Conservation, ecosystem use and
J.L. Gardiner and N.C. Perala-Gardiner
Man has lost the capacity to foresee and to forestall. He will end by destroying the earth.
This chapter attempts a holistic examination of the factors influencing river conservation globally, drawing on examples from the United Kingdom (UK) and the United States of America (USA). Subsequent chapters focus on specific issues in different countries. John Muir reflected that one could not examine anything without finding that it is attached to the rest of the universe, and Noel Hynes confirmed the need for holism in river conservation, because the river corridor reflects, sooner or later, the health of the catchment (Hynes, 1985). It is land use which determines the quality and quantity of the water environment. So, to put river conservation into a practical context, we may ask, ‘How well are we doing with our husbandry of the land and its wildlife, with nature conservation as a whole?’
The fossil record suggests that 95% of all the species that ever lived are extinct, with the average life span of a mammal species being about one million years (Pettifer, 1997). By contrast, although there may be some 13 million species on earth, with extraordinary diversity such as 473 tree species in a single hectare (Ecuador), and no less than 1200 species of beetle on a single tree (Panama), extinction rates in the past century show a species life span now averaging only 10000 years. A reduction to between 100 and 1000 years is currently threatened, so that extinction rates are 40 times greater than the past average ‘natural’ level for mammals and a staggering 1000 times for birds (Pettifer, 1997); an estimated 40 to 100 species become extinct every day (Owen and Chiras, 1995).
By contrast to this loss of species, the world’s human population doubled to two billion in the 100 years from 1830 to 1930, doubled again to four billion in the 44 years to 1974 and passed six billion in the next 25 years (during October 1999 – see Davies et al., Introduction to this volume). The present global erosion of 24 billion tonnes of topsoil per year will amount over a decade to
Global Perspectives on River Conservation: Science. Policy and Practice. Edited by P.J. Boon, B.R. Davies and G.E. Petts. © 2000 John Wiley & Sons Ltd.