Philippine Journal of Science 150 (S1): 271-280, Special Issue on Biodiversity ISSN 0031 - 7683 Date Received: 05 Oct 2020 Vegetation Analysis of Sanctuary and Forest Areas of Kalahan Forest Reserve Nueva Vizcaya and Pangasinan, Philippines Florencia B. Pulhin1*, Alfie M. Torres2, Nelson M. Pampolina3, Rodel D. Lasco5, and Angela Marie Alducente4 1Forestry Development Center; 2Department of Forest Products and Paper Science 3Department of Forest Biological Sciences; 4Institute of Renewable Natural Resources College of Forestry and Natural Resources, University of the Philippines Los Baños College, Laguna, Philippines 5World Agroforestry Center, College, Laguna, Philippines Many areas in the country are rich in biodiversity but are not assessed as they are not part of the identified protected areas of the country. One of which is the Kalahan Forest Reserve (KFR) managed by the Ikalahans, a cultural minority group that practices sustainable agroforestry systems. The study used a modified quadrat sampling method (QSM) where a total of eight 1-km transect with 20-m width were established to assess the biodiversity of the area. The sampling was undertaken in three layers: overstorey (10 plots each measuring 10 m x 10 m, spaced 100 m away from each other in each 1-km transect), intermediate (3 m x 3 m inside the 10 m x 10 m plot), and understorey (1 m x 1 m inside the 3 m x 3 m plot). Results of the study show that Benguet pine (Pinus insularis Endl) and brown oak (Quercus semecarpifolia Sm.) have high importance values of 49.07 and 45.80, respectively. Moreover, the results of the study indicate that KFR has very high biological diversity as manifested by the value of Shannon-Weiner (3.50) and the Shannon diversity index scale of Fernando. In terms of the presence of endemic species, KFR is home to 50 endemic species or has 45% endemism. Based on the International Union for the Conservation of Nature (IUCN) Red List and DAO 2017-11 KFR has three threatened, two endangered, and three vulnerable species. Considering these results, KFR is worthy to be protected to conserve and enhance its biodiversity. Keywords: biodiversity, conservation value, endemic, Kalahan Forest Reserve INTRODUCTION (BMB-DENR 2016, as cited by Ani and Castillo 2020). Almost half of these floral and faunal species can only be The Philippines is endowed with rich biological resources. found in the Philippines (BMB-DENR 2019). The country It is host to about 15,000 species of plants representing 5% occupies the 4th place in the world in terms of hosting the of the total floral species in the world (Lasco et al. 2013), highest number of endemic bird species (BMB-DENR placing the country at the 5th rank globally (BMB-DENR 2016, as cited by Ani and Castillo 2020). 2016, as cited by Ani and Castillo 2020). In terms of faunal species, the Philippines is home to a total of 38,000 species In recognition of the biological richness of the Philippines, the country is tagged as one of the 18 megadiverse *Corresponding Author: [email protected] countries. The said countries altogether contain around 271 Philippine Journal of Science Pulhin et al.: Vegetation Analysis Sanctuary Vol. 150 No. S1, Special Issue on Biodiversity and Forest Areas of KFR 70–80% of the world’s biodiversity (Lasco et al. 2013). METHODOLOGY Through time, however, the biodiversity of the country has eroded putting the Philippines as one of the hotspots Description of the Study Area for biodiversity loss. As of 2019, there are 60 critically The KFR is located in Cluster 1 of Ikalahan-Kalanguya endangered, 61 endangered, 440 vulnerable, and 545 Ancestral Domain in the provinces of Nueva Vizcaya and other threatened wildlife species in the Philippines Pangasinan (Figure 1). It covers 14,730 ha of mountainous (DENR 2019). In terms of flora, there are 179 critically land with elevation ranging from 600–1717 m above sea endangered, 255 endangered, 406 vulnerable, and 145 level. The average rainfall recorded is over 4000 mm/yr other threatened species as of 2017 (DENR 2017). and temperatures between 8–24 °C. The erosion of biodiversity is caused by massive KFR was set aside for the Ikalahans through the memorandum deforestation and forest degradation that occurred in the of agreement no. 1 signed on 13 May 1974. It covers six country. From 90% forest cover in the 1900s, it went “barangays” (municipal districts; Brgy.) – namely, Imugan, down to 70% by the end of the 19th century (Lasco et al. Malico, Sta. Rosa, Unib, Bacneng, and Baracbac (Figure 2001; Garrity et al. 1993; Liu et al. 1993). By the year 1). KFR is one of the remaining intact habitats for wildlife 2015, only 23% (7 Mha) of the country is covered with and forest species. The area is characterized by diverse flora forest, which is broken down into closed forest (2 Mha), and fauna ecosystems, as evidenced by the presence of open forest (4.7 Mha), and mangrove forest (0.3 Mha) threatened species of plants and animals. It is also the home (FMB-DENR 2018). of the Ikalahans, a cultural minority group characterized by Loss of biodiversity habitats and degradation is caused by a unique culture and practitioners of sustainable agroforestry a number of factors: “kaingin” (slash-and-burn farming), systems. The reserve mountain contains three major types mining, climate change, typhoons, floods, landslides and of forest – 1) pine forest on the western side, 2) dipterocarp road construction, settlement, conversion into built-up forest on the eastern portion, and 3) mossy forest on the areas/subdivisions, legal and illegal logging, charcoal central part. Within the reserve, sanctuary forests were set making, timber poaching (Carandang et al. 2012), aside for watershed and wildlife protection while other overpopulation, lack of capacities on natural resources portions were composed of agroforestry farm, agricultural, management, under-valuation of ecosystem services and grassland areas. from natural resources, weak integration of biodiversity concerns in landscape planning, and rights overlap with Vegetation Sampling Procedure defined areas for protected areas (PAs) (BMB-DENR A reconnaissance survey was conducted to identify 2019). In addition to the loss of habitats and degradation, the areas in KFR that were included in the vegetation biodiversity is threatened by overexploitation for trade or sampling. Within the reserve, only the sanctuary and leisure, pollution, and the introduction of invasive alien forested areas were surveyed. A modified QSM was species (BMB-DENR 2019). applied. A total of eight 1-km transects with 20-m width Conserving biodiversity is very important as it offers a was established to ensure that a substantial portion of the number of services such as water, food, pharmaceuticals, KFR was sampled (Figure 2). biomass fuels, carbon sequestration and climate Figure 3 shows the sampling scheme used in the study. regulation, crop pollination, cultural, intellectual and The sampling was undertaken in three layers: overstorey, spiritual inspiration, and ecotourism (BMB-DENR intermediate, and understorey. For the overstorey layer, 10 2019). Before biodiversity conservation can be done, plots each measuring 10 m x 10 m, spaced 100 m away baseline information on the diversity of the species from each other, were alternately established in each present in the area is needed. Furthermore, having 1-km transect. Inside each 10 m x 10 m plot, a smaller biodiversity data is important as it can aid in better plot measuring 3 m x 3 m was established to assess the planning and management of the area. Most biodiversity intermediate layer. Inside each 3 m x 3 m plot, a smaller assessments in the Philippines were undertaken plot measuring 1 m x 1 m was constructed to cover the in declared PAs. However, there are a number of understorey layer. A total of 240 plots were established biodiversity-rich areas in the country, one of which is as follows: 80 plots (10 m x 10 m), 80 plots (3 m x 3 m), the KFR, where no assessment has been done. Thus, a and 80 plots (1 m x 1 m). vegetational analysis of the KFR was conducted to help fill such a gap. This paper presents the biodiversity Only trees with a diameter at breast height (DBH) of > 5 resources present inside the KFR. were measured in the 10 m x 10 m plots. Trees with DBH < 5 cm and more than a meter height were sampled inside the 3 m x 3 m plots. In the 1 m x 1 m plots, plants with DBH < 5 cm and less than a meter height were identified. 272 Philippine Journal of Science Pulhin et al.: Vegetation Analysis Sanctuary Vol. 150 No. S1, Special Issue on Biodiversity and Forest Areas of KFR Figure 1. Location map of KFR. Figure 2. Location of transects established in the assessment. 273 Philippine Journal of Science Pulhin et al.: Vegetation Analysis Sanctuary Vol. 150 No. S1, Special Issue on Biodiversity and Forest Areas of KFR Figure 3. Transect and plot designs. Taxonomic Characterization Importance value index. Importance value is a measure All specimens observed within the established transect to assess the overall significance of a species since it were collected and labeled using their local names. takes into account several properties of the species in Local names were verified based on the morphological the vegetation. In calculating this index, the percentage and vegetative characters of the specimens in the values of relative density, relative frequency, and relative Kalahan Educational Foundation and the University of dominance are summed up together (Curtis 1959). the Philippines Los Baños – College of Forestry and (4) Natural Resources herbaria. The 1999 Revised Lexicon of Philippine Trees was also used for further verification Relative density.