Salt Marshes

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  • Salt Marshes
    • Halosere
    • Salt marshes only form in low energy environments where there is shelter from the wind and waves
    • The most likely place along a coastline where you’ll find this sort of sediment input is near a tidal flat.
      • The low gradient of a tidal flat means that any rivers that flow into it will very quickly deposit any sediment they’re transporting
    • Over time, sediment accumulates and the elevation of the tidal flat increases in a process known as coastal accretion.
      • This reduces the duration of tidal flooding allowing a small selection of plants to grow on the now developing salt marsh. These plants are halophytic.
    • 1. Early stages in the development of a salt marsh.
      • Extremely sheltered, river estuary to encourage sedimentation (behind a spit) to create a mudflat.
    • 2. Pioneer stage.
      • Mudlfats colonise by pioneer species such as glass wort (halophytes). They trap more mud, dying plants add humus and nutrients to the soil making the conditions less hostile.
    • 3. Establishment stage.
      • Species like Sparta growing, Muddy shore spends more time emersed. Conditions become more hospitable for more plants, a variety of species start to colonise and grow. More species, less bare ground.
    • 4. Competition stage.
      • Plants need water, light and CO2. They compete for resources in the same area with lots of plants. New plants that grow quick and die young , stronger plants dominate. Number of species continue to increase as abiotic factors become more favorable.
        • Opportunistic species- vast number of offspring, spread far and wide.
        • Equilibrium species- More energy and log lasting structures. Not widely dispersed.
    • 5. Stabilisation stage.
      • Assemblies of dominant and successful species. Fewer changes occur, height has increased, immersed less frequently. Few (if any) species added. Expected species include: scurvy grass and sea lavender.
    • 6. Climax stage.
      • Only immersed on exceptional tides, maybe 1 or 2 times a year. Fresh water influences the back of the marsh- forms a freshwater marsh, then into a scrub and finally into a forest. Plagioclimax.

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