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.