A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science in Botany Prince of Songkla University 2009 Copyright of Prince of Songkla University Jarearnsak Sae Wai
(Assoc. Prof. Dr. Krerkchai Thongnoo)
Dean of Graduate School
Thesis Title Diversity of Vascular Plants on the Cliffs and Rocky Ridges of
Sankalakhiri Range in Betong District, Yala Province Author
Mr. Jarearnsak Sae Wai
Major Program Botany
(Assoc. Prof. Dr. Kitichate Sridith)
(Assoc. Prof. Dr. Obchant Thaithong)
Thesis Title Diversity of Vascular Plants on the Cliffs and Rocky Ridges of
Sankalakhiri Range in Betong District, Yala Province
Mr. Jarearnsak Sae Wai
Major Program Botany
Academic Year 2009
A study on the diversity of vascular plants on the cliffs and rocky
ridges of Sankalakhiri range in Betong district, Yala province, was conducted from
October 2005 to February 2007. A total of 223 vascular plant species were recorded.
Seven species are lycophytes, 41 species are pterophytes, three species are
gymnosperms, 113 species are dicots and 59 species are monocots. The family
Orchidaceae is the largest group of vascular plants in the study area with 40 species.
Two species are expected to be new to science, i.e. Hoya sp., and Dendrobium sp. and
16 species are new records for Thailand, i.e. Syngramma minima Holttum,
Anodendron axillare Merr., Willughbeia tenuiflora Dyer ex Hook.f., Hoya imperialis Lindl., Elaeocarpus pedunculatus Wall. ex Mast., Didymocarpus citrinus Ridl., D. cordatus A. DC. var. cordatus, Henckelia bombycina (Ridl.) A. Weber, Paraboea elegans (Ridl.) B.L. Burtt, Pachycentria glauca Triana subsp. maingayi (C.B. Clarke)
Clausing, P. hanseniana Clausing, Coelogyne prasina Ridl., C. testacea Lindl.,
Dendrobium metrium Kraenzl., Epigeneium geminatum (Blume) Summerh. and
Geostachys penangensis Ridl. In addition, four alien species were recorded in the
study area, i.e. Ageratum conyzoides L., Chromolaena odorata (L.) R.M. King & H.
Rob., Clidemia hirta D. Don and Lantanacamara L.
Descriptions of 129 vascular plant species and status of these taxa
(common, uncommon, rare) together with ecological data, localities and distribution
ranges of each species are presented as well as photographs. All voucher specimens
have been deposited at the Prince of Songkla University Herbarium (PSU), with the
duplicates sent to Chulalongkorn University Herbarium (BCU); Department of
Bangkok Herbarium (BK); The Forest Herbarium, Department of
National Park Wildlife and Plant Conservation (BKF); Khon Kaen University
Herbarium (KKU) and Queen Sirikit Botanic Garden Herbarium (QBG). The
vegetation types in the study area are described and illustrated. The variations in
floristic composition of the vegetation on these mountain ridges are also discussed.
I would like to express my deep gratitude to my principal advisor and
co-advisor, Assoc. Prof. Dr. Kitichate Sridith and Assoc. Prof. Dr. Obchant Thaithong
for their kind advices and discussions throughout this study.
My great thankfulness goes to the examining committee members,
Prof. Dr. Puangpen Sirirugsa and Prof. Dr. Pranom Chantaranothai for their valuable
I thank to Dr. Axel Dalberg Poulsen for his help and suggestions and
Prof. Dr. Anton Weber, Prof. Dr. Cornelis Christiaan Berg and Mr. Bhanumas
Chantarasuwan for identification and confirmation of some of my collections.
I also wish to thank all of my colleagues and friends in Prince of
Songkla University for their friendship and various kinds of help.
This work was supported by the TRF/BIOTEC Special Program for
Biodiversity Research and Training grant (BRT) T_149011 and the Graduate School,
Prince of Songkla University.
Finally, my deep gratitude goes to my parents, my brothers and my
sisters for their kind supports.
Jarearnsak Sae Wai
List of Tables
List of Figures
List of Plates
2. Materials and Methods
Floristic and vegetation analyses
Part I: Floristic study
Part II: Vegetation study
4. Discussion and Conclusion
Scientific Name Index
LIST OF TABLES
Table Page 1 Location, geology, rock/soil pH, elevation and size of the study
2 Number of families, genera and species in major groups of vascular
plants found in the study sites.
3 Predominant families in each major group found in the study sites
4 Number of families, genera and species in the study sites.
5 Number of species recorded in two different sub-vegetation types on
quartzitic phyllite ridges.
6 Comparison of some different characters and sizes between Hoya plicata King & Gamble and Hoya micrantha Hook.f.
7 Comparison of some distinguished characters and phenological
patterns between Fagraea wallichiana Benth. and Fagraeafragrans Roxb.
9 Distribution types of 129 vascular plant species found in the study
10 Fruit types and fruit/seed maturity periods of 38 flowering plant
LIST OF FIGURES
Figure Page 1 Topographic map of Betong showing the elevations and the location
of study sites.
2 Geological map of Betong showing the geological structure and the
location of study sites.
Forest cover map of Betong showing the forest area and the location
of study sites.
4 Mean monthly maximum-minimum temperatures in Betong district
(data collected from January-December 2006).
Monthly rainfall during the study period, from Betong station
(240202) (data from the Meteorology of Yala province, unpublished
data) and number of rain days in
collected from January-December 2006).
6 Distances between the study sites (km).
7 The pie chart of habit/life form of vascular plant species found in the
8 Ten distribution patterns of 53 Malesian plant species found in the
chart showing the distribution of rarity status.
10 Number of flowering species during each month of the year, the
month of flowering was pooled over 2 years (2006-2007).
11 Patterns of peak flowering (type I-VI) and examples of plant
12 Frequency distribution
patterns of peak flowering (type I-VI).
13 Vegetation on Gunung Silipid.
14 Vegetation on Khao Hin Ban Chantharat.
15 Vegetation on Khao Hin Ban Bo Num Ron.
16 Venn-Euler diagrams of the numbers of species found in the three
different substrates (A) and among three quartzitic phyllite ridges
LIST OF FIGURES (Continued)
Figure Page 17 Cluster analysis dendrogram based on similarity of plant species
composition and their abundance among study sites.
recorded from three different areas.
Present study (A);
Pha Taem National Park (B), (source: Boonjaras, 2002);
Phu Hin Rong Kla National Park (C), (source: Sridith, 1989).
LIST OF PLATES
Plate Page 1 A-G. Gunung Silipid and its vegetation
2 A-F. Khao Hin Ban Chantharat and its vegetation
3 A-F. Khao Hin Ban Bo Num Ron and its vegetation
4 A-C. Khao Hin Ban Piyamit 2 and its vegetation
D-F. Khao Hin Ban Ko Mo 4 and its vegetation
5 A-B. Huperzia phlegmaria (L.) Rothm.
C-D. Huperzia squarrosa (G. Forst.) Trevis.
6 A-B. Lycopodiela cernua (L.) Pic. Serm.
C-D. Selaginella intermedia(Blume) Spring
E-F. Selaginella siamensis Hieron.
7 A-B. Selaginella strigosa Bedd.
C-D. Selaginella wallichii (Hook. & Grev.) Spring
E-F. Syngramma minima Holttum
8 A-B. Taenitis blechnoides (Willd.) Sw.
C-D. Asplenium affine Sw.
E-F. Asplenium nidus L. var. nidus 307
9 A-B. Asplenium pellucidum Lam.
C-D. Davallia denticulata (Burm.f.) Mett. ex Kuhn
E-F. Davallia heterophylla Sm.
10 A-B. Davallia pectinata Sm.
C-D. Davallia repens (L.f.) Kuhn
E-F. Davallia solida (G. Forst.) Sw.
11 A-B. Davallia trichomanoides Blume var.lorrainii (Hance) Holttum
C-D. Lindsaea bouillodii Christ
E-F. Pteridium aquilinum(L.) Kuhn
12 A-B. Cibotium barometz J. Sm.
C-D. Dipteris conjugata Reinw.
E-F. Dicranopteris linearis (Burm.f.) Underw.
CHAPTER 1 INTRODUCTION Mountain ridges, cliffs and rocky outcrops are clearly distinct and
unique habitats, their vegetation communities differ markedly from those of
surrounding areas. Such habitats, under these edaphic and microclimatic conditions,
are characteristically terrestrial/habitat islands. Moreover, mountain ridges, cliffs and
rocky outcrops among tropical rain forests can be regarded as the xeric islands
(Parmentier, 2003) and are often considered as models for studying ecology as well as
biogeography (Porembski et al., 1996). The isolated rocky outcrops in tropical Africa
are well known as the “inselbergs” and the vegetation on the so called inselbergs have
been studied by many botanists and ecologists (Barthlott et al., 1996; Porembski et al.,
1997; Burke et al. 1998; Burke, 2002; Parmentier, 2003; Müller, 2007; Porembski,
2007), however, in tropical Asia this term and the vegetation has been scarcely known.
In any case, the vegetation on non-limestone mountain ridges and rocky outcrops in
Malesian region is usually recognised as the heath forest and also called kerangas
(Whitmore, 1975; 1990; Davies and Kamariah, 1999). In conservation terms, heath
forest systems should be given priority for habitat conservation due to its fragile
ecosystem (Whitmore, 1990). In addition, there are several rare and endemic species
apparently restricted to the heath forest ecosystems (van Steenis, 1971; Wong, 1998).
In Thailand, there are very few comprehensive studies on flora and
plant vegetation on rocky outcrops. Most botanical works on rocky mountains have
been concentrated on rare and threatened plants in limestone and sandstone habitats in
the northern and northeastern parts of Thailand, there were some studies in Doi
Chiangdao (Santisuk, 1998; Nanakorn, 2003; Chayamarit et al., 2005), in Phu Kra
Dung National Park (Koyama and Phengklai, 1989), in Phu Hin Rong Kla National
Park (Sridith, 1989), in Pa Hin Ngam Forest Park (Suddee, 1995) and in Pha Taem
National Park (Boonjaras, 2002). In contrast to the situation in Peninsular Thailand,
there is very limited information about limestone as well as non-limestone flora.
The Penisular Thailand lies on the northern part of Thai-Malay
Peninsula, is one of the richest areas in diversity of habitat types and flora, it includes
the transition zone between Indo-Chinese and Malesian floristic regions (Takhtajan,
1986). According to van Steenis (1950), 575 genera of flowering plants have their
northern or southern range limits near Thai-Malaysian border, the boundary between
this two floristic regions is, here, taken as Kangar-Pattani line (Whitmore, 1975), and
this overlap should, then, be documented, thus adding value to the biodiversity of
Peninsular Thailand. Topographically, there are three main mountain ranges running
through the length of the peninsula, i.e. the Phuket, the Nakhon Si Thammarat and the
Sankalakhiri (Pongsabutra, 1991). Moreover, there are many scattered limestone
outcrops throughout the peninsula, while the high mountain ridges of these nearly
continuous mountain ranges are mainly composed of granite. These areas serve as
habitats for many rare and endemic plants. Therefore, they are very important for plant
genetic resource conservation. Nowadays, scientific knowledge of biodiversity on
rocky mountains in Peninsular Thailand is still limited, while many human activities
causes a significant increase in extinction risk of native plant species. The study in
order to get the account of the biodiversity, natural plant vegetation, rarity and
endemism on isolated habitats is urgently needed at the moment, especially in
Sankalakhiri range which is the natural border between Thailand and Malaysia, where
was less explored in the past.
Betong is the southernmost district of Thailand, which located in
Sankalakhiri range. It borders the Malaysian states of Kedah and Perak.
Phytogeographically, it falls in the peninsular floristic region (Smitinand and Larsen,
1970), which connected to Perak sub-province of Peninsular Malaysia. The Perak sub-
province is a special area of high diversity and endemism of plants, as it is the meeting
point of different floristic elements, including the Burmese-Thai elements, the
Sumatran elements and the Malayan elements (including endemic elements) (Ashton,
1992; Wong, 1998) and due to the fact that Betong district is next to the state of Perak,
Malaysia, therefore the flora of this sub-province which belongs to the Malesian
floristic region might continue to some parts of Peninsular Thailand, especially in
Betong, the southern most frontier of Thailand. However, it is such a pity that there
has been limited information concerning the flora and vegetation in this area. This
might due to the fact that the area of Betong and the adjacent areas are still
unexplored. Previously, botanical surveys in this area were mainly made by Dr. A.F.G.
Kerr in 1923 and 1925 (Jacobs, 1962). In the last decade, very few additional surveys
were made by the staff of the Forest Herbarium, National Park, Wildlife and Plant
Conservation Department, Ministry of Natural Resources, Bangkok. Some of these
collections were reported to be newly recorded species for Thailand (Lindsay et al.,
2003; Saensouk et al., 2003). It is, therefore, of interest in terms of diversity,
biogeography and conservation to study the vascular flora in this area.
Betong’s terrain is mostly mountainous and hilly area. Types of forest
are mostly tropical lowland evergreen forest (hill dipterocarp forest) and lower
montane forest according to Whitmore (1975). However, there are a few attractive
isolated mountain ridges, the edaphic climax formations, which include both limestone
and non-limestone areas, the non-limestone flora in the Peninsular Thailand was
poorly known compared with the limestone flora. Furthermore, some of these montain
ridges are being destroyed. The habitat destruction, invasion by alien species and over
exploitation are the main causes of biodiversity loss. Consequently, it is interested in a
study of plant diversity on non-limestone mountain ridges, which has never been
reported in Peninsular Thailand.
OBJECTIVES 1. To investigate diversity of vascular plants on the cliffs and rocky ridges of
Sankalakhiri range in Betong district, Yala province.
2. To obtain the details of morphology, ecology and geographical distribution of these
3. To study vegetation and compare the species composition of vascular plants
between the study sites (floristic similarity).
4. To increase the number of reference plant collections in Thai Herbaria.
LITERATURE REVIEW Botanical studies on rocky outcrops in tropical region Most botanical
works on rocky outcrops have been concentrated in
and floristically best known is the vegetation of west African
inselbergs. The information about flora, vegetation and their important in the
following works were mainly investigated from the the rocky outcrops in tropical
Africa and some studies in Australia:
Porembski et al. (1997) provided a general overview of plant
communities on tropical inselbergs and stated that flora and vegetation of inselbergs in
different geographical regions are clearly distinct. The most species-rich families of
African inselbergs are Fabaceae, Scrophulariaceae and Lentibulariaceae, while the
most species-rich families in South American inselbergs are Melastomataceae,
Orchidaceae, Cactaceae and Bromeliaceae. The vegetation of Indian inselbergs is
similar to the vegetation of African inselberg at the family and genus level.
Hunter and Clarke (1998) studied the flora and vegetation on granitic
outcrops in eastern Australia, 28 plant communities and 671 vascular plant taxa were
recorded. A high number of rare and threatened taxa have been found in these
communities and many of which are restricted to the rocky outcrops.
studied the plant communities on granite inselbergs and
six dolerite dykes in the central Namib desert, the nine plant communities were
recognised, these mentioned plant communities are reflected the diversity of habitats
and the high conservation value of inselbergs among the desert landscape.
Parmentier (2003) investigated species composition of three inselbergs
from continental Equatorial Guinea. The vegetation is dominated by monocotyledons
(Orchidaceae, Cyperaceae and Poaceae). Interestingly, although the inselbergs are
very close to each other, but they significantly differ in their vegetation and these
could be explained by the insular property of inselberg vegetation surrounded by rain
Müller (2007) studied on herbaceous vegetation of seasonally wet
habitats on inselbergs and lateritic crusts in west and central Africa, plant communities
were grouped into three large blocks, i.e. the communities of rock pools and shallow
depressions, mat vegetation and open pioneer communities. The spatial mosaics and
the vegetation dynamics were also discussed.
In contrast, information about flora and vegetation of rocky outcrops or
inselbergs in tropical Asian is very sparse. Botanical studies on limestone hills,
mountain ridges and summits in the Peninsular Malaysia are as follows:
Chin (1977) documented 1,216 species of vascular plants from
limestone hills in Peninsular Malaysia, there are 335 species characteristic of the
limestone flora and about 254 species are confined to limestone habitats. The
limestone vegetation was described and devided into nine subdivisions, i.e. base of
hills, talus slopes, hill slopes to about 60˚steepness, gullies and valleys, cliffs and near-
vertical slopes, summits with considerable soil cover, summits with none or very little
soil cover, coastal limestone and disturbed areas.
Stone (1981) reported the vegetation and flora of the summit region of
Gunung Ulu Kali (Genting Highland), two vegetation types (i.e. upper montane forest
and elfin-forest) and more than 460 species were recognised.
The other mountain summits in the Peninsular Malaysia such as
Cameron Highland, Fraser’s Hill, Gunung Jerai, Taiping Hill, etc., these mountain
peaks, sandstone plateau and quartzite areas are in effect island habitats and serve as
habitats for many rare and endemic plant species (Wong, 1998).
The botanical studies on rocky mountains in the northern and north
eastern of Thailand are as follows:
During August to September 1988, the Thai-Japanese botanical
expedition was undertaken by the cooperation between Thai and Japanese botanists.
The botanical expedition was made in Phu Kradueng National Park. About 13,000
sheets and 130 living plants were mainly collected from the summit plateau of Phu
Kradueng National Park (sandstone) (Koyama and Phengklai, 1989).
Sridith (1989) studied the flowering plants on rock platform of Phu Hin
Rong Kla National Park (sandstone). Eighty eight species were recorded, including 54
species of dicotyledons and 34 species of monocotyledons. The most species-rich
family was Orchidaceae.
Suddee (1995) studied the flowering plants in the Pa Hin Ngam Forest
Park (sandstone). One hundred and forty one species of dicotyledons were recorded.
The richest family
in number of genera and species was Fabaceae.
Santisuk (1998) investigated the vegetation and flora of Doi Chiangdao
(limestone). The enumeration of the threatened plants of Doi Chiangdao and the
information on their fragile habitat were provided. Eigthty nine species of rare and
endemic seed plant species in the montane zone were reported.
Boonjaras (2002) studied the flowering plants in Pha Taem National
Park (sandstone). One hundred and seven species were recognised, including 74
species of dicotyledons and 33 species of monocotyledons. The top three species rich-
families were Orchidaceae, Fabaceae and Scrophulariaceae. There were six endemic
species recorded in the area.
(2003) surveyed and collected the rare plants from Doi
Chiang Dao, three hundred herbarium specimens were deposited at the Queen Sirikit
Botanic Garden Herbarium (QBG) and additional living plant collections of some rare
and endangered species were collected and planted in the nursery of Queen Sirikit
Recently, Chayamarit et al. (2005) published the Flora of Doi
Chaiangdao. The information about flora and vegetation of Doi Chaiangdao were
presented. The species lists of plants were provided, including 93 species of rare and
Floristic inventories and botanical studies in Peninsular Thailand In 1930, F.W. Foxworthy an American
botanist worked in Peninsular
Malaysia surveyed and collected the plant specimens from the southern part of
Peninsular Thailand. Mainly based on the dominant species of Dipterocarpaceae,
Foxworthy (1979) stated that the plant species composition in the forests of two
southernmost provinces of Thailand (Yala and Narathiwat) is similar to that of the
Congdon (1982) studied the vegetation of Tarutao National Park, Satun
province. Ten vegetation types including the limestone vegetation and scrub forest on
the top of mountains were enumerated together with a vegetation map of the islands. A
total of 869 species were recognised, among these 105 species were found on
Maxwell (1986) documented 596 species and 128 families of vascular
plants from Ko Hong Hill in Hat Yai
district, Songkhla province. Many plant
specimens were partly collected from sandstone habitats and deposited at Prince of
Songkla University Herbarium (PSU).
Ramsri (1986) studied vascular plants at Gahrome Falls, Khao Luang
Natinal Park. Eighty one families, 174 genera and 220 species were recorded.
In 1990, The Thai-Danish botanical expedition was partly undertaken
from limestone habitats in Surat Thani, Trang, Songkhla and Yala provinces. This
botanical expedition was reported by Larsen (1992).
Sirirugsa et al. (1999) studied the diversity of vascular plants at Ton
Nga Chang Wildlife Sanctury. A total of 905 species, 444 genera and 129 families
and the vegetation types were classified into seven types based on
Niyomdham et al. (2000) reported three plant community types at
Hala-Bala wildlife Sanctuary in Yala and Narathiwat provinces, i.e. tropical lowland
rainforest, lower montane rainforest and vegetation over limestone hill. The stunt
shrubs and trees found on limestone hills belong mainly to the families Ericaceae and
Podocarpaceae (Ericaceae and Dacrydium community). There are several species of
orchids and ferns, and in addition Nepenthes spp. are commonly found.
Sridith (2002) studied the remnant of vegetation on a coastal sandbar in
Songkhla Province. Ninety eight plant species were recorded. Vegetation profiles of
study plots at Ban Ta-ling Chan village, Chana district were provided.
Laongpol (2003) studied the flora and vegetation along the coast in
Narathiwat province. One hundred and fifty seven species of vascular plants were
recorded. Ten plant communities were recognised, these plant communities were
grouped into three types of vegetation, i.e. dune grassland vegetation, dune scrub
vegetation and dune woodland vegetation.
Leeratiwong and Jornead (2003) studied the diversity of vascular plants
in Sriphangnga National Park, Phangnga. Five hundred and forty three species were
and the distribution of each species also was provided.
Previous accounts of botanical studies in Betong Dr. A.F.G. Kerr is one of the few botanists who surveyed and collected
the plant collections from Betong in 1923 and 1925. Sixty nine specimens were
collected, as recorded in detail by Jacob (1962).
Maknoi (2000) studied Zingiberaceae in Thai-Malaysian border.
Nineteen species of Zingiberaceae were collected from Betong. Of these, six species
were reported to be new records for Thailand.
In the last decade, many plant specimens collected from Betong have
been reported to be newly recorded for Thailand, e.g. Polyalthia lateritia J. Sinclair
(Bunchalee and Chantaranothai, 2002), Matonia pectinata R. Br. (Lindsay et al.,
2003), etc. Many Malesian elements in Thailand have only been found in Betong
district and they are also very rare species for Thailand, e.g. Argostemma subcrassum King (Sridith, 1999), Alpinia scabra (Blume) Baker (Saensouk et al., 2003), etc.
According to Pooma et al. (2005) in an account of threatened plants in
Thailand, many Malesian plants have only been found at Betong such as Pomatocalpa kunstleri (Hook.f.) J.J. Sm., Shorea macroptera Dyer, Ridleyandra kerrii A. Weber,
Dissochaeta conica (Bakh.f.) Clausing, Wightia borneensis Hook.f., Rhododendron jasminiflorum Hook.f., Disepalum pulchrum (King) J. Sinclair, Pinanga perakensis Becc., Breynia coronata Hook.f., Licuala scortechinii Becc., Alchornea villosa Müll.
Arg., Medinilla clarkei King and Medinilla scortechinii King.
From the literature review, it was found that the information of flora
and vegetation on mountain ridges and rocky outcrops in
the Peninsular Thailand is
very scarce, especially in Betong. Therefore, it was expected that many rare, poorly
known or undescribed species was to be found in this area.
CHAPTER 2 MATERIALS AND METHODS
STUDY AREA 1. Location Betong district is situated in the southernmost province of Thailand,
which located in Sankalakhiri range. It borders the Malaysian state of Kedah and
Perak. The northern part is next to Than To district of Yala province and Chanae
district of Narathiwat province is on its east border. The area lies approximately
between latitudes 5˚ 36'-6˚ 00' N and longitudes 100˚ 59'-101˚ 30' E, which covers an
area of 1,328 km
(Figs. 1-3), it is 140 km from Yala and 1,224 km from Bangkok.
2. Topography and geology The topography of Betong is mostly mountainous and hilly area, varied
in altitudes ranging from 140-1,535 meters above sea level (Fig. 1), the highest peak
of Sankalakhiri range on Thai-Malaysian border is Gunung Ulu Titi Basah. There are a
few small isolated rocky mountains scattered in the area, the approximate ranges of the
areas of these rocky mountains are about 5 to 10 hectares. Their topographic features
are characterised by the steep slopes, dome-shaped structure with the high cliffs. They
rise abruptly from the surrounding area. The geology of the area mainly consists of
two major types, i.e. Triassic granites and Devonian-Silurian metamorphic rocks
(Betong and Yaha formations). There are very few middle Permian limestone outcrops
(Ratburi group) near the town of Betong at Ban Ko Mo 4 (Fig. 2).
3. Climate ccording to
ppen’s classification system of climatic region analysis
in Kottek et al. (2006), the climate of Betong belongs to the tropical rain forest (AF)
climate. The precipitation in this area is under the influence of the southwest and
northwest monsoons. The average annual rainfall is usually above 2,000 mm per year
and there is no distinct dry season. Climatological data about study sites are available
from Betong district and the Meteorology of Yala province (Figs. 4-5). During the
study period (January-December 2006), a total of 160 rain days were recorded and the
heavy rainfalls occurred in the months of September and October. The relative
humidity of Betong region is high throughout the year. The summits of study sites are
usually fog-covered in the early morning throughout the year. However, the relative
humidity may drop below 60 % on the exposed ridges and when winds
average maximum and minimum daily temperatures in the foothills range from 20 °C
to 33 °C, but on the exposed areas of rocky ridges are drier and hotter than those shady
conditions in surrounding area. The day temperatures can reach higher than 40 °C in
sunny days, whereas at night and early morning, the temperatures may drop to 15 °C.
The lowest temperatures are usually recoreded in January and February, while the
highest temperatures occur between March and April.
4. Forest Forest area of Betong is about 50 % of the total area, approximately
including two protected areas in the eastern part, i.e. Bang Lang National
Park and Hala-Bala Wildlife Sanctuary. The other forest areas usually occur in high
altitudes near Thai-Malaysian border and some scattered in isolated patches on steep
slopes, mountain ridges and rocky outcrops (Fig. 3). According to Whitmore (1975),
types of forest in Betong region are mostly tropical lowland evergreen forest (hill
dipterocarp forest) and lower montane forest. The hill dipterocarp forest is dominated
by Shoreacurtisii Dyer ex King and the shaded palms, such as Eugeissonatriste Griff., Iguanura spp. and Pinangna spp., which are typically found in Malayan type
forest. The species composition of lower montane forest varies locally, it is usually
dominated by Dacrydium elatum (Roxb.) Wall. ex Hook. (Podocarpaceae);
Lithocarpus spp., Quercus spp. (Fagaceae); Schima wallichii (DC.) Korth. (Theaceae);
Rhododendron spp. and Vaccinium spp. (Ericaceae) (Niyomdham et al., 2000).
Figure 1. Topographic map of Betong showing the elevations and the location of study sites.
Figure 2. Geological map of Betong showing the geological structure and the location of study sites.
Figure 3. Forest cover map of Betong showing the forest area and the location of study sites.
Mean maximum temperatures
Mean minimum temperatures
Number of rain days
Figure 4. Mean monthly maximum-minimum temperatures in Betong district (data
collected from January-December 2006).
Figure 5. Monthly rainfall during the study period, from Betong station (240202)
(data from the Meteorology of Yala province, unpublished data) and number of rain
(data collected from January-December 2006). Numb er o f ra in da y s M o nthly ra infa ll ( mm ) T empera ture ( 0 C) Month Month
5. Study sites Five isolated study sites were chosen including non-limestone and
limestone areas in order to study diversity, plant species composition and floristic
similarity (Table 1, Figs. 1-3).
Table 1. Location, geology, rock/soil pH, elevation and size of the study sites.
Study site Geology Rock/Soil pH Elevation (m) Approximate area (hectare) A. Gunung Silipid
5° 53' N, 101° 09' E
B. Khao Hin Ban Chantharat
5° 47' N, 101° 12' E
C. Khao Hin Ban Bo Num Ron
5° 52' N, 101° 05' E
D. Khao Hin Ban Piyamit 2
5° 53' N, 101° 01' E
E. Khao Hin Ban Ko Mo 4
5° 48' N, 101° 03' E
The five study sites are isolated from each other by a matrix of different
habitats (lowland evegreen forest and/or rubber plantation), the study sites are 7 to
22.5 kilometers apart from each other (Fig. 6).
Figure 6. Distances between the study sites (km).
DATA COLLECTION 1. Exploration and plant collection
Surveying and collecting were conducted in the study sites at monthly
or bimonthly intervals from October 2005 to February 2007. Most plant taxa were
collected and made in the form of herbarium specimens (including both dry and spirit
specimens), but some species (lacking key characters, e.g. flower, fruit, fertile
segment, etc.) were only observed and noted. Ecological data, habitats, habit and
some diagnostic characters of each specimen, such as color, smell, etc. were noted
and photographs were taken in the field. Specimen processing followed the directions
specified in “ he Her arium Hand oo ” Foreman and Bridson,
2. Vegetation data collection
The photographs of all study sites (A-E) were taken showing the
structure of vegetation. The abundance of each species was registered in each study
site in order to investigate floristic similarity among study sites.
The abundance of each species was estimated by eye in terms of
percent cover as described by Kent and Coker (1992). The numerical scores based on
the subjective scales were recorded as follows:
LABORATORY STUDY The collected specimens were identified by using both keys and
descriptions from available taxonomic literatures (see citations) and compared with
identified herbarium specimens from Prince of Songkla University Herbarium (PSU).
The specimens were studied in detail of morphology under a
stereomicroscope such as indumentum, flower and fruit characters. Some small
morphological characters such as size and shape of seeds/spores, etc. were observed
and measured under a light microscope.
A description of each species was prepared based on specimens
collected at non-limestone study sites (A-D). In addition, ecological data and
geographical distribution of each species were retrieved from the literature.
For the plant name authors, other citations and abbreviation used in
this thesis are followed Brummitt and Powell (1992) and according to the
International Plant Names Index (IPNI) (The Plant Names Project, 1999). The
terminology concerning the morphology of plants are followed Harris and Harris
All voucher specimens have been deposited at the Prince of Songkla
University Herbarium (PSU), with at least three duplicates if possible sent to the other
Thai Herbaria, i.e. Chulalongkorn University Herbarium (BCU); Department of
Agriculture, Bangkok Herbarium (BK); The Forest Herbarium, Department of
National Park Wildlife and Plant Conservation (BKF); Khon Kaen University
Herbarium (KKU); Queen Sirikit Botanic Garden Herbarium (QBG) (abbreviation
according to Index Herbariorum).
Note: Because the main aim was to study the poorly known non-limestone species,
plants from the limestone site E were not described in detail. This site was only
included in the vegetation study.
FLORISTIC AND VEGETATION ANALYSES Floristic richness of each non-limestone study site (A-D) was
determined by directly counting the number of species, genera and families
documented. The estimated species richness of each non-limestone study site as well
as all non-limestone study sites were calculated using species-area curves.
Habit/lifeform and habitat classification methods were used to classify
the vegetation on quartzitic phyllite ridges into subdivisions. The vegetation
descriptions of all study sites (A-E) and the illustrations of some selected study sites
(A-C) were prepared together with photographs.
Floristic similarity among study sites (A-E) was analysed according to
plant species composition and their abundance. Cluster analysis was performed with
PC-ORD software version 3.2 using the Sørensen distance measure and Ward's
method for linking groups (McCune and Mefford, 1997).