Sand Dunes

Question 1

What is a succession on sand called?

Answer 1

Psammosere

Question 2

What is succession, which is not interrupted by man, called?

Answer 2

Climatic climax vegetation

Question 3

What is the climatic climax vegetation in the British Isles?

Answer 3

Oak + Beech trees

Question 4

What plant colonises embryo dunes?

Answer 4

Pioneer plants

Question 5

How do Pioneer plants change the environment?

Answer 5

They grow upwards which interrupts saltation. This traps the sand and stabilises the surface

Due to their horizontal roots with rhizomes, they spread across the dune quickly. These attach and further stabilise the surface.

Adding humus to the soil which increases water retention + lowers pH. This helps other less resilient plants to grow

Question 6

What other pioneer plants are adapted to survive?

Answer 6

Sea couch
Marram

Question 7

What is a sea couch?

Answer 7

Has succulent leaves to store water

Question 8

What is marram?

Answer 8

Long roots that are able to extend down to the water table

Question 9

What happens to the sand on foredunes?

Answer 9

Further sand accumulation means that these are now at a height beyond the reach of the highest storm tides

Question 10

How much of the foredune is colonised and how much is exposed?

Answer 10

20% is exposed. 80% is cover in vegetation

Question 11

How does soil change as humus is added?

Answer 11

•The soil begins to darken
•The pH is lowered – slightly alkaline
•Most of the moisture is fresh water but it is still limited.

Question 12

How is humus formed?

Answer 12

As a result of plants dying and decaying

Question 13

What is the dune height in the embryo stage?

Answer 13

1 metre

Question 14

What is the dune height in the foredune stage?

Answer 14

5 metres

Question 15

What is the dune height in the gray dune stage?

Answer 15

8-10 metres

Question 16

What is the dune height in the blowout stage?

Answer 16

6-8 metres

Question 17

What are the features of embryo dunes?

Answer 17

80% exposed sand
Very little humus and moisture, mixed with salt and fresh water
The pH is over 8
Plant types are sand couch and Lyme grass

Question 18

What are the features of the foredunes?

Answer 18

20% exposed sand
Some humus, very little moisture, fresh water
The pH is slightly alkaline
Plant types are marram and xerophytic species

Question 19

What are the features of grey dunes?

Answer 19

Less than 10% exposed sand
More humus inland, low water content, fresh water
The pH increases inland, 6.5-7
Plant types are creeping fescue, sea spurge, some marram, cotton grass and heather

Question 20

What are the features of blowouts?

Answer 20

Over 40% exposed sand on dunes
High humus and brackish water in slacks
The pH is 5-6
Plant types are heather, gorse on dunes , juncus in slacks

Question 21

Why are grey dunes called fixed dunes?

Answer 21

They’re the most stabilised as they’re over 90% colonised and covered in vegetation.

Question 22

The moisture content in fixed dunes is high. True or False

Answer 22

False, it’s low

Question 23

What is succession when interrupted by man called?

Answer 23

Plagioclimax