scholarly journals Quantifying microbially mediated fitness differences reveals the tendency for plant-soil feedbacks to drive species exclusion among California annual plants

2020 ◽  
Author(s):  
Gaurav S. Kandlikar ◽  
Xinyi Yan ◽  
Jonathan M. Levine ◽  
Nathan J.B. Kraft
Keyword(s):  
Soil Microbes ◽  
Empirical Studies ◽  
Annual Plants ◽  
Plant Population Dynamics ◽  
Plant Interactions ◽  
Frequency Dependent ◽  
Plant Soil ◽  
The Impact ◽  
Plant Coexistence ◽  
Average Fitness

AbstractSoil microorganisms influence a variety of processes in plant communities. Many the-oretical and empirical studies have shown that dynamic feedbacks between plants and soil microbes can stabilize plant coexistence by generating negative frequency-dependent plant population dynamics. However, inferring the net effects of soil microbes on plant coexistence requires also quantifying the degree to which they provide one species an average fitness advantage, an effect that has received little empirical attention. We conducted a greenhouse study to quantify microbially mediated stabilization and fitness differences among fifteen pairs of annual plants that co-occur in southern California grasslands. We found that although soil microbes frequently generate negative frequency-dependent dynamics that stabilize plant interactions, they simultaneously mediate large average fitness differences between species. The net result is that if the plant species are otherwise competitively equivalent, the impact of plant-soil feedbacks is often to favor species exclusion over coexistence, a result that only becomes evident by quantifying the microbially mediated fitness difference. Our work highlights that comparing the stabilizing effects of plant-soil feedbacks to the fitness difference they generate is essential for understanding the influence of soil microbes on plant diversity.

scholarly journals Intraspecific genetic variation and species coexistence in plant communities

2016 ◽  
Vol 12 (1) ◽  
pp. 20150853 ◽  
Author(s):  
Bodil K. Ehlers ◽  
Christian F. Damgaard ◽  
Fabien Laroche
Keyword(s):  
Genetic Variation ◽  
Species Interactions ◽  
Species Coexistence ◽  
Empirical Studies ◽  
Genotype Distribution ◽  
Plant Interactions ◽  
Intraspecific Genetic Variation ◽  
The Impact ◽  
Plant Coexistence ◽  
Plant Plant

Many studies report that intraspecific genetic variation in plants can affect community composition and coexistence. However, less is known about which traits are responsible and the mechanisms by which variation in these traits affect the associated community. Focusing on plant–plant interactions, we review empirical studies exemplifying how intraspecific genetic variation in functional traits impacts plant coexistence. Intraspecific variation in chemical and architectural traits promotes species coexistence, by both increasing habitat heterogeneity and altering competitive hierarchies. Decomposing species interactions into interactions between genotypes shows that genotype × genotype interactions are often intransitive. The outcome of plant–plant interactions varies with local adaptation to the environment and with dominant neighbour genotypes, and some plants can recognize the genetic identity of neighbour plants if they have a common history of coexistence. Taken together, this reveals a very dynamic nature of coexistence. We outline how more traits mediating plant–plant interactions may be identified, and how future studies could use population genetic surveys of genotype distribution in nature and methods from trait-based ecology to better quantify the impact of intraspecific genetic variation on plant coexistence.

scholarly journals A quantitative synthesis of soil microbial effects on plant species coexistence

2021 ◽  
Author(s):  
Xinyi Yan ◽  
Jonathan M. Levine ◽  
Gaurav S. Kandlikar
Keyword(s):  
Species Interactions ◽  
Soil Microbes ◽  
Species Coexistence ◽  
Meta Analysis ◽  
Priority Effects ◽  
Soil Microbial ◽  
Plant Soil ◽  
Niche Differences ◽  
Plant Coexistence ◽  
Microbial Effects

Soil microorganisms play a major role in shaping plant diversity, not only through their direct effects as pathogens, mutualists, and decomposers, but also by altering interactions between plants. In particular, previous research has shown that the soil community often generates frequency-dependent feedback loops among plants that can either destabilize species interactions, or generate stabilizing niche differences that promote species coexistence. However, recent insights from modern coexistence theory have shown that microbial effects on plant coexistence depend not only on these stabilizing or destabilizing effects, but also on the degree to which they generate competitive fitness differences. While many previous experiments have generated the data necessary for evaluating microbially mediated fitness differences, these effects have rarely been quantified in the literature. Here we present a meta-analysis of data from 50 studies, which we used to quantify the microbially mediated (de)stabilization and fitness differences derived from a classic plant-soil feedback model. Across 518 pairwise comparisons, we found that soil microbes generated both stabilization (or destabilization) and fitness differences, but also that the microbially mediated fitness differences dominated. As a consequence, if plants are otherwise equivalent competitors, the balance of soil microbe-generated (de)stabilization and fitness differences drives species exclusion much more frequently than coexistence or priority effects. Our work shows that microbially mediated fitness differences are an important but overlooked effect of soil microbes on plant coexistence. This finding paves the way for a more complete understanding of the processes that maintain plant biodiversity.

Dampak Kebijakan Moneter Pada Output Di Negara-Negara ASEAN Tahun 1980-2014

2017 ◽  
Vol 4 (1) ◽  
pp. 58-70
Author(s):  
Nur Widiastuti
Keyword(s):  
Monetary Policy ◽  
Interest Rate ◽  
Fixed Effects ◽  
Empirical Studies ◽  
Negative Relationship ◽  
Least Square ◽  
Fixed Effects Model ◽  
State Data ◽  
Ordinary Least Square ◽  
The Impact

The Impact of monetary Policy on Ouput is an ambiguous. The results of previous empirical studies indicate that the impact can be a positive or negative relationship. The purpose of this study is to investigate the impact of monetary policy on Output more detail. The variables to estimatate monetery poicy are used state and board interest rate andrate. This research is conducted by Ordinary Least Square or Instrumental Variabel, method for 5 countries ASEAN. The state data are estimated for the period of 1980 – 2014. Based on the results, it can be concluded that the impact of monetary policy on Output shown are varied.Keyword: Monetary Policy, Output, Panel Data, Fixed Effects Model

Designing a creative programming unit within the elementary school core curriculum

2020 ◽  
Author(s):  
Yumiko Murai ◽  
Ryohei Ikejiri ◽  
Yuhei Yamauchi ◽  
Ai Tanaka ◽  
Seiko Nakano
Keyword(s):  
Core Curriculum ◽  
Design Research ◽  
Empirical Studies ◽  
School Curriculum ◽  
Educational Design ◽  
Current Trends ◽  
Educational Design Research ◽  
Creative Learning ◽  
Uncertain Future ◽  
The Impact

Cultivating children’s creativity and imagination is fundamental to preparing them for an increasingly complex and uncertain future. Engaging in creative learning enables children to think independently and critically, work cooperatively, and take risks while actively engaging in problem solving. While current trends in education, such as maker movements and computer science education, are dramatically expanding children’s opportunities for engagement in creative learning, comparatively few empirical studies explore how creative learning can be integrated into the school curriculum. The educational design research described in this paper focuses on a curriculum unit that enables students to engage with creative learning through computer programming activities while meeting curriculum goals. The data provided in this paper were drawn from three classroom tryouts, the results of which were used to drive an iterative design process. This paper also shares several insights on the impact of creative learning in curriculum teaching.

ALLELOPATHIC EFFECTS OF PARTHENIUM HYSTEROPHORUS ON GERMINATION OF SORGHUM SEEDS

2018 ◽  
Vol 6 (26) ◽  
Author(s):  
Jitendra Rajpoot
Keyword(s):  
Biological System ◽  
Growth And Development ◽  
Plant Virus ◽  
Evolutionary Origin ◽  
Plant Interactions ◽  
Biological Organization ◽  
Plant Soil ◽  
System A ◽  
Allelopathic Effects ◽  
Plant Plant

International Allelopathy Society has redefined Allelopathy as any process involving secondary metabolities produced by plants, algae, bacteria, fungi and viruses that influences the growth and development of agricultural and biological system; a study of the functions of secondary metabolities, their significance in biological organization, their evolutionary origin and elucidation of the mechanisms involving plant-plant, plant-microorganisms, plant-virus, plant-insect, plant-soil-plant interactions.

Behavioral Law and Economics

2018 ◽  
Author(s):  
Eyal Zamir ◽  
Doron Teichman
Keyword(s):  
Economic Analysis ◽  
Bounded Rationality ◽  
Law And Economics ◽  
Empirical Studies ◽  
Securities Regulation ◽  
Critical Examination ◽  
Entire Body ◽  
Economic Analysis Of Law ◽  
Behavioral Law And Economics ◽  
The Impact

In the past few decades, economic analysis of law has been challenged by a growing body of experimental and empirical studies that attest to prevalent and systematic deviations from the assumptions of economic rationality. While the findings on bounded rationality and heuristics and biases were initially perceived as antithetical to standard economic and legal-economic analysis, over time they have been largely integrated into mainstream economic analysis, including economic analysis of law. Moreover, the impact of behavioral insights has long since transcended purely economic analysis of law: in recent years, the behavioral movement has become one of the most influential developments in legal scholarship in general. Behavioral Law and Economics offers a state-of-the-art overview of the field. The book surveys the entire body of psychological research underpinning behavioral analysis of law, and critically evaluates the core methodological questions of this area of research. The book then discusses the fundamental normative questions stemming from the psychological findings on bounded rationality, and explores their implications for establishing the aims of legislation, and the means of attaining them. This is followed by a systematic and critical examination of the contributions of behavioral studies to all major fields of law—property, contracts, consumer protection, torts, corporate, securities regulation, antitrust, administrative, constitutional, international, criminal, and evidence law—as well as to the behavior of key players in the legal arena: litigants and judicial decision-makers.

Psychology: Volume 1

2019 ◽  
Keyword(s):  
Positive Psychology ◽  
Human Life ◽  
Empirical Studies ◽  
Real Life ◽  
Human Beings ◽  
Cognitive Capability ◽  
Affective Processes ◽  
Abstract Level ◽  
The Impact ◽  
Cognition And Affect

This survey of research on psychology in five volumes is a part of a series undertaken by the ICSSR since 1969, which covers various disciplines under social science. Volume One of this survey, Cognitive and Affective Processes, discusses the developments in the study of cognitive and affective processes within the Indian context. It offers an up-to-date assessment of theoretical developments and empirical studies in the rapidly evolving fields of cognitive science, applied cognition, and positive psychology. It also analyses how pedagogy responds to a shift in the practices of knowing and learning. Additionally, drawing upon insights from related fields it proposes epithymetics–desire studies – as an upcoming field of research and the volume investigates the impact of evolving cognitive and affective processes in Indian research and real life contexts. The development of cognitive capability distinguishes human beings from other species and allows creation and use of complex verbal symbols, facilitates imagination and empowers to function at an abstract level. However, much of the vitality characterizing human life is owed to the diverse emotions and desires. This has made the study of cognition and affect as frontier areas of psychology. With this in view, this volume focuses on delineating cognitive scientific contributions, cognition in educational context, context, diverse applications of cognition, psychology of desire, and positive psychology. The five chapters comprising this volume have approached the scholarly developments in the fields of cognition and affect in innovative ways, and have addressed basic as well applied issues.

scholarly journals Does Social Support Affect the Health of the Elderly in Rural China? A Meta-Analysis Approach

2019 ◽  
Vol 16 (18) ◽  
pp. 3471 ◽  
Author(s):  
Natuya Zhuori ◽  
Yu Cai ◽  
Yan Yan ◽  
Yu Cui ◽  
Minjuan Zhao
Keyword(s):  
Social Support ◽  
Rural Areas ◽  
Rural China ◽  
Statistical Significance ◽  
Empirical Studies ◽  
Relevant Literature ◽  
The Elderly ◽  
Significant Difference ◽  
Meta Regression ◽  
The Impact

As the trend of aging in rural China has intensified, research on the factors affecting the health of the elderly in rural areas has become a hot issue. However, the conclusions of existing studies are inconsistent and even contradictory, making it difficult to form constructive policies with practical value. To explore the reasons for the inconsistent conclusions drawn by relevant research, in this paper we constructed a meta-regression database based on 65 pieces of relevant literature published in the past 25 years. For more valid samples to reduce publication bias, we also set the statistical significance of social support to the health of the elderly in rural areas as a dependent variable. Finally, combined with multi-dimensional social support and its implications for the health of the elderly, meta-regression analysis was carried out on the results of 171 empirical studies. The results show that (1) subjective support rather than objective support can have a significant impact on the health of the elderly in rural areas, and there is no significant difference between other dimensions of social support and objective support; (2) the health status of the elderly in rural areas in samples involving western regions is more sensitive to social support than that in samples not involving the western regions; (3) among the elderly in rural areas, social support for the older male elderly is more likely to improve their health than that for the younger female elderly; and (4) besides this, both data sources and econometric models greatly affect the heterogeneity of the effect of social support on the health of the elderly in rural areas, but neither the published year nor the journal is significant. Finally, relevant policies and follow-up studies on the impact of social support on the health of the elderly in rural areas are discussed.

Sign in / Sign up

Export Citation Format

Share Document