1
|
Nakanishi A, Goto S, Sumiyoshi C, Isagi Y. Directional seed and pollen dispersal and their separate effects on anisotropy of fine-scale spatial genetic structure among seedlings in a dioecious, wind-pollinated, and wind-dispersed tree species, Cercidiphyllum japonicum. Ecol Evol 2021; 11:7754-7767. [PMID: 34188849 PMCID: PMC8216893 DOI: 10.1002/ece3.7609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 04/05/2021] [Accepted: 04/06/2021] [Indexed: 11/18/2022] Open
Abstract
Prevailing directions of seed and pollen dispersal may induce anisotropy of the fine-scale spatial genetic structure (FSGS), particularly in wind-dispersed and wind-pollinated species. To examine the separate effects of directional seed and pollen dispersal on FSGS, we conducted a population genetics study for a dioecious, wind-pollinated, and wind-dispersed tree species, Cercidiphyllum japonicum Sieb. et Zucc, based on genotypes at five microsatellite loci of 281 adults of a population distributed over a ca. 80 ha along a stream and 755 current-year seedlings. A neighborhood model approach with exponential-power-von Mises functions indicated shorter seed dispersal (mean = 69.1 m) and much longer pollen dispersal (mean = 870.6 m), effects of dispersal directions on the frequencies of seed and pollen dispersal, and the directions with most frequent seed and pollen dispersal (prevailing directions). Furthermore, the distance of effective seed dispersal within the population was estimated to depend on the dispersal direction and be longest at the direction near the prevailing direction. Therefore, patterns of seed and pollen dispersal may be affected by effective wind directions during the period of respective dispersals. Isotropic FSGS and spatial sibling structure analyses indicated a significant FSGS among the seedlings generated by the limited seed dispersal, but anisotropic analysis for the seedlings indicated that the strength of the FSGS varied with directions between individuals and was weakest at a direction near the directions of the most frequent and longest seed dispersal but far from the prevailing direction of pollen dispersal. These results suggest that frequent and long-distance seed dispersal around the prevailing direction weakens the FSGS around the prevailing direction. Therefore, spatially limited but directional seed dispersal would determine the existence and direction of FSGS among the seedlings.
Collapse
Affiliation(s)
- Atsushi Nakanishi
- Hokkaido Research Center, Forestry and Forest Products Research InstituteForest Research and Management OrganizationSapporoJapan
| | - Susumu Goto
- Education and Research CenterThe University of Tokyo ForestsGraduate School of Agricultural and Life SciencesThe University of TokyoTokyoJapan
| | - Chikako Sumiyoshi
- Faculty of Integrated Arts and SciencesHiroshima UniversityHigashi‐HiroshimaJapan
- Present address:
DeepL GmbHCologneGermany
| | - Yuji Isagi
- Faculty of Integrated Arts and SciencesHiroshima UniversityHigashi‐HiroshimaJapan
- Present address:
Graduate School of AgricultureKyoto UniversityKyotoJapan
| |
Collapse
|
2
|
Global wind patterns shape genetic differentiation, asymmetric gene flow, and genetic diversity in trees. Proc Natl Acad Sci U S A 2021; 118:2017317118. [PMID: 33875589 DOI: 10.1073/pnas.2017317118] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Wind disperses the pollen and seeds of many plants, but little is known about whether and how it shapes large-scale landscape genetic patterns. We address this question by a synthesis and reanalysis of genetic data from more than 1,900 populations of 97 tree and shrub species around the world, using a newly developed framework for modeling long-term landscape connectivity by wind currents. We show that wind shapes three independent aspects of landscape genetics in plants with wind pollination or seed dispersal: populations linked by stronger winds are more genetically similar, populations linked by directionally imbalanced winds exhibit asymmetric gene flow ratios, and downwind populations have higher genetic diversity. For each of these distinct hypotheses, partial correlations between the respective wind and genetic metrics (controlling for distance and climate) are positive for a significant majority of wind-dispersed or wind-pollinated genetic data sets and increase significantly across functional groups expected to be increasingly influenced by wind. Together, these results indicate that the geography of both wind strength and wind direction play important roles in shaping large-scale genetic patterns across the world's forests. These findings have implications for various aspects of basic plant ecology and evolution, as well as the response of biodiversity to future global change.
Collapse
|
3
|
Tonnabel J, Klein EK, Ronce O, Oddou-Muratorio S, Rousset F, Olivieri I, Courtiol A, Mignot A. Sex-specific spatial variation in fitness in the highly dimorphic Leucadendron rubrum. Mol Ecol 2021; 30:1721-1735. [PMID: 33559274 DOI: 10.1111/mec.15833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 01/27/2021] [Accepted: 01/29/2021] [Indexed: 12/16/2022]
Abstract
Sexual dimorphism in plants may emerge as a result of sex-specific selection on traits enhancing access to nutritive resources and/or to sexual partners. Here we investigated sex-specific differences in selection of sexually dimorphic traits and in the spatial distribution of effective fecundity (our fitness proxy) in a highly dimorphic dioecious wind-pollinated shrub, Leucadendron rubrum. In particular, we tested for the effect of density on male and female effective fecundity. We used spatial and genotypic data of parent and offspring cohorts to jointly estimate individual male and female effective fecundity on the one hand and pollen and seed dispersal kernels on the other hand. This methodology was adapted to the case of dioecious species. Explicitly modelling dispersal avoids the confounding effects of heterogeneous spatial distribution of mates and sampled seedlings on the estimation of effective fecundity. We also estimated selection gradients on plant traits while modelling sex-specific spatial autocorrelation in fecundity. Males exhibited spatial autocorrelation in effective fecundity at a smaller scale than females. A higher local density of plants was associated with lower effective fecundity in males but was not related to female effective fecundity. These results suggest sex-specific sensitivities to environmental heterogeneity in L. rubrum. Despite these sexual differences, we found directional selection for wider canopies and smaller leaves in both sexes, and no sexually antagonistic selection on strongly dimorphic traits in L. rubrum. Many empirical studies in animals similarly failed to detect sexually antagonistic selection in species expressing strong sexual dimorphism, and we discuss reasons explaining this common pattern.
Collapse
Affiliation(s)
- Jeanne Tonnabel
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France.,Department of Ecology and Evolution, Le Biophore, UNIL-SORGE, University of Lausanne, Lausanne, Switzerland
| | | | - Ophélie Ronce
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France.,CNRS, Biodiversity Research Center, University of British Columbia, Vancouver, Canada
| | | | - François Rousset
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Isabelle Olivieri
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Alexandre Courtiol
- Department of Evolutionary Genetics, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Agnès Mignot
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| |
Collapse
|
4
|
Geremew A, Woldemariam MG, Kefalew A, Stiers I, Triest L. Isotropic and anisotropic processes influence fine-scale spatial genetic structure of a keystone tropical plant. AOB PLANTS 2018; 10:plx076. [PMID: 29383234 PMCID: PMC5777495 DOI: 10.1093/aobpla/plx076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 01/02/2018] [Indexed: 06/07/2023]
Abstract
Limited seed or pollen dispersal enhances spatial genetic relatedness between individuals (fine-scale spatial genetic structure, FSGS), which usually decreases as a function of physical distance. However, such isotropic pattern of FSGS may not always occur when spatially asymmetric processes, for instance, wind direction during dispersal, are considered in wind-pollinated and -dispersed plants. This study assessed the pattern of FSGS in the keystone tropical wetland plant Cyperus papyrus (papyrus) as a function of these isotropic and anisotropic processes. We tested the hypothesis that the FSGS would be influenced by predominant wind direction during pollen and seed dispersal, as well as by the physical distance between individuals. We genotyped a total of 510 adults and 407 juveniles from three papyrus swamps (Ethiopia) using 15 microsatellite markers. In addition, the contemporary directional dispersal by wind was evaluated by seed release-recapture experiments and complemented with parentage analysis. Adults and juveniles differed in the strength of isotropic FSGS ranging from 0.09 to 0.13 and 0.12 to 0.16, respectively, and this suggests variation in dispersal distance. Anisotropic FSGS was found to be a function of asymmetric wind direction during dispersal/pollination that varied between sites. Historical gene dispersal distance was astoundingly low (<4 m), possibly due to localized seed rain. According to our contemporary dispersal estimates, mean pollen dispersal distances were longer than those of seed dispersal (101 and <55 m, respectively). More than two-thirds of seeds and half of pollen grains were locally dispersed (≤80 m). The difference in historical and contemporary dispersal distance probably resulted from the asymmetric wind direction due to change in vegetation cover in the surrounding matrix. We further concluded that, in addition to wind direction, post-dispersal processes could influence gene dispersal distance inferred from the FSGS.
Collapse
Affiliation(s)
- Addisie Geremew
- Department of Biology, Vrije Universiteit Brussel (VUB), Pleinlaan,Brussels, Belgium
| | | | - Alemayehu Kefalew
- Department of Plant Biology and Biodiversity Management, College of Natural Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Iris Stiers
- Department of Biology, Vrije Universiteit Brussel (VUB), Pleinlaan,Brussels, Belgium
| | - Ludwig Triest
- Department of Biology, Vrije Universiteit Brussel (VUB), Pleinlaan,Brussels, Belgium
| |
Collapse
|
5
|
Rinnan DS. The dispersal success and persistence of populations with asymmetric dispersal. THEOR ECOL-NETH 2017. [DOI: 10.1007/s12080-017-0348-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
6
|
Inter-annual maintenance of the fine-scale genetic structure in a biennial plant. Sci Rep 2016; 6:37712. [PMID: 27883087 PMCID: PMC5121606 DOI: 10.1038/srep37712] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/02/2016] [Indexed: 11/13/2022] Open
Abstract
Within plant populations, space-restricted gene movement, together with environmental heterogeneity, can result in a spatial variation in gene frequencies. In biennial plants, inter-annual flowering migrants can homogenize gene frequencies between consecutive cohorts. However, the actual impact of these migrants on spatial genetic variation remains unexplored. Here, we used 10 nuclear microsatellite and one plastid genetic marker to characterize the spatial genetic structure within two consecutive cohorts in a population of the biennial plant Erysimum mediohispanicum (Brassicaceae). We explored the maintenance of this structure between consecutive flowering cohorts at different levels of complexity, and investigated landscape effects on gene flow. We found that cohorts were not genetically differentiated and showed a spatial genetic structure defined by a negative genetic-spatial correlation at fine scale that varied in intensity with compass directions. This spatial genetic structure was maintained when comparing plants from different cohorts. Additionally, genotypes were consistently associated with environmental factors such as light availability and soil composition, but to a lesser extent compared with the spatial autocorrelation. We conclude that inter-annual migrants, in combination with limited seed dispersal and environmental heterogeneity, play a major role in shaping and maintaining the spatial genetic structure among cohorts in this biennial plant.
Collapse
|
7
|
Miller MD. The Modifiable Conceptual Unit Problem demonstrated using pollen and seed dispersal. Glob Ecol Conserv 2016. [DOI: 10.1016/j.gecco.2016.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
8
|
Impact of asymmetric male and female gamete dispersal on allelic diversity and spatial genetic structure in valley oak (Quercus lobata Née). Evol Ecol 2015. [DOI: 10.1007/s10682-015-9769-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
9
|
Roumet M, Cayre A, Latreille M, Muller MH. Quantifying temporal isolation: a modelling approach assessing the effect of flowering time differences on crop-to-weed pollen flow in sunflower. Evol Appl 2015; 8:64-74. [PMID: 25667603 PMCID: PMC4310582 DOI: 10.1111/eva.12222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 09/15/2014] [Indexed: 01/08/2023] Open
Abstract
Flowering time divergence can be a crucial component of reproductive isolation between sympatric populations, but few studies have quantified its actual contribution to the reduction of gene flow. In this study, we aimed at estimating pollen-mediated gene flow between cultivated sunflower and a weedy conspecific sunflower population growing in the same field and at quantifying, how it is affected by the weeds' flowering time. For that purpose, we extended an existing mating model by including a temporal distance (i.e. flowering time difference between potential parents) effect on mating probabilities. Using phenological and genotypic data gathered on the crop and on a sample of the weedy population and its offspring, we estimated an average hybridization rate of approximately 10%. This rate varied strongly from 30% on average for weeds flowering at the crop flowering peak to 0% when the crop finished flowering and was affected by the local density of weeds. Our result also suggested the occurrence of other factors limiting crop-to-weed gene flow. This level of gene flow and its dependence on flowering time might influence the evolutionary fate of weedy sunflower populations sympatric to their crop relative.
Collapse
Affiliation(s)
- Marie Roumet
- INRA, UMR 1334, Amélioration Génétique et Adaptation des Plantes méditerranéennes et tropicales (AGAP) Montpellier Cedex 1, France ; ETH Zurich, Institute of Integrative Biology (IBZ) Zurich, Switzerland
| | - Adeline Cayre
- INRA, UMR 1334, Amélioration Génétique et Adaptation des Plantes méditerranéennes et tropicales (AGAP) Montpellier Cedex 1, France
| | - Muriel Latreille
- INRA, UMR 1334, Amélioration Génétique et Adaptation des Plantes méditerranéennes et tropicales (AGAP) Montpellier Cedex 1, France
| | - Marie-Hélène Muller
- INRA, UMR 1334, Amélioration Génétique et Adaptation des Plantes méditerranéennes et tropicales (AGAP) Montpellier Cedex 1, France
| |
Collapse
|
10
|
Goodsman DW, Cooke B, Coltman DW, Lewis MA. The genetic signature of rapid range expansions: How dispersal, growth and invasion speed impact heterozygosity and allele surfing. Theor Popul Biol 2014; 98:1-10. [PMID: 25201435 DOI: 10.1016/j.tpb.2014.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 08/21/2014] [Accepted: 08/25/2014] [Indexed: 11/19/2022]
Abstract
As researchers collect spatiotemporal population and genetic data in tandem, models that connect demography and dispersal to genetics are increasingly relevant. The dominant spatiotemporal model of invasion genetics is the stepping-stone model which represents a gradual range expansion in which individuals jump to uncolonized locations one step at a time. However, many range expansions occur quickly as individuals disperse far from currently colonized regions. For these types of expansion, stepping-stone models are inappropriate. To more accurately reflect wider dispersal in many organisms, we created kernel-based models of invasion genetics based on integrodifference equations. Classic theory relating to integrodifference equations suggests that the speed of range expansions is a function of population growth and dispersal. In our simulations, populations that expanded at the same speed but with spread rates driven by dispersal retained more heterozygosity along axes of expansion than range expansions with rates of spread that were driven primarily by population growth. To investigate surfing we introduced mutant alleles in wave fronts of simulated range expansions. In our models based on random mating, surfing alleles remained at relatively low frequencies and surfed less often compared to previous results based on stepping-stone simulations with asexual reproduction.
Collapse
Affiliation(s)
- Devin W Goodsman
- Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, Alberta, Canada T6G 2E9.
| | - Barry Cooke
- Canadian Forest Service, Northern Forestry Centre, 5320 122 Street Northwest, Edmonton, Alberta, Canada T6H 3S5.
| | - David W Coltman
- Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, Alberta, Canada T6G 2E9.
| | - Mark A Lewis
- Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, Alberta, Canada T6G 2E9; Mathematical and Statistical Sciences, 632 CAB, University of Alberta, Edmonton, Alberta, Canada T6G 2G1.
| |
Collapse
|
11
|
Rhodes MK, Fant JB, Skogen KA. Local topography shapes fine-scale spatial genetic structure in the Arkansas Valley evening primrose, Oenothera harringtonii (Onagraceae). J Hered 2014; 105:806-15. [PMID: 25189774 DOI: 10.1093/jhered/esu051] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Identifying factors that shape the spatial distribution of genetic variation is crucial to understanding many population- and landscape-level processes. In this study, we explore fine-scale spatial genetic structure in Oenothera harringtonii (Onagraceae), an insect-pollinated, gravity-dispersed herb endemic to the grasslands of south-central and southeastern Colorado, USA. We genotyped 315 individuals with 11 microsatellite markers and utilized a combination of spatial autocorrelation analyses and landscape genetic models to relate life history traits and landscape features to dispersal processes. Spatial genetic structure was consistent with theoretical expectations of isolation by distance, but this pattern was weak (Sp = 0.00374). Anisotropic analyses indicated that spatial genetic structure was markedly directional, in this case consistent with increased dispersal along prominent slopes. Landscape genetic models subsequently confirmed that spatial genetic variation was significantly influenced by local topographic heterogeneity, specifically that geographic distance, elevation and aspect were important predictors of spatial genetic structure. Among these variables, geographic distance was ~68% more important than elevation in describing spatial genetic variation, and elevation was ~42% more important than aspect after removing the effect of geographic distance. From these results, we infer a mechanism of hydrochorous seed dispersal along major drainages aided by seasonal monsoon rains. Our findings suggest that landscape features may shape microevolutionary processes at much finer spatial scales than typically considered, and stress the importance of considering how particular dispersal vectors are influenced by their environmental context.
Collapse
Affiliation(s)
- Matthew K Rhodes
- From the Division of Plant Science and Conservation, Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL 60022, USA (Rhodes, Fant, and Skogen); and the Program in Plant Biology and Conservation, Northwestern University, 2205 Tech Drive, O.T. Hogan Hall, Room 2-144, Evanston, IL 60208, USA (Rhodes).
| | - Jeremie B Fant
- From the Division of Plant Science and Conservation, Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL 60022, USA (Rhodes, Fant, and Skogen); and the Program in Plant Biology and Conservation, Northwestern University, 2205 Tech Drive, O.T. Hogan Hall, Room 2-144, Evanston, IL 60208, USA (Rhodes)
| | - Krissa A Skogen
- From the Division of Plant Science and Conservation, Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL 60022, USA (Rhodes, Fant, and Skogen); and the Program in Plant Biology and Conservation, Northwestern University, 2205 Tech Drive, O.T. Hogan Hall, Room 2-144, Evanston, IL 60208, USA (Rhodes)
| |
Collapse
|
12
|
Saro I, Robledo-Arnuncio JJ, González-Pérez MA, Sosa PA. Patterns of pollen dispersal in a small population of the Canarian endemic palm (Phoenix canariensis). Heredity (Edinb) 2014; 113:215-23. [PMID: 24619186 DOI: 10.1038/hdy.2014.16] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 12/20/2013] [Accepted: 01/23/2014] [Indexed: 11/09/2022] Open
Abstract
The genetic diversity of small populations is greatly influenced by local dispersal patterns and genetic connectivity among populations, with pollen dispersal being the major component of gene flow in many plants species. Patterns of pollen dispersal, mating system parameters and spatial genetic structure were investigated in a small isolated population of the emblematic palm Phoenix canariensis in Gran Canaria island (Canary Islands). All adult palms present in the study population (n=182), as well as 616 seeds collected from 22 female palms, were mapped and genotyped at 8 microsatellite loci. Mating system analysis revealed an average of 5.8 effective pollen donors (Nep) per female. There was strong variation in correlated paternity rates across maternal progenies (ranging from null to 0.9) that could not be explained by the location and density of local males around focal females. Paternity analysis revealed a mean effective pollen dispersal distance of ∼71 m, with ∼70% of effective pollen originating from a distance of <75 m, and 90% from <200 m. A spatially explicit mating model indicated a leptokurtic pollen dispersal kernel, significant pollen immigration (12%) from external palm groves and a directional pollen dispersal pattern that seems consistent with local altitudinal air movement. No evidence of inbreeding or genetic diversity erosion was found, but spatial genetic structure was detected in the small palm population. Overall, the results suggest substantial pollen dispersal over the studied population, genetic connectivity among different palm groves and some resilience to neutral genetic erosion and subsequently to fragmentation.
Collapse
Affiliation(s)
- I Saro
- Grupo de Biogeografía, Conservación y Territorio, Universidad de Las Palmas de Gran Canaria (ULPGC), Las Palmas de Gran Canaria, Gran Canaria, Canary Islands, Spain
| | - J J Robledo-Arnuncio
- Department of Forest Ecology and Genetics, Forest Research Center (CIFOR), INIA, Madrid, Spain
| | - M A González-Pérez
- Grupo de Biogeografía, Conservación y Territorio, Universidad de Las Palmas de Gran Canaria (ULPGC), Las Palmas de Gran Canaria, Gran Canaria, Canary Islands, Spain
| | - P A Sosa
- Grupo de Biogeografía, Conservación y Territorio, Universidad de Las Palmas de Gran Canaria (ULPGC), Las Palmas de Gran Canaria, Gran Canaria, Canary Islands, Spain
| |
Collapse
|
13
|
Gerber S, Chadœuf J, Gugerli F, Lascoux M, Buiteveld J, Cottrell J, Dounavi A, Fineschi S, Forrest LL, Fogelqvist J, Goicoechea PG, Jensen JS, Salvini D, Vendramin GG, Kremer A. High rates of gene flow by pollen and seed in oak populations across Europe. PLoS One 2014; 9:e85130. [PMID: 24454802 PMCID: PMC3890301 DOI: 10.1371/journal.pone.0085130] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 11/10/2013] [Indexed: 11/18/2022] Open
Abstract
Gene flow is a key factor in the evolution of species, influencing effective population size, hybridisation and local adaptation. We analysed local gene flow in eight stands of white oak (mostly Quercus petraea and Q. robur, but also Q. pubescens and Q. faginea) distributed across Europe. Adult trees within a given area in each stand were exhaustively sampled (range [239, 754], mean 423), mapped, and acorns were collected ([17,147], 51) from several mother trees ([3], [47], 23). Seedlings ([65,387], 178) were harvested and geo-referenced in six of the eight stands. Genetic information was obtained from screening distinct molecular markers spread across the genome, genotyping each tree, acorn or seedling. All samples were thus genotyped at 5–8 nuclear microsatellite loci. Fathers/parents were assigned to acorns and seedlings using likelihood methods. Mating success of male and female parents, pollen and seed dispersal curves, and also hybridisation rates were estimated in each stand and compared on a continental scale. On average, the percentage of the wind-borne pollen from outside the stand was 60%, with large variation among stands (21–88%). Mean seed immigration into the stand was 40%, a high value for oaks that are generally considered to have limited seed dispersal. However, this estimate varied greatly among stands (20–66%). Gene flow was mostly intraspecific, with large variation, as some trees and stands showed particularly high rates of hybridisation. Our results show that mating success was unevenly distributed among trees. The high levels of gene flow suggest that geographically remote oak stands are unlikely to be genetically isolated, questioning the static definition of gene reserves and seed stands.
Collapse
Affiliation(s)
- Sophie Gerber
- BIOGECO, UMR1202, INRA, Cestas, France ; BIOGECO, UMR1202, University of Bordeaux, Talence, France
| | | | - Felix Gugerli
- Biodiversity and Conservation Biology, WSL Swiss Federal Research Institute, Birmensdorf, Switzerland
| | - Martin Lascoux
- Department of Ecology and Genetics, EBC, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | | | - Joan Cottrell
- Forest Research, Northern Research Station, Roslin, Midlothian, Scotland, United Kingdom
| | - Aikaterini Dounavi
- Biodiversity and Conservation Biology, WSL Swiss Federal Research Institute, Birmensdorf, Switzerland
| | - Silvia Fineschi
- Institute for Plant Protection, CNR, Sesto Fiorentino (Firenze), Italy
| | - Laura L Forrest
- Forest Research, Northern Research Station, Roslin, Midlothian, Scotland, United Kingdom
| | - Johan Fogelqvist
- Department of Ecology and Genetics, EBC, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | | | | | - Daniela Salvini
- Institute for Plant Protection, CNR, Sesto Fiorentino (Firenze), Italy ; Forest & Landscape, University of Copenhagen, Copenhagen, Denmark
| | - Giovanni G Vendramin
- Institute of Biosciences and Bioresources, CNR, Sesto Fiorentino (Firenze), Italy
| | - Antoine Kremer
- BIOGECO, UMR1202, INRA, Cestas, France ; BIOGECO, UMR1202, University of Bordeaux, Talence, France
| |
Collapse
|
14
|
Robledo-Arnuncio JJ, Klein EK, Muller-Landau HC, Santamaría L. Space, time and complexity in plant dispersal ecology. MOVEMENT ECOLOGY 2014; 2:16. [PMID: 25709828 PMCID: PMC4337469 DOI: 10.1186/s40462-014-0016-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 07/24/2014] [Indexed: 05/09/2023]
Abstract
Dispersal of pollen and seeds are essential functions of plant species, with far-reaching demographic, ecological and evolutionary consequences. Interest in plant dispersal has increased with concerns about the persistence of populations and species under global change. We argue here that advances in plant dispersal ecology research will be determined by our ability to surmount challenges of spatiotemporal scales and heterogeneities and ecosystem complexity. Based on this framework, we propose a selected set of research questions, for which we suggest some specific objectives and methodological approaches. Reviewed topics include multiple vector contributions to plant dispersal, landscape-dependent dispersal patterns, long-distance dispersal events, spatiotemporal variation in dispersal, and the consequences of dispersal for plant communities, populations under climate change, and anthropogenic landscapes.
Collapse
Affiliation(s)
- Juan J Robledo-Arnuncio
- />Department of Forest Ecology & Genetics, INIA-CIFOR, Ctra. de la Coruña km 7.5, 28040 Madrid, Spain
| | - Etienne K Klein
- />INRA, UR546 Biostatistique et Processus Spatiaux (BioSP), Avignon, France
| | - Helene C Muller-Landau
- />Smithsonian Tropical Research Institute, Apartado Postal 0843-03092 Panamá, Republica de Panamá
| | - Luis Santamaría
- />Spatial Ecology Group, Doñana Biological Station (EBD-CSIC), Sevilla, Spain
| |
Collapse
|
15
|
Chybicki IJ. Note on the Applicability of the F-model in Analysis of Pollen Pool Heterogeneity. J Hered 2013; 104:578-85. [DOI: 10.1093/jhered/est029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
16
|
Jay F, Sjödin P, Jakobsson M, Blum MGB. Anisotropic isolation by distance: the main orientations of human genetic differentiation. Mol Biol Evol 2012; 30:513-25. [PMID: 23171862 PMCID: PMC3563970 DOI: 10.1093/molbev/mss259] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Genetic differentiation among human populations is greatly influenced by geography due to the accumulation of local allele frequency differences. However, little is known about the possibly different increment of genetic differentiation along the different geographical axes (north–south, east–west, etc.). Here, we provide new methods to examine the asymmetrical patterns of genetic differentiation. We analyzed genome-wide polymorphism data from populations in Africa (n = 29), Asia (n = 26), America (n = 9), and Europe (n = 38), and we found that the major orientations of genetic differentiation are north–south in Europe and Africa, and east–west in Asia, but no preferential orientation was found in the Americas. Additionally, we showed that the localization of the individual geographic origins based on single nucleotide polymorphism data was not equally precise along all orientations. Confirming our findings, we obtained that, in each continent, the orientation along which the precision is maximal corresponds to the orientation of maximum differentiation. Our results have implications for interpreting human genetic variation in terms of isolation by distance and spatial range expansion processes. In Europe, for instance, the precise northnorthwest–southsoutheast axis of main European differentiation cannot be explained by a simple Neolithic demic diffusion model without admixture with the local populations because in that case the orientation of greatest differentiation should be perpendicular to the direction of expansion. In addition to humans, anisotropic analyses can guide the description of genetic differentiation for other organisms and provide information on expansions of invasive species or the processes of plant dispersal.
Collapse
Affiliation(s)
- Flora Jay
- Department of Integrative Biology, University of California, Berkeley, CA, USA
| | | | | | | |
Collapse
|
17
|
Albaladejo RG, Guzmán B, González-Martínez SC, Aparicio A. Extensive pollen flow but few pollen donors and high reproductive variance in an extremely fragmented landscape. PLoS One 2012; 7:e49012. [PMID: 23152842 PMCID: PMC3495779 DOI: 10.1371/journal.pone.0049012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 10/03/2012] [Indexed: 12/01/2022] Open
Abstract
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 (Nep) 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 (δ = 229–412 m). However, they also agreed in detecting very few pollen donors (Nep = 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 (Sp = 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.
Collapse
Affiliation(s)
- Rafael G Albaladejo
- Department of Plant Biology and Ecology, School of Pharmacy, University of Seville, Seville, Spain.
| | | | | | | |
Collapse
|
18
|
McCauley RA, Christie BJ, Ireland EL, Landers RA, Nichols HR, Schendel MT. Influence of Relictual Species on the Morphology of a Hybridizing Oak Complex: An Analysis of theQuercusX UndulataComplex in the Four Corners Region. WEST N AM NATURALIST 2012. [DOI: 10.3398/064.072.0304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
19
|
van Putten B, Visser MD, Muller-Landau HC, Jansen PA. Distorted-distance models for directional dispersal: a general framework with application to a wind-dispersed tree. Methods Ecol Evol 2012. [DOI: 10.1111/j.2041-210x.2012.00208.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
20
|
Smouse PE, Sork VL, Scofield DG, Grivet D. Using Seedling and Pericarp Tissues to Determine Maternal Parentage of Dispersed Valley Oak Recruits. J Hered 2012; 103:250-9. [DOI: 10.1093/jhered/esr141] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
21
|
Born C, Le Roux PC, Spohr C, McGeoch MA, Van Vuuren BJ. Plant dispersal in the sub-Antarctic inferred from anisotropic genetic structure. Mol Ecol 2011; 21:184-94. [PMID: 22129220 DOI: 10.1111/j.1365-294x.2011.05372.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Climatic conditions and landscape features often strongly affect species' local distribution patterns, dispersal, reproduction and survival and may therefore have considerable impacts on species' fine-scale spatial genetic structure (SGS). In this study, we demonstrate the efficacy of combining fine-scale SGS analyses with isotropic and anisotropic spatial autocorrelation techniques to infer the impact of wind patterns on plant dispersal processes. We genotyped 1304 Azorella selago (Apiaceae) specimens, a wind-pollinated and wind-dispersed plant, from four populations distributed across sub-Antarctic Marion Island. SGS was variable with Sp values ranging from 0.001 to 0.014, suggesting notable variability in dispersal distance and wind velocities between sites. Nonetheless, the data supported previous hypotheses of a strong NW-SE gradient in wind strength across the island. Anisotropic autocorrelation analyses further suggested that dispersal is strongly directional, but varying between sites depending on the local prevailing winds. Despite the high frequency of gale-force winds on Marion Island, gene dispersal distance estimates (σ) were surprisingly low (<10 m), most probably because of a low pollen dispersal efficiency. An SGS approach in association with isotropic and anisotropic analyses provides a powerful means to assess the relative influence of abiotic factors on dispersal and allow inferences that would not be possible without this combined approach.
Collapse
Affiliation(s)
- Céline Born
- Evolutionary Genomics Group, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa.
| | | | | | | | | |
Collapse
|
22
|
Effects of male fecundity, interindividual distance and anisotropic pollen dispersal on mating success in a Scots pine (Pinus sylvestris) seed orchard. Heredity (Edinb) 2011; 108:312-21. [PMID: 21897440 DOI: 10.1038/hdy.2011.76] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Quantifying the effect of pollen dispersal and flowering traits on mating success is essential for understanding evolutionary responses to changing environments and establishing strategies for forest tree breeding. This study examined, quantitatively, the effects of male fecundity, interindividual distance and anisotropic pollen dispersal on the mating success of Scots pine (Pinus sylvestris), utilizing a well-mapped Scots pine seed orchard. Paternity analysis of 1021 seeds sampled from 87 trees representing 28 clones showed that 53% of the seeds had at least one potential pollen parent within the orchard. Pronounced variation in paternal contribution was observed among clones. Variations in pollen production explained up to 78% of the variation in mating success, which was 11.2 times greater for clones producing the largest amount of pollen than for clones producing the least pollen. Mating success also varied with intertree distance and direction, which explained up to 28% of the variance. Fertilization between neighboring trees 2.3 m apart was 2.4 times more frequent than between trees 4.6 m apart, and up to 12.4 times higher for trees downwind of the presumed prevailing wind direction than for upwind trees. The effective number of pollen donors recorded in the seed orchard (12.2) was smaller than the theoretical expectation (19.7). Based on the empirical observations, a mating model that best describes the gene dispersal pattern in clonal seed orchards was constructed.
Collapse
|
23
|
Exploring demographic, physical, and historical explanations for the genetic structure of two lineages of Greater Antillean bats. PLoS One 2011; 6:e17704. [PMID: 21445291 PMCID: PMC3061861 DOI: 10.1371/journal.pone.0017704] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Accepted: 02/08/2011] [Indexed: 11/19/2022] Open
Abstract
Observed patterns of genetic structure result from the interactions of demographic, physical, and historical influences on gene flow. The particular strength of various factors in governing gene flow, however, may differ between species in biologically relevant ways. We investigated the role of demographic factors (population size and sex-biased dispersal) and physical features (geographic distance, island size and climatological winds) on patterns of genetic structure and gene flow for two lineages of Greater Antillean bats. We used microsatellite genetic data to estimate demographic characteristics, infer population genetic structure, and estimate gene flow among island populations of Erophylla sezekorni/E. bombifrons and Macrotus waterhousii (Chiroptera: Phyllostomidae). Using a landscape genetics approach, we asked if geographic distance, island size, or climatological winds mediate historical gene flow in this system. Samples from 13 islands spanning Erophylla's range clustered into five genetically distinct populations. Samples of M. waterhousii from eight islands represented eight genetically distinct populations. While we found evidence that a majority of historical gene flow between genetic populations was asymmetric for both lineages, we were not able to entirely rule out incomplete lineage sorting in generating this pattern. We found no evidence of contemporary gene flow except between two genetic populations of Erophylla. Both lineages exhibited significant isolation by geographic distance. Patterns of genetic structure and gene flow, however, were not explained by differences in relative effective population sizes, island area, sex-biased dispersal (tested only for Erophylla), or surface-level climatological winds. Gene flow among islands appears to be highly restricted, particularly for M. waterhousii, and we suggest that this species deserves increased taxonomic attention and conservation concern.
Collapse
|
24
|
Kettle CJ, Maycock CR, Ghazoul J, Hollingsworth PM, Khoo E, Sukri RSH, Burslem DFRP. Ecological implications of a flower size/number trade-off in tropical forest trees. PLoS One 2011; 6:e16111. [PMID: 21408110 PMCID: PMC3052255 DOI: 10.1371/journal.pone.0016111] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 12/12/2010] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND In angiosperms, flower size commonly scales negatively with number. The ecological consequences of this trade-off for tropical trees remain poorly resolved, despite their potential importance for tropical forest conservation. We investigated the flower size number trade-off and its implications for fecundity in a sample of tree species from the Dipterocarpaceae on Borneo. METHODOLOGY/PRINCIPAL FINDINGS We combined experimental exclusion of pollinators in 11 species, with direct and indirect estimates of contemporary pollen dispersal in two study species and published estimates of pollen dispersal in a further three species to explore the relationship between flower size, pollinator size and mean pollen dispersal distance. Maximum flower production was two orders of magnitude greater in small-flowered than large-flowered species of Dipterocarpaceae. In contrast, fruit production was unrelated to flower size and did not differ significantly among species. Small-flowered species had both smaller-sized pollinators and lower mean pollination success than large-flowered species. Average pollen dispersal distances were lower and frequency of mating between related individuals was higher in a smaller-flowered species than a larger-flowered confamilial. Our synthesis of pollen dispersal estimates across five species of dipterocarp suggests that pollen dispersal scales positively with flower size. CONCLUSIONS AND THEIR SIGNIFICANCE Trade-offs embedded in the relationship between flower size and pollination success contribute to a reduction in the variance of fecundity among species. It is therefore plausible that these processes could delay competitive exclusion and contribute to maintenance of species coexistence in this ecologically and economically important family of tropical trees. These results have practical implications for tree species conservation and restoration. Seed collection from small-flowered species may be especially vulnerable to cryptic genetic erosion. Our findings also highlight the potential for differential vulnerability of tropical tree species to the deleterious consequences of forest fragmentation.
Collapse
Affiliation(s)
- Chris J Kettle
- Ecosystem Management, Institute of Terrestrial Ecosystems, ETH Zurich, Zurich, Switzerland.
| | | | | | | | | | | | | |
Collapse
|
25
|
GRIVET DELPHINE, ROBLEDO-ARNUNCIO JUANJ, SMOUSE PETERE, SORK VICTORIAL. Relative contribution of contemporary pollen and seed dispersal to the effective parental size of seedling population of California valley oak (Quercus lobata, Née). Mol Ecol 2009; 18:3967-79. [DOI: 10.1111/j.1365-294x.2009.04326.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|