Definition of an Ecosystem
An ecosystem is a collection of different organisms and the environment in which they live. Ecosystems can vary greatly in size & complexity. Some examples of small ecosystems are tropical fish tank, tidal pools, a home garden or pond, or the stomach of an individual cow.
Larger ecosystems would include mangrove estuaries, lakes & rivers, agricultural fields, rainforests & of course coral reefs. Two of the most well known ecosystems on Earth are The Amazon Rainforest & The Great Barrier Reef. One of the most recent ecosystems discovered by science are smokers (volcanic vents on the sea bed). Landscape-scale ecosystems encompass larger regions, and may include different regions of land and both freshwater & marine communities.
Ultimately, all life on Earth and the physical environment in which it lives, is part of one great planetary ecosystem called a bioshere. Therefore it could be argued that the definition of a biosphere could be “An assortment of wide & varied ecosystems on a planetary scale”
Ecologists are scientists who study the relationships of organisms (ecosystem) with their environments (ecoregion). For example, depending on the specific interests of an ecologist, an ecoregion might be defined as the shoreline vegetation around a lake, or the entire lake itself, or the lake plus all the land around it. Because all of these units consist of organisms and their environment, they can properly be considered to be ecosystems within ecoregions.
The raw materials of an ecosystem
All ecosystems have a few basic characteristics in common. They use energy (usually provided by sunlight) to build complex chemical compounds out of simple materials. At the level of plants, for example, chlorophyl acts on carbon dioxide and water using the energy of sunlight to produce complex carbohydrates, such as starches & sugars (this process is known as photosynthesis). As plants & their products, whether leaves, nectar or fruits are consumed by other organisms, these complex substances produced at plant level & the energy by which they were created, are passed ever upward through the food chain & often culminating in man himself. It is therefore of prime importance for us to understand this process & to apply this knowledge to the continuation of such resources.
The flow of energy in an ecosystem is bidirectional & not always consumed by higher levels of organisms. Take for example a decaying tree, whilst it lived it produced leaves & fruit, yet as it decays & it’s tissues break down, it’s compounds & nutrients are often absorbed by fungi & bacteria. As a result, the process starts all over again. Even the energy & food produced by a living tree for example, not only passes to higher life forms, but also to insects & bugs which feed on the leaves & bark. Each level of a food chain contains more energy than the levels below it & consiquently each higher life form also requires more energy with which to function.
Man has, over hundreds of years, made several grave mistakes by the introduction of foreign species into various ecosystems throughout the world. The result of which has been, the destruction of habitat, the endangerment & often extinction of species and ultimately the collapse of many delicate ecosystems.
One of the greatest challenges facing humans and their civilization is to develop a complete understanding of the fundamentals of ecosystem management, how they are structured, how they function & how they should be maintained for the sustained benefit of future generations.
Ecoregions of the Philippines
The Philippine Islands being volcanic in origin, are in geological terms at least, extremely young when compared to the Asian continent. Because the Philippines & Mainland Asia were never connected via land bridges, any flora and fauna had to cross ocean straits to reach the Philippine Islands and as such, in many cases, have evolved into totally separate species which are endemic to the Philippines.
The Philippine Islands are part of the Indomalaya ecozone, and its flora and fauna are mostly derived from tropical Asia. Botanically, the Philippines are part of Malesia, a floristic province that includes the Malay Peninsula, Indonesia, and New Guinea. Most of the Malesian flora is derived from tropical Asia, including the dipterocarps, which are the characteristic tree of the Philippine forests. Elements of the Antarctic flora, which originated in the ancient southern hemisphere supercontinent of Gondwana, are also present, including ancient conifers like podocarps (Podocarpus, Nageia, Sundacarpus) and araucarias (Agathis).
The ecoregions of the Philippines were created primarily by the sea levels during the Ice Ages, which were 120 meters lower than at present, as billions of gallons of water were locked away in huge continental ice sheets in the northern hemisphere. This drop in sea level connected many presently separate islands into larger islands, which allowed for exchanges of flora and fauna.
Each group of islands that were linked by land bridges in the ice ages also constitutes a separate faunal region. The lack of a land bridge to the Asian continent prevented most of the Asian megafauna, including elephants, rhinoceros, tapirs, tigers, leopards, and gibbons, from reaching the Philippines, although they do inhabit the adjacent Indonesian islands of Sundaland, which were formerly linked to the Asian continent by lowered sea levels. As is the case with the rest of Asia, the Philippines also lacks the Marsupial species found in Australia & South America.
- Greater Luzon included Luzon, Catanduanes, Marinduque, Polillo, and several small islands.
- Greater Mindanao included Mindanao, Basilan, Bohol, Leyte, Samar, and adjacent small islands.
- Greater Palawan included Palawan, Balabac, Busuanga, Culion, Cuyo, and adjacent small islands.
- Greater Negros-Panay included Negros, Panay, Cebu, and Masbate.
- Greater Sulu included the most of the Sulu Archipelago, from Tawi Tawi to Jolo.
These formerly linked islands each constitute a separate ecoregion, as does Mindoro, Camiguin, Sibuyan, and Siquijor, which all remained separate from the rest.
The other main factor that defines the Philippine ecoregions is elevation; the high mountains of Luzon and Mindanao host distinct montane rain forest ecoregions. The mountains of Luzon are also home to the Luzon tropical pine forests.
Tropical and subtropical moist broadleaf forests
- Greater Negros-Panay rain forests
- Luzon montane rain forests
- Luzon rain forests
- Mindanao montane rain forests
- Mindanao-Eastern Visayas rain forests
- Mindoro rain forests
- Palawan rain forests
- South China Sea Islands (disputed between China, Malaysia, Philippines, Taiwan, Vietnam)
- Sulu Archipelago rain forests
Tropical and subtropical coniferous forests
- Luzon tropical pine forests
The Philippines provides a high environment of natural resources in areas such as agriculture, nature, and minerals. It has fertile lands, diverse flora and fauna, extensive coastlines, and particularly rich mineral deposits, due mainly to the volcanic origin of the Islands.
