scholarly journals Terrestrial mesopredators did not increase after top-predator removal in a large-scale experimental test of mesopredator release theory

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Geoff Castle ◽  
Deane Smith ◽  
Lee R. Allen ◽  
Benjamin L. Allen
Keyword(s):  
Large Scale ◽  
Open Systems ◽  
Scale Up ◽  
Population Level ◽  
Mesopredator Release ◽  
Negative Effects ◽  
Red Foxes ◽  
Feral Cats ◽  
Reliable Evidence ◽  
Manipulative Experiments

AbstractRemoval or loss of top-predators has been predicted to cause cascading negative effects for ecosystems, including mesopredator release. However, reliable evidence for these processes in terrestrial systems has been mixed and equivocal due, in large part, to the systemic and continued use of low-inference study designs to investigate this issue. Even previous large-scale manipulative experiments of strong inferential value have been limited by experimental design features (i.e. failure to prevent migration between treatments) that constrain possible inferences about the presence or absence of mesopredator release effects. Here, we build on these previous strong-inference experiments and report the outcomes of additional large-scale manipulative experiments to eradicate Australian dingoes from two fenced areas where dingo migration was restricted and where theory would predict an increase in extant European red foxes, feral cats and goannas. We demonstrate the removal and suppression of dingoes to undetectable levels over 4–5 years with no corresponding increases in mesopredator relative abundances, which remained low and stable throughout the experiment at both sites. We further demonstrate widespread absence of negative relationships between predators, indicating that the mechanism underpinning predicted mesopredator releases was not present. Our results are consistent with all previous large-scale manipulative experiments and long-term mensurative studies which collectively demonstrate that (1) dingoes do not suppress red foxes, feral cats or goannas at the population level, (2) repeated, temporary suppression of dingoes in open systems does not create mesopredator release effects, and (3) removal and sustained suppression of dingoes to undetectable levels in closed systems does not create mesopredator release effects either. Our experiments add to similar reports from North America, Asia, Europe and southern Africa which indicate that not only is there a widespread absence of reliable evidence for these processes, but there is also a large and continually growing body of experimental evidence of absence for these processes in many terrestrial systems. We conclude that although sympatric predators may interact negatively with each other on smaller spatiotemporal scales, that these negative interactions do not always scale-up to the population level, nor are they always strong enough to create mesopredator suppression or release effects.

scholarly journals Use, awareness and willingness to self-test for HIV: An analysis of cross-sectional population-based surveys in Malawi and Zimbabwe

2020 ◽  
Author(s):  
Cheryl Case Johnson ◽  
Melissa Neuman ◽  
Peter MacPherson ◽  
Augustine Choko ◽  
Caitlin Quinn ◽  
...  
Keyword(s):  
Sexual Risk ◽  
Large Scale ◽  
Scale Up ◽  
Population Level ◽  
Sociodemographic Factors ◽  
Population Based ◽  
African Countries ◽  
Cross Sectional ◽  
Self Test ◽  
Result Analysis

Abstract Background Many southern African countries are nearing the global goal to diagnose 90% of people with HIV by 2020. In 2016, 84% and 86% of people with HIV knew their status in Malawi and Zimbabwe respectively. Despite this progress, gaps remain, particularly among men (≥25 years). We investigated awareness, use and willingness to HIV self-test (HIVST) prior to large scale implementation and explored sociodemographic associations. Methods We pooled responses from two of the first cross-sectional Demographic Health Surveys to include HIVST questions: Malawi and Zimbabwe in 2015-16. Sociodemographic factors and sexual risk behaviours associated with previously testing for HIV, and awareness, past use and future willingness to self-test were investigated using univariable and multivariable logistic regression, adjusting for the sample design and limiting analysis to participants with completed questionnaire and a valid HIV result. Analysis of willingness to self-test was restricted to Zimbabwean men, as Malawians and women were not asked this question. Results Of 31 385 individuals, the proportion never-tested was higher for men (31.2%) than women (16.5%), p<0.001. For men, having ever tested increased with age. Past use and awareness of HIVST was very low, 1.2% and 12.6% respectively. Awareness was lower among women than men (9.1% vs 15.3%, adjusted odds ratio (aOR)=1.55; 95% confidence interval [CI]: 1.37-1.75), and at younger ages, and lower education and literacy levels. Willingness to self-test among Zimbabwean men was high (84.5%), with having previously tested for HIV, high sexual risk, and being ≥25 years associated with greater willingness. Wealthier men had greater awareness of HIVST than poorer men (p<0.001). Men at higher HIV-related sexual risk, compared to men at lower HIV-related sexual risk, had the greatest willingness to self-test (aOR=3.74; 95%CI: 1.39-10.03, p<0.009).Conclusions In 2015-16 many Malawian and Zimbabwean men had never tested for HIV. Despite low awareness and minimal HIVST experience at that time, willingness to self-test was high among Zimbabwean men, especially in older men with moderate to high HIV-related sexual risk. These data provide a valuable baseline against which to investigate population-level uptake of HIVST as programmes scale-up. Programmes introducing, or planning to introduce HIVST, should consider including questions in population-based surveys.

scholarly journals Molecular epidemiology of a fatal sarcoptic mange epidemic in endangered San Joaquin kit foxes (Vulpes macrotis mutica)

2020 ◽  
Author(s):  
Jaime L. Rudd ◽  
Deana L. Clifford ◽  
Brian L. Cypher ◽  
Joshua M. Hull ◽  
A. Jane Riner ◽  
...  
Keyword(s):  
Large Scale ◽  
Genetic Difference ◽  
Population Level ◽  
Sarcoptes Scabiei ◽  
Sarcoptic Mange ◽  
Canis Lupus Familiaris ◽  
Red Foxes ◽  
Kit Fox ◽  
Vulpes Macrotis ◽  
Vulpes Macrotis Mutica

Abstract Background: In 2013, sarcoptic mange, caused by Sarcoptes scabiei mites, precipitated a catastrophic decline of the formerly stable urban population of endangered San Joaquin kit foxes ( Vulpes macrotis mutica ) in Bakersfield, California, USA. In 2019, a smaller sarcoptic mange outbreak affected kit foxes 58 km southwest of Bakersfield in the town of Taft, California. To determine whether the Taft outbreak could have occurred as spillover from the Bakersfield outbreak and whether epidemic control efforts must involve not only kit foxes but also sympatric dogs ( Canis lupus familiaris ), coyotes ( Canis latrans ), and red foxes ( Vulpes vulpes ), we evaluated genotypes and gene flow among mites collected from each host species.Methods: We used 10 Sarcoptes microsatellite markers (SARM) to perform molecular typing of 445 S. scabiei mites collected from skin scrapings from twenty-two infested kit foxes, two dogs, five coyotes, and five red foxes from Bakersfield, Taft, and other nearby cities.Results: We identified 60 alleles across all SARM loci; kit fox- and red fox-derived mites were relatively monomorphic, while genetic variability was greatest in Bakersfield coyote- and dog-derived mites. AMOVA analysis documented distinct mite populations unique to hosts, with an overall F ST of 0.467. The lowest F ST (i.e. closest genetic relationship, F ST = 0.038) was between Bakersfield and Taft kit fox-derived mites while the largest genetic difference was between Ventura coyote- and Taft kit fox-derived mites (F ST = 0.843).Conclusion: These results confirm the close relationship between the Taft and Bakersfield outbreaks. The Sarcoptes host specificity suggests that, although an inter-species spillover event likely initiated the kit fox mange outbreak, mite transmission is now primarily intraspecific. Therefore, any large-scale population level intervention should focus on treating kit foxes within the city.

scholarly journals Larger workers outperform smaller workers across resource environments: an evaluation of demographic data using functional linear models

2020 ◽  
Author(s):  
Natalie Kerr ◽  
Rosemary Malfi ◽  
Neal Williams ◽  
Elizabeth Crone
Keyword(s):  
Linear Models ◽  
Demographic Data ◽  
Social Groups ◽  
Scale Up ◽  
Population Level ◽  
Plant Performance ◽  
Environmental Drivers ◽  
Functional Linear Models ◽  
Positive Effects ◽  
Manipulative Experiments

1. Behavior and organization of social groups is thought to be vital to the functioning of societies, yet the contributions of various roles within social groups towards population growth and dynamics have been difficult to quantify. A common approach to quantifying these role-based contributions is evaluating the number of individuals conducting certain roles, which ignores how behavior might scale up to effects at the population-level. Manipulative experiments are another common approach to determine population-level effects, but they often ignore potential feedbacks associated with these various roles. 2. Here, we evaluate the effects of worker size distribution in bumblebee colonies on worker production in 24 observational colonies across three environments, using functional linear models. Functional linear models are an underused correlative technique that has been used to assess lag effects of environmental drivers on plant performance. We demonstrate potential applications of this technique for exploring high-dimensional ecological systems, such as the contributions of individuals with different traits to colony dynamics. 3. We found that more larger workers had mostly positive effects and more smaller workers had negative effects on worker production. Most of these effects were only detected under low or fluctuating resource environments suggesting that the advantage of colonies with larger-bodied workers becomes more apparent under stressful conditions. 4. We also demonstrate the wider ecological application of functional linear models. We highlight the advantages and limitations when considering these models, and how they are a valuable complement to many of these performance-based and manipulative experiments.

scholarly journals Molecular epidemiology of a fatal sarcoptic mange epidemic in endangered San Joaquin kit foxes (Vulpes macrotis mutica)

2020 ◽  
Author(s):  
Jaime L. Rudd ◽  
Deana L. Clifford ◽  
Brian L. Cypher ◽  
Joshua M. Hull ◽  
A. Jane Riner ◽  
...  
Keyword(s):  
Large Scale ◽  
Genetic Difference ◽  
Population Level ◽  
Sarcoptes Scabiei ◽  
Sarcoptic Mange ◽  
Canis Lupus Familiaris ◽  
Red Foxes ◽  
Kit Fox ◽  
Vulpes Macrotis ◽  
Vulpes Macrotis Mutica

Abstract Background: In 2013, sarcoptic mange, caused by Sarcoptes scabiei mites, precipitated a catastrophic decline of the formerly stable urban population of endangered San Joaquin kit foxes (Vulpes macrotis mutica) in Bakersfield, California, USA. In 2019, a smaller sarcoptic mange outbreak affected kit foxes 58 km southwest of Bakersfield in the town of Taft, California. To determine whether the Taft outbreak could have occurred as spillover from the Bakersfield outbreak and whether epidemic control efforts must involve not only kit foxes but also sympatric dogs (Canis lupus familiaris), coyotes (Canis latrans), and red foxes (Vulpes vulpes), we evaluated genotypes and gene flow among mites collected from each host species.Methods: We used 10 Sarcoptes microsatellite markers (SARM) to perform molecular typing of 445 S. scabiei mites collected from skin scrapings from twenty-two infested kit foxes, two dogs, five coyotes, and five red foxes from Bakersfield, Taft, and other nearby cities.Results: We identified 60 alleles across all SARM loci; kit fox- and red fox-derived mites were relatively monomorphic, while genetic variability was greatest in Bakersfield coyote- and dog-derived mites. AMOVA analysis documented distinct mite populations unique to hosts, with an overall FST of 0.467. The lowest FST (i.e. closest genetic relationship, FST = 0.038) was between Bakersfield and Taft kit fox-derived mites while the largest genetic difference was between Ventura coyote- and Taft kit fox-derived mites (FST = 0.843).Conclusion: These results confirm the close relationship between the Taft and Bakersfield outbreaks. Although a spillover event likely initiated the kit fox mange outbreak, mite transmission is now primarily kit fox-to-kit fox. Therefore, any large-scale population level intervention should focus on treating kit foxes within the city.

scholarly journals Conformity bias in the cultural transmission of music sampling traditions

2019 ◽  
Vol 6 (9) ◽  
pp. 191149 ◽  
Author(s):  
Mason Youngblood
Keyword(s):  
Cultural Transmission ◽  
Large Scale ◽  
Scale Up ◽  
Population Level ◽  
Neutral Evolution ◽  
Individual Level ◽  
Online Databases ◽  
Approximate Bayesian ◽  
Cultural Evolutionary ◽  
Turn Over

One of the fundamental questions of cultural evolutionary research is how individual-level processes scale up to generate population-level patterns. Previous studies in music have revealed that frequency-based bias (e.g. conformity and novelty) drives large-scale cultural diversity in different ways across domains and levels of analysis. Music sampling is an ideal research model for this process because samples are known to be culturally transmitted between collaborating artists, and sampling events are reliably documented in online databases. The aim of the current study was to determine whether frequency-based bias has played a role in the cultural transmission of music sampling traditions, using a longitudinal dataset of sampling events across three decades. Firstly, we assessed whether turn-over rates of popular samples differ from those expected under neutral evolution. Next, we used agent-based simulations in an approximate Bayesian computation framework to infer what level of frequency-based bias likely generated the observed data. Despite anecdotal evidence of novelty bias, we found that sampling patterns at the population-level are most consistent with conformity bias. We conclude with a discussion of how counter-dominance signalling may reconcile individual cases of novelty bias with population-level conformity.

scholarly journals Molecular epidemiology of a fatal sarcoptic mange epidemic in endangered San Joaquin kit foxes (Vulpes macrotis mutica)

2020 ◽  
Author(s):  
Jaime L. Rudd ◽  
Deana L. Clifford ◽  
Brian L. Cypher ◽  
Joshua M. Hull ◽  
A. Jane Riner ◽  
...  
Keyword(s):  
Large Scale ◽  
Genetic Difference ◽  
Population Level ◽  
Sarcoptes Scabiei ◽  
Sarcoptic Mange ◽  
Canis Lupus Familiaris ◽  
Red Foxes ◽  
Kit Fox ◽  
Vulpes Macrotis ◽  
Vulpes Macrotis Mutica

Abstract Background: In 2013, sarcoptic mange, caused by Sarcoptes scabiei mites, precipitated a catastrophic decline of the formerly stable urban population of endangered San Joaquin kit foxes (Vulpes macrotis mutica) in Bakersfield, California, USA. In 2019, a smaller sarcoptic mange outbreak affected kit foxes 58 km southwest of Bakersfield in the town of Taft, California. To determine whether the Taft outbreak could have occurred as spillover from the Bakersfield outbreak and whether epidemic control efforts must involve not only kit foxes but also sympatric dogs (Canis lupus familiaris), coyotes (Canis latrans), and red foxes (Vulpes vulpes), we evaluated genotypes and gene flow among mites collected from each host species. Methods: We used 10 Sarcoptes microsatellite markers (SARM) to perform molecular typing of 445 S. scabiei mites collected from skin scrapings from twenty-two infested kit foxes, two dogs, five coyotes, and five red foxes from Bakersfield, Taft, and other nearby cities. Results: We identified 60 alleles across all SARM loci; kit fox- and red fox-derived mites were relatively monomorphic, while genetic variability was greatest in Bakersfield coyote- and dog-derived mites. AMOVA analysis documented distinct mite populations unique to hosts, with an overall FST of 0.467. The lowest FST (i.e. closest genetic relationship, FST = 0.038) was between Bakersfield and Taft kit fox-derived mites while the largest genetic difference was between Ventura coyote- and Taft kit fox-derived mites (FST = 0.843). Conclusions: These results confirm the close relationship between the Taft and Bakersfield outbreaks. Although a spillover event likely initiated the kit fox mange outbreak, mite transmission is now primarily kit fox-to-kit fox. Therefore, any large-scale population level intervention should focus on treating kit foxes within the city.

scholarly journals Awareness, use and willingness to self-test for HIV: An analysis of cross-sectional population-based surveys in Malawi and Zimbabwe

2020 ◽  
Author(s):  
Cheryl Case Johnson ◽  
Melissa Neuman ◽  
Peter MacPherson ◽  
Augustine Choko ◽  
Caitlin Quinn ◽  
...  
Keyword(s):  
Sexual Risk ◽  
Large Scale ◽  
Scale Up ◽  
Population Level ◽  
Sociodemographic Factors ◽  
Population Based ◽  
African Countries ◽  
Cross Sectional ◽  
Self Test ◽  
Result Analysis

Abstract Background Many southern African countries are nearing the global goal to diagnose 90% of people with HIV by 2020. In 2016, 84% and 86% of people with HIV knew their status in Malawi and Zimbabwe respectively. Despite this progress, gaps remain, particularly among men (≥25 years). We investigated awareness, use and willingness to HIV self-test (HIVST) prior to large scale implementation and explored sociodemographic associations.Methods We pooled responses from two of the first cross-sectional Demographic Health Surveys to include HIVST questions: Malawi and Zimbabwe in 2015-16. Sociodemographic factors and sexual risk behaviours associated with never testing for HIV, and awareness, past use and future willingness to self-test were investigated using univariable and multivariable logistic regression, adjusting for the sample design and limiting analysis to participants with completed questionnaire and a valid HIV result. Analysis of willingness to self-test was restricted to Zimbabwean men as Malawians and women were not asked this question.Results Of 31 385 individuals, the proportion never-tested was higher for men (31.2%) than women (16.5%), p<0.001. For men, having ever tested increased with age. Past use and awareness of HIVST was very low, 1.2% and 12.6% respectively. Awareness was lower among women than men (9.1% vs 15.3%, adjusted odds ratio (aOR)=1.55; 95% confidence interval [CI]: 1.37-1.75), and at younger age, and lower education and literacy levels. Willingness to self-test among Zimbabwean men was high (84.5%), with having previously tested for HIV, high sexual risk, and being older (≥25 years) associated with greater willingness. Wealthy men had greater awareness of HIVST than poorer men (p<0.001). Men at higher sexual risk, compared to men at lower risk, had the greatest willingness to self-test (aOR=3.74; 95%CI: 1.39-10.03, p<0.009).Conclusions In 2015-16 many Malawian and Zimbabwean men had never tested for HIV. Despite low awareness and minimal HIVST experience at that time, willingness to self-test was high, especially in older men with moderate to high sexual risk. These data provide a valuable baseline against which to investigate population-level uptake of HIVST as programmes scale-up. Programmes introducing, or planning to introduce HIVST, should consider including questions in population-based surveys.

Dingoes affect activity of feral cats, but do not exclude them from the habitat of an endangered macropod

2012 ◽  
Vol 39 (7) ◽  
pp. 611 ◽  
Author(s):  
Yiwei Wang ◽  
Diana O. Fisher
Keyword(s):  
Camera Traps ◽  
Mesopredator Release ◽  
Negative Effects ◽  
Feral Cats ◽  
Terrestrial Predator ◽  
Negative Impacts ◽  
Time Of Year ◽  
A Site ◽  
Large Predators ◽  
Activity Times

Context The loss of large predators has been linked with the rise of smaller predators globally, with negative impacts on prey species (mesopredator release). Recent studies suggest that the dingo, Australia’s top terrestrial predator, inhibits predation on native mammals by the invasive red fox, and therefore reduces mammal extinctions. Feral cats also have negative effects on native mammals, but evidence that dingoes suppress cats remains equivocal. Aims We sought to examine whether dingoes might spatially or temporally suppress the activity of feral cats at a site containing the sole wild population of an endangered macropod subject to feral cat predation (the bridled nailtail wallaby). Methods We used camera traps to compare coarse and fine-scale spatial associations and overlaps in activity times of mammals between August 2009 and August 2010. Key results Dingoes and cats used the same areas, but there was evidence of higher segregation of activity times during wet months. Potential prey showed no spatial avoidance of dingoes. Peak activity times of dingoes and their major prey (the black-striped wallaby) were segregated during the wetter time of year (December to March). We did not find evidence that cats were spatially excluded from areas of high prey activity by dingoes, but there was low overlap in activity times between cats and bridled nailtail wallabies. Conclusions These findings support the contention that fear of dingoes can sometimes affect the timing of activity of feral cats. However, cats showed little spatial avoidance of dingoes at a coarse scale. Implications Control of dingoes should not be abandoned at the site, because the potential moderate benefits of reduced cat activity for this endangered and geographically restricted wallaby may not outweigh the detrimental effects of dingo predation.

scholarly journals Molecular epidemiology of a fatal sarcoptic mange epidemic in endangered San Joaquin kit foxes (Vulpes macrotis mutica)

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Jaime L. Rudd ◽  
Deana L. Clifford ◽  
Brian L. Cypher ◽  
Joshua M. Hull ◽  
A. Jane Riner ◽  
...  
Keyword(s):  
Large Scale ◽  
Genetic Difference ◽  
Population Level ◽  
Sarcoptes Scabiei ◽  
Sarcoptic Mange ◽  
Canis Lupus Familiaris ◽  
Red Foxes ◽  
Kit Fox ◽  
Vulpes Macrotis ◽  
Vulpes Macrotis Mutica

Abstract Background In 2013, sarcoptic mange, caused by Sarcoptes scabiei mites, precipitated a catastrophic decline of the formerly stable urban population of endangered San Joaquin kit foxes (Vulpes macrotis mutica) in Bakersfield, California, USA. In 2019, a smaller sarcoptic mange outbreak affected kit foxes 58 km southwest of Bakersfield in the town of Taft, California. To determine whether the Taft outbreak could have occurred as spillover from the Bakersfield outbreak and whether epidemic control efforts must involve not only kit foxes but also sympatric dogs (Canis lupus familiaris), coyotes (Canis latrans), and red foxes (Vulpes vulpes), we evaluated genotypes and gene flow among mites collected from each host species. Methods We used 10 Sarcoptes microsatellite markers (SARM) to perform molecular typing of 445 S. scabiei mites collected from skin scrapings from twenty-two infested kit foxes, two dogs, five coyotes, and five red foxes from Bakersfield, Taft, and other nearby cities. Results We identified 60 alleles across all SARM loci; kit fox- and red fox-derived mites were relatively monomorphic, while genetic variability was greatest in Bakersfield coyote- and dog-derived mites. AMOVA analysis documented distinct mite populations unique to hosts, with an overall FST of 0.467. The lowest FST (i.e. closest genetic relationship, FST = 0.038) was between Bakersfield and Taft kit fox-derived mites while the largest genetic difference was between Ventura coyote- and Taft kit fox-derived mites (FST = 0.843). Conclusions These results confirm the close relationship between the Taft and Bakersfield outbreaks. Although a spillover event likely initiated the kit fox mange outbreak, mite transmission is now primarily kit fox-to-kit fox. Therefore, any large-scale population level intervention should focus on treating kit foxes within the city.

СОЦИАЛЬНО-ЭКОНОМИЧЕСКИЕ КОНФЛИКТЫ В РАМКАХ «КАПИТАЛИЗМА ПЛАТФОРМ»

2019 ◽  
Vol 14 (3) ◽  
pp. 33
Author(s):  
L. V. Tomin
Keyword(s):  
Large Scale ◽  
Network Effects ◽  
Corporate Control ◽  
Balance Of Power ◽  
Negative Effects ◽  
Potential Threat ◽  
Communication Infrastructure ◽  
Political Effects ◽  
Information And Communication ◽  
Integrated Information

The article is devoted to the analysis of the structure, the peculiarities of functioning and the socio-economic and political effects of the «platform capitalism». The basis of this model is the network effects produced by the integrated information and communication infrastructure, which contribute to the monopolization and the constant expansion of platform companies into new areas. The principle of functioning of this infrastructure is the continuous collection and further monetization of data extracted from the interactions of individuals among themselves or with one of the elements of a digitalized economy or government structures. Such an infrastructure — forms a potential threat of strengthening state and corporate control over citizens. In addition, the activities of platform companies produce negative effects on the labor market, reinforcing the process of precarization of employment. The integrated information and communication infrastructure of platform companies form a system of a kind of «digital Taylorism», which deprives the employee of autonomy and privacy in the workplace. The influence of digitalization, subjected to the technocratic logic of the neoliberal model of governance in democratic countries, strengthens the de-politicization of relations between the citizen and the state and further changes the balance of power between labor and capital in favor of the latter. Large-scale protests of the last years against the companies of “capitalism of platforms” demonstrated the structural contradictions of this model and formed new forms of organization and actions of grassroots workers of the “digital economy”.

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