¿ìè¶ÌÊÓƵ

Perhaps Lord Curzon’s Man on the Clapham Omnibus doesn’t exist any more. But if you could find such a representative of average opinion, and if you said the word ‘Kuwait’, the reply might well be ‘Saddam Hussein’. If you said ‘Brazil’, it is not unlikely that, together with football and samba would come mention of the destruction of the tropical forest of Amazonia.

The reasons for concern are well-known, and they are certainly not for nothing. Yet there is a lot more to the 8 412 474 square kilometres of Brazil than jungle. That ‘more’ includes some 3 000 000 square kilometres-an area larger than the Mediterranean basin-of non-forest formations. The most striking of these habitats, the cerrado, the caatinga, and above all the campo rupestre, fall within the umbrella definition of ‘savanna’. There are no adequate translations of these Portugese words, but roughly speaking, the cerrado of central Brazil is grassland with shrubs and small trees, while the caatinga is dense thorny scrub with scattered largish trees, characteristic of the arid northeast of Brazil. The campo rupestre (which literally means ‘rocky fields’) is situated in the Espinhaco range of mountains in central and northeastern Brazil.

It is dangerously easy to believe that savanna, not luxuriantly green, not dense with noble trees, is, well, just about all the same. Research especially into the formation known as campo rupestre, reveals just how far from the truth such a notion may be. There is a quiet but growing conviction that the ‘other Brazil’, the Brazil with no rainforest, must be given greater attention before it is too late.

The Serra do Espinhao, a range of mountains whose name might broadly be translated as the Great Backbone Range, finds its southernmost limit in the central State of Minas Gerais. It dies away in the State of Bahia, 1100 kilometres to the north, in a number of scattered and isolated massifs. On the map, the Serra do Espinhao looks insubstantial, an amoebic archipelago, all islands and peninsulas. Nowhere is it very broad-it ranges from 50 to 100 kilometres wide. The highest peaks are just over 2000 metres above sea level. These mountains form the watershed between the Atlantic Ocean and the basin of the Sao Francisco river. Their landscape is very far removed from most of tropical Brazil; even so, they lie entirely within the tropics.

Traveller Sir Richard Burton, on his way to the diamond fields in 1867, failed to appreciate the biological potential of this region. He observed ‘. . . a fracas of nature, a land of crisp Serras stripped to the bones, prickly and bristly with peaky hills and fragments of pure rock separated by deep gashes and gorges. . . Here and there, between the stern peaks, lie patches of snow-white sand on a narrow bit of green plain, confused and orderless, a fibre in the core of rock-mountain.’

What Burton disapprovingly described is now familiar to biologists as the campo rupestre, and it is one of Brazil’s most fascinating ecosystems. At between 800 and 1800 metres above sea level, mountain grassland mingles with other herbaceous plants and small shrubs. Trees are few. Everywhere there are eroded quartzite outcrops; at higher altitudes these merge into ridges and summits of pure shattered rock. This is the dominant landscape of the Serra do Espinhao mountain range, and of a few other areas in the country, most of them in the State of Goias.

The Serra do Espinhao is utterly unlike the desert of Burton’s vision. It is rich, not only in diversity of life, but also in diversity of the environment that supports life. Habitat diversity is an important element in the process of speciation. Varied habitats, separated from each other by some form of barrier, form centres from which genetic potential can direct the evolution of new species. Sound conservation policy will not only protect the diversity of species, but also safeguard the diversity of environment which will stimulate further diversification of species.

The landscapes of the campo rupestre draw their character from their variety. Soils are poor, but the resulting substrates are numerous. There are patches of pure sand and patches of pebbles mixed with gravel. These are about as inviting as a garden path, yet each supports its forms of life. There is sand with humus, creating an acid formation with, at times, a pH as low as 3.5 (similar to vinegar!). There are areas of iron ore and related soils. Where drainage is impeded, acid bog may form.

As important as the soils are the rocks. The outcrops vary in size, from as small as a football to as large as an aircraft carrier. They create decisive barriers between distinct areas of terrain, and thus between distinct plant or animal populations. They provide shade, or shelter from prevailing winds, or they may increase heat by reflection. They are instrumental in the formation of microclimates and microhabitats.

The rocks themselves provide habitats. Numerous plant species are adapted to colonisation of their bare surfaces-mosses, lichens, orchids and bromeliads. Dead leaves and other organic matter in cracks offer growing conditions for plants of other types. The same cracks hold precious moisture, and afford shade and shelter for insects, reptiles and small mammals.

The landscape of the Serra do Espinhao may be seen as a long succession of distinct topographical areas, including mountains, rock outcrops, deep river valleys, gallery forests in strips along the more fertile watercourses, and at lower levels occasional patches of other formations such as cerrado and forest. Soils differ in structure, nutrient content and capacity for holding water; hillsides vary in their degree of slope and stability. All these factors create a range of microhabitats with different exposure to sun, wind and moisture. Seen from close to, this is no longer just a range of mountains; it is an assemblage of macro-and microhabitats, each separate, each related in a magnificent mosaic.

This is a landscape under stress, though. It has little of the stable benevolence of moist tropical forest. The primary stress factors are a huge seasonal range in temperature and shortage of water. Summer temperatures rarely exceed 30 °C, but that can mean a soil or rock-face temperature of between 50 °C and 60 °C during the seven months of the rainy ‘summer’ season. Yet in winter, temperatures slightly below zero are not unknown. Rainfall, at about 1500 millimetres per year, is hardly low, but drain-off is mostly rapid and irregular. Rain may be plentiful; streams and rivers abound. But available water in the soil is in short supply.

The initial impression-Burton’s impression-of uniformity in alliance with poverty, is caused in part by the occurrence of the same plant families over much of the Serra do Espinhao, though the species which represent those families are often very different in different regions. But there is another reason for apparent uniformity. The need for plants to adapt to harsh but broadly consistent stress factors has resulted in convergent evolution: the development, sometimes in widely different families, of similar strategies for adaptation and survival in the face of similar pressures.

Plants with a will to survive

These strategies are various and often ingenious. Orchids may have specialised root and pseudobulb systems which allow the plants to draw water from dew and mist. Some bromeliads collect atmospheric moisture by means of special hairs. Tightly furled rosettes of leaves, or leaf sheaths which remain on the stem after the leaves have fallen, act as reservoirs and as habitat for other life forms. Anatomical modification of roots and leaves gives greater water storage capacity and reduces loss through transpiration. Waxy leaf surfaces reflect heat and thick layers of hairs protect against radiation. Thickened bark, hard overlapping leaf sheaths and appropriate chemical secretions protect against fire. Many annual species cope by growing when stress is least and living the harsh summer season out as seed. The campo rupestre is a spectacular phenomenon, but life here is rough, and the inhabitants develop unique strategies for survival.

It is too early (but, we must hope, not too late) to assess with any precision the extent of the campo rupestre flora, and zoological research is still at a very early stage. The figures available so far suggest that species diversity is extremely high; this is to be expected in view of the diversity of potential habitat and the conditions for speciation. Two examples may serve for a rough comparison with figures from other regions of the world.

The area of Mucuge, in the State of Bahia, surveyed by personnel from the Royal Botanic Gardens, Kew and the Centro de Pesquisas do Cacau in Itabuna, show some 670 plant species in about 900 square kilometres. The Serra do Cipo, a small sub-region of the Serra do Espinhao, at much the same latitude as New Caledonia, has been extensively investigated by teams from the University of Sao Paulo and the Sao Paulo Institute of Botany. Results to date show an extraordinary 1590 species in an area of only 200 square kilometres. Similar or higher counts, involving different species, are expected from elsewhere in the mountain range. (As a comparison, the whole of the British Isles, with an area of 151 000 square kilometres, has only about 1500 species of plants.)

A unique source of life

These preliminary figures argue eloquently for the need to protect the area, but it is not just the numbers of species which count. The Serra do Espinhao has clearly been, in the past, a prolific centre of speciation. It is to be supposed that it still is. This is reflected in the fact that about 30 per cent of all species known from the region are endemic-that is, they are found there and nowhere else in the world.

Nanuza Menezes, of the University of Sao Paulo, a specialist in the family Velloziaceae, points out that of some 200 Brazilian species in that rather weird and wonderful family, all but six are endemic to the campo rupestre. But there is endemism and endemism. Some endemic species are widespread throughout the range. Others occur in scattered and separate populations; each such population is the potential genetic basis for a new species. Some species exist only in one small section of the entire range.

Ana Maria Giulietti, also of the University of Sao Paulo, who with Menezes has done so much to defend the campo rupestre, cites the case of one single massif, which is the habitat for three striking species of the ornamental genus Syngonanthus (Eriocaulaceae). None of the three is known to exist anywhere else. Yet each is endemic, not to the massif but to the slopes of just one of its faces. None of the three overlaps into the territory occupied by either of the others. Of 45 or so species of the family Xyridaceae known to Maria das Graas Wanderley (of the Institute of Botany, Sao Paulo), from the 200 square kilometres of the Serra do Cipo, 15 are endemic, while between 100 and 150 are endemic to the campo rupestre in general. The Serra do Cipo has 17 known endemic species of reptile.

While the world watches Amazonia with anxious eyes, the Brazilian savannas, including the Serra do Espinhao, are in danger. The chapter on the natural environment in Brazil’s 1988 constitution defines the Amazon forest, the Atlantic forest, the Serra do Mar, the Pantanal region of Matto Grosso, and the sea coast as national heritage areas. In theory, though perhaps no more, this guarantees them protection.

Under pressure from politicians representing landowner interests and agribusiness, the constituent assembly refused that protection to the savanna regions-the caatinga in the north-east, the cerrado in the centre and west, and, by extension, the campo rupestre. These areas, considered as ‘trash vegetation’, are wide open to exploitation and development, as a quid pro quo for the forests.

Specific threats to the biological wealth of the campo rupestre are various and serious. The unsuitability of the region for mechanised agriculture is in its favour. Even so, soya bean and sugar cane are making their unwelcome appearance. Campo rupestre has no timber trees to speak of, but attempts have been made and will be made again to plant exotics, including pines and the ubiquitous and obnoxious eucalyptus. The steel industry makes voracious demands on the area’s capacity to produce charcoal from almost anything with a woody stem; likewise in the cerrado. The resinous stems of the larger species of Vellozia were once used as fuel for locomotives on the Curvelo-Diamantina railway line, and these days are to be found in stacks by the roadside, on sale as fuel for wood stoves and to make primitive torches. A big Vellozia may take 100 years to reach an adult (and combustible) state.

The abundant grass cover gives the campo rupestre useful potential as natural pasture. Farmers frequently burn back old vegetation at the beginning of the dry season to stimulate new tender growth for hungry cattle. Many plant species have evolved protective mechanisms and can survive periodic fires. Many cannot, and nor can insects, reptiles, mammals and a lot of birds.

Dried flower heads of some 33 plant species, several of them rare endemics, are much in demand as ornamental ‘everlasting’ flowers, particularly for export to the US, Japan and Europe. Statistics compiled by Nelson Giulietti (of the Secretariat for Agriculture of the State of Sao Paulo) and others show that in the year 1984, in the region of Diamantina alone, no fewer than 257 tonnes (dry weight) of these almost weightless ‘flowers’ were harvested. Several species, including three in the genus Syngonanthus, prized for their beauty, are on the endangered list. Yet this industry is a major item in the economy of at least eight depressed regions of the campo rupestre. Entire families spend months at a time in the field, collecting these flowers for what they can get for them. A policy of sustainable development offers hope for a balance between the survival of plants and the survival of people who live in the area.

More showy plants, particularly orchids, bromeliads and cacti, fall victim to predatory collectors. Young plants of the rare and very local cushion cactus Parodia gummifera are still regularly removed from their only known site, destined for the unscrupulous collector.

Opencast iron mining occurs on a huge scale. Surface mining for gold occurs on the campo rupestre in Bahia. There is manganese mining on the Serra do Cipo, one of the few areas of the campo rupestre to enjoy the promise of official protection as a national park. Diamond washing may interfere with watercourses, causing silting and erosion. And then there is just ‘mining’-the turning over of great areas of land by the poor of a depressed region in the hope that something might turn up. Mining pits from the early 19th century can still be detected. Poorly planned road construction causes erosion on a catastrophic scale. The scars on the land take a long time to heal. The lost species can never be brought back.

‘Green’, full of the symbology of life itself, is an emotive and politically loaded word. It is easy to associate green with biological plenty and diversity; conversely, there is a common tendency to suppose that less-than-lush landscapes are somehow short on biodiversity. Indeed, such ‘trash’ landscapes may well invite the traditional attitude (imported from Europe) that it is an act of virtue to convert them for the benefit and profit of humanity.

The riches of the campo rupestre are proof that things may sometimes be otherwise. Jose Pirani, of the University of Sao Paulo, points out, and most botanists agree, that the cerrado (fine country for tractor and artificial fertiliser) is far from the uniform, and thus dispensable, savanna ecosystem which it is often stated to be. At species level, the flora of the cerrado may be widely different in different parts of Brazil. This demands investigation. Yet huge areas are turned over every year to soya bean and sugar cane, with very little control over management procedures. Insecticides and herbicides are causing widespread damage. Water sources are polluted, traditional ways of life undermined.

It is probably inevitable that, given Brazil’s economic problems and population pressures, substantial areas of this ‘other Brazil’ will be marked for agricultural development. This policy may well go unquestioned, as the price of concessions over Amazonia, and will have the deceptively beneficial support of international financial agencies. Brazilian universities and research establishments, with the aid of the World Wide Fund for Nature and a variety of foreign organisations and individual scientists, are putting up a fight against heavy odds. But it is well to remember that biodiversity, an unreplaceable part of our heritage and a potential force for the improvement of our lives, extends far beyond the edge of the forest.

Alasdair Burman is a grass taxonomist at the Botanical Institute in Sao Paulo, Brazil, and a member of the IUCN Species Survival Commission (Brazil Plant Specialist Group).

* * *

Conquering mountains because plants are there

For more than a decade, researchers at the Royal Botanic Gardens at Kew, with their colleagues in Brazil, have been mapping the plants of the remote mountainous habitats in northeastern Brazil known as campo rupestre. Each expedition discovers new species found nowhere else on Earth.

The botanists from Kew are working closely with researchers at the Centro de Pesquisas do Cacau (CEPEC) at Itabuna in Bahia, Brazil, and at the University of Sao Paulo. The plan is to survey intensively the plants living in selected mountainous sites in the Serra do Espinhao of Minas Gerais and Bahia, and to publish inventories.

This approach is the most cost-effective way of discovering the diversity of the plant life, the way various species are distributed and the extent to which plants living in the region are endemic, or unique to that region. These inventories also provide valuable records for researchers in other disciplines such as zoologists and ecologists, as well as a focus for further research and teaching.

So far, the inventories of two such areas have been published-the Serra do Cipo in the University of Sao Paulo and Mucuge by Kew. Both areas are now national parks, partly as a result of this research initiative. The university’s researchers are well on the way to completing the Flora of Grao Mogol.

Kew’s research on the campo rupestre now focuses on the area around the Pico das Almas, a mountain nearly 2000 metres high near the small town of Rio de Contas in Bahia. Until very recently, little was known about the flora of this remote region. The first botanist to climb the mountain was P. von Luetzelburg in 1912 but he collected very few plants. As far as we know, no other botanist visited until 1974 when a team from Kew and the CEPEC, led by Raymond Harley of Kew, paid a brief visit. Researchers from these and one or two other institutes made further brief visits in subsequent years but the mountain remained virtually unexplored, botanically speaking.

But these early visits did provide evidence of the great floristic richness of the Pico, and many of the species described were new to science. So towards the end of 1988, Kew and its Brazilian collaborators mounted a major expedition to the mountain. Despite near disaster, when the whole camp and all the equipment was washed away by a freak flood, the expedition was a great success. Many specialists in Britain and abroad have closely studied the plants collected, and their labours are near completion. Already, more than 30 new species of plants have been recorded from this last field trip, adding to those previously described and providing even more evidence of the outstanding scientific importance of the region. Descriptions, keys and illustrations of the flora, now totalling about 1200 species, will be published later this year, as the Florula of the Pico das Almas.

Plans are now afoot to explore an area of campo rupestre further north in the same mountain chain. This project will fall under the umbrella of the Projeto Nordeste, a major Kew/Brazilian initiative which aims to carry out the scientific work essential to the rehabilitation of the degraded ecosystems of northeastern Brazil. These include the caatinga forest, the Atlantic forest, seasonal semi-deciduous and evergreen forests, as well as the vegetation of the mountainous campo rupestre.

Brian Stannard and Raymond Harley

Brian Stannard and Raymond Harley are taxonomic botanists at the Royal Botanic Gardens, Kew.