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The Introduction of coastal infrastructure as a driver of change
in marine environments
Elvis Torres Delgado
September 11, 2013
Some Concepts
• Intertidial zone – part of the shore that is above water at low tide and below the water at high tide.
• Nearshore – area that extends seawards from the low water line.
http://upload.wikimedia.org/wikipedia/commons/6/67/World_population_density_1994.png
Urban Growth
• High percentage of the population lives in the coast and they receive a lot of tourism.
• Urbanization and coastal structures affect the ecosystem.
• A lot of hard structures are added to “protect” the shores of erosion.
Cancun, Mexico
http://viajesalcaribe.eu/wp-content/uploads/2013/08/Imagebysafa2.jpg
Isla Verde, Puerto Rico
http://puertorico.com.pr/wp-content/uploads/2013/05/Isla-Verde-Beach-01.jpg
Ecological consequences of the introduction of artificial structure
• Artificial structures affect the normal epibiotaand fish assemblages. It’s worse with unnatural materials.
• Sometimes the problem is not the material, but the structural change what affects biota development (ex. lack of rock pools).
Ecological consequences of the introduction of artificial structure
• Unnatural structures may provide ideal conditions for the establishments of exotic species.
• Can also affect the species richness or abundance.
SeawallsBreakwaters
Jetties
http://marineinsight.com/wp-content/uploads/2010/12/SeaWall_Japan.jpg
http://www.fhwa.dot.gov/engineering/hydraulics/images/h25_712.jpg
http://www.choctawtrans.com/ag7217c050016/Breakwaters%20constructed.JPG
Ecological consequences of the introduction of artificial structure
• It is believed that some of these structures may resemble better the natural ones after many years of weathering.
• It has been shown that many of these artificial structures don’t support natural assembly even after many decades of exposition.
Effects on adjacent habitats
• Differences in diversity of species has been found in rocky shores bordered by seawalls.
• Biota living in artificial structures may be a food source for species nearby.
• Some structures favor a shift from consumers domination to producers domination.
Regional or large-scale changes
• Urbanization contributes to species homogenization.
• Artificial structures can help connect separated populations. Reduces gene flow and genetic diversity.
http://oceanexplorer.noaa.gov/explorations/03mex/logs/sept21/media/dscn0011_600.jpg
http://static.progressivemediagroup.com/uploads/imagelibrary/Rigs_Reefs_Six.jpg
Alternative management options
• New solutions to fight coastal erosion without using hard structures are being considered.
• In high wave energy a combination of natural and artificial elements may be needed (hybrid designs).
• Hard structures that consider suitable habitat for species affected by urbanization processes, fishing, recreation, and education are starting to get used.
Intertidal seawalls
http://cristinabump.files.wordpress.com/2011/01/sydney_mcmahons_point_seawall.jpg
http://sydney.edu.au/science/bio/eicc/images/content/p_seawalls_estuaries2.jpg
Final thoughts
• More interdisciplinary research is needed to understand the effects of urbanism on coastal ecosystem.
• There is a need to explore new solutions to protect coastal structures affecting the ecosystem as less as possible.