Crisis or opportunity? Economic degrowth for social equity and ecological sustainability. Introduction to this special issue

This article reviews the burgeoning emerging literature on sustainable degrowth. This is defined as an equitable downscaling of production and consumption that increases human well-being and enhances ecological conditions at the local and global level, in the short and long term. The paradigmatic propositions of degrowth are that economic growth is not sustainable and that human progress without economic growth is possible. Degrowth proponents come from diverse origins. Some are critics of market globalization, new technologies or the imposition of western models of development in the rest of the world. All criticize GDP accounting though they propose often different social and ecological indicators. Degrowth theorists and practitioners support an extension of human relations instead of market relations, demand a deepening of democracy, defend ecosystems, and propose a more equal distribution of wealth. We distinguish between depression, i.e. unplanned degrowth within a growth regime, and sustainable degrowth, a voluntary, smooth and equitable transition to a regime of lower production and consumption. The question we ask is how positive would degrowth be if instead of being imposed by an economic crisis, it would actually be a democratic collective decision, a project with the ambition of getting closer to ecological sustainability and socio-environmental justice worldwide.Most articles in this issue were originally presented at the April 2008 conference in Paris on Economic Degrowth for Ecological Sustainability and Social Equity. This conference brought the word degrowth and the concepts around it into an international academic setting. Articles of this special issue are summarized in this introductory article. Hueting, d'Alessandro and colleagues, van den Bergh, Kerschner, Spangenberg and Alcott discuss whether current growth patterns are (un)sustainable and offer different perspectives on what degrowth might mean, and whether and under what conditions it might be desirable. Matthey and Hamilton focus on social dynamics and the obstacles and opportunities for voluntary social action towards degrowth. Lietaert and Cattaneo with Gavaldà offer a down-to-earth empirical discussion of two practical living experiments: cohousing and squats, highlighting the obstacles for scaling up such alternatives. Finally van Griethuysen explains why growth is an imperative in modern market economies, raising also the question whether degrowth is possible without radical institutional changes.     

A two-dimensional simulation model of phosphorus uptake including crop growth and P-response

Modelling nutrient uptake by crops implies considering and integrating the processes controlling the soil nutrient supply, the uptake by the root system and relationships between the crop growth response and the amount of nutrient absorbed. We developed a model that integrates both dynamics of maize growth and phosphorus (P) uptake. The crop part of the model was derived from Monteith's model. A complete regulation of P-uptake by the roots according to crop P-demand and soil P-supply was assumed. The soil P-supply to the roots was calculated using a diffusion equation and assuming that roots behave as zero-sinks. The actual P-uptake and crop growth were calculated at each time step by comparing phosphate and carbohydrate supply–demand ratios. Model calculations for P-uptake and crop growth were compared to field measurements on a long term P-fertilization trial. Three P-fertilization regimes (no P-fertilization, 42.8 kg P ha⁻¹ year⁻¹ and 94.3 kg P ha⁻¹ year⁻¹) have led to a range of P-supply. Our model correctly simulated both the crop development and growth for all P-treatments. P-uptake was correctly predicted for the two non-limiting P-treatments. Nevertheless, for the limiting P-treatment, P-uptake was correctly predicted during the early period of growth but it was underestimated at the last sampling date (61 day after sowing). Several arguments for under-prediction were considered. However, most of them cannot explain the observed magnitude in discrepancy. The most likely reason might be the fact that biomass allocation between shoot and root must be modelled more precisely. Despite this mismatch, the model appears to provide realistic simulations of the soil–plant dynamic of P in field conditions.     

Spectrum of selection: new approaches to detecting the scale-dependent response to habitat

Detecting habitat selection depends on the spatial scale of analysis, but multi-scale studies have been limited by the use of a few, spatially variable, hierarchical levels. We developed spatially explicit approaches to quantify selection along a continuum of scales using spatial (coarse-graining) and geostatistical (variogram) pattern analyses at multiple levels of habitat use (seasonal range, travel routes, feeding areas, and microsites). We illustrate these continuum-based approaches by applying them to winter habitat selection by woodland caribou (Rangifer tarandus caribou) using two key habitat components, Cladina lichens and snow depth. We quantified selection as the reduction in variance in used relative to available sites, thus avoiding reliance on correlations between organism and habitat, for which interpretation can be impeded by cross-scale correlations. By consistently selecting favorable habitat features, caribou experienced reduced variance in these features. The degree to which selection was accounted for by the travel route, feeding area, or microsite levels varied across the scale continuum. Caribou selected for Cladina within a 13-km scale domain and selected shallower snow at all scales. Caribou responded most strongly at the dominant scales of patchiness, implicating habitat heterogeneity as an underlying cause of multi-scale habitat selection. These novel approaches enable a spatial understanding of resource selection behavior.