Desert Ecosystems Desert- an arid region with little or no vegetation Deserts in North America are located on the western side and run into Mexico. o Receive little or no water(less than 10 inches per year) o Are in a rain shadow of the mountains There are 4 main deserts in North America: 1.Great Basin Desert 2.Mojave Desert 3.Sonoran Desert 4.Chihuahuan Desert

1.Great Basin Desert Largest in North America (between Rocky and Sierra Nevada Mountains) Covers most of Nevada and parts of Utah, Oregon, and Idaho A cold desert because it is relatively high in altitude Most precipitation is in the form of snow fall – Not all of it melts into the ground because it evaporates in the spring Plants include: A.Sagebush- a desert bush; does not grow in salty areas B.Salt Bush- a desert bush; does grow in salty area – Plant in the same family such as spinach – Salty because the H ₂ O evaporates and leaves the salt behind.

Has playas- lakes that are temporarily dry for most of the year Deep soil on valley floor because of years of mountain erosion Other Plants and Animals Plains prickly pear cactus: grows low to ground Mormon tea Greasewood Blackbrush Snakewood, ect.

Animals- eat grasses and increase amount of sagebush Mule deer Pronghorn antelope Ecological Threats Introduction and spread of alien, invasive species cheat-grass brome

Mojave Desert Covers a wide range of vegetation types. Northern parts are like the Great Basin. The southern parts resemble the Sonoran Desert Contains “Death Valley” – Very hot – 4.3cm of rain per year Distinctive Features Yucca- huge plant that grows to tree like proportions Cacti- chollas & small cacti – Has to be frost tolerant because of snowfall and ice 250types of spring flowers – 80% of these only grow in the Mojave

Sonoran Desert Different types of soils because of the different types of rocks. Succulents can survive because there is no frost. Rain two times per year: – Long rains in winter – Downpours in summer. Bajadas- slopes where mountain erosion accumulates – Soils are deep and lots of plants grow on them – The loose soil holds an abundance of water Washes- rivers that carry water down from the mountains – Dry for most of the year yet the soil still remains moist

Chihuahuan Desert Over Northern Mexico and southern part of USA including west Texas and parts of New Mexico and Arizona At high altitude (1,000-1,500m) Summers are hot winter are relatively cool with night frost Rainfall is relatively high (20-30cm) – almost all in summer Nearly 80% has calcium rich soils because of lime stone – Indicates it was once under the ocean – Has small cacti and frost tolerate grasses Major Vegetation Low Areas – Creosote bush/ Tar bush Upper areas – Bajadas – Yucca (Spanish daggers – sharp leaves) High Areas – More bushes and small trees – H2O is more abundant in the valley floor

Highest True trees – Pines, oaks, junipers Microbes – Lichens, Fungi, Cyanobacteria General Desert Information Deserere comes from the word deserere( Latin for abandoned) A desert will form if the rate of precipitation is less than the rate of evaporation Not all deserts are hot, there are some in the polar regions Largest desert is the Sahara – Size of the US and stretches across north Africa Most of central Australia is desert Southern Africa has the Namib and Kalahari desert and Kalahari Bushmen Most desert are not sandy ( rocks,pebbles,and gravel) Dust Devils- Warm air rises quickly in an area and as it leaves, the other air rushes in to fill the space and carries sand with it.

Animals of the Desert Snakes Rattlesnakes Mojave rattlesnake Lives in the Mojave Desert Length 2-4 ft Is considered one of the most venomous snakes in the U.S. Venom is neurotoxin Western Diamondback Rattlesnake Range is Central/West Texas to Southern New Mexico/California Length 3-5ft but some can get as long as 7 Venom is hemotoxin

Animals Cont. Lizards – Gila Monster Range is the southwest US and Mexico Venom is a neurotoxin – Venomous spit Length – Up to 2 ft. Arachnids – Scorpion Venom is a neurotoxin Various species throughout the US – Tarantula Widespread through out the southwest US Can get 3-4 inches in size Can live 10 to 12 years

Hi Danny!