Importance of Tightly Coupled Equations in Modelling Grassland Ecological Economics

The research reported by Mathur and Sharma (2018), referred hereafter as M&S, analyses the interactions between ecology and economy of the Banni grassland, located in the district of Kachchh, Gujarat, through a system dynamic model factoring in area covered by the invasive mesquite Prosopis juliflora (mesquite-covered area, hereafter MCA, Ap in M&S) and the incomes from livestock and mesquite. M&S has, however, overlooked the previous work on economy-ecology linkages of the region (Geevan et al 2003, 2005). Certain selections from the Geevan et al study, the discussion on system dynamics modelling framework, were published by INSEE as a book chapter (Sengupta and Bandyopadhyay 2005). While M&S has cited Geevan et al (2003) several times, its system dynamics model, which is central to the work, was overlooked. This oversight seems to have led to several flawed formulations in M&S. We briefly point out these.