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 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. 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