ECEC - 5

Question 1

what are the 3 main types of permanent wetland?

Answer 1

1) swamp
2) bog
3) fen

Question 2

Telematic wetlands is broken down into permanent and seasonal wetland, what is a seasonal wetland and what is a telematic wetland?

Answer 2

• marsh

- telematic wetlands = Wet terrestrial ecosystems

Question 3

what is the difference between swamp, bog and fen wetlands?

Answer 3

swamp = inundated (flooded) for most of the year

bog and fen = not inundated or for only part of the year

Question 4

what type of ecosystem is a marsh?

Answer 4

a transition between an aquatic and terrestrial ecosystem

Question 5

what is the definition of vegetation succession?

Answer 5

• A gradual, directional change in the composition of vegetation
• Populations of different plant species successively replace one another
• Usually accompanied by environmental change (either causing or resulting from succession)

Question 6

what does allogenic mean?

Answer 6

(other made) = succession driven by environmental change

Question 7

what does autogenic mean?

Answer 7

(self-made) = succession occurs when the vegetation itself induces environmental change, creates conditions conducive to its own replacement

Question 8

what is primary succession?

Answer 8

surfaces not previously supported by vegetation

Question 9

what is secondary succession?

Answer 9

surfaces that have previously supported soil and vegetation

Question 10

what are the 2 main processes peat accumulate through?

Answer 10

1) Terrestrialisation – infilling of lakes and pools with mud and peat – has occurred widely
2) Paludification – the process by which once dry land gets wetter - Increased wetness may be induced by various influences (e.g impeded drainage caused by sea-level rise, increased precipitation)
- Responsible for the development of the largest areas of wetland in Britain

Question 11

what are the 2 broad types of terrestrialisation?

Answer 11

1) Rooting (normal) terrestrialisation – water gradually shallows by the accumulation of mud and peat – allows progressive colonisation by species more suited to shallow-water conditions
2) Rafting terrestrialisation – open water becomes overgrown directly by a buoyant mat of peat – reduces the dependency of the succession on shallowing caused by the accumulation of mud and peat

Question 12

for rooting terrestrialisation what are 2 ways the mud/sediment is deposited?

Answer 12

Autochthonous – organic muds deposited in the original place
Allochthonous – in washed sediments

Question 13

what happens if rooting terrestrialisation occurs in a swamp?

Answer 13

shallowing permits establishment of immersive perennials

Question 14

what happens if rooting terrestrialisation occurs in a fen?

Answer 14

surface ceases to be inundated

Question 15

what is a fen woodland?

Answer 15

a fen surface which becomes increasingly dry and stable

Question 16

what is raised bog?

Answer 16

• Acidic ombrotrophic peat accumulates above the level of the fen water table
• The bog mass Sphagnum is a key peat-forming species in bogs

Question 17

describe rafting terrestrialisation

Answer 17

• Found in small sheltered basins
• Similar to rooting
• Swamp and fen phases develop by direct colonisation of open water
• Water body fills up top – downwards

Question 18

what was it initially thought caused development of blanket bog, what is it and now what is known to cause it?

Answer 18

• ombrogenous formation (peat) which ‘blankets’ terrain
• Initiation of blanket bog initially considered driven primarily by suitable climatic conditions (wet and cool).
• However, blanket bog can be found with Neolithic artefacts.
• Some has developed over once cultivated land (e.g. Dartmoor)
• now considered much is initiated by forest clearance

Question 19

what areas of Britain was blanket bog considered to be restricted to?

Answer 19

– restricted to oceanic regions with wet and cool climates (e.g. much of
western and northern Britain)
- however it was seen some once developed over cultivated land

Question 20

what are features of water logged environments?

Answer 20

• oxygen deficient (hypoxic - reduction and anoxic - completely gone)
• 02 diffusion 20,000 times slower in water than air
• 02 has low solubility in water
• affects availability of 02, NO3, Mn, Fe, S
• anoxic environment + souce of potential toxins + acidic conditions = retard normal process of decomposition

Question 21

what is one of the main reasons why peat accumulates?

Answer 21

retarded decomposition in water logged environments

Question 22

what are the 3 main adaptations of plants with lack of oxygen in the rooting zone?

Answer 22

1) anaerobic respiration in roots
2) transport of oxygen to roots
3) release of oxygen into the rhizosphere (soil around roots)

Question 23

describe the process of anaerobic respiration in the roots?

Answer 23

they accumulate the less toxic malic acid rather than ethanol however its not a long term adaption to waterlogging

Question 24

describe the process of transport of oxygen to the roots?

Answer 24

– high tissue porosity provided by aerenchyma, cavities and channels, other special oxygenating structures (pneumatophores; stilt roots)

Question 25

what are ppneumatophores?

Answer 25

upward growing roots e.g. mangroves take air directly into rooting systems
- roots have lenticels( raised pores) which also provide support for the plant

Question 26

how does the process of releasing oxygen into the rhizosphere work?

Answer 26

• diffusion of oxygen out of the root, enzymic oxidation on the root surface creating a small zone of aerobic conditions immediately around root
  – can also oxidise phytotoxins reducing toxicity and uptake by the plant
• dead stems of reed in winter may function as snorkels
  oxygenation can facilitate growth of other dryland species by oxidising surrounding soil

Question 27

what are the 2 waterlogging problems for plants?

Answer 27

1) Oxygen deficiency for underground organs
2) Increased availability of soluble phytotoxins
in soil – especially Mn, Fe and S-

Question 28

what other effects can plants with high rates of radial oxygen loss have?

Answer 28

• can sometimes oxidise the soil sufficiently well to permit the growth of others
• May facilitate growth of more ‘dryland’ species which could otherwise not grow in wet conditions
• An example of “facilitation”
• High rates of water movement (effectively oxygenating) can also facilitate the growth of some dryland species in wetlands