Leaf-level coordination principles propagate to the ecosystem scale.

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.

A First-Class Simulation: In-Situ In-Flight Medical Emergencies Curriculum for Emergency Medicine Residents Aboard a Commercial Airliner.

INTRODUCTION: In-flight medical emergencies occur in an estimated one out of 604 flights. Responding in this environment poses a unique set of challenges unfamiliar to most emergency medicine (EM) providers, including physical space and resource limitations. We developed a novel high-fidelity in-situ training curriculum focused on frequent or high-risk in-flight medical scenarios while replicating this austere environment. METHODS: Our residency program coordinated with our local airport's chief of security and an airline-specific station manager to arrange the use of a grounded Boeing 737 commercial airliner during late evening/early morning hours. Eight stations reviewing in-flight medical emergency topics were reviewed, five of which were simulation scenarios. We created medical and first-aid kits that reflect equipment used by commercial airlines. Residents' self-assessed competency and medical knowledge were assessed both initially and post-curriculum using a standardized questionnaire. RESULTS: Forty residents attended the educational event as learners. Self-assessed competency and medical knowledge increased after curriculum participation. All tested aspects of self-assessed competency had a statistically significant increase from a mean of 15.04 to 29.20 out of a maximum score of forty. The mean medical knowledge score increased from 4.65 to 6.93 out of 10 maximum points. CONCLUSION: A five-hour in-situ curriculum for reviewing in-flight medical emergencies increased self-assessed competency and medical knowledge for EM and EM-internal medicine residents. The curriculum was overwhelmingly well-received by learners.

Antarctic Evacuation: A Retrospective Epidemiological Study of Medical Evacuations on US Military Aircraft in Antarctica.

BACKGROUND: The international community has shown increasing interest in the Arctic and Antarctic due to the value polar regions have in terms of environmental research, natural resources, and national defense. The US Government maintains several permanent research and military facilities in polar regions. Medical evacuation (MEDEVAC) from these facilities can be limited for prolonged periods of time due to their extreme climates. Published data regarding MEDEVACs from these facilities is extremely limited. METHODS: Evacuations on military aircraft registered in the Transportation Command Regulation and Command and Control Evacuation System (TRAC2ES) database in a previously de-identified dataset were queried for events from McMurdo, Antarctica. The data was analyzed to determine the number of evacuations, reasons for evacuation, and additional demographic data. RESULTS: There were 31 evacuations from McMurdo Station and Scott Amundsen South Pole Station for 29 unique patients recorded in the available TRAC2ES dataset. Reasons for evacuation included traumatic brain/head injury, behavioral health concerns, extremity injuries, pregnancy, and various other medical/surgical concerns. CONCLUSIONS: MEDEVAC was typically required for advanced diagnostic/treatment modalities or if a patient could no longer fulfill his/her duties. Most evacuations were not directly related to environmental exposure. Given the climate in polar regions can preclude timely evacuation for large periods of time, the need for evacuation must be anticipated and mitigated whenever possible. Better data is needed to guide staffing and mission planning in this remote location.

Novel technique for continuous pressure monitoring of esophageal balloon in balloon tamponade device for acute variceal bleed.

Acute variceal bleeding is a life-threatening emergency associated with high mortality. Balloon tamponade is required for refractory bleeding to allow stabilization for definitive therapy. Unfortunately, these devices are associated with iatrogenic complications such as esophageal necrosis and perforation. It is imperative to accurately measure the esophageal balloon pressure to limit these complications. We describe a novel technique for both initial and continuous pressure monitoring of the esophageal balloon.

Simulating environmentally-sensitive tree recruitment in vegetation demographic models.

Vegetation demographic models (VDMs) endeavor to predict how global forests will respond to climate change. This requires simulating which trees, if any, are able to recruit under changing environmental conditions. We present a new recruitment scheme for VDMs in which functional-type-specific recruitment rates are sensitive to light, soil moisture and the productivity of reproductive trees. We evaluate the scheme by predicting tree recruitment for four tropical tree functional types under varying meteorology and canopy structure at Barro Colorado Island, Panama. We compare predictions to those of a current VDM, quantitative observations and ecological expectations. We find that the scheme improves the magnitude and rank order of recruitment rates among functional types and captures recruitment limitations in response to variable understory light, soil moisture and precipitation regimes. Our results indicate that adopting this framework will improve VDM capacity to predict functional-type-specific tree recruitment in response to climate change, thereby improving predictions of future forest distribution, composition and function.

Variation in hydroclimate sustains tropical forest biomass and promotes functional diversity.

The fate of tropical forests under climate change is unclear as a result, in part, of the uncertainty in projected changes in precipitation and in the ability of vegetation models to capture the effects of drought-induced mortality on aboveground biomass (AGB). We evaluated the ability of a terrestrial biosphere model with demography and hydrodynamics (Ecosystem Demography, ED2-hydro) to simulate AGB and mortality of four tropical tree plant functional types (PFTs) that operate along light- and water-use axes. Model predictions were compared with observations of canopy trees at Barro Colorado Island (BCI), Panama. We then assessed the implications of eight hypothetical precipitation scenarios, including increased annual precipitation, reduced inter-annual variation, El Niño-related droughts and drier wet or dry seasons, on AGB and functional diversity of the model forest. When forced with observed meteorology, ED2-hydro predictions capture multiple BCI benchmarks. ED2-hydro predicts that AGB will be sustained under lower rainfall via shifts in the functional composition of the forest, except under the drier dry-season scenario. These results support the hypothesis that inter-annual variation in mean and seasonal precipitation promotes the coexistence of functionally diverse PFTs because of the relative differences in mortality rates. If the hydroclimate becomes chronically drier or wetter, functional evenness related to drought tolerance may decline.

Vegetation demographics in Earth System Models: A review of progress and priorities.

Numerous current efforts seek to improve the representation of ecosystem ecology and vegetation demographic processes within Earth System Models (ESMs). These developments are widely viewed as an important step in developing greater realism in predictions of future ecosystem states and fluxes. Increased realism, however, leads to increased model complexity, with new features raising a suite of ecological questions that require empirical constraints. Here, we review the developments that permit the representation of plant demographics in ESMs, and identify issues raised by these developments that highlight important gaps in ecological understanding. These issues inevitably translate into uncertainty in model projections but also allow models to be applied to new processes and questions concerning the dynamics of real-world ecosystems. We argue that stronger and more innovative connections to data, across the range of scales considered, are required to address these gaps in understanding. The development of first-generation land surface models as a unifying framework for ecophysiological understanding stimulated much research into plant physiological traits and gas exchange. Constraining predictions at ecologically relevant spatial and temporal scales will require a similar investment of effort and intensified inter-disciplinary communication.

Differences in xylem and leaf hydraulic traits explain differences in drought tolerance among mature Amazon rainforest trees.

Considerable uncertainty surrounds the impacts of anthropogenic climate change on the composition and structure of Amazon forests. Building upon results from two large-scale ecosystem drought experiments in the eastern Brazilian Amazon that observed increases in mortality rates among some tree species but not others, in this study we investigate the physiological traits underpinning these differential demographic responses. Xylem pressure at 50% conductivity (xylem-P50 ), leaf turgor loss point (TLP), cellular osmotic potential (πo ), and cellular bulk modulus of elasticity (ε), all traits mechanistically linked to drought tolerance, were measured on upper canopy branches and leaves of mature trees from selected species growing at the two drought experiment sites. Each species was placed a priori into one of four plant functional type (PFT) categories: drought-tolerant versus drought-intolerant based on observed mortality rates, and subdivided into early- versus late-successional based on wood density. We tested the hypotheses that the measured traits would be significantly different between the four PFTs and that they would be spatially conserved across the two experimental sites. Xylem-P50 , TLP, and πo , but not ε, occurred at significantly higher water potentials for the drought-intolerant PFT compared to the drought-tolerant PFT; however, there were no significant differences between the early- and late-successional PFTs. These results suggest that these three traits are important for determining drought tolerance, and are largely independent of wood density-a trait commonly associated with successional status. Differences in these physiological traits that occurred between the drought-tolerant and drought-intolerant PFTs were conserved between the two research sites, even though they had different soil types and dry-season lengths. This more detailed understanding of how xylem and leaf hydraulic traits vary between co-occuring drought-tolerant and drought-intolerant tropical tree species promises to facilitate a much-needed improvement in the representation of plant hydraulics within terrestrial ecosystem and biosphere models, which will enhance our ability to make robust predictions of how future changes in climate will affect tropical forests.

Confronting model predictions of carbon fluxes with measurements of Amazon forests subjected to experimental drought.

Considerable uncertainty surrounds the fate of Amazon rainforests in response to climate change. Here, carbon (C) flux predictions of five terrestrial biosphere models (Community Land Model version 3.5 (CLM3.5), Ecosystem Demography model version 2.1 (ED2), Integrated BIosphere Simulator version 2.6.4 (IBIS), Joint UK Land Environment Simulator version 2.1 (JULES) and Simple Biosphere model version 3 (SiB3)) and a hydrodynamic terrestrial ecosystem model (the Soil-Plant-Atmosphere (SPA) model) were evaluated against measurements from two large-scale Amazon drought experiments. Model predictions agreed with the observed C fluxes in the control plots of both experiments, but poorly replicated the responses to the drought treatments. Most notably, with the exception of ED2, the models predicted negligible reductions in aboveground biomass in response to the drought treatments, which was in contrast to an observed c. 20% reduction at both sites. For ED2, the timing of the decline in aboveground biomass was accurate, but the magnitude was too high for one site and too low for the other. Three key findings indicate critical areas for future research and model development. First, the models predicted declines in autotrophic respiration under prolonged drought in contrast to measured increases at one of the sites. Secondly, models lacking a phenological response to drought introduced bias in the sensitivity of canopy productivity and respiration to drought. Thirdly, the phenomenological water-stress functions used by the terrestrial biosphere models to represent the effects of soil moisture on stomatal conductance yielded unrealistic diurnal and seasonal responses to drought.

Deforestation and climate feedbacks threaten the ecological integrity of south-southeastern Amazonia.

A mosaic of protected areas, including indigenous lands, sustainable-use production forests and reserves and strictly protected forests is the cornerstone of conservation in the Amazon, with almost 50 per cent of the region now protected. However, recent research indicates that isolation from direct deforestation or degradation may not be sufficient to maintain the ecological integrity of Amazon forests over the next several decades. Large-scale changes in fire and drought regimes occurring as a result of deforestation and greenhouse gas increases may result in forest degradation, regardless of protected status. How severe or widespread these feedbacks will be is uncertain, but the arc of deforestation in south-southeastern Amazonia appears to be particularly vulnerable owing to high current deforestation rates and ecological sensitivity to climate change. Maintaining forest ecosystem integrity may require significant strengthening of forest conservation on private property, which can in part be accomplished by leveraging existing policy mechanisms.