Death and Life in a Great American City

In the 1990s two alarming statistics grabbed headlines: A study conducted by a prisoners' study group found that 75 percent of the people in upstate New York prisons came from seven New York City neighborhoods. An examination of mortality data revealed that men in one of those seven neighborhoods Harlem had less chance of living to age 65 than did men in Bangladesh, arguably one of the poorest countries in the world. In fact, the seven neighborhoods identified in the study reported the highest rates of a long list of health problems, including AIDS, violence, infant mortality, drug addiction, tuberculosis, and asthma. The concentration of disease in specific places called for new kinds of analysis. The researchers who began to tackle these issues borrowed heavily from ecologists, who have a long tradition of examining the setting within which given problems arise. I offer a single example. In 1993 it became clear to a group of ecologists in Alaska that the numbers of sea otters had dropped precipitously [1]. They began to examine this problem by closely observing not just otters but the entire ecosystem of the Alaskan coast. They found that a shortage of sea lions had left killer whales without enough to eat, and the whales had begun to eat the otters. As the otter population fell, other populations were altered as well: the numbers of sea urchins, a favorite otter meal, went up; but the kelp forests, which fed sea urchins, went down. As the kelp became scarce, the other creatures that depended on it began to disappear. Because of the central role of the sea otters in all these changes, the sea otters were recognized as a population of the Alaska coast. In examining the problem of excess mortality in a small number of New York City neighborhoods, human ecologists began to look for the keystone populations and processes that were driving this emerging pattern of disease.