Editor's Note: Ecologists normally think of evolution as independent of human influences. But people have been around for at least 2 million years, long enough to have influenced not only the landscape but evolution itself.

Naveh, a landscape ecologist, shows how long habitation of the Mediterranean Basin has affected both species and the structure of the communities of this region. The vegetation of the basin is both unique in having evolved over many thousands of years with dense human populations and, strangely, common to the point of illustrating the central principle of impoverishment.

The story is fascinating but not elevating: the human role has been persistent, unrelieved, continuous pressure toward impoverishment. The evolutionary response has been, not surprisingly, adaptation in the pattern now so familiar in these pages. Where we started on this path is obscure, buried in geological history hundreds of thousands of years back and interpretable in more recent times only from such fragmentary documents as the records of the rain of pollen left in special places such as bogs.

Naveh brings a lifetime of research and intimate knowlege of the region to bear on the history and development of the Mediterranean vegetation.