Vegetation Flashcards
(13 cards)
importance of stabalisation
Vegetation is important in stabilising sandy coastlines through dune successional development on sandy coastlines and salt marsh successional development in estuarine areas.
How does vegetation increase the rate of sediment accumulation
Plant stems and leaves interrupt the flow of wind and water, reducing their velocity and encouraging deposition.
When the vegetation dies it adds its organic matter (hummus) to the soil.
Pioneer Plants
These are the first plants to colonise freshly deposited sediment.
They modify the environment:
Stabilising sediment
Adding organic matter that retains moisture, contributes nutrients and provides shade.
Reduce evaporation in sand.
What makes the coast a harsh environment for plants?
They’re exposed to high wind speeds at low tide.
They’re submerged in salty water for half the day.
The evaporated sea spray makes the sediment saline.
Plant succession
he changing structure of a plant community over time as an area of initially bare sediment is colonised
Xerophytic plants
specially adapted to dry conditions to colonise bare sand.
psammosere
Plant succession on sand
When do Embryo dunes form?
when seaweed driftwood or litter provides a barrier or shelter to trap sand.
As the embryo grows, it is colonised by xerophytic pioneer plants, like sea couch grass, lyme grass, saltwort and sea rocket.
the embryo dunes alter the conditions to something other plants can tolerate, allowing other plants to colonise and forms a fore dune
Adaptions of Marram grass
has waxy leaves to limit water loss through transpiration and resist wind-blown sand abrasion.
has roots that can grow to 3m to reach down the water table and the stem can grow 1m a year to avoid burial by deposited sand.
allows the dune to grow, rapidly forming a yellow dune
it’s called this because the surface is mainly sand, not soil
What happens when marram grass dies?
it adds hummus to the sand, creating soil
Halophytic plants
are specially adapted to saline conditions to colonise mud.
Halosere plants
plant succession in salty water.
Estuarine areas are ideal for salt marshes because…
they’re sheltered from strong waves (so sediment like mud and silt can be deposited)
rivers transport a supply of sediment to the river mouth, which may be added to by sediment flowing into the estuary at high tide
