Colonization of mangrove forest at abandoned shrimp-pond of Segara Anakan, Cilacap

• Main Author: Djohan, Tjut Sugandawaty
• Format: Article PeerReviewed
• Language: English
• Published: Sekolah Pascasarjana Universitas Gadjah Mada 2014
• Subjects: Biological Sciences
• Online Access: https://repository.ugm.ac.id/101182/1/Colonization%20of%20Mangrove%20Forest%20at%20Abandoned%20Shrimp-Pond%20of%20Segara%20Anakan-Cilacap%2C%20Tjut%20S.%20Djohan.pdf; https://repository.ugm.ac.id/101182/
• Institution: Universitas Gadjah Mada

During the 1996 to 1997, large areas of mangrove forest in the Segara Anakan were cleared and converted into intensive shrimp-ponds. After one to two years these shrimp-ponds failed and were abandoned. These abandoned ponds created large gap area and canopy gap, and was considered as big disturbance to the mangrove forest, which were colonized by mangrove shrubs and liana. The Segara Anakan mangrove was also experienced heavy siltations, and tree cuttings from the remnant of the mangrove trees. This research was to study the colonization of mangrove vegetation at the abandoned-shrimp pond. Vegetation data were collected using quadrate plots of 25 m x 25 m with 4 replicates at each site. The water qualities were also studied. The results revealed that the mangrove forests were composed of two layers, canopy tree and floor-vegetation. The gap areas triggered the pioneer species of mangrove shrubs and liana, Acanthus ilicifolius and Derris heterophyllato colonized and dominated 100% of the mangrove forest floor. The mangrove trees were rare and consisted of natural and planted tree species. The natural-tree were Sonneratia alba, Avicennia alba, and sapling of Aegiceras corniculatum inconsecutively varied 56-136; 4; and 4 individual per ha. The planted tree was Rhizophora apiculata, 4-12 individual per ha, at the island of the ponds. These trees and saplings were entangled by the liana mangrove, which disturbed their growth. The A. ilicifolius and D. heterophylla out competed and prevented the mangrove tree-propagules to grow, and they colonized and characterized those abandoned shrimp-ponds, which threatened the sustainable of the Segara Anakan mangrove ecosystem. Key words: canopy-gap, mangrove tree, Acanthus, Derris Kolonisasai hutanbakau di tambak udang rusak Segara Anakan, Cilacap Pada tahun 1996-1997, hutan bakau di Segara Anakan dalam skala luas ditebang dan diubah fungsinya menjadi tambak udang. Tambak udang tersebut tidak produktif dan ditinggalkan sebagai tambak rusak. Tambak rusak tersebut menciptakan gap area yang luas, dan dikatagorikan sebagai usikan besar, kemudian dikoloni oleh semak dan liana semak bakau. Disamping tambak udang rusak, hutan bakau Segara Anakan juga mengalami sedimentasi yang tinggi dan penebangan sisa pohon bakau. Penelitian ini mempelajari kolonisasi hutan bakau di tambak udang rusak. Pada setiap lokasi, data vegetasi dikoleksi dengan kuadrat plot 25 m x 25 m dengan ulangan 4 kali, dan juga dipelajari kualitas perairannya. Hasil mengungkapkan bahwa hutan bakau di tambak udang rusak disusun oleh dua lapisan hutan, lapisan kanopi pohon penyusun hutan dan vegetasi lantai semak dan liana bakau. Gap area yang luas sebagai usikan besar terhadap ekosistem hutan bakau, telah memicu semak dan liana semak bakau, Acanthus ilicifolius dan Derris heterophylla mengkoloni dan mendominasi lantai hutan bakau. Pohon bakaunya sangat jarang dan disusun oleh spesies seedling pohon yang ditanam dan tumbuhan alami. Pohon yang tumbuh alami adalah Sonneratia alba, Avicennia alba, dan sapling Aegiceras corniculatum berturut-turut 56-136;4; dan 4 individu per ha. Pohon yang ditanam di plataran tambak adalah Rhizophora apiculata, 4-12 individu per ha. Pohon tersebut dililit oleh liana bakau dan telah menganggu pertumbuhannya Acanthus ilicifolius dan D. heterophylla mencegah propagule pohon bakau untuk tumbuh berkembang. Semak dan liana semak bakau mendominasi dan mencirikan hutan bakau rusak, dan telah mengancam keberlanjutan ekosistem hutan bakau Segara Anakan. Kata kunci: gap kanopi, pohon bakau, Acanthus, Derris