Previous background introductory pages have outlined the distribution, biodiversity, flora and the history of botanical exploration of the cerrado biome. The following notes deal with the present situation of the biome in terms of exploitation and conservation.

When one of us (J.A. Ratter) started work in the cerrado 43 years ago the area was largely occupied by small (often subsistence) farmers, backwoodsmen, and, at least it its remoter areas, by indians. The cerrado was not considered suitable for arable cultivation and was only used for low density cattle-grazing on the native vegetation. The residents grew crops of rice, mandioca and other vegetables for domestic use in clearings on the better soils of the gallery and other forests, as well as keeping a few pigs, other domestic animals and poultry. Their diet was usually much improved by the abundance of excellent food-fishes in the rivers and a plentiful supply of game. Charcoal burning also supplied a source of income for those who lived close to adequate roads.

However, this rustic idyll was to change with a rapidity that few people could have visualized at the time: super-mechanized, capital intensive agribusiness, in its early stages massively subsidised by Brazilian Government support, took over the landscape. Research had demonstrated that cerrado soils were of excellent texture for cultivation but were very acid and contained high levels of aluminium toxic to crops. This could be counteracted by massive application of lime – so massive that the expense far outweighed the initial cost of the land! Despite this, funds were supplied for clearing the land of its native cerrado vegetation, application of lime and preparation of the soil. Following this, grain crops of principally soya, maize, rice, millet, etc were cultivated and their harvest by 2010 reached nearly 150 million tonnes (Brazilian Ministry of Agriculture figures from The Economist 31.08.10 – admittedly some of this production from land outside the cerrado biome). However, far more of these ‘improved areas’ of the cerrado have been used for pastures than for arable and are sown with such vigorous exotic grasses as Brachiaria, Hyparrhenia rufa and Panicum maximum. They support huge herds of cattle, particularly of the humped white Nelore breed and much of the meat is exported. Another important use of improved cerrado land has been for the cultivation of sugarcane for the production of biofuel for vehicles. In the middle of the 1970s this was a very active business but with the later fall in oil prices became unprofitable and much of the production was abandoned. However, the rise in price of petroleum has brought back increased interest in the business and enormous plans for its expansion.

The modern system of cultivation of the cerrado is far from environmentally friendly. Employment of intensive mechanization with fleets of giant tractors and combine harvesters requires huge fields, meaning that small animals have to traverse great areas to reach other patches of natural vegetation. In the early days of the giant monocultures the practice of leaving great areas of uncovered soil after harvest led to great rain and wind erosion causing not only the loss of topsoil but the silting of watercourses. However, the practice of ‘nil cultivation’ whereby seed of the next crop is drilled through the remains the last one without ploughing has greatly improved this situation – as well as providing a huge saving of diesel fuel. John Landers, a British agronomist who has worked in Brazil since 1966, has been a passionate advocate of ‘nil cultivation’ over many years and his efforts have greatly promoted its adoption.

There has been a strong tendency amongst world conservation organisations to emphasize the conservation of the Amazon tall forest (original area in Brazil 3.5 million sq. km.) while neglecting the importance of the cerrado (original area 2 million sq. km.). However, the destruction (or ‘conversion to anthropic landscape’) of the cerrado biome, both in absolute and relative terms far exceeds that of the Amazon tall forest. It is also forgotten that cerrado is a very important vegetation within Amazonia (it covers 700,000 sq. km of Amazonia Legal (Brazilian Legal Amazonia)) and in addition dominates areas of the Amazon Basin not officially included in this legal category (principally more than 200,000 sq. km. in the north of the State of Goiás (Ratter et al., 2006)). Since so much of the southern drainage of the Amazon lies in the cerrado biome it is bound to be affected by vegetation clearance there (both of cerrado and the great band of cerrado/dry forest transitional vegetation). As emphasized in a very recent authoritative paper by Malhado et al. (2010) the Amazon forest biome should not be considered in isolation: its sustainability depends upon the conservation of the adjoining cerrado. The ultimate, and quite possible, scenario is that extreme destruction of the latter might lead to so much atmospheric drying that the heat/moisture conveyor of the trade-wind westwards along the course of the Amazon River is disrupted. Such disruption could bring about profound changes in world climate patterns and drastic cooling of the European climate, possibly even leading to a new Ice-Age.

How much of the cerrado has been destroyed?

Calculations based on remote-sensing imagery showed that 66% of the cerrado biome had already been deforested in 2004 (Machado et al., 2004) and, allowing an estimate by these authors of an annual loss of 1.1% this can now certainly be estimated as over 70%, representing an area of about 1.5 million sq. km. Clearly the need for conservation is urgent both for preservation of the biome’s rich biodiversity and for conservation of climate and other resources. In fact, Brazil’s conservation regulations are excellent and if they were strictly observed would ensure a very sensible level of conservation. They require preservation of 20% of the natural cerrado vegetation as well as total preservation of gallery (riverine) forests by watercourses and their headwaters. Sadly it is difficult to enforce these regulations over the huge areas involved and there are also many loopholes, so they are frequently flouted. Unfortunately there is also a great lack of designated reserves (federal, state, private and other) and in total they represent only a tiny percentage of the vast cerrado biome so that in terms of conservation much requires to be done.

References:

Anon (2010). The miracle of the cerrado. The Economist. 31.08.2010. http://www.economist.com/node/16886442

Machado, R. B., Ramos Neto. M. B., Pereira, P. G. P., Caldos, E. F., Gonçalvez, D. A., Santos, N. S., Tabor, K. & Steininger, M. (2004). Estimativas de perda da área do cerrado brasileiro. Unpublished Technical Report. Conservação Internacional, Brasília, DF, Brazil. http: http://www.conservation.org.br/arquivos/Relat Dermatam cerrado.pdf

Ratter, J. A., Ribeiro, J. F. & Bridgewater, S. (1997). The Brazilian cerrado vegetation and threats to its biodiversity. Annals of Botany 80: 223-230.

Ratter, J. A., Ribeiro, J. F. & Bridgewater, S. (2006). The Cerrado of Brazilian Amazonia – A Much-Endangered Vegetation. In Posey, D.A. & Balick M.J. eds. Human Impacts on Amazonia. Ch. 5, pp. 85-97. Columbia University Press, New York.

Ratter, J. A., Bridgewater, S. & Ribeiro, J. F. (2006). Biodiversity Patterns of the Woody Vegetation of the Brazilian Cerrado. pp. 31-66. In: Pennington, R. T., Lewis, G. P. & Ratter, J. A. (eds.). Neotropical Savannas and Seasonally Dry Forests: Plant Diversity, Biogeography, and Conservation. CRC Press, Taylor & Francis Group, Boca Raton, Florida, USA