Succession Psammosere

Definitions Succession- directional change in vegetation in an area over time Psammosere- a seral community, an ecological succession that began life on newly exposed coastal sand. Most common is the sand dune systems Plagioclimax- an area or habitat in which the influences of the humans have prevented the ecosystem from developing further. E.g. Heather moorland Seral stage- a point within a plant succession characterised by a dominant species Climatic climax- final stage of succession where the vegetation is in equilibrium with the environmental conditions Pioneer species- first group of species to colonise and have specific adaption e.g. halophytes

Succession Primary succession (priseres)- growth on previously un- colonised land Xeroseres (dry land) Lithoseres (bare rock) Psammoseres (sand dune) Hydroseres (water) Haloseres (salt water) Hydroseres (fresh water) Secondary succession (subseres)- growth on previously colonised land due to destruction or modification of an existing plant community Natural e.g. landslide/fire Human Activity e.g. deforestation

Open system Inputs: wind, precipitation, sunlight for photosynthesis, weathered rock Outputs: evapotranspiration, through-flow, groundwater flow, leaching, runoff Flows: decomposition of litter to form humus, wake uptake my capillary action, biomass decreases when organisms die Stores: vegetation, plant litter, soils

General High water mark- point at which succession begins Pioneer community form a ground layer – xerophytes and halophytes Onshore wind (15km/h) blow sand around the base of the pioneer plant Plants bind the sand and help stabilise it Pioneer plants decompose and forms humus Organic matter is colonised by new species and the process continues The humus is very alkaline from shell fragments and salt and becomes increasingly acidic from addition of biomass

Development of a psammosere Strandline Sea Rocket Embryo dune Couch Grass Foredune Marram grass Yellow Dune Sedge grass Fixed dune Red fescue Scrub Bramble Woodland Oak Development of a psammosere Dune Heath (Heather) and Dune Slacks (creeping Willow)

Sea Rocket Strandline Line at the high water mark on the beach Long tap root to help stabilise the sand Thick waxy cuticle to help retain moisture Grow low to the ground so less affected by abrasive sand When buried by sand it responds by rapid growth and seed production Line at the high water mark on the beach Wind and sand prevent permanent communities Distance from sea (m) 0-20 pH 8.5 Humus (%) <1 Colour Yellow

Couch Grass Embryo Dunes An object such as a plant or rock causes sand to build on the lee side Small dunes build up Couch Grass Fine leaves to reduce water loss by evapotranspiration Adapted to well drained soils Spreads by rhizomes Distance from sea (m) 20-80 pH 8.0 Humus (%) <1 Colour Yellow

Fore Dunes and Yellow Dunes Marram Grass Humus results from decomposition of marram grass Species diversity begins Rolled leaves to trap a layer of air to maintain moisture Thick waxy cuticle Hairs on the leaves also trap a moisture layer Stomata on the lower surface to reduce water loss by transpiration Underground stems (rhizomes) tolerate high wind and it’s flexible Distance from sea (m) 80-300 pH 7.5- 7.0 Humus (%) <2.5 Colour Yellow

Fixed dunes Mosses cover the bare ground between marram grass colonies Fixed indicates no bare ground Humus creates a brown surface layer of up to 10cm deep allowing moisture to be maintained Legumes may contain nitrogogen fixing bacteria in their root nodules which allow for increased species diversity Distance from sea (m) 300-500 pH 6.5 Humus (%) 5 Colour Yellow/Grey

Dune Slack Overgrazing leaves bare substrate susceptible to erosion and forms depressions called blow- outs Forms a dune slack if it reaches the water table Distance from sea (m) 500-700 pH 6.5 Humus (%) 10 Colour Grey Slacks vary according to season and water table level: Dry slack – sea holly Wet slack- creeping willow

Bramble Dune scrub Small tress and shrubs colonise Community becomes species poor Distance from sea (m) 500 pH 6.0 Humus (%) 20 Colour Grey

Climax vegetation- Woodland \az ,mjH@k:b ] Risk from human activity Ecosystem- dynamic equilibrium Deep tap roots in search of water Broad leafed trees to maximise absorption of sunlight for photosynthesis Lose leaves in winter to conserve water Distance from sea (m) 2500 + pH 4.5 Humus (%) >40 Colour Brown Oak Tree

From sea to woodland Increase in height of dune from addition of humus and trapping of sediment around taller plants pH becomes increasingly more acidic as organic matter is added and less salt or shell (alkaline) Dune colour begins yellow and becomes grey/brown due to addition of organic matter Species increase in biomass and less adapted to saline conditions Affect of wind decreases due to protection Less leaching as soil becomes increasingly capable of retaining moisture

Threats to sand dunes Solutions: Cordoning off sensitive areas Human threats - Golf/ sport - Trampling Recreation: Development - Industry -Housing -forestry - Farmland Agriculture - Sewage - Nitrates Pollution Interference Groynes - Extraction Threats to sand dunes Solutions: Cordoning off sensitive areas Nature reserves - education Boardwalks Planting successful species to stabilise dunes

Studland Studland Bay forms the eastern seaward side of the South Haven Peninsula Onshore easterly winds, especially during storms can blow the sand inland. The source of the sand is the sand bottom of Poole Bay Studland's 5km of sandy beach is a popular tourist destination with all 6 of Britains reptiles, Little Sea, and a heathlands environment Can experience 25,000 people on its beaches per day in summer

Studland’s sustainable management Owned and managed by the National Trust since 1982 – no large scale developments Signed footpaths and boardwalks to reduce trampling Visitor centre to educate the need for conservation Blowouts fences off and stabilised by marram grass Provision of car parks- no driving onto the beach Fire beaters Honeypot site with café, toilets, bins to concentrate tourists Dog/ recycling binds Extensive ridged dune system