More households lead to a higher demand for natural resources, even if the population stays the same This in turn exacerbates the threat to plants and animals, particularly in those areas of the world where many native species are at risk from human activity.
The study, published in this week's Nature, examines the size and number of households in 141 countries. The findings show that the growth in the number of households in 76 countries with biodiversity hotspots — including Australia, Brazil, India and the United States — was much higher than in non-hotspot countries.
"Increase in household numbers, often manifested as urban sprawl, and resultant higher per capita resource consumption in smaller households pose serious challenges to biodiversity conservation," the study concludes.
In a related news and views article, Nico Keilman of the University of Oslo, Norway, points out that most of the hotspot countries are in the developing world. He notes that between 1970 and 2000, the average number of occupants in households in less developed countries fell from 5.1 to 4.4.
© SciDev.Net 2003
Link to Nature research paper by J. Liu et al
Link to Nature news in views article by Nico Keilman
Photo credit: Caroline Jacoby