In the 14th century, many water tanks were destroyed by military invaders. By the 16th century, much of the island's storage tank system had fallen into disrepair. But the Sri Lankan people were left with the agricultural skills that enabled them to rebuild the island's food production system, which gradually evolved into hill farming on terraced fields or lowland farming.
In the early 19th century, coffee plantations began to appear. Thus began the era of modern Sri Lankan agriculture, modeled after commercial plantations. The primary goal of the modern system, the generation of financial profit from the world market economy, differed from the goal of the traditional system, food sufficiency for the island's inhabitants. Tractors took on the energy role of water buffalo as a principal production input on plantations, and many defunct irrigation water tanks were refurbished for commercial use.
The water buffalo is also valued by Sri Lankan farmers because it is adapted to marsh conditions, and actually requires considerable time immersed in water or mud. Many Sri Lankan farmers deepen swamps or excavate portions of rice fields to create buffalo wallows. When the rice fields dry out during the harvest season, temporarily eliminating a habitat for various forms of aquatic life, the wallows remain moist all year. Wallows serve as "drought sanctuaries" for aquatic life forms that recolonize rice fields via annual floods.
Sri Lankan farming communities benefit significantly from the fish that survive the dry season in rivers, lakes, and wallows. When the rains resume, the surviving fish migrate up waterways to breed and mature in rice fields during the growing season. When the water recedes at rice harvest, many fish remain trapped in the pools and are handily caught.
Among the aquatic creatures to migrate upstream annually are insectivorous fish, including those which feed upon the malaria vector, the Anopheles culicifaices mosquito. While the drought sanctuaries are liable to serve as breeding grounds for the malaria vector, their presence reduces the distance fish must migrate, enhancing the potential for rice fields to be colonized by these fish. It is thus incumbent upon local community members not to remove all the fish that devour malaria mosquitoes.
The risk of ecological imbalance from overfishing drought sanctuaries is real. The fate of two other creatures in the Sri Lankan agroecosystem is more secure. Farmers welcome and respect Pytas mucosus, the non-venomous rat snake, and the lizard Varanus salavator. The rat snake feeds on grain-eating rodents, but needs a dense thicket for raising its young. The lizard Varanus salavator requires a similar breeding habitat, which is provided by well-maintained drought sanctuaries. The lizard eats poisonous snakes and crabs that inhabit lowland rice fields and burrow into rice bunds, weakening them.
The value of buffalo wallows to Sri Lankan agriculture is clear, yet one more example of their value is noteworthy. Roof thatch in Sri Lanka is often made from woven coconut leaves. Green coconut leaves are pliable and easy to weave, but removing them reduces nut production. So, farmers soak the dry and brittle leaves, often in buffalo wallows. For people who cannot readily purchase roofing materials, the presence of buffalo wallows in which to soak coconut leaves is an asset.
When tractors replace water buffaloes in Sri Lanka, the need for farmers to maintain buffalo wallows is decreased, and the beneficial effects of the wallows are lost. Is this the necessary tradeoff in the course of agricultural modernization? Apparently so, if our perspective on how modern farming systems relate to larger ecological phenomena is narrow.
If the people involved in decision-making about agricultural development value sustainable food production systems, they should consider how modern farming practices relate to larger ecological phenomena. Issues such as crop yield, soil quality, energy costs, biological diversity, economic viability, and the interrelationships of these and other issues are equally important. When a water buffalo is removed from its wallow, does the wallow become just another pool of water? What then happens to the fish, snakes, and lizards, not to mention the people who sleep beneath coconut leaf thatch? Perhaps the Pitta bird knows.