Mt. Hamiguitan Range Wildlife Sanctuary in Mindanao, Philippines is the only protected forest noted for its unique bonsai field or ‘pygmy’ forest of 100-year old trees in an ultramafic soil. Mt. Hamiguitan has been found to have five (5) vegetation types and these are the agroecosystem, dipterocarp, montane and typical mossy and the mossy-pygmy forest. This serially nominated property is found to possess high and varied ecosystem with many endangered, endemic and rare species of flora and fauna. One of the endangered bird species located is the majestic Philippine eagle (Pithecophaga jefferyi). It has been identified by Conservation International as one of the Philippines ‘hotspots’ that is included by the Philippines Eagle Alliance as one of the first priority sites in Eastern Mindanao for conservation and protection. The Philippine eagle is of outstanding universal value for science and conservation, whose nesting and feeding areas are located in dipterocarp forests including closed canopy forests. It is the second largest eagle in the world. The aviator Charles Lindbergh, as representative of the World Wildlife Fund, proclaimed it as “the air’s noblest flyer.” The Philippine eagle is the nation’s symbol and is locally known as “haribon” or bird king. With a wingspan of two meters, this bird of prey boasts the largest surface area in its wings among all eagle species. Like the giant panda of the Sichuan Giant Panda Sanctuary, recently inscribed as a World Heritage Site at the 30th Session of the World Heritage Committee in Vilnius last July, the Philippine eagle is a wonder of nature of great charisma. This bird is not found elsewhere in the world and has become the symbol of Philippine conservation efforts. Widespread destruction of its habitat and collection is driving this species to extinction.
The 6,834-hectare total surface area of Hamiguitan Range Wildlife Sanctuary is characterized by five (5) vegetation types, namely, agro-ecosystem (75-420m asl), dipterocarp (420-920m asl), montane (920-1160m asl), typical mossy (1160-1350m asl) and the mossy-pygmy forest (1160-1200m asl). Each of these forest type harbors endemic, threatened, rare and economically important species of flora and fauna. The mossy-pygmy forest occupies approximately 225 hectares of the sanctuary. Trees have an average height of only 1.4m with a diameter of 8 cm. Two dominant species that can only be found in this forest type are Leptospermum flavescens and Wendlandia nervosa. Other species include Tristaniopsis micrantha, Dacrydium elatum, Calophyllum blancoi, Symplocos polyandra, and Agathis philippinensis (Almaciga) which has the highest average height of only 2.4 m. Madulid (1991) reported that this type of vegetation is associated with ultramafic species, such as, Calophyllum sp. Norman (2004) explained that the stunted growth of trees could be attributed to a high concentration of chromium, iron, nickel and magnesium in soil.
Inventory of flora species in each vegetation type revealed that the montane forest has the highest species richness of plants with 462 species, followed by dipterocarp forest with 338 species. Mossy and agro-system have the lowest species richness value of 246 each. The highest diversity index of trees (1.7) could be observed in the montane forest while a diversity index of 1.273 was observed in the mossy forest. The mossy-pygmy forest has the highest diversity index (1.498) for shrubs, herbs and vines. Assessment of the conservation status of the 477 identified species revealed that 163 species (18.56%) are endemic, 35 species (3.99%) threatened, 33 species (3.75%) rare and 204 species (23.23%) economically important. Eight (8) species, namely, Elaeocarpus verticillatus, Patersonia lowii, Astronia lagunensis, Nepenthes argentii, N. mira, Schizaea inopinata and S. malaccana, have been found to be new record in Mindanao and one species, Nepenthes maxima, as new record in the Philippines. Based on sampling plots, endemicity of trees per vegetation type revealed that as elevation increases, endemic species also increase. This property is therefore found to be very rich in endemism.
The IUCN Red List has identified at least 11 endangered vertebrate species. The Philippine Council for Agriculture, Forestry and Natural Resources and Development (PCARRD) reported that the mountain is inhabited by five endangered species, 27 rare species, 44 endemic species and 59 economically important species. In July 2004, the Mt. Hamiguitan Range has been declared under Republic Act 9303 as a protected area under the category of wildlife sanctuary. Out of the 14 species of mammals observed in Hamiguitan Range, seven species (50%) were found as Philippine endemic and three species (21.4%) as Mindanao endemic with six threatened species. Two endemic species of mammals in Hamiguitan Range, Acerodon jubatus (Golden-crown Flying Fox) and Tarsius syrichta (Philippine Tarsier) are endangered; three endemic species are vulnerable, Sus philippinensis (Philippine Warty Pig), Cervus mariannus (Philippine Brown Deer), and Haplonycteris fischeri (Philippine Mossy-pygmy Fruit Bat); and one endemic species is threatened, Paradoxurus hermaphroditus (Asian Palm Civet). For birds, a total of fifty-three species were found, of which ten species (18.9%) are Mindanao endemic and 20 species (37.7) are Philippines endemic, respectively with four threatened species. Two endemic species of birds, Phapitreron cinereiceps (Dark-eared brown dove) and Pinelopides panini (Tarictic Hornbill) are endangered; one is near-threatened, Aethopyga primigenius (Grey-hooded sunbird) and one vulnerable, Mimizuku gumeyi (Giant-scoop Owl).
Mount Hamiguitan Range Wildlife Sanctuary belongs to the 15 biogeographic zones in the Philippines considered to have the highest land-based biological diversity in terms of flora and fauna per unit area. This site is therefore nominated for inclusion in the UNESCO World Heritage List for its outstanding universal significance.