Comparative Analysis of Stability-Genetic Diversity in Seagrass (Posidonia oceanica) Meadows Yields Unexpected Results

Type Article
Date 2010-07
Language English
Author(s) Arnaud-Haond SophieORCID1, 2, Marba Nuria3, Diaz-Almela Elena3, Serrao Ester A.2, Duarte Carlos M.3
Affiliation(s) 1 : IFREMER, Lab Environm Profond Ctr Brest, F-29280 Plouzane, France.
2 : Univ Algarve, Lab MAREE CCMAR, CIMAR Lab Associado, P-8005139 Faro, Portugal.
3 : IMEDEA CSIC UIB, Dept Global Change Res, Esporles 07190, Mallorca, Spain.
Source Estuaries And Coasts (1559-2723) (Springer), 2010-07 , Vol. 33 , N. 4 , P. 878-889
DOI 10.1007/s12237-009-9238-9
WOS© Times Cited 41
Keyword(s) Seagrass, Demography, Clonality, Genetic richness, Diversity-stability, Posidonia oceanica
Abstract The diversity-stability relationship is the subject of a long-standing debate in ecology, but the genetic component of diversity has seldom been explored. In this study, we analyzed the interplay between genetic diversity and demographic responses to environmental pressures. This analysis included 30 meadows formed by the Mediterranean endemic seagrass, Posidonia oceanica, showing a wide range of population dynamics ranging from a near equilibrium state to steep decline due to strong environmental pressures close to aquaculture installations. Our results show that sedimentation rates are much better predictors of mortality than clonal or genetic components. An unexpected positive trend was observed between genotypic diversity and mortality, along with a negative relationship between allelic richness and net population growth. Yet such trends disappeared when excluding the most extreme cases of disturbance and mortality, suggesting the occurrence of a threshold below which no relationship exists. These results contrast with the positive relationship between genotypic diversity and resistance or resilience observed in previous manipulative experiments on seagrass. We discuss the reasons for this discrepancy, including the difficulties in designing experiments reflecting the complexity of natural meadows.
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