Coastal squeeze

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This article will provide a summary of the concept of coastal squeeze as it relates to land claim and relative sea level rise. It is partly based on a section in an article on Effects of global climate change on European marine biodiversity by Lieven Therry.

Coastal Squeeze

A significant threat for coastal organisms is loss of habitat. This may be due to direct loss through coastal land claim. This often involves building structures to protect the land and/or infrastructure from erosion and sea defences to prevent erosion and/or flooding. These and other techniques effectivley 'fix' the coastline. This is particlularly important where it effects habitats and ecosystems that would normally move landward in response to erosive forces. Where there is a rise in sea level relative to the land a coastal squeeze[1] takes place. This is exacerbated by global warming, which not only leads to higher sea levels, but also an increase of the storm frequency. Increased storminess results in coastal erosion including cliff erosion, retreat of beaches, loss of salt marsh and dune scarping with vegetation loss.

Effects on coastal organisms

Europe accommodates a significant number of shorebirds in winter. Shorebird numbers depend on intertidal areas, so sea-level rise could reduce the carrying capacity for these shorebirds.[2]

Average sea level rise is predicted to be up to 90 cm by the year 2100. The highly adaptable sandy-shore biota will not be at direct risk from it. Onshore migration is the natural ecosystem response to rising sea levels, but this is stopped by fixed sea defenses. Beaches are trapped in a ‘coastal squeeze’ between the impacts of urbanization on the terrestrial side and manifestations of climate change at sea. While unconstrained, beaches are resilient, changing shape and extent naturally in response to storms and variations in wave climate and currents. However, human modifications of the coastal zone severely limit this flexibility.[3]This implements a fundamental conflict between protecting socio-economic activity and sustaining the ecological functioning of the coastal zone in Europe under rising sea levels. It suggests a need for more soft protection (nourishment), managed retreat, and possibly accommodation strategies. [2] [4]

Even ‘soft’ engineering solutions are not free of negative ecological consequences. The ecological consequences of engineering activities on beaches include the loss of biodiversity, productivity, and critical habitats as well as modifications of the subtidal zone which is an important recruitment zone for many sandy beach animals.[5] [6] [7] [8]

Coastal squeeze SOURCE: www3.hants.gov.uk

References

  1. Doody, J.P. (2004) 'Coastal squeeze' - an historical perspective. Journal of Coastal Conservation, 10/1-2, 129-138.
  2. 2,0 2,1 Nicholls, R.J.; Klein, R.J.T. (2005). Climate change and coastal management in Europe's coast, in: Vermaat, J.E. et al. (Ed.) (2005). Manging European coasts: past, present and future. pp. 199-226.
  3. Nordstrom, K.F. (2000). Beaches and dunes on developed coasts. Cambrige University Press, Cambridge, UK, cit. in: Schlacher, T.A.; Dugan, J.; Schoeman, D.S.; Lastra, M.; Jones, A.; Scapini, F.; McLachlan, A.; Defeo, O. (2007). Sandy beaches at the brink. Diversity and Distribution.
  4. McLachlan, A.; Brown, A.C. (2006). The ecology of sandy shores. 2nd. Edition. Academic Press: Amsterdam, The Netherlands. 373 pp.
  5. Dugan, J.E. & Hubbard, D.M. (2006). Ecological responses to coastal armouring on exposed sandy beaches. Shore and Beach 74: 10-16. cit. in: Schlacher, T.A.; Dugan, J.; Schoeman, D.S.; Lastra, M.; Jones, A.; Scapini, F.; McLachlan, A.; Defeo, O. (2007). Sandy beaches at the brink. Diversity and Distribution.
  6. Peterson, C.H. & Bishop, M.J. (2005). Assessing the environmental impacts of beach nourishment. Bioscience 55: 887-896. cit. in: Schlacher, T.A.; Dugan, J.; Schoeman, D.S.; Lastra, M.; Jones, A.; Scapini, F.; McLachlan, A.; Defeo, O. (2007). Sandy beaches at the brink. Diversity and Distribution.
  7. Peterson, C.H.; Bishop, M.J., Johnson, G.A.; D’Anna, L.M. & Manning, L.M. (2006). Exploiting beach filling as an unaffordable experiment: benthic intertidal impacts propagating upwards to shorebirds. Journal of Experimental Marine Biology and Ecology 338: 205-221. cit. in: Schlacher, T.A.; Dugan, J.; Schoeman, D.S.; Lastra, M.; Jones, A.; Scapini, F.; McLachlan, A.; Defeo, O. (2007). Sandy beaches at the brink. Diversity and Distribution.
  8. Speybroeck, J.; Bonte, D.; Courtens, W.; Gheskiere, T.; Grootaert, P.; Maelfait, J.P.; Mathys, M.; Provoost, S.; Sabbe, K.; Stienen, E.W.M.; Van Lancker, V.; Vincx, M. & Degraer, S. (2006). Beach nourishment: an ecologically sound coastal defence alternative? A revieuw. Aquatic conservation – Marine and Freshwater Ecosystems 16: 419-435. cit. in: Schlacher, T.A.; Dugan, J.; Schoeman, D.S.; Lastra, M.; Jones, A.; Scapini, F.; McLachlan, A.; Defeo, O. (2007). Sandy beaches at the brink. Diversity and Distribution.


The main author of this article is Doody, Pat
Please note that others may also have edited the contents of this article.