3.5

Question 1

What is a seral community?

Answer 1

A biological community developed through succession of a habitat

Question 2

What is a psammosere?

Answer 2

Seral community in sand dunes

Question 3

What is a halosere?

Answer 3

Seral community in salt marshes

Question 4

What is a dune slack?

Answer 4

• A dune that has been eroded by the wind
• Eroded until water table as wet sand is hard to erode via wind

Question 5

How are embryo dunes formed?

Answer 5

Sand is blown, collects in places sheltered by wind

Question 6

What type of plants are the first in a seral community?

Answer 6

Pioneer species
- xerophytic in psammosere
- halophytic in halosere

Question 7

Adaptations of plants in halosere?

Answer 7

Are salt tolerant

Question 8

Adaptations of plants in psammosere?

Answer 8

• tough, long flexible leaves
• little water loss (transpiration)
  Fast growing (1m/year)
  Tolerate temperature up to 60°C

Question 9

What is the pioneer species in psammoseres?

Answer 9

Marram Grass

Question 10

What is the pioneer species in haloseres?

Answer 10

Algae - grows on mudflats
Cordgrass - colonises area

Question 11

How do haloseres form?

Answer 11

• clay and silt deposit in low energy environments, form mudflats, deposition of silt by tides and from rivers
• pioneer species colonise intertidal areas, trap sediment in roots, stabilise mudflats
• organic matter is added when pioneer species decompose
• other species grow above high tide mark, less inundation, trap more sediment
• soil develops due to increased nutrient content
• salt marsh is more stable due to more plants

Question 12

How are psammoseres formed?

Answer 12

• embryo dunes are inhabited by pioneer species
• sand is carried further up beach by onshore winds, is deposited when obstacles are met
• pioneer species’ roots stabilise dune, reduce wind speed, add organic matter to dune on decomposition
• other species start to grow, trap more sand, form foredune
• mature dunes form
• periods of erosion create dune slacks

Question 13

What are mature dunes?

Answer 13

• Dunes with developed soil with good nutrient and water availability
• allow a greater range of plants to grow
• are more stable dunes

Question 14

What are yellow dunes?

Answer 14

• Largest dunes
• are mostly covered by marram grass