| The planet's wild creatures face a new
threat -- from yuppies, empty nesters, singletons and one parent families.
Biologists studying the pressure on the planet's dwindling biodiversity today
report on a new reason for alarm. Although the rate of growth in the human
population is decreasing, the number of individual households is exploding. Even
where populations have actually dwindled -- in some regions of New Zealand, for
instance -- the number of individual households has increased, bemuse of
divorce, career choice, smaller families and longer lifespans. Jianguo Liu of Michigan State University and colleagues from Stanford University in California re- port in Nature, in a paper published online in advance, that a greater number of individual house-holds, each containing on average fewer people, meant more pressure on natural resources. Towns and cities began to sprawl as new homes were built. Each household needed fuel to heat and light it; each household required its own plumbing, cooking and refrigeration. "In larger households, the efficiency of resource consumption will be a lot higher, because more people share things," Dr. Liu said. He and his colleagues looked at the population patterns of life in 141 countries, including 76 "hotspot" regions unusually rich in a variety of endemic wildlife. These hot spots included Australia, New Zealand, the US, Brazil, China, India, Kenya, and Italy. They found that between 1985 and 2000 in the "hotspot" parts of the globe, the annual 3.1% growth rate in the number of households was far higher than the population growth rate of 1.8%. "Had the average household' size remained at the 1985 level," the scientists report, "there would have been 155m fewer households in hotspot countries in 2000. Paradoxically, smaller households do not mean smaller homes. In Indian River county, Florida, the average area of a one-storey, single family house increased 33 % in the past three decades." Dr. Liu's work grew from the alarming discovery that the giant pandas living in China's Wolong reserve were more at risk now than they were when the reserve was first established. The local population had grown, but the total number of homes had increased more swiftly, to make greater inroads into the bamboo forests. Gretchen Daily of Stanford, one of the authors, said: "We all depend on open space and wild places, not just for peace of mind but for vital services such as crop pollination, water purification and climate stabilization. The alarming thing about this study is the finding that, if family groups continue to become smaller and smaller, we might continue losing biodiversity -- even if we get the aggregate human population size stabilised." |