THE KINGDOM OF RARITIES

The World Wildlife Fund’s chief scientist examines the ecological impact of rare species in shaping the Earth's environment.

In 1988, Dinerstein (Tigerland and Other Unintended Destinations, 2007, etc.) was observing extremely rare one-horned rhinos in India when his attention was drawn to the large communal dung piles that they create. Islands of trees had been created from the fruit seeds that were contained in them. This observation led him to consider the possibility that “ecological impact does not always reflect numerical abundance.” The importance of preserving species diversity is recognized as essential to the maintenance of dynamic ecological balance, but not necessarily the historical evolutionary role of rare species. “[R]obins, rats, and roaches may account for 90 to 95 percent of all individuals on earth,” writes the author, but astonishingly, “as much as 75 percent of all species on Earth may be drawn from the ranks of the rare.” The author makes a subtle distinction between absolute numerical rarity and the rarity of habitats. For example, a species abundant in a small number of specific geographical locations may become extinct because of environmental shifts such as climate change. Trees in the Amazon rain forest may have a large range but, unlike more northerly trees that cluster, be spread out as individuals. A single gigantic tree may “create a three-dimensional stage for millions of smaller organisms and…hold more ant species than are found in the entire British Isles.” Throughout this intriguing book, Dinerstein covers a wide range of topics, including how myths about the supposed medicinal effect of rhino horns has created a lucrative illegal market that threatens them with extinction and why long-lived large animals with few predators but low reproductive rates are especially vulnerable.

An illuminating perspective on the complexity of life.