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Data from: Seasonal diet partition among top predators of a small island, Iriomotejima island in the Ryukyu Archipelago, Japan

Tobe, Alisa1; Sato, Yukuto1; Wachi, Nakatada1; Nakanishi, Nozomi1; Izawa, Masako1

Research facility: University of the Ryukyus
Published Feb 20, 2024 on Dryad. https://doi.org/10.5061/dryad.x69p8czrf

Data files

Abstract

In general, small islands lack predators because species at higher trophic levels often cannot survive. However, two predators—the Iriomote cat Prionailurus bengalensis iriomotensis, and the Crested Serpent Eagle Spilornis cheela perplexus—live on Iriomotejima Island in the Ryukyu Archipelago, which covers an area of approximately 284 square kilometers. To understand how these two top predators coexist on such a small island with limited resources, we focused on their seasonal feeding habits which are considered crucial for survival in such an island ecosystem. To compare the diets of the Iriomote cat and Crested Serpent Eagle, we used DNA metabarcoding analysis of their fecal samples. In the summer, we identified 16 prey items from Iriomote cat fecal samples, and 15 Crested Serpent Eagle fecal samples. In the winter, we identified 37 and 14 prey items, respectively. Using a non-metric multidimensional scaling (NMDS) and a permutational multivariate analysis of variance (PERMANOVA), our study reveals significant differences in the diet composition at the order level between the predators during both seasons. Furthermore, although some prey items at the species-to-order level overlapped between the two predators, the frequency of occurrence of most prey items differed between them in both seasons. These results suggest that this difference in diets was one of the reasons why the Iriomote cat and the Crested Serpent Eagle coexisted on such a small island.