Learning Objectives Understand ecological successions Success Criteria

Learning ObjectivesUnderstand ecological successions

Success Criteria Describe and explain the meaning and the succession of a PSAMMOSERE

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Plant successionPlant succession is the development of plants. This can take place in many areas such asFresh water (hydosere)Bare rock (lithosere)Sand dunes (psammoseres)

Ecological successionDuring succession the ecosystem goes through a series of stages. Each stage is called a seral stage and the complete series of plant communities resulting from the process of succession is called a SERE!

PsammosereA psammosere is a plant succession on a sand dune. It consists of a series of dry sandy ridges interspaced with wet hollows called slacks.Sand dunes become stable when plant life develops

Three main stages

Pioneer stageSeeds are blown in by the wind or washed in by the sea. Rooting conditions are poor due to drought, strong winds and salty sea waster immersion and alkali conditions created by seashells

Three main stages

Building stagePlants trap sand and grown with in binding together the sand with their roots. The humus created by decaying pioneer plants creates more fertile conditions.

Three main stages

Climax stageTaller plants (like trees) and more complex species can now grow, Plants from earlier stages die out due to competition for light and water.

Climax Vegetation

Final stage of plant successionRelatively stable and self sustainingDoes not changeHigh highest biomass/ variety of speciesVegetation in harmony/ equilibrium with environmentScottish examples Oak, Pine, Birch woodlands

QuestionsWhat is a pioneer community?Why are these plants able to grow on bare rock?How does a thin layer of soil form on bare rock?What happens when smaller plants die?What is the name given to this event?What is climax vegetation?What does equilibrium mean?


Success CriteriaDescribe and explain the formation of a dune system

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Growing a Sand Dune system

A plentiful supply of sandStrong winds to transport sand particles through saltation (bouncing and hopping of sand on surface)An obstacle to trap the sand, usually its a plant or a piece of seaweed thats located on the tide or strand line

An aerial view of a sand dune systemyoungest dunesoldest dunes

A transect across a sand dune system...XYReveals variations in relief and vegetation ..

XYA transect across a sand dune system

Embryo and Fore Dunes: the environmenton-shore windshigh water markseaweed deposits humussand builds up against pioneer plantstransient dunespoor water retention

Embryo and Fore Dunes: the plantsThe plants which grow here have adaptations which allow them to grow in a difficult environment :

deep tap roots to obtain available moisture

Yellow Dunes: the environmentabove the level of high tides reduced wind speedsSurface continually blown away and replenished with fresh sandSoil slightly less alkaline and more water retentiveSome humus forming

Yellow Dunes: the plantsSalt tolerantThrives on being buried by sandInrolled leaves to reduce moisture lossLong tap rootsUnderground rhizomes stabilise the sand

Other plants such as Ragwort, Red fescue and Sand sedge begin to appearThe dominant plant species is Marram grass:

Grey Dunes: the environmentsheltered by higher, seaward duneslower pHhigher humus contentlittle mobile sandsand no longer accumulatinga more closed vegetation community in which marram grass is no longer able to compete

Grey Dunes: the plants

mainly perennialshigher species diversity

Dune Slacks: the environmentrelief intersects the water tablewater table high especially in wintersoil acidicoccur in low lying hollows between dune ridges

Dune Slacks: the plantsThe community which develops here comprises moisture-loving plants commonly found in many fresh water wetland areas e.g.Phragmites reedsFlag irisrushesBog cotton

Dune Heath/Woodland: the environmentwell sheltered from windsacidic soilnutrient richsoil has high organic matter content

Dune Heath / Woodland: the plantsHuman interference means that true mixed woodland climax vegetation is rarely seen on dune systems in the UK Most dune systems develop into a community of heathland, woody perennials (often spinous) and scattered treesHeatherSea buckthornHeather

Past paper handout 2008


Success Criteria Describe how plants have adapted in dune systems

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Vocab

Xerophytic plants which are water resistant

Hydrophytic plants which are water tolerant

Halophitic Salt resistant

Rhizomes long roots/ stems

Factors influencing dune stability

People

Soil

Climate

Slope

Other vegetation

People:People walk on dunes and trample plantsSoil:It is tidal so is never 100 % dry or 100% wetLack of organic content so less nutrientsAlkaline soils sea shellsSaline soils salty waterDrainage is too good can be a lack of waterClimate:Windy blows sad at plantsExposed no shade or shelterSlope:Sand is mobileSome plants may get buriedOther vegetation:CompetitionNot enough humus to support/ create different vegetation types

Marram Grass

Xerophytic (drought resistant)Long and sharp to prevent animals eating it Long rhizomes (underground stems) stabilise the dune/ bind sand togetherRhizomes also reach underground for water to deep water tableCurled up shape of grass reduces evapotranspirationGrows on bare soils with little competitionFast growing 1m per year

Yellow Dunes: the plantsSalt tolerantThrives on being buried by sandInrolled leaves to reduce moisture lossLong tap rootsUnderground rhizomes stabilise the sand

Other plants such as Ragwort, Red fescue and Sand sedge begin to appearThe dominant plant species is Marram grass:


Success CriteriaIdentify plant species along a psammosere transectDescribe how plants have adapted along a psammosere transect

True or FalseHumus content decreases as you go inlandPh declines as you move inlandPlants are well sheltered on the Embryo dunesMarran grass is found on the Yellow dunesDandelions are found on the Fore dunesSandwort can be found on the Embryo dunesSalt content increases inlandYellow dunes, Grey dunes and Mature dunes are all fixed dunesAt the climax stage plants are stable and relatively unchanging

Zone 1: Embryo and Fore dunesSand is poor in nutrients and is very dryThey are resistant to occasional immersion in water and are able to withstand high winds. Plants that grow here have lateral roots and underground stemsLow lying to avoid strong windsHigh salt toleranceWaxy leaves to retain moisture and withstand windsAlkaline with no humus

Embryo and Fore Dunes: the plants

Zone 2: Yellow DunesMarram grass becomes the dominant plantIts RHYZOMES (long creeping underground stems) help to bind deposited sand and reach water tableLeaves curl up in order to retain moisture Marram can align itself with prevailing wind toreduce moisture lossMarram grows quickly (~1 metre/ year) to keep above the sand.Salt tolerant

Yellow Dunes: the plantsRagwortMarran Grass

Zone 3: Gey Dunes and SlacksIncreased shelter + damper soil = higher species diversityShelter restricts supply of sandIncreased humus content Vegetation cover now complete Marram becomes more sparse

On Slacks, water table is near surface encouraging plants which prefer damp conditions

Grey Dunes: the plants

mainly perennialshigher species diversity

Dune Slacks: the plantsThe community which develops here comprises moisture-loving plants commonly found in many fresh water wetland areas e.g.ReedsFlag irisrushesBog cotton

Zone 4: woodland/ grasslandTaller species indicate a deeper and wetter soil.

Dune Heath / Woodland: the plantsHuman interference means that true mixed woodland climax vegetation is rarely seen on dune systems in the UK HeatherScots PineHeather


Success CriteriaExplain fully what is meant by climax vegetationExplain the plant succession in a sand dune

Explain what is meant by the term Climax vegetation?.

What is the question asking you to do?StructureWhat is importantKey wordsPlant types

4 marks

Explain what is meant by the term Climax vegetation?. Final stage/ stage of maturity = ecosystem is relatively unchanging and biomass is at a maximumDynamic equilibrium -maintains overall stability despite continuous small changes. Progression pioneers are displaced as conditions changePlants compete for water, nutrients and spaceSpecies such as scots pine and oak become dominant

4 marks

In your teams

With the aid of a diagram describe AND explain the plant succession in a sand dune habitat.You may wish to think aboutSuccessionPlant typeConditionsAdaptations

You have 20 minutes

Using the Core Higher Textbook....

Read pages 152-155Answer the following questions on page 173-1742(b)2(d)2(g)

Describe and Explain the changes in vegetation as you move inland from the coast.

What is the question asking you to do????

Give the name of a type of vegetation in the pioneer stage and say how it has adapted to that environment and do the same for each stage.

What do you need to mention Each stage from strandline to WoodlandConditionsHumus contentSalt contentPhShelterPlant typeAdaptations

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Learning Objectives Understand ecological successions Success Criteria