Now, large herds dung and urinate all over their own food, and they have to keep moving, and it was that movement that prevented the overgrazing of plants, while the periodic trampling ensured good cover of the soil, as we see where a herd has passed.
大量的兽群在自己的食物上大小便， 而它们又必须不断的迁移， 这些迁移过程 防止了过渡放牧的现象， 同时定期的踩踏土壤 正如这群动物路过时发生的那样 确保了土壤表面得到了很好的覆盖。