Summary 1.We introduce a novel method that analyses environmental filtering of plant species in a geographic and phylogenetic context. By connecting species traits with phylogeny, traits with environment, and environment with geography, this comprehensive approach partitions the ecological and evolutionary processes that influence community assembly. 2. Our analysis extends RLQ ordination, which connects site attributes in matrix R (here environmental variables and spatial positions) with species attributes in matrix Q (here biological traits and phylogenetic positions), through the composition of sites in terms of species presences or abundances (matrix L). This methodology, which explores and identifies environmental filters that organize communities, was developed to answer four questions: which combinations of trait states are filtered by the environment, which lineages are affected by these filters, which environmental variables contribute to the assemblage of local communities and where do these filters act? 3. At La Mafragh in north-eastern Algeria, our approach shows that plant species traits were distributed according to environmental filters associated with a salinity gradient. Traits associated with the salinity gradient were convergent among Juncaceae, Cyperaceae and Amaranthaceae. The observed phylogenetic and trait patterns were related to how species survived the xeric season. Juncaceae and Cyperaceae, being perennials and anemogamous, tolerate the xeric hot season by restricting their range to the humid centre of the study area (where conditions are close to a subtropical climate). Several Amaranthaceae species co-occur with the Juncaceae and Cyperaceae in two areas with the highest salinity. Most dicots were observed at higher elevations (up to 7 m a.s.l.), had hairy structures that can retain water and reflect solar radiation and were mostly annual or biennial, completing their life cycle before the onset of the xeric season. 4. Synthesis. Our methodology describes environmental filters in terms of identified combinations of traits and environmental factors. It allows spatial and phylogenetic signals to be determined by identifying convergent and conserved patterns in the evolution of traits and spatial scales that structured the environment. Our statistical framework is generic and can be readily extended to a wide range of exciting issues, such as host-parasite, plant-pollinator and predatorprey interactions.

Abstract:A study was undertaken in 2010 to identify Important Plant Areas (Key Biodiversity Areas for Plants) in the south and east Mediterranean region, in order to prioritise the best sites for plant conservation action. It follows a first work of identification of Important Plant Areas (IPAs) initiated for Algeria and relates exclusively to the flora of northern Algeria. These IPAs were delineated in northern Algeria for those sites harbouring a number of "IPA selection species" (threatened species and locally endemic or restricted range). Recent taxonomic revisions estimate the number of national endemics for the north of Algeria (excluding the Sahara) to be over 300 taxa. In the present study, data were extracted from the global list of 22 IPAs identified for the north of Algeria. The species considered are i) threatened species as defined by the 1997 IUCN global red list of plants, ii) locally endemic species, iii) nationally threatened species. Trigger species, identified by combining the criteria of endemism and rarity, are mainly Algerian national endemics but also include some AlgerianMoroccan and Algerian-Tunisian endemics. One hundred and fifty two (152) trigger species were identified and these species, which have high ecological value, can be used to characterize the particular floristic interest of a site and can therefore be a useful tool for conservation purposes. Important gaps in knowledge have been highlighted, in particular those relating to taxonomy and the lack of up-to-date field data. It is therefore essential to undertake in situ research in order to better understand the distribution and status of these species. A flexible approach to identifying and recognising priority sites for plants using surrogate criteria, supplemented by expert opinion, alongside existing globally standardised criteria, is therefore essential if the most important sites for plant diversity are to receive the conservation attention they deserve.

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´tude phytoe ´cologique des aulnaies du nord-est alge ´rien montre que ces habitats d'affinite ´septentrionale pre ´sentent une tre `s grande richesse spe ´cifique (> 400 espe `ces) et une structure complexe, qui plaident pour leur origine ancienne. Sur le plan phytosociologique, elles sont rattache ´es a `deux syntaxons, le Campanulo alatae-Alnenion glutinosae (aulnaies riveraines) et le Rusco hypophylli-Alnetum glutinosae (aulnaies mare ´cageuses). Leur e ´tat de de ´gradation et leur dynamique re ´gressive, observe ´es au cours des 14 anne ´es de l'e ´tude, re ´ve `lent leur statut extre ˆmement pre ´caire et leur de ´clin rapide sous l'influence de perturbations anthropiques incontro ˆle ´es (de ´frichement, incendies, drainage, pollution. . .). Au vu de leur importance e ´cologique, historique et patrimoniale, les aulnaies de Numidie alge ´rienne doivent rapidement faire l'objet de mesures de protection, dans le but d'assurer la pe ´rennite ´des corte `ges floristiques exceptionnels qui les constituent.

Wetlands deserve a number of functions, comprising inundation control, groundwater recharge, chemical trapping and nutrient recycling, and harbour remarkable C. R. Biologies 334 (2011) 757-772