Being Able to Stay or Learning to Stay: A Study of Rural Boys’ Educational Orientations and Transitions

This study explores the influence of geographical location on young pupils’ educational orientations and their transition from lower to upper secondary school; it pays particular attention to the voices of male youths from a rural area. More specifically, it investigates the interplay between gender and geographical contexts and the significance of these factors in understanding the processes associated with educational orientations. Margaret Archer’s framework is used to analyse how pupils’ agency is constrained and/or enabled by objective structures. The data material consists of qualitative interviews with 18 pupils transitioning from lower to upper secondary school in Norway. Each of the pupils was interviewed twice: first when they were in their last year of lower secondary education, and then during their first year of upper secondary education. The findings show that pupils consider geographical locations when making decisions about further education and work. In addition, they believe that education beyond compulsory schooling benefits their life in the rural areas. However, unlike their urban counterparts, pupils from rural areas appear to have a more constraining transition to upper secondary education. Through the analyses in this article, it becomes clear that both geographical location and gender are key factors for understanding processes connected to education

Where could catch shares prevent stock collapse?

In a widely received study (Science 321: 1678–1681) Costello and his colleagues found that catch shares give better stock persistence and higher catch for fishermen. The conclusions made by Costello et al were further being supported by Grafton and McIlgrom (Marine Policy 33: 714– 719) where they suggested a framework in order to determine the costs and benefits of separate ITQ management in seven Australian commonwealth fisheries, and what the alternatives should be if the net benefits do not justify ITQs. This raises the question why we do not see catch shares being used more often. We explore at a global scale which countries would have the potential for – and indeed do fulfil the conditions necessary to implement such a management strategy

Optimal age- and gear-specific harvesting policies for North-East Arctic cod

We examine optimal harvest policies in a multi-cohort, multi-gear bioeconomic model of North-East Arctic cod (Gadus morhua) which includes cannibalism and contains broader ecosystem effects. By controlling the selectivity of the different fishing equipment, we can partially target different age cohorts. We show that current gear selectivity implies that the wrong fish are targeted. Optimization shifts the exploitation pattern towards older and heavier fish. This increases the harvested biomass while reducing the number of fish removed from the ocean. The result is a much more robust and abundant cod stock with an age/size distribution closer to the stocks natural state. We optimize the Net Present Value (NPV) generated by the fishery by letting effort and selectivity be the control variables and find that NPV may be more than doubled, even when only gear selectivity or harvest effort is allowed to vary. (141 words

Non-cooperative exploitation of multi-cohort fisheries — the role of gear selectivity in the North-East Arctic cod fishery

North-East Arctic cod is shared by Russia and Norway. Taking its multi-cohort structure into account, how would optimal management look like? How would non-cooperative exploitation limit the obtainable profits? To which extent could the strategic situation explain today’s over- harvesting? Simulation of a detailed bio-economic model reveals that the mesh size should be significantly increased, resulting not only in a doubling of economic gains, but also in a biologi- cally healthier age-structure of the stock. The Nash Equilibrium is close to the current regime. Even when effort is fixed to its optimal level, the non-cooperative choice of gear selectivity leads to a large dissipation of rents

Experimental evidence that livestock grazing intensity affects cyclic vole population regulation processes

Peer reviewedPublisher PD

Leaf economics fundamentals explained by optimality principles

The life span of leaves increases with their mass per unit area (LMA). It is unclear why. Here, we show that this empirical generalization (the foundation of the worldwide leaf economics spectrum) is a consequence of natural selection, maximizing average net carbon gain over the leaf life cycle. Analyzing two large leaf trait datasets, we show that evergreen and deciduous species with diverse construction costs (assumed proportional to LMA) are selected by light, temperature, and growing-season length in different, but predictable, ways. We quantitatively explain the observed divergent latitudinal trends in evergreen and deciduous LMA and show how local distributions of LMA arise by selection under different environmental conditions acting on the species pool. These results illustrate how optimality principles can underpin a new theory for plant geography and terrestrial carbon dynamics

How predation and landscape fragmentation affect vole population dynamics

Background: Microtine species in Fennoscandia display a distinct north-south gradient from regular cycles to stable populations. The gradient has often been attributed to changes in the interactions between microtines and their predators. Although the spatial structure of the environment is known to influence predator-prey dynamics of a wide range of species, it has scarcely been considered in relation to the Fennoscandian gradient. Furthermore, the length of microtine breeding season also displays a north-south gradient. However, little consideration has been given to its role in shaping or generating population cycles. Because these factors covary along the gradient it is difficult to distinguish their effects experimentally in the field. The distinction is here attempted using realistic agent-based modelling. Methodology/Principal Findings: By using a spatially explicit computer simulation model based on behavioural and ecological data from the field vole (Microtus agrestis), we generated a number of repeated time series of vole densities whose mean population size and amplitude were measured. Subsequently, these time series were subjected to statistical autoregressive modelling, to investigate the effects on vole population dynamics of making predators more specialised, of altering the breeding season, and increasing the level of habitat fragmentation. We found that fragmentation as well as the presence of specialist predators are necessary for the occurrence of population cycles. Habitat fragmentation and predator assembly jointly determined cycle length and amplitude. Length of vole breeding season had little impact on the oscillations. Significance: There is good agreement between our results and the experimental work from Fennoscandia, but our results allow distinction of causation that is hard to unravel in field experiments. We hope our results will help understand the reasons for cycle gradients observed in other areas. Our results clearly demonstrate the importance of landscape fragmentation for population cycling and we recommend that the degree of fragmentation be more fully considered in future analyses of vole dynamics