Keberadaan Buaya (Crocodylus spp.) di Sungai Kao, Kabupaten Boven Digoel, Provinsi Papua Selatan

Abstract

Sungai Kao di Kabupaten Boven Digoel, Papua Selatan, merupakan habitat strategis bagi buaya (Crocodylus spp.), namun data populasinya masih terbatas. Penelitian ini bertujuan untuk pemetaan buaya di sekitar Sungai Kao, menduga jumlah populasi, dan mendeskripsikan kondisi umum habitat. Pengambilan data menggunakan metode spotlight survey. Sebanyak 106 individu teramati di seluruh transek yang didominasi oleh buaya sahul (Crocodylus halli). Rata-rata kelimpahan relatif adalah 0,62 ind/km. Berdasarkan analisis N-mixture model, model null mengestimasi total populasi sebesar 112,40 individu dengan probabilitas deteksi (p) 0,2827, sedangkan model suhu air mengestimasi 143,60 individu (p= 0,2011–0,2437). Hasil ini menunjukkan bahwa metode hitung langsung cenderung menghasilkan estimasi yang lebih rendah (underestimate) dari populasi sebenarnya akibat deteksi yang tidak sempurna (imperfect detection). Karakteristik habitat berupa vegetasi riparian yang rapat (didominasi semak dan ilalang) dapat menurunkan probabilitas deteksi visual.

Kao River in Boven Digoel Regency, South Papua, serves as a strategic habitat for crocodiles (Crocodylus spp.), yet population data remains limited. This study aimed to map the crocodile distribution around the Kao River, estimate the population size, and describe the general habitat conditions. Data collection was conducted using the spotlight survey method. A total of 106 individuals were observed across all transects, which were dominated by the Hall’s New Guinea crocodile (Crocodylus halli). The average relative abundance was 0,62 ind/km. Based on the N-mixture model analysis, the null model estimated the total population at 112,40 individuals with a detection probability (p) of 0,2827, whereas the water temperature model estimated 143,60 individuals (p= 0,2011–0,2437). These results indicate that direct count methods tend to underestimate the actual population due to imperfect detection. Habitat characteristics featuring dense riparian vegetation (dominated by shrubs and thatch grass) can decrease visual detection probability.