Habitat Suitability Modeling of the Invasive Shrub Hagonoy (Chromolaena odorata (L). R.M.King & H.Rob.: Asteraceae) in the Philippines Amid Climate Change

Abstract

Chromolaena odorata (L.) R.M.King & H.Rob., a naturalized but extremely invasive shrub locally known as hagonoy, poses problems due to its allelopathic properties, which may reduce plant diversity, hinder livestock forage growth, and pose fire hazards. Despite its negative impacts, research on its growth, proliferation, and habitat preference in the Philippines, especially amid climate change, remains limited. In this study, current and future habitat suitability of C. odorata was determined through species distribution modeling. Occurrence data and environmental data, bioclimatic and remote sensing, were all obtained from well-established biogeographic databases. From these, three habitat suitability models were constructed using Maximum Entropy (MaxEnt), one under present climatic condition, another under future best-case climatic scenario, and another under future worst-case climatic scenario, all with remote sensing data. Area under the curve (AUC) score indicates that all models are acceptable. All current and future projections show that C. odorata prefers habitats with lower annual precipitation, less distinct temperature seasonality, and lower Normalized Difference Vegetation Index (NDVI). These are areas along the eastern arc of the Philippines, with concentration along the southeastern Luzon, eastern coast of Visayas, and inland southwestern Mindanao. It is recommended to add more environmental data for more robust modeling, including NDVI that are projected into the future, for more accurate predictions.