Everything is interconnected

How could rising infrastructure construction in Metro Manila influence the price of durian in Mindanao? How did a program meant to raise protein availability in our countryside inadvertently harm production of our main carbohydrate source? Why might the biological cleanup of the Pasig River by introducing “beneficial” microorganisms not be such a good idea? How has rising demand for wood and timber contributed to the slow crumbling of the world-renowned Banaue rice terraces?

These are but a few questions that illustrate the often unseen, seemingly unrelated and complex links that exist within our environment. The first was an examination question once used in an environmental sciences and management course by a professor friend. What indeed does construction in Metro Manila have to do with durian prices in Mindanao? The answer has to do with the distant but real relationships that lie in the food and product chains. Increased construction in the city translates to higher demand for cement, production of which requires limestone. Limestone lines the Mindanao caves that are the common habitat of bats. Cave nectar bats (Eonycteris spelaea) are known to be the only effective pollinators for durian; Malaysians reportedly even have a local saying that goes: “No bats, no durians.” When limestone in caves is gathered for use in the manufacture of cement, the natural habitat of bats is disrupted, thereby affecting their numbers. With the reduced pollination of durian trees that results, productivity of durian fruit goes down, leading to lower supply and higher prices on the market.

In the 1980s, the government introduced and promoted golden snails (kuhol) originating from Florida, as an alternative source of protein for rural communities, and also as possible export product for the European markets, where escargot fetches high prices. But the introduction of this alien animal species proved environmentally disastrous. Originally meant to be cultured, the golden snails that escaped or were discarded reproduced rapidly and spread through waterways and irrigation canals. They found an ideal habitat in the rice fields, invading
them and feeding on newly transplanted rice plants. With few natural enemies to curb their population, coupled with their rapid rate of reproduction — females lay egg masses of up to 500 eggs once a week — the snails became a serious pest in rice fields in the Philippines, capable of destroying entire rice crops.

This is the same reason that led scientists at the Department of Environment and Natural Resources to caution against the proposed introduction of supposedly beneficial microorganisms as a biological solution to clean up the Pasig River in the 1990s. While the microorganisms to be introduced would supposedly feed on the pollutants that have killed life in the river, there’s no telling whether these alien microbes would turn into yet another invasive alien species that could lead to unexpected environmental disaster. Still, these proposals have persistently cropped up over the years. Indeed, alien invasive species are the object of great caution worldwide precisely because instances of environmental disasters have arisen from how alien species have upset the natural ecological equilibrium in places where they were artificially introduced.

Up in Ifugao province, the depletion of forests high up in the mountains above the famous Banaue rice terraces is at least partly blamed for the invasion of giant earthworms now seen as the greatest menace to these terraces. The earthworms that grow up to 18 inches long and half an inch thick have burrowed into the terrace walls and weakened them to the point of crumbling under strong rainfall. Terraces have thus collapsed in many parts of what had been termed the “eighth wonder of the world.”

There are many more examples close to home illustrating the so-called “butterfly effect,” whereby the flapping of a butterfly’s wings in the Amazon could ultimately cause a hurricane in Europe due to a complex chain of interconnected events in nature. The message for all of us should be clear: Our world is fragile, and we would all do well to tread carefully in it.

cielito.habito@gmail.com