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Category: 2007

Payments for Ecosystem Services: why precision and targeting matter

Francisco Alpizar, Allen Blackman, Alexander Pfaff
Resources 2007 volume 165:20-22

PDF link iconEven a perfect measure of the ecosystem services provided by each parcel enrolled in a PES program would be insufficient to measure the overall effectiveness of the program. The simple reason is that if a PES program does not lead to an increase in the provision of ecosystem services compared to what would have happened in the absence of the program—that is, the baseline or “counterfactual”—then it has not accomplished anything. Imagine a PES program focused on forest conservation that makes payments to managers of ecologically rich forest land, who have no incentive to clear the land because it is illsuited for logging, agriculture, or urbanization. Payments to these managers would have little impact on deforestation because the risk of clearing was minimal to begin with. In contrast, payments to managers who have incentives to clear their land would be much more likely to have an impact.

 

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Estimating Spatial Interactions in Deforestation Decisions

Juan Robalino, Alexander Pfaff, G. Arturo Sanchez-Azofeifa
Frontiers of Biodiversity Economics, Cambridge University Press

PDF link iconThis chapter is structured as follows. Section 2 describes a simple model of interactions in the context of deforestation, based on an equilibrium in beliefs about the neighbours’ actions. Section 3 discusses empirical issues in measurement of interactions and the benefits of using an instrumental variable approach. Data requirements for analysing neighbours’ interactions in deforestation decisions are discussed in section 4. Finally, results for two regions within Costa Rica, as well as discussion of how to obtain the equilibria once the parameters of the model are estimated, are presented in section 5.

 

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Reduction in Urinary Arsenic Levels in Response to Arsenic Mitigation Efforts in Araihazar, Bangladesh

Yu Chen, Alexander van Geen, Joseph H. Graziano, Alexander Pfaff, Malgosia Madajewicz, Faruque Parvez, A.Z.M Iftehkar Hussain, Vesna Slavkovich, Tariqul Islam, Habibul Ahsan
Environmental Health Perspectives, Vol. 115, No. 6 (Jun., 2007), pp. 917-923

PDF link iconBACKGROUND: There is a need to identify and evaluate an effective mitigation program for arsenic exposure from drinking water in Bangladesh.   OBJECTIVE: We evaluated the effectiveness of a multifaceted mitigation program to reduce As exposure among 11,746 individuals in a prospective cohort study initiated in 2000 in Araihazar, Bangladesh, by interviewing participants and measuring changes in urinary As levels. METHODS: The interventions included  a) person-to-person reporting of well test results and health education; b) well labeling and village-level health education; and c) installations of fifty deep, low-As community wells in villages with the highest As exposure. RESULTS: Two years after these interventions, 58% of the 6,512 participants with unsafe wells (As >=50 micrograms/L) at baseline had responded by switching to other wells. Well labeling and village-level health education was positively related to switching to safe wells (As < 50 micrograms/L) among participants with unsafe wells [rate ratio(RR)= 1.84; 95% confidence interval(CI), 1.60-2.11] and inversely related to any well switching among those with safe wells (RR = 0.80; 95% CI, 0.66-0.98). The urinary As level in participants who switched to a well identified as safe (< 50 micrograms As/L) dropped from an average of 375 micrograms As/g creatinine to 200 micrograms As/g creatinine, a 46% reduction toward the average urinary As content of 136 micrograms As/g creatinine for participants that used safe wells throughout. Urinary As reduction was positively related to educational attainment, body mass index, never-smoking, absence of skin lesions, and time since switching (p for trend< 0.05). CONCLUSIONS: Our   study shows that testing of wells and informing households of the consequences of As exposure, combined with installation of deep community wells where most needed, can effectively address the continuing public health emergency from arsenic in drinking water in Bangladesh.

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