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Ortego J.,EBD Group | Ortego J.,Institute Investigacion en Recursos Cinegeticos IREC CSIC | Gugger P.F.,University of California at Los Angeles | Sork V.L.,University of California at Los Angeles
Journal of Biogeography

Aim: We studied which factors shape contemporary patterns of genetic structure, diversity and admixture in the canyon live oak (Quercus chrysolepis). Specifically, we tested two alternative hypotheses: (1) that areas with high habitat suitability and stability since the Last Glacial Maximum (LGM) sustain higher effective population sizes, resulting in increased levels of genetic diversity; and (2) that populations from areas with lower habitat stability show higher levels of genetic admixture due to their recurrent colonization by individuals originating from genetically differentiated populations. Furthermore, we analysed the relative importance of past and current habitat suitability and their additive effects on contemporary patterns of genetic structure. Location: California, USA. Methods: We sampled 160 individuals from 33 localities across the distribution range of the canyon live oak in California and then combined information from 13 nuclear microsatellite DNA markers and climate niche modelling to study patterns of genetic variation in this species. We used Bayesian clustering analyses to analyse geographical patterns of genetic structure and admixture, and circuit theory to generate isolation-by-resistance (IBR) distance matrices. Results: We found that the degree of genetic admixture was higher in localities with lower inferred population stability, but that genetic diversity was not associated with habitat suitability or stability. Landscape genetic analyses identified habitat stability as the primary driver of population genetic differentiation. Main conclusions: This study shows that habitat stability can be a major factor shaping genetic variation in wind-pollinated trees and supports the idea that stable regions contribute to genetic connectivity across different climatic periods. To our knowledge, this study is the first to report an association between patterns of genetic admixture and stability of local habitat. © 2015 John Wiley & Sons Ltd. Source

Ortego J.,CSIC - National Museum of Natural Sciences | Bonal R.,Institute Investigacion en Recursos Cinegeticos IREC CSIC | Munoz A.,Institute Recursos Naturales
Journal of Heredity

Large-scale forest fragmentation can increase interpopulation genetic differentiation and erode the genetic variability of remnant plant populations. In this study, we analyze the extent of clonality and the genetic variability and structure within a holm oak (Quercus ilex) population from Central Spain at 3 patches showing different degrees of fragmentation. For this purpose, we have typed 191 individuals (105 adults and 86 saplings) at 9 microsatellite loci. Microsatellite markers revealed an extensive clonal structure in this species, with most analyzed clumps constituting a single "genet", which in some cases extended over a considerable area (up to 318 m2). The maximum distance between "ramets" tended to be higher in the extremely fragmented patch, suggesting that intensive management and environmental perturbation has favored clonal propagation. We have also found evidence that fragmentation has contributed to reduce genetic variability and increase genetic differentiation in holm oak saplings, indicating that the younger cohorts are suffering some negative genetic consequences of long-term population fragmentation. Finally, analyses of fine spatial genetic structure have revealed significant kinship structures up to 20-50 m that were particularly patent in the 2 less fragmented patches. Overall, our findings point to long-term genetic shifts in population structure of holm oaks in fragmented landscapes; however, further research is required on pollen dispersal and gene flow in this species. © 2010 The American Genetic Association. All rights reserved. Source

Perez-Granados C.,University of Alicante | Serrano-Davies E.,University of Castilla - La Mancha | Noguerales V.,Institute Investigacion en Recursos Cinegeticos IREC CSIC
Revista Catalana d'Ornitologia

The progressive loss of natural wetlands throughout Europe has led to the use of human infrastructures such as gravel pits, irrigation ponds and reservoirs by waterbirds as an alternative habitat. In Central Spain, the presence of man-made wetlands is essential for waterfowl conservation. The temporal dynamics of the wintering waterbird community was studied in an artificial wetland located in Madrid, Central Spain (Laguna de Meco). We carried out fortnightly censuses between October 2011 and February 2012 (total of 10) to describe variations in patterns of abundance and of species and taxonomic group richness. A total of 27 aquatic species and 2,901 birds were recorded. Diversity, number of birds and species richness varied between months. The highest numbers of birds occurred in October and February, while the greatest diversity and species richness were recorded during the postnuptial migration in October and November due to the large number of shorebirds occurring in those months. The most abundant species over the study period was the Common Coot Fulica atra, with 38% of the total birds counted, the only exception being the last half of February when the Black-headed Gull Chroicocephalus ridibundus was commonest. Despite only having been created in 2008, this lagoon hosts one of the most important waterfowl communities in Madrid and plays a crucial role in shorebird migration and waterbird conservation in the area. The information provided here could be useful for management strategies in this artificial wetland, which include protecting the lagoon and discarding the idea of moving it to a nearby area. Source

Ortego J.,CSIC - Donana Biological Station | Garcia-Navas V.,University of Zurich | Noguerales V.,Institute Investigacion en Recursos Cinegeticos IREC CSIC | Cordero P.J.,Institute Investigacion en Recursos Cinegeticos IREC CSIC
Molecular Ecology

Conservation plans can be greatly improved when information on the evolutionary and demographic consequences of habitat fragmentation is available for several codistributed species. Here, we study spatial patterns of phenotypic and genetic variation among five grasshopper species that are codistributed across a network of microreserves but show remarkable differences in dispersal-related morphology (body size and wing length), degree of habitat specialization and extent of fragmentation of their respective habitats in the study region. In particular, we tested the hypothesis that species with preferences for highly fragmented microhabitats show stronger genetic and phenotypic structure than codistributed generalist taxa inhabiting a continuous matrix of suitable habitat. We also hypothesized a higher resemblance of spatial patterns of genetic and phenotypic variability among species that have experienced a higher degree of habitat fragmentation due to their more similar responses to the parallel large-scale destruction of their natural habitats. In partial agreement with our first hypothesis, we found that genetic structure, but not phenotypic differentiation, was higher in species linked to highly fragmented habitats. We did not find support for congruent patterns of phenotypic and genetic variability among any studied species, indicating that they show idiosyncratic evolutionary trajectories and distinctive demographic responses to habitat fragmentation across a common landscape. This suggests that conservation practices in networks of protected areas require detailed ecological and evolutionary information on target species to focus management efforts on those taxa that are more sensitive to the effects of habitat fragmentation. © 2015 John Wiley & Sons Ltd. Source

Ortego J.,CSIC - Donana Biological Station | Aguirre M.P.,Institute Investigacion en Recursos Cinegeticos IREC CSIC | Noguerales V.,Institute Investigacion en Recursos Cinegeticos IREC CSIC | Cordero P.J.,Institute Investigacion en Recursos Cinegeticos IREC CSIC
Evolutionary Applications

Anthropogenic habitat fragmentation has altered the distribution and population sizes in many organisms worldwide. For this reason, understanding the demographic and genetic consequences of this process is necessary to predict the fate of populations and establish management practices aimed to ensure their viability. In this study, we analyse whether the spatial configuration of remnant semi-natural habitat patches within a chronically fragmented landscape has shaped the patterns of genetic diversity and structure in the habitat-specialist esparto grasshopper (Ramburiella hispanica). In particular, we predict that agricultural lands constitute barriers to gene flow and hypothesize that fragmentation has restricted interpopulation dispersal and reduced local levels of genetic diversity. Our results confirmed the expectation that isolation and habitat fragmentation have reduced the genetic diversity of local populations. Landscape genetic analyses based on circuit theory showed that agricultural land offers ~1000 times more resistance to gene flow than semi-natural habitats, indicating that patterns of dispersal are constrained by the spatial configuration of remnant patches of suitable habitat. Overall, this study shows that semi-natural habitat patches act as corridors for interpopulation gene flow and should be preserved due to the disproportionately large ecological function that they provide considering their insignificant area within these human-modified landscapes. © 2015 The Authors. Source

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