Kinds of Ecosystem

A. Natural Ecosystems

Considering the wide variety of Philippine habitats, the same can be expected of natural ecosystems in the country. However, only three types of natural ecosystems are described below.

1. Forests

Because the Philippines is close to the equator (between 4^o 23’ and 21^o 25’ North Latitude) and surrounded by a vast expanse of ocean, the country receives a high rainfall (around 200 mL per year); it is classified as a tropical rain forest biome.

Original forests are called virgin forests or primary forests. Large forest areas are at times destroyed by careless logging and kaingin farming and, sometimes, by forest fires. As long as seeds of forest trees reach the area and water is available, the destroyed area soon becomes covered with trees again. The new growth is called a second-growth forest or secondary forest.

In the Philippines primary forests in the lowlands include mangrove forests, beach forests, dipterocarp forests and molave forests. In the highlands, primary forests include pine forests ( such as those found in the Mountain Province, the Zambales mountains, and Mindoro mountains) and mossy forests (or tropical upper mountain rain forests).

The richest type of tropical rain forest is the dipterocarp forest. It has the highest number of plant and animal species. The thick canopy is a rich habitat of birds, while the thick layer of decaying leaves beneath the trees is a rich habitat of leeches, millipedes, centipedes, and land snails. Mammals, birds, reptiles and invertebrates abound on the trees, on the ground and in the soil.

Then there are also freshwater swamp forests such as those in Liguasan Marsh and Bulusan Marsh in Cotabato. They have low trees, patches of shrubs, and water grasses. Freshwater swamp forests are a special type of primary forests.

2. Grasslands

Only a few grasslands in the Philippines are natural formations; an example is the one on top of Mt. Pulag in Mountain Province. It rests above the mountain’s tree line. The uppermost 500 meters of Mt. Apo is also covered with rough and rocky grassland. The rest are the result of repeated destruction of forests. Such is the case of the grassland found in Mt. Malindang which resulted from years of logging and slash-and-burn farming. The dominant vegetation is grasslands in the Philippines consists of Cogon and Talahib both of which need abundant sunlight and moderate amount of moisture. Animal life in grasslands commonly includes snakes, lizards, rats, birds, and insects.

3. Coastal Zones

Because the Philippines is made up of 7107 islands, it has a very extensive coastline. Coastal zone refers to the strip of land at the edge of the sea or lake, including both the exposed and submerged portions. Along the coastal zone are mangrove forests, beaches, tidal flats, areas covered with sea grasses and coral reefs are among the richest. For example, the dominant vegetation in mangroves is bakawan; other plants include those locally called nipa, tangal, and busain. On these trees live many kinds of birds, lizards, snails and insects. And in the water beneath the trees, different kinds of fish, shrimps, crabs and mollusks abound.

B. Man-made Ecosystems

As the name implies, these are ecosystems built and maintained by people by people. They include agricultural ecosystems, fishponds, and urban ecosystems.

Examples of agricultural ecosystems are croplands (planted to rice, sugarcane, etc.) and plantations or orchards (planted to banana, coconut, etc.).

In the Philippines, two types of fishponds have proven to be lucrative to the owners but have negative impacts on the natural environment. These are: extensive fishponds converted from coastal mangrove forests and extensive fishpens that practically cover entire lakes, as in the case of Sampaloc Lake and Laguna de Bay, both in Laguna.

Examples of urban ecosystems are parks, greenbelts, subdivisions, and other development projects constructed for human use.

Most students of biology classify ecosystems into natural and man-made ones. Some, however, use the terms controlled (man-made) and uncontrolled (natural) ecosystems. Still others prefer the terms managed (man-made) and unmanaged (natural) ecosystems. However, some ecosystems are both natural and managed; these are natural parks, national parks, wildlife sanctuaries, and others that fall under the so-called National Integrated Protected Area System (NIPAS). These examples are defined by the Department of Environment and Natural Resources as follows:

1. Natural Park is a relatively large area not materially altered by human activity where extractive resource uses are not allowed and maintained to protect outstanding natural and scenic areas of national and international significance for scientific, educational and recreational use. This include Mt. Apo Natural Park, Northern Sierra Madre Natural Park and Mt. Kanlaon Natural Park.

2. National Park refers to a forest reservation essentially of natural wilderness character which has been withdrawn from settlement, occupancy or any form of exploitation except in conformity with approved management plan and set aside as such exclusively to conserve the area or preserve the scenery, the natural and historic objects, wild animals and plants therein, and to provide enjoyment of these features in such areas. Mt. Malindang National Park, Quezon National Park, and Tubataha Reef National Marine Park are some examples.

3. Wildlife sanctuary comprises an area which assures the natural conditions necessary to protect nationally significant species, groups of species, biotic communities or physical features of the environment where these may require specific human manipulation for their perpetuation. Some of the wildlife sanctuaries in the Philippines are Taft Forest Wildlife Sanctuary of Samar and Agusan Marsh in Mindanao.