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Biodiversity Threat:
Many creatures will simply go to the wall without a concerted program
to breed and maintain captive populations of those in peril.

Why must we save animals
Colin Tudge calls for activist intervention to preserve biodiversity.

People who think of themselves as conservationists all agree on one thing: that as great a variety as possible of wild creatures should be able to live unharassed lives in pristine habitats. Most seem to agree, too – with only a few dissenting voices on what might reasonably be called the lunatic fringe – that the plight of human beings is at least as important as that of wild creatures, and that the conservation of wilderness must not harm local people and indeed should become a serious component of their economy. But then consensus stops and opinion polarizes into two, often warring camps, which we might call the pragmatists and the romantics.

The pragmatists see that ideals are vital, for without them we do not know what we are trying to achieve and have no spur to action. But the pragmatists accept that wild habitats must be tightly managed and that wild populations must be backed by animals bred intensively in captivity. The whole operation must increasingly be supported by science and the high technologies it generates – everything from genetics to quantified ecology and a whole panoply of reproductive physiology, including the freezing and transfer of embryos.

The romantics argue that to manage wilderness is to compromise its wildness. It is therefore pointless. They hold that captive breeding can achieve too little to be worthwhile and that if distasteful interventionist high-tech is what is needed, then the price is simply too high.

This dichotomy plays itself out in a hundred contexts. Should elephants in national parks be culled to contain their population, or should ‘nature’ be allowed to take its course? If the animals are culled, should the ivory be sold to finance conservation efforts and compensate local people, or do such sales perpetuate a pernicious trade? Should vets in zoos assist in embryo transfer – given that strict veterinary ethics proscribes intervention except when an animal is sick? Should zoos exist at all? The plight of the California Condor in the mid-1980s brought all this simmering to the boil, as scientists from the San Diego Zoo and Wildlife Park proposed to rescue the last few condors from the wild to breed them up. The National Audobon Society and others argued that the birds should be allowed to ‘die with dignity’. Fortunately (I would say) the pragmatists won, and captive-bred birds have now been released back into the wild.

As may already be obvious, I am a pragmatist, and have become more and more of one since I first started taking a serious interest in conservation in the 1950s. To be sure, all conservationists must be romantic to an extent – driven by emotion and spurred by optimism. But romanticism in this harsh world has to be hard-headed, or it merely becomes effete. Those who eschew the hands-on approach are being irresponsible; or at least have not appreciated the depth and scope of the problems.

The first of these – an issue that never disappears – is the rise of the human population. Second, there is the sheer mass of creatures that are faced by imminent extinction. And third – the point that almost always gets overlooked – is time scale. Politicians traditionally see the next 30 years as ‘the long term’, but on the biological scale a million years is an appropriate unit of time and the next thousand should be seen to be immediate.

The rise in human numbers is serious but not yet terrifying. If we take it seriously, and act accordingly, we have a reasonable chance of pulling through in a tolerable state, and bringing other animals along with us. Optimistically, we can point out that the percentage-rate of rise is falling and if it continues to fall as it has been doing it could reach zero around 2050. Then the population would be around 10-12 billion. If people average two children per fertile couple then the rate would eventually fall, since some people are infertile and some opt to be childless. For 500 to 1,000 years the decline in babies would be compensated for by an increase in human life span. But after 1,000 years or so population would start to fall and could in principle become as low as our descendants choose.

But as human numbers double the task of conservation will grow steadily more difficult for at least 500, probably 1,000 years. Huge changes in human demography are bound to take place within the lifetimes of millions of infants already on this earth. Even if the population change proves benign (a levelling out, followed later by slow decline) it will still be disruptive. While the world organizes itself to accommodate ten billion people, animals will surely be pushed even further to the sidelines.

This is the background reality. It would of course be best not only to keep animals alive but to do so in the wilderness in which they evolved. The trouble is that, even as things are, for many creatures this is no longer an option. It will become an option for fewer and fewer. The best we can do for wild creatures at present is to provide large well-protected national parks. There are two awesome realities, however, which non-biologists rarely consider.

First, individual animals – particularly big predators – may require huge areas. Each tiger, for example, is estimated to need 10 to 100 square kilometres, depending on the quality of the terrain. Secondly, for reasons of disease, genetics and simple accident, no population of wild animals can be considered secure unless it contains around 500 individuals. A thousand is probably more realistic. This means that a reserve that is smaller than, say, Yorkshire, probably cannot maintain a secure population of tigers. There is no wild-breeding population of 500 tigers, and there are precious few spare Yorkshires in Asia. Tigers are an extreme example but many creatures are similarly placed. At least 5,000 of India’s 20,000-or-so remaining elephants live in populations too small to be self-sustaining and are simply dying out. They only hang on because elephants are so long-lived. It is a world-wide problem. Even Yellowstone, the biggest park in the US outside Alaska, is believed too small to maintain a viable population of grizzly bears.

Yet this is the best of what happens at present; and still the problems queue up to be listed. Among them – little considered, but a constant threat – is war. In war, animals in reserves merely become easy meat. The last Père David’s Deer in China were slaughtered in the Emperor’s garden in the Boxer rebellion. Scimitar-Horned Oryx were annihilated in Chad in civil war in the 1960s. The Javan Rhino virtually disappeared from Vietnam in the French and American wars. If Mountain Gorillas survive the war in Rwanda it will be a miracle. And so on.

Then there is the imminent threat of climatic change. Animals have survived the Ice Ages and warm interglacials of the past few million years by migrating. In the caves of Yorkshire there are fossils both of hippos and of reindeer, each tracking the encroaching and retreating ice. The pending greenhouse effect could be just as dramatic. But present-day animals have nowhere to run.

For all these reasons and several more we need not only to protect as much of the remaining wilderness as possible but also to establish breeding populations outside, and preferably well away from, existing habitats. Both strategies are necessary: habitat protection and ex-situ captive breeding.

Can captive-breeding make a significant difference? The arithmetic, at first sight, is not promising. There could be 30 million species on this earth and, since most live in rapidly diminishing tropical forest, about half are probably endangered. Neither zoos nor other conservation facilities can breed 15 million species. So we have to acknowledge that bullish conservation in general and captive-breeding in particular cannot solve the problems of most animals.

But so what? Captive breeding is a tactic, and this one tactic cannot be expected to solve all problems. The technique is, however, suitable for terrestrial vertebrates – mammals, birds, reptiles and amphibia – and here the arithmetic becomes much more promising. In fact there are only 20,000 species of land vertebrate, some ten per cent of which are unlikely to be saved by habitat protection alone. That makes 2,000 candidate species for captive breeding; a number within the sights of present-day zoos. It is certainly achievable if the world takes captive breeding seriously. Those 2,000 species would include the Asian Elephant, all five rhino species, all the big cats and many smaller ones, most of the primates, and so on; in fact, most of the animals with which we most closely identify.

Although land vertebrates are the most obvious candidates, they are not the only ones. Cichlid fish from Lake Victoria and partula snails from the Society Islands are among a distinguished shortlist of invertebrates that live only in zoos.

Yet the detractors ask: ‘If animals are doomed to spend the rest of their time in zoos, what is the point?’ The point is that return to the wild is possible. It is intriguing that virtually all domestic animals have at various times returned to the wild – dogs, pigs, cats, mink, horses, donkeys, cattle, camels, budgerigars, parakeets – even though they have been bred in captivity expressly to reduce their wildness, sometimes for hundreds of generations. Return of wild creatures is not necessarily easy; yet it has been achieved with chimps, orangs, woolly monkeys, tamarins, lions, black-footed ferrets, Arabian Oryx. Of course, the list of successful returns is still short, but these are very early days in the history of hands-on conservation. Many plans to return captive animals to the wild are being held up only because it takes time to restore their habitats. Przewalksi’s Wild Horses, for example, are all set to return to Mongolia as soon as appropriate steppe is made ready.

This of course brings us to the final twist. Even if it is theoretically possible to return animals to their proper homes, how can we consider this if there is no wilderness to return them to? Well, things will surely get even worse for the next 500 years or so – but 500 years really is the short term. The hope is that as human numbers start to fall again, after 500 to 1,000 years, wilderness will become available – just as agricultural land is currently being ‘set aside’ in Europe.

In the end it all comes down to attitude. To set up programs of captive breeding and pro-active habitat protection with the hope of sustaining viable populations of animals for 500 to 1,000 years seems an awfully long shot. Yet many human institutions that were set up almost 1,000 years ago are still with us – like the great cathedrals of Europe. What were their chances of surviving so long? The alternative to hope is simply to give up.

Nobody supposes that active intervention with captive breeding is ideal. But it is necessary. And if we take conservation – or anything else in life – seriously then what is necessary must be done.

Colin Tudge’s books, Last Animals at the Zoo and The Day Before Yesterday are available as paperbacks from Oxford University Press and Pimlico respectively.

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