Environmental concerns regarding savannas are poaching, overgrazing and clearing of the land for crops. Overgrazing, ploughing, and excess salts left behind by irrigation waters have degraded such areas. Strong winds blow loose soil from the ground after ploughing, especially during droughts.
The periodic precipitation of grasslands varies seasonally and annually. Temperate grasslands average between 250 and 750 mm of rain each year, while tropical and subtropical grasslands have an annual precipitation rate of between 500 and 1,500 mm. The amount of rainfall determines the nature and extent of grassland inhabitants and soil formations. Periods of drought are common and often prolonged, having an adverse effect on species development, particularly in the warmer climates.