scholarly journals The relationship between propagule pressure and establishment success in alien bird populations: a re-analysis of Moulton & Cropper (2019)

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8766
Author(s):  
Tim M. Blackburn ◽  
Phillip Cassey ◽  
Julie L. Lockwood ◽  
Richard P. Duncan

A recent analysis by Moulton & Cropper (2019) of a global dataset on alien bird population introductions claims to find no evidence that establishment success is a function of the size of the founding population. Here, we re-analyse Moulton & Cropper’s data and show that this conclusion is based on flawed statistical methods—their data in fact confirm a strong positive relationship between founding population size and establishment success. We also refute several non-statistical arguments against the likelihood of such an effect presented by Moulton & Cropper. We conclude that a core tenet of population biology—that small populations are more prone to extinction—applies to alien populations beyond their native geographic range limits as much as to native populations within them.

2020 ◽  
Vol 2 (8) ◽  
pp. 101-110
Author(s):  
N. N. ILYSHEVA ◽  
◽  
E. V. KARANINA ◽  
G. P. LEDKOV ◽  
E. V. BALDESKU ◽  
...  

The article deals with the problem of achieving sustainable development. The purpose of this study is to reveal the relationship between the components of sustainable development, taking into account the involvement of indigenous peoples in nature conservation. Climate change makes achieving sustainable development more difficult. Indigenous peoples are the first to feel the effects of climate change and play an important role in the environmental monitoring of their places of residence. The natural environment is the basis of life for indigenous peoples, and biological resources are the main source of food security. In the future, the importance of bioresources will increase, which is why economic development cannot be considered independently. It is assumed that the components of resilience are interrelated and influence each other. To identify this relationship, a model for the correlation of sustainable development components was developed. The model is based on the methods of correlation analysis and allows to determine the tightness of the relationship between economic development and its ecological footprint in the face of climate change. The correlation model was tested on the statistical materials of state reports on the environmental situation in the Khanty-Mansiysk Autonomous Okrug – Yugra. The approbation revealed a strong positive relationship between two components of sustainable development of the region: economy and ecology.


2015 ◽  
Vol 43 (5) ◽  
pp. 757-766 ◽  
Author(s):  
Yueran Wen ◽  
Liu Liu

Based on a survey of 147 Chinese employees, we examined the relationship between perceived career plateau and turnover intention, and the moderating role of career anchor in challenge in this process. We hypothesized that perceived career plateau would be positively related to turnover intention, and that this relationship would be stronger in employees with a higher level of career anchor in challenge than in those with a lower level. The results showed that perceived career plateau had a strong positive relationship with turnover intention, especially in employees with a high level of career anchor in challenge. These findings have implications for research in career development and turnover intention, as well as in management practices.


2015 ◽  
Vol 42 (2) ◽  
pp. 185 ◽  
Author(s):  
Lise Ruffino ◽  
Diane Zarzoso-Lacoste ◽  
Eric Vidal

Bird conservation is nowadays a strong driving force for prioritising rodent eradications, but robust quantitative estimates of impacts are needed to ensure cost-effectiveness of management operations. Here, we review the published literature to investigate on what methodological basis rodent effects on island bird communities have been evaluated for the past six decades. We then discuss the advantages and limitations of each category of methods for the detection and quantification of impacts, and end with some recommendations on how to strengthen current approaches and extend our knowledge on the mechanisms of impacts. Impact studies (152 studies considered) emphasised seabirds (67%), black rats (63%) and the Pacific Ocean (57%). Among the most commonly used methods to study rodent impacts on birds were the observation of dead eggs or empty nests while monitoring bird breeding success, and the analyses of rodent diets, which can both lead to misleading conclusions if the data are not supported by direct field evidence of rodent predation. Direct observations of rodent–bird interactions (19% of studies) are still poorly considered despite their potential to reveal cryptic behaviours and shed light on the mechanisms of impacts. Rodent effects on birds were most often measured as a change or difference in bird breeding parameters (74% of studies), while estimates of bird population growth rates (4%) are lacking. Based on the outcomes of this literature review, we highlight the need for collecting unbiased population-level estimates of rodent impacts, which are essential prerequisites for predicting bird population growth scenarios and prioritising their conservation needs. This could be achieved by a more systematic integration of long-term monitoring of bird populations into rodent management operations and modelling bird population dynamics. We also strongly recommend including various complementary methods in impact assessment strategies to unravel complex interactions between rodents and birds and avoid faulty evidence. Finally, more research should be devoted to a better understanding of the cases of non-impacts (i.e. long-term coexistence) and those impacts mediated by mechanisms other than predation and ecosystem-level processes.


2021 ◽  
Vol 10 (1) ◽  
pp. 117
Author(s):  
Wanda Tri Utami ◽  
Ali Mustadi ◽  
Marsigit Marsigit ◽  
Ibrahim Ibrahim

The writing of this article is a survey research with the aim of knowing the relationship between mathematical disposition and self-efficacy of PGSD/ PGMI students in universities throughout Indonesia. This study used a total of 37 public and private universities with 357 students using questionnaire data collection techniques. The data obtained were analyzed using quantitative descriptive. In addition, data analysis used Spearman's Rho. The results explained that the mathematical disposition with self-efficacy of PGSD / PGMI students in Indonesia based on the average questionnaire filling reached a correlation coefficient of 0.612 which was included in the very strong category. Sig. Value (2-tailed) obtained 0,000 which is smaller than 0.01 which means that there is a significant relationship between mathematical disposition variables and self-efficacy. This caused a strong positive relationship between mathematical disposition and student self-efficacy. AbstrakPenulisan artikel ini merupakan penelitian survei dengan tujuan mengetahui hubungan disposisi matematis dan self-efficacy mahasiswa PGSD/PGMI yang berada di Universitas se-Indonesia. Penelitian ini menggunakan subjek yang berjumlah 37 universitas negeri dan swasta dengan 357 mahasiswa dengan tekhnik pengumpulan data penyebaran angket. Data yang diperoleh dianalisis menggunakan deskriptif kuantitatif. Selain itu, analisis data menggunakan Spearman’s Rho. Hasil penelitian menjelaskan bahwa disposisi matematis dengan self-efficacy mahasiswa PGSD/PGMI yang berada di Indonesia berdasarkan rata-rata pengisian angket mencapai koefisien korelasi 0.612 yang termasuk dalam kategori sangat kuat. Nilai Sig. (2-tailed) didapat 0.000 yang lebih kecil dari 0.01 yang memiliki makna bahwa terdapat hubungan signifikan antara variabel disposisi matematis dengan self-efficacy. Hal tersebut menyebabkan hubungan positif yang kuat antara disposisi matematis dengan self-efficacy mahasiswa. 


Author(s):  
Ali Giginyu ◽  
Danladi Bala

The study was conducted to determine the attitude of extension staff towards agricultural extension work, examine the nature of the relationship between farmers and agricultural extension staff, examine the scope of farmers’ satisfaction with services provided by extension workers, and determine the challenges affecting effective relationship between farmers and agricultural extension staff in Kura Local Government, Kano State, Nigeria. The population of the study was 2567 registered farmers and 8 qualified Extension workers. Questionnaire was used as an instrument for data collection. 80 respondents were used as the sampling frame. The data were analyzed using descriptive statistics i.e. percentage and frequency count. The research findings revealed that there is strong positive relationship between behavior of Agricultural Extension Workers and farmers satisfaction, the findings of the study indicated, among others, that the challenges affecting relationship between the farmers and the Extension Staff in the study area included staff inadequacy, slow process and the attitude of the Extension Workers toward Agricultural Extension exercise included dedication to duty, positive manners, among the others. Additionally, the findings indicated that the nature of the relationship between the farmers and Agricultural Extension Workers was based on Extension workers farm visit, response to request and enquiries by the farmers and friendliness to the farmers. It is therefore, recommended that the number of Extension workers should be added and welfare package of the Extension Workers should be improved to avoid delay in the process, to mention but a few.


2012 ◽  
Vol 524-527 ◽  
pp. 2388-2393 ◽  
Author(s):  
Nan Wang ◽  
Mahjoub Elnimeiri

The phenomenon of climate change is becoming a global problem. One of the most important reasons of climate change is the increase in CO2 levels due to emissions from fossil fuel energy use in daily human activities. This research will use the data of the annual average temperature and energy consumption in the past 41 years of Shanghai, the largest city in China, to establish the statistical relationship between climate change and energy consumption. It is found that there is a strong positive relationship between climate change and energy consumption in Shanghai. The phenomenon of climate change could be controlled by reducing excessive energy consumption in people’s daily life. Furthermore, this paper will also discuss the reason of such relationship, and provide suggesstions of saving energy and protecting our environment.


2003 ◽  
Vol 40 (5) ◽  
pp. 481-485 ◽  
Author(s):  
J. D. Clark ◽  
P. A. Mossey ◽  
L. Sharp ◽  
J. Little

Objective The purpose of this study was to investigate the association between socioeconomic status and orofacial clefts (OFC) in Scotland. Design Study of prevalence at birth over a 10-year period using an area-based measure of material deprivation. Setting Population-based study throughout Scotland. Participants Eight hundred thirty-four live births with OFC born between January 1, 1989, and December 31, 1998, ascertained from the nationwide register of the Cleft Service in Scotland, compared with the total 603,825 live births in Scotland in this period. Results There was a strong positive relationship whereby the prevalence of OFC at birth increased with increasing deprivation. This trend was statistically significant for cleft lip and/or palate (CL[P]: p = .016) but not for cleft palate (CP; p = .078). For each type of cleft, the relative risk among those resident in the most deprived areas, compared with those resident in the least deprived areas, was 2.33. Conclusions The association between OFC and socioeconomic status is consistent with a report for an earlier period in a smaller part of Scotland. Unlike the earlier study, this pattern appears to be stronger for CL(P) than for CP. These observations do not appear to be an artifact of recording. It is possible that they reflect the association between deprivation and risk factors for OFC, most likely tobacco smoking during pregnancy. Because the relationship between OFC and socioeconomic status appears to have been virtually unstudied in other populations, it would be valuable to investigate this relationship elsewhere and determine whether known risk factors account for the relationship.


Parasitology ◽  
1995 ◽  
Vol 111 (S1) ◽  
pp. S135-S151 ◽  
Author(s):  
B. T. Grenfell ◽  
K. Wilson ◽  
V. S. Isham ◽  
H. E. G. Boyd ◽  
K. Dietz

SUMMARYThe characteristically aggregated frequency distribution of macroparasites in their hosts is a key feature of host–parasite population biology. We begin with a brief review of the theoretical literature concerning parasite aggregation. Though this work has illustrated much about both the sources and impact of parasite aggregation, there is still no definitive analysis of both these aspects. We then go on to illustrate the use of one approach to this problem – the construction of Moment Closure Equations (MCEs), which can be used to represent both the mean and second moments (variances and covariances) of the distribution of different parasite stages and phenomenological measures of host immunity. We apply these models to one of the best documented interactions involving free-living animal hosts – the interaction between trichostrongylid nematodes and ruminants. The analysis compares patterns of variability in experimental infections of Teladorsagia circumcincta in sheep with the equivalent wildlife situation – the epidemiology of T. circumcincta in a feral population of Soay sheep on St Kilda, Outer Hebrides. We focus on the relationship between mean parasite load and aggregation (inversely measured by the negative binomial parameter, k) for cohorts of hosts. The analysis and empirical data indicate that k tracks the increase and subsequent decline in the mean burden with host age. We discuss this result in terms of the degree of heterogeneity in the impact of host immunity or parasite-induced mortality required to shorten the tail of the parasite distribution (and therefore increase k) in older animals. The model is also used to analyse the relationship between estimated worm and egg counts (since only the latter are often available for wildlife hosts). Finally, we use these results to review directions for future work on the nature and impact of parasite aggregation.


Euphytica ◽  
2006 ◽  
Vol 148 (1-2) ◽  
pp. 87-96 ◽  
Author(s):  
M. Alejandra Martínez-Ghersa ◽  
Claudio M. Ghersa

2011 ◽  
Vol 56 (4) ◽  
pp. 622-641 ◽  
Author(s):  
Victoria L. Brescoll

Although past research has noted the importance of both power and gender for understanding volubility—the total amount of time spent talking—in organizations, to date, identifying the unique contributions of power and gender to volubility has been somewhat elusive. Using both naturalistic data sets and experiments, the present studies indicate that while power has a strong, positive effect on volubility for men, no such effect exists for women. Study 1 uses archival data to examine the relationship between the relative power of United States senators and their talking behavior on the Senate floor. Results indicate a strong positive relationship between power and volubility for male senators, but a non-significant relationship for female senators. Study 2 replicates this effect in an experimental setting by priming the concept of power and shows that though men primed with power talk more, women show no effect of power on volubility. Mediation analyses indicate that this difference is explained by women’s concern that being highly voluble will result in negative consequences (i.e., backlash). Study 3 shows that powerful women are in fact correct in assuming that they will incur backlash as a result of talking more than others—an effect that is observed among both male and female perceivers. Implications for the literatures on volubility, power, and previous studies of backlash are discussed.


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