Community Structure and Health Conditions of Mangrove in Sabu Raijua

Mangrove ecosystem has an important role for the coastal ecosystem in Sabu Raijua which is included in the TNP Laut Sawu conservation area. Its designation as a water conservation area indicates that the area is an important for the protection of fishery diversity and other marine resources. Mangroves play an important role for the diversity of marine biota because of their role as a breeding ground, foraging, and nursery ground for various types of marine biota. For this reason, the role of mangrove ecosystems as supporting conservation areas is very important. The functioning of the mangrove ecosystem can be seen based on the community structure and ecosystem quality conditions. This study aims to determine the condition of the community structure and health conditions of mangroves on Sabu Raijua Island. The survey location was obtained at 5 observation stations spread across Sabu Island. The results showed that 8 species of mangrove were identified with the dominance of Mangrove Lumnitzera racemosa with an IVI value of 191%. The percentage of canopy cover found ranged from 33 – 58% with an average value of 46%. Density ranges from 23 – 45 ind/plot, with an average of 31 ind/plot. The Mangrove Health Index (MHI) value in was 36.51 ± 14.05% which is included in the Moderate category. The high value of the standard deviation (14.05) indicates that there are still mangrove locations in Sabu Raijua that have poor conditions (Poor)

Korelasi Kelimpahan Biota Bentik Pemakan Karang terhadap Kesehatan Terumbu Karang di Perairan Pulau Sabu Raijua, Nusa Tenggara Timur

ABSTRAKBiota bentik pemakan karang (Acanthaster planci, Drupella sp. dan Coralliophila sp.) merupakan predator karang yang dapat memangsa karang. Riset ini bertujuan untuk mengetahui kondisi terumbu karang, kelimpahan biota bentik pemakan karang dan bagaimana korelasi kelimpahan biota bentik pemakan karang terhadap kesehatan terumbu karang. Riset ini dilakukan pada bulan Mei – April 2021 menggunakan metode UPT (Underwater Photo Transect) untuk pengamatan terumbu karang dan metode Belt Transect untuk pengamatan kelimpahan biota bentik pemakan karang. Parameter kualitas perairan yang diukur meliputi salinitas, pH, kecerahan, kecepatan arus, nitrat dan fosfat.  Tutupan terumbu karang hidup di Perairan Pulau Sabu Raijua berkisar antara 16% - 58,72% dengan rata-rata 35,90% yang termasuk kedalam kategori “buruk – baik”. Kelimpahan biota bentik pemakan karang masih dalam batas normal yaitu Drupella sp. 0 – 0,23 ind/m2 dan Coralliophila sp. 0 – 0,07 ind/m2. Hasil analisis regresi linear menunjukan tidak terdapat korelasi antara kelimpahan biota bentik pemakan karang dan kesehatan terumbu karang di Pulau Sabu Raijua, Nusa Tenggara Timur.Kata kunci: Acanthaster planci, Coralliophila sp., Drupella sp., Kesehatan Terumbu Karang, Pulau Sabu RaijuaABSTRACTCoral-eating benthic biota (Acanthaster planci, Drupella sp. and Coralliophila sp.) are coral predators that can prey on corals. This research aims to determine the condition of coral reefs, the abundance of benthic coral-eating biota and how the correlation between the abundance of coral-eating benthic biota on the health of coral reefs. This research was conducted in May – April 2021 using the UPT (Underwater Photo Transect) method to observe coral reefs and the Belt Transect method to observe the abundance of coral-eating benthic biota. Water quality parameters measured include salinity, pH, brightness, current velocity, nitrate and phosphate. The live coral reef cover in the waters of Sabu Raijua Island ranges from 16% - 58.72% with an average of 35.90% which is included in the "bad - good" category. The abundance of coral-eating benthic biota was still within normal limits, namely Drupella sp. 0 – 0.23 ind/m2 and Coralliophila sp. 0 – 0.07 ind/m2. The results of the linear regression analysis showed that there was no correlation between the abundance of benthic coral-eating biota and the health of coral reefs on Sabu Raijua Island, East Nusa Tenggara.Keywords: Acanthaster planci, Coralliophila sp., Drupella sp., Coral Reef Health, Sabu Raijua Islan