Agung Hasan Lukman, Alnus Meinata, Agus Susatya, Firman Hadi, Karyadi Baskoro, Fatchur Rohman, Indra Fardhani, Arief Hamidi, Hardi Wardoyo, Eko Sudaryanto, Takuto Shitara, Takashi Kamijo, Tetsuya Matsui
Field surveys for rare and endangered species are essential to identify new populations and improve the understanding of their natural distribution for effective conservation but are often constrained by limited prior information. In the present study, the fieldwork guided by species distribution models (SDMs) and local ecological knowledge (LEK) was conducted to discover previously unknown distributions of endangered Castanopsis argentea and C. tungurrut on Java, Indonesia. We performed field surveys at six locations in central and east Java and one in west Java. As a result, we discovered 723 individuals of C. argentea, elevations between 756 m and 2,021 m, at 34 sites in six locations. C. argentea populations persisted across varied dry-season precipitation regimes but declined sharply eastward, with no records from Mt. Ijen. Morphological variation, including a novel trait of pseudo-whirled twiglets, was also observed, potentially indicating local adaptation and intraspecific differentiation. In contrast, C. tungurrut was only found at three sites in west Java, in association with three individuals. These findings demonstrate the value of integrating SDMs and LEK to locate overlooked populations and generate ecological insights that can guide conservation measures, including enhancing species distribution databases, habitat protection, and restoration planning to support long-term endangered species persistence. © 2026 Elsevier GmbH
of Science and Technology, University of Tsukuba, 1-1-1 Tennodai, Ibaraki, Tsukuba, 305-8572, Japan; Department of Forestry, Faculty of Agriculture, Universitas Bengkulu, Kandang Limun, Bengkulu, 38371, Indonesia; Faculty of Forestry, Universitas Gadjah Mada, Jl. Agro No. 1, Bulaksumur, Yogyakarta, Sleman, 55281, Indonesia; Universitas Diponegoro. Jl. H. Prof. Soedarto, SH., Tembalang, Central Java, Semarang, 50275, Indonesia; Universitas Negeri Malang. Jl., Semarang 5, East Java, Malang, 65145, Indonesia; Indonesia Forum for Threatened Trees (FPLI), Kusnoto Building, Jl. Ir. H. Juanda 18 Bogor 16122, West Java, Indonesia; Perhutani Forestry Institute, Perum Perhutani, Jl. Rimba Mulya No. 11 Kartoharjo, Kota Madiun, Indonesia; Tama Forest Science Garden, Forestry and Forest Products Research Institute (FFPRI), 1833-81 Todorimachi, Tokyo, Hachioji, 193-0843, Japan; Institute of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Ibaraki, Tsukuba, 305-8572, Japan; Department of Forest Vegetation, Forestry and Forest Products Research Institute (FFPRI), Matsunosato 1, Ibaraki, Tsukuba, 305-8687, Japan
