Succession

1. COASTAL ECOSYSTEMS

2. What is an Ecosystem? An ecosystem is a community of plants and animals and the physical environment in which they live. What are the components of an Ecosystem? Non-Living Environment Living Environment There are two main Coastal Ecosystems: (i) Sand Dunes and (ii) Salt Marshes

3. SUN ROCK SOIL AIR WATER ANIMALS VEGETATION How do elements of an ecosystems interact & affect each other?

5. Initially conditions are very harsh – only certain species survive ( pioneer species ) Over time the physical environment becomes more favourable to plant growth (with changes in soil, water availability etc.) As this occurs vegetation becomes more diverse, taller and more woody in character with an increase in biomass Eventually the Climax Community is reached (that best suited to the conditions) – often a particular tree species that becomes dominant THE PROCESS OF SUCCESSION Important – the focus of succession is CHANGE OVER TIME Back

6. PLANT SUCCESSION - A SUMMARY PIONEER COMMUNITY The first plants to colonise an area – e.g. in a Salt Marsh Ecosystem – halophytes such as Salicornia are the first to colonise as they can tolerate the saline environment. CLIMATIC CLIMAX (Natural Vegetation) The vegetation that is best adapted to the environment it is in (in balance with the soils and climate of the area) SERAL STAGES (temporary conditions which develop over time) PLANT SUCCESSION PRISERE (the complete chain of events from pioneer to Climax Community)

7. SAND DUNE SUCCESSION - PSAMMOSERES

8. How do Sand Dunes Develop? Sand Dunes are an important deposition feature formed by the wind (aeolian processes). They develop where: (i) There is a strong on-shore wind (ii) There is a large supply of sand (iii) There is a large inter-tidal range so that large areas of sand regularly dry out

10. 4. Another dune forms on the seaward side of the original dune – this shelters the original dune – causing a change in the environmental conditions – other types of vegetation begin to colonise. 5 . A sequence of dunes form (oldest inland) and the environmental conditions continue to change due to the change in vegetation 6. The number and diversity of plant species on the dune increases – eventually the climax community is reached.

11. Embryo Dunes Foredunes Semi-fixed Dunes Grey Dunes Climatic Climax Vegetation Dune Slacks Dune Scrub Typical Sand Dune Cross Section – showing stages of succession