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Sajeva M.,University of Palermo | La Mantia T.,University of Palermo | Harrouni C.,Hassan II Institute of Agronomy and Veterinary science | Msanda F.,University Ibn Zohr
Molecular Ecology | Year: 2015

Ecological and evolutionary studies largely assume that island populations display low levels of neutral genetic variation. However, this notion has only been formally tested in a few cases involving plant taxa, and the confounding effect of selection on genetic diversity (GD) estimates based on putatively neutral markers has typically been overlooked. Here, we generated nuclear microsatellite and plastid DNA sequence data in Periploca laevigata, a plant taxon with an island-mainland distribution area, to (i) investigate whether selection affects GD estimates of populations across contrasting habitats; and (ii) test the long-standing idea that island populations have lower GD than their mainland counterparts. Plastid data showed that colonization of the Canary Islands promoted strong lineage divergence within P. laevigata, which was accompanied by selective sweeps at several nuclear microsatellite loci. Inclusion of loci affected by strong divergent selection produced a significant downward bias in the GD estimates of the mainland lineage, but such underestimates were substantial (>14%) only when more than one loci under selection were included in the computations. When loci affected by selection were removed, we did not find evidence that insular Periploca populations have less GD than their mainland counterparts. The analysis of data obtained from a comprehensive literature survey reinforced this result, as overall comparisons of GD estimates between island and mainland populations were not significant across plant taxa (N = 66), with the only exception of island endemics with narrow distributions. This study suggests that identification and removal of markers potentially affected by selection should be routinely implemented in estimates of GD, particularly if different lineages are compared. Furthermore, it provides compelling evidence that the expectation of low GD cannot be generalized to island plant populations. © 2015 John Wiley & Sons Ltd.

Jirou Y.,Hassan II Institute of Agronomy and Veterinary science | Harrouni C.,Hassan II Institute of Agronomy and Veterinary science | Arroud A.,University Ibn Zohr | Daoud S.,University Ibn Zohr | And 2 more authors.
Journal of Materials and Environmental Science | Year: 2014

In 2010, a controlled landfill started to receive urban waste generated by the Greater Agadir population. As this waste is rich in organic matter, significant quantities of leachate are produced and stored in ponds built for that purpose. Given the pollution load of the leachate it is important to reduce the concentration of pollutants prior to discharge into the urban sewer network. A study was carried out in 2011 to investigate the treatment of the landfill leachate. The results showed that the level of pollution was significantly reduced but the effluent was highly saline (EC: 33.9 dS/m and chlorides concentration: 10,295 mg/L). This high salinity represents a major limiting factor to any kind of subsequent use or disposal. The purpose of this work was to proceed to the characterization of leachate according to the urban neighbourhoods generating the waste with the aim of identifying the origin of salinity. A comparison of the physicochemical parameters (pH, EC, suspended matter, organic matter, dry residues, BOD5, COD, nitrogen, phosphorous, ions and trace elements) between leachates produced by fresh waste originating from different neighbourhoods showed distinct differences. The main differences lay in the concentration of chlorides and EC with the leachate from the fresh waste generated by the port having higher values compared to leachate produced by fresh waste coming from other neighbourhoods. It is recommended that the waste generated by the port's activities should be treated separately so that it does not contaminate relatively less polluted leachate coming from domestic waste.

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