Olive Ridley Sea Turtle (Lepidochelys olivacea) Nesting Habitat Characteristics in Taman Kili-Kili Beach, Trenggalek Regency

Abstract

Taman Kili-Kili Beach in Trenggalek Regency is one of the olive ridley nesting beaches in Indonesia. Several studies have been conducted to understand its characteristics in support of sea turtle conservation management. This undergraduate study complements previous research, particularly regarding understory vegetation genera and the influence of beach characteristics on sea turtle nesting preferences. Field data collection was conducted from 2-4 May 2025 at Taman Kili-Kili Beach. Recorded data included sea turtle nests, coastal vegetation, beach slope, beach width, substrate temperature and moisture, as well as sediment grain size. A total of 13 vegetation genera were identified, with Ipomoea and Cyperus having the highest importance value index. Beach slope ranged from 1.04-5.08°, while beach width ranged from 5.5-40 m. Substrate temperature ranged from 28-35 °C and substrate moisture from 50-78%. Sediment grain size was dominated by fine sand. Eleven nests were found, mostly in the western (Station 1) and eastern parts (Station 3). According to the Canberra similarity index, both stations were more similar, particularly in terms of the values of beach width, beach slope, and the percentage of very fine sand. These factors may indicate their possible influence on sea turtle nesting behavior at Taman Kili-Kili Beach.

Pantai Taman Kili-Kili di Kabupaten Trenggalek adalah salah satu pantai peneluran penyu lekang di Indonesia. Berbagai riset telah dilakukan untuk mengetahui karakteristik pantai tersebut dengan harapan dapat membantu pengelolaan konservasi penyu sebagai spesies terancam punah. Penelitian ini hadir untuk membantu melengkapi data riset-riset sebelumnya, khususnya pada genus vegetasi tingkat bawah dan bagaimana karakteristik pantai berpengaruh pada kecenderungan penyu bertelur. Pengambilan data dilaksanakan selama 2-4 Mei 2025 di Pantai Taman Kili-Kili. Data-data yang diambil meliputi keberadaan sarang penyu, vegetasi pantai, kemiringan pantai, lebar pantai, temperatur dan kelembapan substrat, serta ukuran butir sedimen. Sebanyak 13 genus vegetasi ditemukan dengan Ipomoea dan Cyperus memiliki nilai indeks penting tertinggi. Sementara itu, kemiringan pantai berkisar antara 1.04-5.08° dengan lebar supratidal berkisar antara 5.5-40 m. Temperatur substrat berkisar antara 28-35 °C sedangkan kelembapan substrat berkisar antara 50-78%. Adapun persentase butir sedimen didominasi oleh pasir halus. Selama pengambilan data pula, ditemukan 11 sarang penyu yang cenderung berada di sisi barat (Stasiun 1) dan sisi timur (Station 3). Berdasarkan indeks similaritas Canberra, Stasiun 1 lebih mirip dengan Stasiun 3 utamanya melalui nilai lebar pantai, kemiringan pantai, dan persentase pasir sangat halus. Hal ini dapat mengindikasikan bahwa karakteristik tersebut berpengaruh terhadap perilaku bertelur penyu di Pantai Taman Kili-Kili.