Rafael G. Albaladejo | Universidad de Sevilla (original) (raw)

Papers by Rafael G. Albaladejo

Botanica Complutensis, 2013

Journal of Applied Ecology, 2015

1. Environmental stochasticity and low demographic rates may cause delayed extinctions of habitat... more 1. Environmental stochasticity and low demographic rates may cause delayed extinctions of habitat-specialist species that were initially retained within remnant patches after habitat loss and fragmentation. Detecting such extinction debts opens opportunities to counteract future biodiversity loss, yet knowing the underlying causes of population declines is a basic need for targeting specific guidelines for conservation and restoration (e.g. habitat quantity, quality or connectivity). 2. Here, we examine the extinction debt in the common Mediterranean shrub Myrtus communis (myrtle) occurring in woodland patches of a highly fragmented region that has lost nearly half of the remnant woodland cover during the last 50 years . 3. We sampled myrtle occurrence in 304 woodland patches and modelled its probability of occurrence in relation to patch size, patch disturbance and woodland cover in the surrounding landscape. In order to test for extinction debt evidence, we tested whether myrtle occurrence is better predicted by past (1956) than by present woodland cover. 4. We found that the probability of myrtle occurrence is associated with present patch features (size and disturbance) that are linked to causes of individual mortality and/or recruitment collapse. However, it was associated with pastrather than presentwoodland cover in the surrounding landscape, proving a still unpaid extinction debt. Specifically, myrtle occurrence is very unlikely in small and highly disturbed patches located in long-term deforested landscapes. 5. Synthesis and applications. Individual longevity of the Mediterranean shrub Myrtus communis (myrtle) can delay local extinctions, but paying the debt is a matter of time, especially considering the elevated susceptibility of small and disturbed populations to environmental stochasticity. However, these populations still offer management opportunities, and reducing disturbances and improving habitat quality, especially within small woodland patches, should be a top priority for conservation and restoration.

Plant Biology, 2014

Studies concerning different habitat configurations can provide insights into the complex interac... more Studies concerning different habitat configurations can provide insights into the complex interactions between species' life-history traits and the environment and can help to predict patterns in population genetics. In this study, we compared patterns of genetic variation in two Mediterranean shrub species (Myrtus communis and Pistacia lentiscus) that co-occur in populations within three contrasting landscape contexts: continuous, fragmented-connected and fragmented-isolated populations. Analysing variation at microsatellites loci, our results revealed weak responses to the landscape contexts. We rather found a population-specific response in both study species. However, despite both study species sharing similar levels of genetic diversity, Myrtus displayed higher levels of homozygosity and genetic differentiation among populations, stronger patterns of within-population spatial genetic structure, lower values of mutation-scaled effective population size and stronger evidence for recent genetic bottlenecks than Pistacia. This result highlights the influence of past events (e.g. historical connectivity, fluctuations in population size) and local factors (e.g. microhabitat availability for recruitment, habitat quality, plant density, native fauna) and that the landscape configuration per se (i.e. fragment size and/or isolation) might not completely determine the species' genetic patterns.

Phlomisimargaritae is a rare and sterile hybrid taxon found in a single endangered population in ... more Phlomisimargaritae is a rare and sterile hybrid taxon found in a single endangered population in southern Spain. It was previously described as a morphologically intermediate hybrid, putatively between Phlomis purpurea and P. composita. The present study used allozymes as molecular markers to assess the hybrid identity of P.imargaritae. Ten putative loci from seven enzyme systems were resolved : five were monomorphic and fixed across all taxa studied and the rest (Aat-1, Aat-2, 6-Pgdh-2, Pgi and Pgm) were polymorphic in at least one taxon. The two parental taxa are fixed for different alleles at 6-Pgdh-2 and show distinct allelic frequency differences for four other loci. Phlomisimargaritae displays fixed heterozygous phenotypes for four of the five polymorphic loci, these being composed of combinations of the alleles found in the parental taxa. No unique alleles were detected in P.imargaritae. We conclude that this taxon is of hybrid origin and confirm the identity of the parental taxa involved.

Aims The historical influence of gene flow and genetic drift after the last glacial phase of the ... more Aims The historical influence of gene flow and genetic drift after the last glacial phase of the Quaternary Period is reflected in current levels of genetic diversity and population structure of plant species. Moreover, hybridization after secondary contact might also affect population genetic diversity and structure. An assessment was made of the genetic variation and hybrid zone structure in Iberian populations of the Mediterranean Phlomis lychnitis and P. crinita, for which phylogenetic relationships are controversial, and hybridization and introgression are common. † Methods Allozyme variation at 13 loci was analysed in 1723 individual plants sampled from 35 natural locations of P. lychnitis, P. crinita subsp. malacitana and P. crinita subsp. crinita in southern and eastern Spain. Standard genetic diversity parameters were calculated and patterns of genetic structure in each taxon were tested to fit the equilibrium between gene flow and genetic drift. Individual multilocus genotypes were subjected to Bayesian clustering analysis to estimate hybridization and introgression rates for both geographic regions. † Key Results Contrasting patterns in the distribution of genetic variation among the three taxa were found. Phlomis lychnitis showed no significant inbreeding, low genetic differentiation among populations and no evidence of isolation by distance. Phlomis crinita subsp. malacitana and P. crinita subsp. crinita showed high levels of genetic structure consistent with a pattern of gene flow-drift equilibrium. Higher instances of hybridization and introgression were detected in locations from southern Spain compared with locations from eastern Spain, matching unimodal and bimodal hybrid zones, respectively. † Conclusions High instances of historical gene flow, range expansion and altitudinal movement during the Quaternary Period, and lineage sorting can explain the diversity of patterns observed. The results suggest that P. lychnitis is the most differentiated lineage in the group; however, the relationship between the three taxa remains unclear.

Aim The geographic clinal variation of traits in organisms can indicate the possible causes of ph... more Aim The geographic clinal variation of traits in organisms can indicate the possible causes of phenotypic evolution. We studied the correlates of flower trait variation in populations of a style-dimorphic plant, Narcissus papyraceus Ker-Gawl., within a region of high biogeographical significance, the Strait of Gibraltar. This species shows a geographic gradient in the style-morph ratio, suggested to be driven by pollinator shifts. We tested whether parallel geographic variation of perianth traits also exists, concomitant with vegetative trait variation or genetic similarity of plant populations. Location The Strait of Gibraltar region (SG hereafter, including both south- western Iberian Peninsula and north-western Morocco). Methods We used univariate and multivariate analyses of flower and vegetative traits in 23 populations. We applied Mantel tests and partial Mantel correlations on vegetative and flower traits and geographic locations of populations to test for spatial effects. We...

Proceedings of the National Academy of Sciences, 2009

Spatial patterns of genetic variation provide information central to many ecological, evolutionar... more Spatial patterns of genetic variation provide information central to many ecological, evolutionary, and conservation questions. This spatial variability has traditionally been analyzed through summary statistics between pairs of populations, therefore missing the simultaneous influence of all populations. More recently, a network approach has been advocated to overcome these limitations. This network approach has been applied to a few cases limited to a single species at a time. The question remains whether similar patterns of spatial genetic variation and similar functional roles for specific patches are obtained for different species. Here we study the networks of genetic variation of four Mediterranean woody plant species inhabiting the same habitat patches in a highly fragmented forest mosaic in Southern Spain. Three of the four species show a similar pattern of genetic variation with well-defined modules or groups of patches holding genetically similar populations. These modules can be thought of as the long-sought-after, evolutionarily significant units or management units. The importance of each patch for the cohesion of the entire network, though, is quite different across species. This variation creates a tremendous challenge for the prioritization of patches to conserve the genetic variation of multispecies assemblages.

Plant Systematics and Evolution, 2002

Journal of Biogeography, 2009

Journal of Applied Ecology, 2010

1. The long-term persistence of fragmented plant populations is predicted to be threatened by a l... more 1. The long-term persistence of fragmented plant populations is predicted to be threatened by a loss of genetic variability and increasing inbreeding, which might lower offspring fitness through inbreeding depression. Assessing plant progeny performance together with measurements of genetic diversity and mating patterns is therefore essential in the understanding of the role of the historical (i.e. genetic diversity in adults) and contemporary (i.e. current mating patterns) genetic effects of fragmentation on inbreeding depression, thus, on recruitment potential. 2. We evaluated genetic diversity, mating patterns and progeny performance at different life stages in seven populations of a Mediterranean shrub (myrtle Myrtus communis) that differed in size and degree of isolation (Large, Small-connected and Small-isolated populations). The study was conducted in the Guadalquivir Valley (SW Spain), a chronically and severely fragmented landscape characterized by c. 1% of woodland cover. 3. Parameters of genetic diversity (A r , H o and H e ) of adult plants were in general higher in the Large populations than in the two types of Small populations, which were similar. Outcrossing rates were higher in Small-connected populations (mean: t m = 0AE62), intermediate in Large (t m = 0AE35) and lower in Small-isolated populations (t m = 0AE13), and were positively correlated with the genetic diversity of progenies. 4. Several measurements of progeny performance were higher in Small-connected populations, intermediate in Large and lower in Small-isolated populations, in particular those related with the quantity of viable seedlings produced (germination and survival). Outcrossing rates rather than the genetic diversity of adult plants were positively correlated with these measurements of progeny performance. 5. We thus conclude that contemporary mating patterns (outcrossing rates) have a more critical influence on progeny performance than either population fragmentation or the historical levels of genetic diversity. 6. Synthesis and applications. It may be possible to enhance either the fitness or certain levels of genetic diversity in progenies by promoting outcrossed matings in fragmented populations of selfcompatible plant species. In our study species, this would be feasible either by controlling honeybee Apis mellifera hives or maintaining and ⁄ or enhancing landscape connectivity around small patches.

Diversity and Distributions, 2012

Aim The effect of habitat fragmentation on population genetic structure results from the interact... more Aim The effect of habitat fragmentation on population genetic structure results from the interaction between species' life history traits and the particular landscape context, and both components are inherently difficult to tease apart. Here, we compare the genetic (allozyme) structure of four co-occurring woody species with contrasting life histories to explore how well their response to the same fragmentation process can be predicted from their functional traits.

Botanical Journal of the Linnean Society, 2004

Hybridization seems to be common in the genus Phlomis (Lamiaceae) in the Iberian Peninsula, espec... more Hybridization seems to be common in the genus Phlomis (Lamiaceae) in the Iberian Peninsula, especially in the P. ¥ composita complex. In order to detect patterns of morphological variation linked to eco-and geographical variation, ecological (cluster and canonical correspondence) and morphometric (principal component and discriminant function) analyses were performed. Character count procedure was applied to discern between divergence and reticulate events for the origin of the morphologically intermediate plants. Following these analyses clear patterns were detected suggesting the existence of four independent morphological groups also supported by the ecogeographical data. These are P. crinita ssp. crinita (Levante, eastern Spain), P. crinita ssp. malacitana (Andalusia, southern Spain) and P. lychnitis (widespread) being the extremes of the morphological variation, and P. ¥ composita including all the morphologically intermediate individual plants. Furthermore, at the population level significant differences in hybrid plant frequencies between areas were also found.

Botanical Journal of the Linnean Society, 2003

The extent of chromosome structural differences such as permanent translocations and paracentric ... more The extent of chromosome structural differences such as permanent translocations and paracentric inversions has been studied in the hybrid complex of Phlomis composita and its putative parental taxa P. lychnitis and P. crinita . They are detected as meiotic abnormalities during microsporogenesis. In total, 117 plants from 19 populations in Andalusia (southern Spain) and Levante (eastern Spain) were studied for ploidy level, chromosome clumping, multivalent or univalent formation, late bivalent disjunction with bridges, chromatin bridges and fragments, irregular polysporads and variable pollen size. All individuals had the diploid chromosome number 2 n = 20, with no significant difference in the frequencies of the above meiotic abnormalities either at taxon or population levels. However, very different frequencies were observed on the regional scale between populations in Andalusia and Levante. The results are discussed within the theoretical framework of homoploid hybrid or recombinational speciation.

Biological Journal of the Linnean Society, 2007

The region around the Strait of Gibraltar is considered to be one of the most relevant 'hot spots... more The region around the Strait of Gibraltar is considered to be one of the most relevant 'hot spots' of biodiversity in the Mediterranean Basin due to its historical, biogeographical, and ecological features. Prominent among these is its role as a land bridge for the migration and differentiation of species during the Pleistocene, as a consequence of the lowering of sea level and climate changes associated with the Ice Ages. In the present study, we report a multilevel hierarchical investigation of the genetic diversity of Calicotome villosa, a common pioneer legume shrub, at the regional scale. The results of genetic analysis of progeny arrays are consistent with a predominantly outcrossing mating system in all the populations analysed. Geographically, a pattern of population isolation by distance was found, but the Strait accounted for only approximately 2% of the among-population genetic differentiation. Consequently, extensive historical gene flow appears to be the rule for this species in this area. According to the natural history traits of C. villosa (pollination, dispersal, and colonization ability), we hypothesize that gene flow must be strongly influenced by seed dispersal because pollen flow is very limited. Based on the history of trade and land use, cattle and human movements across the Strait must have strongly favoured seed dispersal. We review and discuss these results and compare them with those of other reported studies of genetic and phylogenetic differentiation across the Strait of Gibraltar. It is stressed that colonization ability, which depends upon seed dispersal and life form, can be a more critical factor in gene flow than pollination.

Ecosistemas, 2012

Estas personas contribuyeron generosamente a revisar los manuscritos recibidos en ECOSISTEMAS dur... more Estas personas contribuyeron generosamente a revisar los manuscritos recibidos en ECOSISTEMAS durante el año 2011. Agradecemos a todos ellos su desinteresada colaboración. ... Adrián Escudero Ainhoa Magrach Alicia Valdés Arturo Cortés Maldonado Beatriz Pérez Cristina García Daniel García Daniel Martínez Exequiel Ezcurra Fernando Madrid Fernando Valladares Francisco Pugnaire Francisco Rodríguez Gregorio Aragón Javier Benayas Javier Pérez-Trís Javier Rodríguez-Pérez Jessica Lavabre Jordi Cortina José Luis Quero José Maria Iriondo José María Sánchez ...

This article documents the addition of 228 microsatellite marker loci to the Molecular Ecology Re... more This article documents the addition of 228 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Samanea saman. These loci were cross-tested on the following species: Apodemus sylvaticus, Laricobius laticollis and Laricobius osakensis (a proposed new species currently being described).

PLoS ONE, 2012

Analysing pollen movement is a key to understanding the reproductive system of plant species and ... more Analysing pollen movement is a key to understanding the reproductive system of plant species and how it is influenced by the spatial distribution of potential mating partners in fragmented populations. Here we infer parameters related to levels of pollen movement and diversity of the effective pollen cloud for the wind-pollinated shrub Pistacia lentiscus across a highly disturbed landscape using microsatellite loci. Paternity analysis and the indirect KinDist and Mixed Effect Mating models were used to assess mating patterns, the pollen dispersal kernel, the effective number of males (N ep ) and their relative individual fertility, as well as the existence of fine-scale spatial genetic structure in adult plants. All methods showed extensive pollen movement, with high rates of pollen flow from outside the study site (up to 73-93%), fat-tailed dispersal kernels and large average pollination distances (d = 229-412 m). However, they also agreed in detecting very few pollen donors (N ep = 4.3-10.2) and a large variance in their reproductive success: 70% of males did not sire any offspring among the studied female plants and 5.5% of males were responsible for 50% of pollinations. Although we did not find reduced levels of genetic diversity, the adult population showed high levels of biparental inbreeding (14%) and strong spatial genetic structure (S p = 0.012), probably due to restricted seed dispersal and scarce safe sites for recruitment. Overall, limited seed dispersal and the scarcity of successful pollen donors can be contributing to generate local pedigrees and to increase inbreeding, the prelude of genetic impoverishment. Citation: Albaladejo RG, Guzmán B, González-Martínez SC, Aparicio A (2012) Extensive Pollen Flow but Few Pollen Donors and High Reproductive Variance in an Extremely Fragmented Landscape. PLoS ONE 7(11): e49012.

Plant Ecology, 2009

Mate abundance is one of the most important sources of variation in plant mating systems. We exam... more Mate abundance is one of the most important sources of variation in plant mating systems. We examined within-population heterogeneity in the pollen pool at two spatial scales (sites and plants), and investigated the mating pattern variation in Myrtus communis under diverse situations of conspecific neighbourhood, using allozyme electrophoresis of naturally pollinated progeny arrays. For mating analyses, plants sampled were classified into four neighbourhood groups (from high to low) based on the local density around them and the distance to their nearest neighbour. The pollen pool was much more genetically heterogeneous among mother plants (*21%) than among sites (*2%), probably because of the high levels of selfing found (average s = 0.65). Outcrossing rates differed significantly among neighbourhood groups and showed a marked trend towards higher values from the lowest (t m = 0.26) to the highest (t m = 0.45) degree of conspecific aggregation. However, the lowest levels of biparental inbreeding and correlated paternity were found in the most isolated group of plants, indicating that these plants crossed with more and less genetically related fathers. Our study provides a clear demonstration of positive correlation between conspecific aggregation and the outcrossing rates. We discuss the ecological implications of these results in the context of Mediterranean ecosystems.