Temperate Coastal Management Flashcards
What natural factors influence coastal zone dynamics?
- Wind
- Surf
- Precipitation
- Changes in World Ocean level
- Coastal vegetation
- Ice
- River run-off
What anthropogenic factors influence coastal zone dynamics?
Anthropogenic factors
- Hydro-engineering constructions (dams, port facilities)
- Civil and industrial engineering
- Dredging and aggregation
- Mining operations
- Destroying vegetation
- Coastal protection constructions
- Water intake and spillways
What are the two different types of management strategies?
Reactive (to something that happenned)
- Uncoordinated action
- Act on an event
Proactive (prevention–planned)
- Horizontal
- Same level, different sector
- Vertical integration
- Same sector, different level
What are features characteristic of saltr marshes?
- vSubjected to inundation by seawater - intertidal systems
- vDominated by angiosperms
- vLow wave energy environments
- vSurplus of fine sediment
- vReplaced by mangroves in the tropics
What are the main threats to salt marsh systems?
- Land reclamation (marine space reclaimed for other purposes) and habitat management.
- Erosion and coastal squeeze
- Invasive species
- Changes in sediment dynamics
- Agricultural use
- Pollution
How can the threat of land reclamation be reduced?
Includes industrial development, waste disposal sites, transport infrastructure etc
Reduce by:
- Allow to undergo natural processes of erosion, deposition and plant growth.
- Avoiding disturbance
- Maintaining a natural hydrological regime
- Retaining all successional stages
- Retaining biodegradable tidal debris
What is coastal squeeze?
Coastal squeeze is defined as intertidal habitat loss which arises due to the high water mark being fixed by a defence and the low water mark migrating landwards in response to sea level rise.
How is coastal squeeze reduced?
Reduce by:
- Considering a managed retreat
- Retaining flood embankments, behind the embankments upper marsh areas are created
- Preventing excessive scrub transition
What are sediment dynamics altered by?
- Land claim has an impact on general movement of sediment in sediment cells.
- Coastal defences built a series of hard coast defences.
- Dredging – industry, shipping, building in harbours – remove sediment form the system.
What is the effect of agricultral use on salt marsh systems?
Agricultural use –
Moderate levels of grazing can be beneficial to diversity.
Grazing should not be introduced at non-managed sites.
Cattle grazing – most uniform grazing.
WIDER READING: restoring salt marshes
Castillo, J.M. & Figueroa, E. (2009). Restoring salt marshes using small cordgrass, Spartina maritima. Restoration Ecology, 17: 324-326.
- The use of exotic cordgrasses in salt marsh restoration projects has caused important negative environmental impacts.
- Spartina maritima is the one of the only native cord-grass in many European estuarine environments and is becoming increasingly endangered.
- Our ecological restoration project had four specific goals: (1) to recover native vegetation, restoring the degraded landscape; (2) to phytostabilize oil-polluted sediments; (3) to prevent erosion and stabilize banks; and (4) to promote the conservation of S. maritima, an endan- gered species included on some European red lists (Eng- land—Cooper 1993; Cantabrian Coast of Spain—Bueno 1997; southwest coast of Spain—Cabezudo et al. 2005).
- Clumps of Spartina maritima have to be obtained from natural populations because this cordgrass is not cultivated at nurseries.
- Functions of the Spartina maritima plantings may change between successional and nonsuccessional marshes because it survives for decades at the later and it is outcompeted by other species at the former, facilitating succession development and increasing biodiversity.
- Ecological restoration of European salt marshes using the native cordgrass Spartina maritima as a biotool may have multiple benefits such as to restore degraded land- scapes, to phytostabilize polluted sediments, to prevent erosion, and to provide a base for habitat development.
The use of exotic cordgrasses in salt marsh restoration projects has caused important negative environmental impacts and little is known about the possibilities of applying the endangered cordgrass Spartina maritima as a biotool at many European estuaries where it is the only native cordgrass. This paper discusses the planning and the development of an innovative restoration project based on S. maritima plantations in Odiel marshes (S.W. Iberian Peninsula).
WIDER READING: saltmarsh erosion
* van der Wala, D. & Pye, C. (2004). Patterns, rates and possible causes of saltmarsh erosion in the Greater Thames area (UK). Geomorphology, 61: 373-391.
- Case study of the Deben estuary – UK
- Studies of saltmarsh change in the Deben covering the periods 1971 to 1998 reported a reduction in area from 311.7 hectares to 240.7 hectares, representing a net loss of 22.8 per cent loss (Cooper & Cooper, 2000).
- Sea levels on the south-east coast of England are increasing by between 1.5 and 2mm per year.
- Land use changes and enclosure of former intertidal areas have modified the hydrodynamic regime of the Deben estuary changing water and sediment circulation, influencing relative sea level, and preventing landward migration of saltmarsh in response to sea level rise. These factors are likely to have led to the large-scale erosion of saltmarsh which has shown considerable losses over the period that studies have been reporting on saltmarsh change.
- Reduced sediment supply, pollution, excavations within the saltmarsh, and possibly boat wash, may also be contributory factors.
What features are characteristic of sand dune systems?
- Supra-littoral – above high water line
- Aeolian and wave-driven transport
- Receive, store and release excess sand – sand dunes form
- Act as a buffer against wave action – dissipate wave energy
- Regulate coastal water table
- Global distribution
What are the different sucsessional dunes ?
- vFormation commences at strand line
- vForedunes – ephemeral and embryo
- vYellow dunes – dune-building species (marram and lime grass)
- vGrey dunes – 100% vegetation cover
- vDune slack – moisture level dependent on water table
- vMature dune – end point of succession
WIDER READING: coastak fordune zonation
- vDoing, H. (1985). Coastal foredune zonation and succession in various parts of the world. Vegetation, 61: 65-75.
- vo Proposal of 6 distinct fore-dune zones: 1-Ephemerous tidemark communities; 2-Perennial tidemark communities; 3-Embryonic dunes or frontal ridge; 4-Central fore-dune ridge; 5-Sheltered zone; 6-Pioneer communities in stabilized communities.
- vo The most complex areas in dunes are where the effects of disturbance by wind and fixation by plant growth are approximately equal.
