Tree biodiversity in Bornean lowland forest: What are the key species for forest city development in the new capital city of Indonesia?

PLOS ONE | https://doi.org/10.1371/journal.pone.0320489 April 8, 2025 1 / 19 OPEN ACCESS Citation: Atmoko T, Sitepu BS, Adinugroho WC, Mukhlisi, Sayektiningsih T, Setyawati T, et al. (2025) Tree biodiversity in Bornean lowland forest: What are the key species for forest city development in the new capital city of Indonesia?. PLoS ONE 20(4): e0320489. https://doi.org/10.1371/journal.pone.0320489 Editor: Gandhiv Kafle, Agriculture and Forestry University, Nepal Received: May 5, 2023 Accepted: February 17, 2025 Published: April 8, 2025 Copyright: © 2025 Atmoko et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data availability statement: All relevant data on tree species characteristics are within the paper and its Supporting Information files. Funding: The authors received no specific funding for this work. Competing interests: The authors have declared that no competing interests exist. RESEARCH ARTICLE Tree biodiversity in Bornean lowland forest: What are the key species for forest city development in the new capital city of Indonesia? Tri Atmoko1☯, Bina Swasta Sitepu 2☯, Wahyu Catur Adinugroho 2☯, Mukhlisi1☯, Tri Sayektiningsih3☯, Titiek Setyawati2☯, Francis Q. Brearley 4☯*, Ishak Yassir5☯ 1 Research Center for Applied Zoology, Research Organization for Life Sciences and Environment, National Research and Innovation Agency (BRIN), Bogor, Indonesia, 2 Research Center for Ecology

and Ethnobiology, Research Organization for Life Sciences and Environment, National Research and Innovation Agency (BRIN), Jakarta, Indonesia, 3 Makassar Environment and Forestry Standard Instrument Implementation Institute, Ministry of Environment and Forestry (BPSILHK Makassar), Makassar, Indonesia, 4 Department of Natural Sciences, Manchester Metropolitan University, Manchester, United Kingdom, 5 Samboja Environment and Forestry Standard Instrument Implementation Institute, Ministry of Environment and Forestry (BPSILHK Samboja), Samboja, Indonesia ☯ These authors contributed equally to this work. * f.q.brearley@mmu.ac.uk Abstract The national capital of Indonesia is in the early stages of relocation from the island of Java to East Kalimantan; Indonesia’s new capital city (Ibu Kota Negara; IKN) will be called Nusantara. The development of IKN will utilise the concept of a forest city representing the lowland forest of Borneo containing its rich biodiversity. To realize this concept, sufficient data and information regarding the status of tree diversity in this area is required. To provide this information, research was conducted in sample plots totaling 20.75 ha spread over eight locations in East Kalimantan. The selection of priority tree species for reha- bilitation was carried out by using the Analytical Hierarchy Process (AHP) method with the criteria of conservation status, endemicity, climax species, distribution, food poten- tial, ethnobotanical potential, animal food, and tree growth rates. In the sample plots, we

found 5,745 trees representing 571 species with the family Dipterocarpaceae dominating, followed by Euphorbiaceae, Phyllanthaceae, Malvaceae and Annonaceae. Based on the priority categories of restoration, most of the species proposed for planting belong to the Dipterocarpaceae, in the genera Anisoptera (2 species), Anthoshorea (2 species), Cotyle- lobium (1 species), Dipterocarpus (3 species), Dryobalanops (1 species), Hopea (3 species), Richetia (3 species), Rubroshorea (7 species), Shorea (4 species), and Vat- ica (4 species). Hopea rudiformis is a Critically Endangered and Borneo endemic species with the highest score, and the only species included in 1st priority, followed by 14 species in 2nd priority, 62 species in 3rd priority, and the remainder in 4th priority. About 18% of tree species with potential food sources can be planted to meet the 10% target of forest cover to contribute to food security in IKN. Samboja Research Forest, Sungai Wain Protection