SOIL PHYSICOCHEMICAL PROPERTIES AFTER ESTABLISHMENT OF OIL PALM PLANTATION IN PEAT SWAMP FORESTS AT MUKAH,

SARAWAK

Zulfaqar bin Sa'adi

S Master of Environmental Science .598

(Land Use and Water Resource Managment) Z94 20112011

Pusat Kbidmat MakJumlit AJcad mi RSm MALAY, fA . R W. •

P.KHIDMAT MAKLUMAT AKADEMIK UNIMAI

1111111111111111111111111 1000246267

SOIL PHYSICOCHEMICAL PROPERTIES AFTER ESTABLISHMENT OF OIL PALM PLANTATION IN PEAT SWAMP FORESTS AT MUKAH, SARA W AK

ZULFAQAR BIN SA'ADI

A dissertation submitted in partial fulfillment of the requirements for the degree of Master of Environmental Science

(Land Use and Water Resource Management)

Faculty of Resource Science and Technology UNIVERSITI MALAYSIA SARA W AK

2011

DECLARATION

No portion of the work referred to in this description has been submitted in support of an

application for other masters of qualification of this and any other university or

institution ofhigher learning.

Zulfaqar bin Sa'adi

Masters of Enviromnental Science

(Land Uses and Water Resource Management)

Faculty of Resource science and technology

Universiti Malaysia Sarawak

APPROVAL SHEET

Name of candidate: Zulfaqar bin Sa'adi

Title of dissertation: Soil physicochemical properties after establishment of oil

palm plantation in Peat Swamp Forests at Mukah, Sarawak

.'

Dr Mohd Effendi Wasli

Supervisor

ACKNOWLEDGMENTS

Firstly, I would like to thank Allah for His blessing upon me to complete my

project. Besides, special thanks go to Dr Mohd Effendi Wasli as Supervisor for his full

encouragement, guidance, supervision and professionalism. Furthermore, Thanks also to

our lab assistants, for their materials provided, patience and helps concerning the lab and

equipment preparation. Lastly, to fellow friends and people that involved direct or

indirectly in finishing this project. The author also wishes to thank University Malaysia

Sarawak for equipment, material and financial support .

.'

Pusat Khidmat Maklumat Akademik UNTVERSITI M LAY tA tU VAf<

Contents

LIST OF FIGURE Page

Figure 1: Distribution ofPeat forest in Sarawak (Department of Irrigation and Drainage, Sarawak).......................................... .. ...................................................... 10 Figure 2: Map ofKampung Igan, Mukah, Sarawak and sampling locations (Red dotted: Peat soil sampling sites) .......................................................................................21

Figure 3: Sampling location ......... ........................................................................ .24

Figure 4: Map ofSarawak Land Capability Classification and Evaluation for Agricultural

Crops ofKampung Igan, Mukah (Maas, 1986) .......................................................29

Figure 5: Soil pH under peat swamp forest (PI), 2 years old young oil palm (P2) and mature

oil palm ofmore than 15 years old (P3) ...............................................................38

Figure 6: Soil bulk density under peat swamp forest (PI), 2 years old young oil palm (P2)

and mature oil palm ofmore than 15 years old (PJ) ................ . ............................... 39

Figure 7: Soil porosity under peat swamp forest (PI), 2 years old young oil palm (P2) and

mature oil palm ofmore than 15 years old (P3) ..................................................... .41

Figure 8: Soil water content under peat swamp forest (PI), 2 years old young oil palm (P2)

and mature oil palm ofmore than 15 years old (P3) ..... ... ........................................ .42

Figure 9: Soil hardness ~der peat swamp forest (PI), 2 y€(ars old young oil palm (P2) and

mature oil palm ofmore than 15 years old (P3) ... '; .............................. ... ............... .43

Figure 10: Soil dry matter under peat swamp forest (p 1), 2 years old young oil palm (P2) and

mature oil palm ofmore than 15 years old (P3) ....................................... . ............ .44

Figure 11: Soil moisture content under peat swamp forest (PI), 2 years old young oil palm

(P2) and mature oil palm of more than 15 years old (P3) ................................... . ...... .46

Figure 12: Soil organic matter under peat swamp forest (PI), 2 years old young oil palm (P2)

and mature oil palm ofmore than 15 years old (P3) ..................................... ...... ..... .48

LIST OF TABLE

Table 1: Collection of soil samples from different Sites ............... .... .........................23

Table 2: Summarization of Sarawak Land Capability Classification and Evaluation for

Agricultural Crops ofKampung Igan, Mukah .......................................................31

Table 3: Selected Physicochemical soil properties at oil palm plantation in Kampung Igan,

Mukah Sarawak ..........................................................................................35

. ABSTRACT........ ..... ............................................... ... ............... ....... .................. ...... . 1

ABSTRAK................. .. ............................. ................. .... .. ........ .... ... .... ...................2

CHAPTER 1: INTRODUCTION...... .. ..... .... ........................ ......... ...............................4

CHAPTER 2: LITERATURE REVIEW

Tropical peat swamp forest ........................................ ... ...........................................8

Peat Soils ofSarawak.. ~'............................................ ... . .. ... ............................. 11

Benefits and importance ofpeat swamp forest. ... : .................................................. 12

Effects of human activity in peat swamp forest. ... : ............. ... .. .. ..... . ........ ... ........ .. .. 16

Agricultural development through peat swamp forest in Sarawak.... ................................ .18

CHAPTER 3: MATERIALS AND METHODS

Soil classification of the study area ...................................... .............. . .......... .. ...20

Study area ..................................................................................................20

Sample collection ............. . ..... . .....................................................................23

Laboratory Analyses ........ . .................................................................. ..........24

DeteITIlination of soil physiochemical properties ....................................................25

Soil bulk density, Soil water content and Porosity ...................................................25

Soil pH deteITIlination ...................... . ..... . ........................................................25

Soil dry matter content (DM) .......................................... . ..................... . ..........26

Soil moisture content (MC) ........................................................................... 26

Soil Organic matter content. ......................................... . ...................................27

CHAPTER 4: RESULTS AND DISCUSSION

Capability of the land for agricultural purpose ........................................................28

Suitability and capability of the soil in the study area for agricultural purpose .................34

Compruisons of soil physicochemical properties of oil pahn under various stand ages with

the peat swamp forests ..................................................................................36

Tropical peat swamp forest soil under various form ofland use ........................................... .48

CHAPTER 5: CONCLUSIONS ......................................................... . . .. ... ... ..............52

REFERENCES

APPENDIX

I

Soil physicochemical properties after establishment of oil palm

plantation in peat swamp forests at Mukah, Sarawak

Zulfaqar bin Sa'adi

Masters Environmental Science (Land use and water resource management)

Faculty of Resource science and technology

Universiti Malaysia Sarawak

ABSTRACT

(Soil properties determination is important towards an improvement of both strategy and

techniques for future development of conversion peat swamp forest into oil palm plantation. This

study discusses soil properties of peat swamp forest under oil palm plantation in Kampung Igan,

Mukah, Sarawak. in comparison with the sUlTounding peat swamp forests. Peat soil samples in

this study were collected from peat swamp forest (PI), Ladang Rakyat Pelita Igan Jaya oil palm

plantation for young oil palm plantation of 2 years old (P~) and Felcra Bhd oil palm plantation

for mature oil palm plantation of more than 15 years old (P3)) The size of each experimental plot

was 20 x 20m. Soil samples were collected at 0-25 cm depths at each site. For P2 and P3, soil

samples were collected and differentiate as no fertilizer point and fertilizer point. Undisturbed

cores and bulk samples were collected for analysis of bulk density and moisture content. Soil

1

~~,

physicochemical properties were determined by standard procedures. The findings showed that

PI and P2 classifies as 05gn (peat soil) while P3 was 4fw-05gn (mixed mineral and peat soil).

Soil pH, soil bulk density, water content and soil hardness was increased while soil organic

matter and soil porosity was decreased. Dry matter content and moisture content show

inconsistency between the sites. As the differences between fertilizer point and no fertilizer point

in P2 and P3 showed various trend for each analysis. Results of this study will be useful in

predicting the soil condition trend between ages ofoil palm plantation in various perspectives and

ensure continuous benefits from the development of peat swamp forest especially involving

plantation activities and soil management.

ABSTRAK

Penentuan sifat-sifat tanah dalam penukaran hutan tanah gambut kepada ladang kelapa sawit

penting dalam membangunkan strategi dan teknik untuk pembangunan di masa depan. Kajian ini

membincangkan sifat-sifat tanah di bawah penanaman ladang kelapa sawit oleh syarikat

berasaskan kelapa sawit di Kampung Igan, Mukah, Sarawak, dengan membandingkannya dengan

keadaan semasa hutan tanah gambut di sekitamya. Sampel tanah gambut dalam kajian ini diambil .'

dari hutan tanah gambut (PI), Ladang Rakyat Pelita Igan Jaya untuk kelapa sawit yang masih

mud a iaitu berusia 2 tahun (P2) dan Felcra Bhd untuk kelapa sawit yang sudah matang melebihi

15 tahun (P3). Saiz setiap plot eksperimen ialah 20x20m. Sampel tanah dengan kedalaman 0-25

cm di hutan tanah gambut diambil manakala sampel tanah diambil di kawasan yang tidak dibajai

dan dibajai di P2 dan P3. Fisikokimia tanah ditentukan dengan prosedur standard. Jenis tanah di

2

PI dan P2 diklasifikasikan 05gn (tanah gambut) manakala P3 ialah 4fw-05gn (campuran tanah

mineral dan tanah gambut). PH tanah, isipadu ketumpatan tanah, kandungan air dan kekerasan

tanah bertambah manakala kandungan bahan organik tanah dan keporosan tanah menurun. Bahan

kandungan kering dan kandungan lembapan menunjukkan nilai yang tidak konsisten di setiap

kawasan kajian. Untuk perbezaan antara kawasan yang dibajai dan tidak dibajai menunjukkan

keputusan mengikut kecenderungan yang berlainan bagi setiap analisis. Keputusan daripada

kajian ini berguna dalam menjangka perubahan usia ladang kelapa sawit dari perspektif yang

pelbagai dan memastikan keuntungan berterusan daripada pembangunan hutan tanah gambut

terutama melibatkan aktiviti perladangan dan pengurusan tanah.

3

I

CHAPTER!

INTRODUCTION

Peat is a type of soil that contains a high amount of dead organic matter, mainly plants

that have accumulated naturally over thousands of years . It takes approximately a staggering 10

years for I cm of peat to fonn (DOE, 2011). The thickness of the peat layer varies per location,

but in South-east Asia it can reach up to 25 meters. Dead plants in peatlands are different to other

ecosystems as they do not fully decompose. Micro-organisms such as bacteria and fungi are

prevented from rapidly decomposing the dead plants as the waterlogged conditions reduce the

amount of oxygen in the soil. The factors which cause peat to accumulate may be the same the

world over, but different types of peatlands develop because of differences in climate, soil type

and plant species. Peatlands are found in almost every country in the world. They cover over 4

million km2 worldwide, or 3% of the world's total land area, and represent half of the Earth's

wetland areas (WI, 2007). The largest areas are found in the cold tundra regions of Northern

Russia and Canada, called boreal peatlands while Southeast Asia contains the largest areas of

tropical peatlands. Tropical lowland peatlands were originally covered by dense rainforest (WI,

2007). ..

Peatlands may be naturally forested or naturally open and vegetated with mosses, sedges

or shrubs. Examples of naturally forested peatlands are the Alder peat forests in Europe and the

lowland humid tropical peat swamp forests in Southeast Asia ((Rieley et aI., 1992; Page et aI.,

2006). Tropical peatlands are widely distributed throughout the world. Small tracts are found in

parts ofLatin America, Africa and the Caribbean. The vast majority, however, is found in South­

4

I'u at Khidmat MakJumat Akade,mik UNlVERSnl MALAYSIA SARAwAJ<

east Asia, covering 60% of the total tropical peatland area and over 85% of tropical peatland

carbon storage (WI, 2007). Examples of naturally open peatlands are the permafrost areas of

Russia and Canada, the Everglades in North America, and the high mountain peatlands (Paramos)

ofthe Andes and Himalayas (WI, 2007).

Peat soils often possess nutrient-poor soils, and tend to be the poorest areas for agriculture

which support only low population densities. Despite this, millions of people live in and depend

on the world's peatlands for their livelihoods. These include herding cattle, catching

fish, harvesting reeds, farming, forestry and collection of many valuable non-timber forest

products (WI, 2007). Efforts to improve the agricultural production of peatlands by conversion,

drainage and fertilizing the soils are generally unsuccessful and very unsustainable in the past.

These areas often tum into wastelands within decades where as a result of soil subsidence, they

become prone to long periods of inundation. Many tropical peatlands are underlain by potential

acid sulphate soils which become active when drainage levels become too deep, causing severe

acidification of the area and its surroundings. Drainage also causes significant increase of fire

risks (WI, 2007).

Human exploitation has destroyed 25% of the peatlands on earth. The enormous peatlands

of Northern America 0/ Russia are still relatively unaffcrcted. However in many countries in

Europe and Central Asia peatlands have been severely affected by agriculture and mining (WI,

2007). Even if degraded, decomposition processes in the cold northern peatlands and southern

peatlands of Argentina or Chile take place at a much slower rate than in the tropics. In particular

the magnitude of the loss of the boreal peatlands in Canada or Russia is enormous. If these are

degraded, global greenhouse gas emissions would rise dramatically as these areas currently store

5

1

,p

over 50 times more carbon than all annual anthropogenic fossil fuel emissions (WI, 2007). Of

even greater concern is that the threat of climate change on peatlands themselves is alarming and

could forms a vicious circle. Climate change driven by global warming could lead to degradation

of the peatland areas and in tum lead to massive emissions of carbon from the organic peat. In

addition, the combination of relatively young (seasonal) vegetation and temporary flooding leads

in boreal peatlands to production of methane, a very potent greenhouse gas. There is also a risk

that fossilised methane, stored under the permafrost areas, could be released (WI, 2007).

The conservation ofpeatlands is important for a number of reasons including biodiversity,

archaeology, carbon storage and water storage and also because of their landscape value. A

number of measures including Government policy, legislation, protected sites and education are

currently utilized as part of a strategy for the protection ofpeatlands.

This study was conducted at Kampung Igan, Mukah, Sarawak (20 49' 50.82"N, 111 0 41'

17.53"E) (Figure 2), located at the estuary of Batang Igan River in Matu district cover about

244.58 km2• At the inland area of Kampung Igan, consist of large acreage of peat swamp forest.

Peat swamp forest in Kampung Igan was under increasing pressure from development such as

human settlement but agriculture conversion of oil palm plantation, sago plantation and other

agricultural activities was a particular concern. All thi~ development will subsequently arise

various environmental problems especially soil .subsidence in the near future if not manages

properly. Subsidence lowering of ground surface will occurred unavoidably due to compaction

and decomposition of organic material at Kampung Igan as it originally cover mostly by peat

swamp forest. These situations as a result ofmechanization used in agricultural activity cannot be

stopped under drained conditions as effectiveness of the drains decrease but can only be

6

tJc

minimized. In the end, if not manage properly, water management would be more complex and

costly. Drainage system intended to slow down soil subsidence will in the end altered the

topography of the area, thus changing the flow pattern which would increase the occurrence of

flooding. In case ofover drainage, impacts that foreseen to happen such as rate of subsidence and

flooding increase, occurrence of acid-sulphate soils, forest fires, irreversible drying, pest and

tennite attack, nutrient imbalance and low crop yield.

The objectives of this study was to compare physicochemical properties of peat swamp

forest, young oil palm plantations and mature oil palm plantations that were previously peat

swamp forest to determine the effect of forest conversion and changes of peat soil condition

through oil palm development so that the data collected could be used by various stakeholder to

help management practices and improve development techniques which intended to be done at

the area ofpeat swamp forest or originally peat swamp forest.

.'

7

CHAPTER 2

LITERATURE REVIEW

Tropical peat swamp forest

Peatlands may be naturally forested or naturally open and vegetated with mosses, sedges

or shrubs. Examples of naturally forested peatlands are the Alder peat forests in Europe and the

lowland humid tropical peat swamp forests in Southeast Asia (Rieley et aI., 1992; Page et al.,

2006). Tropical peatlands are widely distributed throughout the world. Small tracts are found in

parts of Latin America, Africa and the Caribbean. Most of the world's tropical peatlands (about

62%) are found in the Indo-Malayan region where 80% in Indonesia, 11 % in Malaysia, 6% in

Papua New Guinea, with small pockets and remnants in Brunei, Vietnam, the Philippines and

Thailand (Rieley et aI., 1992; Page et aI., 2006). These peat swamp formations are geologically

recent, mostly <5,000 years old. They largely overlie marine muds and sands in the coastal

lowlands of Peninsula Malaysia, and the islands of Borneo, Sumatra, Papua New Guinea,

Sulawesi and the Moluccas. Some older peat swamps (up to 11,000 years old) overlie riverine

sediments at slightly higher elevations in central Kalimantan in Borneo (Rieley et aI., 1992; Page ",'

et aI., 2006).

Peat swamps forests are an important component of the world's wetlands with the

dynamic link between land and water, a transition zone where the flow of water, the cycling of

nutrients and the energy of the sun combine to produce a unique ecosystem of hydrology, soils,

flora and fauna. The tropical peat swamp forests of the Indo-Malayan region are unusual

8

ecosystems and they differ dramatically from north temperate and boreal peat lands which are

dominated by Sphagnum spp., grasses, sedges and shrubs. Trees in the peat swamp forests can

grow to over 70 m high, despite the extreme conditions of low pH (2.9-4), low nutrients and

anaerobic acidic water regimes with unstable and spongy substrate of peat that may be 20 m deep

or more. The forest floor is flooded during wet seasons, but even during dry seasons the peat

remains waterlogged, with pools amongst the trees. Their continued survival depends on a

naturally high water level that prevents the soil from drying out to expose combustible peat

matter. This harsh waterlogged environment has led to the variation of many species of flora

uniquely adapted to these conditions Borneo (Rieley et aI. , 1992; Page et ai., 2006).

There are about 2.7 million hectares of peat swamps in Malaysia accounting for 8% of the

total area of the country, of which 1.7 million hectares or 63 % are in the deltas and coastal plains

of Sarawak (Rieley et ai. 1992; Page et aI. 2006). Almost all of the peat swamp forests of

Peninsular Malaysia, as in aU the other locations, have been destroyed or degraded over the past

50 years and none remain in a pristine condition. Precise estimates are difficult, but they have

declined from about 1 million ha (Coulter, 1957) to 0.67 million ha in 1981, to 0.34 million ha in

1991 (Rieley et aI. 1996), to 0.30 million ha in 2005 (UNDP, 2006). Since then there has been

further decline and more than half of the remainder is degraded. Only about 100 ha is fully

'protected' in Virgin JUngle Reserve, but this is an ar~a too small to ensure preservation of

ecosystem functioning, since the water table cannot be maintained in its original state. About

67% is now in Permanent Forest Reserves but these are targeted for sustainable logging. The rest

is available for conversion to other land uses. The only large tract of pristine peat swamp forest

remaining on mainland Asia is the Pekan peat swamp forest, in the state of Pahang on the east

coast of the Malaysian peninsula. Despite its high biodiversity and ecosystem value, it has been

9

designated as Production Forest Reserve (i.e. logging is allowed). Small areas of peat swamp

forest also still remain in Sabah, and although significant areas remain in Sarawak, they have

mostly been degraded by logging (Catherine, 2010). Sarawak, the largest state in Malaysia, has

the biggest reserve of peat swamp forest. Peat swamps in Sarawak account for 13% of the State's

total land area. The coastal and riverine area covers about 19% of the state land area. This

includes both the fresh water peat (l.698 million hectares) and mangrove (154,000 hectares)

areas. In general, peat soils are found mostly within the delta and stretching inland along the

riverine of the Samarahan-Sadong, Lupar-S arib as, Rajang, Baram and Limbang river system

(Figure 1).

t 5O\JI'H CHINA SEA

KAlIMANTAN,

Figure 1: Distribution of Peat forest in Sarawak (Department of Irrigation and Drainage, Sarawak)

10

Peat soils of Sarawak

Tie (1979) refers to peat as organic soils on the basis of mass composition i.e. soils that

contain at least 65% organic matter or conversely, less than 35% mineral content. The more

recent definition for organic soils as adopted by the Soil Division of Sarawak is based on profile

partition, i.e. soils that have 50 cm or more organic soil matter within 100 cm or more than twice

that of mineral soil materials overlying bedrock within 50 cm (Teng, 1996).

In Sarawak, the landscape for lowland organic soils ranges from basin swamps to valley

swamps. The morphological characteristics of lowland organic soils are quite similar throughout

the region. The convexity of coastal and deltaic peat swamps surfaces are increasingly

pronounced with distance from the sea (Murtedza et aI., 1992). In the natural state, the water table

is always high, often at or near the surface (fie and Kueh, 1979; Andrieese, 1988; Murtedza et

aI., 1992). In drained areas, the organic soils are transformed to a compact mass consisting of

partially and well-decomposed plant remains with large wood fragments and tree trunks

embedded in it (Murtedza et aI., 1992). Sulfidic marine clay is often found underlying the organic

materials in organic soils (Andriesse, 1964). The common soil profile in drained organic soils

consists of three distinct layer which categories as upper layer (20 - 30 cm thick) consisting of

well-decomposed organic materials of the sapric type, a middle layer (30 - 40 cm thick)

consisting of semi-deco~posed organic materials of the ,hemic type and a lower layer of fibric

materials which is mainly large wood fragments and branches and tree trunks (Murtedza et aI.,

1992).

11

Benefits and importance of peat swamp forest

Peatlands contain globally at least 550 Gigatonnes of carbon equivalent to all other

terrestrial biomass (forests, grass and scrublands', etc.) and twice as much as all carbon stored in

the world's forests. In the sub (polar) zone, peatlands contain on average 3.5 times more carbon

per hectare than above-ground ecosystems on mineral soil, in the boreal zone 7 times more and in

the humid tropics over 10 times the amount of carbon stored in above-ground habitats (WI,

2007).

Due to their capacities to store and maintain large quantities of water, peat swamp forests

play an important role in flood mitigation and ensure a continuous supply of clean water

throughout the year. Mountain peatlands, for example in the Himalayas, Tibetan Plateau and the

Andes, playa crucial role in reducing extremes in water flow and reducing floods or droughts.

The Paramos are called the "Water Towers" of the Andes because of their value for water supply

(WI, 2007).

Although the total species richness in peatlands in temperate climates is low, they al'e the

only available habitat for many endemic plant and animal species. Tropical peat swamp

forests represent, despite.,the lack of nutrients, a very high biodiversity ecosystem with thousands

of species, including many endemics, rare and endangered species. The black peat waters

support the highest density of freshwater biodiversity of the world (WI, 2007).

Malaysia's peat swamp forests not only comprise unique ecosystems that are home to

many endemic species but also provide sanctuary for viable populations of more than 60 animal

species listed as globally threatened including the Orang utan, Proboscis Monkey, Sumatran

12

Rhinoceros, Asian Elephant, Tiger, Civet Otter, Stonn's Stork and Wrinkled Hombill. Sebastian

(2002) provides an assessment of the current status of the mammal and bird fauna of both West

and East Malaysian peat swamp forest habitats where 57 mammal and 237 bird species recorded

in peat swamp forest, 51 % and 27% respectively are listed as globally threatened species (WI,

2007).

These moist forests also serve as a natural gene bank of potentially useful plant species as

well as providing highly valuable forest products such as high quality timber like ramin,

Gonystylus bancanlls and food. Many unknown species still remain to be discovered. Anderson

(1963) recorded 927 species of flowering plants and ferns in the peat swamp forests of Borneo. In

Peninsular Malaysia 260 species of plants were recorded from the Pekan Peat Swamp Forest

(Latiff,2005).

A total of 200-300 fish species are recorded from the peat swamps of Peninsular

Malaysia, Borneo and Sumatra (Dennis and Aldhous 2004) with 65 species recorded from Pekan,

and 47 from North Selangor Peat Swamp Forest (Ng et al., 1992, 1994). The Asian arowana

(Scleropages jormosus) which is a popular aquarium fish occurs in blackwater rivers in the

regional peat swamps. The world's smallest known fish (Paedocypris progenetica), <8 mm long,

was recently discovered· in the peat swamp forests of Sumatra (Kottelat et aI., 2006). The North

Selangor peat swamp forest is the most well studied area, from which 48 peat swamp fishes have

been recorded (Ng et al., 1992, 1994), include rare species, such as Encheloclarias, Bihunichthys,

Betla and Parosphromenus (Ng and Lim 1993; Ng and Kottelat, 1992, 1994). Far from being a

depauperate ecosystem, peat swamps possess an interesting fish fauna, which is diverse and

unique, and many of the species have narrow niches and restricted ranges.

13

d'

The reptile and amphibian fauna of regional peat swamp forests are not well known. A

survey of amphibians at Pekan revealed 19 species «30% of the species known from Malaysia)

ofwhich two are on the IUCN red list as 'near threatened' (Norhayati et al., 2005). Sharma et al.,

(2005) studied reptiles at Pekan and encountered 22 species, including four species of freshwater

turtles. The reptile and amphibian fauna of regional peat swamp forests are not well known. A

survey of amphibians at Pekan revealed 19 species «30% of the species known from Malaysia)

ofwhich two are on the IUCN red list as 'near threatened' (Norhayati et aI., 2005).

Coastal peat swamps act as a buffer between marine and freshwater systems, preventing

excessive saline intrusion into coastal land and groundwater. Intact peat swamps can contribute to

maintaining the water level in rivers that run through them during dry periods (UNDP, 2006). The

water from floods held in peat swamps is released gradually over a long period. By maintaining

base flows in rivers, peat swamps can prevent the intrusion of saline water up rivers and maintain

fresh groundwater in coastal areas. Intact peat swamp forests can diminish peak flood flows

mainly by reducing water velocity but also by providing a large area for storage of flood waters in

terms of spatial area and, to a very limited degree dependent on how waterlogged the peat is

already, through the water-holding capacity of the peat due to their flat topography and poor

drainage, during the wet season they store water above the forest floor (UNDP, 2006). When a

peat swamp area is flooded, the reduction in water velo~ity associated with it spreading over a

wide area, together with the retarding effects of vegetation, allows suspended sediments to settle.

Water flowing back into rivers will then be largely sediment free. Nutrients are often adsorbed

onto the surfaces of suspended particles and deposited along with them. These nutrients are likely

to be incorporated into biomass quite rapidly (UNDP, 2006).

14

Peat is very effective in binding metals. This largely accounts for the micronutrient

deficiencies (such as copper) that are encountered when using peat soils for agriculture. Other

metals (such as mercury and arsenic) are often bound in peat soils that are accumulated from

waterborne and airborne sources over long periods. Some such metals are toxic in large quantities

and peat acts as a reservoir for them (UNDP, 2006).

Numerous studies have suggested that peat deposits are well suited to the reconstruction

of both longer term and recent environmental changes. Thus, peat profiles can, for example,

provide records of the deposition of pollutants (e.g., Lee and Tallis 1979; Livett et aI., 1979;

Madsen 1981; Shotyk et aI., 1992; Jones and Hao 1993; Shotyk 2002). Recognition of this

function has gained importance in recent years due to the implication of raised C02 levels in

contributing to global warming. Tropical peat lands, besides acting as stores of carbon, actively

accumulate carbon in the form ofpeat. Because decomposition is incomplete, carbon is locked up

in organic form in complex substances formed by incomplete decomposition. Estimates suggest

that 5,800 tonnes ofcarbon per hectare can be stored in a 10-metre deep peat swamp compared to

300-500 tonnes per hectare for other types oftropical forest.

Peat swamp forest are used and managed for many different purposes. Undrained peat

swamp forests are valuable habitats for a wide range of biodiversity and ecosystem services and

many are managed as nature reserves. Drained peat swamp' forests are used mostly for agriculture

and forestry but also for peat extraction to provide energy, growing media and other products.

Peat swamp forests are also 'used' or managed indirectly as a result of other landscape activities,

for e~ample, urbanization, mining, recreation, reservoir construction, minerals extraction and

wind farms.

15

Effects of human activity in peat swamp forest

Of the original 27 million ha of peat forests in Southeast Asia, by 2006, 12 million ha

(45%) had been logged and almost as much had been drained (Hooijer et al. 2006). The drivers

that are leading to the loss of the peat forests are global market forces which demand especially

highly for oil-palm products, uses for food industry, and the growing demand for biofuels.

Regional peat swamp forests are primarily managed for timber production (Ng and Ibrahim

2001). In the past, prior to the introduction of mechanization, trees were selectively logged, and

only trees larger than. 45 cm dbh of high commercial value were taken (Ng and Ibrahim 2001).

Selective logging thus removes emergent trees, and when it is extensive it can reduce the canopy

height, reduce diversity (pioneer species colonize gaps) and decrease the stratification of forest

layers. Railway lines were constructed to remove logs by train, and then in the 1980s canal

systems, 3 m wide and 4 m deep, were developed" for log removal (Ng and Ibrahim, 2001). These

leave open scars that last for decades and are usually used in peat forests that are to be converted

to agriculture. Canals cause drainage alteration of the peat swamps hydrology and this adversely

impacts the peat substrate and vegetation, and makes them more susceptible to fires (Hooijer,

2006).

In addition, clearance ofthe peat swamp forest removes the source of freshly fallen leaves •. providing dissolves organic carbon, while burning, dramage and the application of lime and

fertilizers change the physicochemical conditions' further. When peat swamp forest are drained,

the aerobic conditions lead to breakdown and subsidence of the peat, and water holding capacity

is reduced to between 2 and 6 times their weight (Boeder, 1969), so the amount ofwater that can

be retained is far less than in the original peat forest and this will decrease the nutrients available

16