Ryu et al. Journal of Ecology and Environment (2018) 42:15 Journal of Ecology https://doi.org/10.1186/s41610-018-0072-5 and Environment RESEARCH Open Access Distribution and current vegetation of Cakile edentula, an invasive alien species in Korea Tae-Bok Ryu, Dong-Hui Choi, Deokki Kim, Jung-Hyo Lee, Do-Hun Lee and Nam-Young Kim* Abstract Background: Cakile edentula (Bigelow) Hook. is a successful invader that has been propagating globally. In Korea, Cakile edentula was found in 2008 for the first time, in the east coast of Korean peninsula. Based on site surveys conducted thereafter, Cakile edentula has propagated in the east coast from Goseong to Jeongdongjin, Gangneung and in the west coast of city of Hwaseong of Gyeonggi-do Province, and Taeangun County of Chungcheongnam-do Province. Results: Cakile edentula has infiltrated into four different vegetation communities (syntaxa) (Calystegio soldanellae- Salsoletum komarovii Ohba, Miyawakiet Tx.1967; Elymo-caricetum Kobomugi Miyawaki 1967; Carex pumila;andCalystegia soldanella) belonging to phytosociological classes of saltwort (barilla) and coastal glehnia. Cakile edentula competes with dominant species such as the saltwort (barilla) and beach morning glory, causing qualitative changes in species composition. It also affects local ecosystems through its competition with indigenous species, causing destruction of the traditional landscape. Conclusions: However, competition of Cakile edentula with indigenous species and the resulting replacement of such species are limitedly reported. Potential competitors with Cakile edentula have not been found yet. In Northeast Asia, qualitative changes realized in local ecosystems due to invasion of Cakile edentula are significantly noticeable. These necessitate proper controls for this invasive alien species to protect and preserve coastal dune areas. Keywords: Invasive alien plants, Alien species, Current vegetation, Preserve coastal dune areas Background Cakile edentula shows high seed production, short Cakile (CAKILE Miller, Gard. Dict. Abr., ed. 4. 1754.) is cycle of growth and development, and high rate of a genus of annual or perennial herbs belonging to the settlement (Maun et al. 1990). Coastal sand dune is a family Cruciferae of which seven species are currently habitat exposed to natural or artificial disturbances at- growing in the northern hemisphere (Rodman 1974; tributable to moving sands, sea waves, winds, human Rollins 1993). Among them, Cakile edentula (Cakile interference, and so on (Chapman 1976) where a range edentula (Bigelow) Hook.) is an important constituent of dominant and expanding vegetations of Cakile eden- species in coastal dune vegetation (Taira and Hiroko tula are frequently found. Currently, the vegetation of 2006). It is distributed over the coast of North America Cakile edentula has been propagated in Japan (Asai (Barbour and Rodman 1970; Maun et al. 1990). Depend- 1983; Fukuda et al. 2013), Australia (Rodman 1986; ing on environmental gradient, zonal distribution of Cousens et al. 2013), New Zealand (Cousens and Cakile edentula extends from the forefront of coastal Cousens 2011), and the West and Atlantic coasts of dunes to stabilized sand dunes. Alien plants invading North America (Barbour and Rodman 1970). Invasion of disturbed habitats are characterized by high productivity Cakile edentula has negative effects such as competition and propagation power (Baker 1965; Harper 1977). with Cakile maritima or destruction of traditional land- scape (Barbour and Rodman 1970; Rodman 1974). In * Correspondence: [email protected] some places, invasive alien plants could become sources Division of Ecological Conservation Bureau of Ecology Research, National Institute of Ecology, Seo-Cheon Gun, Chungcheongnam Province 325-813, of qualitative changes in indigenous local ecosystems South Korea (Kiyosue and Asai 2009; Cousens and Cousens 2011). © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Ryu et al. Journal of Ecology and Environment (2018) 42:15 Page 2 of 8 In Korea, the presence of Cakile edentula in the shore Province have growth of Cakile edentula (Fig. 1). Sub- of the east coast of Gangneung City was first reported in sequent site surveys were conducted during March– 2008 (Kil and Lee 2008). The environmental characteris- October 2016 following coastal lines of the Yellow and tics of the original habitat are the same as our Korean East Sea. For these surveys, sites of habitats where environment. Despite the ecological and scenic import- Cakile edentula growed individually or collectively were ance of costal sand dunes, no subsequent studies delving selected. To identify the distribution of Cakile edentula, into issues related to Cakile edentula have been re- the size of population in respective habitats, latitude ported. Available information on ecological problems of and longitude thereof, altitude above sea level, and azi- Korean coastal sand dunes related to or attributable to muth were investigated. Values of latitude and longi- the invasion of Cakile edentula is limited. tude were obtained from Global Positioning System The objective of this study was to determine geograph- (GPS) measurements. ical distribution and ecological vegetation of Cakile To examine vegetations, phytosociological methods edentula in Korea. Besides, vegetation of Cakile edentula with emphasis on species composition and types of habi- was compared to indigenous vegetation in Korea to tats (Westhoff and van der Maarel 1978) described by examine changes in species composition of coastal dunes the school of Zürich-Montpellier (Z.-M.) (Braun-Blan- due to the invasion of Cakile edentula and identify simi- quet 1965) were used in this study to examine each site larity in vegetation of Cakile edentula compared to those invaded by Cakile edentula. in the community of Cakile edentula that invaded Japa- A total of 19 vegetation survey sheets (phytosociological nese coastal vegetation in Northeast Asia. Results ob- relevé) were collected from 29 sites in the East Coast. The tained from this study will clarify ecological issues west coast of the Korean peninsula was excluded from the related to coastal dune vegetation. They might contrib- site survey because the distribution of Cakile edentula ute to the control and restoration of coastal dune vege- there was concluded to be in the introductory stage of in- tation in Northeast Asia. vasion. To extract units of vegetation (syntaxa), the inte- grated classification involving a combination of traditional Methods methods of classification of the Z.-M. school (Becking Geographically, Korea resides in the peninsula in 1957) with those of numerical statistical analysis was used Northeast Asia surrounded by the East Sea, Yellow Sea, as described previously (Kim and Lee 2006). and South Sea (Fig. 1). Annual average temperature and Relative net contribution degree (r-NCD) values of annual precipitation in Korea are 6.6–16.6 °C and extracted units of vegetation were then comparatively 825.6–2007.3 mm, respectively (KMA 2012, 2017). The analyzed using the 64 vegetation survey sheets (phytoso- peninsula belongs to the area of temperate climate ciological relevé) of coastal dunes in Korea that were monsoon characterized by hot and humid summers free from invasion of Cakile edentula (Han 2012). and cold dry winters dominated by continental climate The value of r-NCD obtained from integrated consid- of wide daily temperature range (KMA 2012;Kimand eration of quantitative (coverage) and qualitative Lee 2006). The east coast of Korean peninsula facing (frequency) contribution of the newly appeared species the East Sea is characterized by its straight line while to existing plant community is regarded as an accom- the coast lines of the South and Yellow Sea are charac- plishment of reliability evaluation (Kim and Manyko terized by complex shapes developed by the formation 1994). Cases of vegetation in Japanese coastal dunes in- of ria coasts. There are approximately more than 133 vaded by Cakile edentula were also examined (Taira and coastal dunes in Korea. They are observed more fre- Hiroko 2006). Previous studies containing information quently from the coasts of the Yellow and South Sea of habitats and units of vegetation according to the (Yoon et al. 2010). Some coastal dunes of over 2 km in International Code of Phytosociological Nomenclature respective length are protected as national parks. (Weber et al. 2000) were used. However, most coastal dunes are damaged by human interferences such as seaside resorts, wharfs, and Results and discussion amusement facilities. This study was designed to exam- Present distribution and characteristics of Cakile edentula ine coastal dunes in Korea where invasive alien Cakile Vegetation of Cakile edentula was found on the east edentula was found. coast of the Korean peninsula ranging from the Anmok Bibliographic investigation on existing literature and Beach, Gangneung City, to the Hyanghori Beach of studies was conducted