Succession

Question 1

1.

Answer 1

Pioneer plants that are tolerant of salt spray, lack of nutrients and water colonise bare sand. These plants e.g sea rocket, sea holly have xerophytic features such as sunken stomata to reduce water loss, small SA of leaves and thick waxy cuticle.

Question 2

2.

Answer 2

Pioneer plants change the conditions, allow sand to accumulate around them, forming little dunes, which provide more shelter for other plants to grow. Also, their dead leaves start to form humus which traps water and releases nutrients as it decays.

Question 3

3.

Answer 3

Sea couch grass colonises leeward sides of these new dunes. It’s underground stems stabalise sand and build higher dunes

Question 4

4.

Answer 4

Marram grass can then survive and this has extensive roots so further stabalising the sand and building dunes higher.

Question 5

5.

Answer 5

Nitrogen-fixing plants e.g birds foot trefoil colonise the base of the dunes, where more water is available. These ass nitrates to the newly formed soil.

Question 6

6.

Answer 6

This allows wider range of grasses to grow and the top of the dunes becomes grassland.

Question 7

7.

Answer 7

Eventually this may be succeeded by a woodland climax community. Woodland trees and shrubs out-compete the grassland plants by growing taller and shading them, and by having longer roots that can obtain more water and nitrates.