by Tony Juniper
Much of this incredible variety is located in quite specific places with many species of plant and animal restricted to very small areas. Many of these places are islands like Jamaica or the Mascarenes where isolation has brought forth unique life forms through evolutionary processes working for millions of years to change the ancestral species that arrived there by chance.
What is less obvious are the many biological ‘islands’ scattered across the continents too. Rift valleys, volcanoes, mountain ranges, huge rivers and climatic differences have all conspired to isolate, in an evolutionary sense, different parts of the earth’s surface from neighbouring areas. The result is a mind-boggling assemblage of animals and plants, possibly the greatest single array of life seen during the whole of this planet’s billions of years of biological history.
Birds, parrots included, are generally speaking the best-documented group of animals. More is known about them than any other comparable creatures. For that reason, the International Council for Bird Preservation – now BirdLife International – decided in the late 1980s that a good way of working out where to focus their and others’ efforts in the pressing struggle to hang on to as many wildlife species as possible was to map out where the birds confined to particular small areas actually lived.
Researchers set out some simple criteria and began their gargantuan task. The intention was to map the distribution of all birds confined to a total range of less than 50,000 square kilometres; that is about equivalent to the size of Costa Rica, a little larger than Denmark or a bit smaller than West Virginia. After years of trawling through all the records and reports they could find, including manuscripts and reports from the early European explorations, they produced a new world map.31
Instead of countries and cities, this map showed with coloured dots, stripes and patches that set out where the birds with restricted ranges lived. The logic was simple. Given that birds are the best known life forms, mapping the places where the ones with restricted ranges dwelt should give clues as to where terrestrial evolutionary forces have been operating for millions of years in isolation. Since the unique biological conditions that had given rise to the birds (including many rare parrots) might have influenced the development of other species too, mapping the birds could in turn identify where everything else is most different: mammals, freshwater fish, plants, insects, reptiles and so on. If such centres of natural uniqueness were identified and protected, then perhaps it would be possible to save more of the earth’s natural diversity than if national parks and nature reserves were sited less systematically, or with less comprehensive information.
The research found that fully a quarter of the world’s bird species naturally occurred over areas of less than 50,000 square kilometres. Among them were 110 species of parrot, nearly a third of the whole family. The clusters of the restricted-range birds identified 218 places around the world where evolution had generated unique birds. And the locations of rare parrots, in common with the other birds, proved accurate signposts to rare plants and other life forms.
One such area was marked as a brown blob in the interior of north-east Brazil. It was labelled B46 – the caatinga. In this quiet corner of the globe the bird researchers found eleven species confined to there and nowhere else: six with ranges below the 50,000-square-kilometre limit and five more found slightly more widely but still only in the north-eastern drylands. Of the six that were strictly limited in their distribution to a total range of less than 50,000 square kilometres, one was only discovered while the mapping work was going on. This was the Caatinga Nighthawk (Chordeiles vielliardi), found in 1994 in just one locality on the banks of the São Francisco River. The others were the Pygmy Nightjar (Caprimulgus hirundinaceus), Tawny Piculet (Picumnus fulvescens), Red-shouldered Spinetail (Gyalophylax hellmayri) and two species of blue macaws, Spix’s and Lear’s. Four out of the six were on the cusp of extinction.
Until the 1990s the caatinga had from a biological point of view really been a forgotten corner of the world.32 It had been a place of gradual biological impoverishment for 400 years, but the process was slow and not very dramatic – certainly not the stuff of television news reports. The caatinga seemed to be a hot dry desert, not like the moist rainforests that teemed with colourful life. Predictably, few people gave it their attention. It was largely ignored. The outward appearance of a dry and unvarying wasteland was, however, misleading; the fact was that it had given rise to up to eleven of its own special birds. This suggested a long period of biological isolation and the prospect that other unique life forms might be found there too.
Eleven species may not sound like a lot given the millions of species that most likely exist today, but the birds were indicators. There are only about 10,000 species of bird and many of these are quite widespread. Indeed, the nearest place to Washington DC approaching a similar level of avian uniqueness to the caatinga is more than 1,500 kilometres away in the Caribbean, while the nearest such place to London is in the Canary Islands, some 2,500 kilometres distant, off the coast of Africa. And in the Canary Islands, there are only four unique birds.
At the same time as ornithologists began to put the caatinga on the world conservation map, there was growing interest in the place from botanists too. One programme was undertaken by the Royal Botanical Gardens at Kew in England working in collaboration with Brazilian scientists. Their initial findings revealed that the caatinga is a major evolutionary centre for plants containing many unique species and genera. The botanists’ preliminary investigations conducted during the middle of the 1990s showed that over 300 species and 18 genera of plants were confined to the caatinga and in danger of extinction. Many of those species were hardly known in terms of their potential to provide new drugs, industrial materials or crops.
The São Francisco River valley, like the islands of the Caribbean, had been subject to the effects of European colonisation for centuries. The occupation of the interior was at first not rapid. Indeed, in 1615, one hundred years after the Portuguese discovered Brazil, there were still only 3,000 Europeans living in that vast new territory. But one hundred years after that, their numbers were rising fast and the newcomers were already having a major impact on the land and the forests, including the dry north-east.
The river provided an incomparable route for colonial exploitation of the interior. Portuguese, Dutch and other adventurers were at first drawn inland from the coast by legends of emerald mountains and vast silver mines. Later travellers more realistically came in search of natives to enslave. In due course the colonial activities along the river became more settled: at its headwaters in Minas Gerais in the south, the São Francisco became an important artery for the mining economy, while its lower course was the scene of missionary activity. In its middle reaches around Juàzeiro it became a land that would draw its character from the herdsmen who settled there.
Towns developed on the sites of the old Indian settlements infiltrated by Jesuit missionaries. Large ranching estates emerged. In the remoteness of the interior, isolated from the more economically and culturally dynamic coastal estates and cities, a feudal land-use system evolved. Cut off from the rest of the country and abandoned to its fate, the remote north-east later became known as ‘the backlands’.
Separation from the civilisation at the coast, intense droughts and the unforgiving land bred determined survivors. Sinuous dark-skinned people with a rugged toughness came to characterise the hot dry interior. These mestizo people remained distinct from the men and women at the coast, where Africans pressed into service on the huge estates added to the blend of humankind that the colonial powers mixed there. The caatinga economy also spawned a unique kind of cowboy – the leather-clad vaqueiro. His special clothes, leather armour to protect against the vicious spines of the trees and cacti, are still worn there today.
The land gradually changed as people began to settle in the middle reaches of the São Francisco valley during the seventeenth century. The larger trees were felled to provide timber for buil
dings and boats, while cultivation was practised where some of the better soils lay – around Curaçá for example. The main focus, however, was on cattle and by the start of the eighteenth century there was already extensive ranching. To open land for grazing, the colonists used fire. Vast blazes were set on land parcelled out for the new estates, but of course the flames met no boundaries on the parched caatinga. The fragile forests were devastated.
The colonial administrators in north-east Brazil foresaw the threat to the long-term health of the caatinga and in 1713 decrees were issued to limit the burning. In this tinder-dry land no new law could on its own control the vast conflagrations; any fire was liable to quickly get out of control. And the native woodland was never able to recover from the burning because of the number of animals turned out to graze there.
More than a hundred years of intensive burning, logging and grazing had already preceded the early nineteenth-century passage by Spix and Martius. What had come to pass in the special creeks by then we can only guess at, but given the rare moisture they held, the presence of big timber trees and the potential for cultivation on their fine soils, it must be that their degradation was already well advanced by the time that Spix found the macaw that bears his name. Paul Roth believed that the wooded creeks once extended for 50 kilometres into the caatinga either side of the São Francisco River and occurred along a significant stretch of its middle reaches. By the time the last wild Spix was found in 1990, only two little patches remained.
Not only did the ecological impoverishment of the caatinga threaten wildlife, it undermined the human economy too. Even from the early days of settlement the region suffered cycles of economic boom and bust, in part caused by the vagaries of international commodity price fluctuations, but mainly because of severe droughts made worse by the gross environmental degradation inflicted on the land from the earliest times of colonisation.
During the twentieth century, efforts were made to stabilise and improve the lot of the region’s destitute people through large-scale ‘development’ projects. In the 1950s, the World Bank joined in. By then the valley of the São Francisco had land-use patterns typical of much of Brazil: large estates and plantations owned by rich landlords with the majority of the population living in extreme poverty as tenants, labourers and squatters. Rather than face these deep-seated social inequalities, the World Bank decided to target its main effort on harnessing the potential of what one of the country’s historians had called the ‘great highway of Brazilian civilisation’, the São Francisco River. The Bank would provide funding for energy and farming projects that had one thing in common – they depended on lots of water.
In 1974 the World Bank provided finance for the Sobradinho dam. The reservoir created above the barrage some 50 kilometres upstream from Juàzeiro and Petrolina flooded a large area of the São Francisco valley, including any potential habitat for Spix’s Macaw. Seventy thousand people were displaced too. Some of these dam refugees sold the little plots of land granted to them as part of a poorly conceived resettlement programme, thereby increasing the size of the already huge estates that dominated farming in the region. Others moved to a different part of the caatinga, or to the rainforests where they were forced to clear yet more land to feed themselves. Many of them finished up in the expanding favelas that had sprung up in Brazil’s cities.
The downstream effects were also dramatic. Because of changes to the river’s flow pattern, the World Bank was forced to make another US$65 million emergency loan for the construction of dykes and polders to protect the farms on the floodplain at the mouth of the river. Another 25,000 hectares of floodplain was also appropriated to establish five huge irrigation projects that claimed more of the land adjacent to the river and displaced another 10,000 families. Some attempts were made to help resettle them, but in the face of expanding irrigated sugar-cane production, most left the area or remained in extreme poverty where they were. So disastrous was the impact of the World Bank’s ‘development’ activities on the people of the caatinga that it led to the adoption of the Bank’s first official policy geared to the resettlement of people affected by its own projects.
The result of the transformations stimulated by the Bank’s investments as well as Brazil’s own farm policies was the gradual replacement of small-scale subsistence farming with capital-intensive irrigated agriculture directed to supplying export markets. Later on, the predations of oil and gas prospecting and mining would add to the impact of agriculture and hydropower.
These progressive steps towards the commercial exploitation of the caatinga would enrich a few but by and large they did not relieve the misery of the ordinary people. Thus were the natural ecosystems of the river valley liquidated in the name of development with little regard for their uniqueness or worldwide biological importance, and with very few benefits passed on to the people who were supposed to enjoy being ‘developed’.
On top of that, the World Bank loans used to pay for the dams were lumped into Brazil’s massive and growing debts to foreign banks and governments. This burden undermined the country’s economic stability for decades to come and led to policies that would in their turn further damage the environment as the country struggled to raise cash to pay off its creditors.33 The caatinga was left like a bombed city, the ecological equivalent of Hiroshima: utter destruction with the survivors hanging on in isolated groups here and there – in the Melância Creek, for example, where a few Spix’s Macaws sheltered.
By 1990 the creek was one of a few last fragments of caatinga that gave clues as to what the place had been like before the European colonists arrived. The indigenous people who spent 10,000 years of prehistory in the creeks had certainly made their mark too in burning the land, cutting trees and hunting game, but they had inflicted nothing like the profound impact of the foreign colonists.
Similar patterns of farming, energy and natural resources policy can be seen throughout the world. The main difference between what is taking place now and the impacts caused during the European colonial era is the scale and speed of change. Few people get a bird’s-eye view of such trends. One person who has is Mario Runco, an astronaut on space shuttle missions in 1991 and 1993. ‘Most people don’t get to set how widespread some of the environmental destruction is. From up there, you look around and see that it’s a worldwide rampage,’ he said. That rampage is driving extensive habitat loss and the extinction of species. It is certainly dramatic, but why should we be bothered? The process of extinction is after all a perfectly natural phenomenon.
It is, for example, estimated that only around 2 per cent of all the species that have ever existed are alive today. What is different now, however, compared to what appears to have happened under ‘normal’ circumstances in the past is the rate at which species are disappearing. Edward Wilson, the author of The Diversity of Life, one of the most authoritative accounts of the earth’s natural diversity, estimated in 1992 that in the tropical rainforests alone ‘the number of species doomed each year is 27,000. Each day it is 74, and each hour 3.’ Based on such projections and comparing them to the clues about natural extinctions that we have gleaned from the fossil record, Wilson concluded that human activities have accelerated the expected background rate of extinction by between 1,000 and 10,000 times. The great majority of informed scientific opinion agrees with him.
Such a rapid and sudden loss of species is not unprecedented but should nonetheless be a cause of serious alarm to us. The clues available from fossilised plants and animals point to several large-scale extinctions that have taken place in the past. The vast expanse of geological time in which there has been life on earth is punctuated with the dramatic disappearance of entire groups of animals and plants. The last time this happened was about 65 or 66 million years ago. What precipitated this event is unknown, although one idea has gained more support than others.
The most popular theory is that a comet or meteorite collided with the earth. One set of calculations suggest a 10-kilometre-wide object c
ame down in the present-day Gulf of Mexico. The impact created a cataclysmic explosion that hurled billions of tonnes of molten rock into the atmosphere; great tsunamis rammed the shores of the world’s oceans and blasted over the continents; forest fires raged everywhere. The debris and smoke blotted out the sun’s light for years. Poisonous rain fell from the clouds, temperatures plummeted and plant growth ceased. Food chains collapsed and many animals starved or died of cold in the ‘nuclear winter’ that followed. So catastrophic was this event that it wiped out many of the species of animals and plants alive at the time. The impact of the comet also brought an end to the age of the dinosaurs.
The geological record of the last half-billion years (more or less the period over which animals and plants have left abundant fossil remains in the rocks) is punctuated with several so-called mass extinctions like this one. The earliest occurred about 440 million years ago, the next at about 365 million, the one after at 245 and the next at about 210 million years before present. The last one was by no means the worst. The crash in the Permian period 245 million years ago involved the disappearance of between 77 and 96 per cent of all marine animal species. The cataclysm that brought about this level of species loss defies comprehension.
The richness of the natural diversity that surrounds us is mind-numbing, so vast is its variation and uniqueness. The disappearing birds, however, provide us with more manageable insights into the wider trends now unfolding. The feathered animals we take so much for granted today are the direct descendants of the dinosaurs; and like those long-lost reptiles many are now poised to follow their forebears to remain only as faint impressions in the rocks. Most powerful of all perhaps is the signal from the parrots. These birds have survived and thrived for tens of millions of years and become our closest emotional and social partners among the world’s birds. Their rapid disappearance is making a most dramatic point.