Thorn scrub vegetation surrounds the Thar Desert of India and Pakistan and extends south and east following the Himalayan Mountains in Nepal. Vegetation in this ecotype ranges from dense, shrub-like trees to open thorn savanna. Human impact on the vegetation is believed to be high like many other woodland-savanna systems in Eurasia with many ecologists believing this area to represent a degraded state of tropical dry forest. The tallest grasslands in the world exist here, interspersed with savanna and scrub, and support a wide variety and density of wildlife species.