PERUBAHAN TUTUPAN HUTAN MANGROVE MENGGUNAKAN CITRA LANDSAT 5 TM dan 7 ETM DI PESISIR KABUPATEN LANGKAT

Abstract

Langkat merupakan salah satu kabupaten yang memiliki kawasan mangrove terluas di Provinsi Sumatera Utara. Sejalan dengan pertumbuhan dan perkembangan penduduk maka kebutuhan akan lahan semakin meningkat pula. Hal tersebut juga sangat berpengaruh terhadap peningkatan aktivitas konversi lahan mangrove. Berangkat dari permasalahan tersebut perlu adanya monitoring perubahan kawasan mangrove dalam 30 tahun terakhir. Metode yang digunakan dalam penelitian ini adalah pendekatan penginderaan jauh dan sistem informasi geografis untuk mengekstrak dan menganalisis informasi perubahan luasan mangrove yang terjadi selama ini 30 tahun terakhir (1989-2019). Hasil penelitian menunjukkan perubahan luasan mangrove sangat efektif dilakukan dengan menggunakan Citra Landsat 5 TM dan 7 ETM Pemisahan mangrove dengan objek non mangrove menggunakan metode klasifikasi unsupervised. Analisis kerapatan mangrove menggunakan formula NDVI dengan bantuan software Envi4.7. Hasil citra Landsat 5 TM dan citra Landsat 7 ETM+ diperoleh tingkat kerapatan mangrove sedang mendominasi distribusi hutan di pesisir pantai Kabupaten Langkat. Adapun pada rentang waktu 1989 hingga 2019 terjadi penurunan di kawasan mangrove di Langkat seluas 7.606,3234 Ha. Faktor penyebab berkurangnya kawasan mangrove di Langkat adalah konversi lahan menjadi pertanian dan perkebunan.

Structural mitigation of rob flood disaster through mangrove forest conservation in Indonesia coastal areas

“…beach [11]. Mangroves are a collection of plants that live in coastal areas located between the sea and land on the banks of rivers to estuaries that lead to the sea [12]. Mangrove ecosystems (mangroves) are ecosystems located in coastal areas that are affected by tides so that their roots are always flooded [10].…”

“…Mangroves have the structure and types of leaves and roots that are unique and different for each species, but in general have the ability to survive in muddy soil, making mangrove plants very suitable for coastal areas [12]. According to Sannigrahi et al (2019), in addition to having the function of local economic resilience, mangroves can also function as a barrier to sea waves in coastal areas that have the potential for coastal abrasion and tidal flooding [12].…”

“…The method in this study uses a qualitative descriptive approach through library research using secondary data in the form of books, laws and e-journals regarding spatial planning, especially in coastal areas by utilizing mangrove forest conservation [1,8,10,11,12,13,18,21].…”

“…According to research conducted by Murdiyarso et al, (2015) most of the deforestation of mangroves in forest areas occurs due to encroachment by communities for the development of shrimp or fish ponds [22]. Conditions of damage to mangrove forests caused by human activities in coastal areas that change mangrove forests into various other uses thus reducing the area and natural conditions such as climate change and the survival of mangroves in their habitat [12]. Meanwhile, according to Kusmana (2003) there are three main factors that cause mangrove damage, namely (a) conversion of mangrove forests that does not pay attention to environmental factors, (b) environmental pollution, and (c) excessive logging [10].…”

“…With the reduction of mangrove areas that can withstand tidal waves in coastal areas, the potential for disasters will be even greater with more frequent occurrences and a reduced ability to erode land in coastal areas, break waves, withstand strong winds so that coastal areas become submerged in tidal flooding [12]. Several tidal floods and coastal abrasion occurred in various parts of Indonesia, such as Leuge Village, Aceh [8], Tanggul Tlare Village, Jepara [10], Ketapang Raya Village, East Lombok [11], Langkat Regency, North Sumatra [12] and the City of Pariaman, West Sumatra [13].…”