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.
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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
IIIMATERIAL 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
IVRESULT 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