Disentangling trophic interactions inside a Caribbean marine reserve

Author Posting. © Ecological Society of America, 2010. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecological Applications 20 (2010): 1979–1992, doi:10.1890/09-1217.1.Recent empirical studies have demonstrated that human activities such as fishing can strongly affect the natural capital and services provided by tropical seascapes. However, policies to mitigate anthropogenic impacts can also alter food web structure and interactions, regardless of whether the regulations are aimed at single or multiple species, with possible unexpected consequences for the ecosystems and their associated services. Complex community response to management interventions have been highlighted in the Caribbean, where, contrary to predictions from linear food chain models, a reduction in fishing intensity through the establishment of a marine reserve has led to greater biomass of herbivorous fish inside the reserve, despite an increased abundance of large predatory piscivores. This positive multi-trophic response, where both predators and prey benefit from protection, highlights the need to take an integrated approach that considers how numerous factors control species coexistence in both fished and unfished systems. In order to understand these complex relationships, we developed a general model to examine the trade-offs between fishing pressure and trophic control on reef fish communities, including an exploration of top-down and bottom-up effects. We then validated the general model predictions by parameterizing the model for a reef system in the Bahamas in order to tease apart the wide range of species responses to reserves in the Caribbean. Combining the development of general theory and site-specific models parameterized with field data reveals the underlying driving forces in these communities and enables us to make better predictions about possible population and community responses to different management schemes.This work was supported by funding from the Bahamas Biocomplexity Project (U.S. NSF Biocomplexity grant OCE-0119976) and U.S. EPA Science to Achieve Results (R832223)

Energy densities of key prey species in the California Current Ecosystem

The energetic content of primary and secondary consumers is central to understanding ecosystem functioning, community assembly, and trophodynamics. However, these foundational data are often limited, especially for marine ecosystems. Here we report the energy densities of important prey species in the California Current Ecosystem. We investigated variation in energy density within and between species and explored potential underlying causes of these differences. Northern anchovy (Engraulis mordax) is the most energy dense of the species analyzed with a median value nearly twice as high as was found in krill (Euphausia pacifica and Thysanoessa spinifera). Relationships with body size varied among species; krill energy density increased, with both length and wet weight. In addition, we find that anchovy, sardine (Sardinops sagax), and market squid (Doryteuthis opalescens) have higher energy content in the summer and fall as compared to the spring. This aligns with the ecosystem phenology of strong upwelling during spring (March – May) driving high primary productivity, followed by widespread predator presence through the summer and fall (June – October). Our results inform food web studies in the California Current and suggest new avenues for investigating differences in species and ecosystem energetics in an era of rapid global change

Resilience of marine ecosystems to climatic disturbances

The intensity and frequency of climate-driven disturbances are increasing in coastal marine ecosystems. Understanding the factors that enhance or inhibit ecosystem resilience to climatic disturbance is essential. We surveyed 97 experts in six major coastal biogenic ecosystem types to identify “bright spots” of resilience in the face of climate change. We also evaluated literature that was recommended by the experts that addresses the responses of habitat-forming species to climatic disturbance. Resilience was commonly reported in the expert surveys (80% of experts). Resilience was observed in all ecosystem types and at multiple locations worldwide. The experts and literature cited remaining biogenic habitat, recruitment/connectivity, physical setting, and management of local-scale stressors as most important for resilience. These findings suggest that coastal ecosystems may still hold great potential to persist in the face of climate change and that local- to regional-scale management can help buffer global climatic impacts

Climate change implications for tidal marshes and food web linkages to estuarine and coastal nekton

Climate change is altering naturally fluctuating environmental conditions in coastal and estuarine ecosystems across the globe. Departures from long-term averages and ranges of environmental variables are increasingly being observed as directional changes [e.g., rising sea levels, sea surface temperatures (SST)] and less predictable periodic cycles (e.g., Atlantic or Pacific decadal oscillations) and extremes (e.g., coastal flooding, marine heatwaves). Quantifying the short- and long-term impacts of climate change on tidal marsh seascape structure and function for nekton is a critical step toward fisheries conservation and management. The multiple stressor framework provides a promising approach for advancing integrative, cross-disciplinary research on tidal marshes and food web dynamics. It can be used to quantify climate change effects on and interactions between coastal oceans (e.g., SST, ocean currents, waves) and watersheds (e.g., precipitation, river flows), tidal marsh geomorphology (e.g., vegetation structure, elevation capital, sedimentation), and estuarine and coastal nekton (e.g., species distributions, life history adaptations, predator-prey dynamics). However, disentangling the cumulative impacts of multiple interacting stressors on tidal marshes, whether the effects are additive, synergistic, or antagonistic, and the time scales at which they occur, poses a significant research challenge. This perspective highlights the key physical and ecological processes affecting tidal marshes, with an emphasis on the trophic linkages between marsh production and estuarine and coastal nekton, recommended for consideration in future climate change studies. Such studies are urgently needed to understand climate change effects on tidal marshes now and into the future

Diversity and ethics in trauma and acute care surgery teams: results from an international survey

Background Investigating the context of trauma and acute care surgery, the article aims at understanding the factors that can enhance some ethical aspects, namely the importance of patient consent, the perceptiveness of the ethical role of the trauma leader, and the perceived importance of ethics as an educational subject. Methods The article employs an international questionnaire promoted by the World Society of Emergency Surgery. Results Through the analysis of 402 fully filled questionnaires by surgeons from 72 different countries, the three main ethical topics are investigated through the lens of gender, membership of an academic or non-academic institution, an official trauma team, and a diverse group. In general terms, results highlight greater attention paid by surgeons belonging to academic institutions, official trauma teams, and diverse groups. Conclusions Our results underline that some organizational factors (e.g., the fact that the team belongs to a university context or is more diverse) might lead to the development of a higher sensibility on ethical matters. Embracing cultural diversity forces trauma teams to deal with different mindsets. Organizations should, therefore, consider those elements in defining their organizational procedures. Level of evidence Trauma and acute care teams work under tremendous pressure and complex circumstances, with their members needing to make ethical decisions quickly. The international survey allowed to shed light on how team assembly decisions might represent an opportunity to coordinate team member actions and increase performance

Interactive effects of urea and lipid content confound stable isotope analysis in elasmobranch fishes

Stable isotope analysis (SIA) is becoming a commonly used tool to study the ecology of elasmobranchs. However, the retention of urea by elasmobranchs for osmoregulatory purposes may bias the analysis and interpretation of SIA data. We examined the effects of removing urea and lipid on the stable isotope composition of fourteen species of sharks, skates, and rays from the eastern North Pacific Ocean. While effects were variable across taxa, removal of urea generally increased δThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Appendix B. Caribbean trophic model parameter estimates.

Caribbean trophic model parameter estimates

Appendix A. Extended sensitivity analysis of the general multi-trophic fisheries model.

Extended sensitivity analysis of the general multi-trophic fisheries model