Floristic study of bryophytes in Hangyeong Gotjawal (Cheongsu-ri), Jejudo Island
Article information
Abstract
Recently, it has become known that Gotjawal terrain is an important area, therefore the study on this area has conducted in the geological, ecological, and cultural aspects. The studies on bryophytes of Gotjawal, however, have not been sufficiently performed. This study presents a survey on the bryophytes of the evergreen broad-leaved forest of Cheongsu-ri at Hangyeong Gotjawal in the southwestern part of Jejudo Island, Korea. A total of 72 taxa belonging to the Bryophyta (18 families 43 genera 55 species) and Marchantiophyta (11 families 13 genera 17 species) were determined and the liverwort index was 23.6%. Predominant life-form was weft. The rates of the bryophytes dominating in mesic to hygric sites were higher than the bryophytes mainly observed in xeric habitats. These values indicate that the forests are widespread and dense in this study area. Upon an investigation of the substrates, the bryophytes on rocks were most diverse. The results appear to stem from the fact that volcanic rock masses of various sizes lay scattered over the study area, offering numerous micro-habitats for bryophyte due to one of the characteristics of Gotjawal. We suggest that more detailed studies should be conducted at the regional scale to establish the bryophyte flora of Gotjawal and the evergreen broad-leaved forests on Jejudo Island.
Jejudo Island was formed by volcanic activities and has the unique topological and geological features. In this unique volcanic terrain, forests established on lava flow are scattered around the island, known as “Gotjawal,” which is a newly coined compound word and comes from dialects spoken on Jejudo Island (Jeju Special Self-Governing Province, 2009; Yoon, 2014). It is difficult to access Gotjawal and use it for agricultural purpose, as the trees and vines are dense, rocks of various sizes are scattered randomly, and the depth of soil is shallow in Gotjawal. Therefore, thus far it has only been used for grazing cattle, making charcoal or as a firewood source and is commonly recognized as useless land (Jeon et al., 2012; Jeong, 2012, 2015; Yoon, 2014). Recently, however, it has become known that Gotjawal is an area inhabited by various plants and animals where unique and various ecosystems are also sustained; the area serves as a natural waterway of the type necessary to create underground water, and it has high preservation values (Jeon et al., 2012; Kang et al., 2013; Yoon, 2014; Jeong, 2015). In addition, its cultural importance has also emerged. Therefore, the scientific studies of Gotjawal have been conducted to examine geological, ecological, and cultural aspects (Jeong et al., 2013; Jeon et al., 2015). However, a floristic study of bryophytes has not been conducted, except for that Dongbaek-dongsan at Seonheul Gotjawal in the northeastern part by Yim et al. (2013) and Subtropical Forest of Nabeup-ri at Aewol Gotjawal in the southwestern part by Yim and Hyun (2018).
The area and range of Gotjawal terrain have not been yet established (Jeon et al., 2015). According to Song (2000), Gotjawal can be divided into four major terrains, i.e., Gujwa-Seongsan, Jocheon-Hamdeok, Hangyeong-Andeok, and Aewol. Among them, Hangyeong-Andeok Gotjawal terrain is divided into Doneori Gotjawal lava flow and Byeongak Gotjawal lava flow. Doneori Gotjawal lava flow begun from the vicinity of Doneri Oreum (439 m above sea level) and branched off into Wollyeong-ri, Hallim-eup and Yeongnak-ri, Daejeong-eup. Its flow distance is 12.5 km, which is longest of the Gotjawal lava flows. Byeongak Gotjawal lava flow was erupted from Byeongak Oreum (418 m above sea level). The distance is 9 km and wide is 2–3 km (Song, 2003a, 2003b).
The evergreen broad-leaved forest of Cheongsu-ri, which is a branch of Doneori Gotjawal lava flow of Hangyeong-Andeok Gotjawal terrain located in the southwestern part of Jejudo Island, is also known as Sanyang Gotjawal. This area consists of dense evergreen broad-leaved forests where Quercus glauca Thunb., Castanopisis sieboldii (Makino) Hatus., Neolitsea sericea (Blume) Koidz., and Machilus japonica Siebold & Zucc. etc. are distributed on thwide rock fields. In addition, various ferns such as Asplenium ritoense Hayata and A. varians Wall. ex Hook. & Grev. etc. are inhabit and form a unique landscape. The rare plants, Maesa japonica (Thunb.) Moritzi & Zoll. and Neocheiropteris ensata (Thunb.) Ching etc. are also inhabit. M. japonica is an evergreen shrub recently reported as unrecorded plants (Moon et al., 2006), and are known to be distributed only in this area and its environs. In addition, N. ensata forms the largest population in Korea. From these reasons, this area is considered very important region from an academic point of view. The area is adjacent to the village, and has been damaged by the grazing cattle, making charcoal, or as a firewood source in the past. The vegetation is currently restored. Plants, animals, and stones etc., however, can be collected without permission due to its easy access. Moreover, since it is managed jointly by the village, there is a possibility of serious damage if conservation measures are not taken. Therefore, it is necessary to investigate natural resources to enhance the value of the area, come up with specific management measures for the preservation of species and natural habitat, and induce the development of the area as an ecotourism destination that also contributes to improving the income level of local residents.
The purpose of this study was to establish a bryophyte flora of the evergreen broad-leaved forest of Cheongsu-ri at Hangyeong Gotjawal. Furthermore, this study aims to contribute to studies of the bryophyte flora of Gotjawal and the evergreen broad-leaved forests on Jejudo Island on a regional scale and to provide basic data for selecting relevant indicator species.
Materials and Methods
Field surveys
Field surveys were carried out in the evergreen broad-leaved forest of Cheongsu-ri at Hangyeong Gotjawal with an area of approximately 501,223 m2 (Fig. 1), a total of 7 times from August 2011 to September 2018.
The map showing the location of Evergreen broad-leaved forest of Cheongsu-ri and distribution of Gotjawal terrain, Jejudo Island, Korea. Gotjawal terrain designated by the Jeju Special Self-Governing Province (1997) are represented by colored areas.
Identification, nomenclature, and arrangement of taxa
The samples collected in the investigated area were identified at species level with macroscopic morphology and microscopic features using relevant literatures (Iwatsuki and Mizutani, 1972; Inoue, 1974, 1976; Choe, 1980; Noguchi, 1987, 1988, 1989, 1991, 1994; Gao et al., 1999; Iwatsuki, 2001; Li et al., 2001; Wu et al., 2002; Cao et al., 2003). The voucher specimens were deposited in Warm Temperate and Subtropical Forest Research Center in Korea (WFRC). Only one collection number for each taxon were cited to avoid repetition in the floristic list. The nomenclature and arrangement of taxa are followed the system which is proposed by Goffinet et al. (2009) and Crandall-Stotler et al. (2009) for the mosses and liverworts respectively.
Life-forms and substrates
The life-forms of bryophytes in the study area have been estimated using Mägdefrau (1982), and also they are given in the floristic list for each taxon. The records of substrates for each taxon were included in this list.
Number of bryophyte taxa and liverwort index
We compared the number of taxa and liverwort index of the evergreen broad-leaved forest of Cheongsu-ri at Hangyeong Gotjawal with other localities based on revealed literatures [i.e., Taebaeksan Mt. (Papp, 2008), Deogyusan Mt. (Choi et al., 2010; Yoon et al., 2011), Dongbaek-dongsan (Yim et al., 2013), Gayasan Mt. (Sin, 2016a), Sobaeksan Mt. (Sin, 2016b), and Subtropical Forest of Nabeup-ri (Yim and Hyun, 2018)]. The liverwort index, which is based on the character that the liverworts and hornworts tend to prefer more humid conditions than mosses, was calculated as follow (Nakanishi, 2001):
Results and Discussion
The number of taxa and liverwort index
In this study, a total of 72 taxa belonging to the Bryophyta (18 families 43 genera 55 species) and Marchantiophyta (11 families 13 genera 17 species) were determined (Appendix 1).
The comparison result for the number of taxa presented that evergreen broad-leaved forest of Cheongsu-ri at Hangyeong Gotjawal contained rich diversity of bryophytes for the area (Table 1). This is one of the characteristics of Gotjawal area, which is highly biodiversity despite its narrow area and altitude above sea level range.
Comparison to the bryophyte species richness levels and liverwort indexes of evergreen broad-leaved forest of Cheongsu-ri at Hangyeong Gotjawal and other localities.
The liverwort index, which is based on the character that the liverworts and hornworts tend to prefer more humid conditions than mosses. Therefore, it is useful to compare air humidity between different sites (Nakanishi, 2001). The liverwort index of the evergreen broad-leaved forest of Cheongsu-ri was 23.6% and this value indicates that the air humidity of investigated area was relatively lower than Sobaeksan Mt. (41.9%), Deogyusan Mt. (40.8%), Gayasan Mt. (37.6%), Subtropical Forest of Nabeup-ri (30.2%), Taebaeksan Mt. (29.2%), and Dongbaek-dongsan (27.0%) (Table 1). The liverwort index of the study area is the lowest in the Gotjawal area. Seonheul Gotjawal is a wet forest where wetlands and caves have developed due to pahoehoe lava, and where Castanopsis sieboldii (Makino) Hatus. and Quercus acuta Thunb. are relatively abundant. The western Gotjawal is mostly distributed on aa lava that a dry environment is maintained due to its high permeability, and Quercus glauca Thunb. dominated and Arachniodes aristata (G. Forst.) Tindale inhabits widely. However, Subtropical Forest of Nabeup-ri is small in area but very well-conserved forest for a long time. Whereas the trees of Hangyeong Gotjawal were considered to have been frequently used by local residents in that they have small diameter at breast height and developed coppice shoots and branches. Therefore, we think that formation of patches that maintain bright and dry environment affects the composition and distribution of bryophytes. In the forest within study area, the mosses mainly occurred in sunny and dry habitats such as Racomitrium japonicum Dozy & Molk., Ptychomitrium sinense (Mitt.) A. Jaeger, and Hypnum plumaeforme Wilson were confirmed. Since a floristic study of bryophytes of Korea has not been sufficiently conducted, it is difficult to compare and analyze the liverwort index data. Therefore, we suggest that more detailed studies on the bryophyte flora of Korea should be conducted at the regional scale.
Remarkable species
We think that Plagiochila furcifolia Mitt. (Bi-ja-nal-gae-i-kki) inhabits in this area is worthy of special mention. This liverwort is distributed in Japan (Iwatsuki and Mizutani, 1972), China (So, 2001), India (Singh and Barbhuiya, 2012), and Vietnam (Shu et al., 2017). In Korea, this species was found from Bijarim Forest at Gujwa-Seongsan Gotjawal for the first time (Choi, 2013) and from Subtropical Forest of Nabeup-ri at Aewol Gotjawal for the secund time (Yim and Hyun, 2018). In case of Japan, this bryophyte species is categorized as ‘near threatened species’ in Hyogo Prefecture and as ‘vulnerable species’ in Osaka Prefecture (EnVision Conservation Office, 2018.). The species that its distributions of Korea are not known except Gotjawal area in Jejudo Island and the range of distribution is also narrow until now. However, it is hard to recognize this liverwort as species limitedly distributed in Jejudo Island and assess its rarity or conservation status. Because, in the case of Korea, the bryophyte flora is an unexplored field which has studied by a few researchers aiming mainly at Jejudo Island and not been investigated yet at a regional scale. Therefore, we suggest that a comprehensive research on the bryophyte flora of Korea should be conducted continuously.
Life-forms
We estimated the life-forms for each taxon in the study area and presented in the Table 2. Predominant life-form was weft (22 species, 30.6%), followed by mat (18 spcies, 25.0%), tall turf (15 species, 20.8%), short turf and fan (5 species, 6.9%, each of them), and tail and cushion (3 sepcies, 4.2%, each of them). We analyzed the results based on the relationship between the adaptive strategy and life-form of bryophytes according to Kürschner (2004), Uyar et al. (2007), and Glime (2017). As a result, the rates of mostly pleurocarpous bryophytes (the life-forms of mat, weft, fan, and tail) dominating in mesic to hygric sites were 66.7%, whereas mostly acrocarpous bryophytes (the life-forms of tall turf, short turf, cushion, and Annual) mainly observed in xeric habitats were 33.3% (Table 2, Appendix 1). These values indicate that the forests are widespread and dense in the study area. It is meaningful that the rates of bryophytes of mesic to hygric site type in this area are lower than in Dongbaek-dongsan (70.6%) and Subtropical Forest of Nabeup-ri (76.2%) and identical to the data of liverwort index (Yim et al., 2013; Yim and Hyun, 2018). These values supported that the subtropical forest of Nabeup-ri and Dongbaek-dongsan are relatively more humid than the study area.
The number of taxa and percentage composition according to the life-forms of bryophytes in the study area.
Distribution pattern
We estimated the substrates for each taxon to investigate the distribution pattern. The number of taxa according to the substrate are presented in the Table 3. Upon investigation into substrates, the bryophytes on the rocks were most diverse as 59 taxa followed by soil (19 taxa), decayed tree (10 taxa), and bark (22 taxa). The results seem to be caused by that the volcanic rock masses of various sizes lay scattered over the study area offering a lot of micro-habitats for bryophytes due to one of the characteristics of Gotjawal, where the rocks of various sizes are scattered randomly.
The number of taxa according to the substrate in the study area.
Acknowledgements
We wish to express our sincere thanks to two anonymous referees for their invaluable comments to improve the manuscript.
Notes
Conflict of Interest
The authors declare that there are no conflicts of interest.
