1
|
Beltrán LC, Martínez‐Garza C, Howe HF. Return of forest structure and diversity in tropical restoration plantings. Ecosphere 2022. [DOI: 10.1002/ecs2.4099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Luis Carlos Beltrán
- Department of Biological Sciences University of Illinois at Chicago Chicago Illinois USA
| | - Cristina Martínez‐Garza
- Centro de Investigación en Biodiversidad y Conservación Universidad Autónoma del Estado de Morelos Cuernavaca Mexico
| | - Henry F. Howe
- Department of Biological Sciences University of Illinois at Chicago Chicago Illinois USA
| |
Collapse
|
2
|
Marques Dracxler C, Kissling WD. The mutualism-antagonism continuum in Neotropical palm-frugivore interactions: from interaction outcomes to ecosystem dynamics. Biol Rev Camb Philos Soc 2021; 97:527-553. [PMID: 34725900 PMCID: PMC9297963 DOI: 10.1111/brv.12809] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 10/14/2021] [Accepted: 10/18/2021] [Indexed: 01/04/2023]
Abstract
Frugivory, that is feeding on fruits, pulp or seeds by animals, is usually considered a mutualism when interactions involve seed dispersal, and an antagonism when it results in the predation and destruction of seeds. Nevertheless, most frugivory interactions involve both benefits and disadvantages for plants, and the net interaction outcomes thus tend to vary along a continuum from mutualism to antagonism. Quantifying outcome variation is challenging and the ecological contribution of frugivorous animals to plant demography thus remains little explored. This is particularly true for interactions in which animals do not ingest entire fruits, that is in seed‐eating and pulp‐eating. Here, we provide a comprehensive review of Neotropical palm–frugivore interactions, with a focus on how frugivore consumption behaviour (i.e. digestive processing, fruit‐handling ability and caching behaviour) and feeding types (fruit‐eating, pulp‐eating and seed‐eating) influence interaction outcomes at different demographic stages of palms. We compiled a total of 1043 species‐level palm–frugivore interaction records that explicitly captured information on which parts of palm fruits are eaten by animals. These records showed consumption of fruits of 106 Neotropical palm species by 273 vertebrate species, especially birds (50%) and mammals (45%), but also fish (3%) and reptiles (2%). Fruit‐eating involved all four taxonomic vertebrate classes whereas seed‐eating and pulp‐eating were only recorded among birds and mammals. Most fruit‐eating interactions (77%) resulted in positive interaction outcomes for plants (e.g. gut‐passed seeds are viable or seeds are successfully dispersed), regardless of the digestive processing type of vertebrate consumers (seed defecation versus regurgitation). The majority of pulp‐eating interactions (91%) also resulted in positive interaction outcomes, for instance via pulp removal that promoted seed germination or via dispersal of intact palm seeds by external transport, especially if animals have a good fruit‐handling ability (e.g. primates, and some parrots). By contrast, seed‐eating interactions mostly resulted in dual outcomes (60%), where interactions had both negative effects on seed survival and positive outcomes through seed caching and external (non‐digestive) seed dispersal. A detailed synthesis of available field studies with qualitative and quantitative information provided evidence that 12 families and 27 species of mammals and birds are predominantly on the mutualistic side of the continuum whereas five mammalian families, six mammal and one reptile species are on the antagonistic side. The synthesis also revealed that most species can act as partial mutualists, even if they are typically considered antagonists. Our review demonstrates how different consumption behaviours and feeding types of vertebrate fruit consumers can influence seed dispersal and regeneration of palms, and thus ultimately affect the structure and functioning of tropical ecosystems. Variation in feeding types of animal consumers will influence ecosystem dynamics via effects on plant population dynamics and differences in long‐distance seed dispersal, and may subsequently affect ecosystem functions such as carbon storage. The quantification of intra‐ and inter‐specific variation in outcomes of plant–frugivore interactions – and their positive and negative effects on the seed‐to‐seedling transition of animal‐dispersed plants – should be a key research focus to understand better the mutualism–antagonism continuum and its importance for ecosystem dynamics.
Collapse
Affiliation(s)
- Caroline Marques Dracxler
- Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, P.O. Box 94240, Amsterdam, 1090 GE, The Netherlands
| | - W Daniel Kissling
- Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, P.O. Box 94240, Amsterdam, 1090 GE, The Netherlands
| |
Collapse
|
3
|
Jiménez-Lobato V, Núñez-Farfán J. Mating system of Datura inoxia: association between selfing rates and herkogamy within populations. PeerJ 2021; 9:e10698. [PMID: 33777507 PMCID: PMC7983856 DOI: 10.7717/peerj.10698] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 12/13/2020] [Indexed: 11/20/2022] Open
Abstract
Plant mating system determines, to a great extent, the demographic and genetic properties of populations, hence their potential for adaptive evolution. Variation in plant mating system has been documented between phylogenetically related species as well between populations of a species. A common evolutionary transition, from outcrossing to selfing, is likely to occur under environmental spatial variation in the service of pollinators. Here, we studied two phenotypically (in floral traits) and genetically (in neutral molecular markers) differentiated populations of the annual, insect-pollinated, plant Datura inoxia in Mexico, that differ in the service of pollinators (Mapimí and Cañada Moreno). First, we determined the populations’ parameters of phenotypic in herkogamy, outcrossing and selfing rates with microsatellite loci, and assessed between generation (adults and seedlings) inbreeding, and inbreeding depression. Second, we compared the relationships between parameters in each population. Results point strong differences between populations: plants in Mapimí have, on average, approach herkogamy, higher outcrossing rate (tm = 0.68), lower primary selfing rate (r = 0.35), and lower inbreeding at equilibrium (Fe = 0.24) and higher inbreeding depression (δ = 0.25), than the populations of Cañada. Outcrossing seems to be favored in Mapimí while selfing in Cañada. The relationship between r and Fe were negatively associated with herkogamy in Mapimí; here, progenies derived from plants with no herkogamy or reverse herkogamy had higher selfing rate and inbreeding coefficient than plants with approach herkogamy. The difference Fe–F is positively related to primary selfing rate (r) only in Cañada Moreno which suggests inbreeding depression in selfing individuals and then genetic purging. In conclusion, mating system evolution may occur differentially among maternal lineages within populations of Datura inoxia, in which approach herkogamy favors higher outcrossing rates and low levels of inbreeding and inbreeding depression, while no herkogamy or reverse herkogamy lead to the evolution of the “selfing syndrome” following the purge of deleterious alleles despite high inbreeding among individuals.
Collapse
Affiliation(s)
- Vania Jiménez-Lobato
- Escuela Superior de Desarrollo Sustentable, Universidad Autónoma de Guerrero, Cátedras CONACYT, México.,Laboratorio de Genética Ecológica y Evolución, Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Distrito Federal, Mexico
| | - Juan Núñez-Farfán
- Laboratorio de Genética Ecológica y Evolución, Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Distrito Federal, Mexico
| |
Collapse
|
4
|
Montúfar R, Recalde A, Couvreur TLP. High genetic diversity with low connectivity among
Mauritia flexuosa
(Arecaceae) stands from Ecuadorean Amazonia. Biotropica 2020. [DOI: 10.1111/btp.12855] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rommel Montúfar
- Facultad de Ciencias Exactas y Naturales Pontificia Universidad Católica del Ecuador Quito Ecuador
| | - Andrés Recalde
- Facultad de Ciencias Exactas y Naturales Pontificia Universidad Católica del Ecuador Quito Ecuador
| | - Thomas L. P. Couvreur
- Facultad de Ciencias Exactas y Naturales Pontificia Universidad Católica del Ecuador Quito Ecuador
- IRD, DIADE Univ Montpellier Montpellier France
| |
Collapse
|
5
|
Battey CJ, Ralph PL, Kern AD. Space is the Place: Effects of Continuous Spatial Structure on Analysis of Population Genetic Data. Genetics 2020; 215:193-214. [PMID: 32209569 PMCID: PMC7198281 DOI: 10.1534/genetics.120.303143] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 03/12/2020] [Indexed: 12/14/2022] Open
Abstract
Real geography is continuous, but standard models in population genetics are based on discrete, well-mixed populations. As a result, many methods of analyzing genetic data assume that samples are a random draw from a well-mixed population, but are applied to clustered samples from populations that are structured clinally over space. Here, we use simulations of populations living in continuous geography to study the impacts of dispersal and sampling strategy on population genetic summary statistics, demographic inference, and genome-wide association studies (GWAS). We find that most common summary statistics have distributions that differ substantially from those seen in well-mixed populations, especially when Wright's neighborhood size is < 100 and sampling is spatially clustered. "Stepping-stone" models reproduce some of these effects, but discretizing the landscape introduces artifacts that in some cases are exacerbated at higher resolutions. The combination of low dispersal and clustered sampling causes demographic inference from the site frequency spectrum to infer more turbulent demographic histories, but averaged results across multiple simulations revealed surprisingly little systematic bias. We also show that the combination of spatially autocorrelated environments and limited dispersal causes GWAS to identify spurious signals of genetic association with purely environmentally determined phenotypes, and that this bias is only partially corrected by regressing out principal components of ancestry. Last, we discuss the relevance of our simulation results for inference from genetic variation in real organisms.
Collapse
Affiliation(s)
- C J Battey
- Institute of Ecology Evolution, Department of Biology, University of Oregon, Eugene, Oregon
| | - Peter L Ralph
- Institute of Ecology Evolution, Department of Biology, University of Oregon, Eugene, Oregon
| | - Andrew D Kern
- Institute of Ecology Evolution, Department of Biology, University of Oregon, Eugene, Oregon
| |
Collapse
|
6
|
Santos JD, Varassin IG, Muschner VC, Ovaskainen O. Estimating seed and pollen dispersal kernels from genetic data demonstrates a high pollen dispersal capacity for an endangered palm species. AMERICAN JOURNAL OF BOTANY 2018; 105:1802-1812. [PMID: 30347429 DOI: 10.1002/ajb2.1176] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 08/08/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Seed and pollen dispersal are key processes shaping plant population dynamics and maintaining genetic diversity. The essence of these processes is the movement of propagules from a parental tree to the site of propagule establishment. The estimation of plant dispersal kernels has remained challenging due to the difficulty of making direct observations. We estimated the dispersal capacity of the endangered palm Euterpe edulis, whose seeds are dispersed by vertebrates and pollen by insects. METHODS We used a hierarchical Bayesian model with genetic data from reproductive plants, juveniles, and embryos to estimate dispersal kernels. Our analyses account for genotyping error and uncertainty in parental assignment. KEY RESULTS We found that seeds were dispersed at most a few hundred meters, but pollen was dispersed up to several kilometers. We hypothesize that this long-distance pollen dispersal is generated mainly by euglossine bees, whereas the main dispersal vectors for short-distance seed dispersal are thrushes. The long-distance dispersal of pollen suggests a high level of gene flow that should maintain genetic diversity of E. edulis. Despite the relation between long-distance dispersal and genetic diversity, we observed low genetic diversity and inbreeding within the local population, which are probably due to restricted gene flow due to the low density of this population and its aggregated spatial distribution. CONCLUSIONS We conclude that if conservation actions are able to restore the population density of E. edulis, the recovery of its genetic diversity will be facilitated because of its high dispersal capacity, especially with regard to pollen.
Collapse
Affiliation(s)
- Jaqueline Dos Santos
- Laboratório de Ecologia Molecular Vegetal, Departamento de Botânica, Setor de Ciências Biológicas, Centro Politécnico, Universidade Federal do Paraná, Caixa Postal 19031, CEP: 81531-990, Curitiba, PR, Brazil
- Laboratório de Interações e Biologia Reprodutiva, Departamento de Botânica, Setor de Ciências Biológicas, Centro Politécnico, Universidade Federal do Paraná, Caixa Postal 19031, CEP: 81531-990, Curitiba, PR, Brazil
- Programa de Pós-Graduação em Ecologia e Conservação - UFPR
| | - Isabela Galarda Varassin
- Laboratório de Interações e Biologia Reprodutiva, Departamento de Botânica, Setor de Ciências Biológicas, Centro Politécnico, Universidade Federal do Paraná, Caixa Postal 19031, CEP: 81531-990, Curitiba, PR, Brazil
- Programa de Pós-Graduação em Ecologia e Conservação - UFPR
| | - Valéria Cunha Muschner
- Laboratório de Ecologia Molecular Vegetal, Departamento de Botânica, Setor de Ciências Biológicas, Centro Politécnico, Universidade Federal do Paraná, Caixa Postal 19031, CEP: 81531-990, Curitiba, PR, Brazil
- Programa de Pós-Graduação em Ecologia e Conservação - UFPR
| | - Otso Ovaskainen
- Department of Biosciences, University of Helsinki, Viikinkaari 1, Helsinki, 00014, Finland
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, N-7491, Trondheim, Norway
| |
Collapse
|
7
|
Hernández-Ruedas MA, Arroyo-Rodríguez V, Morante-Filho JC, Meave JA, Martínez-Ramos M. Fragmentation and matrix contrast favor understory plants through negative cascading effects on a strong competitor palm. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:1546-1553. [PMID: 29727519 DOI: 10.1002/eap.1740] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 02/27/2018] [Accepted: 04/06/2018] [Indexed: 06/08/2023]
Abstract
Understanding the patterns and processes driving biodiversity maintenance in fragmented tropical forests is urgently needed for conservation planning, especially in species-rich forest reserves. Of particular concern are the effects that habitat modifications at the landscape scale may have on forest regeneration and ecosystem functioning: a topic that has received limited attention. Here, we assessed the effects of landscape structure (i.e., forest cover, open area matrices, forest fragmentation, and mean inter-patch isolation distance) on understory plant assemblages in the Los Tuxtlas Biosphere Reserve, Mexico. Previous studies suggest that the demographic burst of the strong competitor palm Astrocaryum mexicanum in the core area of this reserve limits plant recruitment and imperils biodiversity conservation within this protected area. Yet, the local and landscape predictors of this palm, and its impact on tree recruitment at a regional scale are unknown. Thus, we used structural equation modeling to assess the direct and cascading effects of landscape structure on stem and species density in the understory of 20 forest sites distributed across this biodiversity hotspot. Indirect paths included the effect of landscape structure on tree basal area (a proxy of local disturbance), and the effects of these variables on A. mexicanum. Density of A. mexicanum mainly increased with decreasing both fragmentation and open areas in the matrix (matrix contrast, hereafter), and such an increase in palm density negatively affected stem and species density in the understory. The negative direct effect of matrix contrast on stem density was overridden by the indirect positive effects (i.e., through negative cascading effects on A. mexicanum), resulting in a weak effect of matrix contrast on stem density. These findings suggest that dispersal limitation and negative edge effects in more fragmented landscapes dominated by open areas prevent the proliferation of this palm species, enhancing the diversity and abundance of understory trees. This "positive" news adds to an increasing line of evidence suggesting that fragmentation may have some positive effects on biodiversity, in this case by preventing the proliferation of species that can jeopardize biodiversity conservation within tropical reserves.
Collapse
Affiliation(s)
- Manuel A Hernández-Ruedas
- Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro 8701, Ex-Hacienda de San José de La Huerta, Morelia, 58190, Michoacán, Mexico
| | - Víctor Arroyo-Rodríguez
- Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro 8701, Ex-Hacienda de San José de La Huerta, Morelia, 58190, Michoacán, Mexico
| | - José Carlos Morante-Filho
- Applied Conservation Ecology Lab, Universidade Estadual de Santa Cruz, Rodovia Ilhéus-Itabuna, km 16, Salobrinho, Ilhéus, 45662-000, Bahia, Brazil
| | - Jorge A Meave
- Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Av. Universidad 3000, Circuito Exterior S/N, Coyoacán, Mexico City, 04510, Mexico
| | - Miguel Martínez-Ramos
- Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro 8701, Ex-Hacienda de San José de La Huerta, Morelia, 58190, Michoacán, Mexico
| |
Collapse
|
8
|
Ruckelshaus MH. ESTIMATION OF GENETIC NEIGHBORHOOD PARAMETERS FROM POLLEN AND SEED DISPERSAL IN THE MARINE ANGIOSPERM
ZOSTERA MARINA
L. Evolution 2017; 50:856-864. [DOI: 10.1111/j.1558-5646.1996.tb03894.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/1994] [Accepted: 03/24/1995] [Indexed: 11/27/2022]
Affiliation(s)
- Mary H. Ruckelshaus
- Department of Botany, KB‐15 University of Washington Seattle Washington 98195
| |
Collapse
|
9
|
Alvarez-Buylla ER, Garay AA. POPULATION GENETIC STRUCTURE OF CECROPIA OBTUSIFOLIA, A TROPICAL PIONEER TREE SPECIES. Evolution 2017; 48:437-453. [PMID: 28568300 DOI: 10.1111/j.1558-5646.1994.tb01322.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/1992] [Accepted: 06/28/1993] [Indexed: 11/27/2022]
Abstract
Theoretical analyses of the genetic organization of pioneer species have postulated two very different scenarios. Some models have predicted that such species would show strong population substructuring, whereas other models have suggested that extinction and recolonization can augment gene flow and reduce interpopulation differentiation. We tested these alternative scenarios by analyzing the genetic structure of eight loci from populations of the pioneer dioecious tree, Cecropia obtusifolia, in the tropical rain forest region of Los Tuxtlas, México. The populations studied exhibit low overall FST values, no clear pattern of isolation by distance, and high estimates of gene flow. These results suggest either that the species is not at a genetic equilibrium under present levels of gene flow with populations derived from each other in the recent past, or that pollen and seed dispersal in this species occur over long distances (up to more than 100 km). Mating among relatives appears higher than expected by chance based on significantly positive fixation indices (F) and FIS values at some loci. However, no direct evidence for biparental inbreeding was found. The multilocus and single-locus outcrossing rates for C. obtusifolia were estimated at tm = 0.974 (SE = 0.024) and ts = 0.980 (SE = 0.035), respectively. These are not significantly different from 1, and the difference, tm - ts = - 0.006 (SE = 0.018), is not significantly different from 0. These estimates, however, could be biased because in all enzymes, except PGM-1, we found statistically significant departures from the mixed-mating model used to estimate them. Two rare alleles were found only in seeds collected from the soil, and the greatest number of different alleles were found also in soil seeds. It is hypothesized that the seed bank may play an important role in the genetic buffering of C. obtusifolia. Significantly positive or negative fixation indices in adults at some loci and significantly different heterozygosities among different life stages (from seeds to adults) suggest the action of selection at some loci.
Collapse
Affiliation(s)
- Elena R Alvarez-Buylla
- Centro de Ecología, Universidad Nacional Autónoma de México, Aptado. Postal 70-275, México D.F., 04510, México
| | - Adriana A Garay
- Centro de Ecología, Universidad Nacional Autónoma de México, Aptado. Postal 70-275, México D.F., 04510, México
| |
Collapse
|
10
|
Assunção R, Jacobi CM. OPTIMAL SAMPLING DESIGN FOR STUDIES OF GENE FLOW FROM A POINT SOURCE USING MARKER GENES OR MARKED INDIVIDUALS. Evolution 2017; 50:918-923. [DOI: 10.1111/j.1558-5646.1996.tb03901.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/1994] [Accepted: 03/29/1995] [Indexed: 11/29/2022]
Affiliation(s)
- Renato Assunção
- Departamento de Estatística; UFMG; C.P. 702 30161-970 Belo Horizonte Minas Gerais Brazil
| | - Claudia M. Jacobi
- Department of Zoology; University of Washington; Box 351800 Seattle Washington 98195
| |
Collapse
|
11
|
Nunney L. The effect of neighborhood size on effective population size in theory and in practice. Heredity (Edinb) 2016; 117:224-32. [PMID: 27553453 PMCID: PMC5026762 DOI: 10.1038/hdy.2016.76] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 07/07/2016] [Accepted: 07/15/2016] [Indexed: 11/09/2022] Open
Abstract
The distinction between the effective size of a population (Ne) and the effective size of its neighborhoods (Nn) has sometimes become blurred. Ne reflects the effect of random sampling on the genetic composition of a population of size N, whereas Nn is a measure of within-population spatial genetic structure and depends strongly on the dispersal characteristics of a species. Although Nn is independent of Ne, the reverse is not true. Using simulations of a population of annual plants, it was found that the effect of Nn on Ne was well approximated by Ne=N/(1-FIS), where FIS (determined by Nn) was evaluated population wide. Nn only had a notable influence of increasing Ne as it became smaller (⩽16). In contrast, the effect of Nn on genetic estimates of Ne was substantial. Using the temporal method (a standard two-sample approach) based on 1000 single-nucleotide polymorphisms (SNPs), and varying sampling method, sample size (2-25% of N) and interval between samples (T=1-32 generations), estimates of Ne ranged from infinity to <0.1% of the true value (defined as Ne based on 100% sampling). Estimates were never accurate unless Nn and T were large. Three sampling techniques were tested: same-site resampling, different-site resampling and random sampling. Random sampling was the least biased method. Extremely low estimates often resulted when different-site resampling was used, especially when the population was large and the sample fraction was small, raising the possibility that this estimation bias could be a factor determining some very low Ne/N that have been published.
Collapse
Affiliation(s)
- L Nunney
- Department of Biology, University of California, Riverside, Riverside, CA, USA
| |
Collapse
|
12
|
Ramos SLF, Dequigiovanni G, Sebbenn AM, Lopes MTG, Kageyama PY, de Macêdo JLV, Kirst M, Veasey EA. Spatial genetic structure, genetic diversity and pollen dispersal in a harvested population of Astrocaryum aculeatum in the Brazilian Amazon. BMC Genet 2016; 17:63. [PMID: 27108235 PMCID: PMC4842287 DOI: 10.1186/s12863-016-0371-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 04/15/2016] [Indexed: 11/13/2022] Open
Abstract
Background Astrocaryum aculeatum is a palm tree species native to the tropical regions of South America, exploited commercially by local farmers for the pulp extracted from its fruits. The objective of this research was to compare the genetic diversity between adult plants and seedlings from open-pollinated seeds, quantify the pollen flow and dispersal, the spatial genetic structure, and the effective size of a population that has been continuously harvested for its fruits. The study was carried out in a natural population of A. aculeatum distributed over approximately 8 ha in the State of Amazonas (Brazil), separated by 400 m from the closest neighboring population. In total, 112 potential pollen donors, 12 mother plants and 120 offspring were mapped and genotyped. Results Genetic diversity was high for parents and the offspring. The fixation indexes for adults (F = -0.035) and offspring (F = -0.060) were negative and not significant. A significant spatial genetic structure was detected for the adult plants (up to the distance of 45 m) indicating short-distance seed dispersal. Paternity analysis detected 9.2 % of pollen immigration and the average distance of pollination within the population was 81 m. The average effective pollination neighborhood area between plants was 1.51 ha. Conclusions Our results indicate that substantial introduction of new alleles has occurred in the population through pollen immigration, contributing to the maintenance of genetic diversity. Conservation efforts aimed at maintaining the gene pool of the current population or establishing new populations should utilize offspring from mother plants selected to be spaced by at least 50 m to prevent collecting seeds from relatives.
Collapse
Affiliation(s)
- Santiago Linorio Ferreyra Ramos
- Escola Superior de Agricultura "Luiz de Queiroz"/Universidade de São Paulo (ESALQ/USP), Departamento de Genética, C.P. 9, CEP 13418-900, Av. Pádua Dias, 11, Piracicaba, SP, Brazil.
| | - Gabriel Dequigiovanni
- Escola Superior de Agricultura "Luiz de Queiroz"/Universidade de São Paulo (ESALQ/USP), Departamento de Genética, C.P. 9, CEP 13418-900, Av. Pádua Dias, 11, Piracicaba, SP, Brazil
| | - Alexandre Magno Sebbenn
- Instituto Florestal de São Paulo, Seção de Melhoramento e Conservação Genética Florestal, C.P. 1322, CEP 01059-970, São Paulo, SP, Brazil
| | - Maria Teresa Gomes Lopes
- Faculdade de Ciências Agrárias, Universidade Federal do Amazonas (UFAM), CEP 60077-000, Manaus, AM, Brazil
| | - Paulo Yoshio Kageyama
- ESALQ/USP, Departamento de Ciências Florestais, Av. Pádua Dias, 11, C.P. 9, CEP 13418-900, Piracicaba, SP, Brazil
| | | | - Matias Kirst
- University of Florida, School of Forest Resources & Conservation, PO Box 110410, Gainesville, FL, 32611-0410, USA
| | - Elizabeth Ann Veasey
- Escola Superior de Agricultura "Luiz de Queiroz"/Universidade de São Paulo (ESALQ/USP), Departamento de Genética, C.P. 9, CEP 13418-900, Av. Pádua Dias, 11, Piracicaba, SP, Brazil.
| |
Collapse
|
13
|
Anthropogenic disturbances jeopardize biodiversity conservation within tropical rainforest reserves. Proc Natl Acad Sci U S A 2016; 113:5323-8. [PMID: 27071122 DOI: 10.1073/pnas.1602893113] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Anthropogenic disturbances affecting tropical forest reserves have been documented, but their ecological long-term cumulative effects are poorly understood. Habitat fragmentation and defaunation are two major anthropogenic threats to the integrity of tropical reserves. Based on a long-term (four decades) study, we document how these disturbances synergistically disrupt ecological processes and imperil biodiversity conservation and ecosystem functioning at Los Tuxtlas, the northernmost tropical rainforest reserve in the Americas. Deforestation around this reserve has reduced the reserve to a medium-sized fragment (640 ha), leading to an increased frequency of canopy-gap formation. In addition, hunting and habitat loss have caused the decline or local extinction of medium and large herbivores. Combining empirical, experimental, and modeling approaches, we support the hypothesis that such disturbances produced a demographic explosion of the long-lived (≈120 y old, maximum height of 7 m) understory palm Astrocaryum mexicanum, whose population has increased from 1,243-4,058 adult individuals per hectare in only 39 y (annual growth rate of ca 3%). Faster gap formation increased understory light availability, enhancing seed production and the growth of immature palms, whereas release from mammalian herbivory and trampling increased survival of seedlings and juveniles. In turn, the palm's demographic explosion was followed by a reduction of tree species diversity, changing forest composition, altering the relative contribution of trees to forest biomass, and disrupting litterfall dynamics. We highlight how indirect anthropogenic disturbances (e.g., palm proliferation) on otherwise protected areas threaten tropical conservation, a phenomenon that is currently eroding the planet's richest repositories of biodiversity.
Collapse
|
14
|
Martinez-Ramos M, Alvarez-Buylla ER. Seed dispersal and patch dynamics in tropical rain forests: A demographic approach. ECOSCIENCE 2016. [DOI: 10.1080/11956860.1995.11682287] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
15
|
The pollen dispersal kernel and mating system of an insect-pollinated tropical palm, Oenocarpus bataua. Heredity (Edinb) 2012; 109:332-9. [PMID: 22892637 DOI: 10.1038/hdy.2012.40] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Pollen dispersal shapes the local genetic structure of plant populations and determines the opportunity for local selection and genetic drift, but has been well studied in few animal-pollinated plants in tropical rainforests. Here, we characterise pollen movement for an insect-pollinated Neotropical canopy palm, Oenocarpus bataua, and relate these data to adult mating system and population genetic structure. The study covers a 130-ha parcel in which all adult trees (n=185) were mapped and genotyped at 12 microsatellite loci, allowing us to positively identify the source tree for 90% of pollination events (n=287 of 318 events). Mating system analysis showed O. bataua was effectively outcrossed (t(m)=1.02) with little biparental inbreeding (t(m)-t(s)=-0.005) and an average of 5.4 effective pollen donors (N(ep)) per female. Dispersal distances were relatively large for an insect-pollinated species (mean=303 m, max=1263 m), and far exceeded nearest-neighbour distances. Dispersal kernel modelling indicated a thin-tailed Weibull distribution offered the best fit to the genetic data, which contrasts with the fat-tailed kernels typically reported for pollen dispersal in trees. Preliminary analyses suggest that our findings may be explained, at least in part, by a relatively diffuse spatial and temporal distribution of flowering trees. Comparison with previously reported estimates of seed movement for O. bataua suggests that pollen and seed dispersal distances may be similar. These findings add to the growing body of information on dispersal in insect-pollinated trees, but underscore the need for continued research on tropical systems in general, and palms in particular.
Collapse
|
16
|
Abstract
SummaryThe effective population size is required to predict the rate of inbreeding and loss of genetic variation in wildlife. Since only census population size is normally available, it is critical to know the ratio of effective to actual population size (Ne/N). Published estimates ofNe/N(192 from 102 species) were analysed to identify major variables affecting the ratio, and to obtain a comprehensive estimate of the ratio with all relevant variables included. The five most important variables explaining variation among estimates, in order of importance, were fluctuation in population size, variance in family size, form ofNused (adults υ. breeders υ. total size), taxonomic group and unequal sex-ratio. There were no significant effects on the ratio of high υ. low fecundity, demographic υ. genetic methods of estimation, or of overlapping υ. non-overlapping generations when the same variables were included in estimates. Comprehensive estimates ofNe/N(that included the effects of fluctuation in population size, variance in family size and unequal sex-ratio) averaged only 0·10–0·11. Wildlife populations have much smaller effective population sizes than previously recognized.
Collapse
|
17
|
Ravigné V, Olivieri I, Martinez SG, Rousset F. SELECTIVE INTERACTIONS BETWEEN SHORT-DISTANCE POLLEN AND SEED DISPERSAL IN SELF-COMPATIBLE SPECIES. Evolution 2006. [DOI: 10.1111/j.0014-3820.2006.tb01863.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
18
|
Mantovani A, Morellato LPC, Dos Reis MS. Internal genetic structure and outcrossing rate in a natural population of Araucaria angustifolia (Bert.) O. Kuntze. ACTA ACUST UNITED AC 2006; 97:466-72. [PMID: 16982668 DOI: 10.1093/jhered/esl031] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The internal genetic structure and outcrossing rate of a population of Araucaria angustifolia (Bert.) O. Kuntze were investigated using 16 allozyme loci. Estimates of the mean number of alleles per loci (1.6), percentage of polymorphic loci (43.8%), and expected genetic diversity (0.170) were similar to those obtained for other gymnosperms. The analysis of spatial autocorrelation demonstrated the presence of internal structure in the first distance classes (up to 70 m), suggesting the presence of family structure. The outcrossing rate was high (0.956), as expected for a dioecious species. However, it was different from unity, indicating outcrossings between related individuals and corroborating the presence of internal genetic structure. The results of this study have implications for the methodologies used in conservation collections and for the use or analysis of this forest species.
Collapse
Affiliation(s)
- Adelar Mantovani
- Departamento de Fitotecnia, Núcleo de Pesquisas em Florestas Tropicais, Universidade do Estado de Santa Catarina, 88520-000 Lages, Brazil.
| | | | | |
Collapse
|
19
|
Ravigné V, Olivieri I, González-Martínez SC, Rousset F. SELECTIVE INTERACTIONS BETWEEN SHORT-DISTANCE POLLEN AND SEED DISPERSAL IN SELF-COMPATIBLE SPECIES. Evolution 2006. [DOI: 10.1554/05-352.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
20
|
Degen B, Roubik DW. Effects of Animal Pollination on Pollen Dispersal, Selfing, and Effective Population Size of Tropical Trees: A Simulation Study. Biotropica 2004. [DOI: 10.1111/j.1744-7429.2004.tb00309.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
21
|
Degen B, Roubik DW. Effects of Animal Pollination on Pollen Dispersal, Selfing, and Effective Population Size of Tropical Trees: A Simulation Study1. Biotropica 2004. [DOI: 10.1646/q1554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
22
|
Silva-Montellano A, Eguiarte LE. Geographic patterns in the reproductive ecology of Agave lechuguilla (Agavaceae) in the Chihuahuan desert. II. Genetic variation, differentiation, and inbreeding estimates. AMERICAN JOURNAL OF BOTANY 2003; 90:700-706. [PMID: 21659165 DOI: 10.3732/ajb.90.5.700] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Plants with natural variation in their floral traits and reproductive ecology are ideal subjects for analyzing the effects of natural selection and other evolutionary forces on genetic structure of natural populations. Agave lechuguilla shows latitudinal changes in floral morphology, color, and nectar production along its distribution through north-central Mexico. Both the type and abundance of its pollinators also change with latitude. Using starch electrophoresis, we examined the levels and patterns of variation of 13 polymorphic allozyme loci in 11 populations of A. lechuguilla. The overall level of genetic variability was high (H(e) = 0.394), but the levels of genetic variation had no geographic pattern. However, the southern populations exhibited an excess of heterozygotes in relation to expectations for Hardy-Weinberg equilibrium, whereas the northern populations had an excess of homozygotes. Total differentiation among populations was low (θ = 0.083), although gene flow estimates (Nm) varied among groups of populations: southern populations had the lowest levels of genetic differentiation, suggesting high levels of gene flow; northern populations had greater levels of genetic differentiation (θ = 0.115), suggesting low gene flow among them. The patterns and inferences of the genetic structure of the population at the molecular level is consistent with variation in floral traits and pollinator visitation rates across the range of the species.
Collapse
Affiliation(s)
- Arturo Silva-Montellano
- Departamento de Ecología Evolutiva, Instituto de Ecología, Apartado postal 70-275, C.U., Universidad Nacional Autónoma de Mexico, CP 04510, D.F., Mexico
| | | |
Collapse
|
23
|
Navarro-Quezada A, González-Chauvet R, Molina-Freaner F, Eguiarte LE. Genetic differentiation in the Agave deserti (Agavaceae) complex of the Sonoran desert. Heredity (Edinb) 2003; 90:220-7. [PMID: 12634805 DOI: 10.1038/sj.hdy.6800216] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The Agave deserti complex, comprising A. deserti, A. cerulata and A. subsimplex, represents a group of species and subspecies with a near allopatric distribution and clear differences in morphology. Genetic differentiation and taxonomic status with respect to spatial distribution of 14 populations of the complex were analyzed in an effort to understand the evolution and speciation process within the genus. Allelic frequencies, levels of genetic variation, expected heterozygosity (H(S)), proportion of polymorphic loci (P), and genetic differentiation (theta and Nei's genetic distance) were estimated using 41 putative RAPD loci. All three species show high levels of genetic variation (H(S)=0.12-0.29, P=63.4-95.1), and low genetic differentiation between populations and species (theta populations=0.14+/-0.02 (SE); G(st)=0.11+/-0.02). Accordingly, gene flow among populations was estimated as high by three different methods (N(m)=2.91-6.14). Nei's genetic distances between the three species were low compared to the values obtained from other Agavaceae, and there was no clear correlation with taxonomic divisions. In a UPGMA analysis, A. subsimplex and A. cerulata formed exclusive monospecific clusters, whereas the A. deserti populations appear in more than one cluster together with other species. The results were consistent with a pattern of genetic isolation by distance.
Collapse
Affiliation(s)
- A Navarro-Quezada
- Biology Department, McGill University, 1205 Avenue Dr. Penfield, Montreal, Quebec, Canada H3A 1B1.
| | | | | | | |
Collapse
|
24
|
Dodd ME, Silvertown J. Size-specific fecundity and the influence of lifetime size variation upon effective population size in Abies balsamea. Heredity (Edinb) 2000; 85:604-9. [PMID: 11240627 DOI: 10.1046/j.1365-2540.2000.00822.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The hierarchy of plant size often present in dense populations of plants and the close correlation found between size and fecundity can result in an unequal distribution of fecundity, which reduces the ratio of effective population size/census number (Ne/N). Such an effect has been found previously in annuals, but no study has hitherto tested for the effect in the lifetime fecundity variation of a perennial population. We use the demographically stable size distribution to be found in natural, wave-regenerating populations of balsam fir, Abies balsamea, in order to estimate Ne/N. In both wave-regenerating and normal forests our estimated values of Ne/N were about twice those previously reported for annuals. We suggest that fecundity variance is expected to be smaller in trees and other long-lived perennials than in annuals because density-dependent mortality operates more strongly in the prereproductive phase of long-lived plants.
Collapse
Affiliation(s)
- M E Dodd
- Ecology and Evolution Research Group, Department of Biological Sciences, Open University, Milton Keynes MK7 6AA, UK
| | | |
Collapse
|
25
|
Fetched N, Cordero RA, Voltzow J. Lack of Ecotypic Differentiation: Plant Response to Elevation, Population Origin, and Wind in the Luquillo Mountains, Puerto Rico1. Biotropica 2000. [DOI: 10.1111/j.1744-7429.2000.tb00465.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
26
|
Fetcher N, Cordero RA, Voltzow J. Lack of Ecotypic Differentiation: Plant Response to Elevation, Population Origin, and Wind in the Luquillo Mountains, Puerto Rico1. Biotropica 2000. [DOI: 10.1646/0006-3606(2000)032[0225:loedpr]2.0.co;2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
27
|
Tremblay RL. Distribution and Dispersion Patterns of Individuals in Nine Species of Lepanfhes (Orchidaceae)1. Biotropica 1997. [DOI: 10.1111/j.1744-7429.1997.tb00004.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
28
|
Neighbourhood size and the importance of barriers to gene flow in an intertidal snail. Heredity (Edinb) 1995. [DOI: 10.1038/hdy.1995.117] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
|
29
|
Gallardo MH, Köhler N, Araneda C. Bottleneck effects in local populations of fossorial Ctenomys (Rodentia, Ctenomyidae) affected by vulcanism. Heredity (Edinb) 1995. [DOI: 10.1038/hdy.1995.87] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
|
30
|
Seed dispersal in Erythronium grandiflorum (Liliaceae). Oecologia 1995; 102:211-219. [DOI: 10.1007/bf00333253] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/1994] [Accepted: 11/29/1994] [Indexed: 10/26/2022]
|
31
|
Krauss SL. Restricted gene flow within the morphologically complex species Persoonia mollis (Proteaceae): contrasting evidence from the mating system and pollen dispersal. Heredity (Edinb) 1994. [DOI: 10.1038/hdy.1994.113] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
|