Population Assessment,Updated Description,and Prediction of Habitat Distribution for the Sumatran Endemic Tree Magnolia calophylloides (Magnoliaceae)

Abstract

Background and Background Aim: Magnolia calophylloides Figlar & Noot. is a narrowly endemic Indonesian species, currently listed as Data Deficient on the IUCN Red List. Originally described from Mount Kerinci in 1914, it was last recorded in the wild in 1972. This study aimed to update knowledge on its distribution, population size and structure, habitat preferences, threats, and conservation status. Methods: Field surveys were conducted at historical sites on Mount Kerinci and Mount Tujuh, and a previously unsurveyed area, Ladeh Panjang, in Jambi Province. We assessed population metrics, habitat characteristics, and threats, and updated the species’ taxonomic description based on live observations. Species distribution modeling was used to predict potential habitat suitability. Results: A total of 389 individuals were recorded across the three sites, with 316 (81%) mature. Flowering and fruiting individuals enabled the first photographic documentation of fresh flowers and revision of its morphological description. The primary threats observed were logging and forest conversion to agriculture. Based on population size, extent of occurrence (97.79 km²), and area of occupancy (32 km²), we recommend reclassifying M. calophylloides as Endangered under IUCN criteria B1ab+B2ab(i,ii,iii,v); C2a(i). Conclusions: M. calophylloides is confirmed as a montane forest specialist with a highly restricted elevational range (1,861–2,322 m) and very limited distribution in Sumatra. Its small population and continued habitat loss highlight the species’ vulnerability. Implications for Conservation: Targeted conservation is urgently needed. Priorities include habitat protection, enforcement against illegal logging, community-based forest management, and surveys in nearby suitable areas such as Mount Masurai. The species’ unique traits and evolutionary significance also make it a strong candidate for further research and a flagship for montane forest conservation in Sumatra.