Novel insights into Mediterranean forest structure using high-resolution remote sensing.

PhD Theses.Tree crown morphology and arrangement in three-dimensional space is a key driver of forest dynamics, determining not only the competitiveness of an individual but also the competitive effect exerted on neighbouring trees. Many theoretical frameworks aim to predict crown morphology from first principles and assumptions of Euclidean form and ultimately infer whole forest stand structure and dynamics but paucity in data has limited vigorous testing. Tree crowns are also not rigid in form and due to their sessile nature, must morphologically adapt to immediate abiotic and biotic surroundings to enhance survival. The characterisation of tree structure has been limited by the simplicity and associated error of traditional crown measurements. This project uses Terrestrial Laser Scanning data collected from a water limited Mediterranean forest community in Spain to highlight methodological opportunities presented by TLS in understanding forest structure and also the various developments required to extract ecologically meaningful metrics from these data. It then applies these novel metrics to answer questions about how tree crowns scale with size, the effects of competition and how plasticity in shape and arrangement interacts with light capture at the individual and plot scales. Modification to existing code as well as bespoke development were required to segment and calculate individual metrics from trees in this forest type. Accurate measures of crown morphology highlighted allometric scaling deviations from theoretical predictions and intra-specific differences in response to competition, calculated using more representative neighbourhood metrics. Inter-specific differences in crown plasticity and significant effects of size (height) were also evident, along with trade-offs between morphological plasticity and crown size. Light capture was positively affected by plasticity with inter-specific differences highlighting various biomass allocations strategies species undertake to acquire light. At the plot scale, mixed-genus plots intercepted less direct light and were structurally more complex rather than more volume filling

How do we want Satellite Remote Sensing to support biodiversity conservation globally?

Essential Biodiversity Variable, Natural Capital, Biodiversity Indicator and Ecosystem Service are four concepts that underpin the most popular frameworks currently considered for helping to coordinate and structure biodiversity monitoring efforts worldwide. Satellite Remote Sensing (SRS) has considerable potential to inform these initiatives. To date, however, discussions on the role of SRS in supporting these frameworks have mostly evolved independently; tend to be led by different groups; sometimes target slightly different scales; and are likely to reach different audiences. Because of this, there is some confusion among environmental managers and policymakers as to what the potential of SRS is or whether there is prospect in considering and promoting the use of satellite data for biodiversity conservation. 2. Here, we provide a brief overview of the role of SRS to date in informing these frameworks. Through a case study focused on the Sahara Desert ecosystem, we also demonstrate the current potential for SRS-based methodologies to support conservation in data-deficient areas and discuss the relative applicability of SRS-based metrics to each of these frameworks. 3. The relevance and use of SRS across the four frameworks are clearly variable, due to differences and ambiguity in definitions, and due to differences in monitoring priorities. Our case study illustrates the particularly high potential for SRS approaches to provide key information relevant to the Biodiversity Indicators framework in desert ecosystems; it also identifies SRS-based metrics relevant to all frameworks. 4. Altogether, this work highlights how more dialogue is required within the biodiversity-monitoring community for SRS to reach its full potential in conservation. In particular, agreement on what is needed in priority, given the realm of what is possible, will be of paramount importance to developing SRS-based products that are used by policymakers and international conventions

Prospective observational cohort study on grading the severity of postoperative complications in global surgery research

Background The Clavien–Dindo classification is perhaps the most widely used approach for reporting postoperative complications in clinical trials. This system classifies complication severity by the treatment provided. However, it is unclear whether the Clavien–Dindo system can be used internationally in studies across differing healthcare systems in high- (HICs) and low- and middle-income countries (LMICs). Methods This was a secondary analysis of the International Surgical Outcomes Study (ISOS), a prospective observational cohort study of elective surgery in adults. Data collection occurred over a 7-day period. Severity of complications was graded using Clavien–Dindo and the simpler ISOS grading (mild, moderate or severe, based on guided investigator judgement). Severity grading was compared using the intraclass correlation coefficient (ICC). Data are presented as frequencies and ICC values (with 95 per cent c.i.). The analysis was stratified by income status of the country, comparing HICs with LMICs. Results A total of 44 814 patients were recruited from 474 hospitals in 27 countries (19 HICs and 8 LMICs). Some 7508 patients (16·8 per cent) experienced at least one postoperative complication, equivalent to 11 664 complications in total. Using the ISOS classification, 5504 of 11 664 complications (47·2 per cent) were graded as mild, 4244 (36·4 per cent) as moderate and 1916 (16·4 per cent) as severe. Using Clavien–Dindo, 6781 of 11 664 complications (58·1 per cent) were graded as I or II, 1740 (14·9 per cent) as III, 2408 (20·6 per cent) as IV and 735 (6·3 per cent) as V. Agreement between classification systems was poor overall (ICC 0·41, 95 per cent c.i. 0·20 to 0·55), and in LMICs (ICC 0·23, 0·05 to 0·38) and HICs (ICC 0·46, 0·25 to 0·59). Conclusion Caution is recommended when using a treatment approach to grade complications in global surgery studies, as this may introduce bias unintentionally

The surgical safety checklist and patient outcomes after surgery: a prospective observational cohort study, systematic review and meta-analysis

© 2017 British Journal of Anaesthesia Background: The surgical safety checklist is widely used to improve the quality of perioperative care. However, clinicians continue to debate the clinical effectiveness of this tool. Methods: Prospective analysis of data from the International Surgical Outcomes Study (ISOS), an international observational study of elective in-patient surgery, accompanied by a systematic review and meta-analysis of published literature. The exposure was surgical safety checklist use. The primary outcome was in-hospital mortality and the secondary outcome was postoperative complications. In the ISOS cohort, a multivariable multi-level generalized linear model was used to test associations. To further contextualise these findings, we included the results from the ISOS cohort in a meta-analysis. Results are reported as odds ratios (OR) with 95% confidence intervals. Results: We included 44 814 patients from 497 hospitals in 27 countries in the ISOS analysis. There were 40 245 (89.8%) patients exposed to the checklist, whilst 7508 (16.8%) sustained ≥1 postoperative complications and 207 (0.5%) died before hospital discharge. Checklist exposure was associated with reduced mortality [odds ratio (OR) 0.49 (0.32–0.77); P\u3c0.01], but no difference in complication rates [OR 1.02 (0.88–1.19); P=0.75]. In a systematic review, we screened 3732 records and identified 11 eligible studies of 453 292 patients including the ISOS cohort. Checklist exposure was associated with both reduced postoperative mortality [OR 0.75 (0.62–0.92); P\u3c0.01; I2=87%] and reduced complication rates [OR 0.73 (0.61–0.88); P\u3c0.01; I2=89%). Conclusions: Patients exposed to a surgical safety checklist experience better postoperative outcomes, but this could simply reflect wider quality of care in hospitals where checklist use is routine

Critical care admission following elective surgery was not associated with survival benefit: prospective analysis of data from 27 countries

This was an investigator initiated study funded by Nestle Health Sciences through an unrestricted research grant, and by a National Institute for Health Research (UK) Professorship held by RP. The study was sponsored by Queen Mary University of London