Spatial and temporal dynamics of Puccinia andropogonis on Comandra umbellata and Andropogon gerardii in a native prairie

2005 ◽  
Vol 83 (9) ◽  
pp. 1159-1173 ◽  
Author(s):  
Charles W. Barnes ◽  
Linda L. Kinkel ◽  
James V. Groth
Keyword(s):  
Disease Severity ◽  
Temporal Dynamics ◽  
Common Garden ◽  
Andropogon Gerardii ◽  
Coefficient Of Determination ◽  
Big Bluestem ◽  
Native Prairie ◽  
Spatial And Temporal Dynamics ◽  
Rust Severity ◽  
One Year

The rust Puccinia andropogonis (Schwein.) was studied on its aecial and telial plant hosts, comandra ( Comandra umbellata L. Nutt.) and big bluestem ( Andropogon gerardii Vitman), respectively, in a native prairie to investigate the influence of aecial host proximity on disease severity of the telial host in a natural system. Both hosts were mapped to measure distances from comandra clones to selected big bluestem plants in a Minnesota prairie. Mean rust severity on big bluestem was regressed on the number of aecia on comandra (aecial density) within eight distance intervals from big bluestem plants. Distance intervals were analyzed both inclusive and exclusive of other distance intervals. There was a significant positive relationship between aecial density on comandra and rust severity on big bluestem that decreased with increasing distance in accordance with the power law model, becoming nonsignificant at distances >40 m. To establish whether the genetic background of big bluestem influenced the relationship between rust severity and the distance to comandra, a common garden was planted with a representative big bluestem plant population. The low coefficient of determination (r2) between mean rust severities of individual plants from one year to another suggests there is not a strong genetic component in the host determining disease severity.

scholarly journals Spatial and Temporal Dynamics of Mal Secco Disease Spread in Lemon Orchards in Israel

2020 ◽  
Vol 110 (4) ◽  
pp. 863-872
Author(s):  
Miriam Ben-Hamo ◽  
David Ezra ◽  
Helena Krasnov ◽  
Lior Blank
Keyword(s):  
Disease Severity ◽  
Temporal Dynamics ◽  
Disease Incidence ◽  
Disease Spread ◽  
Tree Structures ◽  
Spatial And Temporal Dynamics ◽  
Geographical Regions ◽  
Orchard Management ◽  
Severity Of The Disease ◽  
Mal Secco

Mal Secco is a severe disease of citrus in which the fungus Plenodomus tracheiphilus (formerly Phoma tracheiphila) penetrates the vascular system of the host. In this study, we characterized the spatial dynamics of the disease in seven lemon orchards. A representative block of trees from each orchard was evaluated monthly during 3 consecutive years. In addition, scouts assessed disease severity in 75 orchards from three different geographical regions and tested for association between disease severity and measures of orchard management, environmental factors, cultural practices, and cultivar type. We assessed disease incidence and characteristics of spatial patterns using Ripley’s K function and fitted logistic regression models for different neighboring tree structures followed by model selection methods to provide insight into the spatial and temporal dynamics of disease progress. We found different rates of disease spread in different orchards, which are most likely the result of differences in orchard management practices or less likely the result of differences in climatic conditions. There was an indication that agricultural tools contribute to spread of the disease within rows of trees. The results confirm that the lemon cultivar Interdonato is less susceptible compared with other citrus cultivars, and they suggest that the density of urban terrain surrounding each orchard is positively correlated with the severity of the disease. In contrast to our expectations, no correlation was found between the density of lemon orchards surrounding an orchard and the severity of the disease within it, which corroborates previous findings regarding the limited distribution of the disease.

scholarly journals Spatial and temporal dynamics of dengue fever in Peru: 1994–2006

2008 ◽  
Vol 136 (12) ◽  
pp. 1667-1677 ◽  
Author(s):  
G. CHOWELL ◽  
C. A. TORRE ◽  
C. MUNAYCO-ESCATE ◽  
L. SUÁREZ-OGNIO ◽  
R. LÓPEZ-CRUZ ◽  
...  
Keyword(s):  
South America ◽  
Temporal Dynamics ◽  
Reproduction Number ◽  
Small Population ◽  
Coefficient Of Determination ◽  
Climatological Data ◽  
Pareto Distributions ◽  
Spatial And Temporal Dynamics ◽  
High Degree ◽  
Dengue Epidemic

SUMMARYThe weekly number of dengue cases in Peru, South America, stratified by province for the period 1994–2006 were analysed in conjunction with associated demographic, geographic and climatological data. Estimates of the reproduction number, moderately correlated with population size (Spearman ρ=0·28, P=0·03), had a median of 1·76 (IQR 0·83–4·46). The distributions of dengue attack rates and epidemic durations follow power-law (Pareto) distributions (coefficient of determination >85%, P<0·004). Spatial heterogeneity of attack rates was highest in coastal areas followed by mountain and jungle areas. Our findings suggest a hierarchy of transmission events during the large 2000–2001 epidemic from large to small population areas when serotypes DEN-3 and DEN-4 were first identified (Spearman ρ=−0·43, P=0·03). The need for spatial and temporal dengue epidemic data with a high degree of resolution not only increases our understanding of the dynamics of dengue but will also generate new hypotheses and provide a platform for testing innovative control policies.

Distribution of polyploid variation in big bluestem (Andropogon gerardii, Poaceae) across the tallgrass prairie region

Genome ◽  
1990 ◽  
Vol 33 (1) ◽  
pp. 95-100 ◽  
Author(s):  
Kathleen H. Keeler
Keyword(s):  
Tallgrass Prairie ◽  
Nuclear Dna ◽  
Missouri River ◽  
Andropogon Gerardii ◽  
Big Bluestem ◽  
Native Prairie ◽  
Dna Values ◽  
River Plants ◽  
Prairie West ◽  
East West

The objective of this research was to describe the distribution of polyploid cytotypes of the grass big bluestem (Andropogon gerardii Vitman) along an east–west transect across the tallgrass prairie region, as an integral part of understanding the function of intraspecific polyploid polymorphism. Andropogon gerardii shows intraspecific variation in amount of nuclear DNA as a result of intraspecific polyploidy. Nearly 600 plants from 15 prairies in 5 states were collected and nuclear DNA was determined by flow cytometry. In the eastern part of the tallgrass prairie region, higher polyploids were rarely found. However, at the western edge of the tallgrass prairie, west of the Missouri River, plants with high nuclear DNA values comprised about half of the plants sampled and in one native prairie formed 82% of the population. Although big bluestem is historically the dominant grass throughout this region, it is extremely variable only on the western extreme of region.Key words: polyploidy, polymorphism, big bluestem, Poaceae, Andropogon gerardii, tallgrass prairie.

Drought tolerance in ecotypes of big bluestem (Andropogon gerardii) relates to above-ground surface area: Results from a common garden experiment

Flora ◽  
2018 ◽  
Vol 246-247 ◽  
pp. 52-60 ◽  
Author(s):  
Diedre L. Kramer ◽  
Keri L. Maricle ◽  
Christina J. Hilt ◽  
Nicole M. Martin ◽  
Adam D. Urban ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Surface Area ◽  
Ground Surface ◽  
Common Garden ◽  
Andropogon Gerardii ◽  
Big Bluestem ◽  
Common Garden Experiment

Spatial and temporal dynamics of lexico-semantic processing in American Sign Language

2011 ◽  
Author(s):  
M. Leonard ◽  
N. Ferjan Ramirez ◽  
C. Torres ◽  
M. Hatrak ◽  
R. Mayberry ◽  
...  
Keyword(s):  
American Sign Language ◽  
Sign Language ◽  
Semantic Processing ◽  
Temporal Dynamics ◽  
American Sign ◽  
Spatial And Temporal Dynamics

Spatial and temporal dynamics of Pacific capelin Mallotus catervarius in the Gulf of Alaska: implications for ecosystem-based fisheries management

2020 ◽  
Vol 637 ◽  
pp. 117-140 ◽  
Author(s):  
DW McGowan ◽  
ED Goldstein ◽  
ML Arimitsu ◽  
AL Deary ◽  
O Ormseth ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Marine Ecosystem ◽  
Gulf Of Alaska ◽  
Data Series ◽  
Limited Information ◽  
Important Species ◽  
Multiple Data ◽  
Spatial And Temporal Dynamics ◽  
Spawning Areas ◽  
Spatio Temporal

Pacific capelin Mallotus catervarius are planktivorous small pelagic fish that serve an intermediate trophic role in marine food webs. Due to the lack of a directed fishery or monitoring of capelin in the Northeast Pacific, limited information is available on their distribution and abundance, and how spatio-temporal fluctuations in capelin density affect their availability as prey. To provide information on life history, spatial patterns, and population dynamics of capelin in the Gulf of Alaska (GOA), we modeled distributions of spawning habitat and larval dispersal, and synthesized spatially indexed data from multiple independent sources from 1996 to 2016. Potential capelin spawning areas were broadly distributed across the GOA. Models of larval drift show the GOA’s advective circulation patterns disperse capelin larvae over the continental shelf and upper slope, indicating potential connections between spawning areas and observed offshore distributions that are influenced by the location and timing of spawning. Spatial overlap in composite distributions of larval and age-1+ fish was used to identify core areas where capelin consistently occur and concentrate. Capelin primarily occupy shelf waters near the Kodiak Archipelago, and are patchily distributed across the GOA shelf and inshore waters. Interannual variations in abundance along with spatio-temporal differences in density indicate that the availability of capelin to predators and monitoring surveys is highly variable in the GOA. We demonstrate that the limitations of individual data series can be compensated for by integrating multiple data sources to monitor fluctuations in distributions and abundance trends of an ecologically important species across a large marine ecosystem.

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