SHORT COMMUNICATION The preliminary study on some natural plant communities of the sandbars along eastern coast of peninsular Thailand Kitichate Sridith1 and Chukiat Laongpol2 Abstract Sridith, K.1 and Laongpol, C.2 The preliminary study on some natural plant communities of the sandbars along the eastern coast of peninsular Thailand Songklanakarin J. Sci. Technol., 2003, 25(1) : 103-113 Surveys on the natural plant communities on the sandbars along the eastern coast of the peninsular Thailand in three provinces, Nakhon Si Thammarat, Songkhla and Narathiwat, have been carried out. Most of the natural vegetation on these sandbars had been become extinct, except for some remnants, left as separated spots. Four sites of those remnants were explored in this preliminary study. The plant species com- position investigation and the primary analysis on community type through the Braun-Blanquet method of the four remnants show some common characters. These characteristics suggest that, in the past, the same vegetation may have dominated the landscape along the sandbars lying parallel to the seashore of Peninsular Thailand. Key words : plant communities, sandbars, Peninsular Thailand 1Dr. rer. nat. (Botanik), Department of Biology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, 2B.Sc. (Forestry), Narathiwat Provincial Forest Office, 80 Suriyapradit Rd. Amphoe Muang, Narathiwat, 96000 Thailand. Corresponding e-mail : [email protected] Received, 7 August 2002 Accepted, 21 October 2002 Songklanakarin J. Sci. Technol. The preliminary study on some natural plant communities Vol. 25 No. 1 Jan.-Feb. 2003 104 Sridith, K. and Laongpol, C. ∫∑§—¥¬àÕ °‘µ‘‡™…∞å »√’¥‘…∞1 ·≈– ™Ÿ‡°’¬√µ‘ ≈–ÕÕߺ≈2 °“√»÷°…“‡∫◊ÈÕßµâπ¢Õß —ߧ¡æ◊™µ“¡∏√√¡™“µ‘∫“ß·Ààß∫π —π∑√“¬µ“¡™“¬Ωíòßµ–«—πÕÕ° ¢Õ߇¢µæ√√≥惰…™“µ‘¿“§„µâ¢Õߪ√–‡∑»‰∑¬ «. ߢ≈“π§√‘π∑√å «∑∑. 2546 25(1) : 103-113 °“√»÷°…“ —ߧ¡æ◊™∫“ß·Ààß∫π —π∑√“¬∑’Ë¢π“πµ“¡·π«™“¬Ωíòßµ–«—πÕÕ°„π§“∫ ¡ÿ∑√¢Õߪ√–‡∑»‰∑¬„π 3 ®—ßÀ«—¥ ‰¥â·°à π§√»√’∏√√¡√“™ ߢ≈“ ·≈– π√“∏‘«“ æ∫«à“ —ߧ¡æ◊™µ“¡∏√√¡™“µ‘ à«π¡“°∂Ÿ°∑”≈“¬ ‡À≈◊Õ ‡æ’¬ß∫“ß à«π‡ªìπ∫√‘‡«≥¢π“¥‡≈Á° „π°“√»÷°…“‡∫◊ÈÕßµâππ’ȉ¥â ”√«® —ߧ¡æ◊™µ“¡∏√√¡™“µ‘ à«π∑’ˇÀ≈◊ÕÕ¬Ÿà∫π·π« —π∑√“¬ ‡≈◊Õ° ’Ë∫√‘‡«≥∑’ËÕ¬Ÿà·¬°®“°°—π·≈–Õ¬ŸàÀà“ß°—π„π “¡®—ßÀ«—¥ º≈°“√«‘‡§√“–Àå„π‡√◊ËÕßÕߧåª√–°Õ∫æ√√≥æ◊™ ·≈–™π‘¥ —ߧ¡æ◊™∑’Ë«‘‡§√“–À嵓¡«‘∏’ Braun-Blanquet · ¥ß∂÷ß≈—°…≥–√à«¡°—π¢Õß —ߧ¡æ◊™„π ’Ë∫√‘‡«≥π’È æÕ®–Õπÿ¡“π‰¥â„π ™—Èπµâππ’È«à“ ≈—°…≥– —ߧ¡æ◊™µ“¡∏√√¡™“µ‘¥—ß°≈à“«‡§¬‡ªìπ≈—°…≥– —ߧ¡æ◊™‡¥àπ∑’˵àÕ‡π◊ËÕ߇ªìπº◊π„À≠à´÷Ë߇§¬æ∫Õ¬Ÿà ∫π —π∑√“¬∑’Ë¢π“πµ“¡·π«™“¬ΩíòߢÕ߇¢µæ√√≥惰…™“µ‘¿“§„µâ¢Õߪ√–‡∑»‰∑¬ 1¿“§«‘™“™’««‘∑¬“ §≥–«‘∑¬“»“ µ√å ¡À“«‘∑¬“≈—¬ ߢ≈“π§√‘π∑√å Õ”‡¿ÕÀ“¥„À≠à ®—ßÀ«—¥ ߢ≈“ 90112 2 ”π—°ß“πªÉ“‰¡â®—ßÀ«—¥ π√“∏‘«“ ‡≈¢∑’Ë 80 ∂ππ ÿ√‘¬ª√–¥‘…∞å Õ”‡¿Õ‡¡◊Õß ®—ßÀ«—¥π√“∏‘«“ 96000 On the East Coast of Peninsular Thailand, Physical characteristics where a shoreline of emergence stretches, lie Soil many sandbars. These sandbars are parallel to The soil type of the study areas is podzols the shore. Each one is an old beach deposit, lying (spodozol). (Classification of soils according to inland in the form of low ridges or terraces (1.5- Burmham in Whitmore (1985)). The soil pH at 2.5 m high). Sediments deposited along the shore- the study sites is 4.5 - 5.5. line have produced these sandbars and offshore Climate bars (Pongsaputra et al, 1991). Sedimentation from Peninsular Thailand has a tropical monsoon the rivers and ocean currents had taken place on climate characterized by a distinct dry season from the shallow sea floor along the shoreline of the February to May and a high rainfall, affected by East Coast in the past. In the Tertiary period, the the south westerly wind from June to September peninsula had inclined leading to the emergence and the north easterly wind, from October to of the East Coast whilst the opposite site of the January. (Pongsaputra et al, 1991). peninsula was submerged beneath the water. Vegetation on podzols (Vithayarat, 1995). According to Whitmore (1975, 1985), the These sandbars are unique habitats for vegetation occurring on the coastal sandbars is plant communities, as they are topographically heath forest. It is the natural vegetation of the different from the swamp that separate these podzols that occurs in places where parent mate- sandbars from the inland areas. rials consist predominantly of quartz, e.g., beach The sandbars are suitable for many human sand, sandstone or quartzite. The greatest extent activities such as building, agriculture and indus- of heath forest in South-East Asia is in Borneo try on account of their good drainage. As a result, where it occurs around much of the coastline on over 80% of the original vegetation has become raised terraces of poorly consolidated coarse, extinct. sandy, marine and riverine sedimentation left stranded by the fluctuating sea-level of the late Songklanakarin J. Sci. Technol. The preliminary study on some natural plant communities Vol. 25 No. 1 Jan.-Feb. 2003 105 Sridith, K. and Laongpol, C. Pleistocene (Whitmore, 1985). Similar but less at Ban Ta-ling-chun, Chana district (Sridith, 2002). extensive terraces that also bear or once bore The surveys have been continued further along heath forest occur along the south coasts of the coast of Narathiwat province and Cha-uad Thailand and Cambodia (Whitmore, 1975,1985). district of Nakhon Si Thammarat province. Congdon (1982) mentions the heath forest in Thailand occurring in the Tarutao National Park Methods in Satul, Peninsular Thailand. The heath forest found on Tarutao Island has, however, lower cano- I. Surveys pies and contains fewer species than typical heath The surveys of the original vegetation along forest as described by Whitmore (1975, 1985). the coastal sandbars of the East Coast of Penin- The aim of the project are to survey all sular Thailand have been carried out in three the remnants of the original vegetation on these provinces i.e. Songkhla, Narathiwat and Nakhon- sandbars and offshore bars along the East Coast Si Thammarat. The study sites are indicated on of Peninsular Thailand. The study was confined the map (Figure 1). to the composition of the plant species, their in- vestigation and analysis of the primary community II. Flora and vegetation investigations type in Nakhon Si Thammarat, Songkhla and The plant collections were made at inter- Narathiwat. The surveys were completed in vals over the selected study sites, in order to com- Songkhla province. The only original remnant of pile a plant species list of each site. Voucher speci- vegetation on the Songkhla sandbars were found mens are deposited at PSU Herbarium. Samples of Figure 1. Map of peninsular Thailand showing the four study sites. Songklanakarin J. Sci. Technol. The preliminary study on some natural plant communities Vol. 25 No. 1 Jan.-Feb. 2003 106 Sridith, K. and Laongpol, C. plant community type in each site were analyzed, pentandra, Viscum articulatum are abundant (see using the Braun-Blanquet Method (Kent & Coker, also Sridith, 2002). Such characteristics are in ac- 1994). cordance with those of the heath forest (Whitmore, 1975,1985;Congdon, 1982) Results The analysis of plant community types from each study site using the Braun-Blanquet Plant community types method exhibits some common types in the plant The various types of plant community in communities e.g. Melastoma malabathricum each location have been analyzed to date, accord- ommunity; Rhodomyrtus tomentosa community; ing to the Braun-Blanquet Method (Table 1). Memecylon lilacinum-Vatica harmandiana com- munity. The first two communities are shrub Plant species composition communities while the other is a tree community. A species list of plants found in the study This suggests that the vegetations on the sandbars sites has been compiled (Table 2). have some characters in common too. These char- acters make them unique among other kinds of Discussion vegetations nearby, such as peat-swamp forest, dry-evergreen forest, etc. Moreover, there are In general, the vegetations of the four study other communities of plants, though less common, sites have some characters in common. They are: that have been found in three out of four of the low uniform canopies of trees; no trace of layering sites e.g. Syzygium grande - Shorea roxburghii among trees; many tree species have small and communities. They are tree communities distrib- sclerophyllous leaves, for instance Syzygium uted as separated spots in the area where found. gratum, Pouteria obovata, Rapanea porteriana; Melaleuca quinquenervia communities were the ground in some areas has a bryophyte cover; found at Songkhla (Chana) and Nakhon Si Tham- wiry climbers such as Hoya diversifolia are fre- marat (Cha-uad). This Melaleuca plant indicates quent; many epiphytes and photophytes occur- that the areas are disturbed, since Melaleuca ring near the ground; myrmecophytes such as quinquenervia is a secondary species often oc- Dischidia rafflesiana are also often found. Fur- curring in disturbed areas (Whitmore, 1975, thermore, the parasitic plants e.g Dendropthoe 1985; Suzuki, 1999; Tomita et al, 2000). Dipter- Table 1. The plant community types in each site. Plant community types Son.1 Nak.2 Na.31 Na.2 Catunaregam tomentosa community X X Dipterocarpus chartaceus community X X Melaleuca quinquenervia community X X Melastoma malabathricum community X X X X Memecylon lilacinum-Vatica harmandiana community X X X X Rhodomyrtus tomentosa community X X X X Schizea dichotoma-Doritis pulcherima community X X Glehnio-Spinificetum litorei community X Syzygium grande-Shorea roxburghii community X X X 1 Son.= Songkhla (BanTa-ling-chan Village, Chana) ; 2 Nak.= Nakhon Si Thammarat (Cha-uad near Railway Station) ; 3 Na. = Narathiwat: Na.1= Ban Sai Khao; Na.2 = Ban Kok Payom Songklanakarin J. Sci. Technol. The preliminary study on some natural plant communities Vol.