Stand composition and structure of Rubroshorea curtisii in a lowland Dipterocarp remnant forest of Bukit Tiban, Riau Islands, Indonesia

Abstract. Susilowati A, Wijaya K, Mawazin, Rachmat HH, Lismayati Y, Kurniawan H, Ginting IM. 2024. Conserving dipterocarps biodiversity in remnant forests of small islands in Batam Island, Indonesia. Biodiversitas 25: 726-733. The protected forest of Sei Harapan is a remnant forest in Batam Island, the Riau Islands Province, Indonesia and one of the keruing (Dipterocarpus spp.) habitats on Sumatra Island. Illegal logging for its wood and land degradation have significantly reduced the keruing population. The objective of this research was to assess the diversity of keruing species and floristic composition in the Sei Harapan Protected Forest. This study employed a vegetation analysis method using purposive sampling with plotted lines and the transect placement based on the keruing position. The research revealed more than 70 species, three of which were Dipterocarpaceae species, including Vatica pauciflora, Shorea curtisii, and Dipterocarpus rigidus. D. rigidus had the highest IVI at the sapling (52.80%) and pole (67.22%). However, D. rigidus ranked 13th in the seedling stage, with an IVI of 5.79%. The diversity index was high at the seedling stage (3.73), moderate at sapling (2.25), pole (2.76), and tree stage (2.89). The evenness index was high at all growth stages, with values of 0.94 (seedling), 0.98 (sapling), 0.91 (pole), and 0.81 (tree). The richness index at the seedling, pole, and tree stage were categorized as high, with values of 10.40, 5.39, and 7.09, respectively, whereas the richness index at the sapling stage was moderate at 3.51. The study finding pointed out that the existence of Sei Harapan remnant forest requires to be preserved considering its essential function for preserving high economic value tree species, especially Dipterocarp. The comprehensive conservation effort for dipterocarps species, is crucial considering the research findings revealed a problem of continuity of species regeneration and the emergence of new pioneer species as the consequence of anthropogenic disturbance.

Abstract. Susilowati A, Rachmat HH, Yulita KS, Wijaya K. 2023. Floristic composition and structure of Eurycoma longifolia habitat in Muka Kuning Nature Tourism Park, Riau Islands, Indonesia. Biodiversitas 24: 2836-2842. Eurycoma longifolia Jack, locally called as pasak bumi,is a popular medicinal plant which is known to have properties in curing various diseases. The root of E. longifolia is the organ that has the highest aphrodisiac content so hunting for the roots of E. longifolia destructively causes a significant population decline. Information regarding vegetation community around the habitat of this species is crucial in determining appropriate conservation actions. Muka Kuning Nature Tourism Park (TWA) located in Batam Island, Riau Islands Province is one of the natural habitats of E. longifolia, yet information regarding the state of vegetation in this area has not been obtained. This study aims to determine the floristic composition and structure of vegetation in the habitat of E. longifolia in Muka Kuning Nature Tourism Park focusing on the parameters of Important Value Index (IVI) and biodiversity indices. Vegetation analysis was applied using purposive sampling method based on the presence of E. longifolia individuals. The results showed that the IVI of E. longifolia at the growth stage of seedlings, saplings, poles and trees were 18.1%, 21.9%, 12.14% and 0%, respectively. No individual E. longifolia was found at the tree level which might be attributable to the habitus of this species which is small-sized tree or woody shrub with maximum height of 15 m. The vegetation community at the studied area had Shanon-Wienner diversity index (H') from 2.27 to 3.12 and the Evenness index from 0.88 to 0.98, which is categorized as high. The results of this study imply that the natural habitat of pasak bumi in the TWA Muka Kuning is classified as good and tighter area protection is highly recommended to protect valuable biodiversity in it including E. longifolia.

Conserving natural forest resources is essential for climate change mitigation and biodiversity protection, requiring a clear understanding of species composition and forest stand structure. This study assessed the floristic composition, diversity, and structure in the northern part of Amani Nature Forest Reserve (ANFR), where forest landscape restoration (FLR) efforts are ongoing, yet baseline ecological data remain limited. Systematic random sampling was employed using 42 concentric circular plots (15 m radius) across two forest clusters with differing disturbance histories. Data on species identity, diameter at breast height (DBH), height, and regeneration classes were recorded and analyzed using importance value index (IVI), Shannon–Wiener diversity, ANOVA, and hierarchical clustering. A total of 843 individuals, representing 97 species and 55 families, were documented. The northeastern cluster, which experienced less disturbance, exhibited higher species richness (72 species) compared to the northwestern cluster (64 species). Dominant species differed by cluster, with Ocotea usambarensis (IVI = 39.28%) prevailing in the northeast and Syzygium cumini (IVI = 24.59%) in the northwest. Regeneration analysis revealed more seedlings (82) and, despite equal raw counts, there were significantly greater sapling abundance (58) in the northwestern cluster, whereas tree abundance was significantly greater in the northeastern cluster (326 individuals). Diversity indices were significantly higher in the northeast, with a Shannon index of 2.87 ± 0.0424 ( p = 0.0078) and evenness of 0.956 ± 0.0089 ( p = 0.0018). Structurally, the northeastern cluster had higher stem density (288.39 ± 9.85 stems/ha) and basal area (34.74 ± 8.50 m 2 /ha). Diameter class distribution followed a normal “J” shape in the northeast and a reverse “J” shape in the northwest, indicating structural imbalance. Community analysis identified five plant assemblages, with the northeastern cluster supporting more diverse and compositionally distinct communities. These results suggest that FLR efforts have been more effective in the northeastern cluster. Addressing these ecological, socioeconomic, and policy challenges will help ANFR achieve lasting benefits and support Tanzania’s AFR100 restoration commitments. These results highlight the importance of aligning ANFR restoration with Tanzania’s National Forest Policy and AFR100 targets to ensure both ecological and socioeconomic benefits.

The current mitigation efforts of human trafficking fail to combat cross-border trafficking in the sea. On the other hand, most of the studies in human trafficking have not dealt with the context of transporting victims via seaport. This paper attempts to critically discuss the process and consequences of transporting victims of human trafficking via illegal seaport. Part of the objective is to propose compatible tech tools to anticipate potential victims. A qualitative approach was employed since investigating human trafficking in Riau Islands' seaports needs a robust research method. Thus, a case study is selected to focus on a single exit point phenomenon for sending migrant workers who have been identified as a group at high risk of human trafficking. Riau Islands, specifically Bintan Island and Batam Island, were selected as samples of case studies because these are critical locations for sending and repatriating victims. The current study found that an archipelago country like Indonesia deals with multifaceted challenges in combating human trafficking. Moreover, there is a significant shift in human trafficking crime from recruiting to executing due to the cyber world's invention. One unanticipated finding is that social networks and cybercrime have expanded the possibilities for supplying victims. This study contributes to research on human trafficking by introducing tech tools that may help overcome the problems.

While extensively studied in the 1990s, research on the electrical and electronics (E&E) industry in Singapore and the proximate areas of Indonesia has dwindled. Focusing on the E&E sector in the island of Batam (Riau Islands Province, Indonesia), we examine the industry’s recent evolution, in particular its ‘robustness’—its durability and capacity to adapt to adverse events. As to the explanatory factors accounting for its robustness, we evaluate the role of agency as opposed to conventional approaches that focus on structure. Our findings show that, in Batam, the E&E industry’s robustness has started to suffer. While there is evidence that structural factors are at work, we argue that agency in the form of institutionally-embedded perspectives and behaviour of actors at the sub-national level also plays a role. Because the promotion of economic diversification through investment in new sectors is easier and more lucrative than upgrading and deepening of firm capabilities in existing sectors, agents privilege the former at the cost of the latter. At the end of the day, regional resilience is undermined, rather than reinforced as evinced by the recent atrophy of Batam’s E&E industry.

Lubis MZ, Anurogo W, Hanafi A, Kausarian H, Taki HM, Antoni S. 2018. Distribution of benthic habitat using Landsat-7 Imagery in shallow waters of Sekupang, Batam Island, Indonesia. Biodiversitas 19: 1117-1122. Shallow sea waters are one region that has high dynamics and an important role both economically and ecologically. Batam Island one of the islands in Indonesia is rich in the ocean in Riau Islands Province, Indonesia, and surrounded by small islands.We conducted classification and correction of water column using Lyzenga formula, to see benthic habitat in Sekupang waters, Batam Island, Indonesia. This research uses remote sensing method with Landsat-7 image data, on data recording that is dated December 16, 2016. The purpose of this study is to obtain information on the distribution and extent of sand, dark sea, and coral reefs on Batam Island shallow waters of Sekupang. By using the formula of Lyzenga algorithm, the value of ki/kj is 0.404, by looking at the color change corresponding to the channel. Research result of classification in the shallow coastal waters of the island of Batam in Sekupang with the area is sand with 27.64 % (3.443 ha), cloudy sea with an area of 30.94% (3.854 ha), and coral reefs with an area of 41.43% (5.161 ha).

Beljai M, Worabai MS. 2018. The structure and composition of vegetation and amphibian diversity in Arfak Mountain, West Papua. Pros Sem Nas Masy Biodiv Indon 4: 1-12. The forest formation around Didouhu River, Arfak Mountain District, West Papua Province, Indonesia is a habitat for a number of species of plants and animals of the class of amphibians that are not yet known scientifically. Therefore, information and data on vegetation structure and composition and amphibian diversity in the area are needed. The purpose of this research is to know the structure and composition of vegetation and the diversity of amphibian species in the forest area around Didouhu River. Vegetation data were collected using a combination method of path method and line plot systematic method, while amphibian type data were collected using visual encounter survey method. Vegetation data were analyzed using vegetation analysis method, while amphibian diversity was analyzed by using Shannon-Wiener index (index of species diversity), evenness index, and Jaccard similarity index (similarity index). From the result of vegetation analysis, there are 65 types of vegetation covering 50 types of seedlings with a density of 17,500 individuals/ha, 50 types of sapling with a density of 4,085 individuals/ha, 42 types of pole with density of 506 individuals/ha, and 28 species of tree level with a density of 108 individuals/ha. There were eight types of vegetation with the highest importance value index (IVi) which dominates between three and four growth phases, namely Dodonaea viscosa (IVi=166,80%), Lithocarpus ruvofilosus (IVi=83,68%), Lithocarpus aspericulata (IVi=69,47%), Rhus lamprocarpa (IVi=54.44%), Melicope sp. (IVi=40,41%), Drimys piperita (IVi=39,91%), Pouteria sp. (IVi=34.29%), and Galbulimima belgraveana (IVi=31.85%). The eight types of vegetation are the principal founders of plant communities in forest ecosystems around the Didouhu River. Amphibians are found in four types, namely Litoria arfakiana, Asterophrys sp., Rana grisea, and Lechriodus platyceps. The diversity of amphibian species in the study sites was moderate (H '= 3.14) with low species inter-species similarity (S = 0.17). The level of evenness is high (E = 0.91), where there is one type of L. arfakiana found in two research sites (locations A and B). Overall, the location of the study is quite damp, lots of puddles, riparian vegetation quite dense, and has rocky soil conditions and litter, making it a suitable habitat for amphibians of the Order of Anura.

The potential for ecotourism in the Riau Islands has increased after the Covid 19 pandemic passed, with the largest number of foreign tourist destinations on Batam Island. One of the ecotourism potentials that can be developed is land forest management as part of the forest and land rehabilitation program by BPDASHL Sei Jang Duriangkang Riau Islands in Mangsang Village, Sei Beduk District. Several ecotourism activities have been developed but have not been managed well. One of the efforts to manage sylvo-ecotourism in Mangsang can be done by identifying sylvo-ecotourism potential. Identification was carried out by surveying and exploring the forest area around Mangsang Hill, Sei Beduk District. The data collected includes the type and condition of land forests, unique, interesting and rare types of fauna as well as potential tourism activities that can be developed. Based on the results, it was found that there is sylvo-ecotourism potential for sports spots such as downhill, tracking; natural spots such as the Mangsang waterfall and views of sunset, sunrise and views of the coast and islands around Batam City; as well as agricultural fruit harvest spots. It is feared that land clearing activities around the Predatory Hill area for settlement will cause sedimentation due to erosion around the Tembesi Reservoir.

<p><strong>Background. </strong>The aim of this research is to identify plant species that constitute the vegetation and species abundance in ex-bauxite mining land in Tanjungpinang City, Riau Islands Province, Indonesia. <strong>Objective</strong>. To identify vegetation composition and species abundance on ex-bauxite mining land. <strong>Methodology </strong>A nested plot sampling method was used to randomly identify the species at two ex-bauxite mining sites (Dompak and Senggarang) and a non mining site in Senggarang. Each site, measuring 1x1 meter, with 12, 14, and 12 plots were also examined using the understory plant samples. Furthermore, observations were made on the morphological characteristics of plants to determine the herbarium preparation process, identify the species, and validate the scientific names of plants. <strong>Results. </strong>The research found that understory plants in the three sites consisted of 17 families with 24 species with the Cyperaceae family contributing five more species than any other families. The three species with the highest importance value indices at each site were: at Dompak namely, Poaceae (51%), <em>Waltheria indica </em>(26.50%), and <em>Dicranopteris linearis </em>(21.80%); at Senggarang, <em>Palhinhaea cernua </em>(37.10%), <em>D. linearis </em>(37.02%), and Poaceae (36.37%); and the not a former bauxite mine site in Senggarang is <em>D. linearis </em>(70,00%), Poaceae (64.00%), and <em>Melastoma malabathricum </em>(23.07%). The Sorensen similarity index values for the three locations were 46.7% for the Dompak and Senggarang sites, 41.7% for the Dompak site and the non-former bauxite mining site, and 50% for the Senggarang site and the non-former bauxite mining site, respectively. <strong>Implications. </strong>Morphological species identification and herbarium preparation were used to identify and validate the vegetation composition on the former bauxite mining land in Tanjungpinang. The data obtained is valuable for understanding the natural recovery patterns of the land and provides insight into species suitable for further rehabilitation in the Riau Islands. The result showed that invasive species such as Poaceae and <em>Dicranopteris linearis </em>should be prioritized in revegetation programs. The research also addresses a gap in scientific knowledge regarding critical species for the successful rehabilitation of degraded lands. <strong>Conclusion. </strong>The research found that understory plants in the three sites consisted of 17 families with 24 species. The importance value index at each site was 51% for Poaceae (at Dompak), 37.10% for <em>P. cernua </em>(at Senggarang), and 70% for <em>D. linearis </em>(at non-former bauxite mine site in Senggarang). The Sorensen similarity index values for the three sites were 46.7%, 41.7%, and 50% for the Dompak and Senggarang sites, Dompak, and the non-former bauxite mining sites. </p>

This study was conducted in December 2019, which was located in Dompak Village, Bukit Bestari District, Tanjungpinang City, Riau Islands Province. The purpose of this study was to determine the species composition and condition of mangrove forests based on the value of density, canopy cover and the importance value index of mangroves. The survey method was used in this study, where the data collected was primary data. There are 10 types of mangroves including Avicennia lanata, Bruguiera gymnorrhiza, B. cylindrica, Rhizophora apiculata, R. stylosa, Nypa fruticans, Sonneratia alba, Xylocarpus granatum, Scyphiphora hydrophyllacea and Hibiscus tiliaceus. Mangrove density was in good condition with moderate to dense ​​ranging from 1344.44-1555.56 ind/ha. Canopy cover was in good condition ​​ranging from 61.49-68.47%. The highest importance value index was R. apiculata with a value of 140.32% and the lowest was B. cylindrica with a value of 4.29%.

This study was conducted to determine the characteristics of orchid host trees, the diversity of epiphytic orchids (Orchidaceae), and the preservation of host trees and epiphytic orchids in the Lununianam protected forest area. This research was conducted in Lununianam Protection Forest, Fatu'ulan Village, Ki'e District, South Central Timor Regency, East Nusa Tenggara Province. Which is carried out for 1 month, from November to December 2022. This study used purposive sampling methods, surveys, and cruising paths with data analysis using qualitative descriptive and quantitative descriptive analysis. Host tree data was processed using vegetation analysis formulas and orchid data was processed using the Shannon wiener (H') diversity index formula.
 The results showed that there were 5 species of host trees found in the study site, namely forest guava (Syzygium pycnanthum), Matani (Pterocarpus indicus), Tahi (Celtis wightii planch), Kamala (Mallotus philippensis), Jenitri (Elaeocarpus ganitrid). Host trees found in Lununianam Protection forest have the characteristics of large hard and rough bark, have a height range of 12-30 m, and bark overgrown with moss, The results of vegetation analysis of host tree species with the highest Important Value Index namely Syzygium Pycnanthum and Elaeocarpus ganitrus have the lowest Important Value Index. Orchids found in the sampling plot in the Lununianam Protection Forest contained 8 species of epiphytic orchids, namely Dendrobium Sp, Vanda insignis, Eria multiflora, Flickingeria grandiflora, Trichoglottis bipenicillata, Pholidota carnea, Appendicula reflexa Blume, and Ceologyne speciosa. The calculation of Shannon Wiener's diversity index of 1.57 (H') is classified as medium (1<H'<3). The most common type of orchid found is the type Eria multifora with a total of 168 individuals and the type that is less commonly found is Appendicula reflexa Blume with 4 individuals.

Restoring the degraded areas with vegetation cover is an optimal strategy to mitigate land degradation. The objective of this study was to examine the composition and structure of woody vegetation in community and state forests in Tehuledere District, South Wollo, Ethiopia. The vegetation data were collected by sampling a total of 40 systematically laid sample plots (i.e. 20 samples in each forest type) and analyzed to determine woody species composition (i.e. number of species, frequency, density, dominance, and importance value index) and forest structure (i.e. diameter distribution, basal area, and biodiversity index). The vegetation structure was described by diameter class using inverse J-shaped as this type of distribution considered being indicative of a stable population structure or good regeneration status. The results revealed that significantly greater densities of seedlings and saplings were found in the community forest than that of the state forest. Moreover, a total of 45 woody species, representing 29 families were recorded in this forest. However, 29 woody species, representing 25 families were only found in the state forest, suggesting that 25 woody species were common in both forest types. However, 20 woody species were found only in the community forest, whereas only three species were exclusively obtained in the state forest. Woody plant densities were 10,881 and 9,501 individuals’ ha−1 in community and state forests, respectively. The result suggested that Juniperus procera was the most dominant species in both forest types. The community forest had a diversity value of 2.26, while the corresponding value for the state forest was only 2.07. Overall, as compared to the state forest, the community forest had a better status in several biological parameters. Generally, the results emphasize the importance of the relative advantage of the community forestry approach to restore, enhance, and maintain (e.g. enrichment planting, pruning, and selective cutting) the forest resources over the conventional or protectionist way of the state forest management. Therefore, intervention for legal framework and institutional development particularly through formal recognition of people’s ownership and right over the conservation management of forests is essential toward sustainable forestry.

Although oak woodlands are a characteristic landscape component in the Swat Hindukush Mountain ranges, little is known about their current or historical stand population structure and regeneration dynamics related to environmental variables. Therefore, the present study assessed the stand structure, regeneration status, and relationship of oak communities with environmental variables. The study assessed 30 oak-dominated forest sites using the quadrates method, sampling 300 quadrates for evaluating the phytosociological and environmental variables. The stand structures of forests were dominated by four oak species, i.e., Quercus incana, Quercus baloot, Quercus dilatata, and Quercus semecarpifolia, distributed along with the elevation. The lower elevation stand structures were most diverse and dominated by Q. incana, having higher stand parameters, i.e., importance value index, basal area, and density. In contrast, the higher-elevation stand structures were dominated by Q. semecarpifolia, having stand parameters in moderate measures, while those at intermediate elevations have lower stand parameters. The environmental variables were negatively correlated with the stand structures, i.e., elevation (r = −0.51), precipitation (r = −0.47), and relative humidity (r = −0.77), whereas soil nutrients such as Potassium concentration have a significant negative relation with stands structure (r = −0.66) indicating their vital role in sustaining the oak communities. The communities were fairly regenerated, with an age structure between 12–36 years, indicating young communities. These results concluded that the observed wide range of variability in stand characteristics reflects the mechanisms that have shaped them. The recent anthropogenic factors, i.e., military operations and natural hazards such as the flood of 2010, have deliberately affected the communities under natural restoration.

Bulang districts Batam Islands of Riau province (Riau Islands), its consists of many islands with as well as having the potential diversity of coastal marine life in particular kinds of macro algae or seaweed. Conducted research aimed to determine the structure of macro- algal communities in the intertidal zone islands. The results of the identification of algal species found 16 species are: the Order of Chlorophyceae as 6 spesies; Order Phaeophyceae as 2 spesies; and Order Rhodophyceae as 8 spesies. The community structure at the five stations showed the highest values were found in the island of dominance Cicir (D ' = 0.79) , uniformity index values on Tengah Island (E ' = 0.99) , while the island Balak had the highest diversity index (H ' = 0.88) , with the abundance patterns of population structure on the island is pretty good Central . Results of correlation analysis of regression between IVI types of algae with the conditions of environmental quality suggests that there is a significance (Fhit ˃ F table and the value of r = > 90 %) between IVI algae Halimeda sp and Cryptarachne polyglandulosa at each station with a temperature parameter surface (⁰C) , depth temperature (⁰C) and pH values. Keywords : Algae, Community Structure, Important Value Index.

Batam Island is built into the Free Trade since 1970 by the Batam Authority, but in 2000 stood Batam City Government, to 2016 the economy grew 6,5%, but since 2017 dropped to 2%, this phenomenon should be a study. The population is employee environment Batam Area Concession Agency, APINDO, BKPM, Batam City Government Employees, the Chamber of Commerce, Community and students. Total respondents 190 respondents sampled (census method). Data Analysis was perfomed using Structural Equation Model (SEM). The software used for the structural analysis is AMOS 22, descriptive analysis using SPSS version 22.0. Geographical Utilization variable determination to variable investmenthas standardized estimate of 0,121<0,50 with CR identical to the value t-tes) CR = 1,749<2,00 on probability = 0,080 > 0,05 is negative not significant. Determination variable to variable Infrastructure Investmenthas standardized estimate 0f -0,816<0,50 with CR identical to the value t-test = -2,013<2,00 on probability = 0,044 < 0,05 is significantly negative. Determination of laten variable to variable organizations Resource investment has standardized estimate of 0,972>0,50 with CR identical to the value t count = 7,336>2,00 on probability = ***<0,05 is a significant positive. Utilization variable determination to variable Geographical Area Developmenthas standardized estimate of 0,020<0,50 with CR idential to value t count = 0,257<2,00 on probability = 0,797> 0,50 is negative not significant. Determination variable to variable Regional Development Infrastructure is has standardized estimate of 0,247<0,50 with CR idential to value t count = 2,248>2,00 on probability = 0,025<0,50 significantly positive. Organization Resource variable determinan variable is the Regional Developmenthas standardized estimate amounted to -0,224<0,50 with CR identical to the value t –test = -1,100<2,00 on probability = 0,272>0,50 not significant. Determination variable to variable investment Regional Developmenthas standardized estimate 0,927>0,50 with CR identical to the value t count = 4,900>2,00 on probability = ***<0,05 is a significant positive.