Estimasi Biomassa dan Produktivitas Seresah Daun Mangrove untuk Pengelolaan di Pulau Enggano, Bengkulu, Sumatera, Indonesia

ESTIMATION OF BIOMASS AND LITTER LEAVES
PRODUCTIVITY OF MANGROVE FOR MANAGEMENT IN
ENGGANO ISLAND, BENGKULU, SUMATRA, INDONESIA

MOHAMMED SADEQ MOHAMMED AWN

GRADUATE SCHOOL
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2017

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DECLARATION OF ORIGINALITY
I hereby declare that this thesis titled “Estimation of Biomass and Litter
Leaves Productivity of Mangrove for Management in Enggano Island,
Bengkulu, Sumatra, Indonesia” and the work reported herein were composed
by and originated entirely from me under the supervision of my supervisory
committee. I therefore declare that; this is a true copy of my thesis as approved
by my supervisory committee and has not been submitted for a higher degree
to any other University or Institution. Information derived from the published

and unpublished work of others has been duly acknowledged in the text as
well as references given in the list of sources.
Bogor, March 2017

Mohammed Sadeq Mohammed Awn
Registration No.: C252148461

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RINGKASAN
MOHAMMED SADEQ MOHAMMED AWN. Estimasi Biomassa dan
Produktivitas Seresah Daun Mangrove untuk Pengelolaan di Pulau Enggano,
Bengkulu, Sumatera, Indonesia. Dibimbing oleh FREDINAN YULIANDA dan
YONVITNER.
Estimasi terhadap biomassa dan produktivitas seresah daun di hutan
mangrove memegang peranan sangat penting dalam siklus nutrisi dan potensinya
dalam menyerap karbon. Produktivitas mangrove sering ditentukan dengan ratarata seresah daun. Oleh karena itu, tujuan dari penelitian ini adalah untuk
mengidentifikasi spesies, menganalisa karakteristik dan memperkirakan biomassa
mangrove dan produktivitas seresah daun mangrove di Pulau Enggano.
Pengambilan data mangrove menggunakan metode transek kuadrat (10 m x 10 m)

secara acak dengan tujuh stasiun, dianalisa tegak lurus terhadap garis pantai. Enam
belas perangkap seresah daun dipasang di bawah pohon mangrove untuk
mengumpulkan seresah dari pohon-pohon dengan mengukur ukuran diameter
dengan tinggi dada (DBH) dan diameter lebih besar dari 4cm, hasil seresah daun
dibawa, diukur berat kering di laboratorium. Kepadatan relative mangrove jenis
Rhizophora apiculata, Bruguiera gymnorrhiza, Sonneratia alba, dan Xylocarpus
granatum, masing-masing adalah 63%, 27%, 6% dan 5%. Rhizophora apiculata
memiliki nilai tertinggi dan Xylocarpus granatum yang terendah. terdapat
hubungan linier antara biomassa dan tutupan batang mangrove dengan hasil
korelasi R2 = 0.95. Estimasi tutupan batang mangrove dan biomassa Bruguiera
gymnorrhiza memiliki nilai tertinggi adalah 95 m2/ha dan 139 ton/ha, sedangkan
yang terkecil adalah Xylocarpus granatum 13 m2/ha dan 21 ton/ha terendah. Ratarata diameter dan produktivitas masing-masing empat spesies adalah: Rhizophora
apiculata 28.8 cm, 2,6 g DW m-2 hari-1, Bruguiera gymnorrhiza 57 cm, 2,9 g DW
m-2 hari-1, Sonneratia alba 23.7 cm, 2,5 g DW m-2 hari-1, dan Xylocarpus granatum
38,3 cm, 2,7 g DW m-2 hari-1.
Peningkatan diameter tertinggi pohon mangrove memberi pengaruh
peningkatan produktivitas seresah daun pada setiap individu, spesies Bruguiera
gymnorrhiza menunjukkan produktifitas yang lebih tinggi dibandingkan dengan
spesies lain. Produktivitas berat kering serasah daun dihubungkan dengan diameter
batang (DBH) menunjukkan koefisien korelasi yang signifikan dan koefisien

korelasi dari semua spesies individu. Spesies Sonneratia alba adalah yang berkorelasi tertinggi dan yang paling rendah korelasinya adalah spesies Xylocarpus
granatum. Dari temuan itu, digambarkan bahwa ada dampak tak langsung dari
perubahan karakteristik hutan mangrove ditambah dengan perambahan manusia
yang menurunkan populasi Xylocarpus granatum dan Sonneratia alba, serta
rendahnya kepadatan semai dan anakan karena berkurangnya ukuran sedimen di
kawasan mangrove karena reklamasi lahan di pulau dan aktivitas pembangunan.
Karena itu diperlukan mitigasi lingkungan untuk melestarikan ekosistem. ini adalah
penelitian yang pertama memberikan informasi tentang biomassa dan produktivitas
daun sampah bakau di Pulau Enggano.
Kata kunci: Produktivitas, Mangrove, Vegetasi, Biomassa, Diameter Batang
Tegakan Pohon (DBH), Tutupan Batang Mangrove (stand BA).

SUMMARY
MOHAMMED SADEQ MOHAMMED AWN. Estimation of Biomass and
Litter Leaves Productivity of Mangrove for Management in Enggano Island,
Bengkulu, Sumatra, Indonesia. Supervised by FREDINAN YULIANDA and
YONVITNER.
Estimation of mangrove biomass and productivity litter leaves is an
important issue because it plays a vital role relevant to nutrient turnover and
potential carbon sink. Mangrove productivity is often determined by average litter

leaves. Therefore, the aim of this study was to identify species, characterization and
estimation of aboveground biomass and productivity litter leaves of mangrove
vegetation in Enggano Island, Sumatra, Indonesia. The data was collected randomly
at 10 m x10 m by quadrat transect sampling points along with seven stations laid
perpendicular to the shoreline. Sixteen litter traps were installed under the
mangrove trees individual to collect leave litter by recording the size diameter at
breast height (DBH) at random locations and was taken for dry weight in laboratory.
The relative density of species that were founded were Rhizophora apiculata,
Bruguiera gymnorrhiza, Sonneratia alba, and Xylocarpus granatum, 63%, 27%,
6% and 5% respectively. Rhizophora apiculata showed the maximum values and
Xylocarpus granatum showed the lowest. There was strong a correlation between
aboveground biomass and the stand basal area in mangrove which is explained by
R2 = 0.955. Estimation for the stand BA and biomass, Bruguiera gymnorrhiza
present the highest quantity at 95 m2/ha, 139 ton/ha and Xylocarpus granatum
showed the minimum values for stand BA and biomass 13 m2/ha, 21 ton/ha
respectively. The average DBH and productivity of dry weight litter leaves
individual for each specie, Rhizophora apiculata 28.75 cm and 2.6 g DW m-2 day1
, Bruguiera gymnorrhiza 57 cm and 2.9 g DW m-2 day-1, Sonneratia alba 23.75
cm and 2.5 g DW m-2 day-1, Xylocarpus granatum 38.3 cm and 2.7 g DW m-2 day1
respectively,

The analysis showed that increased the DBH of mangrove trees cause
increased in productivity of litter leaves in relation to significant correlation
coefficient. Bruguiera gymnorrhiza showed the highest productivity of dry weight
litter leaves as compared to the other species. The specie Sonneratia alba had the
highest value for correlation and the lowest correlation was shown by Xylocarpus
granatum. The findings illustrate there was indirect impact of change in character
of mangrove trees due to human encroachment evidence by the reduction in
Xylocarpus granatum and Sonneratia alba species population, as well the decrease
in density of both the seedlings and sapling because of the high sedimentation in
the mangrove areas due to land reclamation and acts of development. Therefore
urgent need for environmental mitigations to preserve the ecosystem. This is the
first result of research that could provide information about biomass and
productivity of mangrove litter leaves on Enggano Island.
Keywords: Productivity, Mangrove, Vegetation, Biomass, Diameter Breast Height
(DBH), Stand Basal Area (Stand BA).

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© Copyright, owned by IPB, 2017
All rights reserved

No part of this document may be reproduced or transmitted in any form or by
any means, electronic, mechanical, photocopying, recording, or otherwise, without
prior written permission from Bogor Agricultural University (IPB)
No part of this document may be reproduced or transmitted in any form without
prior written permission from Bogor Agricultural University (IPB)

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ESTIMATION OF BIOMASS AND LITTER LEAVES
PRODUCTIVITY OF MANGROVE FOR MANAGEMENT IN
ENGGANO ISLAND, BENGKULU, SUMATRA, INDONESIA

MOHAMMED SADEQ MOHAMMED AWN
A Thesis
Submitted in partial fulfillment of the requirements for the degree of
Master of Science
In
Coastal and Marine Resources Management

GRADUATE SCHOOL

BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2017

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External Examiner: Dr Ir Achmad Fahrudin, MSi

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ACKNOWLEDGEMENT
First and foremost I praise and acknowledge Allah, the most beneficent
and the most merciful. Secondly, my humblest gratitude to the Holy
Prophet Muhammad (Peace be upon him) whose way of life has been a
continuous guidance for me. I would like to express my deepest gratitude to
my advisors, Dr Ir Fredinan Yulianda and Dr Yonvitner as well as Dr Ir

Achmad Fahrudin as an external examiner whose invaluable supervisions,
guidance, support, enthusiasm and more importantly, constructive criticisms
have perfected and providing me with an excellent ambience for doing
research.
I also wish to acknowledge the Government of Indonesia through the
Ministry of Education and Culture (DIKTI) and KNB for the grant of
scholarship to pursue my master’s degree. I also wish to thank the all staff
Program study Coastal and Marine Resources Management, Department of
Living Aquatic Resources Management, Faculty of Fisheries and Marine
Science, Bogor Agricultural University (IPB) are much appreciated.
I further wish to thank all colleagues in the Bogor Agricultural
University (IPB), staff and colleagues in the university of Bengkulu, who
gave their contributions and help in diverse ways.
Furthermore, I would like to express my profound love and special
thanks to my loving parents; Mr. Sadeq Mohammed Awn and Mrs. Ulouf
Taha for their constant pieces of advice, guidance and prayers. Supports and
persistent encouragements from my siblings, especially to my brothers Mr.
Mr. Belal Sadeq and Mr Basam Sadeq and all friends during this study are as
well deeply appreciated.
Finally, I appreciate each and every person that directly and/or

indirectly contributed to the completion of this work piece. Indeed, you all
have played significant roles to this work and may Allah shower his bless
upon all of you.

Bogor, March 2017
Mohammed Sadeq Mohammed Awn

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TABLE OF CONTENTS
LIST OF TABLE

xiv

LIST OF FIGURE

xv

LIST OF APPENDICCES

xvi

1 INTRODUCTION
Background
Problem Statement
Research Objective
Significance of Research
Framework of Research

1
1
2
3
3
3

2 RESEARCH METHODOLOGY
Place and Time of Research
Research Materials and Tools
Method of Data Collection and Analysis

Character of Mangrove
Estimation Aboveground biomass of mangrove
Estimation of Productivity Litter Leaves of Mangrove
Environmental parameters

6
6
6
7
7
8
9
9

3 RESULTS AND DISCUSSION
10
Character of Mangrove Vegetation
10
Relative Frequency
10
Relative Density
11
Relative Dominance
12
Importance Value Index
13
Saplings
13
Seedling
14
Mangrove Condition in Enggano Island
15
Environmental Parameters
18
Estimation Aboveground Biomass and Stand Basal Area of Mangrove
Species
20
Correlation between Stand Basal Area and Aboveground Biomass of
Mangrove
22
Estimation Productivity Litter Leaves of Mangrove in Enggano Island
23
Correlation between Productivity Litter Leaves and Diameter Breast
Height of Mangrove in Enggano Island
25
4 CONCLUSION AND RECOMMENDATION
Conclusion
Recommendation
REFERENCES

27
27
28
30

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APPENDIX
BIOGRAPHY

35
30

LIST OF TABLES
1 Important value index of Mangrove species for all station in Enggano Island
2 Coverage area of classified Mangrove density year 2015 in Enggano Island
3 Estimation Aboveground Biomass (AGB, ton/ha) stand Basal Area (Stand
BA m2/ha) of Mangrove for all station in Enggano Island

13
17
22

LIST OF FIGURES
1 Framework of Research
2 Map of seven research stations in Enggano Island
3 Design nested plots observation Based Sampling
4 Procedure for measuring DBH for trees with unusual in different growth forms
5 Distribution of Mangrove for the seven station in Enggano Island
6 Relative Density of mangrove species for all station in Enggano Island
7 Relative dominance of Mangrove for seven stations in Enggano Island
8 Proportion sapling density of mangrove for all stations in Enggano Island
9 Proportion seedling density of Mangrove for seven stations in Enggano Island
10 Proportions of individuals density distribution of Mangrove for all station in
Enggano Island
11 Mangrove density mapping in Enggano island
12 Dendrogram showing of spatial clustering on 7 stations
13 Correlation of (Stand BA) and (AGB) of the mangrove species for all station in
Enggano Island
14 Average productivity litter leaves individual of Mangrove in Enggano
Island
15 Correlation between Productivity litter leaves and DBH of Mangrove species
individuals in Enggano Island
16 Zonation design of Mangrove in Enggano Island

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6
7
8
11
12
12
14
15
16
18
20
23
24
26
29

LIST OF APPENDIX
1
2
3
4

Relative Density of mangrove species for all station in Enggano island
Relative Dominance of mangrove species for all station in Enggano island
Relative sapling density of mangrove species for all station in Enggano island
Relative seedling density of mangrove species for all station in
Enggano island
5 Productivity litter leaves individual of mangrove species in Enggano island
6 Average productivity litter leaves individual of mangrove and diameter
breast height
7 Average of Stand BA, ABG of mangrove species for all station
in Enggano Island
8 Location Coordinates of Research
9 Environmental parameters
10 Field work images

36
36
36
36
37
37
37
38
38
38

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1 INTRODUCTION
Background
Mangrove is a coastal ecosystem found in tropical and subtropical
regions around the world, which are characterized by usually timbered
vegetation which is connected to other components of flora and fauna well
acclimatized to limiting conditions of salinity, uncombined substrate, little
oxygen and a habitat repeatedly submerged by the tides (Maia and Coutinho
2012). Generally Inhabiting in wet soils baggy of brackish to saline estuaries
and shorelines in the tropics and sub-tropics (Joshi and Ghose 2003).
As well as support for the environmental and marine system, especially
and the preservation of fish stocks and biodiversity as it provides food, a
shelter for species. As well as establishing an important source of organic
material to support marine system. This exported material, reinforced with
fungi and bacteria, produces the basis of the food web in the ecosystem (Maia
and Coutinho 2012). Globally, they are known to be generality the most
productive and unparalleled coastal ecosystems that support an extensive
range of goods and services and other marine systems (Aheto et al. 2011).
The above ground biomass (AGB) is the amount of standing organic material
per unit area at a given time, which is correlated to a position of productivity
system, an age of trees standing and organ allocation. The estimation of above
ground biomass provides increasingly valuable means for making
rapprochement among ecosystems and appraisement worldwide productivity
styles, provide knowledge is very important as a result of the evaluation study
of the technical aspects of forests such as primary productivity of mangroves,
nutrient cycling and energy flow. Consequently, biomass data are important
in order to comprehend forest ecosystem characteristics to establish the
appropriate management system based upon the sustainable yield principle
according to (Kusmana et al. 1992).
Mangrove trees are highly productive ecosystems with a healthy
diversity of flora and fauna in the intertidal regions of tropical and subtropical
coastlines. They have great ecological importance in shoreline stabilization,
alleviation of coastal erosion, sediment, and nutrient retention, storm
preservation, flow control, and water quality, besides their normal economic
benefit through diverse forest products. However, the situation with regarding
the mangrove has been retracted because of increased infringement for land
to be assigned to food and industrial production and settlements to meet
human needs and mangroves are important for their societal value, economic,
and ecological (Jachowski et al. 2013). Despite scientific consciousness of
the large carbon storage potential in mangrove biomass and soils, large areas
of mangrove in Southeast Asia have been lost in recent decades to civilization,
aquaculture, timber harvesting and anthropogenic activity ( Giri et al. 2008).
Mangroves along the Andaman coast for example, have declined an estimated
79% between 1961 and 1989, largely due to Human activities including
aquaculture (Saenger 2002), particularly following the 2004 Indian Ocean
Tsunami (Barbier 2006). A recent study in the Indo-Pacific region showed
that mangroves play a critical role in carbon imprisonment, potentially storing
four times as much carbon as other tropical forests, including rainforests

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(Donato et al. 2012). It has been estimated that the loss of the mangroves may
reach 60% by 2030 (Satyanarayana et al. 2011).
Enggano Island is one of the outer Islands of Indonesia, located in the
Indian Ocean, approximately 100 km South West of the mainland Sumatra
Island, it is separated from Sumatra Island by marine basin with a depth of
2 000 m. Biologically, it has high endemicity and a wealth of biodiversity.
Based on Enggano island expedition on 2015 there were many animal species
that were found (Astuti et al. 2016). Enggano Island as an area of small
islands has major potential in the form of the biological resources of coastal
and marine ecosystems such as mangroves, coral reefs, seagrass communities,
seaweed biological resources and biological resources fishery. The potential
of coastal and marine resources. The potential value of mangrove has been
well known. In addition to its function and the barrier against abrasion, a
windbreaker, and protector against tsunami, habitat for shrimp larvae and
fisheries, mangrove is also important as the provider of biological resources.
It produces wood, bioactive compounds etc. The natural condition of small
islands is good for such species that are adaptable to the sandy substrates and
low the input of organic sediments.
Enggano Island have varieties of ecosystems including mangrove
forests, coral reefs, seagrass, sandy coasts, which is main supporting people's
livelihoods has been exploited for a long time, and show the higher intensity
from time to time, that acceleration in the development of the island must be
based on the environment by taking into account capacity support of the
island Pressure on the resource potential of coastal and marine biodiversity in
the region Enggano future will be higher with the opening of accessibility to
Enggano island increasingly easy, according to the airport development plan
and roads now being implemented. Meanwhile, the government expects that
the potential of biological resources of small islands in Indonesia can be one
of the foundations of economic development in each region. according to
(Sobari et al. 2006), that the potential of natural resources and marine coastal
areas in Indonesia such huge need good management, so that utilization can
take place on an ongoing basis, in accordance with the concept of sustainable
development is the basis of the concept of national development. Enggano
island has an area of about 40 060 hectares. Around 14 377.35 hectares
(35.89%) is forest area, while the remaining 25 682 hectares (64.11%) is land
for other uses such as residential, agricultural land, and etc. The area of
mangrove forest ecosystems in Enggano is ± 1 414.78 ha (Nashsyah et al.
2011).
Problem Statement
Degradation of mangroves has far-reaching impacts including
threatening populations of fish and crustacean, and the other marine mammals
and birds that rely on mangroves. These impacts are compounded by a lack
of awareness about the importance of mangroves in the coastal and marine
environments, especially the relationship between mangroves and fisheries,
and also other supporting marine ecosystems such as the coral reef. Lack of
understanding of the value of mangrove trees and reviews their importance in
the ecosystem has led to a lot of problems. The leading cause of mangrove

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loss is conversion to shrimp and fish aquaculture in which coastal mangrove
forests are cleared for ponds, and land reclamation. Aquaculture pollutes local
water with effluents, they are destroyed by land-filling and cleared for the
construction of shrimp ponds. In coastal areas where human population is
increasing rapidly, mangroves are cutting for firewood and for construction.
Their productivity, and their reproductive capacity, as well as environmental
conditions, such as temperature and salinity, and other influencing factors are
near the upper limits for mangrove existence, which makes them very
sensitive to disturbance and can hinder their ability to recover. Mangroves
are prone to degradation and removal from a multitude of as well as industrial
activities developmental and exploitative activities. Maybe it’s because the
lack of knowledge of the ecological state of the mangrove and the collection
and preservation of data that serves the work of conservation and
management. It is necessary for study to determine the potential and the
existing condition of the mangrove ecosystem and provide recommendations
necessary policy directives in the sustainable management of mangrove
ecosystems.
Research Objectives
1. To identify the mangroves species located in Enggano island.
2. To analyse character of mangrove forest , relative density, relative
frequency, relative dominance, and importance value index.
3. To estimate the above ground biomass of the trees of mangrove and
relationship with basal (stand BA) and AGB for mangrove forest
communities in Enggano Island in relation to the mangrove tree species
composition.
4. To estimate productivity litter leaves of mangrove.
5. To determine the level of mangrove damage.
6. To make the recommendation for mangrove management and
conservation.
Significance of Research
1. Demonstrate the importance of mangroves for estimating the biomass and
productivity of mangrove trees to support ecosystem and maritime.
2. Can be used as the source of methodology approach for study evaluation
and as a source of information for other research for further investigation
to identify the determinants of degradation of mangrove forest.
3. To determine the status of mangrove damage rate and recommend the
mangrove ecosystem management strategies sustainable in coastal
Enggano Island.
4. The outcomes of the analysis to use in form of policy making as well as in
designing appropriate decision-making, and for assessing the effectiveness
of on-going policies and strategies for the reduction of loss of mangrove.
Framework of Research
Research methodology was designed to determine species and the characters
of existing mangroves to found the distribution, relative density and relative

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dominance, where that administration requirements based on adequate
knowledge about the mangroves to achieve protection and conservation to
ensure the survival of the ecosystem, because of its importance in the
environmental and maritime system support. The methodology also focused
on the risks which faced by the mangrove trees and verification of
environmental parameters in the study areas as temperature, dissolved
oxygen, pH, substrate, Salinity (Figure 1). The results analysis showed the
mangrove condition in Enggano Island and the possibilities that it offers to
support private marine environment, this study provides recommendations
that support the administrative work for the protection and conservation of
the mangrove trees.

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Mangrove Area

Mangrove Damage

Environmental
parameter

Ecology Mangrove

- Human Impact
-Natural Impact

-

Temperature
Dissolved oxygen
PH
substrate
Salinity

-

Identify
Distribution
Relative Density
Relative dominance

Biomass of
Mangrove

Litter Leaves
of Mangrove

Productivity
Mangrove character
Mangrove Condition

Mangrove potential Capacity

Mangrove Status

Recommendations and Future Perspectives

Figure 1 Framework of research

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2 RESEARCH METHODOLOGY
Place and Time of Research
The studies were conducted in Enggano Island, Sumatera, Indonesia.
To perform this research seven different stations in multiple regions east and
North West of island were selected, which were located at the coordinates S
05⁰: 25ʾ 43.0” to S 05⁰: 24 ʾ 10.0” and E 102⁰ 22ʾ 22.7” - E 102⁰ 23ʾ 19.5”
(Figure2). Enggano located in the zone of the Indian Ocean and
administratively included in North Bengkulu, Bengkulu Province, Sumatra,
Indonesia. Based on the decree of the President of the Republic of Indonesia
2005, according to rule number 78 the Enggano Island was included in the
list of small islands (Nashsyah et al. 2011). The study was conducted during
three months from November 2015 to January 2016.

Figure 2 Map of seven research stations in Enggano Island

Research Materials and Tools
Material and tools used for the study included; cameras, locations
documented using Global Positioning System (GPS), boats, roll meters, traps
mesh for litter leaves, plastic bag, stationery, raffia rope, Water Quality Meter
and ArcGIS 10.3 were used as a means of processing, interpretation of data
and guidebook classification of mangrove.

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Method of Data Collection and Analysis
Character of Mangrove
Mangrove species identification, in the work beginning in the field, it
has been classified as mangrove species which found within the study areas
by guidebook (Noor et al. 2006) and characters of mangrove ecosystems,
consisting of population density, relative density, importance value index,
frequency, relative frequency, dominance, relative dominance, and stand
basal area (English et al. 1994).The methods used in this study range from
ecological fieldwork to implementation, the quadrant transect method was
applied (English et al. 1994). The data was collected at 100 m2 quadrat at
random sampling points. Made seven stations laid perpendicular to the
shoreline (Figure 3). In order to cover all conditions of the research sites on
each transect, the random sampling points were taken using a 10 m×10 m
quadrat for each plot.

landward

Figure 3 Design nested plots observation based sampling; tree sample plot
10 x 10 m, saplings sample plots 5 x 5 m, seedling sample plots
1 x 1 m.
Plots were laid at seven stations to take samples. Plots were set up at
representative areas in mangrove forest, line transects were used from
seaward to landward (perpendicular to the coastline along the mangrove
forest zoning) in the intertidal area. In addition to made the plot size of 10 m
x 10 m for an adult tree, 1 x 1 m (English et al. 1994), the seedling and 5 x 5
m for the sapling (Bengen 2002) to assess the condition of mangrove, the
determination of vegetation of mangrove for each specie was counted the
number of individuals and density of each type and size of each circle
mangrove trunk at breast height about 1.3 m for the trees mangrove adult
diameter > 4 cm (Figure 4). The method used was single plot random
repetition, where the technique to make sub-plot followed the growth stage
(English et al. 1994).
Variables observed, calculated, and analyzed in the study were: (1)
Identification of mangrove species used by the guidebook (Nor et al. 2006),
(2) Character of mangrove ecosystems, the data gathered was analyzed using
the parameters: population density, relative density, importance value index,
frequency, relative frequency, dominance, relative dominance and basal area.

8

Relative density =
Frequency =

Relative frequency =

Dominance =

Relative dominance =

.

.

x

I W

�

.

.
y

y

X

I

X

.

.

.

Importance value index (IVI) = relative density + relative frequency + relative
dominance.
Basal area = µ DBH2/4 (English et al. 1994).

Figure 4 Procedure for measuring DBH for trees with unusual in different
Growth forms (English et al 1997)
Estimation Aboveground Biomass of Mangrove
Aboveground biomass was determined by the summing of the
biomass of stem. The total aboveground biomass for mangrove species was
calculated from the summation of tree biomass found from sampling plot. The
data for biomass and stem volume was converted into hectares and used
allometric equations was the most common and widely used method for
measuring biomass. The equations were derived from selective sampling of

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mangrove trees that are representative of the size-classes in the forest to
estimate the partial weight of trees relative to tree metrics, such as diameter
breast height (DBH) and tree height (Suzuki and Tagawa 1983).
� = � ∗ ��� ∗ � � , were Y = biomass value is a dependent
variable, DBH = Trunk Diameter (diameter at breast height). Where a and b
are regression constant = (Rhizhophora = 0,101; Bruguiera = 0.150; and
others = 0.145), H = Height of tree, a = coefficient (Rhizhophora = 0.931;
Bruguiera = 0.784 and others = 0.827) D = Density (ind/ha), (Suzuki and
Tagawa 1983).
Estimation of Productivity Litter Leaves of Mangrove
Litter traps were constructed taking into consideration the mesh size
(Brown, 1984). The litter trap must not retain moist but must be dry as any
presence of moisture will enhance the process of decomposition which may
reduce the weight of the litter (Mohit and Appadoo 2009). The trap was made
from nylon fabric a mesh size of 1 mm × 1 mm of the trap was suitable enough
to prevent any loss of litter materials caused by the constant bouncing out of
the litter traps to the mangrove trees as a result of strong winds. The litter
traps had a Square frame of one meter which made up of raffia rope. Square
frames of raffia ropes were constructed to facilitate the handling of the litter
baskets and also for them to be easily fitted among the mangrove trees. Traps
were placed in different stations. Each litter trap was attached tightly to the
trunk of the mangrove trees above the high-tide more than mark 0.5 m (Cunha
et al. 2006). The litter traps were emptied during the two-week period starting
at the first December 2015, the litter leaves were collected in plastic bags
from sixteen traps of different stations and were taken to the laboratory, were
dried at 70°C for 3 days and then calculate and analyze weights According to
the following equations:
Dry Weight of litter g DW
= g DW m−
Area Traps m

The dry weight of litter (g DW) for each litter trap is calculated in a surface
area of 1 m2.
Dry Weight of litter g DW m−
= g DW m− day −
Number of Days Between Each Collection Date

The rate of litter fall is then calculated by dividing the dry weight of
litter (g DW m− ) by the number of days between each collection date (Abib
and Appadoo 2012).
Environmental Parameters

Water samples taken from mangrove ecosystem, which is located near
the mangrove in transect quadrat. Water samples were measured by water
quality checker for pH, salinity, dissolved oxygen, temperature. All these
statistical analyses were performed using Agglomerative Hierarchical
Clustering (AHC) statistical, Cluster analysis indicates that the mangrove

10

forests sampled, and to find out similarities in all samples stations for analysis
of the environmental situation. Sediment samples at each mangrove site were
determined for substrate (sand, silt, and mud) to identify the type of substrates
in the mangrove areas in transect quadrats.

3 RESULTS AND DISCUSSION
Character of Mangrove Vegetation
The characterization of the plant structures of mangrove was based on the
methodology proposed by (English et al. 1994), which recommended that the
use of multiple squares, the replication of samples in order to be more
representative and to allow for more robust statistical analysis. In each
location, seven station were chosen and each area was marked by transects of
3 quadrats measuring 100 m2 for each plot. An observation of the
characteristics of mangrove vegetation in this study concerned on the seven
observations of differnt locations as the focus for the relative frequency,
importance value index, estimate the above ground biomass and their
relationship with a basal area of the mangrove trees and identification of the
species within the study areas. Frequency is the number of sampling units in
percent in which a particular specie occurs as the probability of finding the
any specie in plot and only be compared between plots of equal size,
importance value index, estimate the above ground biomass and their
relationship with a basal area of the mangrove trees and identification of the
species within the study areas (English et al. 1994).
Relative Frequency
The frequency is the number of plots on which species occurs divided
by the total number of plots sampled. Frequency data was used to detect
changes in plant abundance and distribution on a range site over time or to
identify differences in species responses to varying management practices.
Selection of the proper plot size is extremely important for estimation of
frequency, and more than one plot size may be needed for varying plant
species and plant distribution. Frequency data was easily obtained, but
numerous sample plots must often be evaluated before reliable estimation can
be derived. Most species in mixed mangrove forest give frequency above
0.05. This indicates that all plot samples have mangrove species. Most of the
plots were dominate with Rhizophora apiculata because this species showed
the highest total of frequency 0.85. Rhizophora apiculata indicated the
highest total of the important values compared to the other three mangrove
species which was derived from the total relative density, relative dominance
and relative frequency. If the species showed a higher important value
indicated that species was in abundance and can be founded diversely in the
study areas as pioneer species (kasawani et al. 2007).
Analysis data was given to seven stations at different locations there
was founded four species and were identified. The highest value relative
frequency for mangrove types in stations, Proportions of individuals
distribution of mangrove species are follows: Rhizophora apiculata 75% in

11

station 1, Bruguiera gymnorrhiza 43% in station 2, Sonneratia alba 50% in
station 6 and Xylocarpus granatum 33.3% in station 3 and It was observed
that the relative values of Rhizophora apiculata type was the highest in all
stations (Figure 5).

Figure 5 Distribution of mangrove for the seven station in Enggano Island
Relative Density
The highest existed density was for Rhizophora apiculata trees
because it has high ability of adaptation in different environmental conditions.
This specie was founded in the intermediate estuarine zone in the midintertidal region. This specie tolerates a maximum salinity of 65 ppt and a
salinity of optimal growth of 8 to 15 ppt (Robertson and Alongi 1992). It is
hard and fast-growing specie. This specie can grow upto 30 m. Based on the
performed observation and analysis of mangrove ecosystem in the seven
stations (Figure 6), relative density was calculated by percentage founded in
every observed mangrove vegetation the highest percentage of the species
density from all stations (1) Rhizophora apiculata 95 %, (2) Bruguiera
gymnorrhiza 57 %, (3) Sonneratia alba 29 %, and (4) Xylocarpus granatum
17 % Figure 6. Relative density analysis shows that the Rhizophora apiculata
is the most dominant mangrove specie in all study stations. The notable
volume of Rhizophora apiculata shows that it is the most adapted species in
Enggano Island. The fruit of Rhizophora apiculata has good adaptations in
terms of dispersal and establishment. It can almost grow and thrive on its own.
Therefore, Rhizophora apiculata can be considered as the best option in the
efforts of mangrove reforestation.

12

100
80
60

% 40
20
0

Station 1 station 2 Station 3 Station 4 Station 5 Station 6 Station 7

Rhizophora apiculata
Xylocarpus granatum

Bruguiera gymnorrhiza
Sonneratia alba

Figure 6 Relative density of Mangrove for all station in Enggano Island
Relative Dominance
Analysis of relative dominance of mangrove vegetation in the
observed seven station found that: (1) Rhizophora apiculata value of 98% in
station one, (2) Bruguiera gymnorrhiza has the value of 91%, (3) Sonneratia
alba has a value of 35%, and (4) Xylocarpus granatum has value 22%. This
relative dominance analysis of mangrove vegetation in the seven observed
locations showed that (Figure 7) Rhizophora apiculata has the highest relative
100

%

80
60
40
20
0

ST1

ST2

ST3

ST4

ST5

ST6

ST7

Relative Dominance

Rhizophora apiculata
Xylocarpus granatum

Bruguiera gymnorrhiza
Sonneratia alba

Figure 7 Relative dominance of Mangrove for seven stations in Enggano
Island
dominance value compared to the other species at the place which was
protected from the waves, mangrove communities especially excelled by
mangrove Rhizophora apiculata and conditions of mangrove forests that deal
directly with the sea, so as to get the tide is very supportive of that type to
grow. Presumably, Rhizophora apiculata has the ability to adapt and cope
with larger environmental conditions as compared to other species in high
salinity or the level different especially in estuaries (Sambu et al. 2014).
Which explained its wide adaptability in different areas. The mangrove trees
studied in Enggano Island were founded to be dominated by Rhizophora

13

apiculata, presenting reduced structural development and low density for
Sonneratia alba and Xylocarpus granatum.
Presumably, Rhizophora apiculata has the ability to adapt and cope
with larger environmental conditions as compared to other species in high
salinity or the different levels especially in estuaries (Sambu et al. 2014).
Importance Value Index
Importance value index of mangrove vegetation ranges from 0 to 300
(Sambu et al. 2014). This IVI will become an overview about the influence
or role of a plant in the community within vegetation ecosystem. To find out
the IVI was calculated and analyzed for both relative density, relative
dominance, relative frequency, analysis of IVI of mangrove vegetation details
refers (Table 1), (1) Rhizophora apiculata reaches 267.57 highest importance
value index in the first Station and lowest was in station five. (2) Bruguiera
gymnorrhiza 181 highest IVI value in station five and showed the less
valuable in station seven are value 74 in terms of dominance. (3) Xylocarpus
granatum the highest IVI value was 73 in station three, Lowest IVI value 22.
(4) Sonneratia alba 89 station seven and lowest was 22 in station five. The
Zero values in some stations is non-existence for a type. The findings showed
that specie Rhizophora apiculata has the most dominant influence in the four
type’s mangrove ecosystems. Based on the observed and analysis of
importance value index of mangrove vegetation, the composition of
vegetation in the observed seven locations has heterogeneous, as it is shown
by the observation and analysis of the four-species mentioned, but it has lowlevel heterogeneity. In fact, one of the indicators that mangrove ecosystem is
healthy when it has high heterogeneity or when the ecosystem has high
biodiversity.
Table 1 Important value index of Mangrove species for all station in
Enggano Island
Importance Value Index
Species
St1
St2
St3
St4 St5 St6
Rhizophora apiculata
267.6
127
101 212 74 220
Bruguiera gymnorrhiza
Xylocarpus granatum
Sonneratia alba

St7
178

0

151

126

88

181

0

33

32.4

22

73

0

23

0

0

0

0

0

0

22

80

89

Saplings
Sapling category was founded in the study sites includes three species
Rhizophora apiculata, Bruguiera gymnorrhiza and Xylocarpus granatum.
The species Rhizophora apiculata was founded in all stations with the highest
value in most station and with percentage of 100 in stations 1, 6 and 7. The
lowest value of density percentage of sapling was at station 3 with the value
of 54%, where the density of sapling concentrated in the nearby plot of the
sea within the water line, which has simple slope an extension in coast,

14

followed the higher values of Bruguiera gymnorrhiza in station 3 a
percentage of 42%, and the lowest value of saplings density of the specie
Xylocarpus granatum at station 3 by a percentage of 4% (Figure 8). Specie
Bruguiera gymnorrhiza existed in shallow mud substrate where flowing
rivers, as has been found the specie Rhizophora apiculata in all environmental
conditions of the study sites because the Rhizophora have roots ability to
installation in different types of substrate. Annual sedimentation rates in
mangrove forests often associated with the expansion of land seaward.
Channels, however, are more susceptible to human induced sedimentation
rate variability. Seedling growth was affected differently by sediment burial
in the different species (Thampanya et al. 2002).
100
80
60
% 40

20
0
Station 1 station 2 Station 3 Station 4 Station 5 Station 6 Station 7

Rhizophora apiculata
Xylocarpus granatum

Bruguiera gymnorrhiza
Sonneratia alba

Figure 8 Proportion sapling density of Mangrove for seven stations
in Enggano Island
Seedling
Shown in (Figure 9) the seedling of specie Rhizophora apiculata was
dominant in all study stations which has occupied the highest percentage,
where the maximum seedling was at station 6 and 7 with the value of 100%,
because the high density of specie Rhizophora apiculata in these stations and
it owns edged fruit ability to install in the soil after the fruit falling season
which cause new germination. Bruguiera gymnorrhiza has the second highest
value, and the highest value of Bruguiera gymnorrhiza was at station 2 with
the value of 43% (Figure 9). While Xylocarpus granatum was present in the
first and third station where it has lowest density values among all the species
at different study stations.
According to (Saheb et al. 2015) the specie Xylocarpus granatum was
highly sensitive to high water level and very low water levels, especially at
early development stage, the favorable water levels range for seed
germination at 3 cm to 2 cm from the soil. Example in the position of seed,
radical should be connected with soil. Wilted nature of primary roots, position
of seeds in the soil may be a difficult situation for establishment of Xylocarpus
granatum. Photosynthetic performance of plants reflects seed germination
pattern. Thus, artificial breeding and culture should be adopted to ensure a
higher survival rate of Xylocarpus granatum seedlings. Due to these
difficulties, seedling establishment at botanical garden of ANU took up 3 to
4 months. The above studies are a step towards understanding the

15

distributional and propagation difficulties of an important mangrove plants.
As well the mangroves seedling occur in tropical habitats where they are
exposed to high light intensities. The intense light can damage the mangrove
seeds and drop the photosynthetic rate (Cheeseman 1994). Rhizophora
seedlings were not significantly affected by the burial levels. Seedling
impaired if they are covered by sediment, tropical rivers carry massive
amounts of sediments during the rainy season (Milliman and Meade 1983)
which are discharged into coastal waters, frequently as sudden highsedimentation events. Such events can cause extensive burial of the mangrove
aerial roots, inhibit root aeration, and consequently, lead to widespread
mortality (Ellison 1999).
100
80
60
% 40
20
0
Station 1 station 2 Station 3 Station 4 Station 5 Station 6 Station 7

Rhizophora apiculata
Xylocarpus granatum

Bruguiera gymnorrhiza
Sonneratia alba

Figure 9 Proportion seedling density of Mangrove for seven stations
in Enggano Island
Mangrove Condition in Enggano Island
The mangrove system is very dynamic, where changes take place
regularly, and within the range of mangrove habitats, most major species
grow within a given set of conditions. Mangroves are salt-tolerant forest
ecosystems of tropical and subtropical intertidal regions. They occur in
sheltered coastline areas such as small bays, estuaries, lagoons, creeks and
sea channels separating islands and certain locations where the soil conditions
are favorable such as mud flats and swamps. Mangroves are highly productive
intertidal ecosystems in tropical and subtropical regions. Despite the
established importance of mangroves to the coastal environment (Chellamani
et al. 2014), But the mangroves are among the most degraded ecosystems in
the World (Peter 2013). Degradation of this system continues mainly due to
anthropogenic pressure (Chellamani et al. 2014). Human activities and
natural disaster may bring affect for mangrove existing and its density. Solid
waste and sediment as in some stations 5, 6 in the study area is one of
problems leading to the decrease of mangrove forest area in kaya apo village.
In order to assess mangrove distribution, the mangrove density changes
should be monitored through mapping.
In this research, mangrove density was divided into 3 classes build
upon histogram of NDVI transform which adjusted in Landsat images.
Mangrove density classes were divided as sparse, moderate and dense based

16

on NDVI range in images. The coverage area of mangrove density classes is
shown by (Table 2). Types of mangrove dominated in Enggano Island were
Rhizopora apiculata, Bruguiera gymnorrhiza, Sonneratia alba, and
Xylocarpus granatum. Image processing from Landsat 8 divided mangrove
density into 3 classes based on NDVI range from Ministry of Forestry
therefore, the mangrove ecosystem could be visually observed in good status
(based on Decree of the Minister of Environment No.201/2004 – Criteria and
Guidelines for Determining Mangrove Damage). Density classes are spares
(NDVI range: -1 to 0.33; equal with < 1 000 Trees/Ha), moderate (NDVI
range: 0.33 to 0.42; equal with ≥ 1 000 to < 1 500 Trees/Ha), and dense
(NDVI range: 0.42 to 1; equal with ≥ 1 500 Trees/Ha).
Dense Vegetation: Dense mangrove shows good health status of
mangroves which indicates tall trees, fine distribution, diversity extent and
excellent local habitat for the mangrove growth. Mangrove covers the area
of about 661.2 ha area coverage 55.5% (was taken as dense mangrove
vegetation. Mangrove in Enggano island are dominated by Rhizopora
apiculata, Bruguiera gymnorrhiza, Sonneratia alba, Xylocarpus granatum.
Overall, in this study mangrove community in Enggano island has good
density for Rhizopora apiculata 63%, Bruguiera gymnorrhiza 27%. It was
shown by dense mangrove coverage area.
Relative density of the mangrove species in all stations based on the
identification and analysis, mangrove ecosystem for each species found is
given as (1) Rhizopora apiculata 63%, (2) Bruguiera gymnorrhiza 27% (3)
Sonneratia alba 6%, and (4) Xylocarpus granatum 5%. Relative density
analysis shows (Figure 10). Shows that Rhizopora apiculata was the most
dominant specie. Presumably, it has not only vastly zonation but also have
fast growth rate compared to other vegetation types.
Moderate Vegetation: The canopy covers the area of about 467.3 ha with
percentage 39.2% which is taken as moderate vegetation of mangrove forest,
the dominant variety in the entire mangrove forest of the Enggano Island.
5%

6%

27%
63%

Rhizophora apiculata

Bruguiera gymnorrhiza

Xylocarpus granatum

Sonneratia alba

Figure 10 Proportion of individual’s density distribution of Mangrove
for all station in Enggano Island
It highlights the moderate health of the forest. It will probably be species
Sonneratia alba, with moderate density , as evidenced by the results of the

17

analysis in the field study stations that showed the presence of a weak density
6% and lack of presence in some stations, but was seen have more density
out side the stations.
Degraded Vegetation: The degraded forest denotes the loss of canopy
cover, lower-stand density and degrading forest habitat due to changes in
environmental conditions and natural factors such as storms in around
mangrove (Kuenzer et al. 2011). The canopy cover indicates the mangroves
condition. Both the salt tolerant and riverine mangroves was present in this
vegetation type and cover around 62.3 ha with percentage 5.2% (Table 2), in
the areas of Enggano Island, which shows the maximum percentage of
degradation of mangroves in study stations where Xylocarpus granatum
presence was about 5% (Figure 6). Which represents the lowest percentage
of species of mangrove located within the field study. The factors affecting
the mangrove environment in Enggano Island were sediment, due of the land
reclamation and development work. Sediments are material of varying size of
mineral and organic origin. The process of deposition of sediment from a state
of suspension or solution in a fluid is called sedimentation.
Table 2 Coverage area of classified Mangrove density year 2015 in
Enggano Island
Classes of density

Coverage area (Hectares)

Percentage (%)

High

661.2

55.5

Moderate

467.3

39.2

Rarely

62.3

5.2

Total

1 190.8

100

Natural sources of sediments transported to the sea include erosion of
bedrock, soil and decomposition of plants and animals (GEMS and
Programmes 2006). Natural sediment mobilization is an important process in
the development and maintenance of coastal habitats, including mangroves,
dunes and sand barriers. However, anthropogenic activities or those which
are carried out by man, often change the processes of erosion and
sedimentation as well as modifying the flow of rivers and the amount of
sediments that it can carry. The effects of changes to sedimentation patterns
depend on whether the change results in an increase or decrease in sediment
availability. Both effects have various physical and chemical consequences
for water quality and aquatic ecosystem health. Increased sedimentation in
the study area through the Rivers has smoothen marine communities and in
severe cases it will burial leading to suffocation of corals, mangrove stands
and sea grass beds. It has also caused intrusion of many toxic organic
chemicals, heavy metals and nutrients which were physically and/or
chemically absorbed by sediments (Peter 2013).

18

Figure 11 Mangrove density mapping in Enggano Island
Envi