Alain Finn

Ecological data are increasingly collected by networks of collaborators using replicated designs and methods, which can significantly improve the quality and quantity of data throughout the ecological niche and geographic range of species or communities. The coordinated generation and management of data is critical for producing datasets (Standard Data Products) across multiple sites that can be used by different researchers, over extended time periods and for multiple purposes. We describe and use a Quality Assurance framework for the design, collection and production of reproducible Standard Data Products for distributed ecology projects. We identified six critical project elements of a Quality Assurance framework (QA1‐6) to produce ecological Standard Data Products with high immediate and future value. We applied the Quality Assurance framework to the Plantpopnet project as a case‐study. Plantpopnet is a coordinated distributed system for population macroecology using the model species Plantago lanceolata . We mapped Plantpopnet activities to the Quality Assurance Framework as follows: (QA1) Measurable objectives : research project objectives with data requirements, (QA2) Process control : governance policies, (QA3) Project specific procedures : model organism selection and data collection protocol, (QA4) Supporting production of high quality data : recruitment, retention and engagement of participants, (QA5) Data management : data management plan and reproducible data cleaning workflow, (QA6) Production and management of outputs : Standard Data Products and papers. Explicit use of Quality Assurance, project and data management tools together with standardised ecological methods facilitated the design, collection, maintenance and sustainability of high‐quality data products. We provide a Quality Assurance framework together with governance documents, code and data for a reproducible Standard Data Product. This framework supports a distributed funding model which can be sustainably applied to facilitate future research and applications of coordinated distributed ecology projects.

Individual plant size often determines the vital rates of growth, survival and reproduction. However, size can be measured in several ways (e.g. height, biomass, leaf length). There is no consensus on the best size metric for modelling vital rates in plants. Demographic datasets are expanding in geographic extent, leading to choices about how to represent size for the same species in multiple ecological contexts. If the choice of size variable varies among locations, inter‐population comparative demography increases in complexity. Here, we present a framework to perform size metric selection in large‐scale demographic studies. We highlight potential pitfalls and suggest methods applicable to diverse study organisms. We assessed the performance of five different size metrics for the perennial herb Plantago lanceolata , across 55 populations on three continents within its native and non‐native ranges, using the spatially replicated demographic dataset PlantPopNet. We compared the performance of each candidate size metric for four vital rates (growth, survival, flowering probability and reproductive output) using generalized linear mixed models. We ranked the candidate size metrics based on their overall performance (highest generalized R ² ) and homogeneity of performance across populations (lowest total magnitude of, and variance in, population‐level error). While all size variables performed well for modelling vital rates, the number of leaves (modelled as a discrete variable, without transformation) was selected as the best size metric, followed by leaf length. We show how to interrogate potential trade‐offs between overall explanatory power and homogeneity of predictions across populations in any organism. Synthesis . Size is an important determinant of vital rates. Using a dataset of unprecedented spatial extent, we find (a) consistent size‐based models of growth, survival and reproduction across native and non‐native populations of this cosmopolitan plant species and (b) that several tested size metrics perform similarly well. This is encouraging for large‐scale demographic studies and for comparative projects using different size metrics, as they may be robust to this methodological difference.

Determining how individual species can act to moderate the stability of entire ecosystems is a pressing challenge in a world undergoing rapid environmental change. Here, we show that even very weakly interacting species with no discernible effect on ecological dynamics can contribute substantially to ecosystem stability. Further, the nature of this contribution depends on biotic context, and both the type and complexity of interspecific interactions in the community. By manipulating multitrophic aquatic microcosm communities experimentally, we found that the contributions of a bacteriophage parasite to overall system stability following a pulse perturbation were variously stabilizing, destabilizing and neutral, depending on the presence of competitor or predator species of its bacterial host. This was despite the phage itself having no detectable effect on the biomass or growth rates of its host. Our results demonstrate the pivotal importance of both weak and indirect interactions in moderating the stability of whole ecological networks, and have profound implications for our ability to predict the consequences of perturbations on ecosystems.

Our understanding of plant functional trait variation among populations and how this relates to local adaptation to environmental conditions is largely shaped by above‐ground traits. However, we might expect below‐ground traits linked to resource acquisition and conservation to vary among populations that experience different environmental conditions. Alternatively, below‐ground traits might be highly plastic in response to growing conditions, such as availability of soil resources and association with symbiont arbuscular mycorrhizal fungi (AMF). We assessed (i) the strength of among‐population variation in above‐ and below‐ground traits, (ii) the effects of growing conditions on among‐population variation and (iii) whether variation among populations is linked to source environment conditions, in a globally distributed perennial Plantago lanceolata. Using seeds from 14 populations across three continents, we grew plants in a common garden experiment and measured leaf and root traits linked to resource acquisition and water conservation. We included two sets of experimental treatments (high or low water availability; with and without AMF inoculation), which enabled us to assess trait responses to growing conditions. Across treatments, the percentage of root trait variation explained by populations and continents was 9%–26%, compared to 7%–20% for leaf trait variation. From principal component analysis (PCA), the first PC axis for both root and leaf traits largely reflected plant size, while the second PC broadly captured mass allocation. Root mass allocation (PC 2) was related to mean annual temperature and mean moisture index, indicating that populations from cooler, wetter environments had longer, thinner roots. However, we found little support for a relationship between source environment and leaf trait PCs, root system size (PC1) or individual traits. Water availability and AMF inoculation effects on size were consistent among populations, with larger plants under AMF inoculation, and less mass allocation to leaves under lower water availability. Plantago lanceolata shows substantial population‐level variation in a suite of root traits, but that variation is only partially linked to the source environmental variables studied. Despite considerable differences in source abiotic environments, geographically separated populations have retained a strong and similar capacity for phenotypic plasticity both above and below‐ground. Read the free Plain Language Summary for this article on the Journal blog.

Droughts can strongly affect grassland productivity and biodiversity, but responses differ widely. Nutrient availability may be a critical factor explaining this variation, but is often ignored in analyses of drought responses. Here, we used a standardized nutrient addition experiment covering 10 European grasslands to test if full‐factorial nitrogen, phosphorus, and potassium addition affected plant community responses to inter‐annual variation in drought stress and to the extreme summer drought of 2018 in Europe. We found that nutrient addition amplified detrimental drought effects on community aboveground biomass production. Drought effects also differed between functional groups, with a negative effect on graminoid but not forb biomass production. Our results imply that eutrophication in grasslands, which promotes dominance of drought‐sensitive graminoids over forbs, amplifies detrimental drought effects. In terms of climate change adaptation, agricultural management would benefit from taking into account differential drought impacts on fertilized versus unfertilized grasslands, which differ in ecosystem services they provide to society.

When plants establish outside their native range, their ability to adapt to the new environment is influenced by both demography and dispersal. However, the relative importance of these two factors is poorly understood. To quantify the influence of demography and dispersal on patterns of genetic diversity underlying adaptation, we used data from a globally distributed demographic research network comprising 35 native and 18 nonnative populations of Plantago lanceolata . Species-specific simulation experiments showed that dispersal would dilute demographic influences on genetic diversity at local scales. Populations in the native European range had strong spatial genetic structure associated with geographic distance and precipitation seasonality. In contrast, nonnative populations had weaker spatial genetic structure that was not associated with environmental gradients but with higher within-population genetic diversity. Our findings show that dispersal caused by repeated, long-distance, human-mediated introductions has allowed invasive plant populations to overcome environmental constraints on genetic diversity, even without strong demographic changes. The impact of invasive plants may, therefore, increase with repeated introductions, highlighting the need to constrain future introductions of species even if they already exist in an area.