Vegetation and coast stabilisation

Question 1

How are sand dunes made?

Answer 1

Wind blown sand stabilised by plant succession

Question 2

What is the first stage of plant succession?

Answer 2

Bare ground is gradually colonised by plants called ‘pioneer species’

Question 3

What is the second stage of plant succession?

Answer 3

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

Question 4

What is the third stage of plant succession?

Answer 4

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

Question 5

What is the fourth stage of plant succession?

Answer 5

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

Question 6

What is the fifth stage of plant succession?

Answer 6

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

Question 7

What is the sixth stage of plant succession?

Answer 7

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

Question 8

Describe embryo dunes

Answer 8

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

Question 9

Describe mobile (yellow) dunes

Answer 9

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

Question 10

Describe semi-fixed (grey) dunes

Answer 10

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

Question 11

Describe fixed dunes

Answer 11

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

Question 12

Describe dune slacks

Answer 12

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

Question 13

Describe climax

Answer 13

Sand dunes generally develop into shrub and then woodland

Question 14

What are halophytes?

Answer 14

Plants that can tolerate saline (salty) conditions

Question 15

What are salt marshes?

Answer 15

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

Question 16

Where do salt marshes develop?

Answer 16

• 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

Question 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

Answer 17

Salt 
Stabilise 
Codgrass 
Tidal flow 
Drier
Different plants/ sea asters

Question 18

What are creeks?

Answer 18

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