Prithiviraj "Pruthu" Fernando, a wiry, bespectacled biologist, was visiting his home in Colombo, Sri Lanka, for a much-anticipated Christmas vacation in 2004 when one of his friends who lived by the shore called him and said something strange had happened to the sea. At first, he and most people in Sri Lanka—even eyewitnesses—thought it was a localized affair. Then, throughout the day, news came in of more and more destruction and more people injured or dead. Finally, perceiving the magnitude of the tsunami, Pruthu and his colleagues from the Centre for Conservation and Research (CCR) grabbed medical supplies and headed south to the most stricken area to do what they could for the victims.
Little has been written about the impact of a tsunami on the natural landscape. Pruthu had been working on elephant conservation at Yala National Park, a vast 242,000-acre reserve outside Colombo that is home to elephants, leopards, wild buffalo, chital deer, and rare and magnificent birds like the lesser adjutant stork and the Malabar pied hornbill. He had been told the park was completely destroyed, yet when he returned to work two weeks after the tsunami, he saw that the impact was surprisingly patchy.
Members of the Department of Wildlife Conservation asked Pruthu to help them assess the damage. They had decided that cleanup was a priority, but Pruthu saw a different need. A survey of the scientific literature had turned up no published accounts of how a natural ecosystem responds to a tsunami. Because a tsunami is a natural phenomenon, Pruthu persuaded the authorities to postpone clearing away debris after the December 26, 2004 event and instead take the opportunity to monitor how a natural coastal forest recovers from such a catastrophe.
On foot Pruthu and his team immediately began mapping the affected area and collecting information on the severity of the damage in the portion of the park closest to the sea, a sector known as Block I, where an area about 10 miles long had suffered the brunt of the tidal wave. Most of the coastal zone in Yala was protected by sand dunes rising over 25 feet. On the other hand, ocean waters had rushed into areas like lagoon outlets where there were natural or artificial breaks in the dunes. The flooded area totaled three square miles in 12 different segments of the park, and salt water had poured into four freshwater ponds, or "tanks" (man-made water reservoirs up to several miles wide that were created by Sri Lankan kings in the 12th century). The force of the wave, the inundation of salt water, and the deposition of sand had heavily damaged the vegetation of Block I. Most of the grasses and herbs that had been drowned in salt water perished. Trees and bushes, by contrast, were most affected not by the salt water but by the tremendous force of the wave. Fortunately, the vegetation began to recover almost immediately, except for trees that had been completely uprooted.