coastal veg

• what do plants do to unconsolidated material

  plants can stabilize unconsolidated material and protect it from erosion
• how do plants make unconsolidated material harder to erode?

  plant roots bind the sediment particles together which makes it harder to erode
• how do plants protect from wave/wind erosion?

  plant stems and leaves which cover the grounds surface protect sediment from wave/wind erosion
• what does vegetation increase the rate of

  sediment accumulation

  - plant stems and leaves interrupt the flow of water/wind which reduces their velocity/energy and encourages deposition
• what is humus


  dead organic matter
• why is the environment harsh at the coast

  the sediment is sand, clay or silt which is harsh for plants

  - there is a high wind speed at low tide

  - lack of shade causes a high diurnal (day) temperature

  - plants will be submerged in salt water of part of a day

  - sediment is highly permeable so water drains quickly = no fresh water

  - submerged sediment has pores which are filled with salt water and not oxygen so the plant can't respire

  - sand lacks nutrients
• what plants are adapted to dry conditions (sandy coasts)

  xerophytic

  - these can colonize on sand
• what plants are adapted to saline conditions (muddy estuarine coasts)

  halophytic plants

  - these can colonize on mud
• what are the first plants called in plant sucession

  pioneer plants (ones that first colonize an area)
• what do pioneer plants do to the environment

  they modify the environment by

  - stabilizing sediment

  - adding humus/organic matter which retains moisture and nutrients

  - provide shade which reduces evaporation of water in sand
• what is the impact of pioneer plants

  after modifying the environment, they allow less hardy plants to colonize the area which in turn adds more humus and therefore more less hardy plants can grow
• what is plant succession on sand

  psammosere
• dune development in plant sucession

  👶 embryo dune - formed when seaweed, driftwood or litter provides a barrier which traps sand.

  
  

  🏌️‍♂️ fore dune - formed as an embryo dune grows due to colonization by pioneer plants

  
  

  💛 yellow dune - dune surface remains mainly sand not soil but begins to develop soil underneath

  
  

  🌪 grey dune - with the added humus and soil the dune is now higher than the high tide line + rain water can now wash out salt water from the soil

  
  

  🌲 terrestrial/climax - deeper soils where larger plants such as trees can grow
• plants in plant sucession

  👶embryo dune/fore dune - sea couch grass, sea rocket

  💛yellow dune - marram grass

  🌪 grey dune - gorse bush

  🌲terrestrial/climax - hazel, bramble, oak
• what is plant succession in sediment in salty water

  halosere
• sediment stages in the halosere

  mud flat - mixing of fresh water and sea water in estuary causes clay particles to stick together & sink, algae colonizes this and causes more mud and clay to bind together, this thickens the sediment

  
  

  low marsh - is covered by the high tide everyday but not necessarily by low tide

  
  

  high marsh - when sediment has continued to build up on a low marsh so the marsh is only covered by spring tides, exposed out of the tide so rain water washes the salt out of the marsh which means other plants can colonize

  - it is at this point where creeks form, rivers flowing through marshes to the sea

  
  

  terrestrial climax - sediment continues to build up and rise out of the water until it supports a woodland
• plant succession in the halosere

  mud flat - algae

  
  

  low marsh - cord grass

  
  

  high marsh - sea lavender

  
  

  terrestrial - oak trees