This is my HOME...: BIOLOGICAL DIVERSITY (Biodiversity)

Philippine Biodiversity: Species Richness and Abundance

Angel C. Alcala
Academician and University Research Professor, Silliman University, Dumaguete City

The term biodiversity, coined by Walter Rozen of the United States Academy of Science in 1986, was first used by E.O. Wilson, the famous Harvard biologist, in 1988. Since that time, it has become increasingly popular among biologists, and is now entrenched in the scientific literature. The term encompasses the total richness and variety of life on earth. Biodiversity studies are directed at five levels of biological organization: gene, species, population, community, and ecosystem. This paper will focus on Philippine biodiversity at the species level.

The Philippines is one of the countries that exhibit high species richness. An estimated 13,500 species of terrestrial plants are found in the country, 8,000 of which belong to the flowering group. About 40% of flowering plants are endemic. Of economic and scientific interest are 39 species of trees in the Family Dipterocarpaceae, the source of Philippine mahogany. The resident and breeding terrestrial vertebrate animals in the Philippines comprise about 911 species. The approximate numbers of land vertebrate species are 100 amphibians (ca 80% endemic); 240 reptiles (ca 70% endemic); 396 birds (ca 44% endemic), and 175 mammals (ca 64% endemic). The country compares favorably with Brazil and Madagascar, two countries known for their outstanding biodiversity. The Philippines (land area 300,000 square kilometers) has about 529 endemic species of terrestrial vertebrates, while Brazil (28 times larger in area than the Philippines) has 725 endemic species. Madagascar (twice larger than the Philippines) has fewer unique mammals (90) than the Philippines (111). The Philippines possesses no extensive freshwater habitats, but Lake Lanao was reported to harbor about a dozen endemic species in three or four genera of true freshwater fish of the Family Cyprinidae.

The species richness of corals, shells and fish is very high in the fertile triangle formed by the Philippines, New Guinea and the Malay Archipelago. Some 400-500 species in 90 genera of hermatypic (reef-forming) corals and ca 4,000 species of marine fishes are believed to have existed in this area. The 900,000-square-kilometer Sulu-Sulawesi Sea (part of this fertile triangle) is home to 2,500 species of fish (including a species of coelacanth), five species of marine turtles, and 22 species of marine mammals. However, small reef systems harbor much fewer fish species. For example, 200 species have been observed on two reefs in the Central Visayas over a period of 30 years. Pristine reefs in the country such as Tubbataha Marine Park should have more than this number.

For the Philippines, the factors that are responsible for the high species richness in old-growth tropical rainforests are (1) geologic age (main land
masses more than 50 million years old), (2) tropical location providing equable climatic conditions, (3) environmental heterogeneity as shown by diversification and complexity of microhabitats, (4) insular (island) condition, and (5) contiguity to a large land mass (Asia) and islands in the south and southeast serving as source of immigrants. The first four factors have favored the development of new species (speciation) through evolutionary processes operating on biological
and genetic materials of immigrants. Movements and distribution of terrestrial species are limited by natural barriers that influence speciation processes such as bodies of water, high mountain peaks, and in modern times by cultivated areas.

In contrast, oceans and seas tend to be connected to each other. Oceanographic processes, including water mass movements, ocean currents, etc., provide the mechanisms to transport marine propagules and to connect distantly located marine areas. For example, the Pacific Ocean connects to the Sulu Sea through ocean currents in the Bohol (Mindanao) Sea moving southwestward, and the South China Sea connects to the Sulu Sea through the Mindoro and Balabac Straits. Because of this connectivity, mixing of genes in
marine species populations occurs, and endemism is lower in marine organisms than in terrestrial ones. This is illustrated by the similarity and the low endemism of corals and reef fishes of the Philippines. Because of the wide distribution of marine propagules over large areas of oceans, the incidence of species extinction among marine species is also low. The differences between terrestrial and marine environments imply that approaches to biodiversity
conservation would also differ between terrestrial and marine species.

As widely known, Philippine biodiversity has been affected by not only natural events but also human-induced factors especially during the past 50-60 years. The effects of man’s activities on Philippine biodiversity may be assessed in a general way in terms of two measures, species richness and abundance, using groups of terrestrial organisms (rainforest trees and land vertebrates) and marine organisms (corals and reef fishes), for which a certain amount of data exists.

The Family Dipterocarpaceae, comprising 39 species in the Philippines, is now represented by only 14 species in several limestone forest fragments with a total area of ca 300 ha in southwestern Negros Island. The number of species that may have gone extinct during the past years is not known. However, there is little doubt that abundance of this tree family has been reduced because of forest degradation. The various vertebrate groups in these forest fragments have shown variable responses to human impacts. The amphibians and reptiles have lost more than 20% of the species occurring there 50 years ago. The birds appear to have lost a few endemic species. The mammals, especially the volant species (fruit bats), have not lost any species during the past 50 years, but a couple of species have become rarer and are on the verge of extinction. The large herbivores have also shown reduction in population size. The degradation of Philippine coral reefs has been sufficiently documented. Only about 5% of coral reef sites explored have at least 75% live coral cover, and 70% of the surveyed sites have only 25% cover or less. The majority of coral reefs have much reduced numbers of carnivorous fishes (fish eaters or top carnivores), and some have virtually none of these fishes. However, no coral or top carnivores have been shown to be extinct. Density of reef fishes in general is low (<>100 kg/1,000 sq m in more pristine or protected reefs.

The loss or decline of species richness and abundance of terrestrial and marine species in the Philippines has serious negative effects on the social and economic well being of our people. Efforts to protect what remain of our biodiversity are urgently needed.

Biodiversity is usually considered at three levels, namely:

Genetic diversity - is the sum total of genetic information contained in the genes of individual organisms that inhabit the earth.
Species diversity - is the variety of living organisms on earth which is estimated to be between 5 and 50 million or more (only about 1.75 million or 13% of the totalnumber of species on earth has been described). One measure of biodiversity would be the number of species (a group of organisms genetically so similar that they interbreed and produce offspring).
Ecosystem diversity - relates to the variety of habitats, biological communities, and ecological processes in the biosphere.

Importance of Biodiversity
Biodiversity is the foundation of healthy and functioning ecosystems - the fountains of opportunity for all people. Rich soils, clean air, and water abundant forests - the complexity of nature and the myriad species they support- are essential for thriving societies.
Biodiversity is estimated to have contributed 33 trillion US dollars to the global economy (Constanza, et al., 1997) yet few people realize its value.
In the Philippines, the extent of biodiversity loss has reached alarming proportions - so much so that some international experts have proposed to write off as global biodiversity disaster area.

The Global Significance of Philippine Biodiversity:
The Philippines is an archipelago of more than 7,107 islands covering an estimated land area of 30 million hectares. Its archipelagic waters cover an estimated 220 million hectares or approximatel 88% of the Philippine territory. The country's complex geological history and long periods of isolation from the rest of the world have produced varied life forms, water bodies and climatic conditions. These, in trun have, contributed to the wide array of soil, temperature, moisture, and weather regimes and combined with its extensive areas of rainforest and its tropical location, have given rise to high species diversity and endemism.

The country has more than 52,177 described species, of which, more than half ar found nowhere else on earth. There are many more species that are unknown to science.

The Philippines is considered one of the 17 megadiversity countries. As such, Philippine biodiversity is an integral part of our global heritage and is one of the most important countries in the world for conserving diversity of life on earth.

Terminologies:

Threatened Species - species of organism that could become extinct if a critical factor in their environment were changed.
Endangered Species - those species that are present in small number that they are in danger of becoming extinct
Extinct - those species that existed in the past, but representative members can no longer be found at the present

A great number of rare and exotic animals exist only in the Philippines. The country's surrounding waters reportedly have the highest level of biodiversity in the world. But this distinction was soon overshadowed by the fact that the Philippines has been dubbed as the "hottest of the hotspots" by no less than the Conservation International.

The Philippines is considered as a mega diversity country and a global biodiversity hotspot. In the 2000 Red List of the International Union for the Conservation of Nature and Natural Resources (IUCN), 418 of the country's 52,177 species were listed as threatened. The country is home to about 9,000 species of flora, a third of which is said to be endemic to the country. It hosts 165 species of mammals, 121 of which can be found only in this part of the world. The Philippine Biodiversity Conservation Priority-setting Program (PBCPP) described these 165 endemic mammal species as endangered or critically endangered.

There are also 332 species of reptiles and amphibians living in the country, 215 of them endemic to the archipelago. It is said that less than 14 of the 114 total species of snakes in the country are poisonous. Several species of frogs and other reptiles remain to be documented. Unfortunately, several species were believed to have vanished without being studied.

In 1953, Albert Herre identified 2,117 species of fish in Philippine waters. These included 330 species of endemic freshwater fish. Whales, dolphins and whale sharks have also been visiting Philippine waters near the islands, allowing sightings by both marine scientists and commercial fishermen. About 500 of the 800 known coral reef species in the world are found in Philippine waters.

The country also has the highest concentration of birds and butterflies in the world. There are some 86 species of birds and 895 species of butterflies in the country. About 352 species of butterflies are endemic to the Philippines.

Many of these biological wonders are now in danger. The main culprit is human's indiscriminate use of the country's natural resources, resulting in an unabated denudation of the Philippine rainforests. In the last 500 years, the Philippines saw the destruction of over 93 percent of its original forest cover. Only about 5 percent of the country's 27,000 square kilometers of coral reefs were in excellent condition.

According to the Department of Environment and Natural Resources (DENR), the country's total forest size dwindled to 6.7 million hectares in 1990 from 30 million hectares in 1930. At the same time, the forest-to-man ratio shrank to 0.1 hectare per Filipino in 1990 from 1.13 hectares per Filipino in 1930. By 1996, experts claimed that only 1.8 million to 2.4 million hectares or 6 to 8 percent of original vegetation were remaining.

A study by the Philippine Congress said that 123,000 hectares of the country's forest cover are lost every year. The study added that by 2036, there would be no forest left in the Philippines, unless reforestation is started.

In January 2003, a study by the Green Tropics International (GTI) claimed that the Philippines would need P30 trillion to reforest country's denuded mountains in over 85 years.

Problems and Threats

Biodiversity loss in the Philippines stems from 4 broad categories:

Habitat destruction - anthropogenic causes : logging, fires, land conversion, siltation, destructive fishing methods, encroachment and occupance in protected areas. Natural Causes : volcanic eruptions, earthquakes, typhoons, pests and diseases.
Overexploitation - overharvesting and unsutainable use of resources due to poverty, population pressure, ignorance, paucity of livelihood opportunities, wrong values, and unrestrained and unregukated access to natural resources.
Environmental pollution - chemical waste from mine tailings, hazardous wastes from industrial plants, factory discharges, agricultural pesticides and fertilizer, and household wastes. Pollutants overwhelm and overtax the dispersal and self-cleansing capacity of our atmosphere, water bodies and land.
Biological pollution - introduction of exotic species at the expense of the endemic and indigenous species through predation, parasitism, competition, hybridization, and habitat alteration.
Weak Institutional and Legal capacities - inappropriate, ovetapping, conflicting, and obsolete policies and institutions: shortage of technical expertise, shortage of funds, weak information, education, and communication, poor integration of research and development activities.

Impact of Biodiversity Loss in the Philippines

floods and landslides
destruction of crops, fisheries, homes, roads, bridges
shortage in availability
loss of human lives
economic crisis (loss of billions of pesos)

Initiatives/Institutions In-charged of Conservation

PAWB - Protected Areas and Wildlife Bureaus was tasked at handling the establishment and management of the country's protected areas and the conservation of biological diversity.

DENR - was assigned the formulation of the Philippine Strategy for Sustainable Development.

PCSD - Philippine Council for Sustainable Development hel fulfill the Philippines' commitment to the Convention on Biological Diversity

NIPAS Act - National Integrated Protected Areas System Act became the basis for the establishment and management of protected areas.

NBSAP - National Biodiversity Strategy and Action Plan sets forth the strategies and actions that the country will pursue to conserve its biodiversity.