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Flashcards in Vegetation and coast stabilisation Deck (18)
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1

How are sand dunes made?

Wind blown sand stabilised by plant succession

2

What is the first stage of plant succession?

Bare ground is gradually colonised by plants called 'pioneer species'

3

What is the second stage of plant succession?

Pioneer species modify the environment by binding sand or mud with their roots and add nutrients when they die and decay

4

What is the third stage of plant succession?

Creeping plants with leaves keep moisture in the sand/ mud, these changes allow other species to colonise

5

What is the fourth stage of plant succession?

The new plants modify the environment by providing shade and improving the soil

6

What is the fifth stage of plant succession?

As the environment changes, different species colonise until it becomes stable

7

What is the sixth stage of plant succession?

The final community to colonise is the climatic climax community (trees)

8

Describe embryo dunes

Small scattered patches of marram grass which are largely self-seeded or growing from rhizomes up to 3m long. Only pioneer species can cope with the adverse conditions

9

Describe mobile (yellow) dunes

Some large areas are bare, moving sand but greater cover of marram grass

10

Describe semi-fixed (grey) dunes

Smaller patches of bare sand tinted grey with many plants besides marram grass

11

Describe fixed dunes

Almost complete vegetation cover, marram grass is sparse in isolated clumps before ultimately disappearing whilst many other species are present

12

Describe dune slacks

Sand becomes eroded so the water table can be reached so forms a damp depression prone to flooding in the winter. Large numbers of rabbits keep the vegetation short but cause damage in blow-outs where bare sand is exposed

13

Describe climax

Sand dunes generally develop into shrub and then woodland

14

What are halophytes?

Plants that can tolerate saline (salty) conditions

15

What are salt marshes?

Areas of flat, silty sediments that accumulate around estuaries or lagoons

16

Where do salt marshes develop?

- In sheltered areas where deposition occurs
- Where salt and fresh water meets
- Where there are no strong tides or currents to prevent deposition or accumulation

17

As mudflats develop (1) tolerant plants such as eelgrass begin to colonise and (2) the land. Halophytes such as (3) slow down (4) to trap more mud and silt. As sediment accumulates the surface becomes (5) and (6) start to colonise

Salt
Stabilise
Codgrass
Tidal flow
Drier
Different plants/ sea asters

18

What are creeks?

Created by water flowing across the estuary at low tide to divide up the salt marshes