Performa NDVI dan NDMI Landsat 8 sebagai Prediktor Spektral Kehadiran Otus jolandae di Rinjani

NDVI NDMI Landsat 8 Otus jolandae Prediktor Spektral

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Prasetyo, A. R., Gana, Y. R. S., Idris, M. H., Valentino, N., Latifah, S. ., & Wahyuni, S. (2026). Performa NDVI dan NDMI Landsat 8 sebagai Prediktor Spektral Kehadiran Otus jolandae di Rinjani. Empiricism Journal, 7(2), 1527-1537. https://doi.org/10.36312/ej.v7i2.5353

Pemetaan habitat satwa endemik di kawasan pegunungan tropis Indonesia sering terhambat oleh medan sulit dan biaya survei yang tinggi. Studi ini mengevaluasi performa Normalized Difference Vegetation Index (NDVI) dan Normalized Difference Moisture Index (NDMI) dari citra Landsat 8 OLI/TIRS tunggal resolusi 30 m sebagai prediktor spektral kehadiran Celepuk Rinjani (Otus jolandae) di Resort Timbanuh, Taman Nasional Gunung Rinjani. Citra perekaman 8 Februari 2025 dikoreksi secara atmosferik menggunakan metode Dark Object Subtraction sebelum ekstraksi indeks. Validasi melibatkan 41 titik kehadiran hasil reconnaissance survey malam selama 24 malam dan 27 titik pseudo-absence. Tiga prosedur statistik diaplikasikan: Mann-Whitney U, korelasi Pearson, dan analisis ROC. Nilai NDVI di titik kehadiran (rata-rata 0,420±0,047) berbeda signifikan dari pseudo-absence (0,323±0,059), dengan U=104, p<0,001, dan effect size r=0,683. Pola serupa muncul pada NDMI: kehadiran 0,240±0,024 versus pseudo-absence 0,196±0,037 (U=179, p<0,001, r=0,569). Korelasi Pearson NDVI–NDMI sebesar 0,412 (p<0,001) menunjukkan komplementaritas moderat-positif tanpa redundansi. Analisis ROC menghasilkan AUC NDVI 0,906 (sangat baik) dan AUC NDMI 0,838 (baik). Keduanya menunjukkan performa diskriminasi yang memadai dalam konteks area studi. Hasil ini menunjukkan bahwa NDVI dan NDMI berpotensi digunakan sebagai prediktor spektral awal untuk pemetaan habitat O. jolandae, meskipun validasi multi-musim dan multi-lokasi masih diperlukan untuk memastikan generalisasi threshold.

Performance of Landsat 8-Derived NDVI and NDMI as Spectral Predictors of Otus jolandae Occurrence in Rinjani

Abstract

Mapping the habitat of endemic wildlife in Indonesia's tropical mountain regions is frequently hampered by difficult terrain and high survey costs. This study evaluates the performance of the Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Moisture Index (NDMI) derived from a single Landsat 8 OLI/TIRS image at 30 m resolution as spectral predictors of the presence of the Rinjani Scops-Owl (Otus jolandae) in the Timbanuh Resort, Mount Rinjani National Park. An image acquired on 8 February 2025 was atmospherically corrected using the Dark Object Subtraction method prior to index extraction. Validation drew on 41 presence points recorded during reconnaissance night surveys conducted over 24 nights, and 27 pseudo-absence points. Three statistical procedures were applied: the Mann–Whitney U test, Pearson correlation, and ROC analysis. NDVI values at presence points (mean 0.420 ± 0.047) differed significantly from those at absence points (0.323 ± 0.059), with U = 104, p < 0.001, and effect size r = 0.683. A similar pattern emerged for NDMI: presence 0.240 ± 0.024 versus absence 0.196 ± 0.037 (U = 179, p < 0.001, r = 0.569). The Pearson correlation between NDVI and NDMI was 0.412 (p < 0.001), indicating moderate positive complementarity without redundancy. ROC analysis yielded an AUC of 0.906 for NDVI (excellent) and 0.838 for NDMI (good), both reflecting adequate discriminatory performance within the study area. These results suggest that NDVI and NDMI have potential as preliminary spectral predictors for mapping O. jolandae habitat, although multi-season and multi-site validation remains necessary to confirm the generalizability of the identified thresholds.