Reading Passage 1
You should spend about 20 minutes on Questions 1–13, which are based on the passage below.
The Sundarbans: a forest between land and sea
Where the Ganges, Brahmaputra and Meghna rivers meet the Bay of Bengal, they form one of the largest river deltas on Earth. Spread across this low, waterlogged land is the Sundarbans, the biggest continuous mangrove forest on the planet. It covers around 10,000 square kilometres, of which roughly sixty per cent lies in Bangladesh and the remainder in neighbouring India. The forest is neither entirely land nor entirely sea. Twice each day the tide pushes salt water deep among the trees, and twice each day it draws back, exposing banks of soft grey mud threaded with hundreds of narrow channels. This constant movement of water shapes every form of life that manages to survive here.
Very few trees can live with their roots in salt water, yet the mangroves of the Sundarbans have found several ways to do so. The sundari tree, which may have given the forest its name, sends thin woody spikes upwards out of the mud. These structures, known as pneumatophores, act like snorkels, allowing the roots to take in air even when the soil beneath is completely without oxygen. Salt presents a second problem. Some mangroves cope by moving unwanted salt into their oldest leaves, which are then dropped from the tree; others force salt out through tiny glands on the surface of the leaf, where it dries into pale crystals. A third strategy concerns reproduction: rather than releasing seeds that would simply be washed away, many mangroves allow their seeds to germinate while still attached to the parent, producing young plants that drop into the mud already able to take root.
The forest shelters an extraordinary range of animals. It is one of the last homes of the Royal Bengal tiger, a population famous for its willingness to swim between islands and, occasionally, to hunt human beings. Spotted deer and wild boar move through the drier patches, while the muddy creeks hide estuarine crocodiles and, in the more open water, rare river dolphins. Smaller predators such as the fishing cat hunt along the banks, and above them the branches are alive with kingfishers, eagles and herons. Because the landscape shifts with every tide, the animals that live here must be equally adaptable, moving with the water rather than against it.
People, too, depend on the Sundarbans. Each year, groups of honey collectors known locally as mawali enter the forest to gather wild honey from the hives that hang among the branches. Fishermen work the channels, and others cut wood or gather leaves for thatch. Many of these people share a belief in Bonbibi, a guardian spirit of the forest, and will not enter without first asking her protection — a tradition that reflects just how dangerous the work can be. Attacks on honey collectors and fishermen are not unknown, and the risk of meeting a tiger is a constant part of their working lives.
The value of the forest reaches far beyond the people who live at its edge. When cyclones sweep in from the Bay of Bengal, the dense wall of mangroves acts as a buffer, slowing the wind and breaking the force of the storm surge before it reaches the villages and farmland inland. In 2007, when Cyclone Sidr struck the coast, areas protected by healthy mangroves suffered noticeably less damage than those that had been cleared. Mangroves are also remarkably efficient at removing carbon dioxide from the atmosphere and locking it away in their waterlogged soils, where it may remain for centuries. Scientists sometimes call this stored carbon ‘blue carbon’, and it makes the forest a valuable ally in the effort to slow climate change.
The Sundarbans is nonetheless under growing pressure. Sea levels are slowly rising, pushing salt water further inland and making the soil too salty for some species. Upstream, dams and other structures reduce the flow of the fresh water and silt that the delta needs in order to renew itself. Poaching removes tigers and deer, while illegal logging strips away the trees faster than they can grow back. Each of these threats is serious on its own; together they place the whole ecosystem at risk.
In response, both Bangladesh and India have given large parts of the forest protected status, and much of it is now recognised internationally for its importance to wildlife. Tigers are counted using hidden cameras, patrol teams try to prevent illegal hunting, and villagers are increasingly offered other ways of earning a living so that they depend less on the forest itself. Protecting this shifting landscape, biologists argue, means protecting not only its tigers and its trees but the millions of people whose safety, in the end, depends on it.