Desert-grassland boundaries can change as a result of

temperature

precipitation

invasive trees

habitat loss

Precipitation

Grasslands are characterized as lands covered by grasses rather than large shrubs or trees. Grasslands are found in regions which receives rainfall that are not enough for the growth of forests. Desert covers about one fifth of the Earth's surface and occur where rainfall is less than 50 cm/year. Rainfall are least frequent in deserts as compared to grassland. The desert-grassland boundaries can change as a result of precipitation. The fate of land form of boundary will be dependent upon precipitation. As, if the boundary receives moderate or sufficient rainfall to grow vegetation then it will be included in the grassland and if the boundary receives no or scanty rainfall then boundary will be included in desert region.

explanation:

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.