Hurricanes could lead to more hybrids


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Stronger hurricanes could lead to more reef fish hybridising, according to a study to be published in a forthcoming issue of the Journal of Experimental Marine Biology and Ecology.

Studying damselfishes of the genus Stegastes from both high disturbance (Jamaica) and low disturbance (Barbados) coral reef environments, Sean Mullen and coauthors searched for evidence of hybridisation among species based on both morphological variation and discordance between mitochondrial and nuclear genetic markers.

Because the damselfishes exhibited strong substrate preferences and aggressive territoriality, the authors hypothesised that species boundaries are maintained by ecological isolation.

Once the reef habitat became more uniform as a result of disturbance and the species isolation mechanism was eliminated, they expected hybridisation between species to be more widespread.

They found this to be indeed the case for the reef habitats in Jamaica, where intense hurricanes have led to considerable habitat degradation over the last 30 years.

If hurricanes are indeed the cause for this hybridisation and given that tropical storms are predicted to increase in intensity over the next century, the authors expect climate change to lead to a further blurring of ecological species boundaries and represent an increasingly common yet underappreciated threat to many coral reef fish species.

For more information, see the paper: Mullen, SP, K Little, M Draud, J. Brozek and M Itzkowitz (2012) Hybridization among Caribbean damselfish species correlates with habitat degradation. Journal of Experimental Marine Biology and Ecology doi:10.1016/j.jembe.2012.01.002

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