Desert Flashcards
What is a key characteristic of Desert Climate?
Low rainfall
What are two facts about rainfall in desert climates?
- Rainfall is usually 1-10 in/yr. Always a moisture deficit.
- Scattered, unreliable, often intense rainfall events, erratic.
What is temperature like in Deserts and Steppes?
Temperature depends on latitude, so it can either be hot (subtropical) or cold (temperatre). Cold deserts are in the Northern Hemisphere
Look at the location of major deserts in the world
Look at the powerpoint!
What kind of climate are subtropical deserts?
Really Hot, no cold months.
If a desert has no cold months, what latitude is the desert?
Subtropical
What kind of climate are in mid latitude deserts
Higher seasonality w/ cold winter!
Know precipitaton/ temperature of different deserts!
Look at powerpoints!
What kind of deserts is snow relatively common?
Snow is relatively common in mid latitude or high elevation deserts
How much of the earth’s surface do deserts and steppes cover?
35% of the earth’s surface! They are also a large latitude range
What are the four major causes of aridity?
- Subtropical High
- Continentality
- Rainshadow
- Cold Currents
What is the subtropical high?
It is centered around 30 degrees. High and dry go to together! The east sides of the subtropical high is where there is a lot of build up of air (sinking air). East sides of the highs have more deserts.
What causes aridity in central Asia?
Continentality (being remote from water)
What deserts are influenced by continentality?
Great Basin, Sahara, Australian, and Gobi Deserts
How does the rainshadow affect case aridity?
Rainshadow - occurs anywhere there are mountains
How do cold ocean currents affect aridity?
Cold currents cause a surface temperature inversion so air cannot rise (or cool to dew point) so no rain. And STH!
What don’t you see in a satellite image of a desert?
- color- no green - vegetation
- clarity - few clouds, lack of moisture in atmosphere
- no signs of lakes or rivers
Why is Death Valley the driest place north of mexico?
- subtropcal high
- rainshadow of westerlies
- low elevation
all of these work together to cause aridy.
for test, she will give an example of a desert. know the factors that made it a desert!
Study!
What causes dunes?
When there is lots of wind and no vegetation to stabilize soil.
What is characteristic of the biome of a desert?
Relatively low biodiversity. Biomass is also very low.
What are 6 ways plants avoid desiccation in the desert?
Adaptation: two main strategies - store watera and reduce water loss/ drought avoidance
- Store water
- Put roots down deep where there is ground water
- Do not have leaves that transpire and lose water; instead have white hairs or spines that reflect radiation and provide shade
- wide spacing of plants means less competition for H20 and nutrients
- have long-lived seeds and an “ephemeral” existence allows plants to live and reproduce within a place with very patchy and inconsistent rainfall patterns
- Being deciduous, i.e., leafless most of the time, uses less water. Instead grow leaves only after a rain.
What is succulence?
Thick, fleshy, water-holding tissue
What are animal adaptations to aridity?
Two most important needs:
- avoid hypothermia
- adapt to low H2O intake
How do camels survive?
- Can go days without food and water because it is converted fat in the hump
- dry poops!
How do desert foxes adapt?
- Thick coat insulates from sun
- Lg. ear radiate heat away
- light color has high albedo
- reduce water loss.
- obtains all of the water they need from their food so they never drink water
How do kangaroo rats adapt?
- Nocturnal activity (cooler) and underground dens
- get water from seeds and feed
- specialized kidneys recycle water from their urine.
- waterless waste
What are the major desert crops in the U.S.?
cotton, nuts, citrus, grapes, and cattle
What are major human-environment interaction issues in desert?
Large scale irrigation for commercial crops depletes underground and above ground (there is very little of this) water supplies
Why grow stuff in the desert?
Lots of cheap land that noone does anything with anyway
What are many people want nice gardens doing instead?
Xeriscaping (using native plants).
what is a big water guzzler?
traditional lawns
Whats a good way to tell steppes and deserts apart?
Deserts - arid
steppe - semiarid
What is another big problem in deserts?
Habitat destruction and fragmentation from commercial agriculture and development
Why is habitat destruction and fragmentation bad?
Desert ecosystem is fragile!
Cactus rustling (stealing cacti) is a crime. Why are they so important?
Saguaros are keystone species. they provide nesting areas, perches, and food (fruit) for Gila woodpecker, flickers, martins, kestrels, and bats.
How does cattle ranching affect these habitats?
It makes many species endangered. They cause lots of erosion. Prevent plants from growing. Eat lots of grass by grazing
What is the estimated net proportion U.S. arid land grazed by livestock?
85%
