Flashcards in KQ2 - Why are hot arid / semi-arid environments considered to be ‘fragile’? Deck (34)
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1
how does wind make arid areas fragile
Strong winds and shifting sand create unstable surfaces that make it difficult for vegetation to grow
2
roots of plants in arid
shallow to grab immediate rainfall or deep to find underground water
3
size of plants like in arid / semi-arid areas?
Size: tend to be small and sparse
4
size of animals like in semi-arid / arid areas?
small to reduce water loss and maximise heat loss e.g. gerbil
5
Where is Arches National Park
SE Utah, USA
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How many visitors visit the park annually?
1 million
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How much rain does Arches National Park receive?
230 m annually
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How many stone arches does Arches National Park have?
less than 2000
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eg of Flora in arches national park
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
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how does lack of veg make arid areas fragile
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
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how does evaoporation make arid areas fragile
High evaporation from rain, runoff and groundwater makes soil saline
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how does soil quality make arid areas fragile
Hard, salty crusts impede root growth
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how does lack of precipitation make arid areas fragile
Soils are thin and infertile because lack of precipitation limits chemical weathering processes
14
how does drought/lack of water make arid areas fragile
Animals and plants suffer when exposed to long periods of drought
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how does wind affect eco systems
Strong winds and shifting sands create unstable surfaces that make it difficult for vegetation to become established.
16
what is cryptobiotic soil?
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.
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where is cryptobiotic soil found
arches national park, utah, usa
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plant stems in arid
Stems: store water e.g. cacti
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leaves in arid
small and waxy or thorns to reduce water loss and protect plant. Leaves may die off in dry season
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reproduction in arid plants
often very bright flowers to attract the few pollinators. Use wind or animals to spread their seeds
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stomata of arid plants
stomata closed in day to lower evapotranspiration
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what is CAM
crassulacean acid metabolism (CAM) which allows them to photosynthesise when close their stomata
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habits of arid animals
nocturnal, hibernate in dry season or burrow to restrict water loss
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colour of arid animals
light to reflect heat and blend into background sand/dust e.g. camel, fennec fox
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heads/holes of arid animals
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
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excretion of arid animals
highly concentrated urine and faeces to reduce water loss
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physical factors affecting arches and making it vulnerable
temperature
bedding planes in sandstone
weathering
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human factors affecting arches and making it vulnerable
OVR use
walking on cryptobiotic crust
poulltion (air noise water)
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why is WIND making Arches National Park vulnerable?
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
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