Assessing the costs and benefits of agricultural production using an ecosystem approach

Integrated Farm Management (IFM) is seen as one way for agriculture to contribute towards the UKs challenging national targets for climate change, pollution, biodiversity and other environmental factors. Whilst it is clear that IFM and associated assurance schemes have a role in food quality and enhancement of the environment, they fail to address a number of issues. In particular, they fail to take sufficient account of ‘impact’ and ‘outcome’. In contrast, the relatively new concept of an ecosystem approach does consider these and there is extensive synergy between this approach and IFM. This is pertinent because the UK Department for the Environment, Food and Rural Affairs (Defra) is taking steps to embed an ecosystem approach in policy-making and delivery. This paper sets out to explore the links between IFM and an ecosystem approach and introduces a simple matrix to show how an ecosystem approach might be used to assess the outcome of IFM practices. Limited use of an ecosystem approach suggests that this type of methodology could deliver useful results for IFM. However, it should be used as a decision-support tool rather than a decision-maker. The advantage of using an ecosystem approach for assessing the impact of IFM is that it provides a holistic assessment of land management strategies, rather than focusing on either cropping, or environmental management, alone. However, the values assigned to individual parameters are generally based on expert opinion and, as such, are open to interpretation. Indeed, an ecosystem approach should be interdisciplinary, utilising the knowledge and expertise of a range of stakeholders. Whilst the development of an ecosystem approach for use within an agricultural setting shows promise, it is still in its infancy. There is a need for much discussion, between many disciplines, before it becomes accepted practice

Saliency of Category Information in Person Perception for Ingroup and Outgroup Members

The saliency of category information in person perception for ingroup and outgroup members was investigated. European American participants were presented with a fictional character that varied in race (African American or European American) and occupational garb (military, judge, doctor, or athlete). Occupations were chosen to be either stereotypical or nonstereotypical for African Americans and European Americans with the aid of the Statistical Abstract of the United States (1992) percentages. Based on prior research findings (Park & Rothbart, 1982; Mackie & Worth, 1989), it was predicted European American participants would spontaneously describe an outgroup character by race (superordinate category information), but would mention occupation (subordinate category information) when spontaneously describing the ingroup character. As predicted, results indicated race was rarely mentioned when describing the ingroup character, but was usually the first label applied for the outgroup character. Moreover, when describing the ingroup character, as compared to the outgroup character, occupation was mentioned earlier. Thus, differential utilization of organizing information about a seemingly mundane stimulus may provide a clue as to the origins of intergroup categorizations and bias

Constraints on Radial Migration in Spiral Galaxies - II. Angular momentum distribution and preferential migration

The orbital angular momentum of individual stars in galactic discs can be permanently changed through torques from transient spiral patterns. Interactions at the corotation resonance dominate these changes and have the further property of conserving orbital circularity. We derived in an earlier paper an analytic criterion that an unperturbed stellar orbit must satisfy in order for such an interaction to occur i.e. for it to be in a trapped orbit around corotation. We here use this criterion in an investigation of how the efficiency of induced radial migration for a population of disc stars varies with the angular momentum distribution of that population. We frame our results in terms of the velocity dispersion of the population, this being an easier observable than is the angular momentum distribution. Specifically, we investigate how the fraction of stars in trapped orbits at corotation varies with the velocity dispersion of the population, for a system with an assumed flat rotation curve. Our analytic results agree with the finding from simulations that radial migration is less effective in populations with 'hotter' kinematics. We further quantify the dependence of this trapped fraction on the strength of the spiral pattern, finding a higher trapped fraction for higher amplitude perturbations.Comment: 28 pages, 15 figure, accepted for publication in MNRA