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Fundamental axes of variation in plant traits result from trade-offs between costs and benefits of resource-use strategies at the leaf scale. However, it is unclear whether similar trade-offs propagate to the ecosystem level. Here, we test whether trait correlation patterns predicted by three well-known leaf- and plant-level coordination theories - the leaf economics spectrum, the global spectrum of plant form and function, and the least-cost hypothesis - are also observed between community mean traits and ecosystem processes. We combined ecosystem functional properties from FLUXNET sites, vegetation properties, and community mean plant traits into three corresponding principal component analyses. We find that the leaf economics spectrum (90 sites), the global spectrum of plant form and function (89 sites), and the least-cost hypothesis (82 sites) all propagate at the ecosystem level. However, we also find evidence of additional scale-emergent properties. Evaluating the coordination of ecosystem functional properties may aid the development of more realistic global dynamic vegetation models with critical empirical data, reducing the uncertainty of climate change projections.

All ecosystems contain both sources and sinks for atmospheric carbon (C). A change in their balance of net and gross ecosystem carbon uptake, ecosystem‐scale carbon use efficiency (CUEECO), is a change in their ability to buffer climate change. However, anthropogenic nitrogen (N) deposition is increasing N availability, potentially shifting terrestrial ecosystem stoichiometry towards phosphorus (P) limitation. Depending on how gross primary production (GPP, plants alone) and ecosystem respiration (RECO, plants and heterotrophs) are limited by N, P or associated changes in other biogeochemical cycles, CUEECO may change. Seasonally, CUEECO also varies as the multiple processes that control GPP and respiration and their limitations shift in time. We worked in a Mediterranean tree‐grass ecosystem (locally called 'dehesa') characterized by mild, wet winters and summer droughts. We examined CUEECO from eddy covariance fluxes over 6 years under control, +N and + NP fertilized treatments on three timescales: annual, seasonal (determined by vegetation phenological phases) and 14‐day aggregations. Finer aggregation allowed consideration of responses to specific patterns in vegetation activity and meteorological conditions. We predicted that CUEECO should be increased by wetter conditions, and successively by N and NP fertilization. Milder and wetter years with proportionally longer growing seasons increased CUEECO, as did N fertilization, regardless of whether P was added. Using a generalized additive model, whole ecosystem phenological status and water deficit indicators, which both varied with treatment, were the main determinants of 14‐day differences in CUEECO. The direction of water effects depended on the timescale considered and occurred alongside treatment‐dependent water depletion. Overall, future regional trends of longer dry summers may push these systems towards lower CUEECO. [ABSTRACT FROM AUTHOR]

Aim: To identify challenges faced by dental interns in the workforce and to suggest Pacific Island Countries (PIC) on further research in this area. Materials and Methods: A comprehensive search of Medline, Embase, Scopus and ProQuest databases was conducted using relevant keywords. All studies, published from 1st January 2000 to 31st January 2021, were taken into consideration. Removal of duplicates and screening the full-text articles using eligibility criteria were used to finalise the number of articles. The significant findings and conclusions were extracted and grouped under themes. Results: A total of 16 studies met the inclusion criteria, involving dental interns, medical interns, postgraduate and undergraduate. Five themes were identified as the main challenges faced by dental interns in the workplace including workplace bullying, handling medical emergencies, community placement, lack of interdisciplinary approach and poor record keeping. Conclusion: There is a need for PIC to conduct research and surveys, to identify the challenges its dental interns may be facing. This will create an ideal foundation from which strategies and initiatives can be implemented and enforced in the dental internship programme. Ensuring that oral health services are delivered efficiently and oral status of the Pacific is not compromised. [ABSTRACT FROM AUTHOR]

All ecosystems are simultaneously a source and a sink of atmospheric carbon (C). A change in their balance of net and gross ecosystem carbon uptake, ecosystem-scale carbon use efficiency (CUEECO), is a change in their ability to buffer climate change. Anthropogenic nitrogen (N) deposition is increasing N availability, potentially shifting terrestrial ecosystem stoichiometry towards phosphorus (P) limitation. Depending on how gross primary production (GPP, plants alone) and ecosystem respiration (RECO, plants and heterotrophs) are limited by N, P, or associated changes in other biogeochemical cycles, CUEECO may change. Seasonally, CUEECO also varies as GPP is more coupled to the growing season than respiration. We worked in a Mediterranean tree-grass ecosystem (locally called 'dehesa') characterized by mild, wet winters and summer droughts. We examined CUEECO from eddy covariance fluxes over six years under control, +N and +NP fertilized treatments on three timescales: annual, seasonal (determined by vegetation phenophase) and two-weekly aggregations. Finer aggregation allowed consideration of responses to specific vegetation and meteorological conditions. We predicted that CUEECO should be increased by wetter conditions, and by NP fertilization. Milder and wetter years with proportionally longer growing seasons increased CUEECO, as did N fertilization, regardless of whether P was added. Using a generalized additive model, whole ecosystem vegetation status and water deficit indicators, which both varied with treatment, were the main determinants of biweekly differences in CUEECO. The direction of water effects depended on the timescale considered and occurred alongside treatment-dependent water depletion. [ABSTRACT FROM AUTHOR]

Ecosystem manipulative experiments are a powerful tool to understand terrestrial ecosystem responses to global change because they measure real responses in real ecosystems and yield insights into causal relationships. However, their scope is limited in space and time due to cost and labour intensity. This makes generalising results from such experiments difficult, which creates a conceptual gap between local-scale process understanding and global-scale future predictions. Recent efforts have seen results from such experiments used in combination with dynamic global vegetation models, most commonly to evaluate model predictions under global change drivers. However, there is much more potential in combining models and experiments. Here, we discuss the value and potential of a workflow for using ecosystem experiments together with process-based models to enhance the potential of both. We suggest that models can be used prior to the start of an experiment to generate hypotheses, identify data needs, and in general guide experimental design. Models, when adequately constrained with observations, can also predict variables which are difficult to measure frequently or at all, and together with the data they can provide a more complete picture of ecosystem states. Finally, models can be used to help generalise the experimental results in space and time, by providing a framework in which process understanding derived from site-level experiments can be incorporated. We also discuss the potential for using manipulative experiments together with models in formalised model–data integration frameworks for parameter estimation and model selection, a path made possible by the increasing number of ecosystem experiments and diverse observation streams. The ideas presented here can provide a roadmap to future experiment–model studies. [ABSTRACT FROM AUTHOR]

Automating dynamic fine root data collection in the field is a longstanding challenge with multiple applications for cointerpretation and synthesis for ecosystem understanding. High frequency root data are only achievable with paired automated sampling and processing. However, automatic minirhizotron (root camera) instruments are still rare and data are often not collected in natural soils or analysed at high temporal resolution. Instruments must also be affordable for replication and robust under variable natural conditions. Here, we show a system built with off-the-shelf parts which samples at sub-daily resolution. We paired this with a neural network to analyse all images collected. We performed two mesocosm studies and two field trials alongside ancillary data collection (soil CO2 efflux, temperature, and moisture content, and ‘PhenoCam’-derived above-ground dynamics). We produce robust and replicated daily time series of root dynamics under all conditions. Temporal root changes were a stronger driver than absolute biomass on soil CO2 efflux in the mesocosm. Proximal sensed above-ground dynamics and below-ground dynamics from minirhizotron data were not synchronized. Root properties extracted were sensitive to soil moisture and occasionally to time of day (potentially relating to soil moisture). This may only affect high frequency imagery and should be considered in interpreting such data. [ABSTRACT FROM AUTHOR]

The effect of nutrient availability on plant growth and the terrestrial carbon sink under climate change and elevated CO2 remains one of the main uncertainties of the terrestrial carbon cycle. This is partially due to the difficulty of assessing nutrient limitation at large scales over long periods of time. Consistent declines in leaf nitrogen (N) content and leaf δ15N have been used to suggest that nitrogen limitation has increased in recent decades, most likely due to the concurrent increase in atmospheric CO2. However, such data sets are often not straightforward to interpret due to the complex factors that contribute to the spatial and temporal variation in leaf N and isotope concentration. We use the land surface model (LSM) QUINCY, which has the unique capacity to represent N isotopic processes, in conjunction with two large data sets of foliar N and N isotope content. We run the model with different scenarios to test whether foliar δ15N isotopic data can be used to infer large‐scale N limitation and if the observed trends are caused by increasing atmospheric CO2, changes in climate or changes in sources and magnitude of anthropogenic N deposition. We show that while the model can capture the observed change in leaf N content and predict widespread increases in N limitation, it does not capture the pronounced, but very spatially heterogeneous, decrease in foliar δ15N observed in the data across the globe. The addition of an observation‐based temporal trend in isotopic composition of N deposition leads to a more pronounced decrease in simulated leaf δ15N. Our results show that leaf δ15N observations cannot, on their own, be used to assess global‐scale N limitation and that using such a data set in conjunction with an LSM can reveal the drivers behind the observed patterns. [ABSTRACT FROM AUTHOR]

Aim: The aim of this article was to identify factors that influence the retention and turnover of dental professionals and to provide a suggestion for Pacific nations. Materials and Methods: A literature survey was conducted for the full-text English articles which looked at factors that influence the retention and turnover of dental professionals, from January 1, 2000 to October 31, 2020. Results: In total, 328 papers were retrieved, which reduced to 282 following removal of duplicates. The abstracts were screened using the eligibility criteria; 36 were found to match the criteria. After screening the full-text articles, 24 were excluded, resulting in a total of 12 articles. The significant findings and conclusions were extracted and grouped under themes. Conclusion: Factors that have been found to motivate and retain staff in the workforce include good patient relationship and opportunities for further studies and career advancements. In contrast, work stress, musculoskeletal disease, and fragile patient-dentist relationship were found to demotivate dental professionals. Furthermore, the results of such a research could be used to implement workforce policies and strategies, which will aid in the retention of dental staff and prevent brain drain. Ultimately, this would ensure that oral health status of the Pacific is not compromised. [ABSTRACT FROM AUTHOR]