Research on the level of damage to mangrove ecosystems has been carried out in Estuarine Area Sei Jang. The purpose of this study was to determine the types of mangroves, the density and percentage of mangrove canopy cover, and the level of damage to mangrove ecosystems in the Sei Jang Estuary Area of Tanjung Pinang City. This research was conducted in March 2019. Determination of the research location using a purposive sampling method of 3 stations and using a 10 x 10 m transect for the density and percentage of mangrove canopy cover. The results found four types of mangroves namely Bruguiera gymnorhiza, Rhizophora apiculata, Rhizophora mucronata, and Ceriops tagal with density values (1.033-1.367 individu/ha) and the percentage of mangrove canopy cover with values (61.55-78.41%). For the level of damage at Station I and III are categorized (good) and Station II is categorized (Damaged).

Sei Carang waters are a mangrove ecosystem area with a fairly wide area coverage, Sei Carang waters have mangrove ecosystems. This study aims to determine the level of mangrove density and production of mangrove litter in Sei Carang. This research was conducted May-June 2022 located in Sei Carang. Observation locations were determined by survey methods and point selection using purposive sampling. Then observations using line transects using a plot measuring 10x10 m. There were 6 species found at the study site, namely: Rhizophora apiculata, Rhizophora mucronata, Bruguiera gymnorhiza, Bruguiera sexangula, Sonneratia alba, Xylocarpus granatum. The most common types were found at station 1 where there were 6 of them, and at station 3 there were only 4 types. With density levels ranging from 1633.33 ind/ha to 2300 ind/ha. And also the highest litter production value occurs at station 3 with an average value of 7.21 (gbk/m²) and the lowest occurs at station 2 with an average value of 2.27 (gbk/m²), and the parameters of the Sei Carang waters are still relatively low. good for the life of the mangrove ecosystem when compared to seawater Quality Standards Government Regulation of the Republic of Indonesia No. 22 of 2021 concerning the Implementation of Environmental Protection and Management, Attachment VII.

The mangrove ecosystem in the Sei Carang estuary waters, Tanjungpinang city is a mangrove ecosystem that has land conversion activities and leaves the environment with open land. The purpose of this study was to determine the density and regeneration rate of mangrove ecosystems on post-bauxite mining areas as seen from seedling, sapling, and trees. This research was conducted in July-October 2022. This study was conducted at four stations determined by the purposive sampling method, based on the existence of a mangrove ecosystem in which there are post-bauxite mine openings in the Sei Carang estuary waters, Tanjungpinang City. For each station, 3 plots of data were collected, with a plot size of 1x1m for the seedling category, a plot of 5x5m for sampling and a plot of 10x10m for trees. Data analysis used the formula for species density, for the regeneration rate by comparing the data from the calculation of the density of seedling, sapling and trees and then the formula for the diversity index. The results of the study found eight types of mangroves, namely Rhizophora apiculata, Rhizophora mucronata, Bruguiera gymnorhiza, Soneratia alba, Avicennia lanata, Nypa fruticans, and Lumnitzera litorea. Density values at station 1 for seedling 40,000 individual/Ha, sapling 2,667 individual/Ha, and trees 1,533 individual/Ha, at station 2 for seedling 30,000 individual/Ha, sapling 1,467 individual/Ha, and trees 500 individual/Ha, at station 3 for seedling 36,667 individual/Ha, sapling 5,200 individual/Ha, and trees 1,600 individual/Ha then at station 4 for seedling 53,333 individual/Ha, sapling 3,200 individual/Ha, and trees 2,133 individual/Ha. The level of mangrove regeneration at all observation stations is quite good.

As part of the life support system, the mangrove ecosystem in the Rawa Aopa Watumohai National Park (TNRAW) has an ecological function as a spawning ground for fish in the waters, a filter for sea water intrusion into the mainland, and an absorber of heavy metals that are harmful to life, habitat for wildlife. migratory bird shelters; as well as barrier to coastal abrasion, hurricane winds and tsunamis. Aim of this study were to determine the critical level of mangroves using the terrestrial method (field survey) and to formulate the factors causing the criticality of mangroves in TNRAW. This research uses  vegetation and descriptive analysis. The results of this study indicate that there are four families and eight species of mangroves in the research location. The four families are Meliaceae, Rhizophoraceae, Avicenniaceae and Combretacea with the dominating family was Rhizophoracea. Mangroves species found were Xylocarpus granatum K., Bruguiera gymnorrhiza L., Rhizophora mucronata Bl., Rhizophora apiculata L., Ceriops decandra, Ceriops tagal, Avicennia alba and Lumnitzera racemosa.  The highest and lowest mangrove species diversity indexes in TNRAW were the seedling and tree strata, respectively with values 1,733 and 1,570. For the critical level of mangrove land measured at the four research stations, it shows that the mangrove ecosystem at the four research station is in a damaged condition. Causal factors of mangrove land critical in TNRAW were economic factors, education and skills, and weak of supervision of the authorities.

Pangkil Village is one of the areas located on the coast of Bintan Island, Teluk Bintan District. This island has an aquatic ecosystem with abundant marine resources, one of which is the mangrove ecosystem. Mangroves are the main supporting ecosystem for life activities in coastal areas that play an important role in maintaining the balance of environmental biological cycles. This study aims to determine the condition, distribution and density level of mangroves in the waters of Pangkil Village. This research was conducted in February-March 2021. The research method is purposive sampling, which means that the research station points are chosen intentionally based on the consideration of the condition of the existence of mangroves or the density of mangroves. The research station points were determined as many as 8 stations, at each station consisting of transects and at each transect consisting of 3 sample plot plots (Transect Line Plot). The density level data was collected using a line transect measuring 10x102 which was drawn from the sea to the land and the distribution of mangroves using lansat-8 imagery. The level of mangrove density in the waters of Pangkil Village is still quite good. The results of the research on the level of mangrove density in the waters of Pangkil Village are classified as good with the distribution of mangrove areas in the waters of Pangkil Village covering an area of 40.23 ha, with an average density level of 1,033 ind/ha per station to 1,733 ind/ha. with medium and solid status based on the Decree of the Minister of the Environment No. 201 year 2004.

The study aims to determine the type of vegetation that composes mangrove forests and their zoning patterns, to know the composition of mangrove vegetation types and to determine the level of mangrove forest diversity. This study was determined based on the characteristics of the research location ranging from those close to residential areas to those located close to the beach. The method used is systematic sampling which consists of nine observation blocks and each block is divided into four circular research plots. There are 9 types of vegetation that compose mangrove forests in Wambona Village, Wakorsel District, i.e. Avicenna alba BI, Bruguiera hainnessi, Bruguiera gymnorrhiza (L.) Lamk, Ceriops tagal (Perr), Rhizophora mucronata Lamk, Rhizophora stylosa Griff, Sonneratia alba J.E. Smith, Caseolaris sonneratia (L.) Engl. and Bruguiera parviflora (Roxb.) Important Value Index (IVI) of mangrove vegetation in Wambona Village, Wakorsel District namely; 300% for tree level, pole, stake and 200% for seedling level. Diversity of mangrove vegetation types in Wambona Village, Wakorsel District as a whole is in the moderate category (moderate stability) with each tree 1.54, pole 1.57, stake 1.49 and seedling 1.64.

The plant species mangrove has been knowed to be effective for the bio-desalination process. However, there is currently no scientific evidence supporting the ability of mangrove bio-desalination when implemented through the floating method. This laboratory-scale study aimed to evaluate the bio-desalination of several mangrove species using the floating method. This study consisted of four treatments and three replicates. Treatments included a control group without mangroves (treatment A) and three treatments using mangroves (treatments B, C, and D), Bruguiera sp., Rhizophora sp., and Avicennia sp., which were positioned floating in a tank using a tray. During the eight weeks of rearing, nutrients were provided through 60 mL liquid NPK fertilization. The results showed that there was a decrease in salinity concentration in all mangrove treatments between 22.5-23.9 ppt from the initial salinity of 30 ppt. Different results were observed for the treatment without mangroves, and the salinity concentration tended to increase until the end of the research to 31.6 ppt. The highest Salinity Reduction Efficiency (SRE) was achieved by Avicennia sp.. (25.1%), followed by Rhizophora sp. (22.8%), and the lowest in Bruguiera sp. (20.3%). The results of this study showed that bio-desalination using mangroves had a significant effect on SRE, and each treatment indicated a significant difference (p<0.05). The results of this study provide initial evidence of the potential of the mangrove floating method for bio-desalination of seawater into brackish water.

Mangrove forest or better known as mangrove forest is an ecosystem found in coastal waters and has an important ecological and economic role. This study aims to measure and determine the health status of mangrove forests that grow in the waters of Berakit, Bintan based on the level of tree density. The study was conducted in August to November 2019 which was conducted at twenty station points spread from the mainland to the coastal waters of Berakit. Field data collection was performed using the quadratic transect line method, 10x10 m² plot was made along the transect line to measure the diameter of the tree at breast height (DBH) which has a trunk circumference for each mangrove tree at breast height of about 1.3 m. Mangrove health status based on the level of density of mangrove trees is included in the criteria of Good with Very Solid category. Rhizophora apiculata is a species of mangrove that grows well and has an important role in the waters of Berakit, Bintan island.

Mangroves are coastal ecosystems that have many benefits, including the ecological benefits of being a source of nutrients for marine life (aquatic biota) and a source of food for land biota. This study aimed to determine the species composition and community structure of mangrove vegetation based on the substrate type and the relationship between mangrove density and substrate texture in Borimasunggu Village, Labakang District. This research was carried out from July to August 2021 in the Borimasunggu Village, Labakkang District, Pangkep Regency. The research method is purposive random sampling which is divided into 3 stages. At each station, 3 transects/plots are determined. The study results found 3 mangrove species in Borimasunggu Village, Labakang District, based on the type of substrate, namely Rhizophora stylosa, Avicennia alba, and Sonneratia alba species. Relative Frequency (RFi) in Borimasunggu Sub-District, Labakang District, was found for all species equally, namely 33.33, the highest relative cover (RCi) was the species Rhizophora stylosa, which was 39.25, and the lowest Relative Coverage (RCi) was the mangrove species Sonneratia alba, which was 26,15. While the highest Significance Value (INP) is the mangrove species Rhizophora stylosa, which equals 148.66%, and the lowest Important Value (INP) is the mangrove species Sonneratia alba, which is equal to 70.59%. The highest relative density (RDi) was found in the mangrove species Rhizophora stylosa, which was 74.07% with a clay substrate type, followed by Avicennia alba 14.81% and Sonneratia alba 11.11% with a dusty clay substrate types.

The waters of the Sei Carang estuary are water areas that are influenced by tides and have mangrove vegetation along the waters. However, with the conversion of land functions such as bauxite mining and logging activities, the existing mangrove ecosystem is damaged. The purpose of the study was to determine the ecological characteristics of the mangrove ecosystem and to determine the level of ecological suitability of the mangrove ecosystem as a mangrove rehabilitation area in the Sei Carang estuary waters, Tanjungpinang City. This study used a purposive sampling method at 4 stations selected based on land openness and locations that allow for rehabilitation. Parameters in this study include mangrove type, substrate, salinity, tidal type, pH, current velocity, and biota objects. Based on observations, there were 10 types of mangroves found. The results of observations that have been calculated using the mangrove rehabilitation land suitability matrix show that each station can be said to be suitable for the rehabilitation area with the distribution of the suitability value of mangrove rehabilitation land showing a dominant suitability of S1 (Highly Appropriate).

The waters of the Beladeng River Muara is one of the areas in the Dompak Tanjungpinang Sub-District which has quite large potential for mangrove ecosystems. To maintain the condition of the mangrove ecosystem, it is necessary to know the structure of the mangrove community itself. The purpose of this study was to determine the types of mangroves and the structure of the mangrove community which includes the level of species density, species frequency, species closure, importance value index and mangrove canopy cover in the waters of the Beladeng River estuary, Dompak Tanjungpinang Village. This research was conducted in April-December 2022 using the Purposive Sampling method with 3 stations. In observing the mangrove ecosystem using the Transect Line Plot method measuring 10x10 m². Based on the results of the study, there were 3 types of mangroves found, namely Rhizophora apiculata, Xylocarpus granatum, and Brugueira gymnorhiza. Meanwhile, the mangrove community structure obtained the highest density at station 3 with a value of 4733.34 ind/ha. At station 1, the types of Rhizophora apiculata and Xylocarpus granatum received the same frequency values, and the highest IVI was achieved by Xylocarpus granatum. At station 2 the highest species frequency values were found in 2 species, namely Xylocarpus granatum and Rhizophora apiculata, and the highest IVI was Rhizhopora apiculata. For station 3, the 3 types of mangroves got the same type frequency value, and the highest IVI was achieved by Rhizophora apiculata. Meanwhile, the highest percentage of mangrove canopy cover was found at station 1 with good and very dense categories.