Functional Traits of a Metal Indicator Plant, Buchanania arborescens (Blume) Blume Thriving in the Ultramafics Formation of Palawan Island: A Preliminary Assessment

The study of the plant’s functional traits may be considered an effective tool for predicting and understanding an ecosystem’s influence on plant survival. Through the direct measurement of plant responses to their immediate environment, one can understand how plants adapt to maintain their survival. The metallophytes are known for their unique capacity to thrive in metal-rich substrate, thereby offering a remarkable example of an evolutionary mechanism. However, there remains a very limited study that focuses on metallophytes, particularly focusing on their functional traits to understand their mechanisms of adaptation. Buchanania arborescens, a tree species belonging to the family Anacardiaceae, is found to thrive in multiple forest environments, including beach forests, mangroves, and tropical lowland evergreen forest, as well as the harsh environment of ultramafic forests across the Philippines. The presence of B. arborescens, therefore, raises a question on its unique ability to thrive across multiple ecosystems. In this study, the functional traits (leaf area, specific leaf area, leaf dry matter content, height, and leaf trace element) were measured from 15 randomly selected individuals collected in an ultramafic forest (Sitio Magarwak) and tropical lowland evergreen forest (Makiling Forest Reserve). Results revealed higher values for LA, SLA, and plant heights from the lowland evergreen forest, while a higher LDMC value was observed in the ultramafic area. With regard to the metals present, manganese was found in both sites, whereas nickel was only detected in the ultramafic site. The amounts of both metals, however, are not above threshold levels, suggesting that B. arborescens is a potential metal-indicator plant.