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March 22, 2004

Ecologist Urges Sharing Land with Other Species to Foster Biodiversity

Humankind's Best Chance to Preserve Other Forms of Life

Michael Rosenzweig, professor of Ecology and Evolutionary Biology at the University of Arizona in Tucson and a member of the National Academy of Sciences, spoke at the School on March 22 about Reconciliation Ecology: Having Our Land and Sharing It, Too. Reconciliation ecology refers to designing new habitats for other species in the midst of where people live and work. He held out the cheerful prospect of preserving biodiversity at low cost.

Rosenzweig pointed out that although human encroachment has traditionally been considered the chief threat to biodiversity, the notion that the world must be either “holy” or “profane,” either pristine wilderness or vandalized trashscape, is not true.

Further, he argued that this holy/profane assumption drives a wedge between people and nature. “I contend that if you separate people from nature,” he said, “they will forget about nature and become afraid of it.”

To speciate properly, an ecosystem must first of all have some area—“there's no such thing as a miniature tropical rainforest”— but if the world's allotment of pristine land is going to continue shrinking, what can be done?

Our only chance to foster biodiversity, Rosenzweig argued, is to make our backyards, and even the areas around sewer systems and nuclear power plants, more hospitable to other species.

He cited some encouraging examples of reconciliation ecology.

Rosenzweig looks forward to the day when city dwellers will come to ecologists and say, “I'd like some Gambel's quail, with a smattering of white-throated sparrows and flycatchers in my yard.” The ecologist would then answer, “Well then, do this to your garden and this to your front yard.”

He noted that Gambel's quail, for instance, are now thriving in many parts of Tucson since his team discovered that this species only requires a 10 percent cover of desert scrub before it will return to the city. Then, tantalizingly, he asked, “What can the citizens of Baltimore do to entice the Oriole back?” --Rod Graham

Public Affairs Media Contacts for the Johns Hopkins Bloomberg School of Public Health: Tim Parsons or Kenna Brigham at 410-955-6878 or