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
5.9 List of ten most dominant species of ground flora at 430 m a. s. l. at Gunung Api 98
vii
Table Title Page
5.10 List of ten most dominant species of ground flora at 530 m a. s. l. at Gunung Api 98
5.11 List of ten most dominant species of ground flora at 630 m a. s. l. at Gunung Api 99
5.12 List of ten most dominant species of ground flora at 730 m a. s. l. at Gunung Api 99
5.13 List of ten most dominant species of ground flora at 830 m a. s. l. at Gunung Api 100
5.14 List of ten most dominant species of ground flora at 930 m a. s. l. at Gunung Api 100
5.15 List of ten most dominant species of ground flora at 1030 m a. s. l. at Gunung Api 101
5.16 List of ten most dominant species of ground flora at 1130 m a. s. l. at Gunung Api 101
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
3.7 Forest profile diagram (20 x 7.5 m) of trees at 230 m a. s. l. 53
3.8 Forest profile diagram (20 x 7.5 m) of trees at 330 m a. s. l. 55
3.9 Forest profile diagram (20 x 7.5 m) of trees at 430 m a. s. l. 58
3.10 Forest profile diagram (20 x 7.5 m) of trees at 530 m a. s. l. 60
3.11 Forest profile diagram (20 x 7.5 m) of trees at 630 m a. s. l. 62
3.12 Forest profile diagram (20 x 7.5 m) of trees at 730 m a. s. l. 64
3.13 Forest profile diagram (20 x 7.5 m) of trees at 830 m a. s. l. 67
3.14 Forest profile diagram (20 x 7.5 m) of trees at 930 m a. s. l. 69
3.15 Forest profile diagram (10 x 7.5 m) of trees at 1030 m a. s. l. 71
ix
Figure Title Page
3.16 Forest profile diagram (10 x 7.5 m) of trees at 1130 m a. s. l. 73
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
7