The Shortgrass Prairies in North America - Research Paper Example

The climate in the Northern grasslands varies from continental in the central region to the Mediterranean in the California and Palouse region and to dry subtropical in the desert region. The grasslands have wet and dry seasons with precipitation and temperature extremes. The winters in the Great Plains are severe, dry and windy with little snow, the spring season being moist and summer being droughty with thunderstorms. About two-thirds of North American precipitation falls in the growing season except in California and Palouse region.

The vegetation in the grassland is supported by little or no amount of rainfall in the late growing season (Sims and Risser, 2000).The seasonal movements of the air and the dynamics create a greater range of climates than in any other biome of North America. The cold arctic air in winter and the frequent incursions of tropical air in summer create wide temperature extremes and low humidity in the region (Sims and Risser, 2000).The climate of the grassland follows a north-south and east-west pattern.

It has been noted that as the precipitation and relative humidity decreases, the radiation of the sun, amount of rainfall, water stress and potential evaporation increases from east to west. As the air temperature, the number of frost-free days, evapotranspiration, precipitation increases in summer, the solar radiation increases from north to south. Northeast and southwest precipitation gradient is observed in the grasslands. Mean annual air temperature in the short grassland ranges up to 15 C, whereas the annual precipitation is up to 30cm.

Evaporation is greater than precipitation except in the tallgrass region. The growing season in the shortgrass prairie averages 193 days compared to 270 days in the southern plains short grass prairie (Sims and Risser, 2000).Johnson (2001) states that short grass prairies are the driest in North America, and their dryness is due to the long periods of drought and hot weather. Most of the rain coming from the Pacific Ocean is stopped by the Rocky Mountains, which add to the region's dryness. It is also one of the main reasons for the dry climate of the region.