Proceedings of the Amurga International Conferences on Island Biodiversity 2011
Caujapé-Castells J, Nieto-Feliner G, Fernández-Palacios JM (eds.)
Under the overarching idea that preserving biodiversity is only possible through its scientific understanding, the Fundación Canaria Amurga Maspalomas and the Jardín Botánico Canario “Viera y Clavijo-Unidad Asociada CSIC of the Cabildo Insular de Gran Canaria organised on March 2011 the first edition of the “Fundación Amurga International Conferences on Island Biodiversity”. The objective of this unprecedented meeting was to bring together some of the internationally most renowned researchers from around the world to share existing and developing knowledge on the evolution, diversity and conservation of the lush and unique (but also extremely fragile, and increasingly threatened) biota of oceanic islands. As a consequence of the keen acceptance to attend of most selected scientists, a wide number of diverse topics was covered, ranging from classical and molecular taxonomy to reproductive biology, phylogenetic and genetic diversity, phylogeny, biogeography, cytogenetics, and the applications of all these fields to understand evolution on islands, or to design informed conservation and management strategies. Sharing diverse worldviews of the past, present and future of insular plant biodiversity throughout a week inevitably triggered new and productive multi-disciplinary interaction, so we believe that the meeting’s purpose was largely overachieved thanks to the general enthusiasm that it created. The objective of this proceedings volume is simply to gather the ideas that were discussed during that week just as they were transmitted by the speakers, so we explicitly discouraged the authors from attempting to update the contents of the discussions in 2011. For similar reasons (and because of multiple heterogeneous commitments in our respective institutions), we have not reviewed the idiomatic contents of the contributions. As the scientific editors of this volume, our mission has restrained to make a consistent whole out of all the submitted texts, to oversee their scientific contents and, in some cases, to suggest a minimum number of formal changes. In all probability, this book will not have a high SCI impact factor, so that the fact that most such distinguished scientists made an effort to submit their full papers in time is perhaps another indicator of the meeting’s success. The specialist reader will notice that some contributions are slightly outdated, because their authors have already published refined versions of these ideas, in some cases thanks to the open and friendly discussions that all the attendees (speakers or not) furnished. For the nonspecialists, this volume is a rare opportunity to catch up with ongoing progresses on the investigation of oceanic island floras, in some cases hand in hand with top-notch researchers in different fields of expertise. It is thus with sheer pleasure that we thank the support of the Fundación Canaria Amurga Maspalomas and the Cabildo Insular de Gran Canaria in the organisation of this meeting. We hope that these two institutions from Gran Canaria continue showing that Macaronesia is today a remarkable hotspot of ideas about the evolution of life on islands, and a land of opportunity for new research endeavors.
Get pdf
Population genetics in the conservation of the Azorean shrub Viburnum treleasei Gand.
Moura M, Silva L, Caujapé-Castells J
Plant Systematics and Evolution 2013 (in press)
We assess population genetic structure and variability in the endangered Azorean endemic Viburnum treleasei Gand., an evergreen shrub or small tree, occurring in eight out of nine islands of the archipelago. We combine RAPD and ISSR markers in eight populations and four islands covering the three subgroups of islands that compose the archipelago, and one population of V. tinus from the Portuguese mainland. Most of the genetic variability was found within populations, which is in accordance with the bi-parental reproductive strategy favoured by the taxon. Gene flow estimations for the combined RAPD and ISSR markers suggest that the main cause for population variability between the studied populations is genetic drift. In accordance with the genetic structure indicators obtained, conservation measures should consider that translocation of individuals between islands must be avoided. In specific cases, the analysed populations may require the implementation of augmentation strategies due to their depleted state. With this study, a genetic background is now available to better define conservation measures for the taxon.
Get pdf
A local dormancy cline is related to the seed maturation environment, population genetic composition and climate
Fernández-Pascual E, Jiménez-Alfaro B, Caujapé-Castells J, Jaén-Molina R, Díaz TE
Annals of Botany 2013 (in press)
• Background and Aims: Seed dormancy varies within species in response to climate, both in the long term (through ecotypes or clines) and in the short term (through the influence of the seed maturation environment). Disentangling both processes is crucial to understand plant adaptation to environmental changes. Here we investigated the local patterns of seed dormancy in a narrow endemic species, Centaurium somedanum, to determine the influence of the seed maturation environment, population genetic composition and climate.
• Methods: We performed laboratory germination experiments to measure dormancy in (1) seeds collected from different wild populations along a local altitudinal gradient and (2) seeds of a subsequent generation produced in a common garden. We characterized the genetic composition of the original populations using Inter-Simple Sequence Repeat PCR and PCoA, and analyzed its correlation to the dormancy patterns of both generations. We also modelled the effect of the local climate on dormancy.
• Key Results We found an altitudinal dormancy cline in the wild populations, which was maintained by the plants grown in the common garden. However, seeds from the common garden responded better to stratification, and their release from dormancy was more intense. The patterns of dormancy variation were correlated to genetic composition; while lower temperature and summer precipitation at the population sites predicted higher dormancy in the seeds of both generations.
• Conclusions: The dormancy cline in C. somedanum is related to a local climatic gradient and also corresponds with genetic differentiation among populations. This cline is further affected by the weather conditions during seed maturation, which influence the receptiveness to dormancy-breaking factors. These results show that dormancy is influenced both by long and short term climatic variation. Such processes at such a reduced spatial scale highlight the potential of plants to adapt to fast environmental changes.
Get pdf
Effects of clonality on the genetic variability of endangered rare, insular species: the case of Ruta microcarpa from the Canary Islands.
Meloni M, Reid A, Caujapé-Castells J, Marrero Á, Fernández-Palacios JM, Mesa-Coello R, Conti E
Ecology and Evolution (in press, DOI: 10.1002/ece3.571).
Many plant species combine sexual and clonal reproduction. Clonal propagation has ecological costs mainly related to inbreeding depression and pollen discounting; at the same time, species able to reproduce clonally have ecological and evolutionary advantages being able to persist when conditions are not favorable for sexual reproduction. The presence of clonality has profound consequences on the genetic structure of populations, especially when it represents the predominant reproductive strategy in a population. Theoretical studies suggest that high rate of clonal propagation should increase the effective number of alleles and heterozygosity in a population, while an opposite effect is expected on genetic differentiation among populations and on genotypic diversity. In this study, we ask how clonal propagation affects the genetic diversity of rare insular species, which are often characterized by low levels of genetic diversity, hence at risk of extinction. We used eight polymorphic microsatellite markers to study the genetic structure of the critically endangered insular endemic Ruta microcarpa. We found that clonality appears to positively affect the genetic diversity of R. microcarpa by increasing allelic diversity, polymorphism, and heterozygosity. Moreover, clonal propagation seems to be a more successful reproductive strategy in small, isolated population subjected to environmental stress. Our results suggest that clonal propagation may benefit rare species. However, the advantage of clonal growth may be only short-lived for prolonged clonal growth could ultimately lead to monoclonal populations. Some degree of sexual reproduction may be needed in a predominantly clonal species to ensure long-term viability.
Bird-pollinated Macaronesian Lotus (Leguminosae) evolved within a group of entomophilous ancestors with post-anthesis flower colour change
Ojeda D, Santos-Guerra A, Oliva-Tejera F, Valido A, Xue X, Marrero Á, Caujapé-Castells J, Cronk Q
Perspectives in Plant Ecology, Evolution and Systematics 2013 (in press)
We analysed the evolution of red/orange flowers in four putatively bird-pollinated species of Macaronesian Lotus, with the aim of investigating whether this floral trait evolved from a similar trait found in some entomophilous Lotus species, namely the ability to modify flower colour to red after anthesis. First, we mapped the ability to modify flower colour in this group on a well-resolved and densely sampled phylogenetic tree of the Macaronesian Lotus. Secondly, we determined differences in light reflectance and pigment composition between petals of (1) prechange and postchange flowers in bee-pollinated species, and (2) between bee and putatively bird-pollinated species. Post-anthesis flower colour change evolved three times within Macaronesian Lotus, and putatively bird-pollinated species evolved within a clade with this ability to change flower colour to red after anthesis. The evolutionary transition to red/orange flowers in the putatively bird-pollinated species involved biochemical changes similar to those of the developmental transition to red postchange flowers. In both cases there are changes in the composition of flavonols and anthocyanidins within the same metabolic pathways, especially in the cyanidin branch of pigment production, but not the activation or inactivation of additional branches of this pathway. Post-anthesis colour change in Lotus, from yellow to red, is thought to be an adaptation to reduce bee visits to already pollinated flowers. Our results are consistent with the hypothesis that constitutive red coloration for bird-pollination evolved from facultative red flower colour change in Lotus. As red post-anthesis coloration is widespread in plants, this may possibly represent a widespread exaptive mechanism for the evolution of bird pollination.
Get pdf
Phylogenetic analysis of ITS2 sequences suggests the taxonomic re-structuring of Dunaliella viridis (Chlorophyceae, Dunaliellales).
Assunção P, Jaén-Molina R, Caujapé-Castells J, Wolf M, Buchheim MA, de la Jara A, Carmona L, Freijanes K, Mendoza H
Phycological Research (in press).
We analyzed the ITS2 primary and secondary structure [including Compensatory Base Changes (CBCs)] of new field D. viridis strains and compared this taxon with other Dunaliella sequences available from the ITS2 database to circumscribe its taxonomic position. The ITS2 primary and secondary structure analysis positioned the majority of D. viridis strains in four main different clades, revealing great heterogeneity. The detection of at least one CBC between the majority of D. viridis strains of each viridis-clade strongly suggests that they could correspond to different biological species. Unexpectedly, while D. viridis var. euchlora (CCAP19/21) was positioned within the subgenus Dunaliella, D. viridis var. palmelloides (CCAP11/34) was positioned clearly outside this subgenus, suggesting that it may not be a Dunaliella. Furthermore, the detection of at least three compensatory base changes (CBCs) between D. viridis var. palmelloides (CCAP11/34) and the other strains analyzed confirm that this strain is a different species. For these reasons we propose the provisional re-naming of these strains to Dunaliella palmelloides and Dunaliella euchlora incertae sedis. Therefore, the ITS2 primary and secondary structure data suggest a taxonomic re-structuring of D. viridis.
Get pdf
A review of the allozyme dataset for the Canarian endemic flora: causes of the high genetic diversity levels, implications for conservation
Pérez de Paz J, Caujapé-Castells J
Annals of Botany 2013 (in press)
• Background and Aims: We update the allozyme and reproductive datasets for the Canarian flora to (i) assess how the present levels and structuring of genetic variation have been influenced by the abiotic island traits and by phylogenetically determined biotic traits of the corresponding taxa; and (ii) suggest conservation guidelines.
• Methods: We conduct (i) Kruskal-Wallis tests to assess the relationships of 27 variables with genetic diversity (estimated by A, P, Ho and He) and structuring (GST) of 123 taxa representing 309 populations and 16 families (see http://www.demiurge-project.org/matrix_digests/D-ALLOZ-15); and (ii) multiple linear regression analyses (MLRA) to determine the relative influence of the less correlated significant abiotic and biotic factors on the genetic diversity levels.
• Conclusions: The interactions between biotic features of the colonizing taxa and the abiotic island features drive plant diversification in the Canarian flora. However, the lower weight of closeness to the mainland than of (respectively) high basic chromosome number, partial or total self-incompatibility and polyploidy in the MLRA indicates substantial phylogenetic constraint; the importance of a high chromosome number is feasibly due to the generation of a larger number of linkage groups, which increase gametic and genotypic diversity. Genetic structure is also more influenced by biotic factors (respectively long-range seed dispersal, basic chromosome number, and partial or total self-incompatibility) than by distance to the mainland. Conservation-wise, genetic structure estimates (FST/GST) only reflect endangerment under intensive population sampling designs, and neutral genetic variation levels do not directly relate either to threat status or to small population sizes. We emphasize habitat protection, but our results suggest the urgent implementation of elementary reproductive studies in all cases, and of ex situ conservation measures for the most endangered taxa, even without prior studies. In non-endangered endemics, multi-disciplinary research is needed before suggesting case-specific conservation strategies. Also of utmost importance, the molecular information relevant for conservation should be conserved in a standardized format to facilitate further insight.
Polyploidy and microsatellite variation in the relict tree Prunus lusitanica L.: how effective are refugia in preserving genotypic diversity of clonal taxa?
García-Verdugo C, Calleja JA, Vargas P, Silva L, Moreira O, Pulido F
Molecular Ecology 2013 (in press, doi: 10.1111/mec.12194)
Refugia are expected to preserve genetic variation of relict taxa, especially in polyploids, because high gene dosages could prevent genetic erosion in small isolated populations. However, other attributes linked to polyploidy, such as asexual reproduction, may strongly limit the levels of genetic variability in relict populations. Here, ploidy levels and patterns of genetic variation at nuclear microsatellite loci were analysed in Prunus lusitanica, a polyploid species with clonal reproduction that is considered a paradigmatic example of a Tertiary relict. Sampling in this study considered a total of 20 populations of three subspecies: mainland lusitanica (Iberian Peninsula and Morocco), and island azorica (Azores) and hixa (Canary Islands and Madeira). Flow cytometry results supported an octoploid genome for lusitanica and hixa, whereas a 16-ploid level was inferred for azorica. Fixed heterozygosity of a few allele variants at most microsatellite loci resulted in levels of allelic diversity much lower than those expected for a high-order polyploid. Islands as a whole did not contain higher levels of genetic variation (allelic or genotypic) than mainland refuges, but island populations displayed more private alleles and higher genotypic diversity in old volcanic areas. Patterns of microsatellite variation were compatible with the occurrence of clonal individuals in all but two island populations, and the incidence of clonality within populations negatively correlated with the estimated timing of colonization. Our results also suggest that gene flow has been very rare among populations, and thus population growth following founder events was apparently mediated by clonality rather than seed recruitment, especially in mainland areas. This study extends to clonal taxa the idea of oceanic islands as important refugia for biodiversity, since the conditions for generation and maintenance of clonal diversity (i.e. occasional events of sexual reproduction, mutation and/or seed immigration) appear to have been more frequent in these enclaves than in mainland areas.
Transformer-4 version 2.0.1, a free multi-platform software to quickly reformat genotype matrices of any marker type, and archive them in the Demiurge information system
Caujapé-Castells J, Sabbagh I, Castellano JJ, Ramos R, Henríquez V, Quintana FM, Medina DA, Toledo J, Ramírez F, Rodríguez JF
Molecular Ecology Resources 2013 (doi: 10.1111/1755-0998.12084)
Transformer-4 version 2.0.1 (T4) is a multi-platform freeware programmed in JAVA that can transform a genotype matrix in Excel or XML format into the input formats of one or several of the most commonly used population genetic software, for any possible combination of the populations that the matrix contains. T4 also allows the users to (i) draw allozyme gel interpretations for any number of diploid individuals, and then generate a genotype matrix ready to be used by T4; and (ii) produce basic reports about the data in the matrices. Furthermore, T4 is the only way to optionally submit ‘genetic diversity digests’ for publication in the Demiurge online information system (http://www.demiurge-project.org). Each such digest undergoes peer-review, and it consists of a geo-referenced data matrix in the tfm4 format plus any ancillary document or hyperlink that the digest authors see fit to include. The complementarity between T4 and Demiurge facilitates a free, safe, permanent, and standardized data archival and analysis system for researchers, and may also be a convenient resource for scientific journals, public administrations, or higher educators. T4 and its converters are freely available (at, respectively, http://www.demiurge-project.org/download_t4 and http://www.demiurge-project.org/converterstore) upon registration in the Demiurge information system (http://demiurge-project.org/register). Users have to click on the link provided on an account validation email, and accept Demiurge’s terms of use (see http://www.demiurge-project.org/termsofuse). A thorough user’s guide is available within T4. A 3-min promotional video about T4 and Demiurge can be seen at http://vimeo.com/29828406.