Skip to main content

Ecologist Urges Sharing Land with Other Species to Foster Biodiversity (web article)


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.

  • Eilat, Israel, “the Las Vegas of Israel.” When the Suez Canal was closed to Israel in 1950, the Israelis had to tear up most of a gorgeous coral reef offshore of Eilat to make a port. After peace came, the Israelis turned the area into a tourist trap. Today only one tiny bit of the reef exists . . . and they decided to build an underwater restaurant tucked inside the reef. Happily, researchers have discovered that antibiotics can preserve the lives of the coral pieces broken off by tourists; after drug treatment, the revitalized chunks are wired back onto the reef. “In an impossible place, a paradigm of reconciliation ecology,” said Rosenzweig.
  • The Turkey Point power station near Miami. To cool the hot effluent of the nuclear reactor,  Florida Power and Light gouged 80 miles of giant cooling canals into the adjacent land. Turns out, however, a rare species of saltwater crocodile soon moved into these warm channels and flourished. Instead of slaughtering these giant carnivores, the power company hired a permanent team of biologists to make the new habitat even more croc-friendly.
  • Hazelnuts instead of cotton seeds. A scientist has developed a hazelnut tree whose nuts produce four times more oil per acre than plants like cotton, corn, and flax. The hazeltree orchards do not need pesticides (result: more bugs, birds, and frogs); they keep their carbon dioxide contained since the trees themselves aren't harvested every year; and the trees' roots seek nutrients all year around, keeping harmful effluents from leeching into the water.

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