Philippine Journal of Science 148 (2): 359-371, June 2019 ISSN 0031 - 7683 Date Received: 13 Dec 2018 Native Trees on Mount Lantoy Key Biodiversity Areas (KBA), Argao, Cebu, Philippines Edgardo P. Lillo1,3*, Archiebald B. Malaki1, Steve Michael T. Alcazar1, Ritchie U. Nuevo1, and Raamah Rosales2 1Cebu Technological University – Argao Campus, Argao 6021 Cebu, Philippines 2Cebu Technological University – Main Campus, Cebu City 6000 Cebu, Philippines 3Forest Biological Sciences, College of Forestry and Natural Resources, University of the Philippines Los Baños, College 4031 Laguna, Philippines The forest cover of Cebu Island was now less than 1% of its total land area. The almost complete deforestation of Cebu Island has apparently led to the extinction of many native trees, birds, and other wildlife. Assessing native trees on Mount Lantoy key biodiversity areas (KBA) was important in providing materials to support the human decision-making process in the management of the area. Permanent plots with 20 m x 100 m dimension were established both in lower and upper elevations of Mount Lantoy KBA. A total of four plots were established in highly stratified vegetation to generate information in all vegetation classes. A total of 112 species, classified into 64 families and 84 genera, were recorded. Out of 112 species, 88 were native trees, 10 shrubs, three ferns, three herbs, four vines, and four epiphytes. Majority of the species were recorded in Plots 1, 2, and 4. Seventeen native trees were categorized as threatened – with two species considered as critically endangered, three endangered, nine vulnerable, and three other threatened species identified. Mount Lantoy KBA has high species diversity (‘H = 3.5”), dominated by the species of Parishia malabog Merr. (15.287%) in terms of diameter, richness, and density per hectare. Majority of the native trees have a diameter of 10–19 cm (66%) and basal area of 8 m2/ha. Native trees of Mount Lantoy were threatened by illegal cutting, hunting, and the rampant conversion of forests to agriculture, with disturbance index value of moderately disturbed. All this information on native trees were essential for decision making, particularly in the rehabilitation and conservation of Mount Lantoy KBA. Keywords: Argao, Cebu Island, key biodiversity areas (KBA), Mount Lantoy, native trees INTRODUCTION the Manila-Acapulco trade route during the seventeenth and eighteenth centuries. American colonialists further The island of Cebu is located in Central Visayas and developed forest extraction and engaged in the wanton considered as the most denuded island in the central exportation of logs to their home country (Asia Magazine Philippines (Collar et al. 1999). Rapid depletion of 1984). Bensel (2008) reiterated further that expansion of Philippine forest resources began during the Spanish agriculture and fuel wood gathering is still increasing and colonial period. During this period, the island of Cebu creating pressure on the last remaining forests on Cebu. was completely stripped of its large hardwood trees to provide lumber for building Spanish galleons plying The forest cover of Cebu Island is now less than 1% of its total land area (Mallari et al. 2001). Several forest *Corresponding author: [email protected] species recorded in the late 1950s are now considered 359 Philippine Journal of Science Lillo et al.: Native Trees on Mt. Lantoy Vol. 148 No. 2, June 2019 Key Biodiversity Areas locally extinct (Rabor 1959, Magsalay et al. 1995, Brooks the diversity and structure of the native tree species in et al.1995, Collar et al.1999). The almost complete KBA are essential in providing information on species deforestation of Cebu Island has apparently led to the richness and for forest management purposes, as well as in extinction of many native trees, birds, and other wildlife understanding forest ecology and ecosystem functioning (Brooks et al. 1995). Bird Life International identified (Giriraj et al. 2008, Pappoe et al. 2010). Sustainable use Cebu as an important bird area. It is one of the world’s and management of natural resource is intimately linked most critical endemic bird areas in terms of both numbers to ecology, as each management system interferes with the of threatened endemic species and degrees of threat forest structures and processes (Schmidt 1982). (Dickinson et al. 1991, Stattersfield et al. 1998). The study aimed to assess the native trees in Mount Mount Lantoy is among the 117 terrestrial areas Lantoy KBA for protection and biodiversity conservation. designated as KBA based on criteria of vulnerability and Specifically, the study aimed to describe the physical irreplaceability, and is part of the 85 new sites (Mount description of the sites, composition, conservation status, Lantoy and Nug-as KBA) with a total area of 10,457 phenology, clustering analysis, disturbance, and threat. hectares. These sites have two critically endangered, two endangered, four vulnerable, and 16 restricted- range species (CI/DENR-PAWB/Haribon 2006). Pelser and Barcelona (2017) recorded the critically METHODOLOGY endangered Cynometra cebuensis species in Mount Lantoy KBA. Native trees constitute the basic foundation Study Area of the country’s forest ecosystems. Countless centuries The study was conducted in Argao (Mount Lantoy) Forest of evolution through natural selection has given native (9°549 N, 123°329 E) at 100–800 m elevation (Figure 1). trees adaptability to their respective local environments Mount Lantoy is part of the Argao-Dalaguete Watershed (Lantican 2015). Forest Reserve declared by a Presidential Proclamation 2 Information on the diversity and structure of native trees (No. 414, 29 Jun 1994). Its peak has an area of 0.5 km in any of the KBA of the southern part of Cebu Island is and is surrounded by cultivation, coconut plantations, and still inadequate and nowhere found in any of the published plantations of non-indigenous trees and scrubland, which literature in a scientific journal. Evaluating and updating were also used by local communities for grazing their Figure 1. Cebu Island in the Philippine map, the study site (Mount Lantoy) in the map of Cebu, and plot locations (GIS generated map; Landsat 8; www.earthexplorer.usgs.ph; NAMRIA; Philippine GIS data). 360 Philippine Journal of Science Lillo et al.: Native Trees on Mt. Lantoy Vol. 148 No. 2, June 2019 Key Biodiversity Areas livestock. Seasonal crops like cabbage, corn, onion, and other plants below 1 m in height) was accounted for inside carrot were planted in agricultural farms surrounding the the 1 m x 1 m quadrat for all the plots. forests (Paguntalan and Jakosalem 2008). Plant Species Identification and Conservation Status Establishment of Sampling Plots Voucher specimens for every individual of plants within Permanent plots were established in lower (less than 200 the plots were collected and tagged. The collected m) and upper elevation (above 500 m) areas of Mount specimens were brought to the herbarium laboratory Lantoy. The size of the plots was 20 m x 100m, and a of Cebu Technological University – Argao Campus for total of four plots were established in highly stratified proper identification after oven-drying. Identification vegetation to generate information in all vegetation of sample specimens were done through manual means classes (Figure 2). A vegetation class is usually composed (Checklist of Species in Mount Makiling; Fernando of different strata or layers such as tree canopies, shrub 2007), herbarium comparison (Philippine National canopies, grass cover, and litter (Wang et al. 2001, Wu Museum file), digital database (Co’s Digital Flora of the and Zhao 2001, Zhang et al. 2006). Coordinates of all the Philippines; https://www.philippineplants.org), online established permanent plots were taken and recorded. The literature (http://www.theplantlist.org), and the expertise number of established permanent plots depends upon on of Dr. Edwino S. Fernando and Dr. Pastor Malabrigo the availability of stratified vegetation cover, as well as (plant taxonomist; CFNR, UPLB, Laguna, Philippines) as on the accessibility of the site. project consultants. Conservation status of the species was determined based on classifications by the Department of Environment and Natural Resources (DENR 2017) and the International Union for the Conservation of Nature (IUCN 2017). The identified herbarium specimens were deposited in the newly established mini-museum of the institution. The mini-museum showcased the different species collected from Mount Lantoy KBA for instruction and research purposes. Measurement of Trees The data for forest structure includes DBH, TH, crown diameter, and basal area. Native trees with diameters of 10 cm and above were measured. The measurement of DBH was done with the use of diameter tape for larger trees and tree caliper for smaller trees. For the total height of the trees, the measurement was made by the use of Abney hand level. For the crown height and width, their measurements were done through estimation. TH and DBH were categorized into different classes, namely: 10–19 cm, 20–29 cm, 30–39 cm, and 40 cm and above (Lulekal et al. 2008). Basal area was calculated by using Figure 2. Location of sampling plots in the study site (GIS generated the formula BA = 0.7854 (d)2, where d is the DBH in meter map; Landsat 8; www.earthexplorer.usgs.ph; NAMRIA; (DENR 1993). Plant density was a count of the numbers of Philippine GIS data). individuals of species within the quadrant and computed on hectare basis. Documentation of the vegetative and reproductive structures of native trees were done with Nested quadrat sampling technique was used to assess and high resolution camera. The phenology also of the native characterize the structure and species composition of the trees inside the plot were recorded. Species and family different plant communities. For large woody plants whose names followed the latest Angiosperm Phylogeny Group diameter equal or greater than 10 cm, measurements of classification (APG 2016). diameter at breast height (DBH), merchantable height (MH), and total height (TH) were done inside the 20 m x Mapping of Native Tree Species 100 m quadrat.