ALTITUDINAL ANALYSES OF LIMESTONE VEGETATION AT … analyses... · ALTITUDINAL ANALYSES OF LIMESTONE VEGETATION AT GUNUNG API, GUNUNG MULU NATIONAL PARK, MIRI, SARAWAK P. KHIDMAT

ALTITUDINAL ANALYSES OF LIMESTONE VEGETATION AT GUNUNG API, GUNUNG MULU NATIONAL PARK,

MIRI, SARAWAK

Julaihi Bin Abdullah

Lai Chau Jian

Master of Science (Plant Ecophysiology)

2004

Pusat Khidmat Makiumat Akademik UNiVERSi77 MALAYSIA SARAWAK

ALTITUDINAL ANALYSES OF LIMESTONE VEGETATION AT GUNUNG API, GUNUNG MULU NATIONAL PARK,

MIRI, SARAWAK P. KHIDMAT MAKLUMAT AKADEMIK

11111 iiiililliIuin 1000246231

JULAIHI BIN ABDULLAH

LAI CHAU JIAN

A thesis submitted in full fulfillment of the requirements for the degree of Master of Science

Faculty of Resource Science and Technology UNIVERSITI MALAYSIA SARAWAK

2004

ACKNOWLEDGEMENTS

The completion of this project reflects the concerted efforts of many people to whom I would

like to express my deepest appreciation. First, I would like to thank Dr Isa Ipor and Dr Cheksum

Tawan, supervisors for my project in giving me all the support, advices and guidance throughout this

study. Secondly, to the Director of Forests Sarawak, Datu Cheong Ek Choon; Senior Assistant

Director (Research), Tuan Abang Haji Abdul Hamid Karim and Ms Lucy Chong, thank you for your

support.

Many thanks to my colleagues in Botany Unit, Forest Research Centre and Botanical

Research Centre, Semengoh for their assistance while conducting the field trips and preparation of

specimens in the herbarium. I would like to extend my sincere thanks to ARO Jemree Bin Hj Sabli for

assisting me in plant identification and establishment of studied plots, SFO Sia Puon Chiew and RO

Jong Lip Khiong for assistance in statistical analysis. Thanks to FR Yahud Bin Hj Wat, FG Banyeng

Anak Ludong, FM Jegong Anak Suka, tree climbers and many general assistants from Forest

Research Centre and Botanical Research Centre as well as staff of Gunung Mulu National Park for all

their assistance. I would like to extend my gratitude to Drainage and Irrigation Department, Kuching

in providing me with the rainfall data and Senior Chemist Madam Chin Siew Phin and her staff in

Agriculture Research Centre for the soil analysis.

My special thanks to my wife, Rosejanawati Ali for her moral support, encouragement and

computing work. Thanks to my son, Azlan and daughter Azie for their love and support. Lastly, I

would like to extend my deepest gratitude to all those who have rendered their support and assistance

to me throughout this study.

Julaihi Abdullah

2004

11

TABLE OF CONTENTS

Acknowledgement Table of contents List of Tables List of Figures List of Appendices Abstracts

Chapter 1 GENERAL INTRODUCTION 1.1 Introduction 1.2 Statement of problems 1.3 Objectives of study

Chapter 2

2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 2.11.1 2.11.2 2.11.3

LITERATURE REVIEW 2.1 Tropical rainforest

Flora Plant population and distribution at different altitudinal levels Forest biomass Soil-vegetation relationship Limestone flora Limestone hill habitats Topography and Edaphic condition Calcifuge and calcicole habit of plants Conservation of limestone flora Background of Gunung Api Location and topography of studied plots at Gunung Api Geological characteristics Climate

Page ii iii vi ix xii xiii

1 3 4

5 5 6 7 8 10 13 18 21 22 23 23 27 27

Chapter 3 ALTITUDINAL INFLUENCE ON FLORISTIC STRUCTURE AND COMPOSITION OF TREES AT GUNUNG API 3.1 Introduction 29 3.2 Materials and methods 29 3.2.1 Sampling methods 29 3.2.2 Species dominance and import value analysis 30 3.2.3 Shannon and Simpson's diversity indices 31 3.2.4 Data analysis 31 3.3 Results and discussion 32 3.3.1 General vegetation 32 3.3.1.1 Lowland limestone forest 32 3.3.1.2 Lower montane limestone forest 33 3.3.2 Floristic composition of trees with d. b. h. ?5 cm at Gunung 34

Api 3.3.2.1 General floristic composition at Gunung Api 34

TABLES OF CONTENTS

Page 3.3.2.2 Stem distribution of tree families at Gunung Api 34 3.3.2.3 Species distribution of trees at Gunung Api 37 3.3.3 Distribution of trees by diameter class at Gunung Api 39 3.3.4 Distribution of trees by height class At Gunung Api 41 3.3.5 Species dominance and important value analysis 44 3.3.5.1 Species dominance within all studied plots 47 3.3.6 Species dominance of trees at different altitudinal levels at 49

Gunung Api 3.3.7 Shannon and Simpson's diversity indices 74 3.3.8 Data analysis 76 3.3.8.1 Cluster analysis for species of trees with d. b. h. ?5 cm within 76

all plots at Gunung Api

Chapter 4 ESTIMATED ABOVE GROUND BIOMASS OF TREES WITH D. B. H. 5 CM AT DIFFERENT ALTITUDINAL LEVELS AT GUNUNG API 4.1 Introduction 78 4.2 Materials and methods 79 4.2.1 Biomass estimation for trees with d. b. h. ?5 cm 79 4.3 Results and discussion 79 4.3.1 Total above ground biomass of trees 79 4.3.2 Basal area of trees 83 4.3.3 Leaf area index of trees 85

Chapter 5 SPECIES RICHNESS AND COMPOSITION OF GROUND FLORA AT DIFFERENT ALTITUDINAL LEVELS AT GUNUNG API 5.1 Introduction 87 5.2 Materials and methods 87 5.2.1 Sampling methods 87 5.2.2 Summed dominance ration (SDR) of ground flora 88 5.3 Results and discussion 89 5.3.1 General floristic composition of ground flora 89 5.3.2 Distribution of individuals of ground flora at different 91

altitudinal levels at Gunung Api 5.3.3 Distribution of families of ground flora at different altitudinal 92

levels at Gunung Api 5.3.4 Distribution of species of ground flora at different altitudinal 92

levels at Gunung Api 5.3.5 Summed dominance ration of ground flora 94 5.3.5.1 Overall summed dominance ratio 94 5.3.5.2 Summed dominance ratio of ground flora at each elevation 95 5.3.6 Total above ground biomass of ground flora at Gunung Api 102 5.3.7 Cluster analysis of ground flora at Gunung Api 103

iv

Pusat Khidmat Makiumat Akademik UNIVERSITI MALAYSIA SARAWAK

TABLES OF CONTENTS

Chapter 6 SOIL-VEGETATION RELATIONSHIP AT DIFFERENT ALTITUDINAL LEVELS AT GUNUNG API 6.1 Introduction 6.2 Materials and methods 6.2.1 Organic carbon 6.2.2 Nitrogen 6.2.3 CEC (K, Ca, Na and Mg) and % Base Saturation 6.2.4 Available phosphorus (P) 6.2.5 Moisture content and pH 6.2.6 Data analysis 6.3 Results and discussion 6.3.1 Soil analysis 6.3.1.1 Percentage of organic carbon 6.3.1.2 Percentage of nitrogen content 6.3.1.3 Pattern of micro-nutrient content 6.3.1.4 Cation exchange capacity 6.3.1.5 Total phosphorus content 6.3.1.6 Mean pH of soils 6.3.1.7 Iron, copper and zinc content 6.3.2 Data analysis of soils 6.3.2.1 Descriptive analysis for soils 6.3.2.2 Cluster analysis for soil characters 6.3.2.3 Correlation of soil characteristics

Chapter 7

Chapter 8

Bibiography Appendices Plates

7.2.2 7.3 7.4 7.5

GENERAL DISCUSSION 7.1 Introduction 7.2 Total flora of Gunung Api 7.2.1 Floristic composition

7.6

7.7

Density of plants at different altitudinal levels at Gunung Api Species endemism at Gunung Api Very rare, uncommon and common species Associations between species distribution and characteristics

Page

106 106 107 108 108 110 110 111 112 112 112 113 114 117 118 119 119 121 121 122 123

125 125 125 127 129 134

soil 135

Analysis on soil variables, correlation matrix of soil variables and altitude; altitudinal variation of vegetation and soils at Gunung Api Forest zonation at different altitudinal levels at Gunung Api

CONCLUSION

136

139

143

145 157 236

V

LIST OF TABLES

Table Title Page

2.1 Details of location, forest types and topography of studies plot 26

3.1 Distribution of families, genera, species, number of trees and density per hectare 34 for trees with d. b. h. cm at different altitudinal levels at Gunung Api

3.2 Sixteen most common families of tree with d. b. h. ?5 cm from 46 families 35 recorded within all plots at Gunung Api

3.3 Distribution of individual trees with d. b. h. ?5 cm by families from 46 families 35 recorded at different altitudinal levels at Gunung Api

3.4 List of 10 most common species found within all plots at Gunung Api 38

3.5 Distribution of trees by height class recorded at different altitudinal levels at 42 Gunung Api

3.6 The relative frequency (Rf), relative density (Rd), relative dominance (RD) and 45 important value (IV) of trees with d. b. h. cm within all studied plots at Gunung Api

3.7 The relative frequency (Rf), relative density (Rd), relative dominance (RD) and 50 important value (IV) of trees with d. b. h. >_5 cm at 130 m a. s. l. at Gunung Api

3.8 The relative frequency (Rf), relative density (Rd), relative dominance (RD) and 53 important value (IV) of trees with d. b. h. ?5 cm at 230 in a. s. l. at Gunung Api

3.9 The relative frequency (Rf), relative density (Rd), relative dominance (RD) and 56 important value (IV) of trees with d. b. h. cm at 330 m a. s. 1. at Gunung Api

3.10 The relative frequency (Rf), relative density (Rd), relative dominance (RD) and 58 important value (IV) of trees with d. b. h. cm at 430 m a. s. l. at Gunung Api

3.11 The relative frequency (Rf), relative density (Rd), relative dominance (RD) and 60 important value (IV) of trees with d. b. h. cm at 530 m a. s. l. at Gunung Api

3.12 The relative frequency (Rf), relative density (Rd), relative dominance (RD) and 62 important value (IV) of trees with d. b. h. cm at 630 in a. s. l. at Gunung Api

3.13 The relative frequency (Rf), relative density (Rd), relative dominance (RD) and 65 important value (IV) of trees with d. b. h. >_5 cm at 730 m a. s. 1. at Gunung Api

3.14 The relative frequency (Rf), relative density (Rd), relative dominance (RD) and 67 important value (IV) of trees with d. b. h. Z cm at 830 m a. s. l. at Gunung Api

3.15 The relative frequency (Rfl, relative density (Rd), relative dominance (RD) and 69 important value (IV) of trees with d. b. h. cm at 930 m a. s. l. at Gunung Api

V1

Table Title Page

3.16 The relative frequency (Rf), relative density (Rd), relative dominance (RD) and 72 important value (IV) of trees with d. b. h. ? _5 cm at 1030 m a. s. l. at Gunung Api

3.17 The relative frequency (Rf), relative density (Rd), relative dominance (RD) and 74 important value (IV) of trees with d. b. h. ?5 cm at 1130 m a. s. l. at Gunung Api

3.18 Number of clusters, similarity level, distance level for trees with d. b. h. z5 cm 76

within all studied plots at Gunung Api

4.1 List of ten families with the highest TAGB for trees with d. b. h. cm within all 81 studied plots at Gunung Api

4.2 List of ten species with the highest TAGB for trees with d. b. h. cm within all 82 studied plots at Gunung Api

4.3 List of ten families with the highest basal area (BA) for trees with d. b. h. ?5 cm 84 within all studied plots at Gunung Api

4.4 List of ten species with the highest basal area (BA) for trees with d. b. h. >-5 cm 84

within all studied plots at Gunung Api

4.5 List of ten families with the highest leaf area index (LAI) for trees with d. b. h. ?5 86

cm within all studied plots at Gunung Api

4.6 List of ten species with the highest leaf area index (LAI) for trees with d. b. h. ?5 86 cm within all studied plots at Gunung Api

5.1 List of ground flora enumerated at Gunung Api based on plant habits within all 89

quadrats at Gunung Api

5.2 List of 18 most common families, genera, species and individuals of ground flora 90 within all quadrats at Gunung Api

5.3 Relative density (Rd), relative frequency (Rf), important value (IV) and summed 94 dominance ratio (SDR) of 20 most dominant species of ground flora within all quadrats at Gunung Api

5.4 Summed dominance ratio (SDR) and number of species of ground flora within 95

all quadrats based on plant hahits at Gunung Api

5.5 List of the most dominant species of plants based on SDR values at each 96 altitudinal level at Gunung Api

5.6 List of ten most dominant species of ground flora at 130 in a. s. l. at Gunung Api 96

5.7 List of ten most dominant species of ground flora at 230 m a. s. l. at Gunung Api 97

5.8 List of ten most dominant species of ground flora at 330 in a. s. l. at Gunung Api 97


vii

Table Title Page








5.17 Number of clusters, similarity level, distance level for ground flora within all 103

quadrats at different altitudinal levels at Gunung Api

6.1 Descriptive analysis for soil characteristics at Gunung Api 121

6.2 Number of clusters, similarity level, distance level for soil characteristics within 122

all quadrats at different altitudinal levels at Gunung Api

6.3 Correlation coefficient of soil characteristics at Gunung Api 124

7.1 Classification of limestone flora within all studied plots at Gunung Api 126

7.2 Species endemic to limestone forest in Sarawak 130

7.3 New records on limestone forest in Sarawak 131

7.4 Very, rare, uncommon and common species recorded in Gunung Api 134

7.5 Principal component matrix of soil variables at Gunung Api 137

7.6 Correlation matrix of soil variables and altitudes at Gunung Api 138

7.7 Altitudinal variation of vegetation and soils at Gunung Api 139

viii

LIST OF FIGURES

Figure Title Page

2.1 Distribution of limestone hills in Sarawak 15

2.2 Locality map of Gunung Api, Gunung Mulu National Park 24

2.3 Topography and location of studied plots at Gunung Api 25

2.4 Cross section through the Melinau Valley and Gunung Api 26

2.5 Mean monthly rainfall in Long Pala and Long Terawan from 1990 - 1991 28

3.1 Percentage of trees by diameter class distribution at all plots recorded at 39 Gunung Api

3.2 Distribution of trees by diameter class at different altitudinal levels at Gunung 39 Api

3.3 Mean diameter of trees at different altitudinal levels at Gunung Api 41

3.4 Percentage of distribution of trees by height class recorded within all studied 42

plots at Gunung Api

3.5 Mean height of trees by different altitudinal levels recorded within all studied 43

plots at Gunung Api

3.6 Forest profile diagram (20 x 7.5 m) of trees at 130 m a. s. l. 51










ix

Figure Title Page


3.17 Shannon and Simpsons' index of diversity 74

3.18 Hierarchical cluster analysis of trees with d. b. h. cm at different altitudinal 77 levels at Gunung Api

4.1 The pattern of total above ground biomass (TAGB) for trees with d. b. h. ý5 cm 80

within all plots at different altitudinal levels at Gunung Api

4.2 The pattern of basal area (BA) for trees with d. b. h. cm within all plots at 83 different altitudinal levels at Gunung Api

4.3 The pattern of leaf area index (LAI) for trees with d. b. h. ?5 cm within all 85

studied plots at different altitudinal levels at Gunung Api

5.1 Distribution of number of individuals of ground flora at different altitudinal 91 levels within all quadrats at Gunung Api

5.2 Distribution of number of families of ground flora at different altitudinal levels 92

within all quadrats at Gunung Api

5.3 Distribution of number of species of ground flora at different altitudinal levels 93

within all quadrats at Gunung Api

5.4 The estimated total above ground biomass of ground flora at different 102 altitudinal levels at Gunung Api

5.5 Hierarchical cluster analysis of ground flora at different altitudinal levels at 104 Gunung Api

6.1 Percentage of organic carbon in soils at different attitudinal levels at Gunung 113 Api

6.2 Percentage of nitrogen content in soils at different altitudinal levels at Gunung 114 Api

6.3 Pattern of calcium content in soils at different altitudinal levels at Gunung Api 115

6.4 Pattern of calcium content in soils at different altitudinal levels at Gunung Api 115

6.5 Pattern of potassium content in soils at different altitudinal levels at Gunung 116 Api

6.6 Pattern of sodium content in soils at different altitudinal levels at Gunung Api 117

X

Figure Title Page

6.7 Pattern of cation exchange capacity (CEC) in soils at different altitudinal levels 117

at Gunung Api

6.8 Pattern of total phosphorus content in soils at different altitudinal levels at 118 Gunung Api

6.9 Pattern of mean pH of soils at different altitudinal levels at Gunung Api 119

6.10 Pattern of iron (Fe) content in soils at different altitudinal levels at Gunung Api 120

6.11 Pattern of copper content (ppm) in soils at different altitudinal levels at 120 Gunung Api

6.12 Pattern of zinc content in soils at different altitudinal levels at Gunung Api 121

6.13 Hierarchical cluster analysis of soil characteristics at different altitudinal levels 122

at Gunung Api

7.1 Temperature recorded at 130 m, 630 m, and 1130 m a. s. 1. at Gunung Api 140

7.2 Humidity recorded at 130 m, 630 m, and 1130 m a. s. 1. at Gunung Api 141

X1

LIST OF APPENDICES

Appendix Title Page

A Distribution of species of trees with d. b. h. cm at different altitudinal 157 levels at Gunung Api

B Total above ground biomass (TAGB), leaf area index (LAI) and basal area 164 (BA) of trees with d. b. h. ?5 cm by families within all studied plots at Gunung Api

C Total above ground biomass (TAGB), leaf area index (LAI) and basal area 166 (BA) of tree with d. b. h. ?5 cm by species within all studied plots at Gunung Api

D Distribution of families, species and number of individuals of ground flora 174

at different altitudinal levels at Gunung Api

E Number of individuals of ground flora for each family at different 186

altitudinal levels at Gunung Api

F Distribution of ground flora by species at different altitudinal levels at 189 Gunung Api

G Relative density (Rd), relative frequency (Rt) and summed dominance 201

ratio (SDR) of ground flora within all quadrats at Gunung Api

H Distribution of total flora at Gunung Api based on Sarawak Herbarium 209

records

I Scatter plots of soil characteristics against altitude at Gunung Api 224

J Very rare, rare, uncommon and common species of plants recorded in 225 Gunung Api

xii

ABSTRACT

The study on floristic composition, total above ground biomass and species dominance of

trees with d. b. h. >_5 cm and ground flora was conducted at 100 in intervals from 130 in to 1130 m

a. s. l. at Gunung Api, Gunung Mulu National Park, Sarawak. A total of 419 species belonging to 243

genera and 93 families were recorded. Of these total, 1103 trees with d. b. h. ?5 cm were enumerated

in an accumulative area of 1.04 ha, belonging to 195 species from 108 genera and 45 families. The

ground flora has higher diversity in which 4953 individuals were enumerated in an accumulative area

of 0.28 ha consisting of 340 species from 211 genera and 84 families. The mean density of trees with

d. b. h. >_5 cm is 940 trees ha' with a total above ground biomass of 264 ton ha-', basal area (BA) of

31.37 m2 ha-' and leaf area index (LAI) of 3.93 ha ha-1. Within all studied plots, Euphorbiaceae has

the most number of trees recorded followed by Dipterocarpaceae and Myrtaceae. Hopea andersonii is

the most dominant tree species with importance value (IV) of 20.49, relative density (Rd) of 5.17,

relative frequency (Rf) of 4.28 and relative basal coverage (RD) of 11.05. This is followed by

Brownlowia glabrata (IV = 14.07) and Cleistanthus myrianthus (IV = 13.89). Plots at 130 in are the

most diverse with 43 species, 37 genera and 25 families whereas plots at 330 in were recorded with

the most number of trees. 79.06% of the trees enumerated are having d. b. h. of below 20 cm. The total

above ground biomass of trees with d. b. h. >_5 cm decreases as altitude increases. For ground flora,

Rubiaceae is the most common diverse family, followed by Euphorbiaceae and Orchidaceae. The

most dominant species of ground flora are seedlings of Cleistanthus myrianthus with summed

dominance ratio (SRD) of 3.01, followed by Hopea cernua (2.98) and the herb Elastostema

variolaminosum (2.63). The total above ground biomass of ground flora is 22.32 ton ha"'. Forty one

(41) species (9.79%) of the total flora enumerated are endemic to limestone forest in Sarawak. Eight

species enumerated in Gunung Api are very rare species as they are recorded only once in a single

location. One hundred and thirteen (113) new records in limestone forest in Sarawak were identified.

The characteristics of soils and their influence on biomass and floristic composition at every

altitudinal level were also discussed. Results of the study show that limestone forest of Gunung Api is

xiii

indeed very rich in species and many species are confined to limestone habitats. The result also

showed that pH, nitrogen, calcium and magnesium are highly correlated with altitude.

xiv

ABSTRAK

Kajian ke alas komposisi flora, jumlah biomassa dan kedominan spesies pokok berdiameter z

5 cm serta tumbuhan herba telah dijalankan pada paras ketinggian setiap 100 m dari 130 m hingga

1130 m di alas paras laut, di Gunung Api, Taman Negara Gunung Mulu, Sarawak. Sejumlah 419

spesies dari 243 genera dan 93 famili telah dicatatkan. Ia terdiri daripada 195 spesies, 108 genera

dan 45 famili daripada 1103 pokok berdiameter >_5 cm dalam jumlah keluasan 1.4 ha dan 340

species, 211 genera, 84 famili daripada 4953 individu tumbuhan herba dalam 0.28 ha. Densiti purata

pokok berdiameter >_5 cm adalah 940 pokok hä' dengan jumlah biomassa sebanyak 264 ton hci',

luas pangkal pokok 31.57 ma hä' dan indeks luas daun sejumlah 3.93 ha ha-'. Euphorbiaceae

merupakan famili pokok yang mempunyai jumlah bilangan pokok yang tertinggi, diikuti oleh

Dipterocarpaceae dan Myrtaceae. Hopea andersonii adalah spesies pokok yang paling dominan

dengan nilai kepentingan berjumlah 20.49, densiti relatif 5.17, frekuensi relatif 4.28 dan luas pangkal

pokok relatif 11.05. Ia diikuti oleh Brownlowia glabrata dan Cleistanthus myrianthus. Plot kajian

yang paling berbeza daripada segi bilangan spesies ialah pada paras 130 m. Sebanyak 43 spesies, 37

genera dan 25 famili dicatatkan di situ sementara plot kajian yang mencatatkan jumlah bilangan

pokok yang terbanyak ialah pada paras 330 m. 79.06% daripada jumlah bilangan pokok yang dikaji

mempunyai diameter pada paras dada kurang daripada 20 cm. Jumlah biomassa pokok berdiameter

>_5 cm menurun apabila ketinggian altitud meningkat. Untuk tumbuhan herba, famili yang paling

berbeza daripada segi spesies ialah Rubiaceae, diikuti dengan Euphorbiaceae dan Orchidaceae.

Spesies yang paling dominan ialah Cleistanthus myrianthus dengan nilai jumlah nisbah dominan

sebanyak 3.01, diikuti dengan Hopea cernua (2.98) dan Elastostema variolaminosum (2.63). Jumlah

biomassa tumbuhan herba adalah sebanyak 22.32 ton hci'. Empat puluh satu (41) spesies atau 9.79%

daripada jumlah keseluruhan tumbuhan yang dikaji adalah tumbuh endemik di hutan batu kapur di

Sarawak. Lapan (8) spesies merupakan tumbuhan jarang dijumpai dan mereka hanya ditemui sekali

sahaja di sepanjang tempoh kajian. Satu ratus tiga belas (113) spesies adalah rekod baru bagi hutan

batu kapur di Sarawak. Sifat-sifat tanah dan kesannya ke alas biomassa dan komposisi flora pada

xv

setiap paras ketinggian plot kajian juga dibincangkan. Keputusan kajian menunjukkan bahawa hutan

batu kapur sememangnya sangat kaya daripada segi kandungan spesies dan kebanyakkan spesies

tersebut hanya terhad di hutan batu kapur di Gunung Api. Kandungan pH, kalsium, magnesium dan

nitrogen adalah berkorelasi tinggi dengan ketinggian di atas paras laut. Pada keseluruhannya, kajian

ini menunjukkan bahawa perbezaan daripada segi paras ketinggian di atas paras laut telah

menyebabkan perbezaan dalam komposisi spesies, struktur hutan dan biomassa hutan batu kapur.

xvi

CHAPTER 1

GENERAL INTRODUCTION

1.1 Introduction

Sarawak is the largest state in Malaysia and is 70% covered by forests. The eight major forest

types found in Sarawak are mixed dipterocarp forest, peat swamp forest, heath forest, alluvial forest,

beach forest, mangrove forest, limestone forest and montane forest. Limestone forest is one of the

major forest types. However, the floristic composition and ecology of limestone forest is the least

understood. In the past years, emphasis has been on other forest types which are timber production

areas such as dipterocarp forest, heath forest and peat swamp forest.

Although the area cover by limestone forest is relatively small, it is of wide occurrence

forming only shallow lenses outcropping between non-calcareous rocks. The limestone forms

characteristic precipitous hills which are such as striking feature of the landscape. Many of the

limestone hills are found from Bau to Tebakang, Niah and the Melinau massif in Mulu. The higher

hills in West Sarawak range from 300 in and 600 in a. s. l. Bukit Bra'ang (750 m) is the only hill that

exceeds 600 in in west Sarawak. The large limestone massif in the Melinau, on the boundary between

Miri and Limbang divisions, reaches a much higher altitude. The twin peaks of Gunung Api and

Benarat exceed 1600 in.

The limestone flora is rich in species. Many are endemics or are species that are associated

with or near the limestone habitat. In Peninsular Malaysia, the limestone flora comprises 1216 species

of which 261 are endemic to Peninsula Malaysia and 130 are confined to limestone (Kiew, 1991). The

flora of limestone is distinct from that of the lowlands, mountains or heath forest not only in its

appearance but also in its species composition. The richness of the flora is in part due to the variety of

microhabitats that limestone hills provide within a very confined area.

In Sarawak, the limestone flora is relatively unknown. A project to study the vegetation of the

limestone hills of Sarawak was included in the Forest Research Programme of the Forest Department,

Sarawak in 1960's. The project, however, had a low priority. Anderson (1965) in a brief account

1

mentioned that 600 species had been recorded from limestone. His account concentrated on the Bau

limestone. In 1970's the Royal Geographical Society and the Forest Department Sarawak collected

many species of plant during the expedition in conjunction with the gazettment of the Gunung Mulu

National Park in 1974. Plant collecting on Gunung Api and Gunung Benarat in the Gunung Mulu

National Park has led to the discovery of many species endemic to the hills. Anderson and Chai

(1982) describe the mature limestone flora between 800 m and 1,700 m. From 1980's to the present,

many collection trips had been organized to collect limestone flora throughout Sarawak by the Forest

Department of Sarawak. The specimens are kept in the Sarawak Herbarium. Recently, a project

entitled "The limestone flora of Sarawak concentrating on limestone orchids" funded by

Intensification of Research in Priority Area (IRPA) was completed. In addition, the Sarawak

Biodiversity Centre is currently carrying out study on limestone hills in Bau and a number of students

from local universities are conducting their projects in Bau and Padawan.

However, the ecology of limestone flora has not yet been studied (Kiew, 1991). In Sarawak,

Proctor et al. (1983) conducted ecological studies at lower altitude of 300 m at Gunung Api. They

conducted ecological study in four contrasting lowland rain forest in Gunung Mulu National Park.

The study was restricted at the base of cliff and ravines at a single elevation at Gunung Api. To date

no study has been done on the enumeration of limestone forest at different altitudinal levels especially

in Sarawak.

1.2 Statement of problems

It is a known fact that the limestone flora is exceptionally rich and many species are endemics

or are species that are not found away from limestone. The richness of the flora is in part due to the

variety of the microhabitats that limestone hills provide within a very confined area. The limestone

flora is particularly vulnerable because it occupies a relatively small area compared to other types of

forests. The vegetation on limestone hills particularly those in Bau has been seriously disturbed in

the past years. Gold and antimony deposits, associated with intrusive rocks have been mined for at

2

least a hundred years. Due to fast pace of development, many limestone hills have been threatened or

destroyed by quarrying and other land development. Many species of limestone flora are threatened

due to their potential in horticulture industry. Limestone orchids, pitcher plants, gesneriads, aroids,

gingers, palms, ferns and other herbaceous plants are constantly threatened by wild plant collectors.

Many species are in danger of extinction as they are local endemics. Some examples are the slipper

orchids of Paphiopedilum sanderianum, P. stonei, P. lowii, jewel orchids of Macodes and Dossiana

spp. as well as Nepenthes northiana.

To date, studies on the limestone flora in Malaysia has been on three major categories. They

are the floristic, ecology and the conservation of limestone flora. Various authors have also pointed

out that the diversity of habitat on limestone hills has contributed to the rich flora and it has been

long been believed that the variation due to topography aspects, drainage, light, humidity act

interdependently to create the diverse habitat (Henderson, 1939; Chin, 1977, Wycherley, 1971;

Anderson, 1965; Kiew, 1991). Much of these variations are not studied in depth and systematically.

In Sarawak there is no correlation study on the environmental variables and species composition on

limestone forest formation. The result of this study is important so that guidelines and policies on

limestone flora management and conservation can be established.

Floristic composition at different altitudinal levels has been conducted in sandstone hills by

Martin (1977) in west ridge of Gunung Mulu and Layang (1997) in Gunung Santubong in Sarawak.

Although Gunung Api is a perfect site to conduct similar study, no effort was made in the past. Part

of the reasons is it is difficult to climb as it takes 4 to 5 hours to reach the summit of Gunung Api and

unavailability of water resources for camping. Establishment of ecological plots is an extremely

tough challenge as one has to climb the mountain everyday to conduct the study.

There is an urgent need to study the limestone flora in Sarawak in order to gather

information on species richness, diversity and conservation status of limestone forest. More

importantly, ecology data is needed to fully understand the relationship of species composition with

3

the environmental variables. The incorporation of floristic data and ecological data will provide a

useful guide in forming a strategy for the association of limestone flora and its habitat.

Gunung Api is located in Gunung Mulu National park. The Park is inscribed as World

Heritage Site in 2000. Gunung Api is chosen for the study as it is the highest limestone hill between

Northern Thailand and New Guinea from 130 in to 1600 in a. s. l. thus the most suitable site to conduct

field survey. Gunung Api also has the most spectacular pinnacles at its summit which is a popular

tourism attraction. The result of this study will be useful for the understanding conservation of the

limestone flora and provide important information for sustainable management of our forests.

1.3 Objectives of study

The objectives of the present study are: -

(i) To determine the floristic composition, species richness, total above ground biomass, species

dominance and important value, basal area and leaf area index for trees with d. b. h. >_5 cm at

different altitudinal levels of Gunung Api.

(ii) To study the species composition, distribution, important value, summed dominance ratio and

total above ground biomass of herbaceous plants or ground flora at different altitudinal levels

of Gunung Api.

(iii) To study the characteristics of soils and their influence on floristic composition and forest

structure at different altitudinal levels.

(iv) To identify endemic and rare species at Gunung Api for formulation of conservation strategy.

4

Pusat Khidmat Makiumat Akademik UNIVERSITI MALAYSIA SARAWAK

CHAPTER 2

LITERATURE REVIEW

2.1 Tropical rainforest

Tropical rain forest (Tropische Regenirwald) is a term created by A. F. W. Schimper in his

great classic work plant geography and has been generally used ever since. It describes the forests of

the ever-wet tropics where there is no, or only minimal, seasonal water shortage. Schimper, 1903 (in

Whitmore, 1984) gave a brief diagnosis of dry-land tropical rain forest, that it is evergreen,

hygrophilous in character, at least thirty meters high, rich in thick-stemmed lianas, and in woody as

well as herbaceous epiphytes.

The world's rain forests occur in three main blocks. The most extensive is the American rain

forest, centered on the Amazon Basin, extending to parts of the shores and islands of the Caribbean in

the north and down the eastern Andean foothills in the south, to the western slopes of the Andes and

the Atlantic coast mountain. It comprises about half of the total area of forest of the world of about 4

million km2 (Whitmore, 1984). South East Asia has approximately 2.5 million km2 centered on the

Malay Archipelago and extending to continental Asia as far as Sri Lanka and India, and into

Australia, Melanesia, and Polynesia (Whitmore, 1984). The Malesian phytogeographical zone

consists of an area of extending from Peninsular Thailand in the north-west to Papua New Guinea and

adjacent islands in the southeast. It occupies a total land area of approximately 3 million km2. The

smallest rain forest region is in central African areas with some extension westward along the shores

of the Gulf of Guinea (Whitmore, 1984).

2.2 Flora

The flora of Malesia is exceedingly rich, and is conservatively estimated to comprise 25,000

species of flowering plants (van Steenis, 1972) which is about 10 per cent of the world's flora. Some

40 per cent of the genera in Malesia are endemic and so are still more of the species. The biggest

family is the Orchidaceae with 3000 to 4000 species. Amongst the woody plants, the

5

Dipterocarpaceae have about 500 species, Eugenia (Myrtaceae) and Ficus (Moraceae) some 500

species each and Ericaceae 737 species (Whitmore 1972,1972a).

The flora of Borneo has been conservatively estimated to comprise 12,000 to 15,000 species

of vascular plants (Merrill, 1950). About 5000 species are endemic to the island. Borneo is the centre

of distribution for the paleotropical Dipterocarpaceae, a family of trees with 262 known species (34%

of which are endemic and 59 species unique to the island). The rich flora occurs from the sea-coasts to

inland mountain ranges.

2.3 Plant population and distribution at different altitudinal levels

General accounts of the altitudinal influence of the tropical rain forest are available in

Richards (1966), Troll (1957) and Grubb and Whitmore (1966). Specific accounts of the Malaysian

region are available in van Steenis (1934), Richards (1936), Wyatt-Smith (1966), Burgess (1965),

Whitmore and Burnham (1969), van Steenis (1972), Whitmore (1972), Proctor et al. (1983) and

Layang (1997).

Based on structure and physiognomy, the forests can be divided into formation types. These

can be further divided into floristic zones according to their floristic composition (Symington, 1943).

The altitudinal zonation of the smaller Malaysian mountains can thus be considered in terms of

formation types and floristic zone.

Structure and floristic change with elevation, giving rise to separate lower montane (elevation

c. 750-1500 m) and upper montane forest (elevation c. ? 1500 m) formations (Whitmore, 1984).

Grubb (1977) has discussed a related phenomenon called the Massenerhebung effect, which as been

described by Proctor et al. (1988,1989) in relation to the summit of Gunung Silam, Sabah.

Decreasing temperatures cannot account for the vegetation changes with elevation because parallel

changes occur at higher elevations on larger, cooler mountains (Proctor et al., 1988).

The distribution of tree species and the changes in composition with elevation have been

studied by Kochummen (1982), and several qualitative accounts exist of mountain vegetation in

6

Peninsular Malaysia such as Gunung Korbu (Mead, 1933), as well as Gunung Benom (Strugnell,

1931; Whitmore, 1972) and Gunung Tahan (Ridley 1915; Strugnell and Mead, 1937; Soepadmo,

1971) within the main range. Other similar studies conducted in Malaysia are Gunung Mandi Angin

in Terengganu (Cockburn, 1969), Bukit Lagong in Selangor (Wyatt-Smith, 1966) and Gunung Ulu

Kali near the state boundary between Selangor and Pahang (Stone, 1981). Pendry and Proctor (1996)

described the cause of elevational zonation of rain forests on Bukit Belalong, Brunei, and Bruijnzeel

et al. (1993) made detailed hydrological studies of the same mountain, concentrating on the zone

between 680 m and 870 m, where tall-structured forest gave way to stunted forest.

2.4 Forest biomass

Forest inventories are the most important source of estimates of woody biomass production.

The biomass volume can be assessed in various ways. For extensive areas of rainforest in the early

stages of management, aerial photographs can provide tolerable estimates of standing volume

(Heinsdijk, 1960; Swellengrebel, 1959; de Rosayro, 1959). In the past, and to a very large extent still,

assessment has been conducted by strip surveys, recording either number of stems of merchantable

species and bole sizes only, or all stems down to a given size, within a given distance of a survey line.

Such assessments can provide considerable data on stand composition and occurrence of forest types,

and is suitably designed can give statistically reliable estimates of volume, as discussed by Dawkins

(1958).

The estimation of forest biomass is normally carried out either by destructive harvest

techniques (Kira, 1969; Latiff et al., 1995; ) or by applying regression equations derived from

destructively harvested trees (Kato et al., 1978), and by using a computerized digital image-

processing system such as the Advanced Very High Resolution Radiometer (AVHRR) which data

were supplied on computer compatible tapes (CCT) from NASA (Millington and Townsend, 1989).

The allometric correlation has been introduced by Research Group on Forest Productivity (1960);

Ogawa and Kira (1977); Yamakura et al. (1986); Brown et al. (1989) to estimate the above ground

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ALTITUDINAL ANALYSES OF LIMESTONE VEGETATION AT … analyses... · ALTITUDINAL ANALYSES OF LIMESTONE VEGETATION AT GUNUNG API, GUNUNG MULU NATIONAL PARK, MIRI, SARAWAK P. KHIDMAT