scholarly journals The nectar report: quantitative review of nectar sugar concentrations offered by bee visited flowers in agricultural and non-agricultural landscapes

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6329 ◽  
Author(s):  
Tobias Pamminger ◽  
Roland Becker ◽  
Sophie Himmelreich ◽  
Christof W. Schneider ◽  
Matthias Bergtold
Keyword(s):  
Plant Community ◽  
Nutritional Stress ◽  
Agricultural Landscapes ◽  
Wild Plant ◽  
Weed Species ◽  
Data Set ◽  
Social Bees ◽  
Starting Point ◽  
Nectar Sugar ◽  
Flower Resources

There is growing concern that some bee populations are in decline, potentially threatening pollination security in agricultural and non-agricultural landscapes. Among the numerous causes associated with this trend, nutritional stress resulting from a mismatch between bee nutritional needs and plant community provisioning has been suggested as one potential driver. To ease nutritional stress on bee populations in agricultural habitats, agri-environmental protection schemes aim to provide alternative nutritional resources for bee populations during times of need. However, such efforts have focused mainly on quantity (providing flowering plants) and timing (during flower-scarce periods), while largely ignoring the quality of the offered flower resources. In a first step to start addressing this information gap, we have used literature data to compile a comprehensive geographically explicit dataset on nectar quality (i.e., total sugar concentration), offered to bees both within fields (crop and weed species) as well as outside fields (wild species) around the globe. Social bees are particularly sensitive to nectar sugar concentrations, which directly impact calorie influx into the colony and consequently their fitness making it an important resource quality marker. We find that the total nectar sugar concentrations in general do not differ between the three plant communities studied. In contrast we find increased variability in nectar quality in the wild plant community compared to crop and weed community, which is likely explained by the increased phylogenetic diversity in this category of plants. In a second step we explore the influence of local habitat on nectar quality and its variability utilizing a detailed sunflower (Helianthus annuus L.) data set and find that geography has a small, but significant influence on these parameters. In a third step we identify crop groups (genera), which provide sub-optimal nectar resources for bees and suggest high quality alternatives as potential nectar supplements. In the long term this data set could serve as a starting point to systematically collect more quality characteristics of plant provided resources to bees, which ultimately can be utilized by scientist, regulators, NGOs and farmers to improve the flower resources offered to bees. We hope that ultimately this data will help to ease nutritional stress for bee populations and foster a data informed discussion about pollinator conservation in modern agricultural landscapes.

scholarly journals The nectar report: Quantitative review of nectar sugar concentrations offered by bee visited flowers in agricultural and non-agricultural landscapes

2018 ◽  
Author(s):  
Tobias Pamminger ◽  
Roland Becker ◽  
Sophie Himmelreich ◽  
Christof W Schneider ◽  
Matthias Bergtold
Keyword(s):  
Plant Community ◽  
Nutritional Stress ◽  
Agricultural Landscapes ◽  
Wild Plant ◽  
Weed Species ◽  
Data Set ◽  
Starting Point ◽  
In The Wild ◽  
Nectar Sugar ◽  
Flower Resources

There is growing concern that some bee populations are in decline potentially threatening pollination security in agricultural and non-agricultural landscapes. Among the numerous causes associated with this trend nutritional stress, resulting from a mismatch between bee nutritional needs and plant community provisioning, has been suggested as one potential driver. To ease nutritional stress on bee populations in agricultural habitats, agri-environmental protection schemes aim to provide alternative nutritional resources for bee populations during times of need. However, such efforts have focused mainly on quantity (providing flowering plants) and timing (flower-scarce periods), while largely ignoring the quality of the offered flower resources. In a first step to start addressing this information gap we have compiled a comprehensive geographically explicit dataset on nectar quality (i.e. total sugar concentration), offered to bees both within fields (crop and weed species) as well as off field (wild) around the globe. We find that the total nectar sugar concentrations in general do not differ between the three plant communities studied. In contrast we find increased quality variability in the wild plant community compared to crop and weed community, which is likely explained by the increased phylogenetic diversity in this category of plants. In a second step we explore the influence of local habitat on nectar quality and its variability utilizing a detailed sunflower (Helianthus annuus L.) data set and find that geography has a small, but significant influence on these parameters. In a third step we identify crop groups (genera), which provide sub-optimal nectar resources for bees and suggest high quality alternatives as potential nectar supplements. In the long term this data base could serve as a starting point to systematically collect more quality characteristics of plant provided resources to bees, which ultimately can be utilized by scientist, regulators, NGOs and farmers to improve the flower resources offered to bees. We hope that ultimately this data will help to ease nutritional stress for bee populations and foster a data informed discussion about pollinator conservation in modern agricultural landscapes.

scholarly journals The nectar report: Quantitative review of nectar sugar concentrations offered by bee visited flowers in agricultural and non-agricultural landscapes

2018 ◽  
Author(s):  
Tobias Pamminger ◽  
Roland Becker ◽  
Sophie Himmelreich ◽  
Christof W Schneider ◽  
Matthias Bergtold
Keyword(s):  
Plant Community ◽  
Nutritional Stress ◽  
Agricultural Landscapes ◽  
Wild Plant ◽  
Weed Species ◽  
Data Set ◽  
Starting Point ◽  
In The Wild ◽  
Nectar Sugar ◽  
Flower Resources

There is growing concern that some bee populations are in decline potentially threatening pollination security in agricultural and non-agricultural landscapes. Among the numerous causes associated with this trend nutritional stress, resulting from a mismatch between bee nutritional needs and plant community provisioning, has been suggested as one potential driver. To ease nutritional stress on bee populations in agricultural habitats, agri-environmental protection schemes aim to provide alternative nutritional resources for bee populations during times of need. However, such efforts have focused mainly on quantity (providing flowering plants) and timing (flower-scarce periods), while largely ignoring the quality of the offered flower resources. In a first step to start addressing this information gap we have compiled a comprehensive geographically explicit dataset on nectar quality (i.e. total sugar concentration), offered to bees both within fields (crop and weed species) as well as off field (wild) around the globe. We find that the total nectar sugar concentrations in general do not differ between the three plant communities studied. In contrast we find increased quality variability in the wild plant community compared to crop and weed community, which is likely explained by the increased phylogenetic diversity in this category of plants. In a second step we explore the influence of local habitat on nectar quality and its variability utilizing a detailed sunflower (Helianthus annuus L.) data set and find that geography has a small, but significant influence on these parameters. In a third step we identify crop groups (genera), which provide sub-optimal nectar resources for bees and suggest high quality alternatives as potential nectar supplements. In the long term this data base could serve as a starting point to systematically collect more quality characteristics of plant provided resources to bees, which ultimately can be utilized by scientist, regulators, NGOs and farmers to improve the flower resources offered to bees. We hope that ultimately this data will help to ease nutritional stress for bee populations and foster a data informed discussion about pollinator conservation in modern agricultural landscapes.

scholarly journals A Reappraisal of the Prebisch-Singer Hypothesis Using Wavelets Analysis

2021 ◽  
Vol 14 (7) ◽  
pp. 319
Author(s):  
Hany Fahmy
Keyword(s):  
International Trade ◽  
Structural Breaks ◽  
Developing Economies ◽  
Commodity Prices ◽  
Commodity Price ◽  
Data Set ◽  
Price Series ◽  
Long Run ◽  
Starting Point ◽  
The Impact

The Prebisch-Singer (PS) hypothesis, which postulates the presence of a downward secular trend in the price of primary commodities relative to manufacturers, remains at the core of a continuing debate among international trade economists. The reason is that the results of testing the PS hypothesis depend on the starting point of the technical analysis, i.e., stationarity, nonlinearity, and the existence of structural breaks. The objective of this paper is to appraise the PS hypothesis in the short- and long-run by employing a novel multiresolution wavelets decomposition to a unique data set of commodity prices. The paper also seeks to assess the impact of the terms of trade (also known as Incoterms) on the test results. The analysis reveals that the PS hypothesis is not supported in the long run for the aggregate commodity price index and for most of the individual commodity price series forming it. Furthermore, in addition to the starting point of the analysis, the results show that the PS test depends on the term of trade classification of commodity prices. These findings are of particular significance to international trade regulators and policymakers of developing economies that depend mainly on primary commodities in their exports.

scholarly journals A new database structure for the IHFC Global Heat Flow Database

2021 ◽  
Vol 4 (1) ◽  
pp. 1-14
Author(s):  
Sven Fuchs ◽  
Graeme Beardsmore ◽  
Paolo Chiozzi ◽  
Orlando Miguel Espinoza-Ojeda ◽  
Gianluca Gola ◽  
...  
Keyword(s):  
Heat Flow ◽  
International Association ◽  
Open Data ◽  
Flow Data ◽  
Ocean Drilling Program ◽  
Data Set ◽  
Data Services ◽  
External Data ◽  
Database Structure ◽  
Starting Point

Periodic revisions of the Global Heat Flow Database (GHFD) take place under the auspices of the International Heat Flow Commission (IHFC) of the International Association of Seismology and Physics of the Earth's Interior (IASPEI). A growing number of heat-flow values, advances in scientific methods, digitization, and improvements in database technologies all warrant a revision of the structure of the GHFD that was last amended in 1976. We present a new structure for the GHFD, which will provide a basis for a reassessment and revision of the existing global heat-flow data set. The database fields within the new structure are described in detail to ensure a common understanding of the respective database entries. The new structure of the database takes advantage of today's possibilities for data management. It supports FAIR and open data principles, including interoperability with external data services, and links to DOI and IGSN numbers and other data resources (e.g., world geological map, world stratigraphic system, and International Ocean Drilling Program data). Aligned with this publication, a restructured version of the existing database is published, which provides a starting point for the upcoming collaborative process of data screening, quality control and revision. In parallel, the IHFC will work on criteria for a new quality scheme that will allow future users of the database to evaluate the quality of the collated heat-flow data based on specific criteria.

Transfer of resistance alleles from herbicide-resistant to susceptible grass weeds via pollen-mediated gene flow

2021 ◽  
pp. 1-51
Author(s):  
Amit J. Jhala ◽  
Hugh J. Beckie ◽  
Carol Mallory-Smith ◽  
Marie Jasieniuk ◽  
Roberto Busi ◽  
...  
Keyword(s):  
Gene Flow ◽  
Herbicide Resistance ◽  
Creeping Bentgrass ◽  
Agricultural Landscapes ◽  
Italian Ryegrass ◽  
Weed Species ◽  
Herbicide Resistant ◽  
Wild Oats ◽  
Rigid Ryegrass ◽  
Grass Weed

Abstract The objective of this paper was to review the reproductive biology, herbicide-resistant (HR) biotypes, pollen-mediated gene flow (PMGF), and potential for transfer of alleles from HR to susceptible grass weeds including barnyardgrass, creeping bentgrass, Italian ryegrass, johnsongrass, rigid (annual) ryegrass, and wild oats. The widespread occurrence of HR grass weeds is at least partly due to PMGF, particularly in obligate outcrossing species such as rigid ryegrass. Creeping bentgrass, a wind-pollinated turfgrass species, can efficiently disseminate herbicide resistance alleles via PMGF and movement of seeds and stolons. The genus Agrostis contains about 200 species, many of which are sexually compatible and produce naturally occurring hybrids as well as producing hybrids with species in the genus Polypogon. The self-incompatibility, extremely high outcrossing rate, and wind pollination in Italian ryegrass clearly point to PMGF as a major mechanism by which herbicide resistance alleles can spread across agricultural landscapes, resulting in abundant genetic variation within populations and low genetic differentiation among populations. Italian ryegrass can readily hybridize with perennial ryegrass and rigid ryegrass due to their similarity in chromosome numbers (2n=14), resulting in interspecific gene exchange. Johnsongrass, barnyardgrass, and wild oats are self-pollinated species, so the potential for PMGF is relatively low and limited to short distances; however, seeds can easily shatter upon maturity before crop harvest, leading to wider dispersal. The occurrence of PMGF in reviewed grass weed species, even at a low rate is greater than that of spontaneous mutations conferring herbicide resistance in weeds and thus can contribute to the spread of herbicide resistance alleles. This review indicates that the transfer of herbicide resistance alleles occurs under field conditions at varying levels depending on the grass weed species.

scholarly journals Sessile oak forest plant community changes on the NE Iberian Peninsula over recent decades

2019 ◽  
Vol 12 (5) ◽  
pp. 894-906
Author(s):  
Jordi Bou ◽  
Lluís Vilar
Keyword(s):  
Global Change ◽  
Iberian Peninsula ◽  
Plant Community ◽  
Climate Warming ◽  
Oak Forests ◽  
Oak Forest ◽  
Data Set ◽  
Sessile Oak ◽  
Ne Iberian Peninsula ◽  
Coastal Range

AbstractAimsOur aims were 3-fold: (i) to determine whether global change has altered the composition and structure of the plant community found in the sessile oak forests on the NE Iberian Peninsula over the last decades, (ii) to establish whether the decline in forest exploitation activities that has taken place since the mid-20th century has had any effect on the forests and (iii) to ascertain whether there is any evidence of impact from climate warming.MethodsWe assess changes in the plant community by comparing a current survey of sessile oak forest with a historical data set obtained from previous regional studies dating from 1962 to 1977. We analyse the regional changes in the community in terms of biodiversity variables, species composition and plant traits. Furthermore, plants traits such as plant life forms and chorological groups are used to discern any effects from land-use changes and climate warming on the plant community.Important FindingsThere has been a loss of diversity in the community and, in the hottest region, there is also a loss of species richness. The composition of the community suggests that, although significant changes have taken place over recent decades, these changes differ between regions as a result of the low impact global change has had in the western regions. For instance, while the tree canopy cover in the western sessile oak forests remains stable, the eastern sessile oak forests are still recovering from the former exploitation that led to a loss of their rich and abundant herbaceous stratum. In fact, the recovery process in the Catalan Pre-Coastal Range has constituted an increase in the Euro-Siberian plants typical to this community. Moreover, in the eastern forests, there is evidence that climate warming has impacted the thermophilization of the sessile oak forests found on the Coastal Range.

Gender Differences in the Provision of Job-Search Help

2019 ◽  
Vol 33 (5) ◽  
pp. 746-771
Author(s):  
Min Zhou
Keyword(s):  
Gender Differences ◽  
Gender Inequality ◽  
Job Search ◽  
Large Data ◽  
Direct Influence ◽  
Data Set ◽  
Social Contacts ◽  
Force Dynamics ◽  
Hiring Process ◽  
Starting Point

The existing literature has well studied the use of social contacts in job search, including gender inequality, in using social contacts. What is missing is the perspective of social contacts who help others find jobs. Using a large data set from the 2012 China Labor-Force Dynamics Survey, this study reveals significant gender differences in the provision of job-search help. Compared with women, men are more likely to provide job-search help and especially show a greater likelihood of exerting direct influence on the hiring process. While women are gender neutral in their choice of help recipients, men display a selective preference for helping other men. This men’s advantage of providing job-search help, especially influence-based help, and men’s selective preference for helping other men, imply another prominent gender inequality in informal hiring in the labor market. This study suggests several theoretical propositions to explain the revealed gender differences in both “whether to help” and “whom to help,” providing a starting point for further research.

scholarly journals Semi-automated construction of patient individualised clinical target volumes for radiotherapy treatment of glioblastoma utilising diffusion tensor decomposition maps

2020 ◽  
Vol 93 (1108) ◽  
pp. 20190441 ◽  
Author(s):  
Roushanak Rahmat ◽  
Frederic Brochu ◽  
Chao Li ◽  
Rohitashwa Sinha ◽  
Stephen John Price ◽  
...  
Keyword(s):  
Level Set ◽  
Radiation Treatment ◽  
Diffusion Tensor ◽  
Tensor Decomposition ◽  
Data Set ◽  
Tumour Spread ◽  
Starting Point ◽  
Target Volumes ◽  
Initial Starting ◽  
Level Set Model

Objectives: Glioblastoma multiforme (GBM) is a highly infiltrative primary brain tumour with an aggressive clinical course. Diffusion tensor imaging (DT-MRI or DTI) is a recently developed technique capable of visualising subclinical tumour spread into adjacent brain tissue. Tensor decomposition through p and q maps can be used for planning of treatment. Our objective was to develop a tool to automate the segmentation of DTI decomposed p and q maps in GBM patients in order to inform construction of radiotherapy target volumes. Methods: Chan-Vese level set model is applied to segment the p map using the q map as its initial starting point. The reason of choosing this model is because of the robustness of this model on either conventional MRI or only DTI. The method was applied on a data set consisting of 50 patients having their gross tumour volume delineated on their q map and Chan-Vese level set model uses these superimposed masks to incorporate the infiltrative edges. Results: The expansion of tumour boundary from q map to p map is clearly visible in all cases and the Dice coefficient (DC) showed a mean similarity of 74% across all 50 patients between the manually segmented ground truth p map and the level set automatic segmentation. Conclusion: Automated segmentation of the tumour infiltration boundary using DTI and tensor decomposition is possible using Chan-Vese level set methods to expand q map to p map. We have provided initial validation of this technique against manual contours performed by experienced clinicians. Advances in knowledge: This novel automated technique to generate p maps has the potential to individualise radiation treatment volumes and act as a decision support tool for the treating oncologist.

scholarly journals Evidence of within-species specialization by soil microbes and the implications for plant community diversity

2019 ◽  
Vol 116 (15) ◽  
pp. 7371-7376 ◽  
Author(s):  
Jenalle L. Eck ◽  
Simon M. Stump ◽  
Camille S. Delavaux ◽  
Scott A. Mangan ◽  
Liza S. Comita
Keyword(s):  
Microbial Community ◽  
Seed Dispersal ◽  
Plant Species ◽  
Plant Community ◽  
Plant Communities ◽  
Soil Microbial Community ◽  
Soil Microbes ◽  
Wild Plant ◽  
Soil Microbial ◽  
Species Specific

Microbes are thought to maintain diversity in plant communities by specializing on particular species, but it is not known whether microbes that specialize within species (i.e., on genotypes) affect diversity or dynamics in plant communities. Here we show that soil microbes can specialize at the within-population level in a wild plant species, and that such specialization could promote species diversity and seed dispersal in plant communities. In a shadehouse experiment in Panama, we found that seedlings of the native tree species, Virola surinamensis (Myristicaceae), had reduced performance in the soil microbial community of their maternal tree compared with in the soil microbial community of a nonmaternal tree from the same population. Performance differences were unrelated to soil nutrients or to colonization by mycorrhizal fungi, suggesting that highly specialized pathogens were the mechanism reducing seedling performance in maternal soils. We then constructed a simulation model to explore the ecological and evolutionary consequences of genotype-specific pathogens in multispecies plant communities. Model results indicated that genotype-specific pathogens promote plant species coexistence—albeit less strongly than species-specific pathogens—and are most effective at maintaining species richness when genetic diversity is relatively low. Simulations also revealed that genotype-specific pathogens select for increased seed dispersal relative to species-specific pathogens, potentially helping to create seed dispersal landscapes that allow pathogens to more effectively promote diversity. Combined, our results reveal that soil microbes can specialize within wild plant populations, affecting seedling performance near conspecific adults and influencing plant community dynamics on ecological and evolutionary time scales.

scholarly journals Traditional semi-natural grassland management with heterogeneous mowing times enhances flower resources for pollinators in agricultural landscapes

2019 ◽  
Vol 18 ◽  
pp. e00619 ◽  
Author(s):  
Line Johansen ◽  
Anna Westin ◽  
Sølvi Wehn ◽  
Anamaria Iuga ◽  
Cosmin Marius Ivascu ◽  
...  
Keyword(s):  
Grassland Management ◽  
Agricultural Landscapes ◽  
Flower Resources ◽  
Natural Grassland
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