KQ2 - Why are hot arid / semi-arid environments considered to be ‘fragile’?

Question 1

how does wind make arid areas fragile

Answer 1

Strong winds and shifting sand create unstable surfaces that make it difficult for vegetation to grow

Question 2

roots of plants in arid

Answer 2

shallow to grab immediate rainfall or deep to find underground water

Question 3

size of plants like in arid / semi-arid areas?

Answer 3

Size: tend to be small and sparse

Question 4

size of animals like in semi-arid / arid areas?

Answer 4

small to reduce water loss and maximise heat loss e.g. gerbil

Question 5

Where is Arches National Park

Answer 5

SE Utah, USA

Question 6

How many visitors visit the park annually?

Answer 6

1 million

Question 7

How much rain does Arches National Park receive?

Answer 7

230 m annually

Question 8

How many stone arches does Arches National Park have?

Answer 8

less than 2000

Question 9

eg of Flora in arches national park

Answer 9

Yuccas: drought resistors; spines and hairy leaves which reduce exposure to air currents and solar radiation … limiting water lost to evapotranspiration; long taproots that can reach water beyond the reach of other plants

Question 10

how does lack of veg make arid areas fragile

Answer 10

Lack of vegetation exposes the soil to wind and water erosion
Without vegetation, little organic matter is created that would normally decompose to release plant nutrients

Question 11

how does evaoporation make arid areas fragile

Answer 11

High evaporation from rain, runoff and groundwater makes soil saline

Question 12

how does soil quality make arid areas fragile

Answer 12

Hard, salty crusts impede root growth

Question 13

how does lack of precipitation make arid areas fragile

Answer 13

Soils are thin and infertile because lack of precipitation limits chemical weathering processes

Question 14

how does drought/lack of water make arid areas fragile

Answer 14

Animals and plants suffer when exposed to long periods of drought

Question 15

how does wind affect eco systems

Answer 15

Strong winds and shifting sands create unstable surfaces that make it difficult for vegetation to become established.

Question 16

what is cryptobiotic soil?

Answer 16

Cryptobiotic soil, small ecosystems on top of the desert floor, die under any vertical pressure. They form a ground cover just a few cm thick.

Question 17

where is cryptobiotic soil found

Answer 17

arches national park, utah, usa

Question 18

plant stems in arid

Answer 18

Stems: store water e.g. cacti

Question 19

leaves in arid

Answer 19

small and waxy or thorns to reduce water loss and protect plant. Leaves may die off in dry season

Question 20

reproduction in arid plants

Answer 20

often very bright flowers to attract the few pollinators. Use wind or animals to spread their seeds

Question 21

stomata of arid plants

Answer 21

stomata closed in day to lower evapotranspiration

Question 22

what is CAM

Answer 22

crassulacean acid metabolism (CAM) which allows them to photosynthesise when close their stomata

Question 23

habits of arid animals

Answer 23

nocturnal, hibernate in dry season or burrow to restrict water loss

Question 24

colour of arid animals

Answer 24

light to reflect heat and blend into background sand/dust e.g. camel, fennec fox

Question 25

heads/holes of arid animals

Answer 25

often large ears for cooling by dissipating excess heat as blood vessels are close to surface (fennec fox = 6 inches), second eyelids to keep out sand, camel can close nostrils to keep out sand

Question 26

excretion of arid animals

Answer 26

highly concentrated urine and faeces to reduce water loss

Question 27

physical factors affecting arches and making it vulnerable

Answer 27

temperature
bedding planes in sandstone
weathering

Question 28

human factors affecting arches and making it vulnerable

Answer 28

OVR use
walking on cryptobiotic crust
poulltion (air noise water)

Question 29

why is WIND making Arches National Park vulnerable?

Answer 29

Wind blows broken up crust away, preventing reattachment to disturbed areas, as well as disrupting the underlying loose soil, often covering nearby crusts +slow rates of recovery

Question 30

why are BEDDING PLANES making Arches National Park vulnerable?

Answer 30

lines of weakness

Question 31

how is TEMPERATURE making Arches National Park vulnerable?

Answer 31

Temperatures fall below 0˚C for 7 months/yr so freeze-thaw and crystal salt weathering takes place

Question 32

how is WEATHERING making Arches National Park vulnerable?

Answer 32

Cracks widened by crystallisation

Question 33

how are HIGH TEMP and LOW PRECIPITATION making Arches National Park vulnerable?

Answer 33

High evapotranspiration rates and low irregular rainfall severely limits opportunities for plant growth. Water is often lost from the soil as there is little excretion so the organic content of the soil may only be 0.5-2.0%, so is … poor at retaining water and nutrients

Question 34

what is the FAUNA like in arches national park

Answer 34

Mule deer: nocturnal so most active at night so avoid harsh temperatures and cope with large diurnal range; good visibility to locate food