6-3 Grasslands, Desert, & Tundra Areas with too little precipitation for large trees.

Tropical Savanna

Africa, west India, north Australia, parts of South America (pampas) Grasslands and savannas found in the interior of continents, bordering on deserts and temperate forests. Tropical biome dominated by grasses, shrubs, & small trees Rain falls during wet season (only time plants can grow) which lasts for only 2-4 months

Savannas, tropical grasslands, have very hot summers and cold winters. The temperature is usually between 10 degrees C and 35 degrees C. The soil in the savanna is generally a reddish color, porous, acidic, and has only a thin layer of the humus (made from the decomposition of plant and animal matter), and allows rapid water drainage. Large number of herbivores Tropical Savanna

Savannas usually receive between 20 and 50 inches of rain annually. About 7 months of the year are rainy. Around October there are thunderstorms and drying winds, which signals the beginning of the dry season. Fires are expected around January at the height of the dry season.

Tropical Savanna

Plants adapted to survive long period without water: plants lose leaves or die to ground Large horizontal roots Vertical leaves to reduce water loss Thorns to prevent being eaten

Animals: – Grazing herbivores migrate to follow rain to water holes – Give birth during rainy season (food most abundant) – Graze at different heights

Temperate Grasslands

Interior of continents with moderate rainfall, too little for trees Prairies (N. America), Steppes (Asia), veldt (S. Africa) & pampas (S. America) Mountains play a role in maintaining grasslands. Grasslands lie east of mountains. Fires from thunderstorms help maintain grasslands

Temperate Grasslands Plants: grasses & wildflowers. Shrubs & trees mainly on banks of streams

Temperate Grasslands

Plants: – Root systems form dense layers that survive drought and fire

Temperate Grasslands Most fertile soil – summer hot, winter cold. – Plants die back to roots – Low temperatures slow decomposition. Rate of decay slower than rate of addition of new vegetation. Organic matter accumulates in soil – Most grasslands converted to farmland.

Temperate Grasslands Animals: – Herbivores: large flat back teeth for chewing grasses

Temperate Grasslands Animals: – Many animals live in underground burrows to protect them from fire, weather, and predators

Temperate Grasslands Threats: – Farming & overgrazing. Grain crops do not hold soil as well as grasses, erosion occurs. – Grasslands changed to deserts.

Chaparral

Temperate shrubland found in all parts of the world with Mediterranean climate. Moderately dry, coastal climate in mid lattitudes (30 degrees N & S of equator) Little or no rain in summer

Chaparral Plants: – Low-lying, evergreen shrubs & small trees growing in dense patches (olive trees, scrub oak) – Herbs: sage & bay

Chaparral Plants have small leathery leaves that retain water. Leaves contain oil that promote burning Chaparral plants adapted to fire.

Chaparral Animals: – Camouflage is common adaptation

Chaparral Threats: – Human development. Near ocean, get a lot of sun, mild climate year round = hot property (Los Angeles)

Deserts

Plants: adapt to less than 10 inches of water/year – Adaptations to obtain & save water Succulents – thick, fleshy stems & leaves that store water

Deserts Plants: – sharp spines keep animals from eating their juicy flesh – Roots are shallow and spread out just under the surface – Many plants drop their leaves during dry periods – Brief growth spurts after a rare rain.

Deserts Animals: – Reptiles – thick, scaly skin prevents water loss – Amphibians – estivate (bury underground & sleep through dry period) – Many are nocturnal

Tundra

Location: northern arctic regions Winters too cold & dry for trees Deeper layers of soil stay permanently frozen,(permafrost) Topsoil thin. Low productivity In summer, topsoil thaws forming moist spongy bogs Free, non-frozen water scarce (limiting factor)

Tundra Bogs host mosquitoes & black flies, and birds.

Tundra Plants: low diversity – Mosses & lichens cover rocks in summer – Plants have wide shallow roots to anchor in thin soil against icy winds – Grow close to ground to help absorb heat from soil. – Woody plants (willow & birch) have dwarf forms or grow flat.

Tundra Animals: – Migratory birds breed here in summer – Caribou & moose migrate – Lemmings, mice, hares burrow during winter – Some animals change color and fur is well insulated

Tundra Threats – Most fragile biome – Foods chains simple, so easily disrupted – Conditions extreme, so land easily damaged & slow to recover – Human disruption new – oil exploration, extraction, transport, spills, leaks, pollution has poisoned food & water sources