asyuni M, Gultom K, Fitri A, Susetya EA, Wati R, Slamet B, Sulistiyono N, Yusriani E, Balke T, Bunting P. 2018. Diversity and habitat characteristics of macrozoobenthos in the mangrove forest of Lubuk Kertang Village, North Sumatra, Indonesia. Biodiversitas 19: 311-317. Mangrove plays an important role in coastal ecosystems including ecological, social, and economic aspects. This study aimed to determine the diversity of macrozoobenthos and water quality based on diversity index (H’), similarity Index (E), and dominance index (D) in the mangrove of Lubuk Kertang Village North Sumatra, Indonesia. The samples of macrozoobenthos (biological parameter) and water quality (physical and chemical parameters) were collected from fifteen plots in three different stations. Macrozoobenthos were collected in 1 m × 1 m transect in the mangrove forest. The biota was taken by using a shovel, inserted into a plastic bag, and identified. Results showed that eight species of macrozoobenthos were found and classified into three classes of Gastropod, Bivalvia, and Malacostraca. The highest diversity index (H′) of macrozoobenthos was found at Station II (2.39), the highest evenness index (E) was located at Station I (0.54), and the highest dominance index (D) was found at Station II (0.34). Principal component analysis (PCA) was used to determine the habitat characteristics of macrozoobenthos. PCA confirmed that station III was a habitat with suitable characteristics for the life of macrozoobenthos indicating the negative axis. The present study suggested four parameters namely salinity, clay temperature, and dissolved oxygen that should be preserved to support the survival of macrozoobenthos in the mangrove forests.

Basyuni M, Wasilah M, Hasibuan PAZ, Sulistiyono N, Sumardi, Bimantara Y, Hayati R, Sagami H, Oku H. 2019. Salinity and subsequent freshwater influences on the growth, biomass, and polyisoprenoids distribution of Rhizophora apiculata seedlings. Biodiversitas 20: 288-295. This study described the growth, biomass, and polyisoprenoids (polyprenol and dolichol) distribution of Rhizophora apiculata seedlings under saline and subsequent fresh water treatment. Propagules of R. apiculata were collected from Pulau Sembilan, Langkat, North Sumatra and were grown in 0.0%, 0.5%, 1.5%, 2.0%, and 3.0% salt concentrations for three months. After three months planted in a glass house, R. apiculata seedlings were divided into two groups and grown for another three months. The first group was continuously grown under the saline condition and the second was moved to fresh water to recover from the saline condition. The leaves, stems, and roots of R. apiculata seedlings were harvested after six months of cultivation. Polyisoprenoids alcohol was isolated from the leaves and roots of R. apiculata seedlings and analyzed using two-dimensional thin layer chromatography. Growth parameters measured were height and diameter of R. apiculata seedlings. The height of R. apiculata seedlings was significantly affected by salinity levels of 2.0%, 3.0% and 3.0% → 0.0%. The arrow (→) denoted fresh water recovery treatment. The best height and diameter of R. apiculata seedlings were observed in 0.5% salt concentration. Salinity treatment and re-adaptation into freshwater significantly influenced the leaves area (2.0%, 3.0% and 3.0% → 0.0%), fresh weight of stem (3.0% and 3% → 0.0%) and stem dry weight (3% → 0.0%). Distribution of polyprenols and dolichols in the leaves and roots of R. apiculata seedlings were categorized as type I, where dolichol was dominant over polyprenol. Under salinity and subsequent fresh water recovery treatments (0.0%, 1.5%, 1.5% → 0.0%, 3.0%, and 3.0% → 0.0%), the carbon chain length of dolichol in the leaves and in the roots was, respectively, C85-C100, C85-C100, C85-C105, C85-C100, C85-C95 and C85-C105, C85-C105, C85-C105, C85-C110, C85-C100. These data suggested the significant role of polyisoprenoids in mangrove plants to withstand salt stress and or water stress.

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Forests are a significant part of the global carbon cycle. Forests sequester carbon by conducting photosynthesis, which is the process of converting light energy to chemical energy and storing it in the chemical bonds of sugar. Carbon sequestration through forestry has the potential to play a significant role in ameliorating global environmental problems such as atmospheric accumulation of GHG's and climate change. The present investigation was carried out to determine carbon sequestration potential of hybrid Eucalyptus. This study was conducted primarily to develop a prediction model of carbon storage capacity for plantation forest of hybrid Eucalyptus in Aek Nauli, Simalungun District, North Sumatera. Models were tested and assessed for statistical 2 validity and accuracy in predicting biomass and carbon, based on determination coefficient (R) and correlation coefficient (r), aggregative deviation percentage (AgD), and the average deviation percentage (AvD). The best 0,876 (0,094) general model to estimate the biomass of hybrid Eucalyptus was Y = 1351,09x .e. Results showed that hybrid Eucalyptus had an average above-ground biomass in year 0 (the land without the eucalyptus trees) up to year 3 as-1

High rate of deforestation occurred in Sumatra Islands had been allegedly triggered by various factors. This study examined how the deforestation pattern was related to the typology of the area, as well as how the deforestation is being affected by many factors such as physical, biological, and socioeconomic of the local community. The objective of this study was to formulate a spatial model of deforestation based on triggering factors within each typology in Sumatra Islands. The typology classes were developed on the basis of socioeconomic factors using the standardized-euclidean distance measure and the memberships of each cluster was determined using the furthest neighbor method. The logistic regression method was used for modeling and estimating the spatial distribution of deforestation. Two deforestation typologies were distinguished in this study, namely typology 1 (regencies/cities with low deforestation rate) and typology 2 (regencies/cities with high deforestation rate). The study found that growth rate of farm households could be used to assign each regencies or cities in Sumatra Islands into their corresponding typology. The resulted spatial model of deforestation from logistic regression analysis were logit (deforestation) = 1.355 + (0.012*total of farm households)-(0.08*elevation)-(0.019*distance from road) for typology 1 and logit (deforestation) = 1.714 + (0.007*total of farm households)-(0.021*slope)-(0.051*elevation)-(0.038* distance from road) + (0.039* distance from river) for typology 2, respectively.

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Abstract. Karniati R, Sulistiyono N, Amelia R, Slamet B, Bimantara Y, Basyuni M. 2021. Mangrove ecosystem in North Sumatran (Indonesia) forests serves as a suitable habitat for mud crabs (Scylla serrata and S. olivacea). Biodiversitas 22: 1489-1496. Mud crabs (Scylla serrata and Scylla olivacea) are often found in muddy substrates associated with mangrove vegetation. The habitat of these crabs ranges from tropical estuaries to sheltered subtropical areas, riverbanks, lower river traits, and intertidal areas. These crabs have an important economic value, and it increases the income of the communities living around the mangrove area. This study aims to obtain more information on the environmental factors of habitat for mud crabs (S. serrata and S. olivacea): insights on the effects of abiotic and biotic factors and potential economic value, in the village of Lubuk Kertang, Langkat, North Sumatra, Indonesia. Data were collected by measuring abiotic factors (temperature, pH, salinity, dissolved oxygen, mud depth, distance from the river) and biotic factors (mangrove stand density through canopy cover). The dataset was analyzed using a binary logistic regression analysis with a stepwise method. Results showed that the abiotic factors that contributed to the presence of the mud crab were dissolved oxygen and a mud depth of 68.7%. Meanwhile, the remaining 31.3% that contributed to the presence of mud crabs were abiotic factors (temperature, pH, salinity, distance from rivers) and biotic factors (stand density through canopy cover). The present study suggests that dissolved oxygen and mud depth have an important function in predicting the presence of mud crabs.

Abstract. Molecular cloning of five oxidosqualene cyclases (OSC) genes from Bruguiera gymnorrhiza, Kandelia candel, and Rhizophora stylosa had previously been cloned, characterized, and encoded mono and -multi triterpene synthases. The present study analyzed protein modelling of triterpene synthase genes from mangrove using Phyre2 and Swiss-model. The diversity was noted within protein modelling of triterpene synthases using Phyre2 from sequence identity (38-43%) and residue (696-703). RsM2 was distinguishable from others for template structure; it used lanosterol synthase as a template (PDB ID: w6j.1.A). By contrast, other genes used human lanosterol synthase (1w6k.1.A). The predicted bind sites were correlated with the product of triterpene synthase, the product of BgbAS was -amyrin, while RsM1 contained a significant amount of -amyrin. Similarly BgLUS and KcMS, both main products was lupeol, on the other hand, RsM2 with the outcome of taraxerol. Homology modelling revealed that 696 residues of BgbAS, BgLUS, RsM1, and RsM2 (91-92% of the amino acid sequence) had been modelled with 100% confidence by the single highest scoring template using Phyre2. This coverage was higher than Swiss-model (85-90%). The present study suggested that molecular cloning of triterpene genes provides useful tools for studying the protein modelling related regulation of isoprenoids biosynthesis in mangrove forests.