1,462 research outputs found
The global spread of crop pests and pathogens
AcceptedArticle in PressCopyright © 2014 The Authors. Global Ecology and Biogeography published by John Wiley & Sons Ltd.Aim: To describe the patterns and trends in the spread of crop pests and pathogens around the world, and determine the socioeconomic, environmental and biological factors underlying the rate and degree of redistribution of crop-destroying organisms. Location: Global. Methods: Current country- and state-level distributions of 1901 pests and pathogens and historical observation dates for 424 species were compared with potential distributions based upon distributions of host crops. The degree of 'saturation', i.e. the fraction of the potential distribution occupied, was related to pest type, host range, crop production, climate and socioeconomic variables using linear models. Results: More than one-tenth of all pests have reached more than half the countries that grow their hosts. If current trends continue, many important crop-producing countries will be fully saturated with pests by the middle of the century. While dispersal increases with host range overall, fungi have the narrowest host range but are the most widely dispersed group. The global dispersal of some pests has been rapid, but pest assemblages remain strongly regionalized and follow the distributions of their hosts. Pest assemblages are significantly correlated with socioeconomics, climate and latitude. Tropical staple crops, with restricted latitudinal ranges, tend to be more saturated with pests and pathogens than temperate staples with broad latitudinal ranges. We list the pests likely to be the most invasive in coming years. Main conclusions: Despite ongoing dispersal of crop pests and pathogens, the degree of biotic homogenization of the globe remains moderate and regionally constrained, but is growing. Fungal pathogens lead the global invasion of agriculture, despite their more restricted host range. Climate change is likely to influence future distributions. Improved surveillance would reveal greater levels of invasion, particularly in developing countries. © 2014 John Wiley & Sons Ltd.BBSR
Economic and physical determinants of the global distributions of crop pests and pathogens.
© 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.Crop pests and pathogens pose a significant and growing threat to food security, but their geographical distributions are poorly understood. We present a global analysis of pest and pathogen distributions, to determine the roles of socioeconomic and biophysical factors in determining pest diversity, controlling for variation in observational capacity among countries. Known distributions of 1901 pests and pathogens were obtained from CABI. Linear models were used to partition the variation in pest species per country amongst predictors. Reported pest numbers increased with per capita gross domestic product (GDP), research expenditure and research capacity, and the influence of economics was greater in micro-organisms than in arthropods. Total crop production and crop diversity were the strongest physical predictors of pest numbers per country, but trade and tourism were insignificant once other factors were controlled. Islands reported more pests than mainland countries, but no latitudinal gradient in species richness was evident. Country wealth is likely to be a strong indicator of observational capacity, not just trade flow, as has been interpreted in invasive species studies. If every country had US levels of per capita GDP, then 205 ± 9 additional pests per country would be reported, suggesting that enhanced investment in pest observations will reveal the hidden threat of crop pests and pathogens.BBSR
Economic and physical determinants of the global distributions of crop pests and pathogens
Crop pests and pathogens pose a significant and growing threat to food security, but their geographical distributions are poorly understood. We present a global analysis of pest and pathogen distributions, to determine the roles of socioeconomic and biophysical factors in determining pest diversity, controlling for variation in observational capacity among countries. Known distributions of 1901 pests and pathogens were obtained from CABI. Linear models were used to partition the variation in pest species per country amongst predictors. Reported pest numbers increased with per capita gross domestic product (GDP), research expenditure and research capacity, and the influence of economics was greater in micro-organisms than in arthropods. Total crop production and crop diversity were the strongest physical predictors of pest numbers per country, but trade and tourism were insignificant once other factors were controlled. Islands reported more pests than mainland countries, but no latitudinal gradient in species richness was evident. Country wealth is likely to be a strong indicator of observational capacity, not just trade flow, as has been interpreted in invasive species studies. If every country had US levels of per capita GDP, then 205 +/- 9 additional pests per country would be reported, suggesting that enhanced investment in pest observations will reveal the hidden threat of crop pests and pathogens
Cliophysics: Socio-political Reliability Theory, Polity Duration and African Political (In)stabilities
Quantification of historical sociological processes have recently gained
attention among theoreticians in the effort of providing a solid theoretical
understanding of the behaviors and regularities present in sociopolitical
dynamics. Here we present a reliability theory of polity processes with
emphases on individual political dynamics of African countries. We found that
the structural properties of polity failure rates successfully capture the risk
of political vulnerability and instabilities in which 87.50%, 75%, 71.43%, and
0% of the countries with monotonically increasing, unimodal, U-shaped and
monotonically decreasing polity failure rates, respectively, have high level of
state fragility indices. The quasi-U-shape relationship between average polity
duration and regime types corroborates historical precedents and explains the
stability of the autocracies and democracies.Comment: 4 pages, 3 figures, 1 tabl
Who is to blame? The relationship between ingroup identification and relative deprivation is moderated by ingroup attributions
Contradictory evidence can be found in the literature about whether ingroup identification and perceived relative deprivation are positively or negatively related. Indeed, theoretical arguments can be made for both effects. It was proposed that the contradictory findings can be explained by considering a hitherto unstudied moderator: The extent to which deprivation is attributed to the ingroup. It was hypothesised that identification would only have a negative impact on deprivation, and that deprivation would only have a negative impact on identification, if ingroup attributions are high. To test this, attributions to the ingroup were experimentally manipulated among British student participants (N = 189) who were asked about their perceived deprivation vis-à-vis German students, yield ing support for the hypotheses
Large-Area Liquid Scintillation Detector Slab
A low-cost detector 18' x 2' x 5" has been developed for an underground cosmic ray neutrino experiment. The liquid employed is a high-clarity mineral oil-based mixture, and light is guided to the ends of the detector by total internal reflection at the surface of the Lucite container. Signals from 2 five-inch photomultipliers at each end give energy and event location for single penetrating particles, with relatively good discrimination against natural radioactivity by virtue of the substantial thickness. Data are presented on the response function of the tank, energy resolution, rates and thresholds. A number of modifications that have been tried are also described
Economic Backwardness and Social Tension
We propose that relative economic backwardness contributes to the build-up of social tension and non-violent and violent conflict. We test our hypothesis using data on organized mass movements and armed civil conflict. The findings show that greater economic backwardness is consistently linked to a higher probability of onset of violent and especially non-violent forms of civil unrest. We provide evidence that the relationship is causal in instrumental variables estimations using new instruments, including mailing speeds and telegram charges around 1900. The magnitude of the effect of backwardness on social tension increases in the two-stage least-squares estimations
Citizens, bribery and the propensity to protest
It is widely assumed that the more one experiences corruption the more likely one is to want to protest about it. Yet empirical evidence illustrating this is thin on the ground. This paper fills that gap by focusing on the extent to which self-reported experience of bribery affects the willingness to engage in protests against corruption in Africa. We find that the more one experiences bribery the more one is likely to support anti-corruption protests. A further unexpected finding is that the personal experience of corruption also increases the willingness to rely on bribes to solve public administration problems
Many unreported crop pests and pathogens are probably already present
This is the final version. Available from on open access Wiley via the DOI in this record. Data availability statement: Pest distribution data are available with permission from CABI, Nosworthy Way, Wallingford OX10 8DE, UK. Sources for other data sets used in the analysis are given in the text.Invasive species threaten global biodiversity, food security and ecosystem function. Such incursions present challenges to agriculture where invasive species cause significant crop damage and require major economic investment to control production losses. Pest risk analysis (PRA) is key to prioritize agricultural biosecurity efforts, but is hampered by incomplete knowledge of current crop pest and pathogen distributions. Here, we develop predictive models of current pest distributions and test these models using new observations at subnational resolution. We apply generalized linear models (GLM) to estimate presence probabilities for 1,739 crop pests in the CABI pest distribution database. We test model predictions for 100 unobserved pest occurrences in the People's Republic of China (PRC), against observations of these pests abstracted from the Chinese literature. This resource has hitherto been omitted from databases on global pest distributions. Finally, we predict occurrences of all unobserved pests globally. Presence probability increases with host presence, presence in neighbouring regions, per capita GDP and global prevalence. Presence probability decreases with mean distance from coast and known host number per pest. The models are good predictors of pest presence in provinces of the PRC, with area under the ROC curve (AUC) values of 0.75-0.76. Large numbers of currently unobserved, but probably present pests (defined here as unreported pests with a predicted presence probability >0.75), are predicted in China, India, southern Brazil and some countries of the former USSR. We show that GLMs can predict presences of pseudoabsent pests at subnational resolution. The Chinese literature has been largely inaccessible to Western academia but contains important information that can support PRA. Prior studies have often assumed that unreported pests in a global distribution database represent a true absence. Our analysis provides a method for quantifying pseudoabsences to enable improved PRA and species distribution modelling.British Society for Plant PathologyCentre for Agriculture and Bioscience Internationa
Satisfaction with democracy and voter turnout
Numerous studies conclude that countries in which citizens express higher levels of satisfaction with democracy also tend to display higher levels of voter turnout in national elections. Yet it is difficult to draw causal inferences from this positive cross-sectional relationship, because democracies feature many historical, cultural, and institutional differences that are not easily controlled for in cross-sectional comparisons. We apply an alternative, temporal approach to this issue by asking the question: Are over-time declines (increases) in aggregate levels of satisfaction within democracies associated with increases (declines) in levels of voter turnout within these democracies? Our temporal analysis of this relationship in 12 democracies over the period 1976–2011 reveals a pattern that is the opposite of that suggested by previous cross-sectional studies: namely, we find that over-time increases in citizens’ satisfaction with democracy are associated with significant decreases in voter turnout in national elections in these countries. </jats:p
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