Grasslands – 20-50” annual rain, but usually on the lower side of that. (VERY generalized map) Note: tropical savannas ARE grasslands.

Some Properties?

Properties Rainfall is the most significant limiting factor. Desert rain<Grassland rain<Forest rain. Organisms must tolerate droughts and wildfires. The fires also limit tree growth. Grasslands are varied and hard to classify. Soil is bound by vast horizontal root networks (unless cultivated).

Categories – Tropical, Temperate, and Polar (Tundra) Tropical (savanna): higher avg temps with low to moderate precipitation and a prolonged dry season. Temperate: bitterly cold winters with hot, dry summers. Precipitation is sparse and random. Therefore… Thin layer of humus (organic component of the soil from partially decomposed plant or animal tissue) Overall, the temps of the grasslands as a category have a range from 0 o F to 90 o F.

Plant Adaptations During a fire, while above-ground portions of grasses may perish, the root portions survive to sprout again Some prairie trees have thick bark to resist fire Prairie shrubs readily resprout after fire Roots of prairie grasses extend deep into the ground to absorb as much moisture as they can Extensive root systems prevent grazing animals from pulling roots out of the ground Prairie grasses have narrow leaves which lose less water than broad leaves Grasses grow from near their base, not from tip, thus are not permanently damaged from grazing animals or fire Many grasses take advantage of exposed, windy conditions and are wind pollinated Soft stems enable prairie grasses to bend in the wind

Animal Adaptations Some animals, such as bison, have broad, flat- topped teeth and digestive systems especially adapted to feed on grasses. The animals have adapted by migrating, hibernating, or burrowing. Many prairie animals have front legs and paws that allow them to burrow into the ground, where they are protected from predators. Many prairie animals are adapted for nocturnal life; that is, they are active at night, which helps conceal their presence from predators. The color of many animals blends in with the plant life, which also helps them hide from predators. Grazers compared to browsers. Resource partitioning!

Tropical Grasslands (Savannas) Some Properties?

Tropical Grasslands (Savannas) Cover almost ½ of Africa. Warm or hot with 20-50” annual rain. Require long periods of drought or else they become tropical forests. May-October is the dry season and life explodes when rain resumes.

Temperate Grasslands Some Properties?

Temperate Grasslands Steppes (have short bunchgrasses) of central Europe, prairies or plains (sod- forming grasses) of the US, pampas of S America, veldts of South Africa. Less rainfall than savannas. Can be less than 20” annual rain up to 30”. Rains in late spring/early summer. Plants use wind to pollinate. Therefore they may spread quickly.