Why, how, and how far should microbiological contamination in a coastal zone be mitigated? An application of the systems approach to the Thau lagoon (France)

Full text : http://archimer.ifremer.fr/doc/00136/24775/22959.pdf (Version "auteur", 0.77 Mo)International audienceThis paper describes the building of an integrated simulation tool based on a systems approach, and its contribution to local political discussion of the mitigation of microbiological contamination of the water in a coastal area. Local management schemes view water quality as a high-priority environmental objective. In practice, how far this objective is achieved depends on trade-offs between the costs of improved water treatment facilities and the acceptable impacts of water contamination. An in-the-field experiment in collaboration with local managers was carried out in the Thau lagoon on the French Mediterranean coast during the SPICOSA (Science and Policy Integration for Coastal System Assessment) project, from 2007 through 2011. It consisted of building a modeling platform and an integrated assessment framework for simulating exploratory scenarios. The modeling platform combines a dynamic contamination model, which represents the sources of microbiological contamination, wastewater treatment facilities, and physical mechanisms of lagoon contamination, with a prospective economic model, which estimates the patterns of development of economic activities in the area through a holistic approach. Exploratory scenarios are used to assess the risk of water contamination and the efficiency of management measures, under various assumptions about the evolution of the system. The contamination simulations suggest that the work currently planned by local authorities will be inadequate for preventing increased water pollution, and that additional but fairly inexpensive management measures for maintaining the current level of water quality should be considered. The integrated assessment framework estimates the ecological and socio-economic impacts of the various pollution mitigation policies in the broader context of possible local development patterns. The results illustrate how the systems approach may aid in the design of an applicable water policy based on operational objectives and feasible technical options. (C) 2013 Elsevier Ltd. All rights reserved

Economic valuation of the vulnerability of world agriculture confronted with pollinator decline

International audienceThere is mounting evidence of pollinator decline all over the world and consequences in many agricultural areas could be significant. We assessed these consequences by measuring 1) the contribution of insect pollination to the world agricultural output economic value, and 2) the vulnerability of world agriculture in the face of pollinator decline. We used a bioeconomic approach, which integrated the production dependence ratio on pollinators, for the 100 crops used directly for human food worldwide as listed by FAO. The total economic value of pollination worldwide amounted to €153 billion, which represented 9.5% of the value of the world agricultural production used for human food in 2005. In terms of welfare, the consumer surplus loss was estimated between €190 and €310 billion based upon average price elasticities of –1.5 to –0.8, respectively. Vegetables and fruits were the leading crop categories in value of insect pollination with about €50 billion each, followed by edible oil crops, stimulants, nuts and spices. The production value of a ton of the crop categories that do not depend on insect pollination averaged €151 while that of those that are pollinator-dependent averaged €761. The vulnerability ratio was calculated for each crop category at the regional and world scales as the ratio between the economic value of pollination and the current total crop value. This ratio varied considerably among crop categories and there was a positive correlation between the rate of vulnerability to pollinators decline of a crop category and its value per production unit. Looking at the capacity to nourish the world population after pollinator loss, the production of 3 crop categories – namely fruits, vegetables, and stimulants– will clearly be below the current consumption level at the world scale and even more so for certain regions like Europe. Yet, although our valuation clearly demonstrates the economic importance of insect pollinators, it cannot be considered as a scenario since it does not take into account the strategic responses of the markets

Des abeilles et des hommes

Selon une phrase attribuée à tort ou à raison à Albert Einstein, « si l’abeille disparaissait de la surface du globe, l’homme n’aurait plus que quatre années à vivre ». Bien qu’aucune source fiable ne confirme son attribution au grand physicien allemand, cette célèbre citation a de quoi faire frémir. Sans doute à juste titre, car le dernier rapport de l’Intergovernmental Panel on Biodiversity and Ecosystem Services (IPBES) a lancé récemment un cri d’alarme qui a renforcé celui de nombreux che..

Of bees and men

According to a sentence rightly or wrongly attributed to Albert Einstein, "if the bee disappeared from the face of the earth, man would only have four more years to live". Although no reliable source has ever confirmed that the quotation was from the major German physicist, it can still make you tremble. And rightly so, the latest Intergovernmental Panel on Biodiversity and Ecosystem Services (IPBES) report has just issued a warning following in the steps of so many researchers: the world po..

Chapitre 3 : La valeur des services offerts par les pollinisateurs

International audienc

Impacts of degraded pollination ecosystem services on global food security and nutrition

International audienceNutrient resource loss in human food due to an ecological shock in terms of the depletion of insect pollination services may become a global concern. Inspired by the international trade theory, we use a bioeconomic model to estimate the impact of crop price changes on nutrient consumption as crop supply and demand vary under different scenarios of pollinators decline. Our findings show that the average global crop price will increase by about 187% if pollinators go extinct at a global scale and worldwide nutrient consumption from crops may decrease in all scenarios studied, exacerbating food insecurity where food shortage already exists. We argue that the consequences of pollinators decline on human well-being is not only a matter of the crop production quantity in exporting countries but also the global demand of nutrients contained in pollinator-dependent crops as their supply decline

Les politiques publiques pour la protection des abeilles

Chapitre 21National audienceLe déclin annoncé des abeilles est le résultat de différents facteurs d'origines humaine et naturelle. Les politiques publiques agissent principalement sur deux facteurs humains : l'utilisation de produits phytosanitaires et l'état et l'évolution des habitats naturels. Ce chapitre est consacré à une discussion autour de ces politiques publiques. Aussi, pour mieux comprendre le rôle des mécanismes d'incitation, nous commencerons par les définir et les détailler. Puis nous analyserons les politiques actuelles existantes pour la protection des abeilles au niveau national et européen principalement sur l'utilisation des produits phytosanitaires et l'utilisation des sols et l'aménagement paysager

Ecological-economic modeling of pollination complexity and pesticide use in agricultural crops

International audienceRecent years have witnessed a substantial decline of both managed and wild bees in Europe due to the increase of pesticides use. Hence, many European agricultural systems depend on the buy/rental of managed bees in order to maintain sufficient levels of pollination services. However, this substitution of wild bees by managed ones apart from costly may be also ineffective as managed bees are not perfect substitutes for wild ones. In fact, a plethora of ecological studies showed that the presence of both bee species in the field and their complementarity effect generates an enhanced pollination activity which optimizes production. This study tries to evaluate this effect by developing an analytical ecological-economic model displaying farmer’s decisions between two agricultural inputs, pollination services and pesticides. Our results highlight that the economic value of this complementarity may offer to farmers an alternative optimum management strategy. This strategy lies on the production range where managed bees are working together with wild ones, offering an enhanced pollination to the crop production. Moreover, we showed that the adoption of a less toxic pesticide or better application methods by the farmers should increase the wild bees’ productivity and consequently, the total economic value of pollinators

Services ecosystémique dans un état équilibre général

International audienceInsect pollination is widely used for agricultural production and contributes significantly to the global value of crops. In this study, the impact of insect pollinators on the social welfare is assessed within a general equilibrium. What would be the general consequences of a production loss due to pollinators decline? How are changes in profits distributed between producers of pollinated goods and other producers? These questions are studied within two alternative distribution of property rights over the firms: the case when agents possess and equal share of the firms (egalitarian ownership structure) and the case where each agent possesses one firm (polarized ownership structure). For each case, we consider the case when agent and firms are homogeneous, and the case when firms are heterogeneous. Under the egalitarian ownership structure, a pollinator decline will result in the decrease of the utility of both agents. When the distribution of the property right is polarized, the utility of the owner of the firm that produces the good which is not pollinator-dependent, will increase. Under specified condition, the social welfare might increase, especially if the production function of the firm of the non dependant sector is more efficient than the other