Any extensive area of tussock grassland is located in the rain shadow of the New Zealand Southern Alps on the South Island's south and eastern side. New Zealand is comprised of every biome except desert and the tussock grasslands occur in the driest area of the Island. The tussock grasslands are divided into two parts, the Canterbury in the southern end and the Otago in the northern portion. The two areas have some similarities in climate, but the Otago is much drier rarely receiving more than 500 mm (20 in) a year in the driest sections. Both tall and short tussock grass species exist in these grassland areas.