Sarfraz Ahmad and Muhammad Islam

Arid Zone Research Centre, Quetta,

Pakistan

1. Introduction

Pakistan has total land area of 88 million hectare (ha) and about 65% of this is rangelands. Five different types of range ecological zones (Sub-alpine and temperate, Sub-tropical humid, Sub-tropical sub-humid, Tropical arid and semi-arid deserts plains, and Mediterranean) have been described in Pakistan (Khan & Mohammad, 1987). These rangelands are the major feed source of about 97 million heads of livestock. Precipitation varies from 125 mm to over 1500 mm per annum. About 60 to 70% of monsoon rains received during the months of July to September while the winter rains occur from December to February (Khan, 1987).

Balochistan has a total area of 34 million ha of which only 4% (1.47 m ha) is under cultivation while 60% of the cultivated area is rainfed (Khan, 1987). Approximately, 93 % of this province (Fig. 1) is characterized as rangelands (FAO, 1983) Arid and semi-arid areas are falling within the rainfall zones of 50-200 mm and 250-400 mm, respectively (Kidd et al.,

1988) . Rainfall patterns are unpredictable with great variations. Like other arid and semiarid rangelands of the world, Balochistan ranges also provide a diversity of uses, including forage for livestock, wildlife habitat, medicinal plants, water storage and distribution, energy, minerals, fuel wood, recreational activity, wilderness and natural beauty.

Livestock rearing is the main activity of the inhabitants of Balochistan. Sheep and goats are the main livestock of the province. About 87% of the people in Balochistan directly or indirectly drive their livelihood from livestock rearing (Heymell, 1989). About 20 million sheep and goats population have been reported in Balochistan (GOB, 1996 ). Rangelands are the major feed source of these animals and approximately 90% of total feed requirements of sheep and goats were being met from rangelands (FAO, 1983). Overgrazing, drought, erosion, and human induced stresses caused severe degradation of rangelands in Balochistan (Islam et al., 2008; Hussain & Durrani, 2007). The degradation of rangelands includes changes in composition of desirable plant species, a decrease in rangeland diversity and productivity, reduction of perennial plant cover, and soil erosion (Milton et al., 1994).

In Balochistan, the mixed grass-shrub steppe is more common than single plant communities. The range vegetation types in Balochistan changes from south to north along the rainfall distribution. In South, shrub species Haloxylon species and Artemisia species while in north perennial grass species Cymbopogon jwarancusa and Chrysopogon aucheri are dominant. The fragile ranges of Balochistan are degrading very rapidly due to heavy

grazing pressure, aridity, and human disturbances. However, still many of these ranges have potential for improvement by using grazing management practices, natural recovery of vegetation and artificial re-vegetation at suitable sites coupled with better water harvesting and conservation practices.

Natural re-vegetation practices particularly grazing management may restore vigor and accelerate the spread of desirable species (Vallentine, 1980). Grazing management alone may not accelerate the succession towards desirable species in arid and semiarid rangelands due to limited precipitation where artificial re-vegetation would involve the establishment of adapted species either by seed or transplanting seedlings (Roundy & Call, 1988). Restoration and rehabilitation are the two main procedures for regeneration of a depleted rangeland. Restoration or biological recovery means to bring the ecosystem to their pristine situation and rehabilitation or artificial recovery is the artificial establishment of a new type of vegetation different from the pristine native vegetation (Le Houerou, 2000). Biological or artificial recovery may include increase in biomass, plant cover, organic matter, soil micro and macro-organisms, better water intake and turnover, lower evaporation and runoff. Biological recovery may be obtained by protecting the target area from human and livestock intrusion. The purpose of rehabilitation of rangelands may be diverse like forage production, timber production, landscaping, wind breaks, sand dune fixation, and erosion control (Le Houerou, 2000).

A major concern of arid and semiarid ranges is the progressive reduction of secondary productivity and diversity (West, 1993) and how to manage these changes (Walker, 1993). The management and improvement of arid and semi-arid ranges is always a challenging job. Different theoretical models of rangelands have been developed and few are also being tested in different rangeland ecosystems of the world. However, the arid rangeland ecosystem of Balochistan is very dynamic where major climatic and agricultural changes are occurring. Hence many range management projects were carried out with little success.

Therefore, there is a need to re-look into research, policy and management issues for better productivity of rangelands and livestock.