The importance of biodiversity has to be put into perspective. Biodiversity is one human need amongst many. The instrumental use of biodiversity in the Amazon has to be balanced against other development needs of the Brazilian people.

How much biodiversity is being lost ?
It is argued that there is a massive loss of biodiversity, mainly caused by habitat destruction, of perhaps 50,000 species a year. The evidence for this is slender. Scientists use two ways to estimate extinction. The first is straightforward: count them. The second is by extrapolating loss of species by measuring the loss of different kinds of habitat.
A species is said to have become extinct if it has not been seen in the wild for over fifty years. On this basis, the International Union for the Conservation of Nature and Natural Resources (IUCN) has reported 593 extinct animal species (IUCN Red list of Threatened Animals 1994). Another study (in 1992) listed 384 vascular plants which have become extinct. This approach will miss many species–potentially thousands– which have never been described by science. In addition, this approach does not mean that a species is lost–for example the small wild cat (the guigna) weighing just five pounds, was recently trapped on an island off Chile for the first time in seventy years. (National Geographic October 1997).
Documented extinction of animals peaked in the 1930’s and since then has been running at around ten per decade. About 75 per cent of recorded extinction has occurred on islands, including almost all bird and mollusc extinction. Island species are far more vulnerable because they have a small, confined range and may not have evolved to deal with predators. They may also be better studied by scientists and are more likely to be missed. Very few extinctions have been recorded in continental tropical forest habitat, where mass extinctions are predicted to be occurring, although this may be partly due to the difficulty of demonstrating extinction.
The extrapolation method is based originally on measurements on islands, which related numbers of species to the size of island. These showed that, if one island is ten times the size of another, you would expect to find twice as many species. The converse also holds: if you reduce the size of a habitat to ten per cent of the original, 50 per cent of the species will remain. It is these mathematical models which are used to make the predictions of enormous loss of biodiversity.
How useful are these predictions? The simple answer is that we do not really know and more work is needed. The equations predict the number of species which will be found in an area of forest, not whether the species only exists there. In addition, forests are not uniform but contain areas of different levels of diversity. Vernon Heywood and Simon Stuart, who head the IUCN’s Plant and Species Conservation Program, recently noted that “there is currently little evidence of extinction at the rates predicted by some theoretical models”. This does not, of course, mean that there is no cause for concern but that the figures which are commonly presented should be treated with caution. If biodiversity hot-spots are protected, it may be that most of the biodiversity will be too.

Why is biodiversity important?
It is important for us to work out what value biodiversity has to us. In arguing for the preservation of biodiversity many writers say that nature has an intrinsic value beyond any potential uses it may hold for humanity. They believe that the human species should be equated with other species on an equal plane and that we should not be so arrogant as to think that we are at the top of a natural hierarchy. Others put forward an instrumentalists case. They argue that biodiversity should be preserved because it could have potential benefits for humanity in the form of as yet undiscovered drugs or foodstuffs. There are serious problems with both arguments.
First, the case that nature has an intrinsic value above and beyond meeting human needs. Nature has no intrinsic value. One can agree that there is no hierarchy in nature in evolutionary terms as all animals are on the same plane. But humans are unique in their ability to create society and have a right to be arrogant about their position from that perspective relative to other species. There are many reasons for this uniqueness, the most important is that we are the one species, that through creating society, has separated itself from nature. Humanity as a social entity is completely divorced from nature. The natural world in and of itself does not have any social capabilities. Unlike animals we do not just live in nature and respond to its dictates, we manipulate it. Although we are not alchemists–we cannot defy nature and conjure something out of nothing–our unique social development has been achieved through manipulating nature for our own particular needs. In so doing we have been able to transcend nature’s meagre gifts to us. Our manipulation of biodiversity is one aspect of this process. Only human beings are able to endow species with value, so biodiversity should be brought down from its pedestal and considered as one human need among many.
We may feel that we want to preserve certain aspects of the environment which enrich our lives. The preservation of tropical forests is felt to be important by most people who visit them. Certain species are important for aesthetic reasons. Other species may be of less immediate interest but their existence is of scientific and intellectual importance. We must be prepared to make distinctions and say that the tiger is more important to us than some species of tree slug, identical to another species except to an expert.
Once we have gained knowledge about a chemical derived from a species, which can be used to make a drug, we can synthesise the chemical artificially much more cheaply than we could extract it from the plant. From that point on, the plant loses a lot of value. Even a keystone species is only of value if the ecosystem which it supports is important to us.
The argument that biodiversity should be preserved because of its potential benefits for humanity is more complicated but equally problematic. Humanity is unique and indeed superior to nature as the only species capable of consciously intervening in nature and utilising it to serve its own needs and thereby allocating it value. It is therefore entirely rational to preserve biodiversity as a pool of resources which could be of potential benefit or value to humanity. The problem is that advocates of such an approach refuse to put the argument for potential benefits into the broader context of human needs. They focus almost entirely on the future potential benefits of biodiversity preservation and ignore the immediate needs of humanity in the here and now. In fact, attempts to preserve biodiversity in the Brazilian Amazon have often undermined the ability of humanity to meet its immediate needs.
Environmentalists’ demands for biosphere reserves, sustainable development programmes and nature parks and the general impact of the preservationist approach have prevented many industrial, mining and energy development programmes from being completed in the Brazilian Amazon. Potential benefits are just that–a potential–of unknown benefit to some known or even unknown need. Today we have plenty of real and immediate needs. There exist pressing social problems such as poverty which we know that we can solve with resources that we know exist and which we have at our immediate disposal. Brazil has a foreign debt of about US$150 billion and this is a major contributory factor to the misery experienced by its 43 million citizens who live below the poverty line. Brazil also has the Amazon, a source of fantastic wealth which could help end this misery. It is estimated that its timber supply is alone worth US$5 trillion. To this can be added the value of its huge stocks of minerals and its massive hydroelectric potential.
The question is how should the Amazon be utilised to serve the needs of the country which possesses its wealth? By focusing almost exclusively on a preservationist approach the resolution of such huge problems would be delayed and indeed may never arrive. The rational answer is a trade-off between the actual and the potential. A trade-off between known solutions to immediate problems and the future benefits of an unknown potential. If a mineral resource which could generate billions of dollars of foreign exchange to pay off the debt, is discovered in an area of potential biological wealth then the mine must be built. If a dam is planned for an area which is known to have genetic material to cure cancer or malaria and there are alternative sites for the dam, build it elsewhere. The immediate needs of first Brazilians and then humanity generally, should come before any potential benefits.
Many scientists calling for the preservation of biodiversity are not driven by rational calculations over the instrumental use of biodiversity. Much of their scare-mongering about the extent of loss of biodiversity and the problems of population pressure does not rely on a scientific and rational consideration of the benefits to Brazilians or humanity generally but on sentiment. Such sentiment will not only impede science but human development as a whole. Arguments about conservation, including those about loss of biodiversity, reflect a sentiment that says we no longer have much faith in the progress of human development. That lack of faith is reflected in the current idea that humans have already gone too far in developing the world and its resources. Most people are today concerned with putting the brakes on. Rather than looking for paths to make further developments in human progress the arguments for conservation now have the upper hand. The irrational, one-sided preservationist approach to the utilisation of biodiversity fits into this conservative, conservationist mood. We should reject it if we want human society to go forward and attempt to solve the real problems we are still confronted with in Amazonia and elsewhere.