Distribution of gain and loss of the halophytic grassland in an area of 32,300 km2. Black spots show populations of G. flavomarginatus; dotted lines show distribution zones “A”, “B” and “C” of the species; the black line indicates the Mapimí Biosphere Reserve; dark grey color shows the zones with gain of halophytic grassland; light grey color shows the zones of halophytic grassland loss; medium grey color shows areas with grasslands that has been maintained; the grid make reference to squares of 100 km2 in the study area.