he people who live on the isolated islands of the South Pacific have to be particularly careful in managing their natural resources: if these sources of food and shelter run out, they cannot simply move elsewhere.

For example, in the Solomon Islands, the people of Tikopia bury root vegetables and other foods to guard against poor harvests or other emergencies - like the category 5 cyclone that hit in 2003. They strictly monitor their population growth through traditional social systems that allow only the eldest son in each family to marry and have children. They stopped the practice of pig farming when they found that the animals were eating too many of their starchy food crops.