Forests 2021, 12, 1449. https://doi.org/10.3390/f12111449 www.mdpi.com/journal/forests Article Predicting the Habitat Suitability of Melaleuca cajuputi Based on the MaxEnt Species Distribution Model Nor Zafirah Ab Lah 1, *, Zulkifli Yusop 1 , Mazlan Hashim 2 , Jamilah Mohd Salim 3 and Shinya Numata 4 1 Centre for Environmental Sustainability and Water Security (IPASA), Universiti Teknologi Malaysia, Johor Bahru 81310, Johor, Malaysia; zulyusop@utm.my 2 Research Institute for Sustainable Environment (RISE), Universiti Teknologi Malaysia, Johor Bahru 81310, Johor, Malaysia; mazlanhashim@utm.my 3 Institute of Tropical Biodiversity & Sustainable Development (BIO-D TROPIKA), Universiti Malaysia Terengganu, Kuala Nerus 21030, Terengganu, Malaysia; jamilah@umt.edu.my 4 Department of Tourism Science, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, Tokyo 192-0397, Japan; nmt@tmu.ac.jp * Correspondence: nzafirah7@graduate.utm.my Abstract: Gelam tree or Melaleuca cajuputi (M. cajuputi) is an important species for the local economy as well as coastal ecosystem protection in Terengganu, Malaysia. This study aimed at producing a current habitat suitability map and predicting future potential habitat distribution for M. cajuputi in Terengganu based on Species distribution modeling (SDM) using the Maximum Entropy principle. Our modeling results show that for the current potential distribution of M. cajuputi species, only 10.82% (1346.5 km 2 ) of Terengganu area is suitable habitat, which 0.96% of the areas are under high, 2.44% moderate and 7.42% poor habitat suitability. The model prediction for future projection shows that the habitat suitability for M. cajuputi would decrease significantly in the year 2050 under RCP 4.5 where the largest contraction from suitable to unsuitable habitat area is about 442.1 km 2 and under RCP 2.6 is the highest expansion from unsuitable to suitable habitat area (267.5 km 2 ). From the future habitat suitability projection, we found that the habitat suitability in Marang would degrade significantly under all climate scenarios, while in Setiu the habitat suitability for M. cajuputi remains stable throughout the climate change scenarios. The modeling prediction shows a signifi- cant influence on the soil properties, temperature, and precipitation during monsoon months. These results could benefit conservationist and policymakers for decision making. The present model could also give a perception into potential habitat suitability of M. cajuputi in the future and to im- prove our understanding of the species’ response under the changing climate. Keywords: Melaleuca cajuputi; Maxent; species distribution; habitat suitability; climate change; soil properties 1. Introduction Global warming has caused significant changes in spatial and temporal environmen- tal patterns, and these changes also affect effort to conserve biodiversity [1]. In tropical climates, changes in temperature and precipitation can affect species habitat and plant phenology, both directly and indirectly [2]. Climate change effect also threatened Mela- leuca swamp forest where the sea level rise causes saltwater intrusion and indirectly af- fects the Melaleuca swamp forest because of an increase in salinity [3]. Melaleuca genus is from the family of Myrtaceae that comprises 260 species, naturally distributed in Aus- tralia, Indonesia, Malaysia, Singapore, Thailand and Vietnam [4]. Melaleuca forests grow in coastal regions such as wetlands, lowlands, and peat lands, often behind the mangrove zone where pure or mixed stands may form. In Peninsular Malaysia, Melaleuca cajuputi (M. cajuputi) or known as white-paperbark tree (kayu putih) or Gelam, is the native species Citation: Ab Lah, N.Z.; Yusop, Z.; Hashim, M.; M.Salim, J.; Numata, S. Predicting the Habitat Suitability of Melaleuca cajuputi Based on the MaxEnt Species Distribution Model. Forests 2021, 12, 1449. https://doi.org/10.3390/f12111449 Received: 26 July 2021 Accepted: 20 October 2021 Published: 24 October 2021 Publisher’s Note: MDPI stays neu- tral with regard to jurisdictional claims in published maps and institu- tional affiliations. Copyright: © 2021 by the authors. Li- censee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and con- ditions of the Creative Commons At- tribution (CC BY) license (https://cre- ativecommons.org/licenses/by/4.0/).