EFFECTS OF PERMEABLE BARRIERS ON

TOTAL ECOSYSTEM CARBON STOCKS OF MANGROVE

FORESTS AND ABANDONED PONDS IN DEMAK REGENCY

TRIALAKSITA SARI PRISKA ARDHANI

APPLIED CLIMATOLOGY

GRADUATE SCHOOL

IPB UNIVERSITY

BOGOR

2020

DECLARATION

The author declares that this thesis entitled “Effects of Permeable Barriers

on Total Ecosystem Carbon Stocks of Mangrove Forests and Abandoned Ponds in

Demak Regency” was entirely completed by the author with the guidance of the

supervisory committee and has not been submitted in any form for another degree

or diploma to another tertiary institution of education. A part of this thesis has got

permission from IPB University to be submitted to a scientific journal as one of

the requirements to obtain a master’s degree. Information originating from the

existing publications has been duly credited and cited in the text and listed in the

reference section.

The author assigns the copyright of this thesis to IPB University.

Bogor, September 2020

Trialaksita Sari Priska Ardhani

Student ID G251170058

SUMMARY

TRIALAKSITA SARI PRISKA ARDHANI. Effects of Permeable Barriers on

Total Ecosystem Carbon Stocks of Mangrove Forests and Abandoned Ponds in

Demak Regency. Supervised by DANIEL MURDIYARSO and CECEP

KUSMANA.

Demak Regency experienced severe shoreline changes due to the massive

conversion of mangrove forests to aquaculture ponds. Therefore, Demak Regency

deals with coastal erosion by constructing permeable barriers that model

mangrove root structures. In this study, we observed the effects of these barriers in

the low- lying coastal zone of Demak Regency in the context of mangrove forest

structures and carbon (C) dynamics.

Forest structures were expressed by stand density, basal area, ecological

indices (richness, diversity, and evenness), species dominance, species

composition similarity, and species dispersion. The dynamics of C, performed as

total ecosystem carbon stocks (TECS), were assessed by estimating C pools from

above- and belowground biomass, dead organic matter, and soil. This study

established a stratified random sampling to capture mangrove forest structures and

TECS in mangrove forests, abandoned ponds, and productive ponds.

Avicennia marina occupied a generous portion of mangrove forests in

Demak Regency (IVI = 155.44). Our result revealed that tree density varied from

1378 ± 128 to 2244 ± 237 individuals ha−1, while basal area ranged between 9.29

± 1.33 and 13.56 ± 1.72 m2 ha−1. Statistically, mangrove forests with or without

the protection of permeable barriers varied in tree density but were not

significantly different in terms of basal area. This study also highlights that above-

and belowground C did not generously contribute to the variation of TECS.

Simultaneously, the low value of C in the form of necromass implied that a large

size of C in soil should be responsible for the tremendous variation of TECS.

This study discovered that duration of permeable barriers in coastal areas

affected the size of soil C captured in mangrove sites, i.e., 618.84 ± 30.39 Mg C

ha−1; 704.13 ± 17.73 Mg C ha−1; and 759.88 ± 15.26 Mg C ha−1 in 0-, 1-, and 4-

year-old permeable barriers, respectively. Critical analysis of TECS in mangrove

sites, abandoned ponds (610.82 ± 29.31 Mg C ha−1), and productive ponds

(735.57 ± 20.61 Mg C ha−1) suggested that introducing Avicennia sp. in newly

reclaimed coastline will enrich TECS. Furthermore, permeable barriers in

abandoned ponds have gradually served the habitat to grow for mangrove

seedlings, which were abundantly found in Sayung sub-regency. Therefore, this

condition is able to increase the stand density and thickness of mangrove stands,

which contribute to the maintenance of natural coastal stability in Demak

Regency.

Keywords: Avicennia marina, coastline, ecological indices, erosion, forest

structures.

RINGKASAN

TRIALAKSITA SARI PRISKA ARDHANI. Pengaruh Hambatan Permeabel

terhadap Total Stok Karbon Ekosistem di Hutan Mangrove dan Tambak

Terbengkalai di Kabupaten Demak. Dibimbing oleh DANIEL MURDIYARSO

dan CECEP KUSMANA.

Kabupaten Demak mengalami perubahan garis pantai yang parah akibat

konversi masal hutan mangrove menjadi tambak budidaya. Oleh karena itu,

Kabupaten Demak mengatasi masalah erosi pesisir dengan membangun

penghalang permeabel yang memodelkan struktur akar mangrove. Studi ini

mengamati pengaruh hambatan tersebut di zona pesisir dataran rendah Kabupaten

Demak dalam konteks struktur hutan mangrove dan dinamika karbon (C).

Struktur hutan ditunjukkan oleh kerapatan tegakan, luas bidang dasar,

indeks ekologi (kekayaan, keanekaragaman, dan kemerataan), dominasi spesies,

kesamaan komposisi spesies, dan penyebaran spesies. Dinamika C, yang

dinyatakan sebagai stok karbon ekosistem total (TECS), dinilai dengan

memperkirakan C pool dari biomassa di atas dan di bawah tanah, bahan organik

mati, dan tanah. Studi ini menetapkan pengambilan sampel secara acak bertingkat

untuk mengetahui struktur hutan mangrove dan TECS di hutan mangrove, tambak

terbengkali, dan tambak produktif.

Avicennia marina mendominasi sebagian besar hutan mangrove di

Kabupaten Demak (INP = 155.44). Hasil penelitian menunjukkan bahwa

kerapatan pohon bervariasi dari 1378 ± 128 hingga 2244 ± 237 individu ha−1,

sedangkan luas bidang dasar berkisar antara 9.29 ± 1.33 dan 13.56 ± 1.72 m2 ha−1.

Secara statistik, hutan mangrove dengan atau tanpa perlindungan penghalang

permeabel bervariasi pada kerapatan pohon tetapi tidak terlalu berbeda dalam hal

luas bidang dasar. Studi ini juga menyoroti bahwa karbon di atas dan dibawah

permukaan tanah tidak memberikan kontribusi yang besar terhadap variasi TECS.

Pada saat yang sama, nilai C yang rendah dalam bentuk nekromassa menyiratkan

bahwa ukuran C yang terkandung besar pada tanah bertanggung jawab atas variasi

yang besar pada TECS.

Penelitian ini menemukan bahwa durasi penghalang permeabel di wilayah

pesisir mempengaruhi ukuran C tanah yang ditangkap di lokasi mangrove, yaitu

618,84 ± 30,39 Mg C ha−1; 704,13 ± 17,73 Mg C ha−1; dan 759,88 ± 15,26 Mg C

ha−1 masing-masing pada penghalang permeabel berusia 0-, 1-, dan 4 tahun.

Analisis kritis TECS di lokasi mangrove, tambak terbengkalai (610,82 ± 29,31

Mg C ha−1), dan tambak produktif (735,57 ± 20,61 Mg C ha−1) menunjukkan

bahwa memperkenalkan Avicennia sp. di garis pantai yang baru direklamasi akan

memperkaya TECS. Selain itu, keberadaan penghalang permeabel pada tambak

terbengkalai secara bertahap dapat menyediakan habitat untuk tumbuh bagi bibit

mangrove yang ditemukan melimpah di Kecamatan Sayung. Dengan demikian,

kondisi tersebut mampu meningkatkan kerapatan dan ketebalan tegakan mangrove

yang berkontribusi pada terjaganya stabilitas alam pesisir di Kabupaten Demak.

Kata kunci: Avicennia marina, erosi, garis pantai, indeks ekologi, struktur hutan.

© Copyright IPB University, 2020

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It is prohibited to republish or reproduce all or part of this work, in any form,

without written permission from IPB University.

A thesis

as one of the requirements to obtain

Master of Science degree

in

Applied Climatology

EFFECTS OF PERMEABLE BARRIERS ON

TOTAL ECOSYSTEM CARBON STOCKS OF MANGROVE

FORESTS AND ABANDONED PONDS IN DEMAK REGENCY

APPLIED CLIMATOLOGY

GRADUATE SCHOOL

IPB UNIVERSITY

BOGOR

2020

TRIALAKSITA SARI PRISKA ARDHANI

Examiner team on a Master’s Defense: Dr. I Putu Santikayasa, M.Sc

Thesis title : Effects of Permeable Barriers on Total Ecosystem Carbon Stocks of

Mangrove Forests and Abandoned Ponds in Demak Regency

Name : Trialaksita Sari Priska Ardhani

Student ID : G251170058

Approved by

Supervisor:

Prof. Dr. Ir. Daniel Murdiyarso, MS __________________

Co-supervisor:

Prof. Dr. Ir. Cecep Kusmana, MS __________________

Acknowledged by

Head of Study Program:

Dr. Drs. Bambang Dwi Dasanto, M.Si _________________

NIP. 19650919 199203 1 002

Dean of Graduate School:

Prof. Dr. Ir. Anas Miftah Fauzi, M.Eng __________________

NIP. 19600419 198503 1 002

Examination date:

15 September 2020

Graduation date:

ACKNOWLEDGEMENTS

Praise and gratitude to God that has allowed the author to carry out the

study from 2018 to 2019 titled “Effects of Permeable Barriers on Total

Ecosystem Carbon Stocks of Mangrove Forests and Abandoned Ponds in

Demak Regency”. Besides, the author thanks her family, who always supports

her journey through their prayer and love.

On this occasion, the author also would like to express the deepest

gratitude to:

1. The supervisory committee headed by Prof. Dr. Ir Daniel Murdiyarso,

MS, and included Prof. Dr. Ir. Cecep Kusmana, MS. The author felt

grateful for their generosity in allowing the author to carry out this

study. To them, the author thanks for their guidance and various kinds

of support.

2. Yohanes Risky Shellen Ginting and Bayu Budi Hanggara. Both of them

kindly help in collecting the field data and giving precious advice in this

research. Also, I would like to thank local assistants, i.e., Kelompok

Study Ekosistem Mangrove Teluk Awur (KeSEMaT), Yayasan

Inspirasi Keluarga KeSEMaT (IKAMAT), and the coastal community

living in Betahwalang and Timbulsloko Villages. Especially, the author

and team would like to thank Mr. Nur and Mr. Slamet, who have been

so warm in welcoming the author’s team to settle at their house.

3. Ministry of Research, Technology, and Higher Education of the

Republic of Indonesia for providing the Pendidikan Magister menuju

Doktor untuk Sarjana Unggul (PMDSU) scholarship. The author also

acknowledges the grant provided by the United States Agency for

International Development (USAID) to the Center for International

Forestry Research (CIFOR) to operate the Sustainable Wetlands

Adaptation and Mitigation Program (SWAMP), by which this research

was organized.

During this study, many people help and support the author in several

ways. Individually, the author gives a sincere appreciation for their help, i.e.,

Iska Lestari, Turrisa Prigunanti, and every individual who contributed to this

work but not mentioned above. The author hopes this thesis will be

worthwhile for everyone, especially for future studies.

Bogor, September 2020

Trialaksita Sari Priska Ardhani

TABLE OF CONTENTS

LIST OF TABLES viii

LIST OF FIGURES viii

LIST OF APPENDICES ix

I INTRODUCTION 1

1.1 Background 1

1.2 Problem Formulation 2

1.3 Objective of the Study 2

1.4 Importance of the Study 2

1.5 Scope of the Study 3

II LITERATURE REVIEW 3

2.1 Permeable Barriers 3

2.2 Forest Structure 4

2.3 Carbon Storage 5

III MATERIAL AND METHOD 5 3.1 Study Site 5

3.2 Sampling Design 7

3.3 Assessment of Forest Structure 8

3.4 Estimation of Carbon Stock 11

3.5 Statistical Analysis 15

IV RESULT AND DISCUSSION 15 4.1 Result 15

4.2 Discussion 21

V CONCLUSION AND SUGGESTION 23

REFERENCES 24

APPENDICES 30

LIST OF TABLES

1 Rating ranges of richness, diversity, and evenness indices of

mangroves (Jorgensen et al. 2005; Hussain et al. 2012) 9 2 Allometric equation of tree and root in this study for estimating

vegetation biomass 11 3 Specific gravity (wood density) of the standard wood debris size

classes (Kauffman and Cole 2010; Kauffman and Donatto 2012) 13

4 Criteria for soil carbon concentration, nitrogen concentration, and

ratio of C:N (IAARD 2012) 15

5 Characteristics of forest structures in Demak Regency 15

6 Index of ecology, species dominance, similarity between mangrove

forests, and species dispersion in MF0 (mangrove forests without

protection), MF1 (mangrove forests protected by one-year-old

permeable barriers), and MF4 (mangrove forests protected by four-

year-old permeable barriers) 17

7 Soil properties of sampling sites in MF0 (mangrove forests without

protection), MF1 (mangrove forests protected by one-year-old

permeable barriers), MF4 (mangrove forests protected by four-

year-old permeable barriers), AP4 (abandoned ponds protected by

four-year-old permeable barriers), and PP0 (productive ponds) 18

8 Carbon pools (in Mg C ha-1) of each sampling sites in MF0

(mangrove forests without protection), MF1 (mangrove forests

protected by one-year-old permeable barriers), MF4 (mangrove

forests protected by four-year-old permeable barriers), AP4

(abandoned ponds protected by four-year-old permeable barriers),

and PP0 (productive ponds) 20

LIST OF FIGURES

1 Permeable barriers mimicking mangrove root systems (Winterwerp et al.

2014) 3

2 Construction of permeable barriers in a low-lying zone of Sayung sub-

Regency (Source: Kuswantoro/Wetlands International) 4

3 Study site in Wedung and Sayung sub-Regencies, Demak Regency,

Central Java Province (Source: Sentinel-2 earthexplorer.usgs.gov) 6

4 Circular plot layout for mangrove inventory (Kauffman and Donato

2012) 7

5 Line intersect method for assessing necromass carbon (Kauffman and

Donato 2012) 8

6 Measurement consideration of mangrove diameter (Pearson et al. 2005) 11

7 Decay status of standing dead trees (Kauffman and Donatto 2012) 12

8 Step for collecting soil samples using an open-face auger 14

9 Distribution of stand density based on tree diameter in MF0

(mangrove forests without protection), MF1 (mangrove forests

protected by one-year-old permeable barriers), MF4 (mangrove

forests protected by four-year-old permeable barriers) 16

10 Total ecosystem carbon stocks in MF0 (mangrove forests without

protection), MF1 (mangrove forests protected by one-year-old

permeable barriers), MF4 (mangrove forests protected by four-year-old

permeable barriers), AP4 (abandoned ponds protected by four-year-old

permeable barriers), and PP0 (productive ponds) 21

LIST OF APPENDICES

1 Forest structure among mangrove forests in Demak Regency 31

2 Distribution of stand diameter in MF0 (mangrove forests without

protection), MF1 (mangrove forests protected by one-year-old

permeable barriers), and MF4 (mangrove forests protected by four-

year-old permeable barriers) 32

3 Soil physicochemical properties in MF0 (mangrove forests without

protection), MF1 (mangrove forests protected by one-year-old

permeable barriers), MF4 (mangrove forests protected by four-year-

old permeable barriers), AP4 (abandoned ponds protected by four-

year-old permeable barriers), and PP0 (productive ponds) 33

4 Estimation of carbon (C) stocks (in Mg C ha-1) in all pools to estimate

total ecosystem C stocks in MF0 (mangrove forests without protection),

MF1 (mangrove forests protected by one-year-old permeable barriers),

MF4 (mangrove forests protected by four-year-old permeable barriers),

AP4 (abandoned ponds protected by four-year-old permeable barriers),

and PP0 (productive ponds) 34