Land Degradation and Restoration Driven by Invasive Alien –Prosopis Juliflora and the Banni Grassland Socio-Ecosystem (Gujarat, India)
Land Degradation and alien species invasions gained significant attention of the scientific community and the intergovernmental establishment. This review presents a case in which these two processes jointly interact with an ecosystem – the Banni grassland – and its users over six decades. Banni is an arid, yet productive rangeland that supports a pastoral community raising grass-cover-dependent livestock. A bush/tree alien species, Prosopis juliflora, initiated a land degradation process by out competing the grass-cover species, thus undermining the pastoral livelihood. Rather than yield to the prevailing approach of eradicating an invasive species, the community and authorities considered cultural, scientific, and policy issues, and worked together to initiate linked processes of the invasive species naturalization and the grassland ecosystem transformation, to a mosaic of grassland and bush/tree woodland patches ecosystem. The woody biomass of the invasive bush/tree patches, sustainably harvested and manufactured to charcoal, offsets the loss of the partially removed grass cover, thus fully restoring the land’s biological productivity and diversifying the pastoralists’ livelihood. Lessons learned from the Banni grassland’s socioecosystem dynamics, first degraded and then restored by alien invasion, are detailed using the conceptual framework of biodiversity and ecosystem services. Two algorithms, for calculating income of harvesting the Prosopis land cover biomass, and for projecting the human population size to be sustainably supported, can be used as guidelines for achieving sustainable land use in similar circumstances.
