The Improvement of Tropical and Subtropical Rangelands (BOSTID): Part I: The nature of tropical and subtropical rangelands: Range classification

The Improvement of Tropical and Subtropical Rangelands (BOSTID)

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Acknowledgements

Panel on the improvement of tropical and subtropical rangelands

Contributors

National research council staff

Preface

Overview: Dimensions of a worldwide environmental crisis

The geographical scope

References

Part I

Introduction

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References

The nature of tropical and subtropical rangelands

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Range classification

Social system-ecosystem interactions

References

The social context for rangeland improvement

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Production systems in tropical and subtropical regions

Context of environmental degradation

References

The economic context

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Range systems

The basis of range economics

Project analysis

Determining costs and benefits

Resource evaluation

Market price determination

References

Regional resource assessment

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Information needs

Information acquisition

References

Site evaluation

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An ecosystem perspective

A systems approach to site evaluation

Evaluation of abiotic and biotic components

Integrated evaluations

References

Grazing management

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Grazing management concepts

Time of grazing

Distribution of grazing

Type of animal grazing

Number of animals grazing

Grazing management planning

Grazing management systems

Livestock management

The herima system in Mali

References

Rehabilitation techniques

Establishing plants on the range

Natural revegetation

Direct seeding

Improvement of tropical and subtropical rangelands

Selected practices

References

Criteria for plant selection

Project planning

Socioeconomic and management considerations in feasibility studies

Adaptation to ecoclimatic conditions

Adaptation to soils

Adaptation to physiography, geomorphology, topography, slope, and aspect

Ability of introduced species to compete with native vegetation

Use regimes

Availability of seeds and plant materials

Maintenance of biological diversity

Plant improvement

References

Part II

Introduction to the case studies

Pastoral regimes of Mauritania

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Physical geography

Migration cycle

The Beni Mguild of Morocco

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Physical geography

Migratory cycle

The Kel Tamasheq

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Introduction

Camp organization

References

Dromedary pastoralism in Africa and Arabia

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Introduction

Reproduction and risk

Management and labor

Subsistence production

Marketing

Predatory pastoralism

The future of camel pastoralism

References

The mountain nomads of Iran: Basseri and Bakhtiari

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The physical environment

The basseri

The bakhtiari

The Marri Baluch of Pakistan

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Physical environment

Seasons and migrations

A mixed economic system

Conclusiones

Changing patterns of resource use in the Bedthi-Aghanashini valleys of Karnataka state, India

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Introduction

The setting

Human communities

Traditional patterns of resource management

Colonial period

After independence

Recent trends

References

Kenya: Seeking remedies for desert encroachment

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Introduction

Background

Traditional pastoralism

Baseline studies

Vegetation and livestock

Directions for the future

The hema system in the Arabian peninsula

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Rights of ownership or use

The hema system in Saudi Arabia

The mahmia or marah, and the koze system in Syria

Neglect of the hema and its consequences

Hema in the range improvement and conservation programs in the near east

References

Wildlife land use at the Athi River, Kenya

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Background

Some early findings

Conclusion

Camel husbandry in Kenya: Increasing the productivity of ranchland

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Introduction

Location

Vegetation

Livestock

Introduction of camels

Management and adaptability

Reproduction and lactation

Veterinary notes

Economics

Reference

The potential of faidherbia albida for desertification control and increased productivity in Chad

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Background

Characteristics of faidherbia albida

Project description

Project analysis and evaluation

Conclusions

References

Improving Nigeria's animal feed resources: Pastoralists and scientists cooperate in fodder bank research

Board on science technology for international development

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Members

Range classification

Range management issues are usefully considered within the context of ecoclimatic zones. In this report, these zones are defined largely on the basis of land potential and moisture availability (Pratt and Gwynne, 1977). Within the tropics, five such zones can be distinguished:

1. Humid to dry subhumid (moisture index not less than -10).(2) This zone is characterized by forest and derived grasslands and bushlands, with or without natural glades. The grestest potential is for forestry (perhaps combined with wildlife and tourism), or intensive agriculture. The natural grasslands of this zone require intensive management for optimum production. Approximately 0.8 hectare is required per livestock unit, depending upon the related grassland association. (3) In this zone, approximately 2.5 livestock units are required to support one subsistence pastoralist; hence, 2 hectares are required to support each individual. The maximum population density per km² is about 50 pastoralists (see table 1-1).
2. Dry subhumid to semiarid (moisture index -10 to -80). The vegetation of this zone includes moist woodland, bushland, and savanna. Forestry potential is low. However, the agricultural potential is relatively high, soils and topography permitting, with emphasis on lea farming. Large areas are generally under range use and, with intensive management, can carry 1 livestock unit per 1.6 hectares. Approximately 3 livestock units are required to support 1 subsistence pastoralist. Thus, 4.8 hectares are required to support 1 individual. The maximum density of pastoralists would be approximately 21 per km². Regular burning is an important management tool in this zone.
3. Semiarid (moisture index -30 to -42). These are areas with marginal agricultural potential, which in some regions is limited to rapidly maturing grains. The natural vegetation is characteristically dry woodland and savanna. This is potentially productive rangeland. Approximately 3.5 hectares are required per livestock unit, except where dry seasons exceed 6 months. The corresponding human carrying capability is 7 individuals per km². Animal husbandry is limited principally by the encroachment of woody vegetation and, in some locations, by leached soils. In many areas, particularly in Africa, the more open country with a high density of wildlife is a valuable tourist attraction.

TABLE 1-1 Relationship between Ecological Zone, Livestock Carrying Capacity, and Maximum Population Density under Subsistence Pastoralism

	Ecoclimatic Zones
	1	2	3	4	6
Hectares required per livestock unit	0.8	1.6	4.0	12.0	42.0
Livestock units required to support one head of population	2.6	3.0	3.6	4.0	4.6
Hectares required per head of population	2.0	4.0	14.8	48.0	189.0
Maximum population density per km²^a	60.0	21.0	7.0	2.0	0.6

^a These figures presume that all land is accessible and productive; if actual population density under subsistence pastoralism even approaches these estimates, overpopulation is indicated. Higher population can only be sustained if the pastoralists derive a substantial part of their subsistence from vegetable foods--collected, grown, or procured in exchange for livestock.

SOURCE: Modified after Pratt, 1968.

4. Arid (moisture index -42 to -51). This zone is suitable for agriculture only where fertile soils coincide with a favorable distribution of precipitation, or where rainwater is concentrated in depressions. Many arid rangelands are dominated by species of Acacia or Prosopis. Perennial grasses, such as Cenchrus ciliaris, can be prominent, but succumb quickly to inadequate management. As many as 12 hectares may be required per livestock unit. Wildlife is important, particularly where dry thorn-bushland predominates. Burning requires caution but can be highly effective in range manipulation. Approximately 4 livestock units are required to support 1 subsistence pastoralist, and the maximum population density per km² is 2 individuals.
5. Very arid (moisture index -51 to -57). This zone supports rangeland with relatively low potential. The characteristic vegetation is shrub or grass steppe, with trees largely confined to water courses and seasonally inundated depressions. Perennial grasses, once dominant in many areas, are now localized within a predominantly annual grassland. Growth is confined largely to the seasonal flushes characteristic of summer therophyte vegetative communities, and grazing systems are generally based on pastoralism. Populations of both wild and domesticated animals are restricted by temperature, forage, and available moisture (Schmidt-Nielsen, 1964).

Systems of range classification should be regionally adjusted to include descriptions of the existing vegetation in physiognomic terms, with subdivisions by species composition.