Ecological Succession Morfa Harlech
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Ecological Ecological Succession Succession The Psammosere The Psammosere Morfa harlech sand Morfa harlech sand Dune System Dune System http://www.youtube.com/wa tch?v=gXK58da91gQ
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Transcript of Ecological Succession Morfa Harlech
Ecological SuccessionEcological SuccessionThe PsammosereThe Psammosere
Morfa harlech sand Dune Morfa harlech sand Dune SystemSystem
http://www.youtube.com/watch?v=gXK58da91gQ
Morfa Harlech Dunes, North West Wales
Morfa Harlech was first notified as an SSSI in 1953 and has subsequently been revised (CCW ref. 31WNT). It is 1536ha in extent. It was designated as a combined biological and geomorphological site. An extensive area of estuary mudflats, saltmarshes, sand dunes and dune grassland, all of considerable biological value. Morfa Harlech is an important site for geomorphology studies. It comprises a major cuspate foreland in which the alignment of a sand beach and dunes at an acute angle to former cliffs has encouraged extensive sedimentation.
Ecological SuccessionEcological Succession Some more definitions….Some more definitions….
Abiotic factorsAbiotic factors – Non-living influences upon – Non-living influences upon the environment the environment e.g. climatic factors.e.g. climatic factors.
Biotic FactorsBiotic Factors – Influences upon the – Influences upon the environment arising from living organisms environment arising from living organisms e.g. burrowing rabbits.e.g. burrowing rabbits.
Ecological SuccessionEcological Succession Grime (1979) suggested 3 types of plant involved in succession.Grime (1979) suggested 3 types of plant involved in succession.
RuderalRuderal plants suited to: plants suited to: Frequent disturbance Frequent disturbance(Opportunist Species)(Opportunist Species) No competition No competition
CompetitiveCompetitive plants suited to: plants suited to: Low Disturbance Low Disturbance Low stressLow stress
Stress TolerantStress Tolerant plants suited to: Low Disturbance plants suited to: Low Disturbance High StressHigh Stress
Pioneer Communities
Climax Community
The Sand Dune EcosystemThe Sand Dune Ecosystem(Psammosere) (Psammosere)
Succession
Embryo DunesEmbryo Dunes Sand continually moves around the beach, it Sand continually moves around the beach, it
needs an obstruction such as driftwood to needs an obstruction such as driftwood to break the force of the wind and allow sand to break the force of the wind and allow sand to accumulate.accumulate.
Embryo dunes will begin to form.Embryo dunes will begin to form. They can grow to a height of 1m. They can grow to a height of 1m.
Marram grassMarram grassMarram grass is a xerophytic plant, meaning that it is a plant that is Marram grass is a xerophytic plant, meaning that it is a plant that is adapted to living in a dry arid habitat. Therefore it is most likely to be adapted to living in a dry arid habitat. Therefore it is most likely to be found on sand dunes, where the water is minimal and also where, found on sand dunes, where the water is minimal and also where, closer to the shore (if the sand dunes are by the sea), there is a higher closer to the shore (if the sand dunes are by the sea), there is a higher salt content, lowering the water potential. Marram grass has many salt content, lowering the water potential. Marram grass has many adaptations to living in the sand dunes, for example its leaf blades adaptations to living in the sand dunes, for example its leaf blades curve with the stomata on the inside, to reduce evaporation due to heat curve with the stomata on the inside, to reduce evaporation due to heat or wind (transpiration), also this provides a moist microclimate around or wind (transpiration), also this provides a moist microclimate around the stomata (ref. Biozone international). Marram grass blades also have the stomata (ref. Biozone international). Marram grass blades also have leaf hairs, which hold moist air around the leaf to prevent evaporation. leaf hairs, which hold moist air around the leaf to prevent evaporation. Marram grass has an extensive root system to gain as much water as Marram grass has an extensive root system to gain as much water as possible from the water deficient habitat. Furthermore Marram grass possible from the water deficient habitat. Furthermore Marram grass has a thick waxy cuticle, reducing water loss by evaporation and also, has a thick waxy cuticle, reducing water loss by evaporation and also, because it is shiny, reflects some of the heat.because it is shiny, reflects some of the heat.
Fore DunesFore Dunes The first colonising plants (or ruderal plants) The first colonising plants (or ruderal plants)
are lyme grass, sea couch and marram grass.are lyme grass, sea couch and marram grass. All are drought resistant and capable of All are drought resistant and capable of
withstanding burial by shifting sand.withstanding burial by shifting sand. These species will trap more sand.These species will trap more sand. pH Alkaline of around pH 8.5.pH Alkaline of around pH 8.5. The Fore Dunes will reach around 5m in The Fore Dunes will reach around 5m in
height.height.
Elytrigia atherica (Link) Kerguelen ex Carreras Mart. (Sea Couch)
Yellow DunesYellow Dunes Stable conditions allow a greater diversity of Stable conditions allow a greater diversity of
plant species.plant species. As plants die and decay a humus layer builds As plants die and decay a humus layer builds
up trapping water and nutrients.up trapping water and nutrients. Marram grass is still the dominant plant Marram grass is still the dominant plant
species.species. 80% of the dune is covered in now vegetated.80% of the dune is covered in now vegetated. Rabbits may be seenRabbits may be seen The Fore dunes can be 5 – 10m high.The Fore dunes can be 5 – 10m high.
Grey DunesGrey Dunes Even greater stability, 50 – 100m from the sea.Even greater stability, 50 – 100m from the sea. Vegetation cover may reach 100% as mosses Vegetation cover may reach 100% as mosses
and lichens fill any gaps in the vegetation.and lichens fill any gaps in the vegetation. Some small shrubs (brambles, gorse, Some small shrubs (brambles, gorse,
buckthorn – Competitor Species) appear for buckthorn – Competitor Species) appear for the first time due to sheltered conditions.the first time due to sheltered conditions.
Water content is low and plants need Water content is low and plants need spreading root systems.spreading root systems.
Dune height will be over 10m in height.Dune height will be over 10m in height.
Dune SlacksDune Slacks Dune slacks are found between more mature Dune slacks are found between more mature
dunesdunes The water table may reach the surface leading The water table may reach the surface leading
to permanent waterlogging and surface water.to permanent waterlogging and surface water. Specially adapted species such as rushes, Specially adapted species such as rushes,
sedge, cotton grass or creeping willow may sedge, cotton grass or creeping willow may appear.appear.
A peaty soil may develop.A peaty soil may develop.
Mature DunesMature Dunes The most mature dunes are found several The most mature dunes are found several
hundred meters from the shore.hundred meters from the shore. A soil will develop which can support shrubs A soil will develop which can support shrubs
and trees such as hawthorn, ash and birch.and trees such as hawthorn, ash and birch. Eventually a climax community of Oak (Stress Eventually a climax community of Oak (Stress
Tolerant) will develop.Tolerant) will develop. Plant species diversity will fall.Plant species diversity will fall. pH falls to around pH 4.pH falls to around pH 4.
Sand dunes at riskSand dunes at risk Sand dunes are fragile ecosystemsSand dunes are fragile ecosystems Humans traipsing across the dunes can create Humans traipsing across the dunes can create
small paths, reducing vegetation cover, leading small paths, reducing vegetation cover, leading to creation of gullies.to creation of gullies.
Rabbits can burrow into the dunesRabbits can burrow into the dunes Wind action on these gullies can lead to Wind action on these gullies can lead to
blowouts.blowouts. Up to 50% of the dune may be lost.Up to 50% of the dune may be lost.
Managing Sand DunesManaging Sand Dunes Dunes will eventually have to be protected by the Dunes will eventually have to be protected by the
local authority.local authority. Ecologically important areas maybe fenced off, so Ecologically important areas maybe fenced off, so
that damage is confined to specific areas.that damage is confined to specific areas. Beach access could be confined to fenced off Beach access could be confined to fenced off
pathways.pathways. Information boards could be used to educate tourists.Information boards could be used to educate tourists. Blowouts can be repaired by trapping loose material Blowouts can be repaired by trapping loose material
with barriers such as old christmas trees.with barriers such as old christmas trees. These barriers are unsightly but will eventually be These barriers are unsightly but will eventually be
covered up as vegetation re-establishes itself.covered up as vegetation re-establishes itself.
http://vimeo.com/21190608
A very useful video for you to watch. It has A very useful video for you to watch. It has questions and things for you to think about.questions and things for you to think about.
SummarySummary Abiotic vs biotic influencing factors.Abiotic vs biotic influencing factors. Ruderal, Competitive, Stress Tolerant species.Ruderal, Competitive, Stress Tolerant species. The sand dune ecosystem – case study Morfa The sand dune ecosystem – case study Morfa
Harlech, NE Wales.Harlech, NE Wales. Managing the sand dune ecosystem.Managing the sand dune ecosystem.
ResourcesResources http://www.georesources.co.uk/csdintro.htm http://jncc.defra.gov.uk/pdf/gcrdb/GCRsiteaccount1886.pdfhttp://jncc.defra.gov.uk/pdf/gcrdb/GCRsiteaccount1886.pdf http://www.coolgeography.co.uk/GCSE/AQA/Coastalhttp://www.coolgeography.co.uk/GCSE/AQA/Coastal
%20Zone/Habitats/Sand%20dunes.htm%20Zone/Habitats/Sand%20dunes.htm http://www.powershow.com/view/3c7169-MWJiO/http://www.powershow.com/view/3c7169-MWJiO/
Higher_Geography_Biosphere_Vegetation_Succession_Sand_Higher_Geography_Biosphere_Vegetation_Succession_Sand_Dunes_powerpoint_ppt_presentationDunes_powerpoint_ppt_presentation
http://www.markedbyteachers.com/gcse/science/an-http://www.markedbyteachers.com/gcse/science/an-investigation-of-the-effect-of-a-named-abiotic-factor-upon-investigation-of-the-effect-of-a-named-abiotic-factor-upon-marram-grass-distribution-in-a-sand-dune-system.htmlmarram-grass-distribution-in-a-sand-dune-system.html
