Agroforestry within a Limestone Forest in Tuba, Benguet, the Philippines, Conserved and Managed through Public-Private Partnership Reveals High Species Richness and Diversity

Understanding the composition, diversity, ecological classification, and conservation status of plant species is crucial for effective biodiversity conservation. However, existing studies in Benguet, the Philippines, primarily focus on communal forests, forest reservations, and national parks characterized by pine and mossy forests. There is a notable gap in research within other biodiversity-rich forest formations in the province. To address this, this paper investigated plant species composition and biodiversity dynamics in the Nangalisan Agroforest Sanctuary (NAS) – a 43-ha forest over limestone in Tuba, Benguet, managed and conserved through public-private partnerships. The findings identified 118 species across 95 genera and 54 families, showcasing a high floral diversity with a Shannon-Weiner diversity index (H’) of 4.42, and a Margalef species richness index (R) of 117.84, which is higher compared with similar ecosystems in other parts of the country. Based on the IUCN categories, three threatened and one near-threatened plant species were identified. Additionally, six species from the National List of Threatened Species (DAO 2017-11) were also identified as priorities for conservation. Of the documented samples, 69% were native, 11% endemic, and 20% exotic – including six (6) alien invasive plant species, which are very detrimental to the ecological health of the agroforestry sanctuary. This study enhances the understanding of plant diversity dynamics in agroforestry areas in Benguet while also highlighting the crucial role of public-private partnerships in conservation.