February 1st to 5th 2016
Olhão, Portugal
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Temporal behavior of the population genetic structure of Nucella lapillus in the intertidal coast of Galicia (NW Spain)

Scientific Exhibition
Habitat Loss and Ocean Noise
Thursday, February 4, 2016 -
17:30 to 19:30

Carro, B. 1 Quintela, M. 2 Ruiz, J.M. 3 Barreiro, R. 4

1BIOCOST Research Group, Facultade de Ciencias, Universidade da Coruña, Spain
2Dept. of Population Genetics, Institute of Marine Research, Bergen, Norway
3BIOCOST Research Group, Facultade de Ciencias, Universidade da Coruña, Spain
4BIOCOST Research Group, Facultade de Ciencias, Universidade da Coruña, Spain

The dogwhelk Nucella lapillus is a common predator in the rocky intertidal of the European Atlantic. Its females are sterilized by TBT, a powerful biocide released by antifouling paints that was a serious issue in coastal areas around the world due to the heavy maritime traffic. Although banned today, TBT exposure led to the collapse of some populations in the recent past. The rocky shore is a habitat particularly subjected to natural and anthropogenic pressures where population survival can greatly rely on the ability to recruit new individuals from adjacent sources. In this regard, N. lapillus is a direct developer with low dispersal ability. In a previous study, we found that the pattern and amount of individual exchange among populations varies with wave exposure. In sheltered coasts, N. lapillus fitted an isolation-by-distance (IBD) pattern, while its populations were chaotically connected and more strongly differentiated in open coasts. Nonetheless, our study involved a single sampling survey and we could not discriminate whether the unordered genetic pattern was a consequence of restricted dispersal in open coasts or, conversely, whether the stronger water movement actually promotes unordered exchanges among populations that result in the chaotic genetic pattern. Here, we show a new study where both subadults and juveniles were sampled and genotyped two years after the first survey. Both surveys revealed a similar chaotic pattern. However, there was a significant genetic differentiation between generations sampled at the same place in different years (first survey subadults vs. second survey subadults), but not between generations collected within the same year (subadults vs. juveniles). Our results seem consistent with a model where dispersal is restricted in open coasts but only a small, variable fraction of the population produces successful recruits each year.
keywords: 
Nucella lapillus, rocky intertidal, wave exposure, dispersal ability, temporal genetic structure

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