This chapter intentionally overlaps with Chapter 4 in its geographical scope, as there is no clear boundary between South-West and South Asia. Western Asiatic landforms—mountain ranges, alluvial valleys, semi-arid steppe, and desert—extend eastwards from the Iranian plateau beyond the Caspian Sea into Turkmenistan in Central Asia, and there are similar environments in South Asia from Baluchistan (western Pakistan) and the Indus valley into north-west India as far east as the Aravalli hills (Fig. 5.1). Rainfall increases steadily moving eastwards across the vast and immensely fertile alluvial plains of northern India. The north-east (Bengal, Assam, Bhutan) is tropical, with tropical conditions also extending down the eastern coast of the peninsula and up the west coast as far as Bombay. Today the great majority of the rural population of the region lives by agriculture, though many farmers also hunt game if they have the opportunity. The ‘Eurasian’ farming system predominates in the western part of the region: the cultivation of crops sown in the winter and harvested in the spring (rabi), such as barley, wheat, oats, lentils, chickpeas, jujube, mustard, and grass peas, integrated with animal husbandry based especially on sheep, goats, and cattle. A second system (kharif ) takes advantage of the summer monsoon rains: crops are sown in the late spring at the start of the monsoon and harvested in the autumn. Rice (Oryza sativa) is the main summer or kharif crop (though millets and pulses are also key staples), grown wherever its considerable moisture needs can be met, commonly by rainfall in upland swidden systems and on the lowlands by flooding bunded or dyked fields in paddy systems. The systems are referred to as ‘dry’ and ‘wet’ rice farming respectively. Rice is the primary staple in the eastern or tropical zone receiving the greatest amount of summer monsoon rain. This extends from the Ganges (Ganga) valley eastwards through Assam into Myanmar (Burma) and East Asia. There are something like 100,000 varieties of domesticated Asian rice, but the main one grown in the region is Oryza indica. A wide range of millets is also grown as summer crops in rain-fed systems throughout the semi-arid tropical regions of South Asia, including sorghum or ‘great millet’, finger millet, pearl or bullrush millet, proso or common millet, foxtail millet, bristley foxtail, browntopmillet, kodo millet, littlemillet, and sawamillet.
Seed Dispersal by Ants in the Semi-arid Caatinga of North-east Brazil
