An increase in some small animal populations has led to some grasslands being degraded.[1] These animals include the Himalayan marmots, the Brandt’s and plateau vole, and the plateau pika and zokor.[2] They damage this environment mainly through their burrowing into the ground and gnawing at the grass and other plants.[5][9] Both of these actions encourage soil erosion and make it more difficult for plants to firmly ground themselves to this poor terrain.[5] Hence grass has a tougher time growing and the terrain becomes spottily doused with grass.[5] However, there are those who do not think that these animals contribute to grassland degradation.[5] They claim that such burrowing aids in the recycling of nutrients in the soil and that the rise in population is only normal since grazing levels in these areas have also risen.[5][9]