Plant Succession and Climax Vegetation

1. Plant Succession and Climax Vegetation Case Study Sand Dune Succession

2. Aims • You should be able to explain the term ecosystem and the processes which produce ecosystems. • You should be able to explain what is meant by climax vegetation. • Describe and explain the process known as plant succession with specific reference to a sand dune transect.

3. Ecosystems • A system in which plants, animals, insects and miro organisims (Biotic) interact with the natural environment which includes climate, rocks, and soil (Abiotic). • Small area of land in a garden. • Whole zones of rainforest.

4. An Oaktree EcoSystem • First there is the roots, soil and leaf-litter zone beneath the tree. Here decomposers such as bacteria, woodlice, and earthworms feed off last year's leaves and acorns, and fungi grow on its roots • Next is the trunk layer, which provides shelter or food to insects, caterpillars and larvae. • Finally comes the branches, leaves and canopy. In this zone bees gather pollen and nectar, fungi grow on the leaves, gall wasps and moths lay their eggs, and squirrels gather acorns. Small birds such as bluetits hunt the moth larvae; and sparrowhawks hunt the small birds

5. Flow of energy, the main source of which is the sun. Solar energy absorbed by plants. This energy passes through the ecosystem in food chains. Recycling of nutrients. Plants absorb nutrients from the soil and these are passed on to animals which die, decompose and return to the soil. An Ecosystem depends on two main processes.

6. Plant succession • The process of plant succession involves a series of stages during which the species of plant life changes. • From the pioneer stage to the…..climax vegetation. • Read page 162 an example of plant succession on a scree slope.

7. An example of plant succession • The first of these stages is referred to as the __________ stage. At this stage the first plants that __________ are completely new, perhaps a bare site such as a beach or sand dune are called__________. • The pioneer plants through their______ ______, begin to bind the soil together preventing its removal by wind or rain. Gradually the soil is ___________ and this assists in the process of plant succession. • The pioneer plants add __________ matter to the soil that holds water and nutrients. This is turn changes the conditions of the site sufficiently so as to allow other less _____________ plants to become established. • __________ and ____________which were present in the pioneer stage may be replaced by __________ which in turn may eventually give way to _________ and __________. This would be known as the _________ vegetation which is the final stage in the process and these plants would be in a state of ___________. Root action, Equilibrium, Pioneer, Grasses, Mosses, Lichens, Protected, Pioneers, Shrubs, Colonise, Woodland, Organic, Resilient, Climax.

8. The first of these stages is referred to as the pioneer stage. At this stage the first plants that colonise are completely new, perhaps a bare site such as a beach or sand dune are called pioneers. The pioneer plants through their root action, begin to bind the soil together preventing its removal by wind or rain. Gradually the soil is protected and this assists in the process of plant succession. The pioneer plants add organic matter to the soil that holds water and nutrients. This is turn changes the conditions of the site sufficiently so as to allow other less resilient plants to become established. Lichens and mosses which were present in the pioneer stage may be replaced by grasses which in turn may eventually give way to shrubs and woodland. This would be known as the climax vegetation which is the final stage in the process and these plants would be in a state of equilibrium.

9. Sand Dune Succession • Sand dune succession can be split into four zones reflecting the development of sand dunes, plant communities and their effect on each other. • The zones can be seen below; • Zone 1: Strandline to Fore Dunes (Pioneer stage) • Zone 2: Yellow Dunes (Building Stage) • Zone 3: Grey (Fixed) Dunes (Building Stage) • Zone 4: Dune Heath/Grass (Climax Stage)

10. Important trends in sand dune succession are; • Important trends in sand dune succession are; • Sea Shore Inland • ·       pH declines • ·       Salinity declines • ·       Age of dunes increases • ·       Available nutrients increase • ·       Available water increases • ·       Humus content increases • ·       Shelter increases

11. Sand Dune Transect

12. Zone 1: Strandline to Fore Dunes • Pioneer plants such as Saltwort, Sea Rocket, Sea Lyme. • Plants that can survive in very salty conditions. • For short periods of time they can survive under salt water. • Some have waxy frosting on surface to resist salt spray. • Fresh water from rain so roots go deep underground and close tosurface of sand looking for moist sand. Sea Rocket/Sea Couch Sea Lyme

13. Zone 2: Yellow Dunes • Building stage (early) plants such as Marram Grass. • Salt and alkalinity content starting to decrease ·        • Marram Grass starting to dominate, it cannot tolerate salt water so is more common in this zone (2) than zone (1). • In general though a slightly greater variety of species, ashumusstarting to develop, demise of pioneers such as Saltwort, aiding humification.

14. Plants may include sand sedge, mosses, lichens, sea holly. Yellow Dunes • Marram has very long roots so can tap into underground supplies and alsotolerant of drought conditions. • Plants are starting to stabilise dunes through their root systems. • Marram grass grows apace with dunes at about 1m/annum so taller dunes developing 5-10m high providing shelter. Youngish dunes, which are still developing. • Name derives from the rapid growth of the dunes from newly wind blown sand, which is yellow.

15. Sea Holly

16. Zone 3: Grey Fixed Dunes Plants in later part of building stages such as Clover & Chickweed. Some areas of slack water, where the water table reaches to or close to the surface resulting in water logging and plants such as reeds & rushes. Further reduction of alkalinity now about7.5pH and also salt reduced, both as a result of distance from sea shore. Now starting to see a deeper humus develop as more plant species colonizing and more neutral pH allows improved humification so morenutrients in soil. Closer to water table so easier access to fresher water, Humus gives the characteristic grey look to the dunes.

18. Mature Dune • The most mature dunes are found several hundred metres from the shore. Left undisturbed these dunes develop a soil which can support shrubs and trees including hawthorn, ash and birch. Humans may, as in the picture on the right, plant fast-growing conifers which flourish in the sandy soil. Eventually an oakclimax vegetation may develop.

19. Zone 4 Mature Dune More or less the climax stage with plants such as heaths, gorse and possibly some trees such as birch. T The widest variety of plants as the dunes are more stable and unlikely to move from wind action. Dunes several hundred metres from the shore. The deepest humus layer with the greatest nutrients and slightly acidic pH and lowest alkalinity. In the UK the true final stage of dune succession is rarely seen whereby mixed woodlands develop including trees such as Pine, Birch and Oak are common,

20. Transect Of Sand Dune Progression seaweed marram grass lyme grass, sea couch grass, marram, sea rocket saltwort ragworts creeping fescue, sand sedge, mosses, lichens, sea holly and sea spurge. Red fescue, sand sedge, sea spurge brambles, gorse, buckthorn rushes, sedges, cotton grass and creeping willow hawthorn, ash and birch pH  8, rapid drainage, high salt spray & high wind Dunes up to 5m high, mararm grass roots long bind sand pH  7.5, more shelter & less salt spray, 5 -10m dunes Vegetation 100% in places, shelter humus, 10m + dunes & wide, more acid soil water table reaches the surface, wet (waterlogged) & sheltered, peaty soil Several 100m’s from shore, soil for shrub trees, humus