What limits the distribution and abundance of the native conifer Callitris glaucophylla (Cupressaceae) in the West MacDonnell Ranges, central Australia?

2010 ◽  
Vol 58 (7) ◽  
pp. 554 ◽  
Author(s):  
Lynda D. Prior ◽  
Zoe Lee ◽  
Chris Brock ◽  
Grant J. Williamson ◽  
David M. J. S. Bowman
Keyword(s):  
Population Structure ◽  
Fire History ◽  
Size Class ◽  
The West ◽  
Adult Trees ◽  
Australian Continent ◽  
Population Structures ◽  
Callitris Glaucophylla ◽  
Central Australia ◽  
Negative Exponential

The conifer Callitris glaucophylla J.Thompson & L.A.S.Johnson (Cupressaceae) is a fire-sensitive obligate seeder with a heavily fragmented distribution across the Australian continent. We undertook a broad-scale biophysical survey and analysed the population structure of 21 populations in the West MacDonnell Ranges of central Australia. C. glaucophylla had a patchy distribution associated with steep, rocky metamorphic areas with limited evidence of fire. Variation in population structures was clearly related to recent fire history. Nearly half of ‘adult’ C. glaucophylla trees (>5-cm stem diameter) from the sampled stands were dead, with the proportion at individual sites related to evidence of fire. Fire scars were evident on 48% of all live trees we measured. The overall density of live adult trees conformed to a negative exponential size-class distribution, consistent with a regionally stable population structure. However, we found higher sapling densities and lower seedlings densities than expected by this distribution. This regional peak in the sapling size class reflects a pulse of recruitment, possibly associated with a wet period in the 1970s. Low seedling densities are probably due to subsequent drought. We conclude that fire controls the distribution of Callitris on the West MacDonnell Ranges, and the timing of recruitment depends on rainfall patterns.

Scientific exploration of Central Australia

1868 ◽  
Vol 16 ◽  
pp. 347-364
Keyword(s):  
Sandy Desert ◽  
The West ◽  
North West ◽  
Inland Lakes ◽  
The North ◽  
Scientific Exploration ◽  
Australian Continent ◽  
Central Australia ◽  
Better Than ◽  
Vast Territory

If we look on a map of the Australian continent published ten years ago, we are struck by the immense expause of land then unexplored; we perceive at a glance that the south-eastern sea-board only of this great continent had then been examined with any degree ot accuracy, and that very little was known to us respecting the character of its shores on the west and north-west. In two quarters only had the zeal and daring of tire explorer succeeded in forcing a path towards the central portions of this vast territory, Sturt having penetrated as far as 24° South and 138° East, and Gregory as far as 21° South and 128° East. The nature of the country traversed by these two eminent explorers was such as to countenance the supposition, that the interior of Australia was little better than one vast desert, offering almost insurmountable obstacles to exploration. The idea, originally advanced by Oxley, that the greater part of the interim was occupied by vast inland lakes, was then abandoned; and the theory just mentioned took its place. In such a state of utter uncertainty as to the nature of the interior of a vast continent, it is but natural that various theories should be started; and no doubt they will, in the end, help to keep up the spirit for rigorous examination and exploration, yet care must be taken that they do not, by the unfavourable nature of their suppositions, tend to discourage enterprise. From such a danger we had a narrow escape during the years following A. C. Gregory’s exploration of the interior, and his expedition in search of Dr. Leichhardt, as at that time it was generally believed that the arid plains and stony deserts met with in the east and south, and the sandy desert in the north-west, were but the outskirts of a desert country unparalleled on our globe.

Surnames and population structure in the Doctrine of Belén, Altos de Arica, Viceroyalty of Peru (1750–1813)

2021 ◽  
pp. 1-13
Author(s):  
Emma Alfaro ◽  
Xochitl Inostroza ◽  
José E. Dipierri ◽  
Daniela Peña Aguilera ◽  
Jorge Hidalgo ◽  
...  
Keyword(s):  
Population Structure ◽  
Indigenous Population ◽  
Random Mating ◽  
Quantitative Information ◽  
Geographic Space ◽  
Documentary Sources ◽  
Cultural Variables ◽  
The Social ◽  
Population Structures ◽  
And Migration

Abstract The analysis of multiple population structures (biodemographic, genetic and socio-cultural) and their inter-relations contribute to a deeper understanding of population structure and population dynamics. Genetically, the population structure corresponds to the deviation of random mating conditioned by a limited number of ancestors, by restricted migration in the social or geographic space, or by preference for certain consanguineous unions. Through the isonymic method, surname frequency and distribution across the population can supply quantitative information on the structure of a human population, as they constitute universal socio-cultural variables. Using documentary sources to undertake the Doctrine of Belén’s (Altos de Arica, Chile) historical demography reconstruction between 1763 and 1820, this study identified an indigenous population with stable patronymics. The availability of complete marriage, baptism and death records, low rates of migration and the significant percentage of individuals registered and constantly present in this population favoured the application of the isonymic method. The aim of this work was to use given names and surnames recorded in these documentary sources to reconstruct the population structure and migration pattern of the Doctrine of Belén between 1750 and 1813 through the isonymic method. The results of the study were consistent with the ethno-historical data of this ethnic space, where social cohesion was, in multiple ways, related to the regulation of daily life in colonial Andean societies.

scholarly journals Non-Homogeneous Markov Set Systems

Mathematics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 471
Author(s):  
P.-C.G. Vassiliou
Keyword(s):  
Asymptotic Behavior ◽  
Population Structure ◽  
Confidence Intervals ◽  
Limit Set ◽  
Stroke Patients ◽  
Relative Population ◽  
Set Systems ◽  
Population Structures ◽  
Basic Parameters ◽  
Initial Distributions

A more realistic way to describe a model is the use of intervals which contain the required values of the parameters. In practice we estimate the parameters from a set of data and it is natural that they will be in confidence intervals. In the present study, we study Non-Homogeneous Markov Systems (NHMS) processes for which the required basic parameters are in intervals. We call such processes Non-Homogeneous Markov Set Systems (NHMSS). First we study the set of the relative expected population structure of memberships and we prove that under certain conditions of convexity of the intervals of the parameters the set is compact and convex. Next, we establish that if the NHMSS starts with two different initial distributions sets and allocation probability sets under certain conditions, asymptotically the two expected relative population structures coincide geometrically fast. We continue proving a series of theorems on the asymptotic behavior of the expected relative population structure of a NHMSS and the properties of their limit set. Finally, we present an application for geriatric and stroke patients in a hospital and through it we solve problems that surface in an application.

scholarly journals Detecting a hierarchical genetic population structure via Multi-InDel markers on the X chromosome

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Guang Yao Fan ◽  
Yi Ye ◽  
Yi Ping Hou
Keyword(s):  
Population Structure ◽  
X Chromosome ◽  
Cost Effective ◽  
Genetic Distances ◽  
Ancestry Informative Marker ◽  
Genetic Population ◽  
Single Nucleotide ◽  
Chinese Populations ◽  
Population Structures ◽  
Biogeographical Ancestry

Abstract Detecting population structure and estimating individual biogeographical ancestry are very important in population genetics studies, biomedical research and forensics. Single-nucleotide polymorphism (SNP) has long been considered to be a primary ancestry-informative marker (AIM), but it is constrained by complex and time-consuming genotyping protocols. Following up on our previous study, we propose that a multi-insertion-deletion polymorphism (Multi-InDel) with multiple haplotypes can be useful in ancestry inference and hierarchical genetic population structures. A validation study for the X chromosome Multi-InDel marker (X-Multi-InDel) as a novel AIM was conducted. Genetic polymorphisms and genetic distances among three Chinese populations and 14 worldwide populations obtained from the 1000 Genomes database were analyzed. A Bayesian clustering method (STRUCTURE) was used to discern the continental origins of Europe, East Asia, and Africa. A minimal panel of ten X-Multi-InDels was verified to be sufficient to distinguish human ancestries from three major continental regions with nearly the same efficiency of the earlier panel with 21 insertion-deletion AIMs. Along with the development of more X-Multi-InDels, an approach using this novel marker has the potential for broad applicability as a cost-effective tool toward more accurate determinations of individual biogeographical ancestry and population stratification.

scholarly journals Evolution and Population Structure of Salmonella enterica Serovar Newport

2010 ◽  
Vol 192 (24) ◽  
pp. 6465-6476 ◽  
Author(s):  
Vartul Sangal ◽  
Heather Harbottle ◽  
Camila J. Mazzoni ◽  
Reiner Helmuth ◽  
Beatriz Guerra ◽  
...  
Keyword(s):  
Population Structure ◽  
North America ◽  
Salmonella Enterica ◽  
Health Concern ◽  
Global Public Health ◽  
Multiple Sequence ◽  
Monophyletic Lineage ◽  
Population Structures ◽  
Paratyphi B ◽  
Multiple Drugs

ABSTRACT Salmonellosis caused by Salmonella enterica serovar Newport is a major global public health concern, particularly because S. Newport isolates that are resistant to multiple drugs (MDR), including third-generation cephalosporins (MDR-AmpC phenotype), have been commonly isolated from food animals. We analyzed 384 S. Newport isolates from various sources by a multilocus sequence typing (MLST) scheme to study the evolution and population structure of the serovar. These were compared to the population structure of S. enterica serovars Enteritidis, Kentucky, Paratyphi B, and Typhimurium. Our S. Newport collection fell into three lineages, Newport-I, Newport-II, and Newport-III, each of which contained multiple sequence types (STs). Newport-I has only a few STs, unlike Newport-II or Newport-III, and has possibly emerged recently. Newport-I is more prevalent among humans in Europe than in North America, whereas Newport-II is preferentially associated with animals. Two STs of Newport-II encompassed all MDR-AmpC isolates, suggesting recent global spread after the acquisition of the bla CMY-2 gene. In contrast, most Newport-III isolates were from humans in North America and were pansusceptible to antibiotics. Newport was intermediate in population structure to the other serovars, which varied from a single monophyletic lineage in S. Enteritidis or S. Typhimurium to four discrete lineages within S. Paratyphi B. Both mutation and homologous recombination are responsible for diversification within each of these lineages, but the relative frequencies differed with the lineage. We conclude that serovars of S. enterica provide a variety of different population structures.

scholarly journals Effect of unfavourable population structure on estimates of heritability, systematic effects and breeding values

2008 ◽  
Vol 51 (6) ◽  
pp. 601-610
Author(s):  
A. P. Kominakis
Keyword(s):  
Population Structure ◽  
Mean Squared Error ◽  
Heritability Estimate ◽  
Breeding Values ◽  
Parameter Estimations ◽  
Squared Error ◽  
Heritability Estimation ◽  
Population Structures ◽  
Systematic Effects ◽  
The Impact

Abstract. Empirical estimations of heritability, systematic effects and predictions of sires’ breeding values (BVs) were obtained under various population structures for simulated populations consisted of n = 400 animals in 5 herds for a trait of medium heritability (h2 = 0.30). An infinitesimal additive genetic animal model was assumed while simulating data. Population structure was varied to allow for good and poor connectedness across herds and (non)random association between the genetic and the environmental effects. The impact of the various population structures on the parameter estimation(s) was assessed using Mean Squared Error (MSE) and Pearson’s correlations. Allowing sires to have progenies in more than one herd (good herd connectedness) and random use of sires across herds generally resulted in good parameter estimations. Poor connectedness significantly affected herd effects estimation and BV prediction but not heritability estimation as long as random usage of sires across environments was guaranteed. Selective use of the best sires in the best herds along with poor connectedness resulted in poorest estimations of all parameters examined. In the latter case, heritability was seriously underestimated (h2 = 0.06) while highest error, lowest accuracies for the BVs and a remarkable underestimation of the genetic gain were observed. Use of reference sires on a natural mating basis to create genetic links between herds has served a good solution for both heritability and BVs estimation under unfavorable structure. Mating 0.25 of the herd ewes with reference sires resulted in a heritability estimate close to the simulated one. Significantly better estimates of systematic effects and BVs were, however, obtained when 0.5 of the herd ewes were mated by reference sires.

scholarly journals Ordering structured populations in multiplayer cooperation games

2015 ◽  
Author(s):  
Jorge Peña ◽  
Bin Wu ◽  
Arne Traulsen
Keyword(s):  
Population Structure ◽  
Spatial Structure ◽  
Structured Populations ◽  
Evolution Of Cooperation ◽  
Multiplayer Games ◽  
Spatial Games ◽  
Population Structures ◽  
Single Structure ◽  
Containment Order ◽  
Update Rules

AbstractSpatial structure greatly affects the evolution of cooperation. While in two-player games the condition for cooperation to evolve depends on a single structure coefficient, in multiplayer games the condition might depend on several structure coefficients, making it difficult to compare different population structures. We propose a solution to this issue by introducing two simple ways of ordering population structures: the containment order and the volume order. If population structure 𝒮1 is greater than population structure 𝒮2 in the containment or the volume order, then 𝒮1 can be considered a stronger promoter of cooperation. We provide conditions for establishing the containment order, give general results on the volume order, and illustrate our theory by comparing different models of spatial games and associated update rules. Our results hold for a large class of population structures and can be easily applied to specific cases once the structure coefficients have been calculated or estimated.

scholarly journals Genetic Diversity in the mtDNA control region and population structure of Chrysichthys nigrodigitatus from selected Nigerian rivers: Implications for conservation and aquaculture

2016 ◽  
Vol 24 (2) ◽  
pp. 85-97 ◽  
Author(s):  
Sylvanus A. Nwafili ◽  
Tian-Xiang Gao
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Control Region ◽  
Haplotype Diversity ◽  
Population Expansion ◽  
Mitochondrial Control Region ◽  
Recent Population Expansion ◽  
Base Pair Fragment ◽  
Population Structures ◽  
High Level

Abstract The genetic diversity and population structure of Chrysichthys nigrodigitatus were evaluated using a 443 base pair fragment of the mitochondrial control region. Among the eight populations collected comprising 129 individuals, a total of 89 polymorphic sites defined 57 distinct haplotypes. The mean haplotype diversity and nucleotide diversity of the eight populations were 0.966±0.006 and 0.0359±0.004, respectively. Analysis of molecular variance showed significant genetic differentiation among the eight populations (FST =0.34; P < 0.01). The present results revealed that C. nigrodigitatus populations had a high level of genetic diversity and distinct population structures. We report the existence of two monophyletic matrilineal lineages with mean genetic distance of 10.5% between them. Non-significant negative Tajima’s D and Fu’s Fs for more than half the populations suggests that the wild populations of C. nigrodigitatus underwent a recent population expansion, although a weak one since the late Pleistocene.

scholarly journals Coevolutionary fine-tuning: evidence for genetic tracking between a specialist wasp parasitoid and its aphid host in a dual metapopulation interaction

2011 ◽  
Vol 102 (2) ◽  
pp. 149-155 ◽  
Author(s):  
F.N. Nyabuga ◽  
H.D. Loxdale ◽  
D.G. Heckel ◽  
W.W. Weisser
Keyword(s):  
Population Structure ◽  
Life Histories ◽  
Mantel Test ◽  
Fine Tuning ◽  
Red Queen Hypothesis ◽  
Shared Allele ◽  
Metapopulation Structure ◽  
Population Structures ◽  
Associated Species ◽  
Aphid Host

AbstractIn the interaction between two ecologically-associated species, the population structure of one species may affect the population structure of the other. Here, we examine the population structures of the aphidMetopeurum fuscoviride, a specialist on tansyTanacetum vulgare, and its specialist primary hymenopterous parasitoidLysiphlebus hirticornis, both of which are characterized by multivoltine life histories and a classic metapopulation structure. Samples of the aphid host and the parasitoid were collected from eight sites in and around Jena, Germany, where both insect species co-occur, and then were genotyped using suites of polymorphic microsatellite markers. The host aphid was greatly differentiated in terms of its spatial population genetic patterning, while the parasitoid was, in comparison, only moderately differentiated. There was a positive Mantel test correlation between pairwise shared allele distance (DAS) of the host and parasitoid, i.e. if host subpopulation samples were more similar between two particular sites, so were the parasitoid subpopulation samples. We argue that while the differences in the levels of genetic differentiation are due to the differences in the biology of the species, the correlations between host and parasitoid are indicative of dependence of the parasitoid population structure on that of its aphid host. The parasitoid is genetically tracking behind the aphid host, as can be expected in a classic metapopulation structure where host persistence depends on a delay between host and parasitoid colonization of the patch. The results may also have relevance to the Red Queen hypothesis, whereupon in the ‘arms race’ between parasitoid and its host, the latter ‘attempts’ to evolve away from the former.

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