Grassland

The grassland develops in the areas, set at mid-latitude, in which there is not enough humidity to form forests but not so arid in the dry season to be prevent the growth of vegetation. The climate to which this form of vegetation is tied is characterized by cold winters and hot, dry summers, with scarce and irregular precipitations. Among the characteristic of the grasslands are the frequent fires and pasture for livestock or wild animals, two factors which are also determined by the predominantly grassy vegetation of this biome. In fact, graminaceae have the ability to grow much quicker than woody plants after a fire or after grazing by a herd of herbivores. The graminaceae are the prevailing vegetable family of the grasslands, generally mixed with other grassy plants, such as, in the humid regions, numerous kinds of wild flowers. Trees and bushes grow only potentially along the banks of bodies of water or in the areas of transition between humid grassland and moderate forest. The vast extensions of grasslands in the northern hemisphere are situated in North America (the so-called Great Plains) and in Russia. In the United States of America the climate becomes increasingly arid towards the west: it goes from the luxuriant grasslands of the east, characterized by vast expanses of grassy plants, to the wide and arid plains of the west, where the vegetation is constituted by low scattered bushes. In Asia the situation is the opposite: it goes from the grasslands of eastern Europe, which are similar to those of the east of North America, to the dry steppes of Kazakhstan and Mongolia, that resemble instead those of the west of the United States. The land above sea level found in the moderate band of the southern hemisphere are much less wider than those situated in the northern hemisphere, and accordingly there are few vast extensions of grassland in this area. The most important are the pampas of Argentina and Uruguay. Unlike the greater part of the steppes and grasslands, which are generally formed in the inner part of the continents, the pampas extend along the coastal areas of the Atlantic ocean. The factors that favour the growth of the grassy plants in these regions are the semiarid climate together with the flat territory, characterized by little drainage. Other grasslands and steppes of the south hemisphere are found in southeast Australia, in the basin of the river Murray, in some zones of the New Zealand and in South Africa, in the High Veldt (northern Karroo).

Guido Bissanti