Publications des chercheurs de PSE

Ce chapitre traite de deux enjeux majeurs auxquels sont confrontés les ménages ruraux en zone tropicale : préserver les ressources naturelles et assurer la sécurité alimentaire. Relever ces deux défis simultanément requiert de développer des systèmes de production efficaces, capables à la fois de garantir la sécurité alimentaire des agriculteurs et d’assurer une gestion durable des ressources naturelles. Pour ce faire, il convient de s’interroger sur les liens directs et indirects entre la sécurité alimentaire des ménages et la biodiversité à l’échelle de l’exploitation agricole et à celle du paysage.

Les groupements d’usagers de la forêt ont contribué à la restauration des forêts au Népal.Les groupements densifient les forêts et en augmentent légèrement la surface.En plus de mieux gérer la forêt, ils modifient les choix énergétiques des ménages.

The objective of this chapter is to collect insights from different sources and different people about institutional features that may slow down economic development in Tanzania or threaten its sustainability and inclusiveness. It essentially follows three approaches presented in three separate sections. First, by exploiting the numerous institutional indicators available in international databases, insights are collected about the quality of Tanzanian institutions in comparison with a set of relevant countries. Insights aim to identify those institutional features that may possibly differentiate Tanzania. Second, an original questionnaire survey is undertaken among various types of decision-makers operating in Tanzania. The survey asks them about their own perception of how institutions work there and how they affect development. Finally, the analysis is enriched by the summary of the main points that arose in a large set of open-ended interviews with top policymakers of the country about the same questions. The final section concludes.

Since 1993, Nepal has implemented one of the most ambitious and comprehensive program of decentralization of forest management in the world, which is widely considered a success story in terms of participatory management of natural resources. Using quasi-experimental methods, we first quantify the net gains in tree cover related to the program in the Hills and Mountains of Nepal, and describe their temporal evolution. We then discuss the mechanisms driving forest restoration, highlighting that, while community forestry played a role in increasing forest biomass and forest size, it also reduced demand pressures by altering energy choices.

This chapter deals with two major issues rural households face in tropical areas: preserving natural resources and guaranteeing food security. Tackling these two challenges simultaneously may require developing profitable production systems that can both guarantee food security for farmers, while also ensuring sustainable management of natural resources.

This paper presents an analytical framework to help understand why some communities successfully manage their renewable natural resources and some fail to do so. We develop a finite-number-of-player, two-period non-cooperative game, where a community can impose an exogenous amount of sanctions. The model develops a nuanced view on Ostrom’s conjecture, stating that, in a common-pool resource it is easier to solve the within-period distributional issue than the between-period conservation problem. We first show that rules preventing dynamic inefficiencies may exist even though static inefficiencies still remain. Second, we show an increase in the initial value of the resource may lower the utility of all users when enforcement mechanisms are bounded. Third, we show that inequalities decrease static inefficiencies but increase dynamic ones.

We investigate the relation between economic growth, household firewood collection and forest conditions in Nepal between 2003 and 2010. Co-movements in these are examined at the household and village levels, combining satellite imagery and household (Nepal Living Standard Measurement Survey) data. Projections of the impact of economic growth based on Engel curves turn out to be highly inaccurate: forest conditions remained stable despite considerable growth in household consumption and income. Firewood collections at the village level remained stable, as effects of demographic growth were offset by substantial reductions in per-household collections. Households substituted firewood by alternative energy sources, particularly when livestock and farm based occupations declined in importance. Engel curve specifications which include household productive assets (a proxy for occupational patterns) provide more accurate predictions. Hence structural changes accompanying economic growth play an important role in offsetting adverse environmental consequences of growth.

Population control policies keep attracting attention: by increasing the household size, having more children would directly contribute to a household’s poverty. Using nationally representative household level data from Nepal, we investigate the links between a household’s fertility decisions and variations in their size and composition. We show that the relationship between number of births and household size is positive when the mothers are young, but becomes negative as the mothers grow older. Elderly couples who had fewer children host, on average, more relatives who are outside the immediate family unit. This result sheds light on the heterogeneous relation between the number of children and household size over the life cycle. It also implies that reductions in a household’s fertility may have an ambiguous impact on its per capita consumption, which depends on how the household’s composition responds to new births and changes over time: in this sample, an old household’s per capita consumption is not affected by the number of births. We use the gender of the first-born child to instrument the total number of consecutive children.

Population control policies keep attracting attention: by increasing the household size, having more children would directly contribute to a household’s poverty. Using nationally representative household level data from Nepal, we investigate the links between a household’s fertility decisions and variations in their size and composition. We show that the relationship between number of births and household size is positive when the mothers are young, but becomes negative as the mothers grow older. Elderly couples who had fewer children host, on average, more relatives who are outside the immediate family unit. This result sheds light on the heterogeneous relation between the number of children and household size over the life cycle. It also implies that reductions in a household’s fertility may have an ambiguous impact on its per capita consumption, which depends on how the household’s composition responds to new births and changes over time: in this sample, an old household’s per capita consumption is not affected by the number of births. We use the gender of the first-born child to instrument the total number of consecutive children.