Modeling large-scale dispersal distances

Knowledge of pollen movement and frequency of interspecific hybridization in fragmented populations of rare species is a prerequisite for the implementation of conservation measures. In a large-scale study area (14,000 hectares) we analysed 297 Malus sylvestris trees with nine nuclear microsatellite markers. After open pollination of 564 offspring from 51 mother trees located in seven harvesting sites were investigated and genetic paternity analysis was performed. The paternal parent was identified for 213 offspring and the pollen dispersal distances between mother and pollen source were calculated. A large proportion of detected pollination events (42.4%) were observed within a radius of 50 m of the mother tree. The comparison of different tree densities indicated that with decreasing density the pollen dispersal distances increase. We observed pollination over long distances with a maximum of 10.7 km which is probably one of the reasons for a low spatial genetic structure within the M. sylvestris population and a stable genetic diversity in the offspring. Incorporating microsatellite data of 21 apple cultivars, a hybridization frequency of nearly 8% was determined. With decreasing tree density the number of hybridization events increased. Based on the results of our study an enhancement of the density of existing M. sylvestris populations is recommend to reduce the likelihood of hybridization. The production of young plants originated from seeds collected after open pollination is not advisable. Instead of that the seedlings for further reintroduction measures should be produced by controlled crossings in seed orchards to ensure ‘true type’ M. sylvestris individuals.

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Population connectivity across a transboundary conservation network: potential for restoration?

10.21203/rs.3.rs-452520/v1 ◽

2021 ◽

Author(s):

Simon Dures ◽

Chris Carbone ◽

Andrew J Loveridge ◽

Glyn Maude ◽

Neil Midland ◽

...

Keyword(s):

Population Structure ◽

Gene Flow ◽

Functional Connectivity ◽

Large Scale ◽

Population Connectivity ◽

Sub Saharan Africa ◽

Likelihood Method ◽

Mobile Species ◽

Transboundary Conservation ◽

Dispersal Distances

Abstract Context: There has been limited research identifying large-scale functional connectivity of wildlife populations across sub-Saharan Africa, despite the increased focus on transboundary conservation networks. Objectives: This study set out to assess the functional connectivity of a highly mobile predator of conservation concern across the Kavango-Zambezi transboundary conservation area (KAZA) and the northern Central Kalahari Game Reserve (CKGR), covering almost 300,000km2 of Botswana, Namibia, Zambia and Zimbabwe.Methods: We analysed the nuclear diversity of 204 individual lions from across the metapopulation using Bayesian and multivariate statistics to assess population structure and recent migration. A maximum-likelihood method was used to determine average male dispersal distances to determine the potential for functional connectivity across the region.Results: The results are consistent with work identifying the existence of ecotypic differences between wetland and dryland lions, but also indicate hierarchical population structure further dividing the population into four geographic clusters; the Okavango Delta, the Central Kalahari, Kafue National Park, and the Hwange-Chobe complex. Analysis of dispersal distances of males suggests that reconnecting the clusters through conservation intervention should be successful in improving gene flow and connectivity across the region. Conclusions: While trans-boundary conservation areas may currently have limited gene flow and connectivity, there is potential for the restoration of functional connectivity via the natural dispersal of highly mobile species. However, the matrix of habitat through which such dispersing animals must traverse must be conducive to their movement and survival, highlighting the importance of land outside protected areas for the preservation of highly mobile animals such as lions.

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The allometry of movement predicts the connectivity of communities

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2001614117 ◽

2020 ◽

Vol 117 (36) ◽

pp. 22274-22280 ◽

Cited By ~ 1

Author(s):

Jack Hartfelder ◽

Chevonne Reynolds ◽

Richard A. Stanton ◽

Muzi Sibiya ◽

Ara Monadjem ◽

...

Keyword(s):

Large Scale ◽

Allometric Scaling ◽

Animal Movement ◽

Community Level ◽

Conservation Strategies ◽

Bird Diversity ◽

Individual Species ◽

Translocation Experiment ◽

Community Theory ◽

Dispersal Distances

Connectivity has long played a central role in ecological and evolutionary theory and is increasingly emphasized for conserving biodiversity. Nonetheless, connectivity assessments often focus on individual species even though understanding and preserving connectivity for entire communities is urgently needed. Here we derive and test a framework that harnesses the well-known allometric scaling of animal movement to predict community-level connectivity across protected area networks. We used a field translocation experiment involving 39 species of southern African birds to quantify movement capacity, scaled this relationship to realized dispersal distances determined from ring-and-recovery banding data, and used allometric scaling equations to quantify community-level connectivity based on multilayer network theory. The translocation experiment explained observed dispersal distances from ring-recovery data and emphasized allometric scaling of dispersal based on morphology. Our community-level networks predicted that larger-bodied species had a relatively high potential for connectivity, while small-bodied species had lower connectivity. These community networks explained substantial variation in observed bird diversity across protected areas. Our results highlight that harnessing allometric scaling can be an effective way of determining large-scale community connectivity. We argue that this trait-based framework founded on allometric scaling provides a means to predict connectivity for entire communities, which can foster empirical tests of community theory and contribute to biodiversity conservation strategies aimed at mitigating the effects of environmental change.

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Sex-biased dispersal in a northern ungulate population

Rangifer ◽

10.7557/2.31.1.2038 ◽

2011 ◽

Vol 31 (1) ◽

pp. 139 ◽

Cited By ~ 4

Author(s):

Hallvard Haanes ◽

Knut H. Røed ◽

Olav Rosef

Keyword(s):

Genetic Structure ◽

Cervus Elaphus ◽

Large Scale ◽

First Generation ◽

Red Deer ◽

Small Scale ◽

Bayesian Analyses ◽

Allele Distribution ◽

Population Information ◽

Dispersal Distances

In most mammals dispersal is male-biased and in many polygynous ungulates female philopatry and matrilineal grouping involve small-scale genetic structure. We have through sex-related differences in microsatellite allele distribution addressed sex-biased dispersal in a spatially expanding northern ungulate population. The Norwegian red deer population (Cervus elaphus atlanticus) has the last hundred years grown substantially and expanded spatially after a major decline from 300 to 100 years ago. Previous Bayesian analyses suggest a present division of genetic variation into five geographically separated subpopulations. Among these subpopulations the overall Fst values were 0.067 (SE=0.014) for males and 0.094 (SE=0.017) for females. Pairwise Fst values were significantly higher for females than males, demonstrating a stronger genetic structure among females, and that dispersal has been lower in females than males. Accordingly, a higher number of male than female first generation dispersers were identified among the five subpopulations using Bayesian assignment with prior population information, but significantly so only with relaxed stringency levels of assignment. The identified male-biased dispersal distances varied from 30 to 300 kilometers suggesting male biased dispersal on a large scale in red deer.

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Some comments about observations and image processing of comet 29P/Schwassmann-Wachmann 1

International Astronomical Union Colloquium ◽

10.1017/s0252921100031493 ◽

1999 ◽

Vol 173 ◽

pp. 243-248

Author(s):

D. Kubáček ◽

A. Galád ◽

A. Pravda

Keyword(s):

Image Processing ◽

Large Scale ◽

Harvard College ◽

Oak Ridge ◽

Large Scale Structures ◽

Short Period Comet ◽

Short Period ◽

Scale Structures ◽

Harvard College Observatory ◽

Period Comet

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.

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Evolution of Large-Scale Coronal Structures

International Astronomical Union Colloquium ◽

10.1017/s0252921100024945 ◽

1994 ◽

Vol 144 ◽

pp. 29-33

Author(s):

P. Ambrož

Keyword(s):

Magnetic Field ◽

Field Line ◽

Large Scale ◽

Coronal Magnetic Field ◽

Source Surface ◽

Solar Cycles ◽

Characteristic Relationship ◽

The Magnetic Field ◽

Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

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Large-scale Motion of Solar Filaments

International Astronomical Union Colloquium ◽

10.1017/s0252921100064502 ◽

2000 ◽

Vol 179 ◽

pp. 205-208

Author(s):

Pavel Ambrož ◽

Alfred Schroll

Keyword(s):

Magnetic Flux ◽

Proper Motion ◽

Time Scale ◽

Large Scale ◽

Accuracy Of Measurements ◽

Solar Filaments ◽

General Movement ◽

Scale Motion ◽

Velocity Scatter

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

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Some applications of electron beam microanalysis techniques in VLSI process evaluation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010007463x ◽

1983 ◽

Vol 41 ◽

pp. 160-161

Author(s):

Simon Thomas

Keyword(s):

Integrated Circuits ◽

Process Evaluation ◽

Large Scale ◽

Technology Development ◽

Analytical Techniques ◽

Successful Implementation ◽

Analysis Of Failures ◽

Characterization Of Materials ◽

Circuits Vlsi

Trends in the technology development of very large scale integrated circuits (VLSI) have been in the direction of higher density of components with smaller dimensions. The scaling down of device dimensions has been not only laterally but also in depth. Such efforts in miniaturization bring with them new developments in materials and processing. Successful implementation of these efforts is, to a large extent, dependent on the proper understanding of the material properties, process technologies and reliability issues, through adequate analytical studies. The analytical instrumentation technology has, fortunately, kept pace with the basic requirements of devices with lateral dimensions in the micron/ submicron range and depths of the order of nonometers. Often, newer analytical techniques have emerged or the more conventional techniques have been adapted to meet the more stringent requirements. As such, a variety of analytical techniques are available today to aid an analyst in the efforts of VLSI process evaluation. Generally such analytical efforts are divided into the characterization of materials, evaluation of processing steps and the analysis of failures.

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Electron microscopy study of reactively sputter-deposited Ti/N films on silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100131449 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1362-1363

Author(s):

V. C. Kannan ◽

A. K. Singh ◽

R. B. Irwin ◽

S. Chittipeddi ◽

F. D. Nkansah ◽

...

Keyword(s):

Integrated Circuits ◽

Large Scale ◽

Hexagonal Phase ◽

Microscopy Study ◽

Electron Microscopy Study ◽

Process Conditions ◽

Tin Films ◽

Wide Range ◽

Fcc Phase ◽

Circuits Vlsi

Titanium nitride (TiN) films have historically been used as diffusion barrier between silicon and aluminum, as an adhesion layer for tungsten deposition and as an interconnect material etc. Recently, the role of TiN films as contact barriers in very large scale silicon integrated circuits (VLSI) has been extensively studied. TiN films have resistivities on the order of 20μ Ω-cm which is much lower than that of titanium (nearly 66μ Ω-cm). Deposited TiN films show resistivities which vary from 20 to 100μ Ω-cm depending upon the type of deposition and process conditions. TiNx is known to have a NaCl type crystal structure for a wide range of compositions. Change in color from metallic luster to gold reflects the stabilization of the TiNx (FCC) phase over the close packed Ti(N) hexagonal phase. It was found that TiN (1:1) ideal composition with the FCC (NaCl-type) structure gives the best electrical property.

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Evolution of the microstructure of Cu(Ti)/SiO2 layers annealed in NH3

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100138634 ◽

1995 ◽

Vol 53 ◽

pp. 452-453

Author(s):

J. Liu ◽

N. D. Theodore ◽

D. Adams ◽

S. Russell ◽

T. L. Alford ◽

...

Keyword(s):

Thermal Stability ◽

Titanium Nitride ◽

Large Scale ◽

Standard Procedure ◽

Alloy Film ◽

Electron Beam Evaporation ◽

Copper Metallization ◽

Nominal Composition ◽

Ti Alloy ◽

Thermally Grown

Copper-based metallization has recently attracted extensive research because of its potential application in ultra-large-scale integration (ULSI) of semiconductor devices. The feasibility of copper metallization is, however, limited due to its thermal stability issues. In order to utilize copper in metallization systems diffusion barriers such as titanium nitride and other refractory materials, have been employed to enhance the thermal stability of copper. Titanium nitride layers can be formed by annealing Cu(Ti) alloy film evaporated on thermally grown SiO2 substrates in an ammonia ambient. We report here the microstructural evolution of Cu(Ti)/SiO2 layers during annealing in NH3 flowing ambient.The Cu(Ti) films used in this experiment were prepared by electron beam evaporation onto thermally grown SiO2 substrates. The nominal composition of the Cu(Ti) alloy was Cu73Ti27. Thermal treatments were conducted in NH3 flowing ambient for 30 minutes at temperatures ranging from 450°C to 650°C. Cross-section TEM specimens were prepared by the standard procedure.

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