Acerca de la identidad de Helianthemum mathezii y H. pomeridianum (Cistaceae)

The original description of Helianthemum mathezii regarded the species to be a therophyte. However, the detailed observation of the holotype of H. mathezii, as well as newly collected specimens from the type locality, does not support its condition of annual plant. Further study has led to the conclusion that all these plants can readily be identified as H. pomeridianum; the descriptions of H. mathezii and H. pomeridianum are equivalent except for the habit, being the former annual and the latter suffruticose. We show in this study that H. mathezii is to be considered a synonym of H. pomeridianum, and report a new locality of H. pomeridianum in Morocco. Also, we provide the first chromosome count for this species (2n = 22) which emphasizes the close relationship of H. pomeridianum to H. subgen. Plectolobum.En la descripción original de Helianthemum mathezii se considera esta especie como un terofito. Sin embargo, la observación minuciosa de su holotipo, así como de otros especímenes recientemente recolectados en la misma localidad del tipo, sugiere que no se trata de una planta anual. Concluimos que estas plantas pueden ser bien identificadas como H. pomeridianum; las descripciones de H. mathezii y H. pomeridianum son similares excepto en lo referido a su hábito, la primera supuestamente es una planta anual y la segunda sufruticosa. Así pues, aquí recomendamos considerar H. mathezii como sinónimo de H. pomeridianum, y citamos una localidad nueva de esta especie en Marruecos. Además, damos cuenta del primer recuento de cromosomas efectuado para la misma (2n = 22), que demuestra la estrecha afinidad de H. pomeridianum y H. subgen. Plectolobum

On the identity of <em>Helianthemum mathezii</em> and <em>H. pomeridianum</em> (Cistaceae)

The original description of Helianthemum mathezii regarded the species to be a therophyte. However, the detailed observation of the holotype of H. mathezii, as well as newly collected specimens from the type locality, does not support its condition of annual plant. Further study has led to the conclusion that all these plants can readily be identified as H. pomeridianum; the descriptions of H. mathezii and H. pomeridianum are equivalent except for the habit, being the former annual and the latter suffruticose. We show in this study that H. mathezii is to be considered a synonym of H. pomeridianum, and report a new locality of H. pomeridianum in Morocco. Also, we provide the first chromosome count for this species (2n = 22) which emphasizes the close relationship of H. pomeridianum to H. subgen. Plectolobum

Genetic diversity and differentiation in narrow versus widespread taxa of Helianthemum (Cistaceae) in a hotspot: The role of geographic range, habitat, and reproductive traits

We thank the authorities of the Sierra Nevada National Park and the Junta de Andalucía (Andalusian Regional Government) for granting permission to collect samples even of species under protection. We also thank the Centro de Investigación Tecnología e Innovación de la Universidad de Sevilla (“Celestino Mutis” CITIUS-2 center) for facilities to use the Coulter Multisizer 3. This research was supported by grants from the Ministerio de Agricultura, Alimentación y Medio Ambiente (National Parks Authority ref. 296/2011) and by the Ministerio de Economía y Competitividad (CGL2014-52459-P and partially CGL2013-45037-P and CGL2017-82465-P). S. MartínHernanz was supported by a fellowship from the Spanish Secretaría de Estado de Investigación, Desarrollo e Innovación (FPI 2015, BES-2015-073314). All samples in this study were collected under permission by the Sierra Nevada National Park and the Andalusian Regional GovernmentUnraveling the relationships between ecological, functional traits and genetic diversity of narrow endemic plants provide opportunities for understanding how evolutionary processes operate over local spatial scales and ultimately how diversity is created and maintained. To explore these aspects in Sierra Nevada, the core of the Mediterranean Betic‐Rifean hotspot, we have analyzed nuclear DNA microsatellite diversity and a set of biological and environmental factors (physicochemical soil parameters, floral traits, and community composition) in two strictly endemic taxa from dolomite outcrops of Sierra Nevada (Helianthemum pannosum and H. apenninum subsp. estevei ) and two congeneric widespread taxa (H. cinereum subsp. rotundifolium and H. apenninum subsp. apenninum ) that further belong to two different lineages (subgenera) of Helianthemum . We obtained rather unexpected results contrasting with the theory: (a) The narrow endemic taxa showed higher values of genetic diversity as well as higher average values of pollen production per flower and pollen‐to‐ovule ratio than their widespread relatives; and (b) the two taxa of subg. Helianthemum , with larger corollas, approach herkogamy and higher pollen production than the two taxa of subg. Plectolobum , displayed lower genetic diversity and higher values of inbreeding. Altogether, these results disclose how genetic diversity may be affected simultaneously by a large number of intrinsic and extrinsic factors, especially in Pleistocene glacial refugia in mountains where the spatial context harbors a great ecological heterogeneity. On the other hand, differences in mating system and the significant effect of the substrate profile, both being highly diverse in the genus Helianthemum , in the genetic variability illustrate about the importance of these two factors in the diversification and species differentiation of this paradigmatic genus in the Mediterranean and open the field to formulate and test new hypotheses of local adaptation, trait evolution, and habitat diversification.Secretaría de Estado de Investigación, Desarrollo e Innovación, Grant/Award Number: BES-2015-073314; Ministerio de Economía y Competitividad, Grant/Award Number: CGL2013-45037-P, CGL2014- 52459-P and CGL2017-82465-P; Ministerio de Agricultura, Alimentación y Medio Ambiente, Grant/Award Number: 296/201

Coefficient shifts in geographical ecology: an empirical evaluation of spatial and non-spatial regression

Copyright © 2009 The Authors. Copyright © ECOGRAPHY 2009.A major focus of geographical ecology and macro ecology is to understand the causes of spatially structured ecological patterns. However, achieving this understanding can be complicated when using multiple regressions, because the relative importance of explanatory variables, as measured by regression coefficients, can shift depending on whether spatially explicit or non-spatial modelling is used. However, the extent to which coefficients may shift and why shifts occur are unclear. Here, we analyze the relationship between environmental predictors and the geographical distribution of species richness, body size, range size and abundance in 97 multi-factorial data sets. Our goal was to compare standardized partial regression coefficients of non-spatial ordinary least squares regressions (i.e. models fitted using ordinary least squares without taking autocorrelation into account; “OLS models” hereafter) and eight spatial methods to evaluate the frequency of coefficient shifts and identify characteristics of data that might predict when shifts are likely. We generated three metrics of coefficient shifts and eight characteristics of the data sets as predictors of shifts. Typical of ecological data, spatial autocorrelation in the residuals of OLS models was found in most data sets. The spatial models varied in the extent to which they minimized residual spatial autocorrelation. Patterns of coefficient shifts also varied among methods and datasets, although the magnitudes of shifts tended to be small in all cases. We were unable to identify strong predictors of shifts, including the levels of autocorrelation in either explanatory variables or model residuals. Thus, changes in coefficients between spatial and non-spatial methods depend on the method used and are largely idiosyncratic, making it difficult to predict when or why shifts occur. We conclude that the ecological importance of regression coefficients cannot be evaluated with confidence irrespective of whether spatially explicit modelling is used or not. Researchers may have little choice but to be more explicit about the uncertainty of models and more cautious in their interpretation

Contrasting nuclear-plastidial phylogenetic patterns in the recently diverged Iberian Phlomis crinita and P. lychnitis lineages (Lamiaceae)

Systematic and evolutionary relationships within the diploid Western Mediterranean Phlomis crinita/lychnitis complex remain controversial apparently due to hybridization and introgression. This study examines patterns of sequence variation in the nuclear ribosomal DNA (ITS region) and three non-coding plastid DNA regions (trnH-psbA, trnT-trnL and atpB-rbcL) in this complex in an aim to clarify whether hybridization, introgression or lineage sorting resulting from recent diversification is mainly responsible for poorly understood relationships. Information recovered from nuclear and chloroplast markers was found to be strongly incongruent. Phylogenetic analysis of inferred nuclear ITS ribotypes is consistent with previous morphometric and taxonomic results in distinguishing two sister lineages, P. crinita s.l. and P. lychnitis. In addition, the high number of additive polymorphisms detected in ITS sequences suggests the sharing of ancestral variability and local patterns of gene flow within the complex. In contrast, the pattern of chloroplast haplotype variation is geographic rather than taxonomic, which might be caused by low mutation rates combined with frequent instances of interspecific hybridization. To integrate the apparently discordant plastid and nuclear evidence, we suggest that both lineage sorting and horizontal transfer have been involved. Even though pinpointing cases due to either phenomenon is difficult, the available data provide evidence of two sister lineages where hybridization events can be identified despite the inheritance of ancestral polymorphisms.This study was supported by the Spanish Ministry of Science and Technology (grant BOS2000-0450).Peer reviewe

Implicaciones sistemáticas de una reconstrucción filogenética del género Helianthemum (Cistaceae) basada en datos de GBS

Molecular systematics requires the establishment of a robust phylogenetic framework including extensive geographical and taxonomic sampling. In this work, we proposed systematic changes in the genus&nbsp;Helianthemum&nbsp;based on phylogenetic trees obtained by both maximum likelihood and Bayesian analyses of GBS data. The implications of these phylogenetic results for the systematics of&nbsp;Helianthemum&nbsp;entail the establishment of a new subgenus and novel re-ascriptions of sections and species along with some nomenclatural novelties. The following new combinations are proposed:&nbsp;Helianthemum&nbsp;subg.&nbsp;Eriocarpum&nbsp;(Dunal) Martín-Hernanz, Velayos, Albaladejo &amp; Aparicio;&nbsp;H. oelandicum&nbsp;subsp.&nbsp;conquense&nbsp;(Borja &amp; Rivas Goday ex G.López) Martín-Hernanz, Velayos, Albaladejo &amp; Aparicio;&nbsp;H. nummularium&nbsp;subsp.&nbsp;cantabricum&nbsp;(M.Laínz) Martín-Hernanz, Velayos, Albaladejo &amp; Aparicio;&nbsp;H. nummularium&nbsp;subsp.&nbsp;tinetense&nbsp;(M.Mayor &amp; Fern.Benito) Martín-Hernanz, Velayos, Albaladejo &amp; Aparicio.La sistemática molecular requiere un marco filogenético robusto, que incluya un alto porcentaje de los taxones del grupo de estudio y una amplia representación geográfica. En este trabajo presentamos cambios en el género&nbsp;Helianthemum&nbsp;derivados de reconstrucciones filogenéticas con datos tipo GBS analizados tanto con métodos bayesianos como de máxima verosimilitud. Los resultados filogenéticos apoyan la descripción de un nuevo subgénero dentro de&nbsp;Helianthemum, así como la readscripción de taxones a diferentes niveles taxonómicos y algunas novedades nomenclaturales. Se proponen las siguientes combinaciones:&nbsp;Helianthemum&nbsp;subg.&nbsp;Eriocarpum&nbsp;(Dunal) Martín-Hernanz, Velayos, Albaladejo &amp; Aparicio;&nbsp;H. oelandicum&nbsp;subsp.&nbsp;conquense&nbsp;(Borja &amp; Rivas Goday ex G.López) Martín-Hernanz, Velayos, Albaladejo &amp; Aparicio;&nbsp;H. nummularium&nbsp;subsp.&nbsp;cantabricum&nbsp;(M.Laínz) Martín-Hernanz, Velayos, Albaladejo &amp; Aparicio;&nbsp;H. nummularium&nbsp;subsp.&nbsp;tinetense&nbsp;(M.Mayor &amp; Fern.Benito) Martín-Hernanz, Velayos, Albaladejo &amp; Aparicio

Genetic structure and population differentiation of the Mediterranean pioneer spiny broom Calicotome villosa across the Strait of Gibraltar

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. © 2008 The Linnean Society of London.Peer Reviewe

Networks of spatial genetic variation across species

Spatial patterns of genetic variation provide information central to many ecological, evolutionary, and conservation questions. This spatial variability has traditionally been analyzed through sum- mary 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 pat- terns 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 frag- mented forest mosaic in Southern Spain. Three of the four species show a similar pattern of genetic variation with well-defined mod- ules or groups of patches holding genetically similar populations. These modules can be thought of as the long-sought-after, evo- lutionarily 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 assemblagesPeer reviewe

Contrasting heterozygosity-fitness correlations between populations of a self-compatible shrub in a fragmented landscape

The mechanisms underlying heterozygosity-fitness correlations (HFCs) are subject of intense debates, especially about how important population features such as size or degree of isolation influence HFCs. Here, we report variation in HFCs between Large and Small populations of a self-compatible shrub (Myrtus communis) occurring within an extremely fragmented landscape. In each of the five study populations, we obtained data on both heterozygosity and fitness for 9-12 maternal families (i. e. offspring from the same mother plant). Whereas heterozygosity explained most of the variance (60-86 %) in growth rate of seedling families within Large populations, this relationship was absent within Small populations. Our results suggest that inbreeding may explain the observed HFCs within Large populations, and that different genetic processes (such as genetic drift and/or selection) could have overridden HFCs within Small populations. While it is difficult to draw general conclusions from five populations, we think our results open new research perspectives on how different genetic processes underlie variation in HFCs under different population contexts. Our study also points to a need for further attention on the complex relationships between heterozygosity in self-compatible plants and their progeny in relation to mating system variation. Finally, our results provide interesting new insights into how population genetic diversity is maintained or lost in a highly fragmented landscape. © 2012 Springer Science+Business Media B.V.Peer Reviewe