DOES SEA LEVEL RISE ENHANCE FISH HABITAT IN SALT MARSHES?

Impacts of Sea Level Rise on Fishes

Insightful

GeoInformatics

www.insightfulgeo.

ca

Source: IPCC, 2013

Sea level is expected to rise past historical levels in the next 100

years.

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Recent study show that sea level rise can drown and shrink

wetlands because of coastal squeeze.

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Projected distribution of salt marsh areas at Year 2100 sea levels (m)

Source: Torio & Chmura, 2013

How will a shrinking marsh surface affect fish habitats within the

salt marsh?

Image source: http://ian.umces.edu/imagelibrary/displayimage-4192.html

To examine the impacts sea level rise on salt marsh as fish habitats,

the size, configuration and connectivity of salt marsh patches were

evaluated.

Patch size and configuration Connectivity

Results indicate that at moderate sea level rise, salt marsh area

increased resulting in more available fish habitats.

-At high sea level, 40% of the future marshes will be in

private properties!

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Constant Accretion

Accretion = SLR

Carrying Capacity (ESLI)

Not only the size but also the variability of marsh patches increased

with moderate sea level rise.

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Sea Level (m)

Constant Accretion

Accretion = SLR

Patch size standard deviation Mean Patch Size

Apart from habitat size and variability, complexity of marsh edges

which provide refuge for small fishes also increased.

Edge Density Fractal Dimension

Furthermore, moderate flooding from sea level rise increased

connectivity between habitat patches.

Summary and conclusion

Moderate sea level rise resulted in

expansion of fish habitats. Moderate means

sea levels not exceeding 1 meter. Sea

levels exceeding this threshold resulted in

reduced habitat size, configuration and

fragmentation.