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Gómez JM, Muñoz-Pajares AJ, Abdelaziz M, Lorite J, Perfectti F. Evolution of pollination niches and floral divergence in the generalist plant Erysimum mediohispanicum. ANNALS OF BOTANY 2014; 113:237-49. [PMID: 23965614 PMCID: PMC3890381 DOI: 10.1093/aob/mct186] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 06/21/2013] [Indexed: 05/23/2023]
Abstract
BACKGROUND AND AIMS How generalist plants diverge in response to pollinator selection without becoming specialized is still unknown. This study explores this question, focusing on the evolution of the pollination system in the pollination generalist Erysimum mediohispanicum (Brassicaceae). METHODS Pollinator assemblages were surveyed from 2001 to 2010 in 48 geo-referenced populations covering the entire geographic distribution of E. mediohispanicum. Bipartite modularity, a complex network tool, was used to find the pollination niche of each population. Evolution of the pollination niches and the correlated evolution of floral traits and pollination niches were explored using within-species comparative analyses. KEY RESULTS Despite being generalists, the E. mediohispanicum populations studied can be classified into five pollination niches. The boundaries between niches were not sharp, the niches differing among them in the relative frequencies of the floral visitor functional groups. The absence of spatial autocorrelation and phylogenetic signal indicates that the niches were distributed in a phylogeographic mosaic. The ancestral E. mediohispanicum populations presumably belonged to the niche defined by a high number of beetle and ant visits. A correlated evolution was found between pollination niches and some floral traits, suggesting the existence of generalist pollination ecotypes. CONCLUSIONS It is conjectured that the geographic variation in pollination niches has contributed to the observed floral divergence in E. mediohispanicum. The process mediating this floral divergence presumably has been adaptive wandering, but the adaptation to the local pollinator faunas has been not universal. The outcome is a landscape where a few populations locally adapted to their pollination environment (generalist pollination ecotypes) coexist with many populations where this local adaptation has failed and where the plant phenotype is not primarily shaped by pollinators.
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Affiliation(s)
| | | | | | - J. Lorite
- Departamento de Botánica, Universidad de Granada, E-18071 Granada, Spain
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Masuda S, Tani N, Ueno S, Lee SL, Muhammad N, Kondo T, Numata S, Tsumura Y. Non-density dependent pollen dispersal of Shorea maxwelliana (Dipterocarpaceae) revealed by a Bayesian mating model based on paternity analysis in two synchronized flowering seasons. PLoS One 2013; 8:e82039. [PMID: 24391712 PMCID: PMC3876983 DOI: 10.1371/journal.pone.0082039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 10/20/2013] [Indexed: 11/18/2022] Open
Abstract
Pollinator syndrome is one of the most important determinants regulating pollen dispersal in tropical tree species. It has been widely accepted that the reproduction of tropical forest species, especially dipterocarps that rely on insects with weak flight for their pollination, is positively density-dependent. However differences in pollinator syndrome should affect pollen dispersal patterns and, consequently, influence genetic diversity via the mating process. We examined the pollen dispersal pattern and mating system of Shorea maxwelliana, the flowers of which are larger than those of Shorea species belonging to section Mutica which are thought to be pollinated by thrips (weak flyers). A Bayesian mating model based on the paternity of seeds collected from mother trees during sporadic and mass flowering events revealed that the estimated pollen dispersal kernel and average pollen dispersal distance were similar for both flowering events. This evidence suggests that the putative pollinators – small beetles and weevils – effectively contribute to pollen dispersal and help to maintain a high outcrossing rate even during sporadic flowering events. However, the reduction in pollen donors during a sporadic event results in a reduction in effective pollen donors, which should lead to lower genetic diversity in the next generation derived from seeds produced during such an event. Although sporadic flowering has been considered less effective for outcrossing in Shorea species that depend on thrips for their pollination, effective pollen dispersal by the small beetles and weevils ensures outcrossing during periods of low flowering tree density, as occurs in a sporadic flowering event.
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Affiliation(s)
- Shinsuke Masuda
- School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Naoki Tani
- Forestry Division, Japan International Research Center for Agricultural Sciences, Tsukuba, Ibaraki, Japan
- Forestry Biotechnology Division, Forest Research Institute Malaysia, Kepong, Selangor Darul Ehsan, Malaysia
- * E-mail: (NT); (YT)
| | - Saneyoshi Ueno
- Department of Forest Genetics, Forestry and Forest Products Research Institute, Tsukuba, Japan
| | - Soon Leong Lee
- Forestry Biotechnology Division, Forest Research Institute Malaysia, Kepong, Selangor Darul Ehsan, Malaysia
| | - Norwati Muhammad
- Forestry Biotechnology Division, Forest Research Institute Malaysia, Kepong, Selangor Darul Ehsan, Malaysia
| | - Toshiaki Kondo
- Graduate School for International Development and Cooperation, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Shinya Numata
- Faculty and Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, Japan
| | - Yoshihiko Tsumura
- School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Department of Forest Genetics, Forestry and Forest Products Research Institute, Tsukuba, Japan
- * E-mail: (NT); (YT)
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Vanbergen AJ, Woodcock BA, Gray A, Grant F, Telford A, Lambdon P, Chapman DS, Pywell RF, Heard MS, Cavers S. Grazing alters insect visitation networks and plant mating systems. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12191] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Adam J. Vanbergen
- NERC Centre for Ecology and Hydrology Bush Estate Penicuik Edinburgh EH26 0QB UK
| | - Ben A. Woodcock
- NERC Centre for Ecology and Hydrology Maclean Building Benson Lane Crowmarsh Gifford Wallingford OX10 8BB UK
| | - Alan Gray
- NERC Centre for Ecology and Hydrology Bush Estate Penicuik Edinburgh EH26 0QB UK
| | - Fiona Grant
- NERC Centre for Ecology and Hydrology Bush Estate Penicuik Edinburgh EH26 0QB UK
| | - Annika Telford
- NERC Centre for Ecology and Hydrology Bush Estate Penicuik Edinburgh EH26 0QB UK
| | - Phil Lambdon
- NERC Centre for Ecology and Hydrology Bush Estate Penicuik Edinburgh EH26 0QB UK
| | - Dan S. Chapman
- NERC Centre for Ecology and Hydrology Bush Estate Penicuik Edinburgh EH26 0QB UK
| | - Richard F. Pywell
- NERC Centre for Ecology and Hydrology Maclean Building Benson Lane Crowmarsh Gifford Wallingford OX10 8BB UK
| | - Matt S. Heard
- NERC Centre for Ecology and Hydrology Maclean Building Benson Lane Crowmarsh Gifford Wallingford OX10 8BB UK
| | - Stephen Cavers
- NERC Centre for Ecology and Hydrology Bush Estate Penicuik Edinburgh EH26 0QB UK
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Polatto LP, Chaud-Netto J. Influence of Apis mellifera L. (Hymenoptera: Apidae) on the Use of the Most Abundant and Attractive Floral Resources in a Plant Community. NEOTROPICAL ENTOMOLOGY 2013; 42:576-587. [PMID: 27193275 DOI: 10.1007/s13744-013-0165-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 08/18/2013] [Indexed: 06/05/2023]
Abstract
Some factors influence the distribution of abundance of floral visitors, especially the amount and quality of the floral resources available, the size of the area occupied by the visitor, habitat heterogeneity, and the impact caused by natural enemies and introduced species. The objective of this research was to evaluate the distribution of abundance of the foraging activity of native floral visitors and Apis mellifera L. in the most abundant and attractive food sources in a secondary forest fragment with features of Cerrado-Atlantic Forest. Some plant species were selected and the frequency of foraging made by floral visitors was recorded. A high abundance of visits in flowers was performed by A. mellifera. Two factors may have influenced this result: (1) the occupation of the forest fragment predominantly by vines and shrubs at the expenses of vegetation with arboreal characteristics that favored the encounter of the flowering plants by A. mellifera; (2) rational beekeeping of A. mellifera, causing the number of natural swarms which originate annually from colonies of commercial apiaries and colonies previously established in the environment to be very high, thus leading to an increase in the population size of this bee species in the study site. The frequent occurrence of human-induced fire and deforestation within the forest fragment may have reduced the population size of the bee species, including A. mellifera. As the populations of A. mellifera have the capacity to quickly occupy the environment, this species possibly became dominant after successive disturbances made in the forest fragment.
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Affiliation(s)
- L P Polatto
- Depto de Biologia do Instituto de Biociências, Univ Estadual Paulista (UNESP), Rio Claro, SP, Brasil.
- Univ Estadual de Mato Grosso do Sul (UEMS), Unidade Universitária de Ivinhema, Av. Brasil, 679, 79.740-000, Ivinhema, MS, Brasil.
| | - J Chaud-Netto
- Depto de Biologia do Instituto de Biociências, Univ Estadual Paulista (UNESP), Rio Claro, SP, Brasil
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Chumacero de Schawe C, Durka W, Tscharntke T, Hensen I, Kessler M. Gene flow and genetic diversity in cultivated and wild cacao (Theobroma cacao) in Bolivia. AMERICAN JOURNAL OF BOTANY 2013; 100:2271-2279. [PMID: 24158148 DOI: 10.3732/ajb.1300025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
PREMISE OF THE STUDY The role of pollen flow within and between cultivated and wild tropical crop species is little known. To study the pollen flow of cacao, we estimated the degree of self-pollination and pollen dispersal distances as well as gene flow between wild and cultivated cacao (Theobroma cacao L.). METHODS We studied pollen flow and genetic diversity of cultivated and wild cacao populations by genotyping 143 wild and 86 cultivated mature plants and 374 seedlings raised from 19 wild and 25 cultivated trees at nine microsatellite loci. KEY RESULTS A principal component analysis distinguished wild and cultivated cacao trees, supporting the notion that Bolivia harbors truly wild cacao populations. Cultivated cacao had a higher level of genetic diversity than wild cacao, presumably reflecting the varied origin of cultivated plants. Both cacao types had high outcrossing rates, but the paternity analysis revealed 7-14% self-pollination in wild and cultivated cacao. Despite the tiny size of the pollinators, pollen was transported distances up to 3 km; wild cacao showed longer distances (mean = 922 m) than cultivated cacao (826 m). Our data revealed that 16-20% of pollination events occurred between cultivated and wild populations. CONCLUSIONS We found evidence of self-pollination in both wild and cultivated cacao. Pollination distances are larger than those typically reported in tropical understory tree species. The relatively high pollen exchange from cultivated to wild cacao compromises genetic identity of wild populations, calling for the protection of extensive natural forest tracts to protect wild cacao in Bolivia.
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Grogan J, Loveless MD. Flowering phenology and its implications for management of big-leaf mahogany Swietenia macrophylla in Brazilian Amazonia. AMERICAN JOURNAL OF BOTANY 2013; 100:2293-2305. [PMID: 24214531 DOI: 10.3732/ajb.1300087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
PREMISE OF THE STUDY Flowering phenology is a crucial determinant of reproductive success and offspring genetic diversity in plants. We measure the flowering phenology of big-leaf mahogany (Swietenia macrophylla, Meliaceae), a widely distributed neotropical tree, and explore how disturbance from logging impacts its reproductive biology. METHODS We use a crown scoring system to estimate the timing and duration of population-level flowering at three forest sites in the Brazilian Amazon over a five-year period. We combine this information with data on population structure and spatial distribution to consider the implications of logging for population flowering patterns and reproductive success. KEY RESULTS Mahogany trees as small as 14 cm diam flowered, but only trees > 30 cm diam flowered annually or supra-annually. Mean observed flowering periods by focal trees ranged from 18-34 d, and trees flowered sequentially during 3-4 mo beginning in the dry season. Focal trees demonstrated significant interannual correlation in flowering order. Estimated population-level flowering schedules resembled that of the focal trees, with temporal isolation between early and late flowering trees. At the principal study site, conventional logging practices eliminated 87% of mahogany trees > 30 cm diam and an estimated 94% of annual pre-logging floral effort. CONCLUSIONS Consistent interannual patterns of sequential flowering among trees create incompletely isolated subpopulations, constraining pollen flow. After harvests, surviving subcommercial trees will have fewer, more distant, and smaller potential partners, with probable consequences for post-logging regeneration. These results have important implications for the sustainability of harvesting systems for tropical timber species.
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Affiliation(s)
- James Grogan
- Mount Holyoke College, Department of Biology, South Hadley, Massachusetts 01075 USA
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Côrtes MC, Uriarte M, Lemes MR, Gribel R, John Kress W, Smouse PE, Bruna EM. Low plant density enhances gene dispersal in the Amazonian understory herbHeliconia acuminata. Mol Ecol 2013; 22:5716-29. [DOI: 10.1111/mec.12495] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Marina C. Côrtes
- Department of Ecology, Evolution and Environmental Biology; Columbia University; 1200 Amsterdam Avenue New York NY 10027 USA
- Biological Dynamics of Forest Fragments Project; Instituto Nacional de Pesquisas da Amazônia and Smithsonian Tropical Research Institute; Av. André Araujo 2936 Manaus AM 69083-000 Brazil
| | - María Uriarte
- Department of Ecology, Evolution and Environmental Biology; Columbia University; 1200 Amsterdam Avenue New York NY 10027 USA
| | - Maristerra R. Lemes
- Laboratório de Genética e Biologia Reprodutiva de Plantas; Instituto Nacional de Pesquisas da Amazônia; Av. André Araujo 2936 Manaus AM 69083-000 Brazil
- Instituto de Pesquisas Jardim Botânico do Rio de Janeiro; Rua Jardim Botânico 1008 Rio de Janeiro RJ 22460-030 Brazil
| | - Rogério Gribel
- Laboratório de Genética e Biologia Reprodutiva de Plantas; Instituto Nacional de Pesquisas da Amazônia; Av. André Araujo 2936 Manaus AM 69083-000 Brazil
- Instituto de Pesquisas Jardim Botânico do Rio de Janeiro; Rua Jardim Botânico 1008 Rio de Janeiro RJ 22460-030 Brazil
| | - W. John Kress
- Department of Botany; National Museum of Natural History; MRC-166; Smithsonian Institution; PO Box 37012 Washington DC USA
| | - Peter E. Smouse
- Department of Ecology, Evolution and Natural Resources; Rutgers University; 14 College Farm Road New Brunswick NJ 08901-8551 USA
| | - Emilio M. Bruna
- Biological Dynamics of Forest Fragments Project; Instituto Nacional de Pesquisas da Amazônia and Smithsonian Tropical Research Institute; Av. André Araujo 2936 Manaus AM 69083-000 Brazil
- Department of Wildlife Ecology and Conservation; University of Florida; 711 Newell Drive Gainesville FL 32611-0430 USA
- Center for Latin American Studies; University of Florida; 319 Grinter Hall Gainesville FL 32611 USA
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58
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Krupnick GA. Conservation of Tropical Plant Biodiversity: What Have We Done, Where Are We Going? Biotropica 2013. [DOI: 10.1111/btp.12064] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gary A. Krupnick
- Department of Botany; National Museum of Natural History; Smithsonian Institution; P.O. Box 37012 Washington DC 20013-7012 U.S.A
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González-Varo JP, Biesmeijer JC, Bommarco R, Potts SG, Schweiger O, Smith HG, Steffan-Dewenter I, Szentgyörgyi H, Woyciechowski M, Vilà M. Combined effects of global change pressures on animal-mediated pollination. Trends Ecol Evol 2013; 28:524-30. [DOI: 10.1016/j.tree.2013.05.008] [Citation(s) in RCA: 211] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 05/02/2013] [Accepted: 05/03/2013] [Indexed: 10/26/2022]
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Banks SC, Lindenmayer DB. Inbreeding avoidance, patch isolation and matrix permeability influence dispersal and settlement choices by male agile antechinus in a fragmented landscape. J Anim Ecol 2013; 83:515-24. [PMID: 23991826 DOI: 10.1111/1365-2656.12128] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 07/16/2013] [Indexed: 11/30/2022]
Abstract
Animal dispersal is highly non-random and has important implications for the dynamics of populations in fragmented habitat. We identified interpatch dispersal events from genetic tagging, parentage analyses and assignment tests and modelled the factors associated with apparent emigration and post-dispersal settlement choices by individual male agile antechinus (Antechinus agilis, a marsupial carnivore of south-east Australian forests). Emigration decisions were best modelled with on data patch isolation and inbreeding risk. The choice of dispersal destination by males was influenced by inbreeding risk, female abundance, patch size, patch quality and matrix permeability (variation in land cover). Males were less likely to settle in patches without highly unrelated females. Our findings highlight the importance of individual-level dispersal data for understanding how multiple processes drive non-randomness in dispersal in modified landscapes. Fragmented landscapes present novel environmental, demographic and genetic contexts in which dispersal decisions are made, so the major factors affecting dispersal decisions in fragmented habitat may differ considerably from unfragmented landscapes. We show that the spatial scale of genetic neighbourhoods can be large in fragmented habitat, such that dispersing males can potentially settle in the presence of genetically similar females after moving considerable distances, thereby necessitating both a choice to emigrate and a choice of where to settle to avoid inbreeding.
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Affiliation(s)
- Sam C Banks
- The Fenner School of Environment and Society, The Australian National University.,Australian Research Council Centre of Excellence for Environmental Decisions, National Environmental Research Program Environmental Decisions Hub, Australia
| | - David B Lindenmayer
- The Fenner School of Environment and Society, The Australian National University.,Australian Research Council Centre of Excellence for Environmental Decisions, National Environmental Research Program Environmental Decisions Hub, Australia
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Herrera-Arroyo ML, Sork VL, González-Rodríguez A, Rocha-Ramírez V, Vega E, Oyama K. Seed-mediated connectivity among fragmented populations of Quercus castanea (Fagaceae) in a Mexican landscape. AMERICAN JOURNAL OF BOTANY 2013; 100:1663-1671. [PMID: 23942083 DOI: 10.3732/ajb.1200396] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
PREMISE OF STUDY Anthropogenic fragmentation is an ongoing process in many forested areas that may create loss of connectivity among tree populations and constitutes a serious threat to ecological and genetic processes. We tested the central hypothesis that seed dispersal mitigates the impact of fragmentation by comparing connectivity and genetic diversity of adult vs. seedling populations in recently fragmented populations of the Mexican red oak Quercus castanea. METHODS Adult individuals, established before fragmentation, and seedlings, established after fragmentation, were sampled at 33 forest fragments of variable size (0.2 to 294 ha) within the Cuitzeo basin, Michoacán state, and genotyped using seven highly polymorphic chloroplast microsatellite markers (cpSSRs). To test whether seed dispersal retains connectivity among fragmented populations, we compared genetic diversity and connectivity networks between adults and progeny and determined the effect of fragment size on these values. KEY RESULTS Seventy haplotypes were identified, 63 in the adults and 60 in the seedlings, with average within-population diversity (hS) values of 0.624 in the adults and 0.630 in the seedlings. A positive correlation of genetic diversity values with fragment size was found in the seedling populations but not in the adult populations. The network connectivity analysis revealed lower connectivity among seedling populations than among adults. The number of connections (edges) as well as other network properties, such as betweenness centrality, node degree and closeness, were significantly lower in the seedlings network. CONCLUSIONS Habitat fragmentation in this landscape is disrupting seed-dispersal-mediated genetic connectivity among extant populations.
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Affiliation(s)
- M Luisa Herrera-Arroyo
- Centro de Investigaciones en Ecosistemas. Universidad Nacional Autónoma de México UNAM, Antigua carretera a Pátzcuaro no. 8701, Col. Ex-hacienda San José de la Huerta, Morelia 58190 Michoacán, México
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Quesada M, Herrerías-Diego Y, Lobo JA, Sánchez-Montoya G, Rosas F, Aguilar R. Long-term effects of habitat fragmentation on mating patterns and gene flow of a tropical dry forest tree, Ceiba aesculifolia (Malvaceae: Bombacoideae). AMERICAN JOURNAL OF BOTANY 2013; 100:1095-1101. [PMID: 23720432 DOI: 10.3732/ajb.1200542] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
PREMISE OF THE STUDY Tropical forest loss and fragmentation isolate and reduce the size of remnant populations with negative consequences for mating patterns and genetic structure of plant species. In a 4-yr study, we determined the effect of fragmentation on mating patterns and pollen pool genetic structure of the tropical tree Ceiba aesculifolia in two habitat conditions: isolated trees in disturbed areas (≤3 trees/ha), and trees (≥6 trees/ha) in undisturbed mature forest. • METHODS Using six allozyme loci, we estimated the outcrossing rate (tm), the mean relatedness of progeny (rp) within and between fruits, the degree of genetic structure of pollen pools (Φft), and the effective number of pollen donors (Nep). • KEY RESULTS The outcrossing rates reflected a strict self-incompatible species. Relatedness of progeny within fruits was similar for all populations, revealing single sires within fruits. However, relatedness of progeny between fruits within trees was consistently greater for trees in fragmented conditions across 4 yr. We found high levels of genetic structure of pollen pools in all populations with more structure in isolated trees. The effective number of pollen donors was greater for trees in undisturbed forest than in disturbed conditions. • CONCLUSIONS Our study showed that the progeny produced by isolated trees in disturbed habitats are sired by a fraction of the diversity of pollen donors found in conserved forests. The foraging behavior of bats limits the exchange of pollen between trees, causing higher levels of progeny relatedness in isolated trees.
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Affiliation(s)
- Mauricio Quesada
- Centro de Investigaciones en Ecosistemas, Universidad Nacional Autónoma de México, Campus Morelia. Apartado Postal 27-3 (Xangari), Morelia, Michoacán, México 58089.
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Berens DG, Griebeler EM, Braun C, Chituyi BB, Nathan R, Böhning-Gaese K. Changes of effective gene dispersal distances by pollen and seeds across successive life stages in a tropical tree. OIKOS 2013. [DOI: 10.1111/j.1600-0706.2013.00515.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abe H, Ueno S, Takahashi T, Tsumura Y, Hasegawa M. Resilient plant-bird interactions in a volcanic island ecosystem: pollination of Japanese Camellia mediated by the Japanese White-eye. PLoS One 2013; 8:e62696. [PMID: 23646136 PMCID: PMC3639980 DOI: 10.1371/journal.pone.0062696] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 03/25/2013] [Indexed: 11/25/2022] Open
Abstract
Observations of interspecies interactions during volcanic activity provide important opportunities to study how organisms respond to environmental devastation. Japanese camellia (Camellia japonica L.) and its main avian pollinator, the Japanese White-eye (Zosterops japonica), offer an excellent example of such an interaction as key members of the biotic community on Miyake-jima, which erupted in 2000 and continues to emit volcanic gases. Both species exhibit higher resistance to volcanic damage than other species. We examined the effects of volcanic activity on this plant–pollinator system by estimating pollen flow and the genetic diversity of the next generation. The results showed that despite a decrease in Camellia flowers, the partitioning of allelic richness among mother-tree pollen pools and seeds decreased while the migration rate of pollen from outside the study plot and the pollen donor diversity within a fruit increased as the index of volcanic damage increased. In areas with low food (flower) density due to volcanic damage, Z. japonica ranged over larger areas to satisfy its energy needs rather than moving to areas with higher food density. Consequently, the genetic diversity of the seeds (the next plant generation) increased with the index of volcanic damage. The results were consistent with previously published data on the movement of Z. japonica based on radio tracking and the genetic diversity of Camellia pollen adhering to pollinators. Overall, our results indicated that compensation mechanisms ensured better pollination after volcanic disturbance.
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Affiliation(s)
- Harue Abe
- Field Center for Sustainable Agriculture and Forestry, Faculty of Agriculture, Niigata University, 94-2 Koda, Sado, Niigata, Japan.
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Setsuko S, Nagamitsu T, Tomaru N. Pollen flow and effects of population structure on selfing rates and female and male reproductive success in fragmented Magnolia stellata populations. BMC Ecol 2013; 13:10. [PMID: 23517612 PMCID: PMC3670206 DOI: 10.1186/1472-6785-13-10] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 03/07/2013] [Indexed: 11/10/2022] Open
Abstract
Background Fragmentation of plant populations may affect mating patterns and female and male reproductive success. To improve understanding of fragmentation effects on plant reproduction, we investigated the pollen flow patterns in six adjacent local populations of Magnolia stellata, an insect-pollinated, threatened tree species in Japan, and assessed effects of maternal plant (genet) size, local genet density, population size and neighboring population size on female reproductive success (seed production rates), and effects of mating distance, paternal genet size, population size and separation of populations on male reproductive success. Results The seed production rate, i.e. the proportion of ovules that successfully turned into seeds, varied between 1.0 and 6.5%, and increased with increasing population size and neighboring population size, and with decreasing maternal genet size and local genet density. The selfing rate varied between 3.6 and 28.9%, and increased with increasing maternal genet size and with declining local genet density. Male reproductive success increased with increasing paternal genet size, and decreased with increasing mating distance and separation of population. Pollen flow between the populations was low (6.1%) and highly leptocurtic. Conclusions Our results indicate that habitat fragmentation, separation and reduced size of populations, affected mating patterns and reproductive success of M. stellata. Local competition for pollinators and plant display size were likely to alter the reproductive success.
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Affiliation(s)
- Suzuki Setsuko
- Department of Forest Genetics, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan.
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Genetic diversity and the mating system in a fragmented population of Tsoongiodendron odorum. ACTA ACUST UNITED AC 2013. [DOI: 10.3724/sp.j.1003.2012.09083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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67
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Ismail SA, Ghazoul J, Ravikanth G, Uma Shaanker R, Kushalappa CG, Kettle CJ. Does long-distance pollen dispersal preclude inbreeding in tropical trees? Fragmentation genetics ofDysoxylum malabaricumin an agro-forest landscape. Mol Ecol 2012; 21:5484-96. [PMID: 23043256 DOI: 10.1111/mec.12054] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 08/28/2012] [Accepted: 09/04/2012] [Indexed: 11/28/2022]
Affiliation(s)
- S. A. Ismail
- Ecosystem Management; Department of Environmental Systems Science, ETH Zürich, Universitätsstrasse 16; CH-8092 Zurich; Switzerland
| | - J. Ghazoul
- Ecosystem Management; Department of Environmental Systems Science, ETH Zürich, Universitätsstrasse 16; CH-8092 Zurich; Switzerland
| | - G. Ravikanth
- Department of Conservation Genetics; Ashoka Trust for Research in Ecology and the Environment; Bangalore; Karnataka; India
| | - R. Uma Shaanker
- Department of Crop Physiology; University of Agricultural Sciences; Bangalore; Karnataka; India
| | - C. G. Kushalappa
- College of Forestry; University of Agricultural Sciences; Ponnampet; Karnataka; India
| | - C. J. Kettle
- Ecosystem Management; Department of Environmental Systems Science, ETH Zürich, Universitätsstrasse 16; CH-8092 Zurich; Switzerland
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68
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He R, Wang J, Huang H. Long-distance gene dispersal inferred from spatial genetic structure in Handeliodendron bodinieri, an endangered tree from karst forest in southwest China. BIOCHEM SYST ECOL 2012. [DOI: 10.1016/j.bse.2012.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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69
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Lasso E, Dalling JW, Bermingham E. Strong spatial genetic structure in five tropical Piper species: should the Baker-Fedorov hypothesis be revived for tropical shrubs? Ecol Evol 2012; 1:502-16. [PMID: 22393518 PMCID: PMC3287332 DOI: 10.1002/ece3.40] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 08/19/2011] [Accepted: 08/24/2011] [Indexed: 11/10/2022] Open
Abstract
Fifty years ago, Baker and Fedorov proposed that the high species diversity of tropical forests could arise from the combined effects of inbreeding and genetic drift leading to population differentiation and eventually to sympatric speciation. Decades of research, however have failed to support the Baker-Fedorov hypothesis (BFH), and it has now been discarded in favor of a paradigm where most trees are self-incompatible or strongly outcrossing, and where long-distance pollen dispersal prevents population drift. Here, we propose that several hyper-diverse genera of tropical herbs and shrubs, including Piper (>1,000 species), may provide an exception. Species in this genus often have aggregated, high-density populations with self-compatible breeding systems; characteristics which the BFH would predict lead to high local genetic differentiation. We test this prediction for five Piper species on Barro Colorado Island, Panama, using Amplified Fragment Length Polymorphism (AFLP) markers. All species showed strong genetic structure at both fine- and large-spatial scales. Over short distances (200-750 m) populations showed significant genetic differentiation (Fst 0.11-0.46, P < 0.05), with values of spatial genetic structure that exceed those reported for other tropical tree species (Sp = 0.03-0.136). This genetic structure probably results from the combined effects of limited seed and pollen dispersal, clonal spread, and selfing. These processes are likely to have facilitated the diversification of populations in response to local natural selection or genetic drift and may explain the remarkable diversity of this rich genus.
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70
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The pollen dispersal kernel and mating system of an insect-pollinated tropical palm, Oenocarpus bataua. Heredity (Edinb) 2012; 109:332-9. [PMID: 22892637 DOI: 10.1038/hdy.2012.40] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Pollen dispersal shapes the local genetic structure of plant populations and determines the opportunity for local selection and genetic drift, but has been well studied in few animal-pollinated plants in tropical rainforests. Here, we characterise pollen movement for an insect-pollinated Neotropical canopy palm, Oenocarpus bataua, and relate these data to adult mating system and population genetic structure. The study covers a 130-ha parcel in which all adult trees (n=185) were mapped and genotyped at 12 microsatellite loci, allowing us to positively identify the source tree for 90% of pollination events (n=287 of 318 events). Mating system analysis showed O. bataua was effectively outcrossed (t(m)=1.02) with little biparental inbreeding (t(m)-t(s)=-0.005) and an average of 5.4 effective pollen donors (N(ep)) per female. Dispersal distances were relatively large for an insect-pollinated species (mean=303 m, max=1263 m), and far exceeded nearest-neighbour distances. Dispersal kernel modelling indicated a thin-tailed Weibull distribution offered the best fit to the genetic data, which contrasts with the fat-tailed kernels typically reported for pollen dispersal in trees. Preliminary analyses suggest that our findings may be explained, at least in part, by a relatively diffuse spatial and temporal distribution of flowering trees. Comparison with previously reported estimates of seed movement for O. bataua suggests that pollen and seed dispersal distances may be similar. These findings add to the growing body of information on dispersal in insect-pollinated trees, but underscore the need for continued research on tropical systems in general, and palms in particular.
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71
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Wang R, Compton SG, Shi YS, Chen XY. Fragmentation reduces regional-scale spatial genetic structure in a wind-pollinated tree because genetic barriers are removed. Ecol Evol 2012; 2:2250-61. [PMID: 23139883 PMCID: PMC3488675 DOI: 10.1002/ece3.344] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 06/24/2012] [Accepted: 07/02/2012] [Indexed: 11/08/2022] Open
Abstract
Gene flow strongly influences the regional genetic structuring of plant populations. Seed and pollen dispersal patterns can respond differently to the increased isolation resulting from habitat fragmentation, with unpredictable consequences for gene flow and population structuring. In a recently fragmented landscape we compared the pre- and post-fragmentation genetic structure of populations of a tree species where pollen and seed dispersal respond differentially to forest fragmentation generated by flooding. Castanopsis sclerophylla is wind-pollinated, with seeds that are dispersed by gravity and rodents. Using microsatellites, we found no significant difference in genetic diversity between pre- and post-fragmentation cohorts. Significant genetic structure was observed in pre-fragmentation cohorts, due to an unknown genetic barrier that had isolated one small population. Among post-fragmentation cohorts this genetic barrier had disappeared and genetic structure was significantly weakened. The strengths of genetic structuring were at a similar level in both cohorts, suggesting that overall gene flow of C. sclerophylla has been unchanged by fragmentation at the regional scale. Fragmentation has blocked seed dispersal among habitats, but this appears to have been compensated for by enhanced pollen dispersal, as indicated by the disappearance of a genetic barrier, probably as a result of increased wind speeds and easier pollen movement over water. Extensive pollen flow can counteract some negative effects of fragmentation and assist the long-term persistence of small remnant populations.
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Affiliation(s)
- Rong Wang
- Tiantong National Observation Station of Forest Ecosystems, Department of Environmental Sciences, East China Normal University Shanghai, 200062, China ; School of Biology, Faculty of Biological Sciences, University of Leeds Leeds, LS2 9JT, UK
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72
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NEUSCHULZ EIKEL, GRASS INGO, BOTZAT ALEXANDRA, JOHNSON STEVEND, FARWIG NINA. Persistence of flower visitors and pollination services of a generalist tree in modified forests. AUSTRAL ECOL 2012. [DOI: 10.1111/j.1442-9993.2012.02417.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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73
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Manoel RO, Alves PF, Dourado CL, Gaino APSC, Freitas MLM, Moraes MLT, Sebbenn AM. Contemporary pollen flow, mating patterns and effective population size inferred from paternity analysis in a small fragmented population of the Neotropical tree Copaifera langsdorffii Desf. (Leguminosae-Caesalpinioideae). CONSERV GENET 2012. [DOI: 10.1007/s10592-011-0311-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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74
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Evaluating the influence of different aspects of habitat fragmentation on mating patterns and pollen dispersal in the bird-pollinatedBanksia sphaerocarpavar.caesia. Mol Ecol 2011; 21:314-28. [DOI: 10.1111/j.1365-294x.2011.05396.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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75
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Hardesty BD, Le Roux JJ, Rocha OJ, Meyer JY, Westcott D, Wieczorek AM. Getting here from there: testing the genetic paradigm underpinning introduction histories and invasion success. DIVERS DISTRIB 2011. [DOI: 10.1111/j.1472-4642.2011.00832.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022] Open
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76
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Wang R, Compton SG, Chen XY. Fragmentation can increase spatial genetic structure without decreasing pollen-mediated gene flow in a wind-pollinated tree. Mol Ecol 2011; 20:4421-32. [PMID: 21981067 DOI: 10.1111/j.1365-294x.2011.05293.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fragmentation reduces population sizes, increases isolation between habitats and can result in restricted dispersal of pollen and seeds. Given that diploid seed dispersal contributes more to shaping fine-scale spatial genetic structure (SGS) than haploid pollen flow, we tested whether fine-scale SGS can be sensitive to fragmentation even if extensive pollen dispersal is maintained. Castanopsis sclerophylla (Lindley & Paxton) Schottky (Fagaceae), a wind-pollinated and gravity seed-dispersed tree, was studied in an area of southeast China where its populations have been fragmented to varying extents by human activity. Using different age classes of trees in areas subject to varying extents of fragmentation, we found no significant difference in genetic diversity between prefragmentation vs. postfragmentation C. sclerophylla subpopulations. Genetic differentiation among postfragmentation subpopulations was also only slightly lower than among prefragmentation subpopulations. In the most fragmented habitat, selfing rates were significantly higher than zero in prefragmentation, but not postfragmentation, cohorts. These results suggest that fragmentation had not decreased gene flow among these populations and that pollen flow remains extensive. However, significantly greater fine-scale SGS was found in postfragmentation subpopulations in the most fragmented habitat, but not in less fragmented habitats. This alteration in SGS reflected more restricted seed dispersal, induced by changes in the physical environments and the prevention of secondary seed dispersal by rodents. An increase in SGS can therefore result from more restricted seed dispersal, even in the face of extensive pollen flow, making it a sensitive indicator of the negative consequences of population fragmentation.
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Affiliation(s)
- Rong Wang
- Tiantong National Observation Station of Forest Ecosystems, Department of Environmental Sciences, East China Normal University, Shanghai 200062, China
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77
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Finger A, Kettle CJ, Kaiser-Bunbury CN, Valentin T, Doudee D, Matatiken D, Ghazoul J. Back from the brink: potential for genetic rescue in a critically endangered tree. Mol Ecol 2011; 20:3773-84. [PMID: 21883581 DOI: 10.1111/j.1365-294x.2011.05228.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Rare plant species are vulnerable to genetic erosion and inbreeding associated with small population size and isolation due to increasing habitat fragmentation. The degree to which these problems undermine population viability remains debated. We explore genetic and reproductive processes in the critically endangered long-lived tropical tree Medusagyne oppositifolia, an endemic to the Seychelles with a naturally patchy distribution. This species is failing to recruit in three of its four populations. We evaluate whether recruitment failure is linked to genetic problems associated with fragmentation, and if genetic rescue can mitigate such problems. Medusagyne oppositifolia comprises 90 extant trees in four populations, with only the largest (78 trees) having successful recruitment. Using 10 microsatellite loci, we demonstrated that genetic diversity is high (H(E) : 0.48-0.63; H(O) : 0.56-0.78) in three populations, with only the smallest population having relatively low diversity (H(E) : 0.26 and H(O) : 0.30). All populations have unique alleles, high genetic differentiation, and significant within population structure. Pollen and seed dispersal distances were mostly less than 100 m. Individuals in small populations were more related than individuals in the large population, thus inbreeding might explain recruitment failure in small populations. Indeed, inter-population pollination crosses from the large donor population to a small recipient population resulted in higher reproductive success relative to within-population crosses. Our study highlights the importance of maintaining gene flow between populations even in species that have naturally patchy distributions. We demonstrate the potential for genetic and ecological rescue to support conservation of plant species with limited gene flow.
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Affiliation(s)
- A Finger
- ETH Zürich, Institute of Terrestrial Ecosystems, Ecosystem Management, CH-8092 Zürich, Switzerland.
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78
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79
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Rajkumar S, Singh SK, Nag A, Ahuja PS. Genetic structure of Indian valerian (Valeriana jatamansi) populations in western Himalaya revealed by AFLP. Biochem Genet 2011; 49:674-81. [PMID: 21681576 DOI: 10.1007/s10528-011-9448-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Accepted: 05/25/2011] [Indexed: 10/18/2022]
Abstract
Valeriana jatamansi Jones is a natural tetraploid species indigenous to the Indian Himalaya. To assess its genetic diversity and population structure, we analyzed six natural populations from the western Himalayan region using amplified fragment length polymorphism. An analysis of molecular variance found that 93% of the genetic variation of V. jatamansi was within populations and 7% among populations. The correlation between genetic and geographic distances (r = 0.14) was not significant. Though the populations are well separated, the lack of distinct genetic variation between populations may be due to either recent rapid fragmentation from a wide and continuous area resulting in genetically similar populations or wide dispersal of seed by wind, since the follicles are feathery. Polyploidy may be the reason for the lack of genetic impoverishment due to fragmentation.
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Affiliation(s)
- Subramani Rajkumar
- Institute of Himalayan Bioresource Technology (CSIR), P.O. Box 6, Palampur, Himachal Pradesh 176 061, India.
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80
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Braga AC, Collevatti RG. Temporal variation in pollen dispersal and breeding structure in a bee-pollinated Neotropical tree. Heredity (Edinb) 2011; 106:911-9. [PMID: 20978531 PMCID: PMC3186249 DOI: 10.1038/hdy.2010.134] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 09/21/2010] [Indexed: 11/08/2022] Open
Abstract
Variation among flowering seasons in the time of flowering, synchrony and length of flowering, and fluctuations in the abundance of pollinators may cause a variation in pollen dispersal distance. In this study, we analyzed the temporal variation in pollen dispersal and breeding structure in the Neotropical tree species Tabebuia aurea (Bignoniaceae) and evaluated pollen dispersal between a population inside the reserve and a patch of isolated individuals on the edge of the reserve, and tested the hypothesis that isolated individuals are sinking for pollen. All adult trees (260) within a population of 40 ha and 9 isolated individuals on the edge of the reserve were sampled, and from these adults, 21 open-pollinated progeny arrays were analyzed in 2 flowering seasons (309 seeds in 2004 and 328 in 2005). Genetic analyses were based on the polymorphism at 10 microsatellite loci. A high proportion of self-pollination found in both flowering seasons indicated a mixed-mating system. The mean pollen dispersal distance differed significantly between the two flowering seasons (307.78 m in 2004 and 396.26 m in 2005). Maximum pollen dispersal was 2608 m, but most pollination events (65%) occurred at distances <300 m. Our results also showed that isolated individuals are sinking for pollen, with high pollen flow between the population inside the reserve and individuals on the edge. These results are most likely due to the large pollinator species, which can potentially fly long distances, and also due to temporal variation in individual fecundity and contribution to pollen dispersal.
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Affiliation(s)
- A C Braga
- Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, Brazil
| | - R G Collevatti
- Laboratório de Genética e Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
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81
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Field DL, Ayre DJ, Whelan RJ, Young AG. The importance of pre-mating barriers and the local demographic context for contemporary mating patterns in hybrid zones of Eucalyptus aggregata and Eucalyptus rubida. Mol Ecol 2011; 20:2367-79. [PMID: 21375638 DOI: 10.1111/j.1365-294x.2011.05054.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The frequency of hybridization in plants is context dependent and can be influenced by the local mating environment. We used progeny arrays and admixture and pollen dispersal analyses to assess the relative importance of pre-mating reproductive barriers and the local demographic environment as explanations of variation in hybrid frequency in three mapped hybrid zones of Eucalyptus aggregata and E. rubida. A total of 731 open-pollinated progeny from 36 E. aggregata maternal parents were genotyped using six microsatellite markers. Admixture analysis identified substantial variation in hybrid frequency among progeny arrays (0-76.9%). In one hybrid zone, hybrid frequency was related to pre-mating barriers (degree of flowering synchrony) and demographic components of the local mating environment (decreasing population size, closer proximity to E. rubida and hybrid trees). At this site, average pollen dispersal distance was less and almost half (46%) of the hybrid progeny were sired by local E. rubida and hybrid trees. In contrast, at the other two sites, pre-mating and demographic factors were not related to hybrid frequency. Compared to the first hybrid zone where most of the E. rubida (76%) and all hybrids flowered, in the remaining sites fewer E. rubida (22-41%) and hybrid trees (0-50%) flowered and their reproductive success was lower (sired 0-23% of hybrids). As a result, most hybrids were sired by external E. rubida/hybrids located at least 2-3 km away. These results indicate that although pre-mating barriers and local demography can influence patterns of hybridization, their importance can depend upon the scale of pollen dispersal.
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Affiliation(s)
- David L Field
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2, Canada.
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82
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Takakura KI, Matsumoto T, Nishida T, Nishida S. Effective range of reproductive interference exerted by an alien dandelion, Taraxacum officinale, on a native congener. JOURNAL OF PLANT RESEARCH 2011; 124:269-276. [PMID: 20676914 DOI: 10.1007/s10265-010-0368-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Accepted: 06/28/2010] [Indexed: 05/29/2023]
Abstract
Reproductive interference (RI), defined as the fitness cost of interspecific sexual interactions, such as interspecific pollen transfer (IPT) in plants, is ecologically important. Theoretically, RI could result in competitive exclusion, as it operates in a frequency-dependent manner. Additionally, IPT may have a greater range than resource competition, although information about the range of IPT is lacking. In the present study, we measured the range of IPT exerted by Taraxacum officinale (an alien species) on a native dandelion, T. japonicum. We used two approaches. In one, we analyzed the RI effect on a native seed set at three spatial scales. In the second, we tracked IPT from alien to native flower heads using fluorescent pigments as markers. We estimated that pollination distances were in the order of several meters. These distances exceeded the mean distance from each native plant to the nearest alien. As hypothesized, the effect of RI reached farther than neighboring individuals. These data indicate the spatial range from which alien dandelions should be removed to allow the conservation of natives.
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Affiliation(s)
- Koh-Ichi Takakura
- Osaka City Institute of Public Health and Environmental Sciences, 8-34 Tojo-cho, Tennoji-ku, Osaka 543-0026, Japan.
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83
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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.
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Affiliation(s)
- Chris J Kettle
- Ecosystem Management, Institute of Terrestrial Ecosystems, ETH Zurich, Zurich, Switzerland.
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84
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Abe H, Ueno S, Tsumura Y, Hasegawa M. Expanded Home Range of Pollinator Birds Facilitates Greater Pollen Flow of Camellia japonica in a Forest Heavily Damaged by Volcanic Activity. ECOLOGICAL RESEARCH MONOGRAPHS 2011. [DOI: 10.1007/978-4-431-53901-8_5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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85
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Millar MA, Byrne M, Nuberg IK, Sedgley M. High Levels of Genetic Contamination in Remnant Populations of Acacia saligna from a Genetically Divergent Planted Stand. Restor Ecol 2010. [DOI: 10.1111/j.1526-100x.2010.00758.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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86
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Craft KJ, Ashley MV. Pollen-mediated gene flow in isolated and continuous stands of bur oak, Quercus macrocarpa (Fagaceae). AMERICAN JOURNAL OF BOTANY 2010; 97:1999-2006. [PMID: 21616847 DOI: 10.3732/ajb.0900390] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
PREMISE OF THE STUDY Pollination patterns determine the reproductive neighborhood size of plants, the connectivity of populations, and the impacts of habitat fragmentation. We characterized pollination in three populations of Quercus macrocarpa occurring in a highly altered landscape in northeastern Illinois to determine whether isolated remnant stands were reproductively isolated. • METHODS We used microsatellites to genotype all adults and 787 acorns from two isolated savanna remnants and a stand in an old-growth forest. One isolated remnant occurred in a highly urbanized/industrialized landscape, and one occurred in an agricultural landscape. Parentage assignment was used to assess pollen-mediated gene flow. • KEY RESULTS Pollen donors from outside the study sites accounted for between 46% and 53% of paternities and did not differ significantly among sites, indicating that similar high levels of gene flow occurred at all three sites. Within stands, the mean pollination distance ranged from 42 to 70 meters, and when accounting for outside pollinations, mean pollination distances were well over 100 meters. Genetic diversity of incoming pollen was extremely high in all three stands. The number of effective pollen donors, N(ep), calculated from paternity assignment was higher than that estimated by an indirect correlated paternity approach. • CONCLUSIONS Our findings indicate that extremely isolated stands of oaks are unlikely to be genetically and reproductively isolated, and remnant stands may contribute to maintaining genetic connectivity in highly modified landscapes.
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Affiliation(s)
- Kathleen J Craft
- Department of Biological Sciences, 845 W. Taylor St., M/C 066, University of Illinois at Chicago, Chicago, Illinois 60607 USA
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87
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Ndiade-Bourobou D, Hardy OJ, Favreau B, Moussavou H, Nzengue E, Mignot A, Bouvet JM. Long-distance seed and pollen dispersal inferred from spatial genetic structure in the very low-density rainforest tree, Baillonella toxisperma Pierre, in Central Africa. Mol Ecol 2010; 19:4949-62. [PMID: 20964756 DOI: 10.1111/j.1365-294x.2010.04864.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We analysed the spatial distribution of genetic diversity to infer gene flow for Baillonella toxisperma Pierre (Moabi), a threatened entomophilous pollinated and animal-dispersed Central African tree, with typically low density (5-7 adults trees/km(2)). Fifteen nuclear and three universal chloroplast microsatellites markers were used to type 247 individuals localized in three contiguous areas with differing past logging intensity. These three areas were within a natural forest block of approximately 2886 km(2) in Gabon. Expected heterozygosity and chloroplast diversity were He(nuc) = 0.570 and H(cp) = 0.761, respectively. F(IS) was only significant in one area (F(IS) = 0.076, P < 0.01) and could be attributed to selfing. For nuclear loci, Bayesian clustering did not detect discrete gene pools within and between the three areas and global differentiation (F(STnuc) = 0.007, P > 0.05) was not significant, suggesting that they are one population. At the level of the whole forest, both nuclear and chloroplast markers revealed a weak correlation between genetic relatedness and spatial distance between individuals: Sp(nuc) = 0.003 and Sp(cp) = 0.015, respectively. The extent of gene flow (σ) was partitioned into global gene flow (σ(g)) from 6.6 to 9.9 km, seed dispersal (σ(s)) from 4.0 to 6.3 km and pollen dispersal (σ(p)) from 9.8 to 10.8 km. These uncommonly high dispersal distances indicate that low-density canopy trees in African rainforests could be connected by extensive gene flow, although, given the current threats facing many seed disperser species in Central Africa, this may no longer be the case.
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Affiliation(s)
- D Ndiade-Bourobou
- CENAREST, Institut de Recherches Agronomiques et Forestières, BP 842 Gros-bouquet, Libreville, Gabon.
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WILSON ERINE, SIDHU CSHEENA, LeVAN KATHERINEE, HOLWAY DAVIDA. Pollen foraging behaviour of solitary Hawaiian bees revealed through molecular pollen analysis. Mol Ecol 2010; 19:4823-9. [PMID: 20958818 DOI: 10.1111/j.1365-294x.2010.04849.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- ERIN E. WILSON
- Division of Biological Sciences, University of California, San Diego, 9500 Gilman Drive, Mail Code 0116, La Jolla, CA 92093, USA
| | - C. SHEENA SIDHU
- Department of Entomology, The Pennsylvania State University, 501 Agricultural Sciences and Industries Building, University Park, PA 16802, USA
| | - KATHERINE E. LeVAN
- Division of Biological Sciences, University of California, San Diego, 9500 Gilman Drive, Mail Code 0116, La Jolla, CA 92093, USA
| | - DAVID A. HOLWAY
- Division of Biological Sciences, University of California, San Diego, 9500 Gilman Drive, Mail Code 0116, La Jolla, CA 92093, USA
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89
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Gaino APSC, Silva AM, Moraes MA, Alves PF, Moraes MLT, Freitas MLM, Sebbenn AM. Understanding the effects of isolation on seed and pollen flow, spatial genetic structure and effective population size of the dioecious tropical tree species Myracrodruon urundeuva. CONSERV GENET 2010. [DOI: 10.1007/s10592-010-0046-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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90
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Mating system and pollen flow between remnant populations of the endangered tropical tree, Guaiacum sanctum (Zygophyllaceae). CONSERV GENET 2010. [DOI: 10.1007/s10592-010-0130-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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91
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Moraes MLTD, Sebbenn AM. Pollen Dispersal Between Isolated Trees in the Brazilian Savannah: A Case Study of the Neotropical Tree Hymenaea stigonocarpa. Biotropica 2010. [DOI: 10.1111/j.1744-7429.2010.00679.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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92
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Native bees mediate long-distance pollen dispersal in a shade coffee landscape mosaic. Proc Natl Acad Sci U S A 2010; 107:13760-4. [PMID: 20660738 DOI: 10.1073/pnas.1002490107] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Coffee farms are often embedded within a mosaic of agriculture and forest fragments in the world's most biologically diverse tropical regions. Although shade coffee farms can potentially support native pollinator communities, the degree to which these pollinators facilitate gene flow for native trees is unknown. We examined the role of native bees as vectors of gene flow for a reproductively specialized native tree, Miconia affinis, in a shade coffee and remnant forest landscape mosaic. We demonstrate extensive cross-habitat gene flow by native bees, with pollination events spanning more than 1,800 m. Pollen was carried twice as far within shade coffee habitat as in nearby forest, and trees growing within shade coffee farms received pollen from a far greater number of sires than trees within remnant forest. The study shows that shade coffee habitats support specialized native pollinators that enhance the fecundity and genetic diversity of remnant native trees.
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93
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Low levels of realized seed and pollen gene flow and strong spatial genetic structure in a small, isolated and fragmented population of the tropical tree Copaifera langsdorffii Desf. Heredity (Edinb) 2010; 106:134-45. [PMID: 20372183 DOI: 10.1038/hdy.2010.33] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Over the past century, the Brazilian Atlantic forest has been reduced to small, isolated fragments of forest. Reproductive isolation theories predict a loss of genetic diversity and increases in inbreeding and spatial genetic structure (SGS) in such populations. We analysed eight microsatellite loci to investigate the pollen and seed dispersal patterns, genetic diversity, inbreeding and SGS of the tropical tree Copaifera langsdorffii in a small (4.8 ha), isolated population. All 112 adult trees and 128 seedlings found in the stand were sampled, mapped and genotyped. Seedlings had significantly lower levels of genetic diversity (A=16.5±0.45, mean±95% s.e.; H(e)=0.838±0.006) than did adult trees (A=23.2±0.81; H(e)=0.893±0.030). Parentage analysis did not indicate any seed immigration (m(seeds)=0) and the pollen immigration rate was very low (m(pollen)=0.047). The average distance of realized pollen dispersal within the stand was 94 m, with 81% of the pollen travelling <150 m. A significant negative correlation was found between the frequency and distance of pollen dispersal (r=-0.79, P<0.01), indicating that short-distance pollinations were more frequent. A significant SGS for both adults (∼50 m) and seedlings (∼20 m) was also found, indicating that most of the seeds were dispersed over short distances. The results suggested that the spatial isolation of populations by habitat fragmentation can restrict seed and pollen gene flow, increase SGS and affect the genetic diversity of future generations.
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94
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Wagenius S, Hangelbroek HH, Ridley CE, Shaw RG. BIPARENTAL INBREEDING AND INTERREMNANT MATING IN A PERENNIAL PRAIRIE PLANT: FITNESS CONSEQUENCES FOR PROGENY IN THEIR FIRST EIGHT YEARS. Evolution 2010; 64:761-71. [PMID: 19817853 DOI: 10.1111/j.1558-5646.2009.00860.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Stuart Wagenius
- Division of Plant Science and Conservation, Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, Illinois 60022, USA.
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95
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Tarazi R, Moreno MA, Gandara FB, Ferraz EM, Moraes MLT, Vinson CC, Ciampi AY, Vencovsky R, Kageyama PY. High levels of genetic differentiation and selfing in the Brazilian cerrado fruit tree Dipteryx alata Vog. (Fabaceae). Genet Mol Biol 2010; 33:78-85. [PMID: 21637609 PMCID: PMC3036066 DOI: 10.1590/s1415-47572010005000007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Accepted: 07/01/2009] [Indexed: 11/21/2022] Open
Abstract
Dipteryx alata is a native fruit tree species of the cerrado (Brazilian savanna) that has great economic potential because of its multiple uses. Knowledge of how the genetic variability of this species is organized within and among populations would be useful for genetic conservation and breeding programs. We used nine simple sequence repeat (SSR) primers developed for Dipteryx odorata to evaluate the genetic structure of three populations of D. alata located in central Brazil based on a leaf sample analysis from 101 adults. The outcrossing rate was evaluated using 300 open-pollinated offspring from 25 seed-trees. Pollen dispersal was measured by parentage analysis. We used spatial genetic structure (SGS) to test the minimal distance for harvesting seeds in conservation and breeding programs. Our data indicate that the populations studied had a high degree of genetic diversity
and population structure, as suggested by the high level of divergence among populations
. The estimated outcrossing rate
suggested a mixed mating system, and the intrapopulation fixation index was influenced by SGS. We conclude that seed harvesting for genetic conservation and breeding programs requires a minimum distance between trees of 196 m to avoid collecting seeds from related seed-trees.
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Affiliation(s)
- Roberto Tarazi
- Laboratório de Reprodução e Genética de Espécies Arbóreas, Departamento de Ciências Florestais, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP Brazil
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96
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Fuchs EJ, Hamrick JL. Genetic Diversity in the Endangered Tropical Tree, Guaiacum sanctum (Zygophyllaceae). J Hered 2010; 101:284-91. [DOI: 10.1093/jhered/esp127] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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97
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Bird diversity and seed dispersal along a human land-use gradient: high seed removal in structurally simple farmland. Oecologia 2010; 162:965-76. [DOI: 10.1007/s00442-009-1547-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Accepted: 12/09/2009] [Indexed: 10/20/2022]
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98
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Eckert CG, Kalisz S, Geber MA, Sargent R, Elle E, Cheptou PO, Goodwillie C, Johnston MO, Kelly JK, Moeller DA, Porcher E, Ree RH, Vallejo-Marín M, Winn AA. Plant mating systems in a changing world. Trends Ecol Evol 2010; 25:35-43. [PMID: 19683360 DOI: 10.1016/j.tree.2009.06.013] [Citation(s) in RCA: 286] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 06/15/2009] [Accepted: 06/23/2009] [Indexed: 11/19/2022]
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99
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Restricted pollen flow of Dieffenbachia seguine populations in fragmented and continuous tropical forest. Heredity (Edinb) 2009; 105:197-204. [PMID: 20029453 DOI: 10.1038/hdy.2009.179] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Habitat fragmentation can change the ecological context of populations, rupturing genetic connectivity among them, changing genetic structure, and increasing the loss of genetic diversity. We analyzed mating system and pollen structure in two population fragments and two continuous forest populations of Dieffenbachia seguine (Araceae), an insect-pollinated understory herb in the tropical rain forest of Los Tuxtlas, México, using nine allozyme loci. Mating system analysis indicated almost complete outcrossing but some inbreeding among the adults. Pollen structure analysis indicated highly restricted pollen flow, both within and among populations. We showed that the effective pollination neighborhood was small in all populations, and slightly (though not significantly) smaller in fragments, partially as a consequence of an increase in density of reproductive individuals in those fragments. Using assignment analysis, we showed that all populations were strongly structured, suggesting that pollen and seed flow across the Los Tuxtlas landscape has been spatially restricted, though sufficient to maintain connectedness. Forest fragmentation at Los Tuxtlas has (so far) had limited impact on pollen dynamics, despite the changing ecological context, with reduced pollinator abundance being partially offset by increased flowering density in fragments. Continued outcrossing and limited pollen immigration, coupled with more extensive seed migration, should maintain genetic connectedness in D. seguine, if fragmentation is not further exacerbated by additional deforestation.
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100
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Wind-borne insects mediate directional pollen transfer between desert fig trees 160 kilometers apart. Proc Natl Acad Sci U S A 2009; 106:20342-7. [PMID: 19910534 DOI: 10.1073/pnas.0902213106] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The question of how far pollen can move between plants has implications for topics as diverse as habitat fragmentation, conservation management, and the containment of genetically modified crops. The monoecious African fig tree Ficus sycomorus L. relies on the small, short-lived, night-flying, host-specific fig wasp Ceratosolen arabicus Mayr for pollination. We used microsatellite markers to characterize a geographically isolated riparian population of F. sycomorus growing along the Ugab River in the Namib Desert, Namibia, together with paternity analysis of seedlings from known mothers, to map pollen movement within this population. In this way we tracked insect movements between individually recognizable trees by means of their pollen cargo and documented the movement of C. arabicus between known trees separated by more than 160 km, with a mean distance for confirmed successful pollination events of 88.6 km. The predominant observed movement of pollinators was in a westerly direction, toward the sea, reflecting seasonal nighttime wind direction and the wind-borne dispersal of fig wasps. Our results suggest the existence of an extensive panmictic population of trees that are well suited to overcome the effects of geographical isolation.
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