Definition: A plain without trees (apart from those near rivers and lakes); it is similar to a prairie, although a prairie is generally considered as being dominated by tall grasses, while short grasses are said to be normal in the steppe. It may be semi-desert, or covered with grass or shrubs or both, depending on the season and latitude.
Definition: Monthly PET (Potential Evapotranspiration Rate) within the geographic range of a taxon. Evapotranspiration (ET) is the sum of evaporation and plant transpiration from the Earth's land surface to atmosphere. Potential evapotranspiration (PET) is a representation of the environmental demand for evapotranspiration and represents the evapotranspiration rate of a short green crop, completely shading the ground, of uniform height and with adequate water status in the soil profile. It is a reflection of the energy available to evaporate water, and of the wind available to transport the water vapour from the ground up into the lower atmosphere.