Comment on 'a global map of human impact on marine ecosystems'

Halpern et al. (Reports, 15 February 2008, p. 948) integrated spatial data on 17 drivers of change in the oceans to map the global distribution of human impact. Although fishery catches are a dominant driver, the data reflect activity while impacts occur at different space and time scales. Failure to account for this spatial disconnection could lead to potentially misleading conclusions

Modelling diet composition dynamics among North Sea predatory fish using a length-structured partial ecosystem model

Multispecies fisheries management approaches must take account of the array of trophic interactions within the ecosystem. Studies of the gut contents of fish stocks in the North Sea show decadal changes in diet composition, as might be expected when the relative abundances of prey species change. In this paper we explore the extent to which a simple model of prey consumption deployed within a dynamic multi-species population model is able to capture those changes. We make use of a length-structured partial-ecosystem model (FishSUMS) in which the relative preferences of predators for prey are set by a combination of species weightings and predator-to-prey length ratios. The model allows for diets to evolve over the lifetime of the predator species as well as in response to changes in the available prey. Eleven commercially important North Sea species were included in the model with full length structure, together with other trophic resources represented in less detail. The model was simultaneously tuned to various sources of data, including time series of stock biomass and landings. We show that, despite the simplicity of the representation of the predation process, it is capable of capturing some of the large observed changes in diet in four predator species that were sampled during the Year of the Stomach projects in 1981 and 1991: cod, haddock, whiting and saithe. We also quantify how much of the biomass is lost to the fishery, to predation by explicitly-modelled species, and to unspecified mortality

Global sensitivity analysis of an end-to-end marine ecosystem model of the North Sea : factors affecting the biomass of fish and benthos

Comprehensive analysis of parameter and driver sensitivity is key to establishing the credibility of models of complex systems. This is especially so for models of natural systems where experimental manipulation of the real-world to provide controlled validation data is not possible. Models of marine ecosystems fall into this category, but despite the interest in these models for evaluating the effects of climate change and fishing on nutrient fluxes and the abundances of flora and fauna, none have yet been subjected to global sensitivity analysis. Here we present results of both local ‘one-at-a-time’ (OAT), and variance based global sensitivity analyses (GSA) of the fish and fishery aspects of StrathE2E, an end-to-end (nutrients to birds and mammals) ecosystem model of the North Sea. The sensitivity of the model was examined with respect to internal biological parameters, and external drivers related to climate and human activity. The OAT Morris method was first used to screen for factors most influential on model outputs. The Sobol GSA method was then used to calculate quantitative sensitivity indices. The results indicated that the fish and shellfish components of the model (demersal and pelagic fish, filter/deposit and scavenge/carnivore feeding benthos) were influenced by different sets of factors. Harvesting rates were directly influential on demersal and pelagic fish biomasses. Suspension/deposit feeding benthos were directly sensitive to changes in temperature, while the temperature acted indirectly on pelagic fish through the connectivity between model components of the food web. Biomass conversion efficiency was the most important factor for scavenge/carnivorous feeding benthos. The results indicate the primacy of fishing as the most important process affecting total fish biomass, together with varying responses to environmental factors which may be relevant in the context of climate change. The non-linear responses and parameter interactions identified by the analysis also highlight the necessity to use global rather than local methods for the sensitivity analysis of ecosystem models

Blending single beam RoxAnn and multi-beam swathe QTC hydro-acoustic discrimination techniques for the Stonehaven area, Scotland, UK

Surface properties of the seabed in a 180 km2 area of coastal waters (14-57 m depth) off northeast Scotland were mapped by hydro-acoustic discrimination using single and multi-beam echosounders linked to signal processing systems (RoxAnn for the single beam, and Questor Tangent Corporation (QTC) Multiview for the multibeam). Subsequently, two ground truthing surveys were carried out, using grab and TV sampling. The RoxAnn and QTC-Multiview outputs showed strong similarity in their classifications of seabed types. Classifications generated by QTC-Multiview were used to supervise those based on seabed roughness and hardness indices produced by the RoxAnn system and thereby develop a ‘blended’ map based on both systems. The resulting hydro-acoustic classes agreed well with a cluster analysis of data on sediment grain sizes from the grab sampling, and indicated that the area could be described by distinct regions of surface texture and surficial sediments ranging from muddy sand to boulders and rock

Ecosystem limits to food web fluxes and fisheries yields in the North Sea simulated with an end-to-end food web model

Equilibrium yields from an exploited fish stock represent the surplus production remaining after accounting for losses due to predation. However, most estimates of maximum sustainable yield, upon which fisheries management targets are partly based, assume that productivity and predation rates are constant in time or at least stationary. This means that there is no recognition of the potential for interaction between different fishing sectors. Here, an end-to-end ecosystem model is developed to explore the possible scale and mechanisms of interactions between pelagic and demersal fishing in the North Sea. The model simulates fluxes of nitrogen between detritus, inorganic nutrient and guilds of taxa spanning phytoplankton to mammals. The structure strikes a balance between graininess in space, taxonomy and demography, and the need to constrain the parameter-count sufficiently to enable automatic parameter optimization. Simulated annealing is used to locate the maximum likelihood parameter set, given the model structure and a suite of observations of annual rates of production and fluxes between guilds. Simulations of the impact of fishery harvesting rates showed that equilibrium yields of pelagic and demersal fish were strongly interrelated due to a variety of top-down and bottom-up food web interactions. The results clearly show that management goals based on simultaneously achieving maximum sustainable biomass yields from all commercial fish stocks is simply unattainable. Trade-offs between, for example, pelagic and demersal fishery sectors and other properties of the ecosystem have to be considered in devising an overall harvesting strategy

A view from above : changing seas, seabirds and food sources

In this review we summarize what is known about mechanisms by which climate change may be affecting the populations of seabirds around the UK. Breeding success and adult survival are the key factors affecting changes in seabird populations, and food intake is implicated as a major determinant of both. The diet of most UK seabird species is almost exclusively sandeels, small clupeoid fish or zooplankton and it is clear that the marine pelagic food web is the key ecological system determining food supply. Hence, we develop the review by first considering how climate changes may affect primary production, and then examine how this propagates through the food web to zooplankton and fish culminating in fluctuations in seabird numbers. A trend of increasing numbers of many seabird species since 1970, particularly puffins, guillemots and razorbills, appears to have been reversed since 2000. The proximate cause of the recent declines seems to be a succession of 5 years of low breeding success for a range of species due to a shortage of food, especially sandeels. However, the connection with climate change remains uncertain, though there are indications that declines in the productivity of sandeel populations may be linked in some complex way to warming sea temperatures. The main conclusion is that no part of the marine food web, including fisheries, can be considered in isolation when trying to understand and predict the consequences of climate change for seabirds. Impacts can be expected in all parts of the system, and all parts of the system are interconnected

Charles Taylor as a Christian thinker

This thesis is a critical examination of Charles Taylor's moral theory. Its purpose is to understand both Taylor himself as an important contemporary Christian thinker, as well as the ramifications his philosophy has in the realm of Christian Ethics and Practical Theology.Part I (chapters 1-3) discusses the development of Taylor's moral theory, particularly as it appears in Sources of the Self. Chapter One begins by discussing Taylor's definition of ethics which includes notions of the good and the meaningful in our lives. This leads to his argument that the moral domain depends upon frameworks of significance closely linked to the identity of the moral agent. Chapter Two examines Taylor's idea of moral frameworks in terms of practical reasoning and moral articulation. Finally, Chapter Three develops Taylor's arguments for articulating the goods in our lives, and why this is essential for the pursuit of ethics.Part II (chapters 4-5) investigates certain theological influences on Taylor. Chapter Four is a discussion of Taylor and Augustine which draws certain parallels and contrasts in the field of theological anthropology. Chapter Five examines how Taylor's idea of the Church in modernity has largely been shaped by Yves Congar's writings on the laity and Henry de Lubac's Catholicism. It examines Taylor's ecclesiology with specific reference to these two theologians who have had a significant impact on his Christian identity.Part III (Chapters 6-8) looks more specifically at Taylor's relevancy to Christian Ethics and Practical Theology. By way of introduction, Chapter Six argues for a distinct role for God in Taylor's theory. Following on from this I discuss through a brief historical argument how secular philosophy has eclipsed two important features of Christian Ethics which Taylor asserts are indispensable for giving the best account of the human moral domain. These two features are transcendence and ontology, and Chapter Seven examines these particularly in relation to the role they have in Taylor's philosophy, and what implications this has for Christian Ethics. The final chapter develops the discussion of transcendence and ontology through the essential good of Agape. Agape is discussed not only as a pivotal concept in Christian Ethics, but also as a fundamental part of Taylor's own moral framework. I conclude this chapter by arguing that Taylor's ontologically 'thick' concept of Agape as an empowering good needs to be considered in Christian Ethics if we are to be consistent about the transcendent and ontological claims of the discipline.In conclusion I bring together some of the seminal features of Taylor's philosophy as articulated in the thesis. In particular these are discussed in the light of their valuable contribution to our understanding of Christian Ethics and Practical Theolog

Discerning and Developing Department Chairs as Instructional Leaders: A Case Study of a Large Suburban High School

Prevailing research on instructional leadership has primarily focused on school administration to fulfill this role. Growing accountability from state officials, increased departmentalization, and demands on administrations’ time and resources led to the need to study other avenues of leadership in secondary schools. In this qualitative case study, the researcher looked at the current perceptions and beliefs of administration, department chairs, and teachers concerning the department chair role. An understanding of department chairs’ instructional leadership capacity, distributed leadership in the school of study, and collective efficacy were investigated to determine the best ways to employ department chairs to support teacher development while impacting student performance. Interviews of administrators, department chairs, and teachers were solicited to provide their perceptions and beliefs regarding the position of department chair through the lens of instructional leadership. Similarities and differences were collected to develop descriptive themes designed to encompass department chair characteristics currently present in the school of study. The study findings indicated continuity in some aspects of the role of department chair while highlighting disparities between perceived and substantive characteristics. The major themes of collaboration, trust, traditional management, advocacy, mentorship, growth mindset, instruction, and distributed leadership were found throughout the participants’ responses. Perceptions and beliefs of how each group observed these themes regarding the research questions illustrated areas of inconsistencies for future analysis and study. As a consequence, a clearly defined job description and training program for the position of department chair and other lower-level positions such as professional learning community leads need to be considered to provide more opportunity for the role of departments to develop their instructional leadership capacity, to enhance teacher growth, and to increase student success. iv Keywords: administrators, collective efficacy, department chairs, distributed leadership, instructional leadershi

Exploring Health Information Exchange (HIE) Through Collaboration Framework: Normative Guidelines for IT Leadership of Healthcare Organizations

Health Information Exchanges (HIEs) hold the promise to integrate patient data residing across disparate information systems in various hospitals to improve care coordination, patient engagement, and provisioning of real-time information to physicians. This research posits that collaboration is the key to HIE’s success. Drawing from the extant literature on collaboration, we discuss collaboration-related challenges that healthcare IT leaders are facing and provide normative guidelines that they can implement during the HIE initiation phase as well as the maintenance phas