Struktur Dan Komposisi Vegetasi Mangrove Di Kawasan Laguna Segara Anakan Cilacap

In coastal areas, mangrove communities have many functions economically, physically, and ecologically. One of the mangrove forest areas that is experiencing rapid decline in area is the Segara Anakan Lagoon, Cilacap. The purpose of this study was to determine the structure and composition of mangrove vegetation. Vegetation data was collected by purposive sampling method and each station was made 9 sampling plots. The results found that there are 12 species consisting of 4 major mangrove families, 1 minor mangrove family and 2 associated mangrove families. In general, the mangrove tree vegetation in the eastern part of Segara Anakan is dominated by Aegiceras corniculatum with an INP ranging from 38.99-67.23%, the middle part is dominated by Nypa fruticans with an INP ranging from 47.80-70.18% and the western part is dominated by Sonneratia alba with an INP of 56.32%. Environmental quality measures include water temperature, salinity, dissolved oxygen, soil pH, water pH, TSS, total soil N, organic C, soil phosphate still support mangrove life.

The Mangrove Landscape and Zonation following Soil Properties and Water Inundation Distribution in Segara Anakan Cilacap

The mangrove zoning and landscape express the correlation between mangrove vegetation (density, biodiversity and species distribution) with environment factors like as water inundation, seatide, and soil properties. The research was conducted in Segara Anakan Lagoon to analysis community structure and mangrove landscape based on species distribution, biodiversity, environment factors, and mangrove zoning. The results showed that (a) Segara Anakan Lagoon had 4 mangrove zone's were dominated by Sonneratia alba, Rhizophora mucronata, Avicennia marina, Rhizophora apiculata, Rhizophora styllosa, and Nypa frutican; (b) the structure of ecosystem was showed by trend of mangrove ecosystem with equation y = 35.34x2 923.85x + 12817 with x = time (year) and y = mangrove area (ha), mangrove density between 1333367 ind ha-1 (West Segara Anakan) and 899–567 ind ha-1 (East Segara Anakan), dominated species were Nypa frutican, Rhizophora stylosa, Rhizophora apiculata, and Aegiceras corniculatum and mangrove biodiversity between 2,572,65 (moderate); (c) structure of environment factor showed single and semi double-type tides, water debit between 0.360.73 m s-1; water depth between 0.20–23.7 m and water inundation between 480cm; soil texture was clay and loam, soil nitrate of 1.5 mg 100 g-1, soil phosphate of 1.5 mg 100 g-1, C organic of 1.31%, soil pH of 6–7, and soil salinity of 6.5–10 ppt.

The application of Landsat imageries and mangrove vegetation index for monitoring mangrove community in Segara Anakan Lagoon, Cilacap, Central Java

The only place for estuarine-mangroves in Java Island, Segara Anakan Lagoon, experiences the vast decline of mangrove cover. Satellite remote sensing has a critical role in monitoring that change as it allows to record vast areas over time. However, most studies tend to utilize satellite data to investigate the change of mangrove areas into other land-use types rather than identify the mangrove community’s shifting. This study utilized the mangrove vegetation index (MVI) for monitoring the changes of mangrove communities at the life-form level using satellite data. The study used multi-temporal Landsat images as it has historical systematic archive data. The threshold value of the index for each class is defined by referring to the field data. The class referred to the life-form classification consisting of mangrove trees, Nypa, and understorey. The image analysis was conducted using Google Earth Engine (GEE), while R software was used for determining threshold values through statistical analysis. The result shows that the MVI can differentiate between some life forms of mangroves, with the overall accuracy reaching 78.79% and a kappa coefficient of 0.729. Further, the multi-temporal maps showed the decline of mangrove tree areas, which the understorey and Nypa community have replaced.

Tannins in mangrove plants in Segara Anakan Lagoon, Central Java, Indonesia

Hilmi E, Sari LK, Siregar AS, Sulistyo I, Mahdiana A, Junaedi T, Muslih, Pertiwi RPC, Samudra SR, Prayogo NA. 2021. Tannins in mangrove plants in Segara Anakan Lagoon, Central Java, Indonesia. Biodiversitas 22: 3508-3516. Mangrove tannin is polyphenol compound and extractive matter in mangrove vegetation. Mangrove tannins have the potentials to support paint industry, animal feed, tanners and wood adhesives industry. This research is aimed to investigate the mangrove species in Segara Anakan, Central Java, Indonesia that produce tannins, and to analyze the distribution and contents of tannin in the part of mangrove plant. A total of 342 samples from 19 mangrove species was collected from 37 sampling points in Segara Anakan. UV-Visible Spectrophotometry was used to analyze the tannin content in the samples. The results showed that the tannins contained in bark and stems were higher (66.6%) than those in leaves (33.4%). Mangrove vegetation can be classified into five classes in terms of tannin percentage with Heritiera littoralis, Nypa fruticans, and Rhizophora mucronata had highest tannin percentage. The clustering analysis of mangrove tannin showed that Ceriops decandra-Ceriops tagal, Acacia auriculiformis-Sonneratia alba, Sonneratia caseolaris-Xylocarpus granatum, and Avicennia marina-Rhizophora apiculata had high similarity of tannin percentage. The distribution of tannins in mangrove species is as follow: 0.59-10.14 kg trees-1 (bark and stem of mangrove diameter > 10 cm) and 0.20-3.74 kg trees-1 (leaves of mangrove diameter > 10 cm) until 8.84-158.96 kg trees-1 (bark and stem of mangrove diameter > 40 cm) and 4.60-91.65 kg trees-1 (leaves of mangrove diameter > 40 cm). R. mucronata and R. apiculata had the highest total tannin content, ranged between 386.60-460.38 kg trees-1.

The Sedimentation Impact for the Lagoon and Mangrove Stabilization

Sedimentation causes land accretion, silting river water, lagoon, and mangrove degradation. The current study aims to analyze the potential and the impact of sedimentation toward the potential of the lagoon and mangrove ecosystem in Segara Anakan Lagoon. The research methods used mapping analysis, total suspended solid analysis (TSS), sedimentation rate analysis, biodiversity analysis, and mangrove covering. The result showed that (1) the value of TSS between 0.25-1,16 g L-1 (2) sediment flux between 6,8 - 257,7 g m-2s-1 (3) annual rate of sedimentation in West Segara Anakan Lagoon (W-SAL) between 13.82 – 15.49 m yr-1. (4) The effects of sedimentation were (a) the remaining lagoon of West Segara Anakan Lagoon (W-SAL) which was 1.200 ha, (b) land accretion in W-SAL between 27.24 – 160.18 m (1994 – 2003) and 20.91 – 107.55 m (2003 2014), (c) the remaining mangrove of SAL less than 2594 ha (d) the mangrove diversity ranged between 0.48 – 1.71 (low – moderate), (e) the mangrove density of trees were 46 - 205 trees ha-1 (degraded) (5) mangrove landscape was developed to reduce the impact of sedimentation, especially the first zone of mangrove landscaping was dominated by Aegiceras Floridum, Avicennia Alba, Avicennia Marina, Sonneratia Caseolaris, and Sonneratia alba.