TY - JOUR A1 - Warren, Ben H. A1 - Simberloff, Daniel A1 - Ricklefs, Robert E. A1 - Aguilee, Robin A1 - Condamine, Fabien L. A1 - Gravel, Dominique A1 - Morlon, Helene A1 - Mouquet, Nicolas A1 - Rosindell, James A1 - Casquet, Juliane A1 - Conti, Elena A1 - Cornuault, Josselin A1 - Maria Fernandez-Palacios, Jose A1 - Hengl, Tomislav A1 - Norder, Sietze J. A1 - Rijsdijk, Kenneth F. A1 - Sanmartin, Isabel A1 - Strasberg, Dominique A1 - Triantis, Kostas A. A1 - Valente, Luis M. A1 - Whittaker, Robert J. A1 - Gillespie, Rosemary G. A1 - Emerson, Brent C. A1 - Thebaud, Christophe T1 - Islands as model systems in ecology and evolution: prospects fifty years after MacArthur-Wilson JF - Ecology letters N2 - The study of islands as model systems has played an important role in the development of evolutionary and ecological theory. The 50th anniversary of MacArthur and Wilson's (December 1963) article, An equilibrium theory of insular zoogeography', was a recent milestone for this theme. Since 1963, island systems have provided new insights into the formation of ecological communities. Here, building on such developments, we highlight prospects for research on islands to improve our understanding of the ecology and evolution of communities in general. Throughout, we emphasise how attributes of islands combine to provide unusual research opportunities, the implications of which stretch far beyond islands. Molecular tools and increasing data acquisition now permit re-assessment of some fundamental issues that interested MacArthur and Wilson. These include the formation of ecological networks, species abundance distributions, and the contribution of evolution to community assembly. We also extend our prospects to other fields of ecology and evolution - understanding ecosystem functioning, speciation and diversification - frequently employing assets of oceanic islands in inferring the geographic area within which evolution has occurred, and potential barriers to gene flow. Although island-based theory is continually being enriched, incorporating non-equilibrium dynamics is identified as a major challenge for the future. KW - Community assembly KW - diversification KW - ecosystem functioning KW - genomics KW - island biogeography KW - islands as model systems KW - speciation Y1 - 2015 U6 - https://doi.org/10.1111/ele.12398 SN - 1461-023X SN - 1461-0248 VL - 18 IS - 2 SP - 200 EP - 217 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Hornych, Ondrej A1 - Ekrt, Libor A1 - Riedel, Felix A1 - Koutecky, Petr A1 - Košnar, Jiří T1 - Asymmetric hybridization in Central European populations of the Dryopteris carthusiana group JF - America Journal of Botany N2 - Premise Hybridization is a key process in plant speciation. Despite its importance, there is no detailed study of hybridization rates in fern populations. A proper estimate of hybridization rates is needed to understand factors regulating hybridization. Methods We studied hybridization in the European Dryopteris carthusiana group, represented by one diploid and two tetraploid species and their hybrids. We sampled 100 individuals per population in 40 mixed populations of the D. carthusiana group across Europe. All plants were identified by measuring genome size (DAPI staining) using flow cytometry. To determine the maternal parentage of hybrids, we sequenced the chloroplast region trnL-trnF of all taxa involved. Results We found hybrids in 85% of populations. Triploid D. xambroseae occurred in every population that included both parent species and is most abundant when the parent species are equally abundant. By contrast, tetraploid D. xdeweveri was rare (15 individuals total) and triploid D. xsarvelae was absent. The parentage of hybrid taxa is asymmetric. Despite expectations from previous studies, tetraploid D. dilatata is the predominant male parent of its triploid hybrid. Conclusions This is a thorough investigation of hybridization rates in natural populations of ferns. Hybridization rates differ greatly even among closely related fern taxa. In contrast to angiosperms, our data suggest that hybridization rates are highest in balanced parent populations and support the notion that some ferns possess very weak barriers to hybridization. Our results from sequencing cpDNA challenge established notions about the correlation of ploidy level and mating tendencies. KW - antheridiogens KW - Dryopteridaceae KW - ferns KW - flow cytometry KW - hybridization rate KW - interspecific hybridization KW - polyploidy KW - reproductive isolation KW - speciation KW - trnL-trnF Y1 - 2019 U6 - https://doi.org/10.1002/ajb2.1369 SN - 0002-9122 SN - 1537-2197 VL - 106 IS - 11 SP - 1477 EP - 1486 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Hennig, Theresa A1 - Stockmann, Madlen A1 - Kühn, Michael T1 - Simulation of diffusive uranium transport and sorption processes in the Opalinus Clay JF - Applied geochemistry : journal of the International Association of Geochemistry and Cosmochemistry N2 - Diffusive transport and sorption processes of uranium in the Swiss Opalinus Clay were investigated as a function of partial pressure of carbon dioxide pCO(2), varying mineralogy in the facies and associated changes in porewater composition. Simulations were conducted in one-dimensional diffusion models on the 100 m-scale for a time of one million years using a bottom-up approach based on mechanistic surface complexation models as well as cation exchange to quantify sorption. Speciation calculations have shown, uranium is mainly present as U(VI) and must therefore be considered as mobile for in-situ conditions. Uranium migrated up to 26 m in both, the sandy and the carbonate-rich facies, whereas in the shaly facies 16 m was the maximum. The main species was the anionic complex CaUO2(CO3)(3)(2-) . Hence, anion exclusion was taken into account and further reduced the migration distances by 30 %. The concentrations of calcium and carbonates reflected by the set pCO(2) determine speciation and activity of uranium and consequently the sorption behaviour. Our simulation results allow for the first time to prioritize on the far-field scale the governing parameters for diffusion and sorption of uranium and hence outline the sensitivity of the system. Sorption processes are controlled in descending priority by the carbonate and calcium concentrations, pH, pe and the clay mineral content. Therefore, the variation in porewater composition resulting from the heterogeneity of the facies in the Opalinus Clay formation needs to be considered in the assessment of uranium migration in the far field of a potential repository. KW - reactive transport KW - facies KW - heterogeneity KW - carbonate KW - PHREEQC KW - Mont Terri KW - speciation Y1 - 2020 U6 - https://doi.org/10.1016/j.apgeochem.2020.104777 SN - 0883-2927 SN - 1872-9134 VL - 123 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Breitkopf, Hendrik A1 - Schlüter, P. M. A1 - Xu, S. A1 - Schiestl, Florian P. A1 - Cozzolino, S. A1 - Scopece, G. T1 - Pollinator shifts between Ophrys sphegodes populations: might adaptation to different pollinators drive population divergence? JF - Journal of evolutionary biology N2 - Local adaptation to different pollinators is considered one of the possible initial stages of ecological speciation as reproductive isolation is a by-product of the divergence in pollination systems. However, pollinator-mediated divergent selection will not necessarily result in complete reproductive isolation, because incipient speciation is often overcome by gene flow. We investigated the potential of pollinator shift in the sexually deceptive orchids Ophrys sphegodes and Ophrys exaltata and compared the levels of floral isolation vs. genetic distance among populations with contrasting predominant pollinators. We analysed floral hydrocarbons as a proxy for floral divergence between populations. Floral adoption of pollinators and their fidelity was tested using pollinator choice experiments. Interpopulation gene flow and population differentiation levels were estimated using AFLP markers. The Tyrrhenian O.sphegodes population preferentially attracted the pollinator bee Andrena bimaculata, whereas the Adriatic O.sphegodes population exclusively attracted A.nigroaenea. Significant differences in scent component proportions were identified in O.sphegodes populations that attracted different preferred pollinators. High interpopulation gene flow was detected, but populations were genetically structured at species level. The high interpopulation gene flow levels independent of preferred pollinators suggest that local adaptation to different pollinators has not (yet) generated detectable genome-wide separation. Alternatively, despite extensive gene flow, few genes underlying floral isolation remain differentiated as a consequence of divergent selection. Different pollination ecotypes in O.sphegodes might represent a local selective response imposed by temporal variation in a geographical mosaic of pollinators as a consequence of the frequent disturbance regimes typical of Ophrys habitats. KW - adaptation KW - ecotypes KW - floral scent KW - gene flow KW - Ophrys KW - orchids KW - pollinator shift KW - sexual deception KW - speciation Y1 - 2013 U6 - https://doi.org/10.1111/jeb.12216 SN - 1010-061X SN - 1420-9101 VL - 26 IS - 10 SP - 2197 EP - 2208 PB - Wiley-Blackwell CY - Hoboken ER -