Plant Diversity and Vegetation Characteristics of the Forest over Limestone Mining Site in Tubay, Agusan del Norte, Philippines

Abstract

Mining in areas with high diversity and endemism pose serious and highly specific threats to biodiversity. The study aims to assess the plant diversity, community structure, and vegetation characteristics of the limestone forest mining site in Tubay, Agusan del Norte, Philippines. The limestone mining project is covered by the Mineral Production Sharing Agreement (MPSA) of Agata Mining Ventures Incorporated (AMVI). A field survey was carried out in twelve (12) 20 m x 20 m nested plots established in the two sampling sites; Site 1 (Payong-payong) and Site 2 (Tinigbasan). Payong-payong can be categorized as a forest over limestone while Tinigbasan is an agricultural, planted forest. Results revealed 206 plant species belonging to 78 families and 145 genera. Of these, fourteen were identified as threatened species. When plants are grouped into plant habit, results revealed that trees and shrubs had the highest number of species among the group. Vitex parviflora (tugas) and Artocarpus blancoi (Antipolo) obtained the highest species importance value (SIV) in sites 1 and 2, respectively, indicating that the two are the most influential and important species. Both areas showed a high diversity of plants with a composite Shannon diversity of 3.97. Multivariate analysis showed significant variation in plant community structure (Anosim R=0.7, p<0.001), which suggests differences and uniqueness of plant species composition between the two sampling sites. The differences in species diversity and community structure of plants can be attributed to the variety of forest habitat types and physical attributes found in the two areas. Our data provide valuable information in creating pragmatic and effective conservation and management strategies for the sustainable use of resources while preserving the ecological integrity and biodiversity as mining progresses in the limestone forest.