The Density of Nonprofit Organizations: Beyond Community Diversity and Resource Availability

AbstractPlant defenses are very diverse and often involve contrasted costs and benefits. Quantitative defenses, whose protective effect is dependent on the dose, are effective against a wide range of herbivores, but often divert energy from growth and reproduction. Qualitative defenses often have little allocation costs. However, while deterrent to some herbivores, they often incur costs through other interactions within the community (eg, decrease in pollination or attraction of other enemies). In the present work, we model the evolutionary dynamics of these two types of defenses, as well and the evolutionary dynamics of the herbivore niche. We assess the effects of such evolutionary dynamics for the maintenance of diversity within the plant-herbivore system, and for the functioning of such systems under various levels of resource availability. We show that the two types of defenses have different implications. Evolution of quantitative defenses often helps to maintain or even increase diversity, while evolution of qualitative defenses most often has a detrimental effect on species coexistence. From a functional point of view, increased resource availability selects for higher levels of quantitative defenses, which reduces top-down controls exerted by herbivores. Resource availability does not affect qualitative defenses, nor the evolution of the herbivore niche. The growing evidence that plant defenses are diverse in types, benefits and costs has large implications not only for the evolution of these traits, but also for their impacts on community diversity and ecosystem functioning.

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Resource stoichiometry shapes community invasion resistance via productivity-mediated species identity effects

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2018.2035 ◽

2018 ◽

Vol 285 (1893) ◽

pp. 20182035 ◽

Cited By ~ 4

Author(s):

Tianjie Yang ◽

Gang Han ◽

Qingjun Yang ◽

Ville-Petri Friman ◽

Shaohua Gu ◽

...

Keyword(s):

Resource Availability ◽

Relative Concentration ◽

Microbial Community Composition ◽

Community Diversity ◽

Invasion Resistance ◽

Resident Species ◽

Negative Effects ◽

Species Identity ◽

Community Resistance ◽

The Mean

Diversity–invasion resistance relationships are often variable and sensitive to environmental conditions such as resource availability. Resource stoichiometry, the relative concentration of different elements in the environment, has been shown to have strong effects on the physiology and interactions between different species. Yet, its role for diversity–invasion resistance relationships is still poorly understood. Here, we explored how the ratio of nitrogen (N) and phosphorus affects the productivity and invasion resistance of constructed microbial communities by a plant pathogenic bacterium, Ralstonia solanacearum . We found that resource stoichiometry and species identity effects affected the invasion resistance of communities. Both high N concentration and resident community diversity constrained invasions, and two resident species, in particular, had strong negative effects on the relative density of the invader and the resident community productivity. While resource stoichiometry did not affect the mean productivity of the resident community, it favoured the growth of two species that strongly constrained invasions turning the slope of productivity–invasion resistance relationship more negative. Together our findings suggest that alterations in resource stoichiometry can change the community resistance to invasions by having disproportionate effects on species growth, potentially explaining changes in microbial community composition under eutrophication.

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Seasonality, Resource Availability, and Community Diversity in Tropical Bird Communities

The American Naturalist ◽

10.1086/283121 ◽

1976 ◽

Vol 110 (976) ◽

pp. 973-994 ◽

Cited By ~ 106

Author(s):

James R. Karr

Keyword(s):

Resource Availability ◽

Bird Communities ◽

Community Diversity ◽

Tropical Bird

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A simple linear relationship between resource availability and microbial community diversity

10.1101/2020.09.12.294660 ◽

2020 ◽

Author(s):

Martina Dal Bello ◽

Hyunseok Lee ◽

Akshit Goyal ◽

Jeff Gore

Keyword(s):

Microbial Community ◽

Microbial Communities ◽

Linear Relationship ◽

Resource Availability ◽

Carbon Sources ◽

Community Diversity ◽

Microbial Community Diversity ◽

Wide Range ◽

Simple Linear Relationship

AbstractMicrobial community diversity is pivotal for the functioning of our planet, but its drivers are still unclear, in particular the role of resource number and identity. To fill this gap, we studied the assembly of hundreds of soil-derived microbial communities on a wide range of well-defined resource environments, from single carbon sources to combinations of up to 16. We found a remarkable diversity in single resources but a linear one-by-one increase in the number of species with the number of additional resources. We show, both experimentally and theoretically, that both these observations could originate from generalist and specialist taxa interacting in a modular fashion within the community. Since generalists and specialists are ubiquitous in natural microbiomes, our results might apply to a variety of different ecological settings, providing a framework to predict how community diversity responds to changes in resource availability.One Sentence SummaryWhile many species coexist in single resources, community diversity only increases one-by-one as more resources are added.

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Twitter Usage Using Common Reference to Tinnitus

American Journal of Audiology ◽

10.1044/2020_aja-19-00055 ◽

2020 ◽

Vol 29 (2) ◽

pp. 206-217

Author(s):

Jianyuan Ni ◽

Monica L. Bellon-Harn ◽

Jiang Zhang ◽

Yueqing Li ◽

Vinaya Manchaiah

Keyword(s):

Nonprofit Organizations ◽

Temporal Trends ◽

Temporal Analysis ◽

Cross Sectional ◽

For Profit ◽

Common Reference ◽

Personal Experiences ◽

Twitter Users ◽

Sectional Analysis ◽

Share Information

Objective The objective of the study was to examine specific patterns of Twitter usage using common reference to tinnitus. Method The study used cross-sectional analysis of data generated from Twitter data. Twitter content, language, reach, users, accounts, temporal trends, and social networks were examined. Results Around 70,000 tweets were identified and analyzed from May to October 2018. Of the 100 most active Twitter accounts, organizations owned 52%, individuals owned 44%, and 4% of the accounts were unknown. Commercial/for-profit and nonprofit organizations were the most common organization account owners (i.e., 26% and 16%, respectively). Seven unique tweets were identified with a reach of over 400 Twitter users. The greatest reach exceeded 2,000 users. Temporal analysis identified retweet outliers (> 200 retweets per hour) that corresponded to a widely publicized event involving the response of a Twitter user to another user's joke. Content analysis indicated that Twitter is a platform that primarily functions to advocate, share personal experiences, or share information about management of tinnitus rather than to provide social support and build relationships. Conclusions Twitter accounts owned by organizations outnumbered individual accounts, and commercial/for-profit user accounts were the most frequently active organization account type. Analyses of social media use can be helpful in discovering issues of interest to the tinnitus community as well as determining which users and organizations are dominating social network conversations.

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Measuring Impact of Stress in Sandwich Generation Caring for Demented Parents

GeroPsych ◽

10.1024/1662-9647/a000114 ◽

2014 ◽

Vol 27 (4) ◽

pp. 171-179 ◽

Cited By ~ 6

Author(s):

Laurence M. Solberg ◽

Lauren B. Solberg ◽

Emily N. Peterson

Keyword(s):

Factor Analysis ◽

Exploratory Factor Analysis ◽

Social Worker ◽

Resource Availability ◽

Well Being ◽

Sandwich Generation ◽

Item Questionnaire ◽

Significant Difference ◽

Adult Caregivers ◽

The Impact

Stress in caregivers may affect the healthcare recipients receive. We examined the impact of stress experienced by 45 adult caregivers of their elderly demented parents. The participants completed a 32-item questionnaire about the impact of experienced stress. The questionnaire also asked about interventions that might help to reduce the impact of stress. After exploratory factor analysis, we reduced the 32-item questionnaire to 13 items. Results indicated that caregivers experienced stress, anxiety, and sadness. Also, emotional, but not financial or professional, well-being was significantly impacted. There was no significant difference between the impact of caregiver stress on members from the sandwich generation and those from the nonsandwich generation. Meeting with a social worker for resource availability was identified most frequently as a potentially helpful intervention for coping with the impact of stress.

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