scholarly journals Time since first record and population density influence range sizes of non-native plants, but also of native plants, in a chronically overgrazed island

2021 ◽  
Vol 154 (2) ◽  
pp. 173-182
Author(s):  
Pedro P. Garcillán ◽  
Carlos Martorell
Keyword(s):  
Population Density ◽  
Residence Time ◽  
Native Species ◽  
Native Plants ◽  
Range Size ◽  
Time Range ◽  
Mexican Pacific ◽  
Size Relationship ◽  
Relationship Of ◽  
The Relationship

Background and aims − Humans are increasingly introducing species to new regions. It is necessary to understand the processes that drive the expansion of non-native species into these new habitats across multiple spatiotemporal scales.Material and methods − We studied the spatial distribution of the non-native flora (39 species) of Guadalupe Island (246 km2) in the Mexican Pacific. We analyzed how residence time (time since first report in historical sources, 1875–2004) and species attributes (population density, flowering phenology, and individual height) are related with range sizes of non-native plants. To test whether the residence time – range size relationship of non-native plants can result from other factors besides time since their arrival, we compared it to the residence time – range size relationship of native plants. Range sizes were obtained using herbarium data and a systematic field sampling of 110 transects (50 × 2 m) throughout the entire island. We used beta regression to analyze the relationship of range sizes with residence time and species attributes.Key results − Range sizes of non-natives showed a positive relationship with residence time, flower phenology, and notably with plant density, but not with individual height. However, similar relationships were found for native species, casting doubts on whether our results reflect the range expansion rates of non-native species. Conclusions − Our results suggest that the production of large numbers of propagules, both as a result of long reproductive periods and large population sizes, determines to a large extent the rates of range size expansion of non-native species. However, the relationship we found between time since discovery and range size may arise from sampling biases, biological processes, or – most likely – both. This highlights the need for new approaches that allow us to discern the relative contributions of bias and process in our study of non-native species expansion.

scholarly journals Alien Species vs. Native Species: From Community Ecology to Eco-Evolutionary Dynamics

2019 ◽  
Author(s):  
Andersonn Silveira Prestes
Keyword(s):  
Alien Species ◽  
Exotic Species ◽  
Native Species ◽  
Evolutionary Dynamics ◽  
Evolutionary Processes ◽  
Native Communities ◽  
Individualized Approach ◽  
History Of ◽  
Relationship Of ◽  
The Relationship

The establishment and spread of exotic species is a contemporary major concern. Alien species may become invasive in their new habitat, leading to both/either environmental and/or economic impacts. I briefly reviewed the literature in the last decade about the relationship of exotic species and native communities. I identified that professionals usually approach the subject in two main points of view: (1) researchers tend to point out the impacts of alien species on entire communities, evaluating if the relationship is positive, negative or neutral; (2) they focus on the eco-evolutionary processes involved in the introductions, the dynamics of invasion, and individual study cases. When evaluating the response of introductions to entire communities, evidence seems to be ambiguous and may support positive, negative or neutral relationship, especially depending on the scale approached. The unique eco-evolutionary pathways of each introduction may be a great shortcoming in the searching for generalities. On the other hand, advances have been made in understanding the dynamics of invasion on different lineages through a more selective/individualized approach. I suggest that the dynamics of invasion might be studied through a perspective in which different eco-evolutionary processes, levels of organization (from gene to entire communities), the history of the organism(s) and time are taken into account. Individual cases might be compared in attempt to understand how the relationship exotic and native works and in the search for generalities.

scholarly journals Referential Chains Reveal Predictive Processes and Form-to-Function Mapping: An Electroencephalographic Study Using Naturalistic Story Stimuli

2021 ◽  
Vol 12 ◽  
Author(s):  
Ingmar Brilmayer ◽  
Petra B. Schumacher
Keyword(s):  
Language Comprehension ◽  
Cognitive Status ◽  
Event Related Potential ◽  
Time Range ◽  
Double Function ◽  
Referential Expressions ◽  
Predictive Processes ◽  
Relationship Of ◽  
The Relationship ◽  
Function Mapping

In discourse pragmatics, different referential forms are claimed to be indicative of the cognitive status of a referent in the current discourse. Referential expressions thereby possess a double function: They point back to an (existing) referent (form-to-function mapping), and they are used to derive predictions about a referent’s subsequent recurrence in discourse. Existing event-related potential (ERP) research has mainly focused on the form-to-function mapping of referential expression. In the present ERP study, we explore the relationship of form-to-function mapping and prediction derived from the antecedent of referential expressions in naturalistic auditory language comprehension. Specifically, the study investigates the relationship between the form of a referential expression (pronoun vs. noun) and the form of its antecedent (pronoun vs. noun); i.e., it examines the influence of the interplay of predictions derived from an antecedent (forward-looking function) and the form-to-function mapping of an anaphor (backward-looking function) on the ERPs time-locked to anaphoric expressions. The results in the time range of the P300 and N400 allow for a dissociation of these two functions during online language comprehension.

scholarly journals Relationships of total COVID-19 cases and deaths with ten demographic, economic and social indicators

2020 ◽  
Author(s):  
Dimitar Valev
Keyword(s):  
Population Density ◽  
Statistical Significance ◽  
Social Indicators ◽  
Composite Index ◽  
Correlation Coefficients ◽  
Statistical Relationships ◽  
Student’S T ◽  
Relationship Of ◽  
The Relationship ◽  
Economic And Social Indicators

AbstractThe statistical relationships of total COVID-19 Cases and Deaths per million populations in 45 countries, where 85.8% of the world’s population lives with 10 demographic, economic and social indicators were studied. Data for 28 May 2020 were used in the main calculations. The relationship of Deaths per million population and total Cases per million population is very close and reaches correlation coefficient R = 0.926. It is interesting that the close correlations were found of Cases and Deaths per 1 million with a purely economic index like GDP PPP per capita, where R = 0.687 and R = 0.660, respectively. Even more close correlations were found of Cases and Deaths per 1 million with a composite index HDI, where the correlation coefficients reach 0.724 and 0.680, respectively. The main reason for these paradoxical results is the underestimation of pandemic restrictions in the form of masks, social distance and disinfection in most of these countries. Other indicators (excluding Gini index and Population Density) also show statistically significant correlations with Cases and Deaths per 1 million with correlation coefficients from 0.432 to 0.634. The statistical significance of the found correlations determined using Student’s t-test was p <0.0001. Surprisingly, there was no statistically significant correlation between Cases and Deaths with Population Density. To check whether there is a change in the correlations with the development of the pandemic, a statistical analysis was made for four different dates – 9 April, 28 May, 7 August and 30 November 2020. It was found that the correlation coefficients of COVID-19 cases and Deaths with the rest indicators decrease during the pandemic.

Endemicity and land‐use type influence the abundance–range‐size relationship of birds on a tropical island

2020 ◽  
Author(s):  
Rachakonda Sreekar ◽  
Katerina Sam ◽  
Salindra K. Dayananda ◽  
Uromi Manage Goodale ◽  
Sarath W. Kotagama ◽  
...  
Keyword(s):  
Land Use ◽  
Range Size ◽  
Land Use Type ◽  
Tropical Island ◽  
Size Relationship ◽  
Relationship Of
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