Distribution And Abundance Of Mangrove Vegetation In The Disturbed Ecosystem Of Segara Anakan, Central Java (Distribusi dan Kemelimpahan Vegetasi Bakau di Ekosistem Hutan Rusak Segara Anakan Jawa Tengah)

摘要

The Segara Anakan mangrove from 1980 up to the present has experienced heavy siltations and mangrove-tree cutting. The siltation of 4.5 million tons per year from the watershed of Citanduy River create a lot of newly formed land and shoals, which disturbed the pattern of tidal flow and tide periods. In 1997 large areas of mangroves were converted to shrimp ponds which failed and were abandon. The purpose of this research was to study the response of mangrove vegetation to the changing of the Segara Anakan ecosystem. This study compared the area which experienced only heavy siltation and tree cutting with the area experienced only tree cutting. The transect methods with quadrate plots were used in collecting data. The results showed that there were 16 species of mangrove and one aquatic macrophyte. Almost all of the areas were colonized by the shrub, Acanthus ilicifolius, and liana-shrub, Derris heterophylla. Both of these species had r and k strategies, which had coverage almost 100%, and had consecutive 83583 and 23938 densities shrubs per ha. The dominant tree species were Sonneratia alba with 485 trees per hectare and Avicennia alba with 203 trees per hectare. However, the distribution and abundance of mangrove trees were determined by the tree cutting activities, and they were not determined by the high siltation rate and salinity. The combination between heavy siltation, mangrove tree cutting, land clearing and the climate change worsen the Segara Anakan mangrove ecosystem. Therefore, the mangrove of Segara Anakan was a critically endangered ecosystem.