve trail system. In areas of removal deeper than 15 cm, the Actinidia seems to have been successfully removed. Post-Removal Site Monitoring Prior to site monitoring, eight permanent 2-square-m quadrats were installed and marked with stake flags. Surveys conducted by volunteers from the Long Island Botanical Society started on May 28, 2015 and continued at 2- to 3-week intervals through the end of the growing season (Fig. 4). A final inspection was done on June 6, 2016. On each survey day, a general random inventory was first conducted throughout the cleared site, changing the route each time to ensure site coverage. Once the random walk-through was completed, each of the eight quadrats was examined for percent plant cover and species present. Plants were then listed in a database of plant species (Continued on page 20) The Actinidia- infested site was densely overgrown with another non-native, Akebia (five-leaf), and with Toxicodendron (poison ivy). At that site both belt transects were run along the trail edge in order to limit the students’ exposure to poison ivy and other harmful plants. The control site lacks poison ivy and is more typical of a forest shrub layer, so one belt transect was located along the trail edge, and the second from the trail into the center of the control site. Physical Removal of the Actinidia Population The physical removal of the Actinidia population was done with equipment well- suited to the requirements of the removal. The pre-removal mowing of the infested site Figure 3. Site after work was completed. Information sign is posted on trees. [Photo by L. Lindberg, 5/13/15.] Page 20 Long Island Botanical Society Vol. 27 No. 3 (Hardy Kiwi continued from page 19) Figure 4. Long Island Botanical Society volunteer researchers (I to r): Bill Titus, Andy Greller, Project Coordinator Al Lindberg. [Photo by L. Lindberg, 7/8/15.] found at the site. When Actinidia regrowth was located, each plant was numbered and flagged for eradication, and photographed. As expected, these surveys mostly revealed plant species that had previously occurred in the removal site or within Coffin Woods. Species uncommon in the preserve but new to the site were non-natives Paulownia tomentosa (princess-tree) and Catalpa speciosa (northern catalpa); entirely new to the preserve is Macleaya cordata (plume-poppy) which appeared as several seedlings in the cleared ground. It is possible that the Macleaya was brought in with the removal equipment. However, given Coffin Woods’ estate history, it is more likely that the species occurred at the site during the estate period, its seeds remaining in the soil seed bank. Eradication of Actinidia Regrowth In general, the Actinidia regrowth was in the form of small vining plants that could be traced back to a fragmented root, or in a location that couldn’t be gotten into by the excavator. A total of 37 re-sprouts were located. Each individual plant was treated with Roundup™ herbicide. The plants responded well to the herbicide treatment; no reapplication was needed, and the plants were dead to the roots within ten days. These plants remained flagged through the winter of 2015-2016, and when checked the following spring, there was no sign of re-sprouting. One newly re-sprouted plant was found during the June 2016 survey, suggesting that a rootstock could have remained dormant in the soil for at least a year following the eradication. Fortunately, this population appears to have consisted of all male plants. During the entire survey no female flowers, fruit, or obvious germination of plants from seed were observed. Summary Although the eradication of the hardy kiwi population at Coffin Woods has been very successful, there is no way to guarantee that we have removed all the Actinidia. Finding a freshly sprouted Actinidia during our final survey suggests that there are probably root fragments that could re-grow at the site for years to come. Therefore, the site should be re-checked several times a season for the next three to five years. If re-sprouting plants are found, they should be treated and/or removed. At this point, the eradication site is recovering quite nicely, and about 85% of the site is totally revegetated (Fig. 5). During the growing season, the cover in many sections has become quite dense, dominated by Rubus sp. (blackberry) shrubs and Phytolacca (pokeweed), often reaching seven feet tall. Normally this would be desirable, but in this study site, the cover should be kept low and workable to adequately monitor and control re-invading Actinidia. Ideally, the area should be mowed periodically, not only to keep the site manageable but to help in controlling other invasives that inhabit the site. Our method of eliminating and monitoring the Actinidia worked well. However, the question remains, is this the best way to control a population of Actinidia arguta?. While one would ideally use only physical removal, the combination of physical and chemical control was undoubtedly more Figure 5. Vegetation recovery at site, July 2016. [Photo by L. Lindberg.] Long Island Botanical Society Vol. 27 No. 3 Page 21 effective. We did our physical control first, opening the site with heavy equipment, removing the material and following up with monitoring, using chemical control as a backup. Unfortunately, this left a good number of rootstocks to re-sprout. A better method may have been to first locate, cut and apply herbicide to major vines before the physical removal, giving the vines enough time to die to the roots. Subsequent monitoring could then indicate a back-up chemical control where needed. Observing the re-vegetation of a site stripped to mineral soil was an educational experience for us all. As the vegetation returned, we quickly learned what the soil seed bank had to offer. Each survey was truly an interesting walk-through, documenting which species re-populated the site, which ones were new, and puzzling over “mystery plants” to identify. Our surveys also revealed that the Actinidia had not been totally eliminated, and gave us the opportunity control what remained. Overall, the methods used during the project—removal, pre- and post-removal monitoring, eradication and post¬ eradication follow-up—all worked well. With a little fine tuning, our methods could be suitably used by other groups in future hardy kiwi eradication projects. Acknowledgments The Coffin Woods Hardy Kiwi Actinidia arguta Eradication Project has been accomplished by a partnership of organizations. In particular, I would like to thank Steve Young of NYSDEC and LIISMA for his help and guidance; Carolyn Chiu and the Advanced Placement Biology Class of Portledge School for their work on the initial plant surveys; Andy Greller, Dan Kriesberg, Lois Lindberg and Bill Titus of LIBS for their excellent botanical work on the post-removal plant surveys; and finally, Carol Johnston and Tom Hornosky of NSWS for their photography and support throughout the project. juno, aas-Timo wind opO“fr^ frP ar, ‘ only 4H cn^***^ *>?***'**' ******** j, KwMtfceitib ”, _ * and naV"’ a* n f an t-xajjcB ?-.-■■■' * 3j Wlmi r ° t ‘ T ' - ftbrryn* root, * w»P 1 ’ , u.s.prH' In wortl* or drawing* of,, * . 3 * Ar V -.,.1 r-wirM t«brw taboroUff) wol*.. *.* L T}i>LiA.gttnh IttLvm uldur* Mid . s tiw pr^ ^ “"•—7.;;. I margin..- •■■■■ TC,' ' *Tkc. and nnbel. 14. Wbal art iwwtw . . ^ * K WW » 'V H*-V**-“ A MTWta * • !' v >’"" c AmoriMnn^ ™S?VU. ««."«*. you »" a >**- p 0 k k or fl *>™S£; D| 'itbrAiilJ