Northern Sierra Madre Natural Park: Biodiversity, Threats and Conservation of Flora and Fauna Species
Dela Paz, Rich Bernice S., Dimalanta, Kristine Joie M., Duran, Jo Dexter R.,
North Sierra Madre Natural Park (NSMNP) is located on the north-eastern part of Luzon, with an area of 359,486 hectares, 257,861 of which is terrestrial habitats and 71, 652 is marine. (Biodiversity Management Bureau, 2015). This stretch of land is found in between the provinces of Aurora and Cagayan and is known to occupy the midsection of the Sierra Madre Mountain range.
The terrain mainly consists of low hills to a large number of steep slopes near the coasts due to its mountainous characteristics. In this stretch of land, the highest peak is Mt. Cresta which lies 1672 above sea level, to be followed by Mt. Divilacan which is 1311 masl. (Biodiversity Management Bureau, 2015) These two mountains serve as landmarks for the division between the eastern and western areas of Sierra Madre Mountain range in the Park.
More features found in the park include extensive white sandy beaches and clear blue water, large coral reefs that are pristine in condition. Thus, resulting into a rich marine life with an abundant number of sea creatures. (Biodiversity Management Bureau, 2015).
NSMNP is recognized for its diverse ecosystems and its historical, cultural and economic importance to the Philippines. It is also known by the people because it is one of the last remaining rainforests in the Philippines. Relative to its big size, it houses an extensive number of species of endemic plants and animals.
30% of the endemic species are birds, and 62% are the mammals (Ploeg, Weerd, Masipiquena & Persoon, 2012). Within this number of animals, there are 35 globally threatened species recorded. Some of which are the Philippine eagle (Pithecophaga jefferyi), Golden crowned flying fox (Acerodon jubatus), Isabella oriole (Oriolus isabellae), green sea turtle (Chelonia mydas), loggerhead turtle (Caretta caretta), Philippine crocodile (Crocodylus mindorensis) and many more (Ploeg, et. al., 2012). Aside from animals, there is also an existing threat against the trees that also caused endangerment towards them. Some of these endangered trees are the Narra Tree (Pterocarpus indicus), Tabog (Swinglea glutinosa) and many more (Biodiversity Management Bureau, 2015). As previously mentioned, there are rising threats against the wildlife and agricultural lands. These are mostly due to hunting and depletion of forests by illegal logging. Because of these rising threats, actions have been made by the government in order to protect and conserve this land. In the 22nd of April 2001, a proclamation (proc. No. 9125) was made by the president, Gloria Macapagal-Arroyo, stating that NSMNP is protected under the category of natural park, with the purpose of preserving the biodiverse ecosystems in the area. People should also recognize the endemic species living in the area and know their importance and impact on the environment. (Ploeg, Weerd, Masipiquena & Persoon, 2012).
In the park, local communities are also present, one of which is Agtas, an indigneous population consisting of 9000 individuals. They live along the coasts and along the mountain ranges of Sierra Madre (Minter, 1977). These people are hunters and gatherers that came from a Negrito population, and so they practice the traditional way of living (Minter, 1977). Their livelihood mainly consists of swimming, fishing and hunting wildlife such as boars and deers. However, there have been reports that these activities have decreased because of forest loss. (Biodiversity Management Bureau, 2015).
The NSMNP is credited for its rich biodiversity holding a myriad of flora and fauna species. It is considered as one of the ten Key Biodiversity Areas of the Philippines managed by the Department of Environment and Natural Resources (DENR), making it a priority site for biodiversity conservation in the Philippines (Ambal, Duya, Cruz, Coroza, Vergara, De Silva, Molinyawe & Tabaranza, 2012). The NSMNP is comprised of twelve major habitat sites, nesting several endemic, globally threatened and near-threatened species of animals such as the well-known Philippine Crocodile (Crocodylus mindorensis), the Philippine Eagle (Pitheciphaga jefferyi) and the Acerodon jubatus, or more commonly known as the Golden-crowned flying fox (Tan, 2000). On the other hand, several endemic and rare plant species are also located within the vicinity of the protected area such as: Narra tree (Pterocarpus indicus), Mabolo or Kamagong (Diospyros discolor), Tabog (Swinglea glutinosa), Red lauan (Shorea negrosensis), and Pagatpat (Sonneratia caseolaris).
In a recent biodiversity survey, it is indicated that NSMNP contains almost 60% different plant species found in the Philippines. Those 60% are seen in the 12 major forest formations and coastal habitats of the park. There are five existing kinds of forest that are seen, these are the beach forest, mangrove forest, ultrabasic forest, limestone forest, and the lowland evergreen dipterocarp rainforest (Tan, 2000). Each kind of forest exhibits diversity in NSMNPs floras, some of them are presented below:
Pterocarpus indicus or narra tree is known to be the national tree of the Philippines. It thrives in tropical or subtropical climate and locations most especially in a moist, sandy loam or clay loam soil (Ecosystem Research and Development Bureau, 2010). Narra trees are known to be deciduous, tall (grows up to 160 feet tall), and well adapted to strong winds in such a way that it can withstand a typhoon and only a branch breakage as an effect. The growth rate of this plant is dependent on where it is located. Those in light shaded sites that also receives abundant sources for their needs can grow about 6.6 feet per year but those that are in an open area develops multi-stemmed and branchy features, but they arent able to grow as tall as the previous ones. (Thompson, 2006). Moreover, narra trees are known to be a perennial, it lives for multiple years thus, narra sheds its leaves during dry seasons as a kind of coping mechanism to sustain its needs for survival. Narras are angiosperms which means they produce flowers and fruits. Its flowers are numerous, bright yellow in color and those flowers that grew singularly are very visual and fragrant. The fruits are pod-like shaped, flat and orbicular, it contains 0-5 seeds inside. (ERDB, 2010). Knowing that they possess flowers, they reproduce by pollination but in some ways, they also reproduce asexually by these methods: grafting and stem cutting. This species is also known as a multipurpose tree where in it can be utilized as a timber and even for medicinal uses. Narras are efficient for building furniture and other objects like musical instruments and even handicrafts, this is because of their durability and richness in color. In addition, narras are also highly durable when it comes to decaying situations. More so, it is also used for medicinal purposes came from the shredded bark, root juice and leaves. These are used in treating tuberculosis, headaches, mouth ulcers, rheumatoid arthritis and much more. (Thompson, 2006).
Diospyros discolor is one of the premium woods recognized here in the Philippines together with the Narra (Pterocarpus indicus) and Molave. Due to its great features, Philippine law protected it from extraction from the forest through a Special Private Land Timber Permit issued in 1990 by the Department of Environment and Natural Resources (DENR). Nevertheless, the threat to its extinction was not mitigated, in 2007, it was declared in Administrative order No.01, issued by the DENR, that Mabolo tree or Kamagong belongs to the critically endangered species of plants. (Probar, 2012). Kamagong can be sited at locations that are in primary and secondary forests at low and medium altitudes; can be seen at the limestone forest of NSMNP. They grow up as high as 100 feet with evergreen leaves, but it is a slow-growing plant. Its leaves are almost sclerenchymatous, due to its leathery kind of texture, but the abaxial surface has the dominating presence of trichomes. Moreover, they flower during the start of the year until June wherein they undergo reproduction to produce their fruits usually, during June up until September (rainy season) (ERDB, 2006). Their fruits often borne in pairs, its dimensions are sizing to an apple, rounded, and fleshy; it radiates a maroon or purple color when ripe. In reproduction, male species of this plant are approximately close to the female species for a convenient pollination and exchange of gametes. (Morton, 1987). Their This tree is known as the iron-wood due to its unbreakable capacity therefore it is a good material to use for construction most especially is considered as a heavy wood that assures the stability of structures. In addition to this is that its fruit emanates an unpleasant odor but in contrary it contains a lot of vitamins and nutrients such as calcium, vitamin B, iron, and proteins and also provide powerful antioxidant. (Pobar, 2013 & Morton, 1987).
Swinglea glutinosa is pertained to as a small thorny tree in the Citrus family that grows well in the Philippines due to its suitable temperature. It prefers tropical climates with a temperature of 32.2°C in a controlled environment. (Purcaro, Schrader, Burandt, DellaGreca, & Meepagala, 2009). It is known to be perennial with leaves that are evergreen, it grows as high as 24-30 feet, though its trunks are not that wide. This plant exhibits maturity by the development of its flowers and fruits. The floral anatomy of Tabog is discovered by Tillson in 1938 saying that its lateral sepal bundles are fused as they grow out from the axis with the petal midrib bundles. (Tillson, 1938). Its flower either grows solitary or in clusters, it is white in color, small and fragrant. Nevertheless, its flower is a complete and perfect flower for it has the presence of petals, pistil, and ovary that are short-stalked, style that are slender and twice as long as the ovary. They are capable of sexual reproduction through pollination and also asexual reproduction in ways such as grafting. Moreover, the fruit of Tabog exhibits a remarkable feature called mucigel glands that acts as the oil glands of this specific fruit. Its fruit is inedible, so it is just used as ornamentals, but it also has numerous medicinal benefits.
In the Philippines, Shorea negrosensis is known as the red lauan or the red mahogany that is endemic to the country. Due to illegal logging, this species has been already labeled as critically endangered. This caused the limited number of researches about this plant. This kind of plant is seen in the tropics, they are known to be tall (can grow up to 50 meters in height) and are seasonal evergreens. They are perennials and known to live for centuries and inhabit coastal to inland, riverine to swampy and even dry lands (Symington 1943, Wyatt-Smith 1963). They produce flowers and fruits (produce five long wings or in other words imbricate sepals) that makes them capable to reproduce. Their main pollinators are insects and wind. The factors that makes them vulnerable to extinction are their helpful features such as for the use of timber, furniture, and medicine. Their barks is considered valuable and strong good for making furniture such as flooring, interior and exterior joinery, etc. in addition, their bark contains an agents good for an adhesive purpose that can be used in leathers called tannin. Moreover, researchers have discovered that Shorea negrosensis wood extract inhibits tumor (Ragasa, Ng, Ebajo Jr, Fortin, De Los Reyes & Shen, 2014).
Scientific name: Sonneratia caseolaris
Sonneratia caseolaris or famously known for mangrove apple are the small type of tree that grows for about 5-20 meters tall. They are mostly marine seen among mangrove area but never on coral banks. It is considered an evergreen tree that has adapted to its source of water which is saltwater by means of their unique rooting system. Some of the species are also found flourishing in freshwaters. They possess flowers and fruits as their means of reproducing. Their flowers are uniquely beautiful possessing the characteristics of having a red-colored petal which is surrounded by its numerous long white showy stamens. When it blooms, it only occurs in the span of one night, but they emanate an unpleasant odor. Moreover, their fruits are relatively small with a diameter of 4 cm that is closely similar to a large berry with a star-shaped base. The production of their seeds are seasonal, vegetative parts fall sooner than its reproductive parts. There rate of seed dispersal dependent on the salinity they are exposed in, they mostly produce a great amount of litter during the summer. Fruits of such species can contribute medically in such ways that they cease hemorrhage, treat coughs and even help in curing hematuria.
When it comes to the faunal diversity and endemism, based on the 2001 Ecosystem Profile, the Park accounts for at least 80% of birds in Luzon with 89 species being endemic to the NSMNP, such as the Isabela Oriole (Oriolus Isabellae). Aside from birds, other taxonomic groups were also recorded from the protected area, such as 38 species of mammals having 55% endemism which includes the Northern Luzon Giant Cloud Rat (Phloeomys pallidus) and the Golden-crowned Flying fox (Acerodon jubatus); On the other hand, the Northern Sierra Madre Forest Monitor (Varanus bitatawa) and the critically endangered Philippine Crocodile (Crocodylus mindorensis) is part of the 16 out of 40 species of reptiles that are endemic to the NSMNP protected area; Lastly, 12 amphibians (more than 70%) are found only within the vicinity of the Park.
The NSMNP serves as the last nesting place for the Isabela Oriole (Oriolus Isabellae) which is classified as Critically Endangered under the International Union for Conservation of Natures (IUCN) C2 criterion, considering its rapid population decline at a rate of 20% in two generations due to the extensive loss of forest habitat (Van der Ploeg & Van Weerd, 2010). Just like other Oriole species, it is an omnivorous animal that consumes mostly insects and fruits. Features of the O. isabellae include having olive-green upperparts, olive-brown wings, and yellow underparts. The heavy dark grey bill distinguishes the Isabela Oriole from its close appearance to the White-lored Oriole who has a slender and dark red bill (Collar, 1998).The distribution range of this species within the NSMNP is said to be extant, meaning it occurs presently in the area. Orioles are considered to be solitary and monogamous birds, but during the breeding season, they whistle three to four syllables in order to find a mate. Female Orioles lay two to four eggs with black to brown spots in its shell and incubate them for 16 to 18 days. Once hatched, the young would be fed through regurgitation from their parents. The Oriolus isabellae and other bird species are responsible for natural ecological processes that benefit human society (Wenny, Devault, Johnson, Kelly, Sekercioglu, Tomback & Whelan, 2011). Specifically, the O. isabellae have numerous roles within the NSMNP community such as consuming pest species, pollination, seed dispersal and endozoochory, which is the dispersal of seeds via ingestion and long-distance migration (Whelan, Wenny & Marquis, 2009).
Murid rodent species native in the Philippines range from small shrews that live on the ground to large cloud rats that occupy trees (Heaney, Balete, Dolar, Alcala, Dans, Gonzales, Ingle, Lepiten, Oliver, Ong, Ric kart, Tabaranza & Utzurrum, 1998). One example of a cloud rat is the nocturnal, forest-dwelling Phloeomys pallidus, or most commonly known as the Northern Luzon Giant Cloud Rat. Despite having the word giant in its common name, this nocturnal rat only weighs approximately 4.2-5.7 lbs. (1.9-2.6 kg) but its total length ranges from 75-77cm. Their pelage is mostly a combination of white to pale gray with dark brown or black markings on their face. A slender 11-12.5 inches densely furred tail is also seen in this animal. Lastly, the P. pallidus have large hind feet with long claws which help them climb trees since they spend most of their time high in the branches, where they also get their food such as young leaves and fruits. In terms of reproduction, species of P.pallidus often live in pairs. They give birth to only one young per annum, which is born in hollows of trees or holes in the ground. Female cloud rats have an estrus cycle of 10-15 days where they allow male cloud rats to lick their bodies and do the same in return. The estimated gestation period ranges from 65-95 days which also shows physical pregnancy signs such as reddish nipples and increase in girth (Pasicolan). The Northern Luzon Giant Cloud rat is listed among Least Concern species, based on the IUCNs species criterion. The oldest known cloud rat is recorded to be 13 years which was undertaken care of a human. This species is being threatened by hunting, as it is being taken for food. Rats are often treated as nuisances. We often think of them as useless, but in reality, these animals also have a role in our ecosystem, one of which is the dispersal of seeds within the ecosystem that they inhabit.