scholarly journals Patterns of Effective Pollen Dispersal in Larch: Linking Levels of Background Pollination with Pollen Dispersal Kernels

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1139 ◽  
Author(s):  
Jarosław Burczyk ◽  
Elżbieta Sandurska ◽  
Andrzej Lewandowski
Keyword(s):  
Pollen Dispersal ◽  
Natural Populations ◽  
Real Data ◽  
Forest Tree ◽  
Adult Trees ◽  
Self Fertilization ◽  
Świętokrzyski National Park ◽  
Exponential Power ◽  
Reproductive Processes ◽  
Dispersal Kernels

Monitoring patterns of mating and pollen dispersal in forest tree populations subjected to nature conservation is essential to understanding the dynamics of their reproductive processes and might be helpful in making management decisions aimed at conserving genetic diversity and integrity over the long term. However, little is known about effective pollen dispersal in natural populations of conifers, particularly in subdominant species such as larch. We investigated patterns of pollen dispersal in the Polish larch population of Świętokrzyski National Park. The studied population was located on Chełmowa Mountain in a forest complex 160 ha in size, which is relatively isolated from other forest stands. We assessed if local pollen dispersal inferred from pollen dispersal kernels could provide indications of the level of background pollination from sources located outside of the forest complex. The analysis focused on two plots, each encompassing 126 adult trees, and seed samples (n = 600) collected from 20 trees. Using 11 nuclear microsatellites and spatially explicit mating models, we identified details of mating patterns. The rate of self-fertilization was low (0.0268). Background pollination was moderate (0.4058), and the mean pollen dispersal was found to be 167 m and 111 m, based on exponential-power and Weibull dispersal kernels, respectively. Specific simulations performed based on the estimated pollen dispersal kernels provided background pollination levels comparable to those observed for real data, suggesting that the pollen contributing to background pollination likely originated from the studied forest complex and not from other surrounding populations. These results confirm the high potential for maintaining the genetic integrity of the larch population and support efforts aimed at promoting regeneration of the stands, either natural or through the artificial planting of seedlings derived from trees growing in the core larch population of the protected area.

Update on the Boundaries of the Curly Birch Range

2020 ◽  
pp. 9-21
Author(s):  
L.V. Vetchinnikova ◽  
◽  
A.F. Titov ◽  
◽  
Keyword(s):  
Population Size ◽  
Natural Populations ◽  
Forest Tree ◽  
Published Data ◽  
Population Approach ◽  
Key Factors ◽  
History Of ◽  
Individual Trees ◽  
Karelian Birch

The article reports on the application of the best known principles for mapping natural populations of curly (Karelian) birch Betula pendula Roth var. carelica (Mercklin) Hämet-Ahti – one of the most appealing representatives of the forest tree flora. Relying on the synthesis and analysis of the published data amassed over nearly 100 years and the data from own full-scale studies done in the past few decades almost throughout the area where curly birch has grown naturally, it is concluded that its range outlined in the middle of the 20th century and since then hardly revised is outdated. The key factors and reasons necessitating its revision are specified. Herewith it is suggested that the range is delineated using the population approach, and the key element will be the critical population size below which the population is no longer viable in the long term. This approach implies that the boundaries of the taxon range depend on the boundaries of local populations (rather than the locations of individual trees or small clumps of trees), the size of which should not be lower than the critical value, which is supposed to be around 100–500 trees for curly birch. A schematic map of the curly birch range delineated using this approach is provided. We specially address the problem of determining the minimum population size to secure genetic diversity maintenance. The advantages of the population approach to delineating the distribution range of curly birch with regard to its biological features are highlighted. The authors argue that it enables a more accurate delineation of the range; shows the natural evolutionary history of the taxon (although it is not yet officially recognized as a species) and its range; can be relatively easily updated (e.g. depending on the scope of reintroduction); should be taken into account when working on the strategy of conservation and other actions designed to maintain and regenerate this unique representative of the forest tree flora.

Spatial genetic substructure within natural populations of jack pine (Pinus banksiana)

1991 ◽  
Vol 69 (3) ◽  
pp. 547-551 ◽  
Author(s):  
Chang Yi Xie ◽  
Peggy Knowles
Keyword(s):  
Spatial Autocorrelation ◽  
Pinus Banksiana ◽  
Pollen Dispersal ◽  
Natural Populations ◽  
Jack Pine ◽  
Spatial Autocorrelation Analysis ◽  
Autocorrelation Analysis ◽  
Long Distance ◽  
Genetic Substructure ◽  
Good Agreement

Spatial autocorrelation analysis was used to investigate the geographic distribution of allozyme genotypes within three natural populations of jack pine (Pinus banksiana Lamb.). Results indicate that genetic substructuring within these populations is very weak and the extent differs among populations. These results are in good agreement with those inferred from mating-system studies. Factors such as the species' predominantly outbreeding system, high mortality of selfs and inbreds prior to reproduction, long-distance pollen dispersal, and the absence of strong microhabitat selection may be responsible for the observed weak genetic substructuring. Key words: jack pine, Pinus banksiana, genetic substructure, allozyme, spatial autocorrelation analysis.

Establishment of local adaptation in partly self-fertilizing populations

Genetics ◽  
2021 ◽  
Author(s):  
Bogi Trickovic ◽  
Sylvain Glémin
Keyword(s):  
Local Adaptation ◽  
Pollen Dispersal ◽  
Theoretical Background ◽  
Weak Selection ◽  
Dominance Level ◽  
Self Fertilization ◽  
Protected Polymorphism ◽  
And Migration ◽  
Closed Form Approximation ◽  
Selfing Species

Abstract Populations often inhabit multiple ecological patches and thus experience divergent selection, which can lead to local adaptation if migration is not strong enough to swamp locally adapted alleles. Conditions for the establishment of a locally advantageous allele have been studied in randomly mating populations. However, many species reproduce, at least partially, through self-fertilization, and how selfing affects local adaptation remains unclear and debated. Using a two-patch branching process formalism, we obtained a closed-form approximation under weak selection for the probability of establishment of a locally advantageous allele (P) for arbitrary selfing rate and dominance level, where selection is allowed to act on viability or fecundity, and migration can occur via seed or pollen dispersal. This solution is compared to diffusion approximation and used to investigate the consequences of a shift in a mating system on P, and the establishment of protected polymorphism. We find that selfing can either increase or decrease P, depending on the patterns of dominance in the two patches, and has conflicting effects on local adaptation. Globally, selfing favors local adaptation when locally advantageous alleles are (partially) recessive, when selection between patches is asymmetrical and when migration occurs through pollen rather than seed dispersal. These results establish a rigorous theoretical background to study heterogeneous selection and local adaptation in partially selfing species.

Evidence of high self-fertilization in natural populations of eastern white cedar (Thuja occidentalis)

1990 ◽  
Vol 68 (3) ◽  
pp. 663-668 ◽  
Author(s):  
Daniel J. Perry ◽  
Peggy Knowles
Keyword(s):  
Natural Populations ◽  
Outcrossing Rate ◽  
Significant Heterogeneity ◽  
Embryo Survival ◽  
Thuja Occidentalis ◽  
White Cedar ◽  
Northwestern Ontario ◽  
Outcrossing Rates ◽  
Self Fertilization ◽  
Eastern White Cedar

Arrays of open-pollinated seeds were assayed for allozyme polymorphisms at four loci (Mdh-1, Me, 6Pg-2, and Pgm) to obtain estimates of outcrossing rates for three eastern white cedar populations in northwestern Ontario, Canada. Multilocus population outcrossing rate estimates were low, ranging from 0.507 to 0.745, with significant heterogeneity among populations. Low stand densities and relatively high selfed embryo survival may have contributed to the low effective outcrossing rates observed. Single-tree multilocus outcrossing rate estimates were obtained for nine trees from one population. When estimated jointly with outcross pollen pool allele frequencies, these outcrossing rate estimates ranged from 0.253 to 1.023 with significant heterogeneity among trees. Key words: mating system, outcrossing rate, Thuja occidentalis L.

Low levels of outcrossing in Pinus leucodermis: further evidence in artificial stands

1994 ◽  
Vol 72 (9) ◽  
pp. 1289-1293 ◽  
Author(s):  
M. Morgante ◽  
P. Rossi ◽  
G. G. Vendramin ◽  
G. Boscherini
Keyword(s):  
Natural Populations ◽  
Selective Advantage ◽  
Minimum Variance ◽  
Outcrossing Rates ◽  
Self Fertilization ◽  
Low Levels ◽  
High Level ◽  
Germinating Seeds ◽  
Neighbourhood Structure ◽  
Key Words Mating System

Outcrossing rates were estimated in two artificial stands of Pinus leucodermis, a wind pollinated conifer characterized by a relatively high level of selfing. Multilocus outcrossing rates, estimated by assaying five enzyme loci, were lower than 86% in the two stands, using both dormant and germinating seeds, and not different from those observed in two natural populations located in the same area. The lack of relevant differences between single-locus minimum variance means and the multilocus outcrossing rate estimates observed in both the artificial stands indicates that most of the apparent selfing is probably caused by actual self-fertilization. The presence of a high level of self-fertilization in this species seems confirmed also in artificial stands, where the density is higher and neighbourhood structure should be less pronounced. The high level of self-fertilization found in P. leucodermis, which is probably due to the presence of a reduced number of recessive embryonic lethals as a consequence of genetic drift, could represent a selective advantage for this pioneering and precocius species. Key words: mating system, outcrossing rates, artificial stands, Pinus leucodermis.

Distinguishing error from chaos in ecological time series

1990 ◽  
Vol 330 (1257) ◽  
pp. 235-251 ◽  
Keyword(s):  
New York ◽  
Population Density ◽  
Sampling Error ◽  
Natural Populations ◽  
Real Data ◽  
Environmental Stochasticity ◽  
Population Variation ◽  
Data Sets ◽  
Spatial Effects ◽  
Low Dimensional

Over the years, there has been much discussion about the relative importance of environmental and biological factors in regulating natural populations. Often it is thought that environmental factors are associated with stochastic fluctuations in population density, and biological ones with deterministic regulation. We revisit these ideas in the light of recent work on chaos and nonlinear systems. We show that completely deterministic regulatory factors can lead to apparently random fluctuations in population density, and we then develop a new method (that can be applied to limited data sets) to make practical distinctions between apparently noisy dynamics produced by low-dimensional chaos and population variation that in fact derives from random (high-dimensional)noise, such as environmental stochasticity or sampling error. To show its practical use, the method is first applied to models where the dynamics are known. We then apply the method to several sets of real data, including newly analysed data on the incidence of measles in the United Kingdom. Here the additional problems of secular trends and spatial effects are explored. In particular, we find that on a city-by-city scale measles exhibits low-dimensional chaos (as has previously been found for measles in New York City), whereas on a larger, country-wide scale the dynamics appear as a noisy two-year cycle. In addition to shedding light on the basic dynamics of some nonlinear biological systems, this work dramatizes how the scale on which data is collected and analysed can affect the conclusions drawn.

Adaptive Hierarchical Bayes Estimation of Small Area Proportions

2017 ◽  
Vol 69 (2) ◽  
pp. 150-164 ◽  
Author(s):  
Benmei Liu ◽  
Partha Lahiri
Keyword(s):  
Random Effects ◽  
Small Area ◽  
Probability Distributions ◽  
Random Effect ◽  
Real Data ◽  
Hierarchical Bayes ◽  
Bayes Estimation ◽  
Proposed Model ◽  
Exponential Power ◽  
Power Class

Unit-level logistic regression models with mixed effects have been used for estimating small area proportions in the literature. Normality is commonly assumed for the random effects. Nonetheless, real data often show significant departures from normality assumptions of the random effects. To reduce the risk of model misspecification, we propose an adaptive hierarchical Bayes estimation approach in which the distribution of the random effect is chosen adaptively from the exponential power class of probability distributions. The richness of the exponential power class ensures the robustness of our hierarchical Bayes approach against departure from normality. We demonstrate the robustness of our proposed model using both simulated and real data. The results suggest that the proposed model works reasonably well to incorporate potential kurtosis of the random effects distribution.

Extensive seed and pollen dispersal and assortative mating in the rain forest tree Entandrophragma cylindricum (Meliaceae) inferred from indirect and direct analyses

2017 ◽  
Vol 26 (19) ◽  
pp. 5279-5291 ◽  
Author(s):  
Franck Kameni Monthe ◽  
Olivier J. Hardy ◽  
Jean-Louis Doucet ◽  
Judy Loo ◽  
Jérôme Duminil
Keyword(s):  
Assortative Mating ◽  
Rain Forest ◽  
Pollen Dispersal ◽  
Forest Tree

scholarly journals The Location-Scale Mixture Exponential Power Distribution: A Bayesian and Maximum Likelihood Approach

2012 ◽  
Vol 2012 ◽  
pp. 1-14
Author(s):  
Z. Rahnamaei ◽  
N. Nematollahi ◽  
R. Farnoosh
Keyword(s):  
Maximum Likelihood ◽  
Power Distribution ◽  
Real Data ◽  
Scale Mixture ◽  
Exponential Power Distribution ◽  
Likelihood Approach ◽  
Slash Distribution ◽  
Exponential Power ◽  
Mean Square Errors ◽  
New Distribution

We introduce an alternative skew-slash distribution by using the scale mixture of the exponential power distribution. We derive the properties of this distribution and estimate its parameter by Maximum Likelihood and Bayesian methods. By a simulation study we compute the mentioned estimators and their mean square errors, and we provide an example on real data to demonstrate the modeling strength of the new distribution.

scholarly journals On Generalized Moment Exponential Distribution and Power Series Distribution

2020 ◽  
pp. 1-21
Author(s):  
Zafar Iqbal ◽  
Noreen Ali ◽  
Abdur Razaq ◽  
Tassaddaq Hussain ◽  
Muhammad Salman
Keyword(s):  
Power Series ◽  
Estimation Method ◽  
Life Time ◽  
Real Data ◽  
Quantile Function ◽  
Lambert W Function ◽  
Ml Estimation ◽  
Exponential Power ◽  
Generalized Moment ◽  
Family Of Distributions

In this research paper, a new life time family is introduced. Sadaf [1] proposed a moment exponential power series (MEPS) distribution. Generalized moment exponential power series (GMEPS) distribution is a general form of MEPS distribution. It is characterized by compounding GME distribution and power series (PS) distribution. This new family has some new sub models such as GME geometric distribution, GME Poisson (GMEP) distribution, GME logarithmic (GMEL) distribution and GME binomial (GMEB) distribution. We provide statistical properties of GMEPS family of distributions. We find here expression of quantile function based on Lambert W function, the density function of rth order statistic and moments of GMEPS distribution. Descriptive expressions of Shannon entropy and Rényi entropy of new general model are found. We provide special sub-models of the GMEPS family of distributions. The maximum likelihood (ML) estimation method is used to find estimates of the parameters of GMEPS distribution. Simulation study is carried out to check the convergence of new estimators. We apply GMEPS family of distributions on two sets of real data.

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