Preface

Summary

I recall speculating years ago with the distinguished Russian scholar, Victor Kovda, at dinner in his Moscow apartment, about the productivity of the currently impoverished vegetation surrounding the modern city of Tblisi in Soviet Georgia. I had seen in a museum in Tblisi an ancient oaken cart with wheels fashioned of single disks of oak cut from the end of a log fully 4 feet in diameter. Large oak trees or forests of any description do not exist in the region now. Kovda guessed that the current productivity of the region, measured as ecologists would measure it as “primary production”, is 1% of what it once was. The cause was deforestation followed by the grazing of goats, sheep, cattle, and, later, over much of the land, by tillage, all of which contributed to the erosion of a thin soil.

Tblisi, a landscape that has sustained human occupation from time immemorial, is but one example of the cumulative effects of long-term human activities on the capacity of the landscape for sustaining life. The conference that was the basis for this book emerged from many years of puzzlement over how ecologists address the human-caused transitions that now dominate plant and animal communities globally. For many ecologists, perhaps most, the answer seems to be to focus on some of the more fascinating aspects of the evolution and extinction of species. But human effects and disturbance reach much farther than to extinction alone.