Can management of ‘thirsty’ alien trees improve water security in semi-arid India?

Abstract

Arid and semi-arid regions of central India receive scarce and episodic precipitation during the short monsoon season, and also experience substantial evaporation. Traditional and innovative water harvesting and governance practices improve water stewardship, or abate some impacts of intensive mechanised water extraction. However, significant numbers of alien trees, in particular Eucalyptus species with high water demands, populate some regions practicing progressive water stewardship. The water demands of these trees can potentially undermine efforts to achieve water security. Through interviews with community leaders in Indian villages with differing eucalyptus tree densities, water loss through evapotranspiration compared with livelihood demands was approximated. Literature review of the water demands and ecosystem services provided respectively by alien eucalypts and native, culturally valued neem trees supports assessment of the likely benefits and acceptability of a replacement programme favouring native trees. Although data limitations mean that the findings of this study are necessarily uncertain, they nonetheless illustrate the likely scale of impact, substantiating the case for alien tree management as an important contribution to water security. Alien vegetation management practices as a contribution to water security are already firmly established in South Africa, and are likely to yield equivalent benefits if translated to dryland India.