Role of propagule pressure in colonization success: disentangling the relative importance of demographic, genetic and habitat effects

ABSTRACTPredicting whether individuals will colonize a novel habitat is of fundamental ecological interest and is crucial to both conservation efforts and invasive species management. A consistently supported predictor of colonization success is the number of individuals introduced, also called propagule pressure. Propagule pressure increases with the number of introductions and the number of individuals per introduction (the size of the introduction), but it is unresolved which process is a stronger driver of colonization success. Furthermore their relative importance may depend upon the environment, with multiple introductions potentially enhancing colonization of fluctuating environments. To evaluate the relative importance of the number and size of introductions and its dependence upon environmental variability, we paired demographic simulations with a microcosm experiment. Using Tribolium flour beetles as a model system, we introduced a fixed number of individuals into replicated novel habitats of stable or fluctuating quality, varying the number of introductions through time and size of each introduction. We evaluated establishment probability and the size of extant populations after 7 generations. In the simulations and microcosms, we found that establishment probability increased with more, smaller introductions, but was not affected by biologically realistic fluctuations in environmental quality. Population size was not significantly affected by environmental variability in the simulations, but populations in the microcosms grew larger in a stable environment, especially with more introduction events. In general, the microcosm experiment yielded higher establishment probability and larger populations than the demographic simulations. We suggest that genetic mechanisms likely underlie these differences and thus deserve more attention in efforts to parse propagule pressure. Our results highlight the importance of preventing further introductions of undesirable species to invaded sites, and suggest conservation efforts should focus on increasing the number of introductions or re-introductions of desirable species rather than increasing the size of those introduction events.

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Population Control (Review Article)

The Pakistan Development Review ◽

10.30541/v1i3pp.89-98 ◽

1961 ◽

Vol 1 (3) ◽

pp. 89-98

Author(s):

Karol J. Krotki

Keyword(s):

Population Control ◽

Review Article ◽

Small Enterprise ◽

Opportunity Costs ◽

Relative Importance ◽

Factual Information ◽

Undue Influence ◽

Clear Cut ◽

Economic Considerations

Discussions about the role of small enterprise in economic development tend to remain inconclusive partly because of the difficulty of assessing the relative importance of economic and non-economic objectives and partly because of the dearth of factual information on which to base an economic calculus. It is probably true, moreover, that, because of a lack of general agreement as to the economic case for or against small enterprise, non-economic considerations, including some merely romantic attitudes toward smallness and bigness, tend to exert an undue influence on public policies. There may, of course, be no clear-cut economic case. And noneconomic considerations should and will inevitably weigh significantly in policy decisions. If, however, some of the economic questions could be settled by more and better knowledge, these decisions could more accurately reflect the opportunity costs of pursuing non-economic objectives.

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The Arctic as a “Strategic” and “Important” Chinese Foreign Policy Interest: Exploring the Role of Labels and Hierarchies in China’s Arctic Discourses

Journal of Current Chinese Affairs ◽

10.1177/18681026211018699 ◽

2021 ◽

pp. 186810262110186

Author(s):

Patrik Andersson

Keyword(s):

Foreign Policy ◽

International Relations ◽

Political Discourse ◽

Chinese Foreign Policy ◽

The Arctic ◽

Relative Importance ◽

Precise Understanding ◽

New Frontier ◽

Political Priority

Research confirms that China is becoming more engaged in the Arctic. However, international relations scholarship often extrapolates from relatively few instances of activity to wide-ranging claims about Chinese priorities. Fortunately, Chinese political discourse is organised by labels that allow us to study how the Arctic is classified and ranked along China’s other foreign policy priorities. This article analyses two such classifications – “important maritime interest” and “strategic new frontier,” exploring how they have come about, what they mean, and how they add political priority to the Arctic. It argues that hierarchies are constructed in two ways: by adding gradients and by including/excluding categories of priority. It views categories as performative: they not only convey information about character and relative importance of interests but are also used for achieving different objectives. By focusing on foreign policy classifications, the article contributes to a more nuanced and precise understanding of China’s Arctic interests.

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Study of the role of Chlamydia, Mycoplasma, Ureaplasma and other microaerophilic and aerobic bacteria in uterine infections of mares with reproductive disorders

Acta Veterinaria Hungarica ◽

10.1556/avet.51.2003.1.4 ◽

2003 ◽

Vol 51 (1) ◽

pp. 45-52 ◽

Cited By ~ 5

Author(s):

László Szeredi ◽

M. Tenk ◽

I. Schiller ◽

Keyword(s):

Pathogenic Bacteria ◽

Anaerobic Bacteria ◽

Aerobic Bacteria ◽

Relative Importance ◽

Reproductive Disorders ◽

Taylorella Equigenitalis

In six healthy mares and 24 mares showing reproductive disorders swab samples were taken from the fossa clitoridis to isolate Taylorella equigenitalis, and from the uterus to isolate mycoplasmas, ureaplasmas and other aerobic bacteria. Swab samples were also taken from the uterus for Chlamydiaantigen ELISA and ChlamydiaPCR studies. The uterus of 27 mares was examined cytologically, and biopsy samples were taken from the endometrium for histological examinations and for immunohistochemical examinations aimed at the detection of chlamydiae. T. equigenitalis, mycoplasmas, ureaplasmas and chlamydiae could not be detected from any of the mares examined. Aerobic facultative pathogenic bacteria were isolated from mares with endometritis in four cases. In 18 out of 22 mares with endometritis (82%) no infective agents could be demonstrated. Further studies are needed to elucidate the relative importance of non-infectious causes of endometritis and of anaerobic bacteria often detectable in the uterus in the aetiology of the reproductive disorders observed.

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Do patients value a hospital’s innovativeness reputation? A multi-method approach to assess the relative importance of innovativeness reputation in patients’ hospital choice

Health Services Management Research ◽

10.1177/0951484817748157 ◽

2017 ◽

Vol 31 (3) ◽

pp. 138-153 ◽

Cited By ~ 1

Author(s):

Sebastian Gurtner ◽

Nadine Hietschold ◽

María Vaquero Martín

Keyword(s):

Value Added ◽

Patient Choice ◽

Relative Importance ◽

Hospital Choice ◽

Patient Decision ◽

Technical Innovations ◽

Multi Method Approach ◽

Method Approach

Innovations in health care are costly and risky, but they also provide the opportunity for hospitals to increase quality of care, to distinguish themselves from competitors and to attract patients. While numerous hospitals strive to increase their innovativeness by adopting a costly innovation leader strategy, the question of whether this actually influences the patient’s choice remains unanswered. To understand the role of innovativeness from the patient perspective, this study conceptualizes the construct of innovativeness reputation of hospitals and determines its relevance in patients’ hospital choice decisions. In the pretest, we identified six dimensions of innovativeness reputation such as progressive work procedures and value added services. We then used three different quantitative multi-criteria decision-making methods to evaluate the relative importance of innovativeness reputation in patient choice. We collected data from 355 former German patients who had undergone elective non-emergency surgery. Overall, innovativeness reputation accounts for 11.6%–16.8% of the patient decision. Innovativeness reputation has a moderate influence on hospital choice and should be taken into account by managers. Since technical innovations are costly, hospitals should use other means to enhance their innovative image. Strategies such as emphasizing value added services can enable hospitals to increase their innovativeness reputation efficiently.

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A Gnotobiotic Model to Examine Plant and Microbiome Contributions to Survival under Arsenic Stress

Microorganisms ◽

10.3390/microorganisms9010045 ◽

2020 ◽

Vol 9 (1) ◽

pp. 45

Author(s):

María del Carmen Molina ◽

James F. White ◽

Sara García-Salgado ◽

M. Ángeles Quijano ◽

Natalia González-Benítez

Keyword(s):

Seedling Growth ◽

Endophytic Bacteria ◽

Root Hairs ◽

Resistant Bacteria ◽

Relative Importance ◽

Early Stages ◽

Bacterial Interaction ◽

Arsenic Stress ◽

Free Media

So far, the relative importance of the plant and its microbiome in the development of early stages of plant seedling growth under arsenic stress has not been studied. To test the role of endophytic bacteria in increasing plant success under arsenic stress, gnotobiotic seeds of J. montana were inoculated with two endophytic bacteria: Pantoea conspicua MC-K1 (PGPB and As resistant bacteria) and Arthrobacter sp. MC-D3A (non-helper and non-As resistant bacteria) and an endobacteria mixture. In holobiotic seedlings (with seed-vectored microbes intact), neither the capacity of germination nor development of roots and lateral hairs was affected at 125 μM As(V). However, in gnotobiotic seedlings, the plants are negatively impacted by absence of a microbiome and presence of arsenic, resulting in reduced growth of roots and root hairs. The inoculation of a single PGPB (P. conspicua-MCK1) shows a tendency to the recovery of the plant, both in arsenic enriched and arsenic-free media, while the inoculation with Arthrobacter sp. does not help in the recovery of the plants. Inoculation with a bacterial mixture allows recovery of plants in arsenic free media; however, plants did not recover under arsenic stress, probably because of a bacterial interaction in the mixture.

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Subdimensions of total rewards satisfaction and creativity among R&D employees: a moderated mediation model

Personnel Review ◽

10.1108/pr-12-2019-0656 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Zhenyuan Wang ◽

Jianghong Du ◽

Herman H.M. Tse ◽

Jun Gu ◽

Hui Meng ◽

...

Keyword(s):

Work Stress ◽

Work Engagement ◽

Indirect Effects ◽

Moderated Mediation ◽

Relative Importance ◽

Mediation Model ◽

Content Type ◽

Moderated Mediation Model ◽

Total Rewards

PurposeThis study aims to explore the relative importance of the subdimensions of total rewards satisfaction in predicting research and development (R&D) employee creativity. In addition, the study examines the indirect effects of the subdimensions of total rewards satisfaction on creativity via work engagement and the moderating role of challenge-related work stress in the first stage.Design/methodology/approachA two-wave design was used, in which total rewards satisfaction and challenge-related work stress were measured in the first wave. Work engagement and creativity were measured in the second wave. Dominance analysis and the latent moderated mediation model were used for the data analyses.FindingsThe analyses show that nonfinancial rewards satisfaction completely dominates indirect and direct financial rewards satisfaction when predicting creativity. Indirect financial rewards satisfaction completely dominates direct financial rewards satisfaction when predicting creativity. Work engagement mediates the relationships between the subdimensions of total rewards satisfaction and creativity. Challenge-related work stress moderates the relationships between the subdimensions of total rewards satisfaction and work engagement and the indirect effects of the subdimensions of total rewards satisfaction on creativity via work engagement.Practical implicationsThe results imply that managers should set challenge demands for R&D employees and try to improve their total rewards satisfaction, especially their nonfinancial and indirect financial rewards satisfaction, for them to be more creative.Originality/valueThis empirical study contributes to the literature by comparing the relative importance of the different dimensions of total rewards satisfaction in predicting creativity. The study also clarifies how (through work engagement) and when (based on challenge-related work stress) the subdimensions of total rewards satisfaction are positively related to R&D employees' creativity.

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Effects of micro-, meio- and macroinvertebrates associated with burial on the decomposition of an aquatic macrophyte (Vallisneria natans) in a eutrophic shallow lake in China

Marine and Freshwater Research ◽

10.1071/mf18148 ◽

2019 ◽

Vol 70 (4) ◽

pp. 554

Author(s):

Shaojun Chen ◽

Dong Wang

Keyword(s):

Aquatic Invertebrates ◽

Microbial Respiration ◽

Aquatic Macrophyte ◽

Mesh Size ◽

Relative Importance ◽

Vallisneria Natans ◽

Plant Decomposition ◽

Invertebrate Abundance ◽

Average Contribution

Aquatic invertebrates play an important role in plant decomposition. However, little information is available regarding the relative importance of micro-, meio- and macroinvertebrates in this process, particularly their role in the decomposition of buried organic matter. To investigate the role of these invertebrates in the decomposition of the aquatic macrophyte Vallisneria natans, leaves of V. natans were placed in litterbags with four different mesh sizes (0.025, 0.042, 0.5 and 5mm) and the bags were either incubated at the sediment–water (SW) interface or buried at a depth of 10cm (B10) for 60 days in Lake Nanhu, China, in July 2015. Increased mesh size significantly increased the loss of plant mass. The decomposition rate ranged from 0.0173 to 0.0467day–1 in the SW treatment, and from 0.0083 to 0.0280day–1 in the B10 treatment. Excluding microinvertebrates, burial significantly affected microbial respiration and invertebrate abundance. Increased mesh size increased invertebrate abundance and richness, but did not significantly affect microbial respiration in either treatment. The average contribution of micro-, meio- and macroinvertebrates and microbes to plant mass loss in the SW treatment was 23.1, 13.5, 7.0 and 56.5% respectively, compared with 19.7, 24.5, 12.3 and 43.5% respectively in the B10 treatment. The results of this study reveal the important but underestimated role of micro- and meioinvertebrates in macrophyte decomposition.

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