Ecology trip

Question 1

Where do sand dunes form?

Answer 1

above the intertidal zone where specialised plants trap sand and build dunes over time

Question 2

When does sand dune formation begin?

Answer 2

when the tidal actions give rise to accretion of sands enclosed areas of the seashore either:
- directly in front of the existing shore or
- further out below the low tide line, often associated with the presence of a promontory (causing slowing of tidal currents)

Question 3

What does wind action cause?

Answer 3

it causes dry sand deposition around emergent colonising plants (that slow windspeed) called Foreshore colonisers

Question 4

Types of foreshore colonisers

Answer 4

• Cakile maritima (sea rocket)
• Atriplex spp (Orache)
• Salsola Kali (saltwort)

Question 5

When does the first dune ridge appear?

Answer 5

appears as more sand is trapped by foredune colonisers

Question 6

Types of foredune colonisers

Answer 6

• Elymus farctus (sand couch grass)
• Leymus arenarius (lyme grass)
• Ammophilia arenaria (marram grass)
• Honkenya peploides (sea sandwort)

Question 7

What happens at the front of the dune system?

Answer 7

further tidal deposition of sand at foreshore leads to the appearance of a new dune ridge called foredune

Question 8

What does the original dune become and what is it dominated by?

Answer 8

the original dune becomes a fixed dune ridge behind the foredune dominated by:
- Ammophilia arenaria (marram grass)
- Euphorbia paralis (sea spurge)
- Senecio jacobea (ragwort)
- Triplerospermum maritimum (mayweed)
- Taraxacum officinale (dandelion)

Question 9

What happens as dunes age?

Answer 9

as they age and new foredunes form, older dunes change in their structure and vegetation

Question 10

When dunes age to become the second fixed ridge, what species appear?

Answer 10

• Festura rubra (red fescue)
• Viola spp. (violets)
• Plantago martima (plantain)
• Lotus corniculatus (birdsfoot trefoil)
• Trifolium arvense (hare’s foot clover)
• Rhinathus minor (yellow rattle) hemiparasitic on other plants

Question 11

Succession on sand dunes : primary succession

Answer 11

• the original first dune ridges are gradually pushed further inland in the succession
• soil organic matter and organic nutrients begin to increase
• the slightly acid nature of rainfall causes soil to become less alkaline
• fungi and bacteria become more widespread

Question 12

What woody species appear in primary succession?

Answer 12

• Rosa spinosissima (Burnett’s rose)
• Salix repens (creeping willow)

Question 13

Mature dunes/dune slacks develop between the older dune ridges are characterised by? what plants are present?

Answer 13

they are characterised by damp neutral soil and the presence of
- Alnus glutinosa (alder)
- Salix repens (creeping willow)

Question 14

What is a mature dune system characterised by?

Answer 14

a range of different habitats of different ages
- generally lower fertility and water retention compared to terrestrial habitats
- occasional large mammals: hare, badger, fox, especially on coastal dunes rather than dune islands

Question 15

What are the two ways spatial variation arises?

Answer 15

1. succession: a dynamic process, giving rise to continuous localised change over time
2. zonation: a form of stasis, where localised differences are permanent

Question 16

Zonations occurs…

Answer 16

where two markedly different habitats converge e.g. the seashore
- at either extreme, characteristic species of each habitat predominate
- zonation between habitats tends to be stable

Question 17

The intermediate zone

Answer 17

• usually has very few of the characteristic species
• often contains several uniquely adapted species
• spatial location may change
• this zone rarely changes into a new habitat

Question 18

The intertidal zone

Answer 18

• aka the littoral zone is where land and sea meet, between high and low tides
• rich in nutrients and oxygen
• have hard (rocky shores) or soft (sandy, muddy shores) substrata and are influenced by factors like tidal range, slope and exposure

Question 19

When are seashore organisms exposed to air?

Answer 19

when the tide goes out
- due to tide coming in and going out 2x a day, organisms at the top of the shore are exposed to air more often than those at the bottom
- resulting in a vertical zonation

Question 20

What is the main reason for vertical zonation?

Answer 20

the varying ability of the organisms to withstand desiccation when the tide is out