Mudflats and saltmarshes (halosere sucession)

• What are the initial conditions needed

  • Mudflats form as a result of a process called flocculation
  • The salt water then mixes with the slow moving water of the estuary that carries lots of suspended sediment
  • This causes flocculation
  • The saltwater flows gently into the estuary
  • Mudflats develop on sheltered shorelines that aren't exposed to powerful waves- associated with low energy environments such as estuaries & in the landward side of spits
• What is the development of the mudflat

  • Once a mudflat has been formed, it can be colonised by specific halophytic (salt tolerant) plants
  • Pioneer species (can survive in harsh conditions)= grasswort, eel grass and cord grass
  • To survive on mudflat, pioneer species must be able to live in high salt content conditions
  • Upper parts also help trap sediment and roots help further consolidate the mud by trapping it
• From lower saltmarsh to upper saltmarsh

  • These species are less specialised and therefore can colonise the area quickly
  • They are able to survive bc the middle/upper marsh is inundated by sea water less often and has a higher level of nutrients as a result of the pioneer species decaying
  • examples: sea lavender, saltmarsh grass and sea aster
• Climatic climax vegitation


  • The process of going from a mudflat to a woodland is called succession
  • Ecological succession is the process by which the mix of species and habitat in an area changes overtime. Gradually, these communities replace one another until a 'climax community' like a mature forest is reached
• What is a Climatic climax vegitation

  • Once a saltmarsh has established, it can develop into the climatic climax vegetation. This is the vegetation that an area would develop into if left, it differs depending on the climate of the area. For UK, this is mixed oak woodland
• Why don't most saltmarshes develop into climatic climax vegetation

  Most saltmarshes in UK are managed so don't reach this stage. Many saltmarshes are nature reserves or are prevented from reaching climatic climax by coastal defences. This is called a plagoclimax
• What is flocculation


  When the sediment particles come out of suspension and clump together to form a floc. In the formation on a mudflat, this happens as a result of tje suspended load mixing with saltwater
• What is a creek

  • Creeks through saltmarsh form in a similar manner to rivers. They help the tidal water drain away from the saltmarsh by taking the easiest route.
  • As these creeks are still salt water, pioneer species can be found on their banks
• What are salt pans

  • Salt pans form where there is a depression or a lack of plant in a small area of the saltmarsh. Tidal water collects here with a salt content that increases as the trapped water evaporates
• What is an example

  • Most of the area behind Spurn Head has developed into a mudflat with a small proportion progressing through the halosere succession to become a saltmarsh
  • Most mudflat don't develop into saltmarshes bc of the specific conditions needed for this to occur e.g halophylic plants need to colonise the mudflat, storms need to not destroy the system