Tesis a.n Zulfandra Bachrul Kalam (C5501241023)

Abstract

Peristiwa pemutihan karang global keempat yang dikonfirmasi NOAA pada April 2024 terjadi bahkan sebelum puncak El-Niño, mengindikasikan bahwa pemanasan antropogenik kini menjadi faktor dominan di balik anomali termal lautan tropis. Kepulauan Seribu, yang berada pada lintang rendah dengan frekuensi pemutihan tertinggi secara global, menghadapi tekanan ganda berupa degradasi lokal dan stres termal regional. Penelitian ini bertujuan menganalisis kondisi tutupan karang keras dan tingkat pemutihan karang di area perlindungan laut di Gosong Pramuka (APL) dan area rehabilitasi yang dikelola Smiling Coral Indonesia (ARS) di selatan Pulau Pramuka. Penelitian dilaksanakan pada Januari 2024 di dua area terumbu karang di sekitar Pulau Pramuka, Kepulauan Seribu, pada tiga kedalaman (5 m, 10 m, dan 15 m). Data foto dikumpulkan dari transek kuadran berukuran 1 m ×1 m dengan modifikasi metode dari Yvone et al. 2016. Identifikasi lifeform dan genus karang menggunakan Coral Finder 2021 kemudian estimasi tutupan menggunakan perangkat lunak CPCe V4.1. Analisis data meliputi uji Mann-Whitney U, uji Kruskal-Wallis, dan korelasi Spearman pada taraf signifikan a = 0,05. Kondisi terumbu karang di APL tergolong buruk pada semua kedalaman (dengan rerata HCAPL= 12,88±7,77%) dengan dominasi tutupan substrat oleh DC (karang mati), DCA (dead coral with algae), dan rubble (pecahan karang), sedangkan di ARS mencatatkan tutupan HC (karang keras) lebih tinggi (HCARS= 38,32±25,53%) dan berbeda signifikan (U= 9,00; p= 0,006) karena dibantu oleh tutupan karang hasil transplantasi yang aktif dikelola Smiling Coral Indonesia, dengan perbedaan antar lokasi terbukti signifikan (UHC= 9,0; p = 0,006). Pemutihan karang di area perlindungan (BlAPL= 81,33%) teramati lebih parah dibandingkan area rehabilitasi (BlARS= 25,96%) dan menunjukkan perbedaan signifikan (UCBl= 81,0; p = 0,0004) meskipun suhu perairan antar lokasi menunjukkan nilai yang seragam (~30 °C). Tidak ada perbedaan signifikan dari kejadian pemutihan karang antar kedalaman (p > 0,05), namun ada korelasi negatif yang kuat antara tutupan karang keras dan karang yang memutih (rs= -0,681; p= 0,002), sehingga kondisi lingkungan lokal menentukan besar-kecilnya dampak pemutihan terhadap ekosistem terumbu karang. Dijumpai 7 dan 9 lifeform karang keras di APL dan ARS, dengan tipe dominan CF (Coral Foliose), CMR (Coral Mushroom) dan CM (Coral Massive) sedangkan di ARS didominasi oleh CB (Coral Branching). Keragaman genera karang keras di APL sangat tinggi dengan dijumpainya 21-28 genus namun yang memiliki kondisi sehat hanya 6-10%. Di area rehabilitasi SCI (ARS) keragaman jenis karang hanya 18 genus di kedalaman 10 meter, sedangkan di 15 meter dan 5 meter ada 11 dan 6 genus saja dengan kondisi sehat mencapai 48-59%. Semua lifeform karang keras di APL rentan karena pemutihannya tinggi (73-83%), sedangkan di ARS hanya 22-33%. Genus karang keras yang dominan di APL adalah Pachyseris dan Pleuractis, sementara di ARS didominasi Porites. Keragaman genus karang yang lebih tinggi di APL (21–28 genera) tidak serta merta mencerminkan kondisi terumbu karang yang lebih baik dibandingkan area rehabilitasi, karena persentase pemutihannya sangat tinggi. Temuan ini menunjukkan bahwa Area Rehabilitasi Smiling Coral mengalami dampak pemutihan yang lebih rendah dibandingkan area perlindungan laut pada peristiwa pemutihan 2024, meskipun terpapar suhu yanf serupa. Terumbu karang di Area Rehabilitasi menunjukkan indikasi ketahanan terhadap pemutihan yang lebih baik dibandingkan APL pada saat pengamatan. Integrasi program rehabilitasi aktif dalam pengelolaan area perlindungan merupakan langkah mendesak untuk membangun ketahanan ekosistem terumbu karang di Pulau Pramuka dan Kepulauan Seribu.

The fourth global coral bleaching event confirmed by NOAA in April 2024 occurred even before the peak of El-Niño, indicating that anthropogenic warming has become the dominant driver of thermal anomalies in tropical oceans. The Thousand Islands Archipelago, situated at low latitudes where bleaching frequency is among the highest globally, faces a dual pressure of local degradation and regional thermal stress. This study aimed to analyze hard coral cover conditions and coral bleaching prevalence at the marine protected area in Gosong Pramuka (MPA) and the rehabilitation area managed by Smiling Coral Indonesia (ARS) in the southern part of Pramuka Island. The study was conducted in January 2024 at two reef areas around Pramuka Island, Thousand Islands, at three depths (5 m, 10 m, and 15 m). Photo data were collected from 1 m × 1 m quadrat transects using a modified method from Yvone et al. 2016. Lifeform and coral genus identification used Coral Finder 2021, and cover estimation was performed using CPCe V4.1 software. Data analyses included the Mann-Whitney U test, Kruskal-Wallis test, and Spearman rank correlation at a significance level of a = 0.05. Reef conditions at the MPA were classified as poor across all depths (mean HCAPL = 12.88 ± 7.77%) with substrate dominated by DC (dead coral), DCA (dead coral with algae), and rubble, while the ARS recorded higher hard coral cover (HCARS = 38.32 ± 25.53%) assisted by transplanted coral cover actively managed by Smiling Coral Indonesia, with the difference between sites statistically significant (UHC= 9.0; p = 0.006). Coral bleaching at the protected area (BlAPL = 81.33%) was observed to be more severe than at the rehabilitation area (BlARS= 25.96%), showing a significant difference (UCBl~ = 81.0; p = 0.0004) despite uniform water temperatures between sites (~30°C). No significant difference in coral bleaching was found among depth strata (p > 0.05), yet a strong negative correlation was found between hard coral cover and bleaching prevalence (rs = -0.681; p = 0.002), indicating that local environmental conditions determine the magnitude of bleaching impacts on coral reef ecosystems. Seven and nine hard coral lifeforms were recorded at the APL and ARS respectively, with dominant types being CF (Coral Foliose), CMR (Coral Mushroom), and CM (Coral Massive) at the MPA, while the ARS was dominated by CB (Coral Branching). Hard coral genus diversity at the APL was very high with 21–28 genera recorded, yet only 6–10% were in healthy condition. At the SCI rehabilitation area (ARS), genus diversity reached only 18 genera at 10 m depth, while at 15 m and 5 m there were 11 and 6 genera respectively, with healthy condition reaching 48–59%. All hard coral lifeforms at the ARS were vulnerable due to high bleaching prevalence (73–83%), while at the ARS it was only 22–33%. The dominant hard coral genera at the APL were Pachyseris and Pleuractis, while the ARS was dominated by Porites. Higher genus diversity at the APL (21–28 genera) did not necessarily reflect better reef condition compared to the rehabilitation area, as bleaching prevalence was very high. These findings confirm that the coral rehabilitation area managed by Smiling Coral Indonesia experienced substantially lower bleaching impact than the marine protected area during the 2024 bleaching event, despite similar thermal exposure." "The coral reefs in the SCI rehabilitation area showed better indication of bleaching resistance at the time of observation. Integration of active rehabilitation programs into protected area management is an urgent step toward building coral reef ecosystem resilience on Pramuka Island and throughout the Thousand Islands Archipelago.