INTRODUCTION
Plant diversity in protected areas is due to spatial heterogeneity among them. In particular, if the area includes various habitats, plant diversity is relatively high (Whittaker, 1972; Pickett and Thompson, 1978). Ecological niche differentiation is one of the key principle for the plant diversity (Hutchinson, 1957; Chesson, 2000; Holt, 2009; Pearman et al., 2008). However, because plants continuously compete with each other for limited resources such as light, nutriment, water and space, plant diversity in a region cannot be explained with only ecological niche differentiation. In adition to ecological niche differentiation, habitats diversity is a highly important concept in explaining regional plant diversity (Whittaker, 1972).
A wetland is a special ecosystem different from other habitats and it provides different ecological niche and space. Furthermore, it supports various plant species by providing different environmental gradients within its environment. Due to such characteristics, wetlands are highly important at the regional and national levels for the maintenance and preservation of various plant species (Whittaker, 1972; Ministry of Environment, 2012a). Most of peatlands in the world are distributed in high-latitude regions: Russia, Northern Europe, North America, etc. (Lappalainen, 1996; Montanarella et al., 2006). However, they are very rare in Korea due to its cool temperate climate and geological factors. In case of peatlands in Korea, there are Yongneup of Mt. Daeam, Mujechineup, Hwaeomneup, Mt. Sinbul Wetland, Sajapyeong Alpine Wetland and 1,100 Altitude Wetland, but Yongneup of Mt. Daeam is the only high moor among them (Ministry of Environment, 2012a). Yongneup of Mt. Daeam was designated as a natural reserve in July 1973 owing to its rarity and unique plant species, and in March 1998, it was registered on the Ramsar wetland list as the first Korean wetland (Ministry of Environment, 2007). In August 1999, Yongneup was designated as a wetland conservation area in accordance with the Wetlands Conservation Act. It was also designated as Korean Natural Monument No. 246 by the Cultural Heritage Administration, and as a protected area for forest genetic resources managed by the Korea Forest Service (Ministry of Environment, 2012a). Various studies were conducted on Yongneup due to its importance. Among them, Lee (1988) studied plants distributed in Yongneup and reported on 200 taxa; Lee et al. (2003) reported on 218 taxa in Keun-Yongneup and 139 taxa in Jageun-Yongneup based on a "research on the flora in the natural reserves of Mt. Daeam and Mt. Daewoo"; Kim et al. (2005) reported 63 taxa. The National Institute of Environmental Research of the Ministry of Environment, reported on 251 and 233 taxa in 2007 and 2012 respectively, according to an "intensive survey on the wetland protected areas" it carries out every five years. In 2009, the Wonju Regional Environmental Office of the Ministry of Environment reported on 341 taxa after conducting a survey. The difference in the survey results could be due to the different survey periods, time spent on survey, researchers and the area of study site. In particular, there is a big difference among the research papers on the number of taxa in Yongneup. To overcome this problem and provide accurate information on the flora, the most important information of an ecosystem, Choung et al. (2009) compared and discussed 18 controversial taxa. However, some taxa still remain controversial.
Because the ecological niche breadth of plants that inhabit wetlands is relatively very narrow, they are relatively easily influenced by the external environment (Choung et al., 2009). In particular, peatlands like Yongneup can be easily affected by changes in the environment due to eutrophication and inflow of soil, and artificial disturbance was observed in some areas in the past. However, at present Yongneup is relatively well preserved owing to the control of access to the area by a military base and the management agency Wonju Regional Environmental Administration of the Ministry of Environment, and vegetation restoration for the prevention of soil inflow.
A considerable time has passed since the flora of Yongneup was first reported by Lee (1969), and there is a possibility of a change in the flora due to environmental changes (Choung et al., 2009). However, it is difficult to simply compare the lists in the papers that have reported on the flora. Therefore, the purpose of this study is to secure basic data on vascular plants that inhabit the Yongneup wetland protected area. Also, this study aims to provide data for the preservation and management of Yongneup by surveying the current distribution status of endangered wild plants, specific plants and naturalized plants, as well as the basis for a soundness assessment, and an introduction to the information on the habitat of Pseudostellaria baekdusanensis M. Kim for the first time.
MATERIALS AND METHODS
1.Survey Site Information
The Yongneup wetland protected area in Mt. Daeam is located in Seoheung-ri, Seohwa-myeon, Inje-gun, Gangwon-do (Figure 1). Its total area is 1.36 km2 after a new wetland, which was found on the north side of the existing wetland protected area, was annexed to it and designated as a wetland protected area in 2010 (Ministry of Environment, 2012a). It is 1,050 m~1,280 m above sea level, and is composed of the peatlands in Keun-Yongneup (30,820 m2), Jaegeun-Yongneup (11,500 m2) and Aegi-Yongneup (12,000 m2) and the surrounding mountainous areas (Ministry of Environment, 2012a). It was reported that Yongneup of Mt. Daeam was first created about 4,000 years ago (Kang, 1976), and according to a recent study result, it is estimated to have first been created about 5,900 years ago (Kang et al., 2010).
The annual average temperature of Inje-gun, where the Yongneup wetland protected area is located, is 10.1 °C and its annual precipitation is 1,210.5 mm (Inje meteorological station, 2013; Table 1). The annual average temperature of Yongneup is 3.3 °C, its annual precipitation is 1,251 mm and the amount of snowfall reaches 3.7 m (Kang and Takahito, 2005). In case of the geological features of Yongneup wetland protected area in Mt. Daeam, it contains granitic gneiss, and these rocks are coarse grained and composed of quartz, microcline, perthite, biotite and garnet (Ministry of Environment, 2007; Zhu, 2011). Such rocks easily break into granules due to weathering (Zhu, 2011).
2.Study Methods
Vascular plants distributed in the Yongneup wetland protected area in Mt. Daeam were surveyed after subdividing the area into five large zones (Figure 1). The five zones are Keun-Yongneup (A), the mountainous areas that surround Keun-Yongneup (B), Jageun-Yongneup and the mountainous areas that surround Jageun-Yongneup (C), Aegi-Yongneup (D, designated as a wetland in 2010) and the mountainous areas that surround Aegi-Yongneup (E, included in 2010). The setting of survey scope and the divide of mountainous areas were based on the boundary of the edges of the open areas and forest vegetation in the wetlands. It was identified that Jageun- Yongneup lost most of its original form due to disturbances, and the wetland area and the forest area were not divided owing to the unclear boundaries. Table 2
A total of 15 surveys on the Yongneup wetland protected area were conducted from April 23 to November 11 in 2013. Plants that were observed in each zone were recorded and taken pictures of at the site, and collected as samples. Also, additional surveys were conducted four times from May to October in 2014. This study referred to the papers of Lee (1999; 2003), Lee (2006) and Lee (1996a; 1996b) for the identification of vascular plants, and the Korean Fern Society (2005) and the Korea National Arboretum (2008) for pteridophyte. Also, this study referred to Oh (2006), Yim (2000) and Hoshino and Masaki (2011) for the identification of Cyperaceae plants, and Korea National Arboretum (2004) for gramineous plants. Because there was a big difference among the researchers regarding the Korean endemic species (Park et al,. 2013), this study referred to data from the Ministry of Environment (2005). This study referred to Park (1995; 2001; 2009) and Alien Plants in Korea (http://ecosystem. ier.o.kr/alienspecies/) of the National Institute of Environmental Research (2013) for the identification of naturalized plants, and as for the identification of floristic special plants, it referred to the 4th National Natural Environment Research Guidelines (flora) established by the Ministry of Environment (2012b), and the Ministry of Environment (2012c) for endangered wild plants. As for the plants list, this study referred to the data in Lee (1996b)'s paper, which complemented the Eagler classification (Melchior, 1964), and the Flora of Korea Editorial Committee (2007) for botanical names, and put them in alphabetical order.
RESULTS AND DISCUSSION
1.Vascular Plants
A total of 376 taxa, which are composed of 73 families, 217 genera, 322 species, 3 subspecies, 44 varieties and 7 forms, were observed in the Yongneup wetland protected area (Table 2). Through this survey, a total of 298 taxa were collected as the voucher specimens (Appendix 1).
Through this study, 58 taxa, which were not recorded in the previous papers, were additionally surveyed. There is a significant difference between the results of this study and that of the intensive survey on the wetland protected areas (2007: 251 taxa, composed of 65 families, 171 genera, 207 species, 1 subspecies, 36 varieties and 7 forms; 2011: 233 taxa, composed of 67 families, 163 genera, 211 species, 4 subspecies, 24 varieties and 2 forms) which was carried out by the National Institute of Environmental Research of the Ministry of Environment. Such difference is due to the difference in the survey course and survey period, and the difference in the taxonomical opinions of observed species. As a result, along with Eriophorum gracile, which are very limitedly distributed, Carex erythrobasis, Carex drymophila, Carex heterolepis, Carex laevissima, Carex lasiocarpa var. occultans, Carex meyeriana, Carex planiculmis, Carex rostrata var. borealis, Carex sabynensis, Carex sabynensis var. rostrata, Carex xiphium, Eleocharis congesta, Eleocharis congesta var.
thermalis and Rhynchospora fujiiana were newly observed.
Among the plants that were observed in the five zones, in the wetland area of Keun-Yongneup, a total of 144 taxa, which are composed of 48 families, 105 genera, 119 species, 24 varieties and 1 form, were surveyed (Table 2). This result is similar to that of Choung et al. (2009), which reported a total of 130 taxa, composed of 46 families, 93 genera, 107 species, 1 subspecies, 19 varieties and 3 forms. Especially, we identified the distribution of 34 taxa which are distributed only in the wetland area (Table 3).
Although the Yongneup wetland protected area is relatively small, it was evaluated be rich in biodiversity. This means that there are various habitats in the Yongneup wetland protected area (Whittaker, 1972; Pausas and Austin, 2001). Diverse habitats support various plant species, and changes in their physical and biological environments are slower than that of vegetation areas, thus preventing plants species from extinction (Connell and Slatyer, 1977). Due to such characteristics, species that inhabit wetlands are very vulnerable to changes in the environment (Choung, 2009; Kim, 2004). Some places in the Yongneup wetland protected area also experienced sudden changes in the past, but places that did not experience any changes are well preserved, and it is judged that various plants are distributed owing to the efforts to prevent rapid environmental changes (Choung et al., 2009).
The protected areas including the Yongneup wetland protected area are isolated like islands (MacArthur and Wilson, 1963). In particular, for mountainous wetland protected areas located at high altitudes like the survey site of this study is the highly isolated area. Pickett and Thompson (1978) argued that appropriate size, level and cycle of internal dynamics are necessary for the maintenance of biodiversity (Pickett, 1980; Lerouxa et al., 2007; Grubb, 1977). It is judged that the current rare plants population such as Gentiana jamesii, Utricularia intermedia, Menyanthes trifoliata, Trientalis europaea var. arctica, Carex chordorrhiza and Lychnis wilfordii. which only inhabit the peatlands in Yongneup, are the result of going through a small-scale extinction and recolonization process due to the integration of the internal dynamics of the wetland and the ecological niche (Dupré and Ehrlén, 2002; Wilkinson, 1999). Therefore, in order to maintain and sustain plant diversity in the Yongneup wetland protected area, it is necessary to, first assess the ecological processes and factors that are associated with the sustainability of population; second, understand the ecological niche and life history of species that need to be preserved; and third, establish and promote an appropriate management plan so that the ecological processes associated with the sustainability of the target species can be maintained. In this sense, this study is meaningful as it provides the basic data necessary for the preservation activity.Figure .2
2.Endangered Wild Plants
The endangered wild plants that are distributed in the Yongneup wetland area (Ministry of Environment, 2012b) can be classified into five taxa: Trientalis europaea var. arctica, Lilium dauricum, Halenia corniculata, Lychnis wilfordii and Menyanthes trifoliata (Figure 3). Among them, Trientalis europaea var. arctica, Lychnis wilfordii and Menyanthes trifoliata were distributed in Keun- Yongneup, Jageun-Yongneup and Aegi-Yongneup, and Lilium dauricum and Halenia corniculata were found in the open areas adjacent to the woodlands (Table 4). In particular, all three endangered wild plants that were distributed in the wetlands were observed in Keun- Yongneup, which is relatively well preserved, and Aegi- Yongneup, which was newly discovered and included as a wetland protected area. Meanwhile, only Lychnis wilfordii was distributed in Jageun-Yongneup, which was stressed by artificial disturbance.
Over 10,000 individuals of Trientalis europaea var.
arctica were broadly distributed in Keup-Yongneup and Aegi-Yongneup, maintaining a stable population. At least 2,000 individuals of Lychnis wilfordii (Regel) Maxim. were broadly distributed in Keup-Yongneup, Jageun- Yongneup and Aegi-Yongneup, maintaining a stable population. Although Menyanthes trifoliata L. was narrowly distributed in Keup-Yongneup, Jageun-Yongneup and Aegi-Yongneup, at least 1,000 individuals were observed. However, continuous observation is required because only two individuals flowered. Halenia corniculata is a typical biennial plant, and changes in its population need to be continuously observed. In case of Lilium dauricum, 10 individuals were distributed near the military training ground.
3.Korean Endemic Plants and Naturalized Plants
A total of 24 taxa, which are composed of 16 families, 23 genera, 19 species, 3 varieties and 2 forms, of Korean endemic were observed in the Yongneup wetland protected area (Appendix 1). This corresponds to 6.4% of the plants that were observed through this study. There is a significant difference in the number of observed Korean endemic plants in the results reported by researchers and institutions: the Ministry of Environment and the Korea Forest Service reported 527 and 360 taxa respectively (Park et al., 2013). Therefore, depending on which data is used, there may be a great difference in the reported genus of Korean endemic plants that appear in a survey site. Due to such problems, Park et al. (2013) reported in their review on the Korean endemic plant list that there are only 59 Korean endemic species after excluding simple errors, taxa that need taxonomical review and taxa distributed in the neighboring countries. If we reexamine the Korean endemic species distributed in the Yongneup wetland protected area based on Park et al. (2013)'s paper, only eight species are valid: Cirsium setidens, Hanabusaya asiatica, Carex erythrobasis, Vaccinium hirtum var. koreanum, Anemone koraiensis, Clematis fusca var. coreana, Megaleranthis saniculifolia, and Salix koriyanagi.
It was surveyed that there were 5 families, 10 genera and 11 species of naturalized plants distributed in the Yongneup wetland protected area (Table 5). Among them, Rumex acetosella and Bidens frondosa were designated as invasive alien plants by the Ministry of Environment. Naturalized species were mainly observed in the whole area of Jageun-Yongneup which was relatively more affected by artificial disturbances, and the mountainous areas surrounding Keun-Yongneup, where the vegetation was disturbed and military roads constructed. On the other hand, two and one species were observed in relatively well-preserved Keun-Yongneup and Aegi-Yongneup respectively. Based on such results, it is judged that the key inflow route of naturalized plants is the movement of people and supplies through the military roads. Also, an increase in the appearance frequency and the genus of naturalized plants is expected due to a rise in the number of people who come for ecological visits.
4.Floristic Special Plants
9 taxa of V class, 17 taxa of IV class and 33 taxa of III class of floristic special plants were observed in the Yongneup wetland protected area (Table 6). The Yongneup wetland protect area is a considerably important area from the floristic aspect, since there were 9 species of floristic special plants which were narrowly distributed and have a small number of population, and another 17 species that were distributed in one sub region. In particular, based on the result that 33 species that correspond to II class, the taxa that are distributed at more than 1,000m above sea level, were extended over two sub regions, this study could establish that the survey site was located at 1,000 m above sea level.
5.New distribution area of Pseudostellaria baekdusanensis M. Kim
Jo et al. (2014) reported that they found a new species of Pseudostellaria in Mt. Baekdu. Pseudostellaria baekdusanensis M. Kim is similar to the taxon of P. japonica (Korshinsky) Pax, which is relatively common in forests near the valleys located in the central and the northern parts of Korea. The body of Pseudostellaria baekdusanensis M. Kim is small, 9 ~ 13 cm, and cleistogamous flowers are not developed at its body. On the other hand, the body of P. japonica (Korshinsky) Pax is 25 ~ 35 cm, and there are 1 ~ 2 hairs on its stems. Also, not only long are hairs concentrated on leaf blade margins and midveins on the backside, but its flowers are cuspidate and cleistogamous flowers are formed at the axil, thus displaying a clear difference with Pseudostellaria baekdusanensis M. Kim (Jo et al., 2014, NIBRVP0000497577). During the survey on the Yongneup wetland protected area, this study could identify the same taxa reported by Jo et al. (2014), and compared the results with their morphological characteristics (Figure 4).
Pseudostellaria baekdusanensis M. Kim was distributed in the Keun-Yongneup and Aegi-Yongneup in Yongneup wetland protected areas. Its habitats were the forests located at the edge of peat wetland and transition zones. In particular, in case of Keun-Yongneup, Pseudostellaria baekdusanensis M. Kim was broadly distributed in places where most of the original form of peat wetlands was changed after soil erosion. Pseudostellaria baekdusanensis M. Kim in the Yongneup wetland protected area flowers from the end of May to the beginning of June. In case of reproduction, both sexual reproduction and asexual reproduction were observed. Tuberous roots are formed along the stems that stretch to the sides under the surface of the soil, and each tuberous root is developed into an independent individual. Due to such characteristics, the population of Pseudostellaria baekdusanensis M. Kim is densely and narrowly distributed (30 ind./100 cm2).
Jo et al. (2014) suggested that the major characteristic of Pseudostellaria baekdusanensis M. Kim is the non-formation of cleistogamous flowers, but they were observed at the lower part of stems towards the end of flowering season. Therefore, reexamination is required on the differentiation regarding the non-formation of cleistogamous flowers.
