Ecosystem Resilience and Threshold Response in the Galápagos Coastal Zone

Background: The Intergovernmental Panel on Climate Change (IPCC) provides a conservative estimate on rates of sea-level rise of 3.8 mm yr⁻¹ at the end of the 21st century, which may have a detrimental effect on ecologically important mangrove ecosystems. Understanding factors influencing the long-term resilience of these communities is critical but poorly understood. We investigate ecological resilience in a coastal mangrove community from the Galápagos Islands over the last 2700 years using three research questions: What are the 'fast and slow' processes operating in the coastal zone? Is there evidence for a threshold response? How can the past inform us about the resilience of the modern system?Methodology/Principal Findings: Palaeoecological methods (AMS radiocarbon dating, stable carbon isotopes (δ13C)) were used to reconstruct sedimentation rates and ecological change over the past 2,700 years at Diablas lagoon, Isabela, Galápagos. Bulk geochemical analysis was also used to determine local environmental changes, and salinity was reconstructed using a diatom transfer function. Changes in relative sea level (RSL) were estimated using a glacio-isostatic adjustment model. Non-linear behaviour was observed in the Diablas mangrove ecosystem as it responded to increased salinities following exposure to tidal inundations. A negative feedback was observed which enabled the mangrove canopy to accrete vertically, but disturbances may have opened up the canopy and contributed to an erosion of resilience over time. A combination of drier climatic conditions and a slight fall in RSL then resulted in a threshold response, from a mangrove community to a microbial mat.Conclusions/Significance: Palaeoecological records can provide important information on the nature of non-linear behaviour by identifying thresholds within ecological systems, and in outlining responses to 'fast and slow' environmental change between alternative stable states. This study highlights the need to incorporate a long-term ecological perspective when designing strategies for maximizing coastal resilience.</p

Effectiveness of iodine-impregnated incise drapes for preventing surgical site infection in patients with clean or clean contaminated wounds: A systematic literature review and cost-consequence analysis

Background: Surgical site infection is a serious complication associated with significant morbidity, mortality and health care expenditure. Aims: To determine the clinical effectiveness and economic impact of using iodine-impregnated incise drapes for preventing surgical site infection. Methods: MEDLINE, Embase, Cochrane Library and CINAHL databases were systematically searched. Critical appraisal and synthesis of clinical evidence informed a decision analytical cost-consequence model. Findings: Nine studies were included in the systematic literature review. Evidence from cardiac surgery patients was considered appropriate to inform the cost analysis. The economic model evaluation estimated cost savings of £549 per patient with the iodophor-impregnated drape in the deterministic analysis and a mean cost saving per patient of £554,172 per 1000 in the probabilistic analysis. Conclusion: Using iodine-impregnated drapes in cardiac surgery patients may effectively reduce infections and provide cost-savings, but further research is required