Does Suburban Horticulture Influence Plant Invasions in a Remnant Natural Area? Author(s): Elena S. Tartaglia, Myla F.J. Aronson and Jordan Raphael Source: Natural Areas Journal, 38(4):259-267. Published By: Natural Areas Association https://doi.org/10.3375/043.038.0406 URL: http://www.bioone.org/doi/full/10.3375/043.038.0406
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BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. R E S E A R C H A R T I C L E ABSTRACT: The horticultural trade is a well-known source of nonnative invasive plant species, yet urban and suburban developments are routinely planted with these species, creating high invasion pressure on adjacent natural areas. Understanding the spread of nonnative species and predicting invasions is critical • for the management of natural habitats. Here, we examine the similarities in nonnative plant community composition between a remnant natural habitat at Fire Island National Seashore and the surrounding residential communities to assess the impact of nonnative invasive horticultural species on the natural Does Suburban area. In the natural area, we identified 16 locally listed invasive plant species. In residential areas we identified 21 locally listed invasive species. Of 162 properties surveyed, 144 appeared to be occupied Horticulture and maintained by residents; 18 appeared unmaintained or abandoned. Unmaintained properties had significantly more invasive species than maintained properties. Nonnative species composition between the natural and residential areas was not significantly different. In the natural area, distance from subur- Influence Plant ban edge, native species richness, and soil moisture were important drivers of invasion. We show that in this particular natural area, invasive plants have not invaded farther than 25 m into the forest, indicating Invasions in a the strong role of edge effects in invasions. Additionally, we show that unmaintained properties in the residential areas may be the primary source of invasives to natural area. Homeowner education on the impacts of invasive species and active management of the nonnative invasive species in the unmaintained Remnant Natural properties may be important for preventing further invasions to the forest. Area? Index terms: edge effects, Fire Island National Seashore, homogenization, invasive plants, wildland– urban interface Elena S. Tartaglia1,4 1 Department of Biology and INTRODUCTION ichard 1997; Reichard and White 2001), Horticulture particularly for ornamental species (La Bergen Community College Nonnative invasive plant species may Sorte et al. 2014). Anthropogenic landscape 400 Paramus Road disrupt the ecological services of native change, including human development and Paramus, NJ 07652 ecosystems (Gordon 1998; Dukes and fragmentation of natural habitats at the re- Mooney 2004), change the composition gional scale, is tied to invasions in a variety of native habitats (Hejda et al. 2009), and of ways including facilitating dispersal and 2 Myla F.J. Aronson cause declines in populations of native spe- establishment via roads, edge habitats, Jordan Raphael3 cies (Clavero and Garcia-Berthou 2005). and changes in stream hydrology (von der Nonnative invasive species also represent Lippe and Kowarik 2008; Gavier-Pizarro an economic threat with estimated losses et al. 2010). Urbanization, in particular, 2 Department of Ecology, Evolution of up to 120 billion USD per year, of causes the decline of native species con- and Natural Resources which nonnative invasive plants account current with the establishment of nonnative Rutgers, The State University of for 25 billion USD (Pimentel et al. 2005). species (e.g., McKinney 2006; Aronson et New Jersey As the number of plant species introduced al. 2015). At the local scale, management 14 College Farm Road accidentally or deliberately via horticulture decisions by homeowners influence species New Brunswick, NJ 08901 increases, the rate of invasions is also composition, often in favor of nonnative expected to increase (Westbrooks 2004; ornamental species (Cubino et al. 2015). 3 Fire Island National Seashore Gavier-Pizarro et al. 2010). As a result, it U.S. National Park Service is predicted that biodiversity in communi- Natural areas in urban and suburban 120 Laurel St. ties currently dominated by native species landscapes are at high risk for invasion Patchogue, NY 11772 will decrease as they become invaded by by the many nonnative species continually a few globally common nonnative species introduced in the yards and gardens of the • (Rooney et al. 2004; McKinney 2006). adjacent residential neighborhood (Stewart This process of biotic homogenization, et al. 2007; Hanspach et al. 2008; Cubi- 4 Corresponding author: or the simplification of biota via species no et al. 2015). Suburban developments [email protected]; (973) 865-7390 introduction, threatens the natural history are routinely planted with a variety of identity of wild protected areas (National both native and nonnative ornamental Park Service 2010). species and this invasion risk is expected to increase with increasing horticultural Invasions of nonnative plants are closely introductions and climate change (West- Associate editor: Chris Evans tied to human activities at global, regional, brooks 2004). Nonnative plant species are and local scales. The global horticultural planted in high abundances in residential Natural Areas Journal 38:259–267 trade is well known to be the primary source developments, thus there could be high of invasive plant species introductions (Re- propagule pressure of these species on
Volume 38 (4), 2018 Natural Areas Journal 259 adjacent natural areas. Most research on Mastic Beach, New York, USA (Figure 1). identified all native and nonnative trees, wildland–urban interfaces has focused on The WFE lies within a newly recognized shrubs, and ground vegetation and mea- wildfire risks (see Radeloff et al. 2005), biodiversity hotspot, the North American sured soil pH, soil moisture, canopy cover, however the way that human settlements Coastal Plain (Noss et al. 2015; CEPF and light availability. We estimated percent affect neighboring ecosystems through 2016). The town of Mastic Beach has a cover of each nonnative species present in invasive species introduction warrants population of 7464 people. The estate is the plot as well as estimating total percent further examination. The influences of surrounded on three sides by moderately cover of all native plant species in the urban and suburban settlements on natural dense suburban housing (~375 single fam- plot (combined) and percent cover of the areas range from obvious destruction and ily houses/km2) and serves as a refugium dominant understory native species. We fragmentation of habitats to the less easily for diverse plant and wildlife species. The also identified canopy species present in observed results of these processes, such northern long-eared bat or northern myotis or overhanging the plots. as increased propagule pressure of invasive (Myotis septentrionalis Troue.), a federally species and edge effects (Bar-Massada et threatened species, can be found at the We measured soil pH with a FieldScout al. 2014). WFE. Additionally, a pair of bald eagles pH 110 meter (Spectrum Technologies, (Haliaeetus leucocephalus L.) has nested Plainfield, IL) at four random locations In the United States, there are approx- within the boundaries of the reserve since within each plot. To measure soil pH, we imately 4000 nonnative plant species 2014. The WFE is the former plantation scraped aside leaf litter and sampled soil that have spontaneously established in and home of William Floyd, one of the to 5-cm depth. We used equal parts soil natural habitats. Of these, one-fourth are original signers of the US Constitution. The and distilled water to create a slurry and considered threats to native plant and an- WFE has been part of Fire Island National measured the pH of the slurry. We also imal communities (Sullivan et al. 2005; Seashore since 1965 and includes 248 ha of measured soil moisture with a FieldScout National Park Service 2010). Examples secondary forest, some of which was never TDR 100 soil moisture meter (Spectrum of such plant species in the northeastern farmed. The forested areas are dominated Technologies) at four random locations United States include Japanese barberry by coastal oak–heath forest and by pitch within each plot. We measured light avail- (Berberis thunbergii DC.), Oriental bitter- pine–oak forest, maritime deciduous scrub ability in the understory at the center and sweet (Celastrus orbiculatus Thunb.), and forest, and acidic red maple basin swamp two random locations within each plot Japanese honeysuckle (Lonicera japonica forest (red maple–black gum dominant) using a LI-COR light meter and line quan- Thunb.). In the New York metropolitan (Klopfer et al. 2002). The surveyed areas tum sensor (LI-COR 250A and 191SA; area, plant invasions by these species cause in this study were primarily within the pitch LI-COR Biosciences, Lincoln, NE). We the decline of native species biodiversity pine–oak forest type, which is approxi- collected all light availability data on the and are actively managed by many natural mately 80–100 y old and is managed as a same uniformly sunny day between 10:00 areas land managers. However, these and natural area currently by the US National AM and 2:00 PM. other known invasive plants continue to Park Service. This community is dominated be sold in local and national nurseries by native species composed of a canopy Residential Area Surveys (Burt et al. 2007). Here, we examine the including Quercus alba L., Quercus rubra influence of invasive horticultural plantings L., Carya spp., Sassafras albidum Nutt., We conducted residential vegetation sur- and spontaneous invasive populations in Prunus serotina Ehrh., and Acer rubrum veys also during June 2014 in neighbor- suburban housing developments on the L., with Pinus rigida Mill. interspersed hoods on streets immediately surrounding structure of plant invasions in the natural intermittently (Clark 1986). The shrub the WFE, running along the same compass areas of the William Floyd Estate, Mastic layer is dominated by Gaylussacia bacca- bearing as the transects within the natural Beach, New York. We hypothesized that ta Wangenh., except for a few low-lying area. We visually identified the presence suburban plants are important sources of wet areas dominated by Clethra alnifolia of targeted invasive nonnative species in invasions to natural areas. Understanding L. While the forested areas are primarily residential front and side yards on both the role of yard floras on plant invasions dominated by native species, there is high sides of the street occurring within 300 in natural areas will provide a basis for risk of further invasion by existing and m of the border of the estate (Figure 1). suburban garden management practices new horticultural species introductions in Targeted invasive nonnative species were that incorporate native plant biodiversity. the bordering residential neighborhoods. defined from two sources: (1) those non- native invasive species found in the natural METHODS Natural Area Surveys area surveys, and (2) nonnative invasive species listed by the Long Island Invasive Study Area We established nine 100-m transects in Species Management Area (LIISMA). forested areas in the north and west regions LIISMA is a partnership of government The William Floyd Estate (WFE), 40°46′N, of the WFE. We established six 5 × 5-m agencies, nonprofit organizations, and 72°49′W, is part of the Fire Island Na- plots along each transect (Figure 1) for private businesses and coordinates inva- tional Seashore located on Long Island in a total of 54 plots. Within each plot, we sive species management and education
260 Natural Areas Journal Volume 38 (4), 2018 Figure 1. Location of natural area surveys within and residential area surveys surrounding the William Floyd Estate (WFE), Mastic Beach, New York.
across the region (LIISMA 2016). In Data Analyses tionship between the richness and cover of 2008, LIISMA designed a protocol for nonnative species and local environmental assessing the invasiveness of nonnative We compared the community composition variables (distance from edge in meters, plant species found in the region (LIISMA (presence/absence) of all nonnative species soil pH, soil moisture, light availability, 2016). The protocol ranks nonnative plant found in the natural area and the residential native plant cover) within the WFE (JMP area (24 species) using nonmetric multidi- species invasive threat levels from Low Pro 11.2.0). mensional scaling (NMDS) and multiple to Very High. These rankings are based response permutation procedure (MRPP). RESULTS on several criteria, including ecological We used t tests to assess the difference impact, biological characteristics, dispersal in nonnative invasive species richness ability, ecological amplitude, distribution, between the occupied and unoccupied Natural Area and Residential Surveys difficulty to control, and status of cultivars/ residential units (JMP Pro 11.2.0; SAS hybrids. Institute, Cary, NC). We used stepwise We found 46 native, 15 targeted LIIS- multiple linear regression to assess the rela- MA-listed nonnative invasive, and 4 non-
Volume 38 (4), 2018 Natural Areas Journal 261 native plant species not listed present in evident landscaping maintenance, presence C. orbiculatus are ranked by LIISMA as the natural area (Table 1, Appendix 1). In of vehicles, and/or visible occupants) while “very high” priority species and A. vulgaris all but four transects, nonnative species did 18 appeared unmaintained or abandoned is ranked as “high” priority. not penetrate more than 5 m into the forest (as determined by lack of evident land- from the fence line delineating the edge of scaping maintenance, boarded windows, Nonnative invasive species composition the estate. In all transects, nonnative species confirmation from neighbors, and/or were did not penetrate more than 25 m from the vacant lots). On average, occupied proper- was similar between the natural area and estate’s edge. The three most frequently ties contained 2.13±0.49 nonnative invasive the neighborhoods (Figure 2). There was occurring nonnative species in plots within LIISMA listed species. Unmaintained areas no separation of the natural area from the the WFE were Lonicera japonica (occur- contained significantly more nonnative in- residential nonnative plant communities ring in 20.4% of plots), Rosa multiflora vasive species than maintained properties, in NMDS ordination space (Axis 1: F = Thunb. (occurring in 13.0% of plots), and with an average of 5.89±0.16 nonnative 0.6121, P = 0.4462; Axis 2: F = 1.6751, P Celastrus orbiculatus (occurring in 7.4% species per property (t = 7.85, P < 0.01). = 0.2152). However, the residential com- of plots). All three of these species are munities were clustered closer in ordination ranked by LIISMA as “very high” priority The three most frequently occurring LIIS- space, indicating less variation among nonnative invasive plant species. MA-listed nonnative species in surveyed residential plant communities than in the residential areas were Acer platanoides natural communities. Residential nonnative In residential areas, we identified 24 LIIS- L. (occurring in 31.7% of surveyed prop- plant communities had significantly lower MA-listed nonnative invasive plant species erties), Artemisia vulgaris L. (occurring beta diversity (average Sorensen’s distance (Table 1). Of 162 properties surveyed, 144 in 31.1% of surveyed properties), and C. = 0.24) than the natural area (average appeared to be currently occupied and orbiculatus (occurring in 29.2% of sur- Sorensen’s distance = 0.69; MRPP, A = maintained by residents (as determined by veyed properties). Acer platanoides and 0.18, P < 0.0001).
Table 1. Nonnative invasive plant species found in the natural areas and residential areas and their invasive rank as assessed by Long Island Invasive Spe- cies Management Area (LIISMA). VH = very high invasiveness; H = high invasiveness; M = moderate invasiveness; L = low invasiveness; NR = not rated.
Species Residential Natural Area LIISMA rank Acer palmatum x xM Acer platanoides x x VH Albizia julibrissin x x VH Alliaria petiolata xL Ampelopsis brevipedunculata xH Aralia elata x x VH Artemisia vulgaris xxH Berberis thunbergii x x VH Celastrus orbiculatus x x VH Cornus kousa x x NR Elaeagnus umbellata x x VH Epipactis helleborine x x NR Euonymus alatus x VH Hedera helix xM Ligustrum vulgare xH Lonicera japonica x x VH Morus alba xM Phragmites australis x x VH Phyllostachys spp. x NR Robinia pseudoacacia x x VH Rosa multiflora x x VH Rubus phoenicolasius x VH Solanum dulcamara xM Wisteria spp. x x M
262 Natural Areas Journal Volume 38 (4), 2018 Figure 2. Nonmetric multidimensional scaling (NMDS) of nonnative invasive species composition between the natural areas (diamonds) and the neighborhoods (squares), William Floyd Estate, Mastic Beach, New York.
Drivers of Invasion and decreased invasive species cover with fully by homeowners; however, in this case, increasing soil moisture. abandoned and unmaintained properties We performed multiple regression to assess in residential areas also seem to serve as a reservoir for the invasive species found the most important drivers of invasion CONCLUSIONS within WFE. For the number of invasive in the WFE natural area. Additionally, species in each natural area plot, distance Urban and suburban areas are often consid- our results support other research on the from suburban edge and native richness ered the epicenters of plant invasions, yet importance of edge effects for facilitating were significant drivers R( 2 = 0.38, P > the processes that structure plant invasions plant invasions; here, distance from edge 0.0001) with plots closer to the forest edge in urban areas are not well understood was a significant driver of invasion at the (P < 0.0001) and plots with fewer natives (Gaertner et al. 2017). Here we found local scale. being more highly invaded (P = 0.10), that the most common nonnative invasive although not significant. Soil moisture, species in the residential communities were The reduction of the size of natural areas soil pH, light availability, and the percent also the most common in the natural area. and the subsequent increase in the pro- cover of native species were not signifi- This result supports a growing body of portion of edge habitats is a particularly cantly related to the number of invasive evidence that invasive species planted in widespread human-induced environmental species in the natural area plots. Distance residential areas are sources for invasions to change. Proximity to forest edge has been from the suburban edge (P = 0.003) and nearby natural areas (Sullivan et al. 2005; shown to be a predictor of invasion across soil moisture (P = 0.10) were found to be Alston and Richardson 2006; Hanspach many forest ecosystems (Brothers and Sp- important drivers of the percent cover of et al. 2008; Gavier-Pizarro et al. 2010; ingarn 1992; Honnay et al. 2002; Foxcroft invasive plant species in the natural area Bar-Massada et al. 2014; Cubino et al. et al. 2010). Forest edges are commonly (R2 = 0.18, P = 0.007). There was more 2015). This propagule pressure may stem drier (Chen et al. 1993), sunnier (Matlack invasive cover closer to the suburban edge from horticultural plantings done purpose- 1993), subject to higher temperature fluctu-
Volume 38 (4), 2018 Natural Areas Journal 263 ations (Kremsater and Bunnell 1999), and gardens, the more likely it is to be found the most important driver of nonnative experience higher levels of deer herbivory in surrounding natural areas (Marco et al. species composition. Social pressures and (Alverson et al. 1988) than interior habitats. 2010) and, in fact, the edges of natural aesthetics often drive management goals All of these characteristics can lower the areas often serve as a filter for nonnative and plant species composition in yards and habitat quality for native plant species, propagules, with nonnative species being gardens (Nassauer et al. 2009; Cook et making these edges more susceptible to unable to penetrate more than a few me- al. 2012) such that residents often mimic invasion by nonnative invasive species. ters past the highly invaded boundaries their neighbors in management decisions Nonnative invasive plants often have life of natural areas during the first stages of and species composition of their yards and history traits that allow them to colonize invasion spread (Foxcroft et al. 2010), a gardens (Minor et al. 2016). The small habitats that many native plants cannot result we found consistent with our study. variation in species composition among tolerate. The top three most frequently residential lots in this study points to ho- occurring nonnative species in edge plots The neighborhoods surrounding the WFE mogenization of species composition in in the WFE have all been shown to be contain many areas that are not subjected yards driven by human decision-making particularly tolerant to edge effects (Keane to regular maintenance. Some of these (Groffman et al. 2014). and Crawley 2002; Ashton and Lerdau properties were abandoned or repossessed 2008; Rawinski 2008). and some were areas between property lines that owners from neither side maintained. Management Implications In this system, high native richness may These areas had significantly higher nonna- Very few natural areas remain in the north- be an indicator of resistance to invasions. tive invasive species richness as compared eastern United States due to the high pop- Two mechanisms may be responsible for to properties that were occupied and un- ulation density of the area, and those that this observation. First, our results are derwent regular yard maintenance. These do remain are often surrounded by urban or consistent with other literature in the field properties may provide a reservoir for suburban developments. These areas are of showing that increased native biodiversity nonnative propagules that can potentially particular conservation value in the region. confers resistance to invasion. High native spread to natural areas like the WFE. In our Our work indicates that sources of both richness interferes with the establishment study, unmaintained areas were particularly planted and spontaneous nonnative invasive and success of nonnatives (Knops et al. dominated by L. japonica and R. multiflo- populations from surrounding urban and 1999; Kennedy et al. 2002; Hooper et ra, some of the most frequently occurring suburban development can contribute to al. 2005) by increasing competition and invasive plants within the WFE. This phe- the spread of invasives into natural areas. crowding and by decreasing available light nomenon has been documented in urban We propose two strategies that can address and soil nutrients (Naeem et al. 2000), Poland, where Fallopia spp. were found this. First, prevention in the form of public thus preventing nonnatives from becoming in increased abundance in unmaintained education on the impacts of horticultural overly dominant in communities with high areas (Soltysiak and Brej 2014). In towns invasions and second, management, in the native biodiversity. Second, in general, and cities, vacant lots are ubiquitous across form of invasive plant removal in private pineland forests, such as the one studied the landscape, and our work highlights the yards and gardens, vacant lots, and other here, are resistant to invasions (Howard et importance of managing these areas in unmaintained properties. al. 2004; Gurevitch et al. 2008) due to low addition to maintaining private yards and soil fertility and reduced light availability gardens to reduce the threat of invasions (Gurevitch et al. 2008). However, when to adjacent natural areas. Prevention and management of nonnative soil nutrients are increased, in particular invasive plant species lays not just in nitrogen and calcium, invasion resistance While nonnative invasive species composi- identifying probable invaders and rapidly is decreased in these pineland forests tion overlapped among residential lots and responding to these invasions, but also in (Gurevitch et al. 2008). Human activities natural area plots, beta diversity was much heightening public awareness. In general, in the suburban landscape, such as applying lower across residential lots. In particular, public awareness of invasive plant species lawn fertilizers, may result in increased soil we found less variation in species compo- begins only after a species has invaded an nutrients at the forest edge, reducing the sition among invasive plant communities in area. Educating the general public early, resistance conferred by low soil fertility. residential lots, including abandoned and before a known invasive species estab- unmaintained lots, than those nonnative lishes in a new area, will likely decrease At the neighborhood scale, nonnative inva- plant communities in the natural area. This the abundance of these species in gardens sive species richness did not significantly points to the difference in processes that and, therefore, decrease the likelihood that differ from richness within the WFE. There structure nonnative plant communities in a species will escape to adjacent natural is evidence that propagule pressure from residential areas vs. natural areas. As we areas. Public education is necessary to neighborhoods is a strong factor in the have shown here, distance to edge, native prevent invasions by reducing the pur- spread of nonnatives into natural areas species richness, and soil moisture were the chase of horticulturally popular species (Sullivan et al. 2005; Alston and Rich- most important determinants of invasive in neighborhood areas. After education ardson 2006). The higher the frequency at species composition in the natural area. regarding the threats of nonnative invasive which a species is planted in neighborhood In residential lots, human influences are plants, property owners are less likely to
264 Natural Areas Journal Volume 38 (4), 2018 purchase these plants for use in their yards field. Any use of trade names is for de- fragmentation and alien plant invasion of and gardens (Reichard and White 2001). scriptive purposes only and does not imply central Indiana old growth forests. Conser- Educational outreach can be coupled with endorsement by the US government. The vation Biology 6:91-100. regulation of nurseries to both reduce findings and conclusions in this article are Burt, J.W., A.A. Muir, J. Piovia-Scott, K.E. nonnative sales and increase the use of those of the authors and do not necessarily Veblen, A.L. Chang, J.D. Grossman, and native plants in landscape design. Increased represent the views of the US National H.W. Weiskel. 2007. Preventing horticultural introductions of invasive plants: Potential collaboration between nursery owners, Park Service. efficacy of voluntary initiatives. Biological homeowners, and ecologists will provide Invasions 9:909-923. a scientific basis for bans on the sale of [CEPF] Critical Ecosystem Partnership nonnative plants, particularly those shown Elena Tartaglia is a professor in the Fund. 2016. North American Coastal to demonstrate high invasiveness (Gagliardi Biology and Horticulture department at Plain. Accessed 26 September 2016 and Brand 2007; Marco et al. 2010). Bergen Community College. Her research from
Volume 38 (4), 2018 Natural Areas Journal 265 Gordon, D.R. 1998. Effects of invasive, richness on invasion dynamics, disease alien/bkgd.htm#problem>. non-indigenous plant species on ecosystem outbreaks, insect abundances and diversity. Noss, R.F., W.J. Platt, B.A. Sorrie, A.S. Weakley, processes: Lessons from Florida. Ecological Ecology Letters 2:286-293. D.B. Means, J. Costanza, and R.K. Peet. Applications 8:975-989. Kremsater, L., and F. Bunnell. 1999. Edge 2015. How global biodiversity hotspots Groffman, P.M., J. Cavender-Bares, and N.D. effects: Theory, evidence and implications may go unrecognized: Lessons from the Bettez. 2014. Ecological homogenization to management of western North American North American Coastal Plain. Diversity of urban USA. Frontiers in Ecology and forests. Pp. 117-153 in J.A. Rochelle, L.A. and Distribution 21:236-244. the Environment 12:74-81. Lehmann, and J. Wisniewski, eds., Forest Pimentel, D., R. Zuniga, and D. Morrison. 2005. Gurevitch, J., T.G. Howard, I.W. Ashton, E.A. Fragmentation: Wildlife and Management Update on the environmental and economic Leger, K.M. Howe, E. Woo, and M. Lerdau. Implications. Brill, Leiden, The Netherlands. costs associated with alien-invasive species 2008. Effects of experimental manipulation La Sorte, F.A., M.F.J. Aronson, N.S.G. Wil- in the United States. Ecological Economics of light and nutrients on establishment of liams, L. Celesti-Grapow, S. Cilliers, B.D. 52:273-288. seedlings of native and invasive woody spe- Clarkson, R.W. Dolan, A. Hipp, S. Klotz, I. Radeloff, V.C., R.B. Hammer, S.I. Stewart, J.S. cies in Long Island, NY forests. Biological Kühn, et al. 2014. Beta diversity of urban Fried, S.S. Holcomb, and A.J. McKeefry. Invasions 10:821-831. floras among European and non-European 2005. The wildland–urban interface in the Hanspach, J., I. Kühn, P. Pyšek, E. Boos, and cities. Global Ecology and Biogeography United States. Ecological Applications S. Klotz. 2008. Correlates of naturalization 23:769-779. 15:799-805. and occupancy of introduced ornamentals [LIISMA] Long Island Invasive Species Rawinski, T.J. 2008. Impacts of white-tailed in Germany. Perspectives in Plant Ecology, Management Area. 2016. Non-native Plant deer overabundance in forest ecosystems: Evolution and Systematics 10:241-250. Species Invasiveness Assessment. Cornell An overview. USDA Forest Service, New- Hejda, M., P. Pysek, and V. Jarosik. 2009. Impact University, Ithaca, NY. 266 Natural Areas Journal Volume 38 (4), 2018 Appendix. All species found in natural areas at the William Floyd Estate, Mastic Beach, New York. *Indicates plant species not native to the area. Acer palmatum* Oxalis stricta Acer platanoides* Parthenocissus quinquefolia Acer rubrum Phragmites australis* Alliaria petiolata* Pinus rigida Allium vineale* Poaceae Amelanchier canadensis Prunus serotina Aralia elata* Pteridium aquilinum Aralia nudicaulis Quercus alba Arisaema triphyllum Quercus rubra Aronia arbutifolia Rhododendron viscosum Artemisia vulgaris* Robinia pseudoacacia* Berberis thunbergii* Rosa multiflora* Carex spp. Rubus spp. Carya glabra Sassafras albidum Carya tomentosa Smilax glauca Celastrus orbiculatus* Smilax rotundifolia Chimaphila maculata Solidago spp. Clethra alnifolia Symplocarpus foetidus Cornus kousa* Taraxacum officinale* Cypripedium acaule Toxicodendron radicans Daucus carota* Vaccinium spp. Dennsteadtia punctiloba Verbena spp. Elaeagnus umbellata* Viburnum acerifolium Epipactis helleborine* Viburnum dentatum Forsythia spp.* Viola spp. Fragaria vesca Vitis spp. Gaultheria procumbens Wisteria spp.* Gaylussacia baccata Ilex spp. Impatiens capensis Lindera benzoin Lonicera japonica* Maianthemum canadense Maianthemum stellatum Medeola virginiana Melampyrum lineare Monotropa uniflora Nyssa sylvatica Osmundastrum cinnamomeum Volume 38 (4), 2018 Natural Areas Journal 267