1. Vegetation Succession Sand Dunes

2. Plant Succession Evolution of plant communities From pioneer species to climax vegetation Related to change in the environment Change brought about by the plants themselves This change then favours new species ‘Plants are the architects of their own demise’

3. Sand Dune Transect

4. The Foreshore the strand line Blowing sand Salty Dry

5. Saltwort Fleshy leaves store water Deep tap roots Low growing

6. Sandwort Waxy leaves

7. Sea Rocket Fleshy, waxy leaves Tap roots

8. Frosted orache ‘ Mealy’ leaves are salt repellant Long tap roots

9. Couch grass Embryo Dune Leaves prostrate Withstands modest burial Tolerates salt

10. Saltwort Frosted orache Couch Grass

11. Embryo Dunes Scattered foreshore plants Seaweed (humus) On shore winds Sand builds up Highest tide line

12. Level of built-up sand

13. Frosted orache Embryo dune Lyme Grass

14. Embryo Dune Sand Couch and Lyme Grass Grow side roots laterally Underground Stems – rhizomes…this stabilizses the sand. Can tolerate occasional immersion in water. Sea rocket also found here.

15. Foredunes Couch grass (salt tolerant) Lyme grass (salt tolerant) Marram grass

16. Fore Dune Higher humus content Lower salt content. Marram grass becomes a key plant in stablizing the dunes.

17. Mobile (yellow) dunes Marram grass

18. Cannot tolerate salt ‘Thrives’ on being buried by sand Inrolled leaves Long tap roots Underground rhizomes stabilise dunes Deep roots anchor the grass in the sand. Can align with wind direction to reduce moisture loss

19. Much bare sand hence ‘yellow’

20. Yellow dune Marram grass, ragwort. Humus and soil acidity increased. Marram grass suited to the conditions Dry conditions.

21. Ragwort Marram

22. Less bare sand More humus Lower pH Less Marram More ‘competitors’

23. Fixed (grey) dunes Marram more sparse and weaker Other species dominate

24. Increasing floristic diversity Harebells Bedstraw Restharrow

25. Parasol mushrooms More humus and soil moisture

26. Why ‘grey’? Lichens

27. Marram now very sparse Ground cover almost complete

28. Dune slacks Main dune ridge Lower relief intersects water table

29. Phragmites reeds

30. Rushes

31. Seasonal slack Rushes Creeping willow

32. Main dune ridge Slack Dune heath Cotton grass

33. Final stages of succession Alkaline shell sand GrasslandHeathland Acid mineral sand

34. Dune Scrub (often spinous!) Gorse Buckthorn Dog rose

35. Mixed Woodland Climax Man’s activities usually prevents this from developing

36. New embryo dunes are forming…. Back on the foreshore…..