Nitrogen Rather Than Phosphorus Limits the Productivity of the Dominant Tree Species at Mine-Disturbed Ultramafic Areas in the Southern Philippines

Understanding the stoichiometry of nitrogen (N) and phosphorus (P) plays a pivotal role in ecological restoration degraded landscapes. Here, N P limitation dominant tree species mine-disturbed ultramafic areas Southern Philippines are reported. Field surveys revealed that out total 1491 trees/shrubs recorded from all quadrats, comprising 22 native 9 non-native species, there were six (native: Alstonia macrophylla Wallich., Buchanania arborescens Blume., Syzygium sp., non-native: Casuarina equisetifolia L., Terminalia catappa L. Acacia mangium Wild.) found dominant, having >10% relative abundance. Significant differences (p < 0.01) leaf content among these observed, where C.equisetifolia (due to fixation ability) T. had highest values, respectively. These did not, however, translate statistical N:P ratios either individual or when grouped by origin (native non-native). Interestingly, very low (<4), suggesting rather than limits productivity areas, which is also confirmed levels (<2.0%). Results further poor correlation between (r = 0.13; p 0.60), while 0.49; 0.05) otherwise, reinforcing not limiting factor as shown high (>0.20%). Despite N-limitation, B. arborescens, C. equisetifolia, content, their higher suitability for revegetation sites. findings warrant verification taking into account plant physiology, phenology, soil nutrient availability natural, degraded, rehabilitated environments.