The Fragile Tropics of Latin America: Sustainable Management of Changing Environments (1995): Part 4 : The semi-arid north-east: White sand soils in north-east Brazil: 2 Site characteristics

The Fragile Tropics of Latin America: Sustainable Management of Changing Environments (1995)

Acknowledgements

Introduction

Part 1 : The ecological outlook

Ecological prospective for tropical Latin America

(introductory text)

1 Introduction

2 The current condition of the tropical Latin American ecosystems

3 Modelling ecological changes

4 The reference scenario

5 The sustainable scenario

6 Conclusions

Acknowledgements

Notes

References

Rich and poor ecosystems of Amazonia: an approach to management

(introductory text)

1 Introduction

2 Characterization of the oligotrophic environment

3 Characterization of eutrophic forests

4 Management of oligotrophic areas

5 Management of eutrophic areas

6 Conclusions

Acknowledgements

References

Archaeological perspectives on the potential of Amazonia for intensive exploitation

(introductory text)

1 Introduction

2 Evolutionary principles

3 Past and present settlement behaviour

4 Relations between várzea, and terra firme groups

5 The impact of climatic fluctuation

6 Overcoming environmental constraints

7 Conclusion

Acknowledgements

References

Distribution and interannual variability of rainfall in Brazil

(introductory text)

1 Introduction

2 Data source and distribution of rainfall in South America

3 Interannual variability of rainfall in brazil

4 Relationship to southern oscillation Index

5 Seasonal variability of rainfall in Brazil

6 Comparison of the rainfall in northern Brazil to other tropical regions

7 Conclusion

Acknowledgement

References

Part 2 : The Brazilian Amazon

Waters and wetlands of Brazilian Amazonia: an uncertain future

(introductory text)

Sweet sea

The Amazon river system

Human use of Amazonian aquatic and wetland ecosystems

The future, a cascade of uncertainties

A broader picture: environmental perspectives in Brazil

Conclusions

Acknowledgements

Notes

References

A fragile capitalism in a fragile environment: entrepreneurs and state bureaucracies in the free zone of Manaus

(introductory text)

1 Introduction

2 Methodological remarks

3 A theoretical excursus

4 Entrepreneurs and bureaucrats

5 Findings

Notes

References

Part 3 : The Peruvian Amazon

Aquatic and land fauna management among the floodplain ribereños of the Peruvian Amazon

(introductory text)

1 Introduction

2 The ribereños of San Jorge

3 The Amazon floodplain in north-east Peru

4 Ribereño hunting

5 Fishing

6 Distribution and consumption

7 Changes in fisheries

8 Conclusion

Acknowledgements

References

Subsistence- and market-oriented agroforestry in the Peruvian Amazon

(introductory text)

1 Introduction

2 Traditional agroforestry in north-eastern Peru

3 Swidden-fallow agroforestry among the Bora indians

4 Market-oriented agroforestry in Tamshiyacu

5 Conclusions and recommendations

References

Local management of forest resources in a rural community in north-east Peru

(introductory text)

1 Introduction

2 Study area and objectives

3 Population dynamics

4 Distribution and use of terra firme lands in the community

5 Traditional use of forest resources

6 Prospects for sustainable management

Acknowledgements

References

Part 4 : The semi-arid north-east

White sand soils in north-east Brazil

(introductory text)

1 Introduction

2 Site characteristics

3 Distribution of the white sand soils in the Paraíba-Pernambuco area

4 White sand on the Conde upland, Paraíba

5 Origin of upland white sand

6 The effect of deforestation

References

Changing aspects of drought-deciduous vegetation in the semiarid region of north-east Brazil

(introductory text)

1 Introduction

2 Study sites and methods

3 Results

4 Discussion and conclusion

References

Characteristics and utilization of tree species in the semi-arid woodland of north-east Brazil

(introductory text)

1 Introduction

2 Bioclimatic divisions of north-east Brazil and the floristic composition of the caatinga stand

3 Response and stress tolerance of caatinga trees to various water conditions

4 Utilization of the caatinga trees

5 Deforestation associated with increased firewood consumption and charcoal production

6 Conclusions and a proposal

Acknowledgements

Appendix

References

Drought, irrigation, and changes in the sertão of north-east Brazil

(introductory text)

1 Introduction

2 Reservoir irrigation in Paraíba

3 Middle São Francisco valley

4 Consequences of irrigation agriculture

Acknowledgement

References

2 Site characteristics

2 Site characteristics

Broadly speaking, the North-East consists of three distinctive geoecological regions: the zona da mata, the agreste, and the sertão (Andrade, 1980). They are arranged zonally in this order from the Atlantic coast to the inland (fig. 11.2).

The zona da mata do Nordeste is part of the extensive forest zone that stretches along the Atlantic coast from the north-east to the south-east of Brazil. It enjoys a sub-humid climate with marked seasonality. That is, the annual rainfall amounts 1,000 to 2,000 mm, but there is a weak dry season for two or three months when the monthly rainfall is less than 50 mm. Its original plant cover was generally a tropical evergreen seasonal forest, although because of long continued developments in the region, little original vegetation remains.

Figure 11.2 Schematic cross-profile of landform and geology, and distribution of white sand soils in the state of Paraíba, along the latitude of about 7°S. (After Machida et al., 1976.) (1) crystalline basement (Precambrian gneiss, granite, schist, etc.);(2) Cretaceous sedimentary rocks (sandstone, limestone, etc.); (3) Pliocene and Pleistocene sediment (Barreiras Group).

The geomorphology of the zone da mate is characterized, by low uplands called tabuleiros, although in some parts, such as southern Pernambuco, there are low, rounded hills ("half oranges" or colinas) of deeply weathered crystalline rocks. The tabuleiros are low uplands 30 to 200 metres above sealevel. They have been dissected to a greater or lesser degree by numerous valleys; consequently, some appear as extensive flat uplands; others are only residual fragments (fig. 11.3). They are composed of sandy, permeable, and unconsolidated sediments of Pliocene to Pleistocene age (Barreiras Group). The tabuleiros are largely grouped into three geomorphic surfaces: the higher and older erosional surface; the lower and later depositional surface; and the lowest fluvial terrace surfaces (Matsumoto, 1983). Geologically and geomorphologically, the tabuleiros in the North-East are correlated with the terra firme uplands that predominate in the Amazonian lowland.

The sertão is a semi-arid inland area, and a part of Brazilian plateau (Borborema highland), on which low-relief erosional plains (pediplains) have developed on the crystalline rocks. The annual rainfall in the sertão ranges 500 to 800 mm, and there is a six- to ten-months-long, almost rainless, severe dry season. A type of drought-resistant xerophytic vegetation called caatinga dominates.

The agreste is the transitional zone between the zone da mate and the sertão.

Locally, within the generally semi-arid sertão or the agreste, however, there are some small isolated sub-humid areas covered by forest. Such areas, called brejos, are formed generally on and around isolated heights standing above the plateau surface.