1. Saltmarshes

2. Saltmarshes
Saltmarshes often found in upper reaches of an estuary (and elsewhere)
Sand/Clay/Silt and/or organic materials
Minerogenic or organogenic marshes
Classification into: open coast marshes; back-barrier marshes; estuarine-fringing marshes; embayment marshes; loch or fjord-head marshes

3. Saltmarshes
Evidence of accretion (but also erosion)
Controlling Factors: sediment supply; tidal regime; wind-wave climate; movement of relative sea level
Tidal cycles, inundation, accretion
Saltmarsh ecosystems are sensitive to changes in sea level and isostatic adjustments to the level of the land

4. Saltmarshes
Tidal range and exposure
Submergence and emergence marsh
Low, middle and high marsh
Accreting salt marshes can gain height and prograde (increase in seaward extent)
Saltmarshes can build in height (vertical accretion) but can also suffer subsidence (compaction of sediments)

5. Saltmarshes
A salt marsh is "born" by the arrival of a seed or the rafting of a plant of the cord grass Spartina alterniflora. The grass spreads asexually by means of a subterranean rhizome system. The grass becomes dense and forms a baffle, which encourages the deposition of fine particulate sediment, including organic matter (salt marsh peat). This, in effect, causes a rise of the sediment surface and makes the habitat more terrestrial. As this happens, other somewhat less salt-tolerant grasses are able to invade. Eventually, this series of invasions and takeovers leads to a vertical zonation of grasses and a spread of the entire marsh system.
SAS = Spartina alterniflora - short form
SP = Spartina patens, the next higher grass species

6. Saltmarshes
Topography of saltmarsh results from the interaction of the processes of deposition, erosion, and sediment consolidation
Formation of Creeks and Salt Pans
Primary and Secondary Pans
Creek or Channel Pans
Microtopography

7. Saltmarshes
Slope and presence of creeks and salt pans influences the distribution of animals and plants
Zonation of vegetation (low, medium, high)
Number and distribution affected by location in saltmarsh, but also local climate e.g precipitation as well as evapotranspiration
Many species of plants and animals

8. Saltmarshes

9. Saltmarshes

10. Saltmarshes

11. Saltmarshes
Flora: Salicornia and Sarcocorni (glassworts), Spartina (cord-grass), Juncus (rushes), Plantago (plantains), and Limomium (sea-lavendars) - grasses are often very common ( Spartina anglica, Puccinellia maritima, Festuca rubra, Agrostis stolonifera, Phragmites australis, Spartina alterniflora

12. Saltmarshes
Developmental zonation
Many saltmarshes are very old - well established
Zonation may be well established
Vegetation succession (organisms and environment - Autogenic versus Allogenic factors)
Varying nutrient, fluvial and groundwater fluxes between saltmarshes and estuaries

13. Saltmarshes
Net importers / Net exporters of nutrients (nutrient flux)
In maritime saltmarshes: tides influence sedimentation rates, ionic relationships, water regime, photosynthesis, and ability of seedlings to establish

14. Saltmarshes
Animals:marine invertebrates, deposit feeders, burrowing worms, oligochaete and polychaete worms, crustaceans, ragworms, bivalve molluscs, gastropods, crabs, fish, insects, birds, rabbits

15. Saltmarshes
Facultative mutualisms between Spartina alterniflora and the marsh mussel Geukensia demissa and between and fiddler crabs Uca pugax
Fiddler crabs increase soil aeration
Mussels deposit nitrogenous wastes
Spartina anglica - invades intertidal flats rich in invertebrates and promotes reclamation
In some places losing ground - oil pollution and accumulation of fine-grained sediment

16. Saltmarshes
Saltmarsh dynamics
Seasonal growth and dieback
Halophytes and Glycophytes
Seasonal biomass accumulation
Rainfall and salinity affects vegetation cover/survival
Seasonal behaviour in animals e.g. birds
Impact of grazing on plants and succession
Biomass, productivity and energy flow
Algal productivity: creek sides, plant stems

17. Saltmarshes
Spartina alterniflora marsh
Ecological processes involved in terms of the overall carbon balance
Ecological processes in the water: phytoplankton, filter feeding, particle feeding, microbial assimilation
Ecological processes in the marsh sediments
Tidal exchange for transport of organic matter

18. Sand Dunes

19. Sand Dunes
Large supplies of sand moved onshore by wind
Integrated beach-dune system
Deflation / Abrasion / Saltation / Surface Creep
Sand dunes found around the World
Dynamic environment but can become fixed
Some are devoid of vegetation others are not (phytogenic)

20. Sand Dunes
Different classifications of dunes
Shape or form, orientation (parabolic, transverse, longitudinal)
Characterised by spatial distribution of sand, height, presence/absence of vegetation, topography
Formation (and duration) dependent upon supply of sand, obstacles, rate of sand transport, wind direction/speed, changes

21. Sand Dunes
Transect through dunes: sea, foreshore, strandline, backshore, embryo dunes, mobile (young or yellow dunes), (lower) unconsolidated dunes, consolidated (mature) grey dunes, and the maritime sward (dune heath) (also dune slacks)
From sea to land: ground wind speed, influence of salt spray, soil pH and levels of soil calcium, and sodium diminish whilst….

22. Sand Dunes
Extent of vegetation cover, amount of organic matter, number of plant and animal species and overall stability increase
Exposure and shelter (from wind and salt water) determine the type and distribution of plants
Landform, soil and water regime have an influence on the vegetation
Over time soils develop: mineral versus organic material e.g. in dune slacks

23. Sand Dunes
Mobility of sand through erosion will determine where the vegetation grows
Sand often has little in the way of nutrients
Limiting levels of nutrients: nitrogen, phosphorous and potassium
Shell fragments provide calcium
As the proportion of organic matter increases so the ability of the soil to retain moisture and nutrients rises
Fixed rather than mobile dunes will have more soil development

24. Sand Dunes
Soil processes active e.g. leaching will wash out nutrients in soils (lower in the profile or out of the ‘system’)
Vegetation once established will contribute e.g. organic carbon
Access to water via the water table
Also dew formation (water carried in air from sea) provides valuable moisture for shallow rooted plants in sand dunes

25. Sand Dunes
Dune slacks (wet and dry)
Presence of water dependent upon water table (also from dew and rainfall)
Provides water supply for plants
Also capillary water - accessed via deep rooting systems
Availabilty of water determines distribution of plants
Besides vascular plants also presence of non-vascular such as mosses and lichens

26. Sand Dunes
Vegetation in dune systems is affected by grazing e.g. by rabbits
Exposure of soil and sand to erosion
Affects species structure and diversity
Also effects of trampling
Large areas of dunes often covered in marram grass (rhizome fragments and also seedlings)
Sand traps

27. Sand Dunes
Vegetation: Ammophila arenaria P (marram), Elytrigia juncea P (sand couch-grass), Honckenya peploides P (sea sandwort), Cakile maritima A (sea rocket), Euphorbia paralias P (sea spurge), Salsola kali A (prickly saltwort) - annuals, biennials, perennials
Also lichens and mosses
Animal populations e.g. birds, reptiles (lizards (Lacerta agilis; Lacerta vivipara) and snakes (Coronella austriaca), and insects

28. Sand Dunes

29. Sand Dunes
Stabilizing role of marram grass
Dieback of marram can be due to poor aeration, mineral content deficiency, competition for nutrients, toxicity, natural senescence
Soil biota (mycorrhizal fungi and nematodes) play a major role in vigour of marram
Areas of deflation are ideal for the settlement of species such as meadow red fescue - source of water
In some dune systems shrubs e.g. Sands of Forvie and forest e.g. Culbin Sands

30. Sand Dunes

31. Sand Dunes www-biol.paisley.ac.uk/bioref/ Habitats/Dunes2.htm

32. Sand Dunes
Influence of size and also humans (management, disease)
Affects biodiversity
Machair – April 20th