Reduction in household size has led to a rapid rise in household numbers around the world and has posed serious challenges to biodiversity conservation, write Jianguo (Jack) Liu of MSU and Stanford colleagues Gretchen C. Daily, Paul R. Ehrlich and Gary W. Luck in the Jan. 12 advance online publication of the journal Nature. Biodiversity is threatened severely not only by increased numbers of households, but also by less efficient per capita consumption of natural resources, the researchers say. They cite examples that larger numbers of households require more use of natural resources for construction, and that smaller numbers of people per household use on average more energy and goods per person.
The decline in household size, say the authors, is due to factors such as a rising number of divorces, and more "empty nesters" because kids are leaving home. They note that around the world, the proportion of multi-generational households is declining steadily.
"Personal freedom and social choice may come at a huge environmental cost," says Liu, lead author for the Nature article. Liu studied the loss of panda habitat in China under a Faculty Early Career Development (CAREER) grant from the U.S. National Science Foundation (NSF), an independent federal agency that supports research in virtually all fields of science and engineering.
"Liu's work has provided insight into the ways people interact with their environment," says Tom Baerwald, senior science advisor in NSF's Division of Behavioral and Cognitive Sciences. "It's an excellent example of interdisciplinary inquiry that bridges the natural and social sciences."