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AIM: To conceptualize the mechanistic pathways of the nurse‐plant syndrome by life‐form and to identify the implications of positive plant–plant interactions for landscape and evolutionary ecology. LOCATION: Global. METHODS: We conducted a quantitative review examining 298 articles to categorize the literature on nurse‐plant interactions based on geographic region, mechanism of facilitation, ecological hypothesis and nurse life‐form. RESULTS: A total of nine different nurse mechanisms were identified and two were classified as meta‐mechanisms. We found that shrubs were the dominant nurse life‐form (46% of total studies) and that studies of positive plant interactions were most frequent in areas of high abiotic stress. Nurse‐plant studies were also distributed unevenly around the globe with nearly a quarter in the South American Andes and Spain. Studies testing the direct nurse–protégé interactions were the most frequently performed, including the ecophysiological responses of protégé species (32.2%). Research gaps identified in the nurse‐plant literature included indirect interactions and seed trapping as well as the large‐scale implications for landscape ecology and evolution. MAIN CONCLUSIONS: Nurse plants are often considered keystone species because they commonly structure plant communities. This is an important confirmatory finding in many respects, but it is also novel in that it challenges traditional plant ecology theory and has important implications for landscape‐level dynamics over time. The categorization of mechanisms proposed provides a conceptual framework useful for organizing the research to date and can accelerate linkages with theory and application by identifying important connections. It is becoming increasingly apparent that future studies of the nurse‐plant syndrome must decouple and consider multiple mechanisms of interaction to explain the processes that influence community structure, particularly in high‐stress conditions, given a changing climate and potential shifts in biodiversity.

There is extensive choice in R to support meta‐analyses. Two packages in this ecosystem include meta and metafor and provide an excellent opportunity to apply a structured checklist previously developed for contrasts between R packages relevant to challenges in ecology and evolution. Meta is a direct, intuitive choice for rapid implementation of general meta‐analytical statistics. Metafor is a comprehensive package best suited for relatively more complex models. Both packages provide estimates of heterogeneity, excellent visualization tools, and functions to explore publication bias. The package metafor has a steeper learning curve but greater rewards. Reference to the learning curve and capacities of the statistical software Stata provided a benchmark outside the R ecosystem and confirmed the consistency in statistics. The usefulness of meta‐analyses is not just in the synthesis of the research but in the process of doing the scientific synthesis. Reporting of contrasts and checks for robust statistics is an important contribution to more transparent and reproducible scientific syntheses. Meta‐analyses are common and increasing in ecology and evolution. Here, we contrast two common R packages used in our field and further provide an explanation and contrast with another common tool.

Narrative reviews are dead. Long live systematic reviews (and meta‐analyses). Synthesis in many forms is now a driving force in ecology. Advances in open data for ecology and new tools provide vastly improved capacity for novel, emergent knowledge synthesis in our discipline. Systematic reviews and meta‐analyses are two formal synthesis opportunities for ecologists that are now accepted as traditional publications, but the scope of validated syntheses will continue to expand. To date, systematic reviews are rarely used whilst the rate of meta‐analyses published in ecological journals is increasing exponentially. Systematic reviews provide an overview of the literature landscape for a topic, and meta‐analyses examine the strength of evidence integrated across different studies. Effective synthesis benefits from both approaches, but better data reporting and additional advances in the culture of sharing data, code, analytics, workflows, methods and also ideas will further energize these efforts. At this junction, synthetic efforts that include systematic reviews and meta‐analyses should continue as stand‐alone publications. This is a necessary step in the evolution of synthesis in our discipline. Nonetheless, they are still evolving tools, and meta‐analyses in particular are simply an extended set of statistical tests. Admittedly, understanding the statistics and assumptions influence how we conduct synthesis much as statistical choices often shape experimental design, i.e. ANOVA versus regression‐based experiments, but statistics do not make the paper. Current steps – primary research articles need to more effectively report evidence, sharing scientific products should expand, systematic reviews should be used to identify research gaps/delineate literature landscapes, and meta‐analyses should be used to examine evidence patterns to further predictive ecology.

Conferences provide an invaluable set of opportunities for professional development. Online, virtual, and distributed conferences do not necessarily mean less opportunity for growth and innovation in science but varied and novel options for communicating the scientific process. Open science and many existing tools are in place in the practice of contemporary ecology and evolution to provide latitude for a much broader scope of sharing and thus learning from conferences. A brief overview of the science supporting online conferences and a highlight of some of the open science concepts in ecology and evolution are provided here to enable better learning through better planning for online conferences. Online conferences are a necessity. We can use this an opportunity in ecology and evolution to enable better learning and affect social good.

The mechanisms supporting positive ecological interactions are important. Foundation species can structure desert biodiversity by facilitating seedbanks of annual plants, but the direct and indirect mechanisms of shrub effects on seedbank have not been experimentally decoupled. We conducted the first test of shrubs increasing seedbank densities through direct effects on the seedbank (i.e. shrub seed-trapping, animal-mediated dispersal) and indirect effects by facilitating the annual plant community (i.e. seed deposition, annual seed-trapping). Two distinct desert ecosystems were used to contrast transient seedbank densities in shrub and open microsites by manipulating annual plant density and the presence of the persistent seedbank. We measured transient seedbank densities at the end of the growing season by collecting soil samples and extracting seeds from each respective treatment. Transient seedbank densities were greatest in shrub canopies and with relatively higher annual plant densities. The persistent seedbank contributed to transient seedbank densities only in one desert and in the open microsite. Shrubs indirectly increased seedbank densities by facilitation the seed production of the annual plants. Therefore, shrubs are increasing seedbank independently of the annual plant community, likely through trapping effects, and dependently by facilitating seed production of the annuals. These findings provide evidence for a previously undescribed mechanism that supports annual seedbanks and thus desert biodiversity. We also identify shrubs as being significant drivers of desert plant communities and emphasize the need to consider multiple mechanisms to improve our ability to predict the response of ecosystems to change.

1. The stress-gradient hypothesis (SGH) predicts that the frequency of facilitative and competitive interactions will vary inversely across abiotic stress gradients, with facilitation being more common in conditions of high abiotic stress relative to more benign abiotic conditions. With notable exceptions, most tests of the SGH have studied the interaction between a single pair or a few pairs of species, and thus have evaluated shifts in the magnitude and direction of pair-wise interactions along stress gradients, rather than shifts in the general frequency of interactions. 2. The SGH has been supported by numerous studies in many ecosystems, has provided a crucial foundation for studying the interplay between facilitation and competition in plant communities, and has a high heuristic value. However, recent empirical research indicates that factors like the variation among species and the nature of the stress gradient studied add complexity not considered in the SGH, creating an opportunity to extend the SGH's general conceptual framework. 3. We suggest that one approach for extending the SGH framework is to differentiate between the original idea of how 'common' interactions might be along stress gradients and the ubiquitous empirical approach of studying shifts in the strength of pair-wise interactions. Furthermore, by explicitly considering the life history of the interacting species (relative tolerance to stress vs. competitive ability) and the characteristics of the stress factor (resource vs. non-resource) we may be able to greatly refine specific predictions relevant to the SGH. 4. We propose that the general pattern predicted by the SGH would hold more frequently for some combinations of life histories and stress factor, particularly when the benefactor and beneficiary species are mostly competitive and stress-tolerant, respectively. However, we also predict that other combinations are likely to yield different results. For example, the effect of neighbours can be negative at both ends of the stress gradient when both interacting species have similar 'competitive' or 'stress-tolerant' life histories and the abiotic stress gradient is driven by a resource (e.g. water). 5. Synthesis. The extension of the SGH presented here provides specific and testable hypotheses to foster research and helps to reconcile potential discrepancies among previous studies. It represents an important step in incorporating the complexity and species-specificity of potential outcomes into models and theories addressing how plant-plant interactions change along stress gradients.

About the Authors: Christopher J. Lortie * E-mail: lortie@yorku.ca Affiliations Department of Biology, York University, Toronto, Ontario, Canada, National Center for Ecological Analysis and Synthesis, UCSB, Santa Barbara, California, United States of America ORCID http://orcid.org/0000-0002-4291-7023Citation: Lortie CJ (2017) Ten simple rules for short and swift presentations. Scientific communication has evolved because it does not have to happen only at the final stages of a research endeavor but can be used to engage the public to fund the research (https://scifundchallenge.org), participate in the data collection (http://www.audubon.org/conservation/science/christmas-bird-count), share or crowd source the code and analyses (https://github.com), and process the evidence (https://www.zooniverse.org). Boot-camp training workshops are now also offered (i.e., American Institute of Biological Sciences [AIBS]), and discussion of how academics use brief communications, such as social media tools, is present within the primary research literature [9-11]. An interesting related opportunity has emerged that, in some respects, bridges the gap between lengthy, detailed presentations of scientific findings and “sound bites” such as headlines or short press releases appropriate for media reporting: very short, swift presentations. The specific guidelines vary, but the slide deck is often limited by a set number of slides, or the presentation is limited by very strict, short time constraints (such as found with lightning talks). [...]as a general rule-of-thumb, talks prepared for a more general public audience should emphasize the implications of the science and use direct, natural language and visual analogies (instead of necessarily always showing complex evidence or primary data). Talks for scientific colleagues must also embrace...

The programming language R is widely used in many fields. We explored the extent of reported R use in the field of ecology using the Web of Science and text mining. We analyzed the frequencies of R packages reported in more than 60,000 peer‐reviewed articles published in 30 ecology journals during a 10‐yr period ending in 2017. The number of studies reported using R as their primary tool in data analysis increased linearly from 11.4% in 2008 to 58.0% in 2017. The top 10 packages reported were lme4, vegan, nlme, ape, MuMIn, MASS, mgcv, ade4, multcomp, and car. The increasing popularity of R has most likely furthered open science in ecological research because it can improve reproducibility of analyses and captures workflows when scripts and codes are included and shared. These findings may not be entirely unique to R because there are other programming languages used by ecologists, but they do strongly suggest that given the relatively high frequency of reported use of R, it is a significant component of contemporary analytics in the field of ecology.

Alpine ecosystems are important globally with high levels of endemic and rare species. Given that they will be highly impacted by climate change, understanding biotic factors that maintain diversity is critical. Silene acaulis is a common alpine nurse plant shown to positively influence the diversity and abundance of organisms--predominantly other plant species. The hypothesis that cushion or nurse plants in general are important to multiple trophic levels has been proposed but rarely tested. Alpine arthropod diversity is also largely understudied worldwide, and the plant-arthropod interactions reported are mostly negative, that is,. herbivory. Plant and arthropod diversity and abundance were sampled on S. acaulis and at paired adjacent microsites with other non-cushion forming vegetation present on Whistler Mountain, B.C., Canada to examine the relative trophic effects of cushion plants. Plant species richness and abundance but not Simpson's diversity index was higher on cushion microsites relative to other vegetation. Arthropod richness, abundance, and diversity were all higher on cushion microsites relative to other vegetated sites. On a microclimatic scale, S. acaulis ameliorated stressful conditions for plants and invertebrates living inside it, but the highest levels of arthropod diversity were observed on cushions with tall plant growth. Hence, alpine cushion plants can be foundation species not only for other plant species but other trophic levels, and these impacts are expressed through both direct and indirect effects associated with altered environmental conditions and localized productivity. Whilst this case study tests a limited subset of the membership of alpine animal communities, it clearly demonstrates that cushion-forming plant species are an important consideration in understanding resilience to global changes for many organisms in addition to other plants.

New evidence demonstrates that facilitation plays a crucial role even at the edge of life in Maritime Antarctica. These findings are interpreted as support for the stress‐gradient hypothesis (SGH) – a dominant theory in plant community ecology that predicts that the frequency of facilitation directly increases with stress. A recent development to this theory, however, proposed that facilitation often collapses at the extreme end of stress and physical disturbance gradients. In this paper, we clarify the current debate on the importance of plant interactions at the edge of life by illustrating the necessity of separating the two alternatives to the SGH, namely the collapse of facilitation, and the switch from facilitation to competition occurring in water‐stressed ecosystems. These two different alternatives to the SGH are currently often amalgamated with each other, which has led to confusion in recent literature. We propose that the collapse of facilitation is generally due to a decrease in the effect of the nurse plant species, whilst the switch from facilitation to competition is driven by environmental conditions and strategy of the response species. A clear separation between those two alternatives is particularly crucial for predicting the role of plant–plant interactions in mediating species responses to global change.