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Bogdziewicz M, Kelly D, Tanentzap AJ, Thomas P, Foest J, Lageard J, Hacket-Pain A. Reproductive collapse in European beech results from declining pollination efficiency in large trees. GLOBAL CHANGE BIOLOGY 2023. [PMID: 37177909 DOI: 10.1111/gcb.16730] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 04/13/2023] [Indexed: 05/15/2023]
Abstract
Climate warming increases tree mortality which will require sufficient reproduction to ensure population viability. However, the response of tree reproduction to climate change remains poorly understood. Warming can reduce synchrony and interannual variability of seed production ("masting breakdown") which can increase seed predation and decrease pollination efficiency in trees. Here, using 40 years of observations of individual seed production in European beech (Fagus sylvatica), we showed that masting breakdown results in declining viable seed production over time, in contrast to the positive trend apparent in raw seed count data. Furthermore, tree size modulates the consequences of masting breakdown on viable seed production. While seed predation increased over time mainly in small trees, pollination efficiency disproportionately decreased in larger individuals. Consequently, fecundity declined over time across all size classes, but the overall effect was greatest in large trees. Our study showed that a fundamental biological relationship-correlation between tree size and viable seed production-has been reversed as the climate has warmed. That reversal has diverse consequences for forest dynamics; including for stand- and biogeographical-level dynamics of forest regeneration. The tree size effects suggest management options to increase forest resilience under changing climates.
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Affiliation(s)
- Michał Bogdziewicz
- Forest Biology Center, Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - Dave Kelly
- Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Andrew J Tanentzap
- Ecosystems and Global Change Group, Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Peter Thomas
- School of Life Sciences, Keele University, Keele, UK
| | - Jessie Foest
- Department of Geography and Planning, School of Environmental Sciences, University of Liverpool, Liverpool, UK
| | - Jonathan Lageard
- Department of Natural Sciences, Manchester Metropolitan University, Manchester, UK
| | - Andrew Hacket-Pain
- Department of Geography and Planning, School of Environmental Sciences, University of Liverpool, Liverpool, UK
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Chávez-Cortázar A, Oyama K, Ochoa-Zavala M, Mata-Rosas M, Veltjen E, Samain MS, Quesada M. Conservation genetics of relict tropical species of Magnolia (section Macrophylla). CONSERV GENET 2021. [DOI: 10.1007/s10592-021-01334-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
AbstractSpecial conservation efforts should be made for relict species, as they usually have small population sizes and restricted distributions, placing them in critical extinction risk. To achieve conservation, information about genetic diversity distribution is needed. Here, using nine nuclear microsatellites, we analyzed 23 populations of five recently described species of Magnolia distributed in Mexico, which were previously assigned to Magnolia dealbata. We aimed to determine the level of genetic diversity and the distribution of genetic variation and proposed conservation measures. Compared to other endemic and relict species, we found a moderate level of genetic diversity in most populations; however, we identified two populations with no genetic variation. Additionally, we found evidence of positive values of inbreeding likely due to geitonogamy. We found a strong population structure, low effective population size, and no evidence of bottlenecks. Patterns of genetic differentiation did not support the morphological distinction of five species, so we hypothesized that the gene pools may instead represent well-differentiated populations of a single species. We argue that the pattern of genetic differentiation is explained by the natural fragmentation of the cloud forests after glaciation events, and the effects of genetic drift in small populations poorly connected by gene flow. Despite the moderate levels of genetic diversity, special attention is needed to guarantee conservation, with emphasis on the populations in the central region of the country as well as the valuable populations identified in the southwestern region.
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Chybicki IJ, Oleksa A, Dering M. Identification of determinants of pollen donor fecundity using the hierarchical neighborhood model. Mol Ecol Resour 2020; 21:781-800. [PMID: 33290637 DOI: 10.1111/1755-0998.13307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 11/24/2020] [Accepted: 12/01/2020] [Indexed: 11/30/2022]
Abstract
Individual differences in male reproductive success drive genetic drift and natural selection, altering genetic variation and phenotypic trait distributions in future generations. Therefore, identifying the determinants of reproductive success is important for understanding the ecology and evolution of plants. Here, based on the spatially explicit mating model (the neighborhood model), we develop a hierarchical probability model that links co-dominant genotypes of offspring and candidate parents with phenotypic determinants of male reproductive success. The model accounts for pollen dispersal, genotyping errors as well as individual variation in selfing, pollen immigration, and differentiation of immigrant pollen pools. Unlike the classic neighborhood model approach, our approach is specially designed to account for excessive variation (overdispersion) in male fecundity. We implemented a Bayesian estimation method (the Windows computer program available at: https://www.ukw.edu.pl/pracownicy/plik/igor_chybicki/1806/) that, among others, allows for selecting phenotypic variables important for male fecundity and assessing the fraction of variance in fecundity (R2 ) explained by selected variables. Simulations showed that our method outperforms both the classic neighborhood model and the two-step approach, where fecundities and the effects of phenotypic variables are estimated separately. The analysis of two data examples showed that in wind-pollinated trees, male fecundity depends on both the amount of produced pollen and the ability to pollen spread. However, despite that the tree size was positively correlated with male fecundity, it explained only a fraction of the total variance in fecundity, indicating the presence of additional factors. Finally, case studies highlighted the importance of accounting for pollen dispersal in the estimation of fecundity determinants.
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Affiliation(s)
- Igor J Chybicki
- Department of Genetics, Kazimierz Wielki University, Bydgoszcz, Poland
| | - Andrzej Oleksa
- Department of Genetics, Kazimierz Wielki University, Bydgoszcz, Poland
| | - Monika Dering
- Institute of Dendrology, Polish Academy of Sciences, Kórnik, Poland.,Department of Silviculture, Poznań University of Life Sciences, Poznań, Poland
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Fan XR, Wagutu GK, Wen XY, Chen SL, Liu YL, Chen YY. Decreasing genetic connectivity in the endangered tree Magnolia patungensis in fragmented forests. Glob Ecol Conserv 2020. [DOI: 10.1016/j.gecco.2020.e01227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Rico Y, Gutiérrez Becerril BA. Species delimitation and genetic structure of two endemic Magnolia species (section Magnolia; Magnoliaceae) in Mexico. Genetica 2019; 147:57-68. [PMID: 30671745 DOI: 10.1007/s10709-019-00052-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 01/17/2019] [Indexed: 11/28/2022]
Abstract
Magnolias are characteristic tree species of the Tropical Montane Cloud Forest (TMCF) in Mexico, an ecosystem that is highly threatened by habitat fragmentation and climate change. In this study, based on DNA sequences from five regions (chloroplast: trnT-trnL, trnK5-matK, trnS-trnG, rpl32-trnL, nuclear: ITS) and seven nuclear microsatellite markers, we aimed to delineate species boundaries between two-endemic species of the TMCF, Magnolia pedrazae and Magnolia schiedeana, and to estimate levels of genetic structure and diversity among populations. Phylogenetic and haplotype network analyses for the chloroplast and ITS regions did not support genetic differentiation as two distinctive species. Results from Bayesian and multivariate cluster analyses based on microsatellite loci showed high genetic differentiation across most populations, which was consistent with a strong and significant pattern of isolation by geographical distance. We found moderate to high levels of population genetic diversity, but it was lower in small populations relative to large populations. Our results suggest a contemporary decrease of genetic connectivity among populations, likely as a consequence of the current decline of suitable TMCF habitat. Managing landscape connectivity among remnant Magnolia populations within protected natural parks and surroundings, and with emphasis of small populations, would be key for the species conservation.
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Affiliation(s)
- Yessica Rico
- CONACYT, Red de Diversidad Biológica del Occidente Mexicano, Instituto de Ecología, A.C., Avenida Lázaro Cárdenas 253, 61600, Pátzcuaro, Michoacán, Mexico.
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Moraes MA, Kubota TYK, Rossini BC, Marino CL, Freitas MLM, Moraes MLT, da Silva AM, Cambuim J, Sebbenn AM. Long-distance pollen and seed dispersal and inbreeding depression in Hymenaea stigonocarpa (Fabaceae: Caesalpinioideae) in the Brazilian savannah. Ecol Evol 2018; 8:7800-7816. [PMID: 30250664 PMCID: PMC6144967 DOI: 10.1002/ece3.4253] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 03/02/2018] [Accepted: 05/14/2018] [Indexed: 02/03/2023] Open
Abstract
Hymenaea stigonocarpa is a neotropical tree that is economically important due to its high-quality wood; however, because it has been exploited extensively, it is currently considered threatened. Microsatellite loci were used to investigate the pollen and seed dispersal, mating patterns, spatial genetic structure (SGS), genetic diversity, and inbreeding depression in H. stigonocarpa adults, juveniles, and open-pollinated seeds, which were sampled from isolated trees in a pasture and trees within a forest fragment in the Brazilian savannah. We found that the species presented a mixed mating system, with population and individual variations in the outcrossing rate (0.53-1.0). The studied populations were not genetically isolated due to pollen and seed flow between the studied populations and between the populations and individuals located outside of the study area. Pollen and seed dispersal occurred over long distances (>8 km); however, the dispersal patterns were isolated by distance, with a high frequency of mating occurring between near-neighbor trees and seeds dispersed near the parent trees. The correlated mating for individual seed trees was higher within than among fruits, indicating that fruits present a high proportion of full-sibs. Genetic diversity and SGS were similar among the populations, but offspring showed evidence of inbreeding, mainly originating from mating among related trees, which suggests inbreeding depression between the seed and adult stages. Selfing resulted in a higher inbreeding depression than mating among relatives, as assessed through survival and height. As the populations are not genetically isolated, both are important targets for in situ conservation to maintain their genetic diversity; for ex situ conservation, seeds can be collected from at least 78 trees in both populations separated by at least 250 m.
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Affiliation(s)
| | | | | | | | | | | | | | - Jose Cambuim
- Faculdade de Engenharia de Ilha Solteira/UNESPIlha SolteiraSPBrazil
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Watanabe S, Takakura KI, Kaneko Y, Noma N, Nishida T. Skewed male reproductive success and pollen transfer in a small fragmented population of the heterodichogamous tree Machilus thunbergii. JOURNAL OF PLANT RESEARCH 2018; 131:623-631. [PMID: 29468326 DOI: 10.1007/s10265-018-1018-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 02/01/2018] [Indexed: 06/08/2023]
Abstract
Heterodichogamy is defined as the presence of two flower morphs that exhibit the male and female functions at different times among individuals within a population. Heterodichogamy is regarded as an adaptation to promote outcrossing through enhanced inter-morph mating, together with a 1:1 morph ratio. However, in highly fragmented populations, the morph ratio may be more likely to be biased by stochastic events. In such a situation, individuals of a minority morph within a population are expected to have higher reproductive success than those of a majority morph, which may suffer from pollen shortages of the minority morph. In this paper, we evaluated mating patterns and male reproductive success in a highly fragmented population of Machilus thunbergii, a putative heterodichogamous evergreen laurel tree. Results of paternity analysis indicated that the selfing rate was not clearly different between the two morphs. In contrast, the proportion of intra-morph mating was higher in the majority-morph (MM) mother trees than in the minority-morph (MF) mother trees. Bayesian estimated male reproductive success indicated that male reproductive success was higher in minority-morph (MF) than in majority-morph (MM) mother trees. These findings indicate that (1) the majority morph mothers, suffering a shortage of the opposite morph pollen, could partly compensate for the reduced reproductive success by intra-morph mating rather than by selfing, and (2) negative-frequency dependent selection may be involved in the maintenance of the two morphs.
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Affiliation(s)
- Shuntaro Watanabe
- Field Science Education and Research Centre (FSERC), Kyoto University, Kitashirakawaoiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.
| | - Koh-Ichi Takakura
- School of Environmental Science, The University of Shiga Prefecture, 2500 Hassaka-cho, Hikone, Shiga, 522-8533, Japan
| | - Yuko Kaneko
- Natural Science Laboratory, Toyo University, 5-28-20, Hakusan, Bunkyo-ku, Tokyo, 112-8606, Japan
| | - Naohiko Noma
- School of Environmental Science, The University of Shiga Prefecture, 2500 Hassaka-cho, Hikone, Shiga, 522-8533, Japan
| | - Takayoshi Nishida
- School of Environmental Science, The University of Shiga Prefecture, 2500 Hassaka-cho, Hikone, Shiga, 522-8533, Japan
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Geremew A, Woldemariam MG, Kefalew A, Stiers I, Triest L. Isotropic and anisotropic processes influence fine-scale spatial genetic structure of a keystone tropical plant. AOB PLANTS 2018; 10:plx076. [PMID: 29383234 PMCID: PMC5777495 DOI: 10.1093/aobpla/plx076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 01/02/2018] [Indexed: 06/07/2023]
Abstract
Limited seed or pollen dispersal enhances spatial genetic relatedness between individuals (fine-scale spatial genetic structure, FSGS), which usually decreases as a function of physical distance. However, such isotropic pattern of FSGS may not always occur when spatially asymmetric processes, for instance, wind direction during dispersal, are considered in wind-pollinated and -dispersed plants. This study assessed the pattern of FSGS in the keystone tropical wetland plant Cyperus papyrus (papyrus) as a function of these isotropic and anisotropic processes. We tested the hypothesis that the FSGS would be influenced by predominant wind direction during pollen and seed dispersal, as well as by the physical distance between individuals. We genotyped a total of 510 adults and 407 juveniles from three papyrus swamps (Ethiopia) using 15 microsatellite markers. In addition, the contemporary directional dispersal by wind was evaluated by seed release-recapture experiments and complemented with parentage analysis. Adults and juveniles differed in the strength of isotropic FSGS ranging from 0.09 to 0.13 and 0.12 to 0.16, respectively, and this suggests variation in dispersal distance. Anisotropic FSGS was found to be a function of asymmetric wind direction during dispersal/pollination that varied between sites. Historical gene dispersal distance was astoundingly low (<4 m), possibly due to localized seed rain. According to our contemporary dispersal estimates, mean pollen dispersal distances were longer than those of seed dispersal (101 and <55 m, respectively). More than two-thirds of seeds and half of pollen grains were locally dispersed (≤80 m). The difference in historical and contemporary dispersal distance probably resulted from the asymmetric wind direction due to change in vegetation cover in the surrounding matrix. We further concluded that, in addition to wind direction, post-dispersal processes could influence gene dispersal distance inferred from the FSGS.
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Affiliation(s)
- Addisie Geremew
- Department of Biology, Vrije Universiteit Brussel (VUB), Pleinlaan,Brussels, Belgium
| | | | - Alemayehu Kefalew
- Department of Plant Biology and Biodiversity Management, College of Natural Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Iris Stiers
- Department of Biology, Vrije Universiteit Brussel (VUB), Pleinlaan,Brussels, Belgium
| | - Ludwig Triest
- Department of Biology, Vrije Universiteit Brussel (VUB), Pleinlaan,Brussels, Belgium
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Genetic diversity and structure of remnant Magnolia stellata populations affected by anthropogenic pressures and a conservation strategy for maintaining their current genetic diversity. CONSERV GENET 2016. [DOI: 10.1007/s10592-016-0817-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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10
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Thinning operations increase the demographic performance of the rare subtree species Magnolia stellata in a suburban forest landscape. LANDSCAPE AND ECOLOGICAL ENGINEERING 2015. [DOI: 10.1007/s11355-015-0281-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Chen L, Chen F, He S, Ma L. High genetic diversity and small genetic variation among populations of Magnolia wufengensis (Magnoliaceae), revealed by ISSR and SRAP markers. ELECTRON J BIOTECHN 2014. [DOI: 10.1016/j.ejbt.2014.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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