title: Genetic patterns of habitat fragmentation and past climate-change effects in the Mediterranean high-mountain plant Armeria caespitosa (Plumbaginaceae).
abstract: OBJECTIVE
  Mountain plants are among the species most vulnerable to global warming, because of their isolation, narrow geographic distribution, and limited geographic range shifts. Stochastic and selective processes can act on the genome, modulating genetic structure and diversity. Fragmentation and historical processes also have a great influence on current genetic patterns, but the spatial and temporal contexts of these processes are poorly known. We aimed to evaluate the microevolutionary processes that may have taken place in Mediterranean high-mountain plants in response to changing historical environmental conditions.
  
  
  METHODS
  Genetic structure, diversity, and loci under selection were analyzed using AFLP markers in 17 populations distributed over the whole geographic range of Armeria caespitosa, an endemic plant that inhabits isolated mountains (Sierra de Guadarrama, Spain). Differences in altitude, geographic location, and climate conditions were considered in the analyses, because they may play an important role in selective and stochastic processes.
  
  
  RESULTS
  Bayesian clustering approaches identified nine genetic groups, although some discrepancies in assignment were found between alternative analyses. Spatially explicit analyses showed a weak relationship between genetic parameters and spatial or environmental distances. However, a large proportion of outlier loci were detected, and some outliers were related to environmental variables.
  
  
  CONCLUSIONS
  A. caespitosa populations exhibit spatial patterns of genetic structure that cannot be explained by the isolation-by-distance model. Shifts along the altitude gradient in response to Pleistocene climatic oscillations and environmentally mediated selective forces might explain the resulting structure and genetic diversity values found.
authors.affiliation: Universidad Rey Juan Carlos, C\Tulipán SN 28933 Móstoles, Madrid, Spain. alfredo.garcia@urjc.com
authors.forename: Alfredo
authors.initials: A
authors.lastname: García-Fernández
authors.forename: Jose M
authors.initials: JM
authors.lastname: Iriondo
authors.forename: Adrián
authors.initials: A
authors.lastname: Escudero
authors.forename: Javier Fuertes
authors.initials: JF
authors.lastname: Aguilar
authors.forename: Gonzalo Nieto
authors.initials: GN
authors.lastname: Feliner
mesh_terms: D000531:Altitude; D054458:Amplified Fragment Length Polymorphism Analysis; D002980:Climate; D057231:Climate Change; D017753:Ecosystem; D051456:Gene Flow; D056426:Genetic Loci; D040342:Genetic Structures; D014644:Genetic Variation; D005828:Genetics, Population; D018745:Genome, Plant / Q000235:genetics*; D005843:Geography; D018895:Microsatellite Repeats / Q000235:genetics; D029606:Plumbaginaceae / Q000235:genetics*; D013030:Spain
keywords: climate change; divergent selection; genetic structure; mountain habitat; outlier loci; population genetics; spatial autocorrelation