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Valverde J, Medrano M, Herrera CM, Alonso C. Comparative epigenetic and genetic spatial structure in Mediterranean mountain plants: a multispecies study. Heredity (Edinb) 2024; 132:106-116. [PMID: 38233486 PMCID: PMC10844209 DOI: 10.1038/s41437-024-00668-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 12/26/2023] [Accepted: 01/03/2024] [Indexed: 01/19/2024] Open
Abstract
Changes in epigenetic states can allow individuals to cope with environmental changes. If such changes are heritable, this may lead to epigenetic adaptation. Thus, it is likely that in sessile organisms such as plants, part of the spatial epigenetic variation found across individuals will reflect the environmental heterogeneity within populations. The departure of the spatial epigenetic structure from the baseline genetic variation can help in understanding the value of epigenetic regulation in species with different breadth of optimal environmental requirements. Here, we hypothesise that in plants with narrow environmental requirements, epigenetic variability should be less structured in space given the lower variability in suitable environmental conditions. We performed a multispecies study that considered seven pairs of congeneric plant species, each encompassing a narrow endemic with habitat specialisation and a widespread species. In three populations per species we used AFLP and methylation-sensitive AFLP markers to characterise the spatial genetic and epigenetic structures. Narrow endemics showed a significantly lower epigenetic than genetic differentiation between populations. Within populations, epigenetic variation was less spatially structured than genetic variation, mainly in narrow endemics. In these species, structural equation models revealed that such pattern was associated to a lack of correlation between epigenetic and genetic information. Altogether, these results show a greater decoupling of the spatial epigenetic variation from the baseline spatial genetic pattern in endemic species. These findings highlight the value of studying genetic and epigenetic spatial variation to better understand habitat specialisation in plants.
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Affiliation(s)
- Javier Valverde
- Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain.
- Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Sevilla, Spain.
| | - Mónica Medrano
- Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain
| | - Carlos M Herrera
- Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain
| | - Conchita Alonso
- Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain.
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2
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Isla J, Jácome-Flores M, Arroyo JM, Jordano P. The turnover of plant-frugivore interactions along plant range expansion: consequences for natural colonization processes. Proc Biol Sci 2023; 290:20222547. [PMID: 37221844 PMCID: PMC10206477 DOI: 10.1098/rspb.2022.2547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 04/25/2023] [Indexed: 05/25/2023] Open
Abstract
Plant-animal mutualisms such as seed dispersal are key interactions for sustaining plant range shifts. It remains elusive whether the organization of interactions with seed dispersers is reconfigured along the expansion landscape template and, if so, whether its effects accelerate or slow colonization. Here we analyse plant-frugivore interactions in a scenario of rapid population expansion of a Mediterranean juniper. We combined network analyses with field surveys, sampling interactions between individual plants and frugivores by DNA-barcoding and phototrapping over two seasons. We assess the role of intrinsic and extrinsic intraspecific variability in shaping interactions and we estimate the individual plant contributions to the seed rain. The whole interaction network was highly structured, with a distinct set of modules including individual plants and frugivore species arranged concordantly along the expansion gradient. The modular configuration was partially shaped by individual neighbourhood context (density and fecundity) and phenotypic traits (cone size). Interaction reconfiguration resulted in a higher and more uneven propagule contribution, with most effective dispersers having a prominent role at the colonization front stand, where a distinct subset of early arriving plants dominated the seed rain. Our study offers new insights into the key role of mutualistic interactions in colonization scenarios by promoting fast plant expansion processes.
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Affiliation(s)
- Jorge Isla
- Estación Biológica de Doñana, CSIC, Av. Americo Vespucio 26, 41092 Sevilla, Spain
| | - Miguel Jácome-Flores
- Estación Biológica de Doñana, CSIC, Av. Americo Vespucio 26, 41092 Sevilla, Spain
- CONACYT-Centro del Cambio Global y la Sustentabilidad, 86080 Villahermosa, Tabasco, México
| | - Juan M. Arroyo
- Estación Biológica de Doñana, CSIC, Av. Americo Vespucio 26, 41092 Sevilla, Spain
| | - Pedro Jordano
- Estación Biológica de Doñana, CSIC, Av. Americo Vespucio 26, 41092 Sevilla, Spain
- Dept. Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, 41012 Sevilla, Spain
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3
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Lewis EM, Fant JB, Moore MJ, Skogen KA. Hawkmoth and bee pollinators impact pollen dispersal at the landscape but not local scales in two species of Oenothera. AMERICAN JOURNAL OF BOTANY 2023:e16156. [PMID: 36934437 DOI: 10.1002/ajb2.16156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 02/01/2023] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Abstract
PREMISE Animal pollinators play an important role in pollen dispersal. Here, we assessed differences in pollen and seed dispersal and the role of pollinator functional groups with different foraging behaviors in generating patterns of genetic diversity over similar geographic ranges for two closely related taxa. We focused on two members of Oenothera section Calylophus (Onagraceae) that co-occur on gypsum outcrops throughout the northern Chihuahuan Desert but differ in floral phenotype and primary pollinator: Oenothera gayleana (bee) and O. hartwegii subsp. filifolia (hawkmoth). METHODS We measured breeding system and floral traits and studied gene flow and population differentiation at the local (<13 km; four populations) and landscape (60-440 km; five populations) scales using 10-11 nuclear (pollen dispersal) and three plastid (seed dispersal) microsatellite markers. RESULTS Both taxa were self-incompatible and floral traits were consistent with expectations for different pollinators. Seed and pollen dispersal patterns were distinctly different for both species. We found no evidence of genetic structure at the local scale but did at the landscape scale; O. gayleana showed greater differentiation and significant isolation by distance than in O. hartwegii subsp. filifolia. The plastid data were consistent with gravity dispersal of seeds and suggest that pollen dispersal is the principal driver of genetic structure in both species. CONCLUSIONS We demonstrated that pollinator functional groups can impact genetic differentiation in different and predictable ways. Hawkmoths, with larger foraging distances, can maintain gene flow across greater spatial scales than bees.
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Affiliation(s)
- Emily M Lewis
- Northwestern University, Program in Plant Biology and Conservation, Evanston, IL, 60201, USA
| | - Jeremie B Fant
- Northwestern University, Program in Plant Biology and Conservation, Evanston, IL, 60201, USA
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, Glencoe, IL, 60022, USA
| | - Michael J Moore
- Biology Department, Oberlin College, Oberlin, OH, 44074, USA
| | - Krissa A Skogen
- Northwestern University, Program in Plant Biology and Conservation, Evanston, IL, 60201, USA
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, Glencoe, IL, 60022, USA
- Department of Biological Sciences, Clemson University, Clemson, SC, 29634, USA
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4
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Chung MY, Merilä J, Li J, Mao K, López-Pujol J, Tsumura Y, Chung MG. Neutral and adaptive genetic diversity in plants: An overview. Front Ecol Evol 2023. [DOI: 10.3389/fevo.2023.1116814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
Genetic diversity is a prerequisite for evolutionary change in all kinds of organisms. It is generally acknowledged that populations lacking genetic variation are unable to evolve in response to new environmental conditions (e.g., climate change) and thus may face an increased risk of extinction. Although the importance of incorporating genetic diversity into the design of conservation measures is now well understood, less attention has been paid to the distinction between neutral (NGV) and adaptive (AGV) genetic variation. In this review, we first focus on the utility of NGV by examining the ways to quantify it, reviewing applications of NGV to infer ecological and evolutionary processes, and by exploring its utility in designing conservation measures for plant populations and species. Against this background, we then summarize the ways to identify and estimate AGV and discuss its potential use in plant conservation. After comparing NGV and AGV and considering their pros and cons in a conservation context, we conclude that there is an urgent need for a better understanding of AGV and its role in climate change adaptation. To date, however, there are only a few AGV studies on non-model plant species aimed at deciphering the genetic and genomic basis of complex trait variation. Therefore, conservation researchers and practitioners should keep utilizing NGV to develop relevant strategies for rare and endangered plant species until more estimates of AGV are available.
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5
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Trapnell DW, Hamrick JL. Genetic inference of orchid population dynamics on different‐aged lava flows in Costa Rica. Biotropica 2022. [DOI: 10.1111/btp.13163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Krach EK, Skaro M, Wu Y, Arnold J. Characterizing the gene-environment interaction underlying natural morphological variation in Neurospora crassa conidiophores using high-throughput phenomics and transcriptomics. G3 (BETHESDA, MD.) 2022; 12:jkac050. [PMID: 35293585 PMCID: PMC8982394 DOI: 10.1093/g3journal/jkac050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 02/21/2022] [Indexed: 11/12/2022]
Abstract
Neurospora crassa propagates through dissemination of conidia, which develop through specialized structures called conidiophores. Recent work has identified striking variation in conidiophore morphology, using a wild population collection from Louisiana, United States of America to classify 3 distinct phenotypes: Wild-Type, Wrap, and Bulky. Little is known about the impact of these phenotypes on sporulation or germination later in the N. crassa life cycle, or about the genetic variation that underlies them. In this study, we show that conidiophore morphology likely affects colonization capacity of wild N. crassa isolates through both sporulation distance and germination on different carbon sources. We generated and crossed homokaryotic strains belonging to each phenotypic group to more robustly fit a model for and estimate heritability of the complex trait, conidiophore architecture. Our fitted model suggests at least 3 genes and 2 epistatic interactions contribute to conidiophore phenotype, which has an estimated heritability of 0.47. To uncover genes contributing to these phenotypes, we performed RNA-sequencing on mycelia and conidiophores of strains representing each of the 3 phenotypes. Our results show that the Bulky strain had a distinct transcriptional profile from that of Wild-Type and Wrap, exhibiting differential expression patterns in clock-controlled genes (ccgs), the conidiation-specific gene con-6, and genes implicated in metabolism and communication. Combined, these results present novel ecological impacts of and differential gene expression underlying natural conidiophore morphological variation, a complex trait that has not yet been thoroughly explored.
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Affiliation(s)
- Emily K Krach
- Genetics Department, University of Georgia, Athens, GA 30602, USA
| | - Michael Skaro
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
| | - Yue Wu
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
| | - Jonathan Arnold
- Genetics Department, University of Georgia, Athens, GA 30602, USA
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
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7
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Cheplick GP. Philomatry in plants: why do so many species have limited seed dispersal? AMERICAN JOURNAL OF BOTANY 2022; 109:29-45. [PMID: 34679185 DOI: 10.1002/ajb2.1791] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 10/14/2021] [Accepted: 10/18/2021] [Indexed: 06/13/2023]
Abstract
Many have noted limited seed dispersal of plants in diverse environments and attempted evolutionary explanations for it. Although philopatric ("love of fatherland") is used by zoologists to describe organisms that remain near their place of origin, philomatric ("love of motherland") is proposed as more appropriate for plants because seeds develop on the maternal parent, fecundity and dispersal are maternally influenced characteristics, and the term dovetails with the mother-site hypothesis (MSH) for the evolution of restricted dispersal. Proximate reasons for philomatry include intrinsic drivers such as morphological features of diaspores and where on the maternal parent they are produced. Extrinsic drivers include local environmental conditions, surrounding vegetation, and ineffective dispersal agents. The MSH proposes that selection should favor philomatry in a population adapted to a particular habitat because offspring will likewise be adapted to that same habitat. Several studies show philomatry can mitigate distance-dependent costs of dispersing into surrounding inhospitable areas. Undispersed diaspores can eliminate energetic costs of accessory structures or biochemicals needed by dispersible diaspores, but it is unclear whether these costs are significant to the evolution of philomatry. Disadvantages of limited dispersal are inability to escape deteriorating habitat conditions, inability to colonize new habitats, and inbreeding among offspring. Heterocarpic species offset these disadvantages by producing dispersed plus undispersed diaspores. A conceptual framework is presented relating dispersal distance to the probability of seedling establishment. Future research should recognize dispersal as a covarying syndrome of multiple life history traits and focus on ecological selection agents that favor philomatry.
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Affiliation(s)
- Gregory P Cheplick
- Biology Program, Plant Science Subprogram, The Graduate Center, City University of New York, New York, NY, 10016, USA
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8
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Chaves CJN, Leal BSS, Rossatto DR, Berger U, Palma-Silva C. Deforestation is the turning point for the spreading of a weedy epiphyte: an IBM approach. Sci Rep 2021; 11:20397. [PMID: 34650134 PMCID: PMC8516858 DOI: 10.1038/s41598-021-99798-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 09/27/2021] [Indexed: 11/08/2022] Open
Abstract
The rapid spread of many weeds into intensely disturbed landscapes is boosted by clonal growth and self-fertilization strategies, which conversely increases the genetic structure of populations. Here, we use empirical and modeling approaches to evaluate the spreading dynamics of Tillandsia recurvata (L.) L. populations, a common epiphytic weed with self-reproduction and clonal growth widespread in dry forests and deforested landscapes in the American continent. We introduce the TRec model, an individual-based approach to simulate the spreading of T. recurvata over time and across landscapes subjected to abrupt changes in tree density with the parameters adjusted according to the empirical genetic data based on microsatellites genotypes. Simulations with this model showed that the strong spatial genetic structure observed from empirical data in T. recurvata can be explained by a rapid increase in abundance and gene flow followed by stabilization after ca. 25 years. TRec model's results also indicate that deforestation is a turning point for the rapid increase in both individual abundance and gene flow among T. recurvata subpopulations occurring in formerly dense forests. Active reforestation can, in turn, reverse such a scenario, although with a milder intensity. The genetic-based study suggests that anthropogenic changes in landscapes may strongly affect the population dynamics of species with 'weedy' traits.
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Affiliation(s)
- Cleber Juliano Neves Chaves
- Programa de Pós-Graduação em Ecologia e Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, 13506-900, Brazil.
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, 13083-862, Brazil.
| | - Bárbara Simões Santos Leal
- Programa de Pós-Graduação em Ecologia e Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, 13506-900, Brazil
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, 13083-862, Brazil
| | - Davi Rodrigo Rossatto
- Departamento de Biologia, Universidade Estadual Paulista, Jaboticabal, 14884-900, Brazil
| | - Uta Berger
- Institute of Forest Growth and Computer Sciences, Technische Universität Dresden, 01737, Tharandt, Germany
| | - Clarisse Palma-Silva
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, 13083-862, Brazil
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9
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Hedrén M, Birkedal S, de Boer H, Ghorbani A, Gravendeel B, Hansson S, Svensson Å, Zarre S. Asymmetric contributions of seed and pollen to gene dispersal in the marsh orchid Dactylorhiza umbrosa in Asia Minor. Mol Ecol 2021; 30:1791-1805. [PMID: 33587812 DOI: 10.1111/mec.15848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 07/25/2020] [Accepted: 08/05/2020] [Indexed: 11/29/2022]
Abstract
Orchids differ from other plants in their extremely small and partly air-filled seeds that can be transported long distances by wind. Seed dispersal in orchids is expected to contribute strongly to overall gene flow, and orchids generally express low levels of genetic differentiation between populations and low pollen to seed flow ratios. However, studies in orchids distributed in northern Europe have often found a poor geographic structuring of genetic variation. Here, we studied geographic differentiation in the marsh orchid Dactylorhiza umbrosa, which is widely distributed in upland regions from Asia Minor to Central Asia. These areas were less affected by Pleistocene ice ages than northern Europe and the orchid should have been able to survive the last ice age in local refugia. In the plastid genome, which is dispersed by seeds, populations at close distance were clearly divergent, but the differentiation still increased with geographic distance, and a significant phylogeographic structure had developed. In the nuclear genome, which is dispersed by both seeds and pollen, populations showed an even stronger correlation between genetic and geographic distance, but average levels of differentiation were lower than in the plastid genome, and no phylogeographic structure was evident. Combining plastid and nuclear data, we found that the ratio of pollen to seed dispersal (mp/ms) decreases with physical distance. Comparison with orchids that grow in parts of Europe that were glaciated during the last ice suggests that a balanced structure of genetic diversity develops only slowly in many terrestrial orchids, despite efficient seed dispersal.
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Affiliation(s)
- Mikael Hedrén
- Department of Biology, University of Lund, Lund, Sweden
| | | | - Hugo de Boer
- Natural History Museum, University of Oslo, Oslo, Norway.,Department of Organismal Biology, Uppsala University, Uppsala, Sweden.,Endless Forms Group, Naturalis Biodiversity Center, Leiden, The Netherlands
| | | | - Barbara Gravendeel
- Endless Forms Group, Naturalis Biodiversity Center, Leiden, The Netherlands
| | | | - Åke Svensson
- Department of Dermatology, Malmö University Hospital SUS, Malmö, Sweden
| | - Shahin Zarre
- Department of Plant Sciences, School of Biology, College of Science, University of Tehran, Tehran, Iran
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10
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Gamba D, Muchhala N. Global patterns of population genetic differentiation in seed plants. Mol Ecol 2020; 29:3413-3428. [PMID: 32743850 DOI: 10.1111/mec.15575] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 06/06/2020] [Accepted: 07/23/2020] [Indexed: 01/07/2023]
Abstract
Evaluating the factors that drive patterns of population differentiation in plants is critical for understanding several biological processes such as local adaptation and incipient speciation. Previous studies have given conflicting results regarding the significance of pollination mode, seed dispersal mode, mating system, growth form and latitudinal region in shaping patterns of genetic structure, as estimated by FST values, and no study to date has tested their relative importance together across a broad scale. Here, we assembled a 337-species data set for seed plants from publications with data on FST from nuclear markers and species traits, including variables pertaining to the sampling scheme of each study. We used species traits, while accounting for sampling variables, to perform phylogenetic multiple regressions. Results demonstrated that FST values were higher for tropical, mixed-mating, non-woody species pollinated by small insects, indicating greater population differentiation, and lower for temperate, outcrossing trees pollinated by wind. Among the factors we tested, latitudinal region explained the largest portion of variance, followed by pollination mode, mating system and growth form, while seed dispersal mode did not significantly relate to FST . Our analyses provide the most robust and comprehensive evaluation to date of the main ecological factors predicted to drive population differentiation in seed plants, with important implications for understanding the basis of their genetic divergence. Our study supports previous findings showing greater population differentiation in tropical regions and is the first that we are aware of to robustly demonstrate greater population differentiation in species pollinated by small insects.
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Affiliation(s)
- Diana Gamba
- Biology Department, University of Missouri, Saint Louis, MO, USA
| | - Nathan Muchhala
- Biology Department, University of Missouri, Saint Louis, MO, USA
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11
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Zhang Z, Gale SW, Li JH, Fischer GA, Ren MX, Song XQ. Pollen-mediated gene flow ensures connectivity among spatially discrete sub-populations of Phalaenopsis pulcherrima, a tropical food-deceptive orchid. BMC PLANT BIOLOGY 2019; 19:597. [PMID: 31888488 PMCID: PMC6937714 DOI: 10.1186/s12870-019-2179-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 11/29/2019] [Indexed: 05/20/2023]
Abstract
BACKGROUND Gene flow in plants via pollen and seeds is asymmetrical at different geographic scales. Orchid seeds are adapted to long-distance wind dispersal but pollinium transfer is often influenced by pollinator behavior. We combined field studies with an analysis of genetic diversity among 155 physically mapped adults and 1105 F1 seedlings to evaluate the relative contribution of pollen and seed dispersal to overall gene flow among three sub-populations of the food-deceptive orchid Phalaenopsis pulcherrima on Hainan Island, China. RESULTS Phalaenopsis pulcherrima is self-sterile and predominantly outcrossing, resulting in high population-level genetic diversity, but plants are clumped and exhibit fine-scale genetic structuring. Even so, we detected low differentiation among sub-populations, with polynomial regression analysis suggesting gene flow via seed to be more restricted than that via pollen. Paternity analysis confirmed capsules of P. pulcherrima to each be sired by a single pollen donor, probably in part facilitated by post-pollination stigma obfuscation, with a mean pollen flow distance of 272.7 m. Despite limited sampling, we detected no loss of genetic diversity from one generation to the next. CONCLUSIONS Outcrossing mediated by deceptive pollination and self-sterility promote high genetic diversity in P. pulcherrima. Long-range pollinia transfer ensures connectivity among sub-populations, offsetting the risk of genetic erosion at local scales.
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Affiliation(s)
- Zhe Zhang
- Key Laboratory of Genetics and Germplasm Innovation of Tropical Special Forest Trees and Ornamental Plants (Hainan University), Ministry of Education, College of Forestry, Hainan University, Haikou, People's Republic of China
- Key Laboratory of Germplasm Resources of Tropical Special Ornamental Plants of Hainan Province, College of Forestry, Hainan University, Haikou, People's Republic of China
| | - Stephan W Gale
- Kadoorie Farm & Botanic Garden, Lam Kam Road, Tai Po, Hong Kong, People's Republic of China.
| | - Ji-Hong Li
- Kadoorie Farm & Botanic Garden, Lam Kam Road, Tai Po, Hong Kong, People's Republic of China
| | - Gunter A Fischer
- Kadoorie Farm & Botanic Garden, Lam Kam Road, Tai Po, Hong Kong, People's Republic of China
| | - Ming-Xun Ren
- Key Laboratory of Genetics and Germplasm Innovation of Tropical Special Forest Trees and Ornamental Plants (Hainan University), Ministry of Education, College of Forestry, Hainan University, Haikou, People's Republic of China
- Center for Terrestrial Biodiversity of the South China Sea, Hainan University, Haikou, People's Republic of China
| | - Xi-Qiang Song
- Key Laboratory of Genetics and Germplasm Innovation of Tropical Special Forest Trees and Ornamental Plants (Hainan University), Ministry of Education, College of Forestry, Hainan University, Haikou, People's Republic of China.
- Key Laboratory of Germplasm Resources of Tropical Special Ornamental Plants of Hainan Province, College of Forestry, Hainan University, Haikou, People's Republic of China.
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12
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Trapnell DW, Hamrick JL, Smallwood PA, Kartzinel TR, Ishibashi CD, Quigley CTC. Phylogeography of the Neotropical epiphytic orchid, Brassavola nodosa: evidence for a secondary contact zone in northwestern Costa Rica. Heredity (Edinb) 2019; 123:662-674. [PMID: 31015580 PMCID: PMC6972751 DOI: 10.1038/s41437-019-0218-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 02/13/2019] [Accepted: 03/10/2019] [Indexed: 11/08/2022] Open
Abstract
Spatial patterns of genetic variation can reveal otherwise cryptic evolutionary and landscape processes. In northwestern Costa Rica, an approximately concordant genetic discontinuity occurs among populations of several plant species. We conducted phylogeographic analyses of an epiphytic orchid, Brassavola nodosa, to test for genetic discontinuity and to explore its underlying causes. We genotyped 18 populations with 19 nuclear loci and two non-coding chloroplast sequence regions. We estimated genetic diversity and structure, relative importance of pollen and seed dispersal, and divergence time to understand how genetic diversity was spatially partitioned. Nuclear genetic diversity was high with little differentiation among populations (GSTn = 0.065). In contrast, chloroplast haplotypes were highly structured (GSTc = 0.570) and reveal a discontinuity between northwestern and southeastern populations within Costa Rica. Haplotype differences suggest two formerly isolated lineages that diverged ~10,000-100,000 YBP. Haplotype mixing and greater genetic diversity occur in an intermediate transition zone. Patterns of nuclear and chloroplast data were consistent. Different levels of genetic differentiation for the two genomes reflect the relative effectiveness of biotic versus abiotic dispersers of pollen and seeds, respectively. Isolation of the two lineages likely resulted from the complex environmental and geophysical history of the region. Our results suggest a recent cryptic seed dispersal barrier and/or zone of secondary contact. We hypothesize that powerful northeasterly trade winds hinder movement of wind-borne seeds between the two regions, while the multi-directional dispersal of pollen by strong-flying sphinx moths resulted in lower differentiation of nuclear loci.
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Affiliation(s)
- Dorset W Trapnell
- Department of Plant Biology, University of Georgia, Athens, GA, 30602, USA.
| | - J L Hamrick
- Department of Plant Biology, University of Georgia, Athens, GA, 30602, USA
| | | | - Tyler R Kartzinel
- Odum School of Ecology, University of Georgia, Athens, GA, 30602, USA
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA
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13
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Sujii PS, Cozzolino S, Pinheiro F. Hybridization and geographic distribution shapes the spatial genetic structure of two co-occurring orchid species. Heredity (Edinb) 2019; 123:458-469. [PMID: 31391556 PMCID: PMC6781141 DOI: 10.1038/s41437-019-0254-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/11/2019] [Accepted: 07/17/2019] [Indexed: 11/09/2022] Open
Abstract
Multiple ecological and life-history traits shape the fine-scale spatial genetic structure (FSGS) of a given population. The occurrence in core versus peripheral populations, levels of outcrossing, pollen and seed dispersal, and hybridization are important biological properties that influence the kinship of individuals within populations. We examined spatial genetic structure within 15 populations of Epidendrum fulgens and E. puniceoluteum distributed along a linear gradient of Brazilian coastal vegetation, including both allopatric and sympatric populations where the two orchid species hybridize. We analyzed 581 mapped specimens using nine simple sequence repeat loci, aiming to investigate how geographic distribution and hybridization shape within-population FSGS. A significant increase in FSGS was found towards peripheral populations, compared to core populations. Analysis of short-distance and long-distance components of FSGS identified biparental inbreeding and higher levels of FSGS at peripheral populations, when compared to core populations. In contrast, the relatively high density of reproductive adults in core populations potentially leads to highly overlapping seed and pollen movement, decreasing FSGS. Hybridization was an important factor shaping within-population spatial genetic structure at sympatric sites, decreasing the FSGS observed in parental species. Our results indicate that different ecological forces act in concert to create a gradient of FSGS along species distribution ranges, shaped by extensive levels of intraspecific and interspecific gene exchange.
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Affiliation(s)
| | - Salvatore Cozzolino
- Department of Biology, Complesso Universitario di Monte S. Angelo, Università degli Studi di Napoli Federico II, 80126, Napoli, Italy
| | - Fábio Pinheiro
- Departamento de Biologia Vegetal, Universidade Estadual de Campinas, Instituto de Biologia, Campinas, Brazil.
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14
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Nagamitsu T, Shuri K, Kikuchi S, Koike S, Naoe S, Masaki T. Multiscale spatial genetic structure within and between populations of wild cherry trees in nuclear genotypes and chloroplast haplotypes. Ecol Evol 2019; 9:11266-11276. [PMID: 31641471 PMCID: PMC6802027 DOI: 10.1002/ece3.5628] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 07/31/2019] [Accepted: 08/07/2019] [Indexed: 11/10/2022] Open
Abstract
Spatial genetic structure (SGS) of plants mainly depends on the effective population size and gene dispersal. Maternally inherited loci are expected to have higher genetic differentiation between populations and more intensive SGS within populations than biparentally inherited loci because of smaller effective population sizes and fewer opportunities of gene dispersal in the maternally inherited loci. We investigated biparentally inherited nuclear genotypes and maternally inherited chloroplast haplotypes of microsatellites in 17 tree populations of three wild cherry species under different conditions of tree distribution and seed dispersal. As expected, interpopulation genetic differentiation was 6-9 times higher in chloroplast haplotypes than in nuclear genotypes. This difference indicated that pollen flow 4-7 times exceeded seed flow between populations. However, no difference between nuclear and chloroplast loci was detected in within-population SGS intensity due to their substantial variation among the populations. The SGS intensity tended to increase as trees became more aggregated, suggesting that tree aggregation biased pollen and seed dispersal distances toward shorter. The loss of effective seed dispersers, Asian black bears, did not affect the SGS intensity probably because of mitigation of the bear loss by other vertebrate dispersers and too few tree generations after the bear loss to alter SGS. The findings suggest that SGS is more variable in smaller spatial scales due to various ecological factors in local populations.
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Affiliation(s)
- Teruyoshi Nagamitsu
- Hokkaido Research CenterForestry and Forest Products Research InstituteForest Research and Management OrganizationSapporoJapan
| | - Kato Shuri
- Tama Forest Science GardenForestry and Forest Products Research InstituteForest Research and Management OrganizationHachiojiJapan
| | - Satoshi Kikuchi
- Forestry and Forest Products Research InstituteForest Research and Management OrganizationTsukubaJapan
| | - Shinsuke Koike
- Institute of AgricultureTokyo University of Agriculture and TechnologyFuchuJapan
| | - Shoji Naoe
- Tohoku Research CenterForestry and Forest Products Research InstituteForest Research and Management OrganizationMoriokaJapan
| | - Takashi Masaki
- Forestry and Forest Products Research InstituteForest Research and Management OrganizationTsukubaJapan
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15
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Gelmi‐Candusso TA, Bialozyt R, Slana D, Zárate Gómez R, Heymann EW, Heer K. Estimating seed dispersal distance: A comparison of methods using animal movement and plant genetic data on two primate-dispersed Neotropical plant species. Ecol Evol 2019; 9:8965-8977. [PMID: 31462995 PMCID: PMC6706201 DOI: 10.1002/ece3.5422] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/30/2019] [Accepted: 06/10/2019] [Indexed: 11/29/2022] Open
Abstract
Seed dispersal distance (SDD) critically influences the survival of seedlings, spatial patterns of genetic diversity within plant populations, and gene flow among plant populations. In animal-dispersed species, foraging behavior and movement patterns determine SDD. Direct observations of seed dispersal events by animals in natural plant populations are mostly constrained by the high mobility and low visibility of seed dispersers. Therefore, diverse alternative methods are used to estimate seed dispersal distance, but direct comparisons of these approaches within the same seed dispersal system are mostly missing.We investigated two plant species with different life history traits, Leonia cymosa and Parkia panurensis, exclusively dispersed by two tamarin species, Saguinus mystax and Leontocebus nigrifrons. We compared SDD estimates obtained from direct observations, genetic identification of mother plants from seed coats, parentage analysis of seedlings/saplings, and phenomenological and mechanistic modeling approaches.SDD derived from the different methods ranged between 158 and 201 m for P. panurensis and between 178 and 318 m for L. cymosa. In P. panurensis, the modeling approaches resulted in moderately higher estimates than observations and genotyping of seed coats. In L. cymosa, parentage analysis resulted in a lower estimate than all other methods. Overall, SDD estimates for P. panurensis (179 ± 16 m; mean ± SD) were significantly lower than for L. cymosa (266 ± 59 m; mean ± SD).Differences among methods were related to processes of the seed dispersal loop integrated by the respective methods (e.g., seed deposition or seedling distribution). We discuss the merits and limitations of each method and highlight the aspects to be considered when comparing SDD derived from different methodologies. Differences among plant species were related to differences in reproductive traits influencing gut passage time and feeding behavior, highlighting the importance of plant traits on animal-mediated seed dispersal distance.
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Affiliation(s)
- Tiziana A. Gelmi‐Candusso
- Verhaltensökologie & SoziobiologieDeutsches Primatenzentrum – Leibniz‐Institut für PrimatenforschungGöttingenGermany
| | - Ronald Bialozyt
- Conservation BiologyPhillips‐Universität MarburgMarburgGermany
- Present address:
Nordwestdeutsche Forstliche VersuchsanstaltGöttingenGermany
| | - Darja Slana
- Verhaltensökologie & SoziobiologieDeutsches Primatenzentrum – Leibniz‐Institut für PrimatenforschungGöttingenGermany
| | | | - Eckhard W. Heymann
- Verhaltensökologie & SoziobiologieDeutsches Primatenzentrum – Leibniz‐Institut für PrimatenforschungGöttingenGermany
| | - Katrin Heer
- Conservation BiologyPhillips‐Universität MarburgMarburgGermany
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16
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Hedrén M, Olofsson SN, Paun O. Orchid colonization: multiple parallel dispersal events and mosaic genetic structure in Dactylorhiza majalis ssp. lapponica on the Baltic island of Gotland. ANNALS OF BOTANY 2018; 122:1019-1032. [PMID: 29955767 PMCID: PMC6266126 DOI: 10.1093/aob/mcy111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 05/29/2018] [Indexed: 06/08/2023]
Abstract
Background and Aims The island of Gotland in the Baltic Sea has had no contact with surrounding continental areas since the withdrawal of the Weichselian ice sheet at approx. 17 ka BP. Plants present on Gotland must have arrived by long-distance dispersal, so populations are expected to exhibit reduced levels of genetic diversity compared with populations on surrounding mainlands. However, orchids have very small seeds, which appear well adapted to long-distance dispersal, and they should therefore be less affected than other plant species by colonization bottlenecks. The aim of this study was to analyse the genetic structure of orchids colonizing isolated islands, using the marsh orchid Dactylorhiza majalis ssp. lapponica as a case study. Methods More than 500 samples from 27 populations were analysed for 15 plastid and eight nuclear marker loci. Population diversity and differentiation patterns were compared for nuclear and plastid marker systems and analysed in relation to geographical location. Key Results We found high genetic diversity but no clear geographical structure of genetic differentiation between populations on Gotland. However, the between-population differentiation in plastid and nuclear markers were correlated and the greatest diversity was found at sites at comparatively high elevations, which were the first to emerge above the water after the Ice Age. Conclusions The regional population on Gotland has been established by a minimum of four dispersal events from continental regions. Subsequent gene flow between sites has not yet homogenized the differentiation pattern originating from initial colonization. We conclude that long-distance seed dispersal in orchids has a strong impact on structuring genetic diversity during periods of expansion and colonization, but contributes less to gene flow between populations once a stable population structure has been achieved.
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Affiliation(s)
- Mikael Hedrén
- Department of Biology, University of Lund, Lund, Sweden
| | | | - Ovidiu Paun
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
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17
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Tarszisz E, Tomlinson S, Harrison ME, Morrogh-Bernard HC, Munn AJ. An ecophysiologically informed model of seed dispersal by orangutans: linking animal movement with gut passage across time and space. CONSERVATION PHYSIOLOGY 2018; 6:coy013. [PMID: 29942515 PMCID: PMC6007347 DOI: 10.1093/conphys/coy013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 02/14/2018] [Accepted: 02/23/2018] [Indexed: 05/30/2023]
Abstract
Fauna-mediated ecosystem service provision (e.g. seed dispersal) can be difficult to quantify and predict because it is underpinned by the shifting niches of multiple interacting organisms. Such interactions are especially complex in tropical ecosystems, including endangered peat forests of Central Borneo, a biodiversity hot spot and home to the critically endangered orangutan (Pongo pygmaeus wurmbii). We combined studies of the digestive physiology of captive orangutans in Australia with detailed field studies of wild orangutans in the Natural Laboratory of Peat-Swamp Forest of Sabangau, Central Kalimantan, Indonesia. By measuring the gut transit time (TT) of indigestible seed mimics (beads) in captivity and applying this as a temporal constraint to movement data of wild orangutans, we developed a mechanistic, time-explicit spatial model to project the seed dispersal patterns by these large-bodied, arboreal frugivores. We followed seven orangutans and established home range kernels using Time Local Convex Hull (T-LoCoH) modelling. This allowed us to model individual orangutan movements and to adjust these models according to gut transit times to estimate seed dispersal kernels. Female movements were conservative (core ranges of 55 and 52 ha in the wet and dry seasons, respectively) and revisitation rates to the same location of n = 4 in each 24-h block. Male movements were more unpredictable, yielding fragmented core ranges and revisitation rates to the same location of only 1.2 times each 24 h; males also demonstrated large disjunctions where they moved rapidly over long distances and were frequently lost from view. Seed dispersal kernels were nested predictably within the core ranges of females, but not males. We used the T-LoCoH approach to analyse movement ecology, which offered a powerful tool to predict the primary deposition of seeds by orangutans, thereby providing a reliable method for making a priori predictions of seed dispersal dynamics by other frugivores in novel ecosystems.
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Affiliation(s)
- Esther Tarszisz
- School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia
- Borneo Nature Foundation, Jl. Bukit Raya 82, Palangka Raya 73112, Central Kalimantan, Indonesia
| | - Sean Tomlinson
- School of Molecular & Life Sciences, Curtin University of Technology, Kent Street Bentley, WA 6102, Australia
- Kings Park Science, Department of Biodiversity Conservation and Attractions, Kattidj Close, Kings Park, WA 6005, Australia
| | - Mark E Harrison
- Borneo Nature Foundation, Jl. Bukit Raya 82, Palangka Raya 73112, Central Kalimantan, Indonesia
- School of Geography, Geology and the Environment, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Helen C Morrogh-Bernard
- Borneo Nature Foundation, Jl. Bukit Raya 82, Palangka Raya 73112, Central Kalimantan, Indonesia
- Centre for Ecology & Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Penryn, Cornwall TR10 9EZ, UK
| | - Adam J Munn
- School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia
- School of Biological, Earth and Environmental Sciences, The University of New South Wales, NSW 2052, Australia
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18
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Reiserer RS, Schuett GW, Greene HW. Seed ingestion and germination in rattlesnakes: overlooked agents of rescue and secondary dispersal. Proc Biol Sci 2018; 285:rspb.2017.2755. [PMID: 29436500 DOI: 10.1098/rspb.2017.2755] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Accepted: 01/12/2018] [Indexed: 11/12/2022] Open
Abstract
Seed dispersal is a key evolutionary process and a central theme in the population ecology of terrestrial plants. The primary producers of most land-based ecosystems are propagated by and maintained through various mechanisms of seed dispersal that involve both abiotic and biotic modes of transportation. By far the most common biotic seed transport mechanism is zoochory, whereby seeds, or fruits containing them, are dispersed through the activities of animals. Rodents are one group of mammals that commonly prey on seeds (granivores) and play a critical, often destructive, role in primary dispersal and the dynamics of plant communities. In North America, geomyid, heteromyid and some sciurid rodents have specialized cheek pouches for transporting seeds from plant source to larder, where they are often eliminated from the pool of plant propagules by consumption. These seed-laden rodents are commonly consumed by snakes as they forage, but unlike raptors, coyotes, bobcats, and other endothermic predators which eat rodents and are known or implicated to be secondary seed dispersers, the role of snakes in seed dispersal remains unexplored. Here, using museum-preserved specimens, we show that in nature three desert-dwelling rattlesnake species consumed heteromyids with seeds in their cheek pouches. By examining the entire gut we discovered, furthermore, that secondarily ingested seeds can germinate in rattlesnake colons. In terms of secondary dispersal, rattlesnakes are best described as diplochorous. Because seed rescue and secondary dispersal in snakes has yet to be investigated, and because numerous other snake species consume granivorous and frugivorous birds and mammals, our observations offer direction for further empirical studies of this unusual but potentially important channel for seed dispersal.
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Affiliation(s)
- Randall S Reiserer
- Museum of Vertebrate Zoology, University of California at Berkeley, Berkeley, CA, USA .,Chiricahua Desert Museum, Rodeo, NM, USA
| | - Gordon W Schuett
- Chiricahua Desert Museum, Rodeo, NM, USA.,Department of Biology and Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | - Harry W Greene
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
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19
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Gelmi-Candusso TA, Heymann EW, Heer K. Effects of zoochory on the spatial genetic structure of plant populations. Mol Ecol 2017; 26:5896-5910. [PMID: 28921766 DOI: 10.1111/mec.14351] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 08/30/2017] [Accepted: 09/05/2017] [Indexed: 01/17/2023]
Abstract
Spatial genetic structure (SGS) of plants results from the nonrandom distribution of related individuals. SGS provides information on gene flow and spatial patterns of genetic diversity within populations. Seed dispersal creates the spatial template for plant distribution. Thus, in zoochorous plants, dispersal mode and disperser behaviour might have a strong impact on SGS. However, many studies only report the taxonomic group of seed dispersers, without further details. The recent increase in studies on SGS provides the opportunity to review findings and test for the influence of dispersal mode, taxonomic affiliation of dispersers and their behaviour. We compared the proportions of studies with SGS among groups and tested for differences in strength of SGS using Sp statistics. The presence of SGS differed among taxonomic groups, with reduced presence in plants dispersed by birds. Strength of SGS was instead significantly influenced by the behaviour of seed dispersal vectors, with higher SGS in plant species dispersed by animals with behavioural traits that result in short seed dispersal distances. We observed high variance in the strength of SGS in plants dispersed by animals that actively or passively accumulate seeds. Additionally, we found SGS was also affected by pollination and marker type used. Our study highlights the importance of vector behaviour on SGS even in the presence of variance created by other factors. Thus, more detailed information on the behaviour of seed dispersers would contribute to better understand which factors shape the spatial scale of gene flow in animal-dispersed plant species.
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Affiliation(s)
- Tiziana A Gelmi-Candusso
- Verhaltensökologie & Soziobiologie, Deutsches Primatenzentrum - Leibniz-Institut für Primatenforschung, Göttingen, Germany
| | - Eckhard W Heymann
- Verhaltensökologie & Soziobiologie, Deutsches Primatenzentrum - Leibniz-Institut für Primatenforschung, Göttingen, Germany
| | - Katrin Heer
- Naturschutzbiologie, Phillips-Universität Marburg, Marburg, Germany
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20
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Monthe FK, Hardy OJ, Doucet JL, Loo J, Duminil J. Extensive seed and pollen dispersal and assortative mating in the rain forest tree Entandrophragma cylindricum (Meliaceae) inferred from indirect and direct analyses. Mol Ecol 2017; 26:5279-5291. [PMID: 28734064 DOI: 10.1111/mec.14241] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 04/17/2017] [Accepted: 07/05/2017] [Indexed: 02/02/2023]
Abstract
Pollen and seed dispersal are key processes affecting the demographic and evolutionary dynamics of plant species and are also important considerations for the sustainable management of timber trees. Through direct and indirect genetic analyses, we studied the mating system and the extent of pollen and seed dispersal in an economically important timber species, Entandrophragma cylindricum (Meliaceae). We genotyped adult trees, seeds and saplings from a 400-ha study plot in a natural forest from East Cameroon using eight nuclear microsatellite markers. The species is mainly outcrossed (t = 0.92), but seeds from the same fruit are often pollinated by the same father (correlated paternity, rp = 0.77). An average of 4.76 effective pollen donors (Nep ) per seed tree contributes to the pollination. Seed dispersal was as extensive as pollen dispersal, with a mean dispersal distance in the study plot approaching 600 m, and immigration rates from outside the plot to the central part of the plot reaching 40% for both pollen and seeds. Extensive pollen- and seed-mediated gene flow is further supported by the weak, fine-scale spatial genetic structure (Sp statistic = 0.0058), corresponding to historical gene dispersal distances (σg ) reaching approximately 1,500 m. Using an original approach, we showed that the relatedness between mating individuals (Fij = 0.06) was higher than expected by chance, given the extent of pollen dispersal distances (expected Fij = 0.02 according to simulations). This remarkable pattern of assortative mating could be a phenomenon of potentially consequential evolutionary and management significance that deserves to be studied in other plant populations.
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Affiliation(s)
- Franck Kameni Monthe
- Bioversity International, c/o CIFOR Central Africa Regional Office, Yaoundé, Cameroon.,Faculté des Sciences, Service Evolution Biologique et Ecologie, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Olivier J Hardy
- Faculté des Sciences, Service Evolution Biologique et Ecologie, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Jean-Louis Doucet
- Foresterie Tropicale, Gestion des Ressources Forestières, BIOSE, Gembloux Agro-Bio Tech, Université de Liège, Gembloux, Belgium
| | - Judy Loo
- Bioversity International, Rome, Italy
| | - Jérôme Duminil
- Bioversity International, c/o CIFOR Central Africa Regional Office, Yaoundé, Cameroon.,Faculté des Sciences, Service Evolution Biologique et Ecologie, Université Libre de Bruxelles, Bruxelles, Belgium.,Institut de Recherche pour le Développement, UMR-DIADE, Montpellier, France
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21
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Ismail SA, Ghazoul J, Ravikanth G, Kushalappa CG, Uma Shaanker R, Kettle CJ. Evaluating realized seed dispersal across fragmented tropical landscapes: a two-fold approach using parentage analysis and the neighbourhood model. THE NEW PHYTOLOGIST 2017; 214:1307-1316. [PMID: 28134981 DOI: 10.1111/nph.14427] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 12/08/2016] [Indexed: 06/06/2023]
Abstract
Despite the importance of seed dispersal for survival of plant species in fragmented landscapes, data on seed dispersal at landscape scales remain sparse. Effective seed dispersal among fragments determines recolonization and plant species persistence in such landscapes. We present the first large-scale (216-km2 ) direct estimates of realized seed dispersal of a high-value timber tree (Dysoxylum malabaricum) across an agro-forest landscape in the Western Ghats, India. Based upon an exhaustive inventory of adult trees and a sample of 488 seedlings all genotyped at 10 microsatellite loci, we estimated realized seed dispersal using parentage analysis and the neighbourhood model. Our estimates found that most realized seed dispersal was within 200 m, which is insufficient to effectively bridge the distances between forest patches. We conclude that using mobility of putative animal dispersers can be misleading when estimating tropical tree species vulnerability to habitat fragmentation. This raises serious concerns about the potential of many tropical trees to recolonize isolated forest patches where high-value tree species have already been removed.
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Affiliation(s)
- Sascha A Ismail
- ETH Zürich, Institute of Terrestrial Ecosystems, Ecosystem Management, Zürich, CH-8092, Switzerland
| | - Jaboury Ghazoul
- ETH Zürich, Institute of Terrestrial Ecosystems, Ecosystem Management, Zürich, CH-8092, Switzerland
| | - Gudasalamani Ravikanth
- Ashoka Trust for Research in Ecology and the Environment, Royal Enclave, Srirampura, Jakkur Post, Bangalore, 560064, India
| | - Cheppudira G Kushalappa
- College of Forestry, University of Agricultural and Horticultural Sciences (Shimoga), Ponnampet, Karnataka, 571216, India
| | - Ramanan Uma Shaanker
- Ashoka Trust for Research in Ecology and the Environment, Royal Enclave, Srirampura, Jakkur Post, Bangalore, 560064, India
- Department of Crop Physiology, University of Agricultural Sciences, GKVK Campus, Bangalore, 560065, India
| | - Chris J Kettle
- ETH Zürich, Institute of Terrestrial Ecosystems, Ecosystem Management, Zürich, CH-8092, Switzerland
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22
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Brommer JE, Wistbacka R, Selonen V. Immigration ensures population survival in the Siberian flying squirrel. Ecol Evol 2017; 7:1858-1868. [PMID: 28331593 PMCID: PMC5355189 DOI: 10.1002/ece3.2807] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/10/2016] [Accepted: 01/11/2017] [Indexed: 11/24/2022] Open
Abstract
Linking dispersal to population growth remains a challenging task and is a major knowledge gap, for example, for conservation management. We studied relative roles of different demographic rates behind population growth in Siberian flying squirrels in two nest-box breeding populations in western Finland. Adults and offspring were captured and individually identifiable. We constructed an integrated population model, which estimated all relevant annual demographic rates (birth, local [apparent] survival, and immigration) as well as population growth rates. One population (studied 2002-2014) fluctuated around a steady-state equilibrium, whereas the other (studied 1995-2014) showed a numerical decline. Immigration was the demographic rate which showed clear correlations to annual population growth rates in both populations. Population growth rate was density dependent in both populations. None of the demographic rates nor the population growth rate correlated across the two study populations, despite their proximity suggesting that factors regulating the dynamics are determined locally. We conclude that flying squirrels may persist in a network of uncoupled subpopulations, where movement between subpopulations is of critical importance. Our study supports the view that dispersal has the key role in population survival of a small forest rodent.
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Affiliation(s)
| | | | - Vesa Selonen
- Department of BiologyUniversity of TurkuTurkuFinland
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23
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Jiménez A, Weigelt B, Santos-Guerra A, Caujapé-Castells J, Fernández-Palacios JM, Conti E. Surviving in isolation: genetic variation, bottlenecks and reproductive strategies in the Canarian endemic Limonium macrophyllum (Plumbaginaceae). Genetica 2017; 145:91-104. [PMID: 28108874 DOI: 10.1007/s10709-017-9948-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 01/03/2017] [Indexed: 11/28/2022]
Abstract
Oceanic archipelagos are typically rich in endemic taxa, because they offer ideal conditions for diversification and speciation in isolation. One of the most remarkable evolutionary radiations on the Canary Islands comprises the 16 species included in Limonium subsection Nobiles, all of which are subject to diverse threats, and legally protected. Since many of them are single-island endemics limited to one or a few populations, there exists a risk that a loss of genetic variation might limit their long-term survival. In this study, we used eight newly developed microsatellite markers to characterize the levels of genetic variation and inbreeding in L. macrophyllum, a species endemic to the North-east of Tenerife that belongs to Limonium subsection Nobiles. We detected generally low levels of genetic variation over all populations (H T = 0.363), and substantial differentiation among populations (F ST = 0.188; R ST = 0.186) coupled with a negligible degree of inbreeding (F = 0.042). Obligate outcrossing may have maintained L. macrophyllum relatively unaffected by inbreeding despite the species' limited dispersal ability and the genetic bottlenecks likely caused by a prolonged history of grazing. Although several factors still constitute a risk for the conservation of L. macrophyllum, the lack of inbreeding and the recent positive demographic trends observed in the populations of this species are factors that favour its future persistence.
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Affiliation(s)
- Ares Jiménez
- Department of Systematic and Evolutionary Botany and Botanical Garden, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland.
| | - Barbara Weigelt
- Department of Systematic and Evolutionary Botany and Botanical Garden, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland
| | - Arnoldo Santos-Guerra
- Instituto Canario de Investigaciones Agrarias, Calle Guaidil 16, 38280, Tegueste, Tenerife, Spain
| | - Juli Caujapé-Castells
- Jardín Botánico Canario "Viera y Clavijo" - Unidad Asociada CSIC, Cabildo de Gran Canaria, Camino al palmeral 15, 35017, Las Palmas de Gran Canaria, Spain
| | - José María Fernández-Palacios
- Island Ecology and Biogeography Research Group, Universidad de La Laguna, Avda. Astrofísico Francisco Sánchez s/n, 38109, La Laguna, Tenerife, Spain
| | - Elena Conti
- Department of Systematic and Evolutionary Botany and Botanical Garden, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland
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24
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Santos AS, Cazetta E, Dodonov P, Faria D, Gaiotto FA. Landscape-scale deforestation decreases gene flow distance of a keystone tropical palm, Euterpe edulis Mart (Arecaceae). Ecol Evol 2016; 6:6586-6598. [PMID: 27777732 PMCID: PMC5058530 DOI: 10.1002/ece3.2341] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 06/14/2016] [Accepted: 07/04/2016] [Indexed: 11/25/2022] Open
Abstract
Habitat loss represents one of the main threats to tropical forests, which have reached extremely high rates of species extinction. Forest loss negatively impacts biodiversity, affecting ecological (e.g., seed dispersal) and genetic (e.g., genetic diversity and structure) processes. Therefore, understanding how deforestation influences genetic resources is strategic for conservation. Our aim was to empirically evaluate the effects of landscape‐scale forest reduction on the spatial genetic structure and gene flow of Euterpe edulis Mart (Arecaceae), a palm tree considered a keystone resource for many vertebrate species. This study was carried out in nine forest remnants in the Atlantic Forest, northeastern Brazil, located in landscapes within a gradient of forest cover (19–83%). We collected leaves of 246 adults and 271 seedlings and performed genotyping using microsatellite markers. Our results showed that the palm populations had low spatial genetic structure, indicating that forest reduction did not influence this genetic parameter for neither seedlings nor adults. However, forest loss decreased the gene flow distance, which may negatively affect the genetic diversity of future generations by increasing the risk of local extinction of this keystone palm. For efficient strategies of genetic variability conservation and maintenance of gene flow in E. edulis, we recommend the maintenance of landscapes with intermediary to high levels of forest cover, that is, forest cover above 40%.
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Affiliation(s)
- Alesandro S Santos
- Pós-Graduação em Ecologia e Conservação da Biodiversidade Universidade Estadual de Santa Cruz Rodovia Ilhéus-Itabuna, km 16 Ilhéus CEP 45662-900 Brazil
| | - Eliana Cazetta
- Laboratório de Ecologia Aplicada à Conservação Departamento de Ciências Biológicas Universidade Estadual de Santa Cruz Rodovia Ilhéus-Itabuna, km 16 Ilhéus CEP 45662-900 Brazil
| | - Pavel Dodonov
- Laboratório de Ecologia Aplicada à Conservação Departamento de Ciências Biológicas Universidade Estadual de Santa Cruz Rodovia Ilhéus-Itabuna, km 16 Ilhéus CEP 45662-900 Brazil
| | - Deborah Faria
- Laboratório de Ecologia Aplicada à Conservação Departamento de Ciências Biológicas Universidade Estadual de Santa Cruz Rodovia Ilhéus-Itabuna, km 16 Ilhéus CEP 45662-900 Brazil
| | - Fernanda A Gaiotto
- Laboratório de Marcadores Moleculares Centro de Biotecnologia e Genética Universidade Estadual de Santa Cruz Rodovia Ilhéus-Itabuna, km 16 Ilhéus CEP 45662-900 Brazil
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Rico Y, Wagner HH. Reduced fine-scale spatial genetic structure in grazed populations of Dianthus carthusianorum. Heredity (Edinb) 2016; 117:367-374. [PMID: 27381322 DOI: 10.1038/hdy.2016.45] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Revised: 05/02/2016] [Accepted: 05/25/2016] [Indexed: 12/25/2022] Open
Abstract
Strong spatial genetic structure in plant populations can increase homozygosity, reducing genetic diversity and adaptive potential. The strength of spatial genetic structure largely depends on rates of seed dispersal and pollen flow. Seeds without dispersal adaptations are likely to be dispersed over short distances within the vicinity of the mother plant, resulting in spatial clustering of related genotypes (fine-scale spatial genetic structure, hereafter spatial genetic structure (SGS)). However, primary seed dispersal by zoochory can promote effective dispersal, increasing the mixing of seeds and influencing SGS within plant populations. In this study, we investigated the effects of seed dispersal by rotational sheep grazing on the strength of SGS and genetic diversity using 11 nuclear microsatellites for 49 populations of the calcareous grassland forb Dianthus carthusianorum. Populations connected by rotational sheep grazing showed significantly weaker SGS and higher genetic diversity than populations in ungrazed grasslands. Independent of grazing treatment, small populations showed significantly stronger SGS and lower genetic diversity than larger populations, likely due to genetic drift. A lack of significant differences in the strength of SGS and genetic diversity between populations that were recently colonized and pre-existing populations suggested that populations colonized after the reintroduction of rotational sheep grazing were likely founded by colonists from diverse source populations. We conclude that dispersal by rotational sheep grazing has the potential to considerably reduce SGS within D. carthusianorum populations. Our study highlights the effectiveness of landscape management by rotational sheep grazing to importantly reduce genetic structure at local scales within restored plant populations.
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Affiliation(s)
- Y Rico
- Department of Ecology and Evolutionary Biology, University of Toronto, Mississauga, Ontario, Canada.,Centro Regional del Bajío, CONACYT, Instituto Nacional de Ecología, A.C., Avenida Lázaro Cárdenas, Pátzcuaro, Michoacán, México
| | - H H Wagner
- Centro Regional del Bajío, CONACYT, Instituto Nacional de Ecología, A.C., Avenida Lázaro Cárdenas, Pátzcuaro, Michoacán, México
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Giombini MI, Bravo SP, Tosto DS. The key role of the largest extant Neotropical frugivore (Tapirus terrestris) in promoting admixture of plant genotypes across the landscape. Biotropica 2016. [DOI: 10.1111/btp.12328] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mariano I. Giombini
- IEGEBA - Instituto de Ecología Genética y Evolución de Buenos Aires; UBA-CONICET; Facultad de Ciencias Exactas y Naturales; Universidad de Buenos Aires; 4° piso, Pabellón II, Ciudad Universitaria (C1428EHA) Ciudad Autónoma de Buenos Aires Argentina
- Instituto de Biotecnología; Instituto Nacional de Tecnología Agropecuaria INTA-Castelar; Dr. Nicolás Repetto y De los Reseros s/N (B1686IGC) Hurlingham Buenos Aires Argentina
| | - Susana P. Bravo
- IEGEBA - Instituto de Ecología Genética y Evolución de Buenos Aires; UBA-CONICET; Facultad de Ciencias Exactas y Naturales; Universidad de Buenos Aires; 4° piso, Pabellón II, Ciudad Universitaria (C1428EHA) Ciudad Autónoma de Buenos Aires Argentina
| | - Daniela S. Tosto
- Instituto de Biotecnología; Instituto Nacional de Tecnología Agropecuaria INTA-Castelar; Dr. Nicolás Repetto y De los Reseros s/N (B1686IGC) Hurlingham Buenos Aires Argentina
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27
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Helsen K, Meekers T, Vranckx G, Roldán-Ruiz I, Vandepitte K, Honnay O. A direct assessment of realized seed and pollen flow within and between two isolated populations of the food-deceptive orchid Orchis mascula. PLANT BIOLOGY (STUTTGART, GERMANY) 2016; 18:139-46. [PMID: 25941020 DOI: 10.1111/plb.12342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 04/28/2015] [Indexed: 05/09/2023]
Abstract
Gene flow can counteract the loss of genetic diversity caused by genetic drift in small populations. For this reason, clearly understanding gene flow patterns is of the highest importance across fragmented landscapes. However, gene flow patterns are not only dependent upon the degree of spatial isolation of fragmented populations, but are also dependent upon the life-history traits of the species. Indeed, habitat fragmentation effects appear especially unpredictable for food-deceptive orchid species, because of their highly specialised seed and pollen dispersal mechanisms. In this study we used amplified fragment length polymorphism markers and subsequent parentage and spatial autocorrelation analysis to quantify the extent and the patterns of realized gene flow within and between two adjacent fragmented populations of the food-deceptive Orchis mascula. We observed considerable gene flow between both populations, occurring mainly through pollen dispersal. Seed dispersal, on the other hand, was mainly limited to the first few meters from the mother plant in both populations, although at least one among-population seed dispersal event was observed. This, in turn, resulted in a significant spatial genetic structure for both populations. Although genetic diversity was high in both populations and mainly outcrossing occurred, reproductive output was strongly skewed toward a limited number of successful adult plants. These observed patterns are likely due to the different pollinator behaviour associated with food-deceptive plants. We conclude that these populations can be considered viable under their current fragmented state.
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Affiliation(s)
- K Helsen
- Plant Conservation and Population Biology, Biology Department, University of Leuven, Heverlee, Belgium
| | - T Meekers
- Plant Conservation and Population Biology, Biology Department, University of Leuven, Heverlee, Belgium
| | - G Vranckx
- Plant Conservation and Population Biology, Biology Department, University of Leuven, Heverlee, Belgium
| | - I Roldán-Ruiz
- Growth and Development, Unit Plant, Institute for Agricultural and Fisheries Research, Melle, Belgium
| | - K Vandepitte
- Plant Conservation and Population Biology, Biology Department, University of Leuven, Heverlee, Belgium
| | - O Honnay
- Plant Conservation and Population Biology, Biology Department, University of Leuven, Heverlee, Belgium
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28
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Using genetic data to estimate diffusion rates in heterogeneous landscapes. J Math Biol 2015; 73:397-422. [DOI: 10.1007/s00285-015-0954-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 11/19/2015] [Indexed: 10/22/2022]
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Individual spatial aggregation correlates with between-population variation in fine-scale genetic structure of Silene ciliata (Caryophyllaceae). Heredity (Edinb) 2015; 116:417-23. [PMID: 26604191 DOI: 10.1038/hdy.2015.102] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 09/29/2015] [Accepted: 10/13/2015] [Indexed: 11/08/2022] Open
Abstract
Fine-scale genetic structure (FSGS) can vary among populations within species depending on multiple demographic and environmental factors. Theoretical models predict that FSGS should decrease in high-density populations and increase in populations where individuals are spatially aggregated. However, few empirical studies have compared FSGS between populations with different degrees of individual spatial aggregation and microhabitat heterogeneity. In this work, we studied the relationship between spatial and genetic structure in five populations of alpine specialist Silene ciliata Poiret (Caryophyllaceae). We mapped all individuals in each population and genotyped 96 of them using 10 microsatellite markers. We found significant FSGS consistent with an isolation-by-distance process in three of the five populations. The intensity of FSGS was positively associated with individual spatial aggregation. However, no association was found between FSGS and global population density or microhabitat heterogeneity. Overall, our results support theoretical studies indicating that stronger spatial aggregation tends to increase the magnitude of FSGS. They also highlight the relevance of characterizing local plant distribution and microhabitat to better understand the mechanisms that generate intraspecific variation in FSGS across landscapes.
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Pascov CM, Nevill PG, Elliott CP, Majer JD, Anthony JM, Krauss SL. The critical role of ants in the extensive dispersal of Acacia seeds revealed by genetic parentage assignment. Oecologia 2015; 179:1123-34. [PMID: 26255273 DOI: 10.1007/s00442-015-3400-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 07/13/2015] [Indexed: 11/29/2022]
Abstract
Ants are prominent seed dispersal agents in many ecosystems, and dispersal distances are small in comparison with vertebrate dispersal agents. However, the distance and distribution of ant-mediated dispersal in arid/semi-arid environments remains poorly explored. We used microsatellite markers and parentage assignment to quantify the distance and distribution of dispersed seeds of Acacia karina, retrieved from the middens of Iridomyrmex agilis and Melophorus turneri perthensis. From parentage assignment, we could not distinguish the maternal from each parent pair assigned to each seed, so we applied two approaches to estimate dispersal distances, one conservative (CONS), where the parent closest to the ant midden was considered to be maternal, and the second where both parents were deemed equally likely (EL) to be maternal, and used both distances. Parentage was assigned to 124 seeds from eight middens. Maximum seed dispersal distances detected were 417 m (CONS) and 423 m (EL), more than double the estimated global maximum. Mean seed dispersal distances of 40 m (±5.8 SE) (CONS) and 79 m (±6.4 SE) (EL) exceeded the published global average of 2.24 m (±7.19 SD) by at least one order of magnitude. For both approaches and both ant species, seed dispersal was predominantly (44-84% of all seeds) within 50 m from the maternal source, with fewer dispersal events at longer distances. Ants in this semi-arid environment have demonstrated a greater capacity to disperse seeds than estimated elsewhere, which highlights their important role in this system, and suggests significant novel ecological and evolutionary consequences for myrmecochorous species in arid/semi-arid Australia.
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Affiliation(s)
- Caitlin M Pascov
- Botanic Gardens and Parks Authority, Kings Park and Botanic Garden, West Perth, WA, 6005, Australia.,School of Plant Biology, The University of Western Australia, Nedlands, WA, 6009, Australia
| | - Paul G Nevill
- Botanic Gardens and Parks Authority, Kings Park and Botanic Garden, West Perth, WA, 6005, Australia. .,School of Plant Biology, The University of Western Australia, Nedlands, WA, 6009, Australia. .,Department of Environment and Agriculture, Curtin University, Bentley, WA, 6102, Australia.
| | - Carole P Elliott
- Botanic Gardens and Parks Authority, Kings Park and Botanic Garden, West Perth, WA, 6005, Australia.,School of Veterinary and Life Sciences, Environment and Conservation Sciences, Murdoch University, Perth, WA, 6150, Australia
| | - Jonathan D Majer
- School of Plant Biology, The University of Western Australia, Nedlands, WA, 6009, Australia.,Department of Environment and Agriculture, Curtin University, Bentley, WA, 6102, Australia
| | - Janet M Anthony
- Botanic Gardens and Parks Authority, Kings Park and Botanic Garden, West Perth, WA, 6005, Australia.,School of Plant Biology, The University of Western Australia, Nedlands, WA, 6009, Australia
| | - Siegfried L Krauss
- Botanic Gardens and Parks Authority, Kings Park and Botanic Garden, West Perth, WA, 6005, Australia.,School of Plant Biology, The University of Western Australia, Nedlands, WA, 6009, Australia
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Helsen K, Jacquemyn H, Honnay O. Hidden founder effects: small-scale spatial genetic structure in recently established populations of the grassland specialist plant Anthyllis vulneraria. Mol Ecol 2015; 24:2715-28. [PMID: 25892081 DOI: 10.1111/mec.13207] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 04/09/2015] [Accepted: 04/14/2015] [Indexed: 01/15/2023]
Abstract
The long-term establishment success of founder plant populations has been commonly assessed based on the measures of population genetic diversity and among population genetic differentiation, with founder populations expected to carry sufficient genetic diversity when population establishment is the result of many colonists from multiple source populations (the 'migrant pool' colonization model). Theory, however, predicts that, after initial colonization, rapid population expansion may result in a fast increase in the extent of spatial genetic structure (SGS), independent of extant genetic diversity. This SGS can reduce long-term population viability by increasing inbreeding. Using 12 microsatellite markers, we inferred colonization patterns in four recent populations of the grassland specialist plant Anthyllis vulneraria and compared the extent of SGS between recently established and old populations. Assignment analyses of the individuals of recent population based on the genetic composition of nine adjacent putative source populations suggested the occurrence of the 'migrant pool' colonization model, further confirmed by high genetic diversity within and low genetic differentiation among recent populations. Population establishment, however, resulted in the build-up of strong SGS, most likely as a result of spatially restricted recruitment of the progeny of initial colonists. Although reduced, significant SGS was nonetheless observed to persist in old populations. The presence of SGS was in all populations associated with elevated inbreeding coefficients, potentially affecting the long-term viability of these populations. In conclusion, this study illustrates the importance of studying SGS next to population genetic diversity and differentiation to adequately infer colonization patterns and long-term establishment success of plant species.
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Affiliation(s)
- Kenny Helsen
- Plant Conservation and Population Biology, Biology Department, University of Leuven, Kasteelpark Arenberg 31, Heverlee, B-3001, Belgium
| | - Hans Jacquemyn
- Plant Conservation and Population Biology, Biology Department, University of Leuven, Kasteelpark Arenberg 31, Heverlee, B-3001, Belgium
| | - Olivier Honnay
- Plant Conservation and Population Biology, Biology Department, University of Leuven, Kasteelpark Arenberg 31, Heverlee, B-3001, Belgium
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32
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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.
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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)
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Driscoll DA, Banks SC, Barton PS, Ikin K, Lentini P, Lindenmayer DB, Smith AL, Berry LE, Burns EL, Edworthy A, Evans MJ, Gibson R, Heinsohn R, Howland B, Kay G, Munro N, Scheele BC, Stirnemann I, Stojanovic D, Sweaney N, Villaseñor NR, Westgate MJ. The trajectory of dispersal research in conservation biology. Systematic review. PLoS One 2014; 9:e95053. [PMID: 24743447 PMCID: PMC3990620 DOI: 10.1371/journal.pone.0095053] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 03/23/2014] [Indexed: 11/18/2022] Open
Abstract
Dispersal knowledge is essential for conservation management, and demand is growing. But are we accumulating dispersal knowledge at a pace that can meet the demand? To answer this question we tested for changes in dispersal data collection and use over time. Our systematic review of 655 conservation-related publications compared five topics: climate change, habitat restoration, population viability analysis, land planning (systematic conservation planning) and invasive species. We analysed temporal changes in the: (i) questions asked by dispersal-related research; (ii) methods used to study dispersal; (iii) the quality of dispersal data; (iv) extent that dispersal knowledge is lacking, and; (v) likely consequences of limited dispersal knowledge. Research questions have changed little over time; the same problems examined in the 1990s are still being addressed. The most common methods used to study dispersal were occupancy data, expert opinion and modelling, which often provided indirect, low quality information about dispersal. Although use of genetics for estimating dispersal has increased, new ecological and genetic methods for measuring dispersal are not yet widely adopted. Almost half of the papers identified knowledge gaps related to dispersal. Limited dispersal knowledge often made it impossible to discover ecological processes or compromised conservation outcomes. The quality of dispersal data used in climate change research has increased since the 1990s. In comparison, restoration ecology inadequately addresses large-scale process, whilst the gap between knowledge accumulation and growth in applications may be increasing in land planning. To overcome apparent stagnation in collection and use of dispersal knowledge, researchers need to: (i) improve the quality of available data using new approaches; (ii) understand the complementarities of different methods and; (iii) define the value of different kinds of dispersal information for supporting management decisions. Ambitious, multi-disciplinary research programs studying many species are critical for advancing dispersal research.
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Affiliation(s)
- Don A. Driscoll
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
- * E-mail:
| | - Sam C. Banks
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Philip S. Barton
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Karen Ikin
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Pia Lentini
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
- School of Botany, University of Melbourne, Melbourne, Victoria, Australia
| | - David B. Lindenmayer
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Annabel L. Smith
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Laurence E. Berry
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Emma L. Burns
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Amanda Edworthy
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Maldwyn J. Evans
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Rebecca Gibson
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - Rob Heinsohn
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Brett Howland
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Geoff Kay
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Nicola Munro
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Ben C. Scheele
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Ingrid Stirnemann
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Dejan Stojanovic
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Nici Sweaney
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Nélida R. Villaseñor
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Martin J. Westgate
- ARC Centre of Excellence for Environmental Decisions, the NERP Environmental Decisions Hub, Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia
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Trapnell DW, Hamrick JL, Ishibashi CD, Kartzinel TR. Genetic inference of epiphytic orchid colonization; it may only take one. Mol Ecol 2013; 22:3680-92. [DOI: 10.1111/mec.12338] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 03/20/2013] [Accepted: 03/26/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Dorset W. Trapnell
- Department of Plant Biology; University of Georgia; Athens Georgia 30602 USA
| | - J. L. Hamrick
- Department of Plant Biology; University of Georgia; Athens Georgia 30602 USA
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Forest fragmentation and edge effects on the genetic structure ofClusia sphaerocarpaandC. lechleri(Clusiaceae) in tropical montane forests. JOURNAL OF TROPICAL ECOLOGY 2013. [DOI: 10.1017/s0266467413000345] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Abstract:Fragmentation of tropical forests influences abiotic and biotic processes that affect the genetic structure of plant populations. In forest fragments, edge effects, i.e. changes of abiotic and biotic factors at forest edges, may be prevalent. In two forest fragments (c. 200 ha atc. 2450 m asl) of tropical montane forest in Bolivia, sympatric populations of the dioecious tree speciesClusia sphaerocarpaandC. lechleriwere used as case study species to compare genetic diversity and small-scale genetic structure (SGS) between edge and interior habitats. Eight microsatellite markers were employed to genotype 343 individuals including adults, juveniles and seedlings ofC. sphaerocarpaand 196 ofC. lechleri. Genetic differentiation was found between habitats in both species (ΦRT= 0.071 forC. sphaerocarpaand ΦRT= 0.028 forC. lechleri) and among ages inC. sphaerocarpa(ΦRT= 0.016). Overall, SGS was weak but significant with more pronounced SGS inC. lechleri(Sp= 0.0128) than inC. sphaerocarpa(Sp= 0.0073). However, positive spatial genetic autocorrelation extended only up to 10 m. ForC. sphaerocarpa, SGS was stronger in seedling and juvenile stages than in adults and in the forest interior than at forest edges. Our results show that edge effects can extend to the genetic level by breaking-up local genetic structures, probably due to increased gene flow and enhanced pollination and seed-dispersal interactions at forest edges.
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Barbosa CEA, Misiewicz TM, Fine PVA, Costa FRC. Plant ontogeny, spatial distance, and soil type influence patterns of relatedness in a common Amazonian tree. PLoS One 2013; 8:e62639. [PMID: 23667502 PMCID: PMC3646837 DOI: 10.1371/journal.pone.0062639] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 03/22/2013] [Indexed: 11/18/2022] Open
Abstract
The formation of spatial genetic structure (SGS) may originate from different patterns of seed deposition in the landscape, and is mostly determined by seed dispersal limitation. After dispersal, mechanisms such as filtering by environmental factors or attack by herbivores/pathogens throughout plant development stages, and potentially either disrupt or intensify SGS patterns. We investigated how the genotype of Protium subserratum (Burseraceae), a common tree species in the Ducke Reserve, Brazil, is distributed across the landscape. We used seven microsatellite markers to assess the SGS among plants at different life stages and in different environments. By quantifying the patterns of relatedness among plants of different sizes, we inferred the ontogenetic stage in which SGS changes occurred, and compared these effects across soil types. Relatedness among seedlings decreased when distance between seedlings increased, especially for the youngest seedlings. However, this trend was not continued by older plants, as relatedness values were higher among neighboring individuals of the juvenile and adult size class. Contrasting relatedness patterns between seedlings and larger individuals suggests a trade-off between the negative effects of being near closely-related adults (e.g. due to herbivore and pathogen attack) and the advantage of being in a site favorable to establishment. We also found that soil texture strongly influenced density-dependence patterns, as young seedlings in clay soils were more related to each other than were seedlings in bottomland sandy soils, suggesting that the mechanisms that create and maintain patterns of SGS within a population may interact with environmental heterogeneity.
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Affiliation(s)
- Carlos Eduardo A Barbosa
- Graduate Program in Ecology, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas, Brazil.
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Plants on the move: The role of seed dispersal and initial population establishment for climate-driven range expansions. ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY 2011. [DOI: 10.1016/j.actao.2011.05.001] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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38
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Forget PM, Jordano P, Lambert JE, Böhning-Gaese K, Traveset A, Wright SJ. Frugivores and seed dispersal (1985–2010); the ‘seeds’ dispersed, established and matured. ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY 2011. [DOI: 10.1016/j.actao.2011.09.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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