Prototype-Scale Physical Model of Wave Attenuation Through a Mangrove Forest of Moderate Cross-Shore Thickness: LiDAR-Based Characterization and Reynolds Scaling for Engineering With Nature

This study investigates the potential of a Rhizophora mangrove forest of moderate cross-shore thickness to attenuate wave heights using an idealized prototype-scale physical model constructed in a 104 m long wave flume. An 18 m long cross-shore transect of an idealized red mangrove forest based on the trunk-prop root system was constructed in the flume. Two cases with forest densities of 0.75 and 0.375 stems/m2 and a third baseline case with no mangroves were considered. LiDAR was used to quantify the projected area per unit height and to estimate the effective diameter of the system. The methodology was accurate to within 2% of the known stem diameters and 10% of the known prop root diameters. Random and regular wave conditions seaward, throughout, and inland of the forest were measured to determine wave height decay rates and drag coefficients for relative water depths ranging 0.36 to 1.44. Wave height decay rates ranged 0.008–0.021 m–1 for the high-density cases and 0.004–0.010 m–1 for the low-density cases and were found to be a function of water depth. Doubling the forest density increased the decay rate by a factor two, consistent with previous studies for other types of emergent vegetation. Drag coefficients ranged 0.4–3.8, and were found to be dependent on the Reynolds number. Uncertainty in the estimates of the drag coefficient due to the measured projected area and measured wave attenuation was quantified and found to have average combined standard deviations of 0.58 and 0.56 for random and regular waves, respectively. Two previous reduced-scale studies of wave attenuation by mangroves compared well with the present study when their Reynolds numbers were re-scaled by λ3/2 where λ is the prototype-to-model geometric scale ratio. Using the combined data sets, an equation is proposed to estimate the drag coefficient for a Rhizophora mangrove forest: CD = 0.6 + 3e04/ReDBH with an uncertainty of 0.69 over the range 5e03 < ReDBH < 1.9e05, where ReDBH is based on the tree diameter at breast height. These results may improve engineering guidance for the use of mangroves and other emergent vegetation in coastal wave attenuation.

Entrepreneurship Workshop in Kampung Nelayan’s Community, Medan Belawan District

Approximately 600 families inhabit the Kampung Nelayan of Medan Belawan District; most of them work as fishermen. The people of Kampung Nelayan have limited facilities and relatively low knowledge of entrepreneurship which caused an inability to maximize the potential of marine natural resources and mangrove forest resources. Entrepreneurship workshop activities are carried out to equip the public to have a good knowledge of entrepreneurship, which is expected to generate and increase the spirit of entrepreneurship in utilizing and managing the potential of natural resources into high selling value products. The activities were carried out using a quasi-experimental one-group pretest-posttest approach. The results of the pretest and post-test were used to measure changes in participants knowledge. The results of the outreach activities showed that there was a change in participants entrepreneurial knowledge, marked by an increase in the average number of pretest and post-test scores. However, in terms of the number of individual scores, there were variations in participants' knowledge, namely increasing, constant, and decreasing. Following up on this result, it is necessary to conduct entrepreneurship assistance and workshops to implement knowledge in managing businesses and marketing them to improve the economy.

Assessment cytotoxic assay of Rhizophora plants mangrove using brine shrimp (Artemia salina L) model

Rhizophoraceae is the main family of mangroves as a source of bioactive compounds originating from the coast. Ethnophamacologically Rhizophoraceae has been used in various traditional medicine. Natural sources as anticancer from the Rhizophoraceae family are interesting to know. This study aimed to determine the cytotoxic bioactivity of methanolic extracts of roots, bark, leaves, and fruit/hypocotyl from five species of Rhizophoraceae (Bruguieria cylindrica, B. gymnorrhiza, Ceriops decandra, Rhizophora apiculata, and R. mucronata) from the Langsa mangrove forest, Aceh. The method used in this study was the Brine Shrimp Lethality Test (BSLT) bioassay using Artemia salina Leach at extract concentrations of 1, 10, 100, 500, and 1000 μg/ml. Samples were extracted using the maceration method and methanol as the solvent. The cytotoxic activity of 20 Rhizophoraceae methanol extracts showed that 12 extracts were toxic with an LC50 range of 31.5 - 934.9 μg/ml (based on LC50 ≤ 1000 μg/ml). The two extracts of which the closest to highly toxic (based on LC50 ≤ 30 μg/ml) were C. decandra bark showed LC50 of 31.5 μg/ml, and R. mucronata bark showed LC50 31.8 μg/ml. This shows that Rhizophoraceae extract has potential as a natural anticancer agent. In the five rhizophoraceae species, C. decandra was the most active compared to other species. In the four plant parts, the bark was the most toxic.

Impacts of Livelihood Activities on the Environment and Natural Resources of Can Gio Mangrove Forest, Ho Chi Minh City

In recent years, local livelihood activities in the Can Gio district have increased significantly, including aquaculture practices, aquaculture cultivation, salt-works, forest guard, farming, livestock, tourism, and etc. These livelihood activities have contributed remarkably to the local economy and the improvement of living conditions for local people. However, the burgeoning development of these activities have posed negative impacts on the mangrove ecosystem in Can Gio. In which, the use and exploitation of existing human and natural resources are paid inadequate attention. The purpose of this study is to identify livelihoods by conducting a survey with 536 questionnaire samples in both the buffer and transition zones in Can Gio Mangrove Forest. In addition, the quality of surface water sources was examined by collecting 70 surface water and wastewater samples. The results show that the quality of surface water meets the allowable limits of QCVN 08-MT:2015/BTNMT. The extent of the impact from livelihood activities on the environment of mangrove forest is at the medium level. However, the livelihood of aquaculture cultivation practices has the most affect on the environment and natural resources and is posing negative impacts on the quality of water sources in Can Gio Mangrove Forest. Therefore, these findings will be useful information for decision makers of the local authority in building an appropriate planning for aquaculture cultivation area. Further, irrigation and drainage systems for aquaculture practices need to be invested to control and handle wastes from aquaculture cultivation areas.

Edukasi Eksistensi dan Keberlanjutan Ekosistem Hutan Mangrove untuk Remaja

Indonesia has 3.4 million hectares or 24% of the world's 13.8 million hectares of mangrove forests. In its development, Indonesia's mangrove area continues to decline and it is recorded that an area of ​​637,624 hectares (18.95%) is in critical condition due to canopy cover which is less than 60%. Mangrove forests can absorb large waves including tsunamis, prevent abrasion, absorb carbon dioxide 5 times greater than tropical forests in the highlands, and are a habitat for several types of wildlife. Thus, Indonesia has a very significant role in the existence and sustainability of the world's mangrove forests. Based on 2018 data, DKI Jakarta Province has 300 hectares or about 10.7% of the total mangrove forest in Indonesia which is spread in the Angke Kapuk Nature Park, Muara Angke Wildlife Sanctuary, Angke Kapuk Protection Forest and Kamal Muara Production Forest as well as part of the last remaining mangrove forest in DKI Jakarta province. Based on this phenomenon, efforts are needed to maintain the existence and sustainability of mangrove forests, especially in the city of Jakarta. One of the important actors in this effort is the youth with growing awareness of environmental issues. Teenagers as future milestone holders need to understand the importance of the existence and sustainability of mangrove forests. The problem faced is the need for an educational activity that is by the characteristics of adolescents. Therefore, the implementing team initiated education on the existence and sustainability of the mangrove forest ecosystem for youth (12-24 years old) in Tanjung Gedong Village who are members of the At-Taufiq Tanjung Gedong Mosque Youth with an Experiential Learning Discovery Journey approach which was carried out in 3 (three) stages, namely the introduction stage by providing infographics and videographics materials, the observation stage with a visit to the Mangrove Nature Tourism Park, Angke Kapuk, North Jakarta; and the reflection stage through reflection instruments filled out by partners. Based on the results of the activity, it is known that all respondents have theoretical experience about the existence and sustainability of mangrove forests obtained from the school. Community service activities (PkM) provide new experiences in the creative process to understand the topic of PkM, namely the existence and sustainability of mangrove forest ecosystems in Jakarta. Abstrak Indonesia memiliki 3,4 juta hektar atau 24% dari total 13,8 juta hektar hutan mangrove dunia. Dalam perkembangannya, luas mangrove Indonesia terus mengalami penurunan dan tercatat seluas 637.624 hektar (18,95%) dalam kondisi kritis karena penutupan tajuk yang kurang dari 60%. Hutan mangrove bermanfaat untuk meredam gelombang besar termasuk tsunami, mencegah abrasi, menyerap karbondioksida 5 kali lebih besar daripada hutan tropis di dataran tinggi, dan sebagai habitat bagi beberapa jenis satwa liar. Dengan demikian, Indonesia memiliki peranan yang sangat signifikan bagi eksistensi dan keberlanjutan hutan mangrove dunia. Berdasarkan data tahun 2018, Propinsi DKI Jakarta memiliki 300 hektar atau sekitar 10,7% dari total hutan mangrove di Indonesia yang tersebar di Taman Wisata Alam Angke Kapuk, Suaka Margasatwa Muara Angke, Hutan Lindung Angke Kapuk dan Hutan Produksi Kamal Muara sekaligus merupakan bagian dari hutan mangrove terakhir yang tersisa di provinsi DKI Jakarta. Berdasarkan fenomena tersebut, maka diperlukan upaya untuk menjaga eksistensi dan keberlanjutan hutan mangrove khususnya di Kota Jakarta. Salah satu aktor penting dalam upaya tersebut adalah kalangan remaja dengan tumbuhnya kesadaran akan isu lingkungan. Remaja sebagai pemegang tonggak masa depan perlu memahami pentingnya eksistensi dan keberlanjutan hutan mangrove. Permasalahan yang dihadapi adalah perlunya sebuah kegiatan edukasi yang sesuai dengan karakteristik bagi remaja. Oleh karena itu, tim pelaksana menginisiasi edukasi eksistensi dan keberlanjutan ekosistem hutan mangrove bagi remaja (berusia 12 – 24 tahun) di Kampung Tanjung Gedong yang tergabung dalam Remaja Masjid At-Taufiq Tanjung Gedong dengan pendekatan Experiential Learning Discovery Journey yang dilaksanakan dalam 3 (tiga) tahap, yaitu tahap pengenalan dengan memberikan materi infografis dan videografis, tahap observasi dengan kunjungan ke Taman Wisata Alam Mangrove, Angke Kapuk, Jakarta Utara; dan tahap refleksi melalui instrumen refleksi yang diisi oleh mitra. Berdasarkan hasil kegiatan, diketahui seluruh responden telah memiliki pengalaman teoretis tentang eksistensi dan keberlanjutan hutan mangrove yang diperoleh dari bangku sekolah. Kegiatan pengabdian kepada masyarakat (PkM) memberikan pengalaman baru dalam proses kreatif untuk memahami topik PkM yaitu eksistensi dan keberlanjutan ekosistem hutan mangrove di Jakarta.

Dynamic of the Land Use and Land Cover Change in Banyuwangi Regency From 1995-2019

The land use and land cover change phenomenon has become one concern over many regions worldwide, including Indonesia. Land use and land cover change due to human activities triggered alteration terrestrial ecosystems and its services including climate control functions. The study aimed to analyze land use and land cover change in Banyuwangi regency during 1995 – 2019. Four satellite images from acquisition year 1995, 2000, 2014 and 2019 were used to analyze the spatial and temporal changes along with field observations. The classification processes of land use and land cover included determination of training areas, supervised classification, and accuracy assessment. There are 12 land use and land cover based on supervised classification as follow primary forest, secondary forest, plantation forest, mangrove forest, plantation, settlement, cropland, paddy field, shrubs, water, fishpond and barren land. The result showed during observation period of 1995 until 2019 land use and land cover which tends to decrease are secondary forest, mangrove forest, and rice fields. On the other hand, the area of settlements, shrubs and fishponds were increased significantly.

TINGKAT KESEHATAN HUTAN MANGROVE DALAM HUBUNGANNYA DENGAN PERUBAHAN IKLIM (Studi Kasus Mangrove Pesisir Timur Kabupaten Lampung Timur)

The condition of mangrove forests on the east coast of East Lampung Regency is currently experiencing degradation and has suffered a lot of damage due to various causes and problems it faces. This condition causes the role and benefits and functions of mangrove forests to decrease, especially in climate change. Therefore, to determine the condition of the mangrove forest, periodic monitoring and assessment of mangrove forest health is required. The purpose of this study was to determine the importance of mangrove forest health in climate change. To achieve this, the stages include: determining the number of plot clusters to be made, making cluster plots, measuring the health of mangrove forests based on ecological indicators of mangrove forest health, processing and analyzing mangrove forest health data using SIPUT (Assessment Information System) software. Forest Health), and categorization and health assessment of mangrove forests. The results of this study indicate that the condition of mangrove forests on the East coast of East Lampung Regency in general has a forest health condition in the medium category. So, knowing the health condition of mangrove forests will affect climate change. Forest health makes mangrove plants grow with good physiological processes so that they can absorb carbon dioxide in the atmosphere optimally. These conditions will make the environment better.