Butterfield Jody - Holistic management a new framework for decision making

In addition to the works cited within the text of this book, a number of other resources were utilized in preparing the manuscript, many of which are listed here for the reader who wishes to pursue the various subjects in greater depth. Additional background information is also provided on some of the topics raised.

CHAPTER 1. CHANGING THE WAY WE MAKE DECISIONS

In the last few decades advanced radiocarbon dating techniques have begun to show that the majority of the worlds large mammal species became extinct relatively recently and that their disappearance strongly coincides with the arrival of skilled human hunters. Though mammals had been the dominant animals in terrestrial environments for over 70 million years, the majority of the larger speciesthose weighing at least 100 pounds (44 kg)suddenly became extinct at the very end of the Pleistocene, from 10,000 to 35,000 years ago, depending on the continent.

All continents except Antarctica were affected, the Americas and Australia to a much greater degree than Africa and Asia. In North America 74 percent of the large mammal genera disappeared, possibly within a few centuries. In South America 79 percent of the genera disappeared in an equally short time, and in Australia 86 percent became extinct over a slightly longer period.

Geoscientist Paul Martin (University of Arizona) has developed a theory called the blitzkrieg hypothesis, the central tenet of which is that the extinctions occurred within a few hundred years of the first arrival of humans in any one place. He and other proponents of the theory suggest that the large mammals, as well as large flightless birds, were easy prey to early humans because they did not recognize humans as predators. To back his claims Martin points out that the extinctions occurred at greater intensity on continents of human invasion than on those of human origin. In Africa, where humans evolved for millions of years with large mammals, the extinctions had been minimal (19 percent), compared with the tremendous losses in the Americas, which were colonized by highly advanced hunting societies at the peak of their powers.

The idea that people wiped out the great animals within a few hundred years of arriving on the scene does pose a problem: there is no archaeological evidence, other than in New Zealandand even that was within the last 1,000 yearsthat humans systematically slaughtered the biggest animals. Maori butchering sites have been found where between 30,000 and 90,000 moa were killed. Analysis of these sites by modern-day archaeologists suggests that the wastage of meat was enormous. Entire moa legs have been found baked in ovens that were never opened. Whole bodies were frequently left to rot.

In Australia there is no sign of hunting at all, despite the fact that Aborigines were hunters. Indeed, not until the recent excavation of a site near Cuddie Springs was there unequivocal evidence that put people and the large mammals in the same place at the same time.

Some scientists still attribute the mass extinctions in Australia and the Americas to climatic changes, most notably the last ice age. However, in North America the large mammals persisted another 20,000 years after the ice had retreated to the poles; in Australia, almost all the large mammals appear to have vanished 15,000 years before the ice age reached its maximum. Even so, the last ice age was only one of seventeen that had occurred over a 2-million-year period, and none of the others had triggered such a rash of extinctions.

I am inclined to believe that our earlier ancestors of 10,000 or more years ago played a critical role in the late Pleistocene extinctionsboth through overkill and through the dramatic changes they produced through their burning. There is considerable evidence that a much greater proportion of the pre-human arrival vegetation was fire sensitive following millions of years of coevolution (of plants, soils, and large mammals). The burning of fire-sensitive vegetation on the scale early humans did alone probably would have produced enough of a change to cause major extinctions, even if over-hunting were not a factor. One simply cannot change a continent from largely fire-sensitive vegetation to fire-dependent vegetation (as the pollen record shows, for instance, in Australia) without causing massive disruption to animal populations. Any prey population stressed by environmental deterioration is more susceptible to predation, which human hunters would have exploited.