Temporal and spatial mating-system variation in fragmented populations of Banksia cuneata, a rare bird-pollinated long-lived plant

2013 ◽  
Vol 61 (4) ◽  
pp. 235 ◽  
Author(s):  
David J. Coates ◽  
Matthew R. Williams ◽  
Sally Madden
Keyword(s):  
Temporal Variation ◽  
Mating System ◽  
Fixation Index ◽  
Fragmented Landscape ◽  
Plant Populations ◽  
Spatial Uniformity ◽  
Outcrossing Rates ◽  
Plant Mating Systems ◽  
Temporal And Spatial ◽  
The Difference

Plant mating systems can vary significantly in both space and time, influencing a range of demographic and genetic processes critical for the persistence of plant populations. Spatial and temporal mating-system variations were investigated in Banksia cuneata (A. S. George), a rare bird-pollinated shrub occurring in a highly fragmented landscape. Substantial variation in the mating system was observed, with the magnitude of temporal variation within a population often as high as the level of spatial variation among populations within a season. A significant reduction in outcrossing rates and increased temporal variation in both outcrossing rates and correlated paternity were observed in disturbed populations. Doubling of the paternal neighbourhood and a trend to increased outcrossing rate was found after augmentation of a disturbed population where population size was increased from 57 to 214 adult plants. A large increase in the fixation index for seeds compared with adults was observed in all populations, with the magnitude of the difference showing temporal and spatial uniformity. We suggest that temporal mating-system variation warrants increased consideration, not only in assessing the effects of habitat fragmentation on plant populations, but also in the design and establishment of successful translocation, augmentation and restoration programs.

Inferring Recent Outcrossing Rates Using Multilocus Individual Heterozygosity: Application to Evolving Wheat Populations

Genetics ◽  
2000 ◽  
Vol 156 (4) ◽  
pp. 1973-1982
Author(s):  
Jérôme Enjalbert ◽  
Jacques L David
Keyword(s):  
Maximum Likelihood ◽  
Temporal Variation ◽  
Mating System ◽  
Outcrossing Rate ◽  
Outcrossing Rates ◽  
Progeny Analysis ◽  
Ml Estimator ◽  
Two Populations

Abstract Using multilocus individual heterozygosity, a method is developed to estimate the outcrossing rates of a population over a few previous generations. Considering that individuals originate either from outcrossing or from n successive selfing generations from an outbred ancestor, a maximum-likelihood (ML) estimator is described that gives estimates of past outcrossing rates in terms of proportions of individuals with different n values. Heterozygosities at several unlinked codominant loci are used to assign n values to each individual. This method also allows a test of whether populations are in inbreeding equilibrium. The estimator’s reliability was checked using simulations for different mating histories. We show that this ML estimator can provide estimates of outcrossing rates for the final generation outcrossing rate (t0) and a mean of the preceding rates (tp) and can detect major temporal variation in the mating system. The method is most efficient for low to intermediate outcrossing levels. Applied to nine populations of wheat, this method gave estimates of t0 and tp. These estimates confirmed the absence of outcrossing (t0 = 0) in the two populations subjected to manual selfing. For free-mating wheat populations, it detected lower final generation outcrossing rates (t0 = 0-0.06) than those expected from global heterozygosity (t = 0.02-0.09). This estimator appears to be a new and efficient way to describe the multilocus heterozygosity of a population, complementary to Fis and progeny analysis approaches.

scholarly journals Large-Scale Analysis of the Spatiotemporal Changes of Net Ecosystem Production in Hindu Kush Himalayan Region

2021 ◽  
Vol 13 (6) ◽  
pp. 1180
Author(s):  
Da Guo ◽  
Xiaoning Song ◽  
Ronghai Hu ◽  
Xinming Zhu ◽  
Yazhen Jiang ◽  
...  
Keyword(s):  
Large Scale ◽  
Net Primary Production ◽  
Carbon Sink ◽  
Carbon Sources ◽  
Spatial Dynamics ◽  
Tibet Plateau ◽  
Geostatistical Model ◽  
Hindu Kush ◽  
Temporal And Spatial ◽  
The Difference

The Hindu Kush Himalayan (HKH) region is one of the most ecologically vulnerable regions in the world. Several studies have been conducted on the dynamic changes of grassland in the HKH region, but few have considered grassland net ecosystem productivity (NEP). In this study, we quantitatively analyzed the temporal and spatial changes of NEP magnitude and the influence of climate factors on the HKH region from 2001 to 2018. The NEP magnitude was obtained by calculating the difference between the net primary production (NPP) estimated by the Carnegie–Ames Stanford Approach (CASA) model and the heterotrophic respiration (Rh) estimated by the geostatistical model. The results showed that the grassland ecosystem in the HKH region exhibited weak net carbon uptake with NEP values of 42.03 gC∙m−2∙yr−1, and the total net carbon sequestration was 0.077 Pg C. The distribution of NEP gradually increased from west to east, and in the Qinghai–Tibet Plateau, it gradually increased from northwest to southeast. The grassland carbon sources and sinks differed at different altitudes. The grassland was a carbon sink at 3000–5000 m, while grasslands below 3000 m and above 5000 m were carbon sources. Grassland NEP exhibited the strongest correlation with precipitation, and it had a lagging effect on precipitation. The correlation between NEP and the precipitation of the previous year was stronger than that of the current year. NEP was negatively correlated with temperature but not with solar radiation. The study of the temporal and spatial dynamics of NEP in the HKH region can provide a theoretical basis to help herders balance grazing and forage.

scholarly journals Genome-Wide Analyses Identifies Known and New Markers Responsible of Chicken Plumage Color

Animals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 493
Author(s):  
Salvatore Mastrangelo ◽  
Filippo Cendron ◽  
Gianluca Sottile ◽  
Giovanni Niero ◽  
Baldassare Portolano ◽  
...  
Keyword(s):  
Genome Wide Association Study ◽  
Snp Array ◽  
Fixation Index ◽  
Phenotypic Traits ◽  
Plumage Color ◽  
Phenotypic Marker ◽  
Genome Wide ◽  
A Genome ◽  
The Difference ◽  
Genomic Regions

Through the development of the high-throughput genotyping arrays, molecular markers and genes related to phenotypic traits have been identified in livestock species. In poultry, plumage color is an important qualitative trait that can be used as phenotypic marker for breed identification. In order to assess sources of genetic variation related to the Polverara chicken breed plumage colour (black vs. white), we carried out a genome-wide association study (GWAS) and a genome-wide fixation index (FST) scan to uncover the genomic regions involved. A total of 37 animals (17 white and 20 black) were genotyped with the Affymetrix 600 K Chicken single nucleotide polymorphism (SNP) Array. The combination of results from GWAS and FST revealed a total of 40 significant markers distributed on GGA 01, 03, 08, 12 and 21, and located within or near known genes. In addition to the well-known TYR, other candidate genes have been identified in this study, such as GRM5, RAB38 and NOTCH2. All these genes could explain the difference between the two Polverara breeds. Therefore, this study provides the basis for further investigation of the genetic mechanisms involved in plumage color in chicken.

scholarly journals Genetic Relationships Among Representatives of Dasypyrum, Secale and Triticum Species Revealed with RAPD and ISSR Markers

2014 ◽  
Vol 42 (2) ◽  
pp. 420-430
Author(s):  
Agnieszka GRADZIELEWSKA ◽  
Mirosław TYRKA ◽  
Justyna LESNIOWSKA-NOWAK ◽  
Justyna NAZARUK
Keyword(s):  
Gene Diversity ◽  
Genetic Relationships ◽  
Issr Markers ◽  
Genetic Distances ◽  
Fixation Index ◽  
Triticum Species ◽  
The Difference ◽  
Bridge Species ◽  
Differentiation Gene ◽  
Rapd And Issr

In this study the genetic similarity among Dasypyrum, Secale andTriticum species with RAPDs and ISSRs was analyzed. To show a level of similarity between the species, 12 populations of Dasypyrum (11 D. villosum and 1 D. breviaristatum), together with 12 accessions belonging to 3 Secale species and 12 accessions from 4 Triticum species were used. Genetic distances (GD) and bootstrap values were calculated and PCA analysis was conducted to present the relationships among the species. To estimate the genetic structure among and inside genera, as well as population differentiation, gene diversity (He), total genetic variation (Ht) and Wright’s fixation index (Fst) were computed. The highest values were found in Triticum, within which Ht was equal to 0.332±0.023 and Fst was 0.42. It confirmed that the material studied was highly differentiated. Both systems found Dasypyrum more related with Triticum, as compared to Secale. With RAPDs, genetic distance (GD) between Triticum and Dasypyrum was 0.435, respectively 0.460 for Secale vs Dasypyrum. In the case of ISSRs these values were 0.374 and 0.407, respectively. Despite the fact that the difference between the two GD indices was insignificant, one should not exclude the possibility of successful hybridization of Dasypyrum and Secale, especially when using bridge species.

scholarly journals Forest fires and climate-induced tree range shifts in the western US

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Avery P. Hill ◽  
Christopher B. Field
Keyword(s):  
Climate Change ◽  
Forest Fires ◽  
Fire Management ◽  
Range Shifts ◽  
Inventory Analysis ◽  
Plant Populations ◽  
Wildfire Occurrence ◽  
Western Us ◽  
The Difference ◽  
Climate Space

AbstractDue to climate change, plant populations experience environmental conditions to which they are not adapted. Our understanding of the next century’s vegetation geography depends on the distance, direction, and rate at which plant distributions shift in response to a changing climate. In this study we test the sensitivity of tree range shifts (measured as the difference between seedling and mature tree ranges in climate space) to wildfire occurrence, using 74,069 Forest Inventory Analysis plots across nine states in the western United States. Wildfire significantly increased the seedling-only range displacement for 2 of the 8 tree species in which seedling-only plots were displaced from tree-plus-seedling plots in the same direction with and without recent fire. The direction of climatic displacement was consistent with that expected for warmer and drier conditions. The greater seedling-only range displacement observed across burned plots suggests that fire can accelerate climate-related range shifts and that fire and fire management will play a role in the rate of vegetation redistribution in response to climate change.

CH4 Emissions Reduction Potential of Rice Paddy Ecosystem in South Jiangsu Province

2013 ◽  
Vol 734-737 ◽  
pp. 1820-1823
Author(s):  
Lei Zhong ◽  
Hui Zou ◽  
Xin Hao
Keyword(s):  
Reduction Potential ◽  
Rice Paddy ◽  
Jiangsu Province ◽  
Emissions Reduction ◽  
Temporal And Spatial Variation ◽  
Growing Seasons ◽  
Paddy Ecosystem ◽  
Variation Characteristics ◽  
Temporal And Spatial ◽  
The Difference

Estimating the reduction potential of methane (CH4) emissions in order to provide some advices for reducing them in paddy ecosystem. In order to study the temporal and spatial variation characteristics and the reduction potential of CH4emissions, conducting a database of CH4emissions of rice growing seasons and rice growing area in the study area. From 2001 to 2010, both the rice growing area and the CH4emission of south Jiangsu province shown a declining trend. In these 10 years, total CH4emissions decreased by 29.90×1010g, a drop of 30.72%. Base on the rice growing area in 2010, the total reduction potential of CH4emissions was 46.18×1010g in south Jiangsu province. From 2001 to 2010, the difference of CH4emissions per unit area between the cities were not big, their CH4emissions reduction was mainly due to a reduction of rice growing area.

Implications of Spatio-Temporal Variation in Forage Production and Utilization for Animal Productivity in Extensive Grazing Systems.

1998 ◽  
Vol 20 (1) ◽  
pp. 3 ◽  
Author(s):  
DA Roshier ◽  
HI Nicol
Keyword(s):  
Temporal Variation ◽  
Management Practice ◽  
Animal Production ◽  
Forage Production ◽  
Forage Availability ◽  
Typical Experiment ◽  
Grazing Systems ◽  
Spatio Temporal ◽  
The Difference ◽  
Plant Animal Interactions

In this paper we examine patterns of utilisation at the level of individual plants and forage availability at the paddock scale on five commercial sheep grazing properties that all experienced drought during the course of the study. Specifically, patterns of forage availability and pasture utilisation in large paddocks are examined against the assumptions of established models of animal productivity and grazing management practice. Forage resources in the rangelands can have dynamics independent of stock density and are not distributed evenly in time or space. Therefore, the extrapolation of known plant-animal interactions across scales is questionable and it is yet to be demonstrated how measures of animal productivity on small trial paddocks relate to production outcomes in large paddocks. A model is proposed for understanding animal production outcomes that incorporates variation in both pasture biomass and stock density. The scales, both spatial and temporal, at which pastoralists and scientists integrate ecological and animal productivity information usually differ. The understanding that each holds of the processes that limit animal productivity and the relationships between different elements of the production system is a product of the perspective from which they view the system. It is concluded that the difference between the 'scale of exploitation' and the scale at which heterogeneity is sufficient for survival of livestock is probably crucial to determining animal production outcomes in grazing systems subject to a high degree of temporal variation in forage availability. In these systems it seems reasonable to suggest that grazing experiments that vary the 'spatial scale of exploitation' while maintaining stock density constant may give as many insights into the limitations on animal productivity as the more typical experiment that only varies stock density. Key words: grazing models, animal productivity, heterogeneity, scale, utilisation, forage availability, stocking rates.

scholarly journals A multilocus estimator of mating system parameters in plant populations

1981 ◽  
Vol 78 (2) ◽  
pp. 1298-1302 ◽  
Author(s):  
D. V. Shaw ◽  
A. L. Kahler ◽  
R. W. Allard
Keyword(s):  
Mating System ◽  
Plant Populations ◽  
System Parameters

scholarly journals Diel changes in acoustic and catch estimates of krill biomass

2009 ◽  
Vol 66 (6) ◽  
pp. 1318-1325 ◽  
Author(s):  
Yvan Simard ◽  
Marc Sourisseau
Keyword(s):  
Spatial Scales ◽  
Target Strength ◽  
Night Time ◽  
Diel Changes ◽  
Strobe Light ◽  
Light Pulses ◽  
Diel Vertical Migrations ◽  
Temporal And Spatial ◽  
The Difference ◽  
Fixed Distribution

Abstract Simard, Y., and Sourisseau, M. 2009. Diel changes in acoustic and catch estimates of krill biomass. – ICES Journal of Marine Science, 66: 1318–1325. Krill-biomass estimates can be compromised by diel variabilities in acoustic backscatter and the catch efficiencies of various nets. This paper describes an effort to quantify these variabilities at fine temporal and spatial scales during a three-day experiment at a fixed location, using high-resolution, stratified Bioness samples and echo-integration, and assuming a fixed distribution of krill orientations. Night-time catches in the krill scattering layer (SL) were 15 times the acoustic estimates. The situation was reversed during daytime, when the acoustic estimates in the SL were 5 times larger than the catches. This collectively resulted in a ±10‐dB gradual diel cycle in the difference of vertically integrated biomass from both sampling methods. Use of a strobe light on the Bioness reduced avoidance of the net by krill and significantly increased (×10) daytime catches in the SL, but had no significant effect on night-time catches. The difference in volume-backscattering strength at 120 and 38 kHz (ΔSv120–38) in the densest parts of the SL agreed with predictions using a target-strength (TS) model and an assumed normal distribution of tilt (mean θ = 11°; s.d. = 4°). The ΔSv120–38 was smaller for lower densities and during night-time. It appears that the θ and, therefore, TS distributions of krill significantly change during their diel vertical migrations. At twilight and at night, when they are feeding and swimming vertically, they exhibit lower mean TS and ΔSv120–38 and react less to strong strobe-light pulses, in contrast to daytime. Diel patterns in TS and net avoidance should be taken into account in krill-biomass assessments that use round the clock acoustic-survey data and multi-frequency TS models for target classification.

Spatio-temporal variation in NPP and correlation analysis with aerosol loading and PAR in China during 2001-2017

2020 ◽  
Author(s):  
Xin Li ◽  
Weiming Cheng
Keyword(s):  
Temporal Variation ◽  
Net Primary Productivity ◽  
Terrestrial Ecosystems ◽  
Terrestrial Vegetation ◽  
Significance Level ◽  
Aerosol Loading ◽  
Western Yunnan ◽  
Growth Respiration ◽  
Spatio Temporal ◽  
The Difference

<p>The net primary productivity (NPP) reflects the growth or production of terrestrial vegetation and plays an important role in the carbon cycle on the earth. It quantifies the difference between the organic matter produced by photosynthesis and the loss of maintenance and growth respiration. The investigation of the spatio-temporal variation in NPP is significant for monitoring plant photosynthesis and carbon uptake in terrestrial ecosystems. In this study, the variability and trend of NPP in China during 2001-2017 are analysed using level 4 MODIS product (MOD17A2H). Additionally, to explore whether the NPP change in recent decades are related with the photosynthetically active radiation (PAR) variation caused by increasing aerosol loading, the correlation between NPP, PAR and aerosol optical depth (AOD) are analysed at national, regional, and pixel scales. The results show that the annual mean NPP shows higher values in the southeast than in the northwest. The highest NPP level above 2.5 gCm<sup>-2</sup>day<sup>-1</sup> is mainly distributed in tropical humid regions, including Zhejiang, Fujian, Guangdong and western Yunnan. The NPP increases with an amplitude of 0.131 gCm<sup>-2</sup>day<sup>-1</sup> during the study period. The forests have higher mean levels of NPP (1.808 gCm<sup>-2</sup>day<sup>-1</sup>) and larger increasing magnitudes (0.35 gCm<sup>-2</sup>day<sup>-1</sup>) than those of croplands and grasslands. The NPP and AOD show a negative correlation (-0.6<R<-0.2) at a significance level of 0.05 over the middle area of China. The PAR direct and diffuse components generally have positive (0<R<sub>PARdir_NPP</sub><0.6) and negative correlations (-0.6<R<sub>PARdif_NPP</sub><0) with NPP, respectively, in most of China except the northeast and Tibetan Plateau. The NPP have stronger correlations (0.215 and -0.218) with the direct and diffuse PAR in forests than in croplands and grasslands, implying that NPP is more sensitive to the change in PAR in forests than in other vegetation cover types.</p>

Sign in / Sign up

Export Citation Format

Share Document