Cash for carbon: A randomized trial of payments for ecosystem services to reduce deforestation

Does REDD+ have a chance? Implications from Pemba, Tanzania

Conservation scientists continue to debate the strengths and weaknesses of REDD+ as an instrument to slow greenhouse gas emissions in the developing world. We propose that general positions on this debate are less helpful than drawing lessons from specific investigations into the features of individual projects that make them successful or not. Here, focusing on a site-specific REDD+ intervention in Pemba, Zanzibar (Tanzania), we examine the circumstances under which REDD+ has a chance of success, teasing out specific features of both REDD+ interventions and the socio-economic and institutional contexts that render REDD+ a potentially valuable complement to community forestry. Additionally, we highlight some unanticipated positive outcomes associated with the design features of REDD+ projects. Our broader goal is to move away from ideologically-driven debate to empirically-based identification of general conditions where REDD+ could work, and to provide policy recommendations.

Vegetation Changes Attributable to Refugees in Africa Coincide with Agricultural Deforestation

The recent adoption of the Global Compact on Refugees formally recognizes not only the importance of supporting the nearly 26 million people who have sought asylum from conflict and persecution but also of easing the pressures on receiving areas and host countries. However, few countries may enforce the Compact out of concern over the economic or environmental repercussions of hosting refugees. We examine whether narratives of refugee-driven landscape change are empirically generalizable to continental Africa, which fosters 34% of all refugees. Estimates of the causal effects of the number of refugees-located in 493 camps distributed across 49 African countries-on vegetation from 2000 to 2016 are provided. Using a quasi-experimental design, we find refugees bear a small increase in vegetation condition while contributing to increased deforestation. Such a combination is mainly explained not by land clearance and massive biomass extraction but by agricultural expansion in refugee-hosting areas. A one percent increase in the number of refugees amplifies the transition from dominant forested areas to cropland by 1.4 percentage points. These findings suggest that changes in vegetation condition may ensue with the elevation of population-based constraints on food security.

Did Government Expenditure on the Grain for Green Project Help the Forest Carbon Sequestration Increase in Yunnan, China?

Reasonably assessing the effectiveness of government expenditure on the Grain for Green project (GFG) in providing forest carbon sequestration would contribute to the development of China’s forest carbon sequestration. Using the government expenditure data from the GFG in Yunnan Province from 2001 to 2015 and the MODIS Land Cover Type (MCD12Q1) time-series datasets, we calculated the forest carbon sequestration of various counties (cities or districts). The impacts of GFG government expenditure on forest carbon sequestration were empirically evaluated by the least squares dummy variables method (LSDV). The research results indicate that a 1% increase in government expenditure on the GFG yielded a 0.0364% increase in forest carbon sequestration. However, the effects of GFG government expenditure on forest carbon sequestration differed greatly in different areas because of the diversity of the natural environments, forest resource endowment, and government policies. If the initial forest endowment was not considered, the effectiveness of government expenditure on the GFG in providing forest carbon sequestration would have been overestimated. This study argues that, to improve the efficiency of GFG government expenditure in Yunnan Province, more investment should be made in regions with positive regression coefficients that have passed the significance t-test, such as Diqing Tibetan Autonomous Prefecture in the northwest, Baoshan City in the west, Honghe Hani and Yi Autonomous Prefecture in the south, and Wenshan Zhuang and Miao Autonomous Prefecture in the east.

National mitigation potential from natural climate solutions in the tropics

Better land stewardship is needed to achieve the Paris Agreement's temperature goal, particularly in the tropics, where greenhouse gas emissions from the destruction of ecosystems are largest, and where the potential for additional land carbon storage is greatest. As countries enhance their nationally determined contributions (NDCs) to the Paris Agreement, confusion persists about the potential contribution of better land stewardship to meeting the Agreement's goal to hold global warming below 2°C. We assess cost-effective tropical country-level potential of natural climate solutions (NCS)—protection, improved management and restoration of ecosystems—to deliver climate mitigation linked with sustainable development goals (SDGs). We identify groups of countries with distinctive NCS portfolios, and we explore factors (governance, financial capacity) influencing the feasibility of unlocking national NCS potential. Cost-effective tropical NCS offers globally significant climate mitigation in the coming decades (6.56 Pg CO₂e yr⁻¹ at less than 100 US$ per Mg CO₂e). In half of the tropical countries, cost-effective NCS could mitigate over half of national emissions. In more than a quarter of tropical countries, cost-effective NCS potential is greater than national emissions. We identify countries where, with international financing and political will, NCS can cost-effectively deliver the majority of enhanced NDCs while transforming national economies and contributing to SDGs.

This article is part of the theme issue ‘Climate change and ecosystems: threats, opportunities and solutions’.

Adding rewards to regulation: The impacts of watershed conservation on land cover and household wellbeing in Moyobamba, Peru

We estimate the effects of Peru’s oldest watershed payments for environmental services (PES) initiative in Moyobamba (Andes–Amazon transition zone) and disentangle the complex intervention into its two main forest conservation treatments. First, a state-managed protected area (PA) was established, allowing sustainable use but drastically limiting de facto land use and land rights of households in the upper watershed through command-and-control interventions. Second, a subset of those environmentally regulated households also received incentives: PES-like voluntary contracts with conditional in-kind rewards, combined with access to participation in sustainable income-generating activities of the integrated conservation and development project (ICDP) type. To evaluate impacts, we perform matching procedures and adjustment regressions to obtain the average treatment effect on the treated (ATT) of each intervention. We investigate impacts on plot-level forest cover and household welfare for the period 2010–2016. We find that both treatments—command-and-control restrictions and the incentive package—modestly but significantly mitigated primary forest loss. Incentive-induced conservation gains came at elevated per-hectare implementation costs. We also find positive effects on incentive-treated households’ incomes and assets; however, their self-perceived wellbeing counterintuitively declined. We hypothesise that locally frustrated beneficiary expectations vis-a-vis the ambitiously designed PES-cum-ICDP intervention help explain this surprising finding. We finalise with some recommendations for watershed incentives and policy mix design in Moyobamba and beyond.

What role should randomized control trials play in providing the evidence base for conservation?

The effectiveness of many widely used conservation interventions is poorly understood because of a lack of high-quality impact evaluations. Randomized control trials (RCTs), in which experimental units are randomly allocated to treatment or control groups, offer an intuitive way to calculate the impact of an intervention by establishing a reliable counterfactual scenario. As many conservation interventions depend on changing people's behaviour, conservation impact evaluation can learn a great deal from RCTs in fields such as development economics, where RCTs have become widely used but are controversial. We build on relevant literature from other fields to discuss how RCTs, despite their potential, are just one of a number of ways to evaluate impact, are not feasible in all circumstances, and how factors such as spillover between units and behavioural effects must be considered in their design. We offer guidance and a set of criteria for deciding when RCTs may be an appropriate approach for evaluating conservation interventions, and factors to consider to ensure an RCT is of high quality. We illustrate this with examples from one of the few concluded RCTs of a large-scale conservation intervention: an incentive-based conservation programme in the Bolivian Andes. We argue that conservation should aim to avoid a rerun of the polarized debate surrounding the use of RCTs in other fields. Randomized control trials will not be feasible or appropriate in many circumstances, but if used carefully they can be useful and could become a more widely used tool for the evaluation of conservation impact.

Supply–Demand Coupling Mechanisms for Policy Design

Ecosystem services are important for sustaining human survival and sustainable socio-economic development. For the past two decades, ecosystem services studies have greatly promoted the application of ecosystem services science in conservation. As a scientific method to integrate multi-regional and multi-scale ecosystem service providers and beneficiaries, ecosystem service supply and demand coupling mechanisms and payments for ecosystem services programs are closely linked. In this paper, we first provide an overview of the payments for ecosystem services concept and an evaluation of its effectiveness in implementation. We then analyze the correlation between payments for ecosystem services and supply–demand coupling mechanisms and propose a framework to link these two ideas. China’s practice in implementing ecological redline policy and institutional reforms for protected area management will provide a good experimental platform for comprehensive payments for ecosystem service design and effectiveness evaluation within China and beyond.

Socioeconomic Impacts of the Billion Trees Afforestation Program in Khyber Pakhtunkhwa Province (KPK), Pakistan

In recent decades, the terrestrial ecosystem in Khyber Pakhtunkhwa Province (KPK), Pakistan, has undergone tremendous destruction. To restore environmental conditions, the government implemented the Billion Tree Afforestation Program (BTAP), with a high target to impact multidimensional aspects of the terrestrial ecosystem. The government claims that it is local residents who have benefited the most from the BTAP. Hence, the objective of this research was to examine the socioeconomic impact and local rural perception of the BTAP in three districts of KPK. Primary data were collected from 406 households. Fundamental orientation theory was used to assess the social impacts of the BTAP, while cost–benefit analysis was applied to examine its economic impact. The results show that the overall social impacts of the BTAP are satisfactory and beneficial, increasing social sustainability by 69% between 2014 and 2018. Additionally, based on the cost–benefit analysis and perception-based analysis, it was found that the BTAP positively affects the economic conditions of rural households. The community livelihood increased during the program, with a total net income of 6.9 million USD in the three districts of KPK. It is concluded that the majority of respondents have benefited from participation in the BTAP. The sustainability of rural livelihood is one of the main concerns related to the establishment of the BTAP. Effort is needed by the government and other parties to both increase rural household income and to protect the environment.

Drivers of Household Decision-Making on Land-Use Transformation: An Example of Woodlot Establishment in Masindi District, Uganda

Land use transformation at the farm level is attributed to household decision-making, reflected by the behavior and activities of smallholder farmers. Unfortunately, household decision-making in local communities and its determinants are site-specific and hardly understood. This study uses multistage purposive selection of households as a unit for the analysis to investigate the transformation from pure agriculture to farm forest mosaics, especially through woodlot establishment. We use key informants, household surveys, and observations to obtain data on decision-making amongst 84 farm households in Nyantonzi parish, Masindi district, Uganda, as an example. Specifically, the study addresses four research questions. Firstly, what is the current status of gender-based decision-making at the household level? Secondly, is decision making within farm households individualistic or collective? Thirdly, which factors are considered to select annual, perennial and tree-crop farm management regimes? Fourthly, what determinants influence the decision-making process and the likelihood of woodlot establishment? A multilevel analysis comprising parametric statistical models and binary logistic regression is applied to assess difference in household natural, physical, human, and social capital, highlight gender roles, and obtain factors associated to selection of crops and determinants of woodlot establishment at the farm level, respectively. Results reveal that gender based decision-making is clearly disaggregated on the basis of husbands and wives and it is individualistic, mostly dominated by husbands with lower participation by wives and other family members. Households consider various factors before making any decisions, e.g., market prices for both annual and perennial crops, food consumption for annual crops, ease of management, and yields from the previous season for the tree-crop management regimes. The likelihood for woodlot establishment is positively influenced by the willingness and intention of households to establish woodlots and relative age of household head. However, knowledge of land use Policies, Laws, and Regulations (PLRs) in relation to tree planting and harvesting and access to non-farm income reduce the likelihood of woodlot establishment. Here, we recommend that current and future forest land restoration initiatives focus on reducing the gender gap and increase women’s participation in decision making, provide market information platforms on wood products, and include woodlot farmers in social organization. Current PLRs on tree tenure should be improved and clearly communicated by using the existing communication assets and social gatherings as channels of change and influence for decision-making.

Impact of Small-to-Medium Size Forest Enterprises on Rural Livelihood: Evidence from Khyber-Pakhtunkhwa, Pakistan

Small-to-medium-sized forest enterprises (SMFEs) offer numerous benefits to rural communities and society as a whole. Less attention has been paid to the sustainability of SMFEs in terms of improving the livelihood of rural communities. This study aims to assess the impact of SMFEs in Khyber-Pakhtunkhwa (KPK), Pakistan, and evaluate their potential role in reducing poverty and promoting rural livelihoods. Primary data were collected from 350 household heads and analyzed using econometric methodologies: The ordinary least squares (OLS) and ordered logit model. Household income, a wealth index, and five capitals of sustainable livelihood have been considered to gauge the impact of SMFEs. The results of the study reveal that there is a strong positive association between SMFEs and improvement in a rural community’s livelihood. The results further showed that households engaged in SMFE-related activities earn 3% more income and possess about 24% more assets. These findings are robust for various dimensions of sustainable livelihood and show positive effects of SMFEs on livelihood assets. This study continues the discussion on several practical implications along with recommendations for future research.

Evidence Types and Trends in Tropical Forest Conservation Literature

To improve the likelihood of conservation success, donors, policy makers, nongovernmental organizations (NGOs), and researchers are increasingly interested in making conservation decisions based on scientific evidence. A major challenge in doing so has been the wide variability in the methodological rigor of existing studies. We present a simple framework to classify different types of conservation evidence, which can be used to understand the strengths, weaknesses, and biases in the conservation effectiveness literature. We then apply this framework to evaluate the evidence for the efficacy of four important strategies in tropical forest conservation. Even though there has been an increase in methodologically rigorous studies over time, countries that are globally important in terms of their biodiversity are still heavily under-represented by any type of conservation effectiveness evidence.

Returns on investment in watershed conservation: Application of a best practices analytical framework to the Rio Camboriú Water Producer program, Santa Catarina, Brazil

Watershed management may have widespread potential to cost-effectively deliver hydrologic services. Mobilizing the needed investments requires credible assessments of how watershed conservation compares to conventional solutions on cost and effectiveness, utilizing an integrated analytical framework that links the bio-, litho-, hydro- and economic spheres and uses counterfactuals. We apply such a framework to a payment for watershed services (PWS) program in Camboriú, Santa Catarina State, Brazil. Using 1 m resolution satellite imagery, we assess recent land use and land cover (LULC) change and apply the Land Change Modeler tool to predict future LULC without the PWS program. We use current and predicted counterfactual LULC, site costs and a Soil and Water Assessment Tool model calibrated to the watershed to both target watershed interventions for sediment reduction and predict program impact on total suspended solids (TSS) concentrations at the municipal water intake-the principal program objective. Using local water treatment and PWS program costs, we estimate the return on investment (ROI; benefit/costs) of the program. Program ROI exceeds 1 for the municipal water utility in year 44, well within common drinking water infrastructure planning horizons. Because some program costs are borne by third parties, over that same period, for overall (social) program ROI to exceed 1 requires delivery of very modest flood and supply risk reduction and biodiversity co-benefits, making co-benefits crucial for social program justification. Transaction costs account for half of total program costs, a result of large investments in efficient targeting and program sustainability. Co-benefits justify increased cost sharing with other beneficiaries, which would increase ROI for the utility, demonstrating the sensitivity of the business case for watershed conservation to its broader social-economic case and the ability to forge institutional arrangements to internalize third-party benefits.

Self-selection into payments for ecosystem services programs

Designers and funders of payments for ecosystem services (PES) programs have long worried that payments flow to landholders who would have conserved forests even without the program, undermining the environmental benefits ("additionality") and cost-effectiveness of PES. If landholders self-select into PES programs based on how much conservation they were going to undertake anyway, then those who were planning to conserve should always enroll. This paper discusses the less-appreciated fact that enrollment is often based on other factors too. The hassle of signing up or financial costs of enrollment (e.g., purchasing seedlings) can affect who participates in a PES program. These enrollment costs reduce overall take-up, and, importantly, they can also influence the composition of landholders who select into the program-and thereby the program's environmental benefits per enrollee. Enrollment costs can increase a program's benefits per enrollee if they are systematically higher for (and thus deter enrollment by) landholders who would have conserved anyway. Alternatively, enrollment costs can dampen per-enrollee benefits if their correlation with status-quo conservation is in the opposite direction. We illustrate these points with evidence from two studies of randomized trials of PES programs aimed at increasing forest cover in Uganda and Malawi. We also discuss how in other sectors, such as social welfare, policy designers have purposefully adjusted the costs of program enrollment to influence the composition of participants and improve cost-effectiveness. We propose that these ideas for targeting could be incorporated into the design of PES programs.

The Danger of Testing by Selecting Controlled Subsets, with Applications to Spoken-Word Recognition

When examining the effects of a continuous variable x on an outcome y, a researcher might choose to dichotomize on x, dividing the population into two sets-low x and high x-and testing whether these two subpopulations differ with respect to y. Dichotomization has long been known to incur a cost in statistical power, but there remain circumstances in which it is appealing: an experimenter might use it to control for confounding covariates through subset selection, by carefully choosing a subpopulation of Low and a corresponding subpopulation of High that are balanced with respect to a list of control variables, and then comparing the subpopulations' y values. This "divide, select, and test" approach is used in many papers throughout the psycholinguistics literature, and elsewhere. Here we show that, despite the apparent innocuousness, these methodological choices can lead to erroneous results, in two ways. First, if the balanced subsets of Low and High are selected in certain ways, it is possible to conclude a relationship between x and y not present in the full population. Specifically, we show that previously published conclusions drawn from this methodology-about the effect of a particular lexical property on spoken-word recognition-do not in fact appear to hold. Second, if the balanced subsets of Low and High are selected randomly, this methodology frequently fails to show a relationship between x and y that is present in the full population. Our work uncovers a new facet of an ongoing research effort: to identify and reveal the implicit freedoms of experimental design that can lead to false conclusions.

Payments for ecosystem services in Mexico reduce forest fragmentation

Forest fragmentation can lead to habitat reduction, edge increase, and exposure to disturbances. A key emerging policy to protect forests is payments for ecosystem services (PES), which offers compensation to landowners for environmental stewardship. Mexico was one of the first countries to implement a broad-scale PES program, enrolling over 2.3 Mha by 2010. However, Mexico's PES did not completely eliminate deforestation in enrolled parcels and could have increased incentives to hide deforestation in ways that increased fragmentation. We studied whether Mexican forests enrolled in the PES program had less forest fragmentation than those not enrolled, and whether the PES effects varied among forest types, among socioeconomic zones, or compared to the protected areas system. We analyzed forest cover maps from 2000 to 2012 to calculate forest fragmentation. We summarized fragmentation for different forest types and in four socioeconomic zones. We then used matching analysis to investigate the possible causal impacts of the PES on forests across Mexico and compared the effects of the PES program with that of protected areas. We found that the area covered by forest in Mexico decreased by 3.4% from 2000 to 2012, but there was 9.3% less forest core area. Change in forest cover was highest in the southern part of Mexico, and high-stature evergreen tropical forest lost the most core areas (-17%), while oak forest lost the least (-2%). Our matching analysis found that the PES program reduced both forest cover loss and forest fragmentation. Low-PES areas increased twice as much of the number of forest patches, forest edge, forest islets, and largest area of forest lost compared to high-PES areas. Compared to the protected areas system in Mexico, high-PES areas performed similarly in preventing fragmentation, but not as well as biosphere reserve core zones. We conclude that the PES was successful in slowing forest fragmentation at the regional and country level. However, the program could be improved by targeting areas where forest changes are more frequent, especially in southern Mexico. Fragmentation analyses should be implemented in other areas to monitor the outcomes of protection programs such as REDD+ and PES.

The effectiveness of Payments for Ecosystem Services at delivering improvements in water quality: lessons for experiments at the landscape scale

Background

Randomised Control Trials (RCTs) are used in impact evaluation in a range of fields. However, despite calls for their greater use in environmental management, their use to evaluate landscape scale interventions remains rare. Payments for Ecosystem Services (PES) incentivise land users to manage land to provide environmental benefits. We present the first RCT evaluation of a PES program aiming to improve water quality. Watershared is a program which incentivises landowners to avoid deforestation and exclude cattle from riparian forests. Using this unusual landscape-scale experiment we explore the efficacy of Watershared at improving water quality, and draw lessons for future RCT evaluations of landscape-scale environmental management interventions.

Methods

One hundred and twenty-nine communities in the Bolivian Andes were randomly allocated to treatment (offered Watershared agreements) or control (not offered agreements) following baseline data collection (including Escherichia coli contamination in most communities) in 2010. We collected end-line data in 2015. Using our end-line data, we explored the extent to which variables associated with the intervention (e.g. cattle exclusion, absence of faeces) predict water quality locally. We then investigated the efficacy of the intervention at improving water quality at the landscape scale using the RCT. This analysis was done in two ways; for the subset of communities for which we have both baseline and end-line data from identical locations we used difference-in-differences (matching on baseline water quality), for all sites we compared control and treatment at end-line controlling for selected predictors of water quality.

Results

The presence of cattle faeces in water adversely affected water quality suggesting excluding cattle has a positive impact on water quality locally. However, both the matched difference-in-differences analysis and the comparison between treatment and control communities at end-line suggested Watershared was not effective at reducing E. coli contamination at the landscape scale. Uptake of Watershared agreements was very low and the most important land from a water quality perspective (land around water intakes) was seldom enrolled.

Discussion

Although excluding cattle may have a positive local impact on water quality, higher uptake and better targeting would be required to achieve a significant impact on the quality of water consumed in the communities. Although RCTs potentially have an important role to play in building the evidence base for approaches such as PES, they are far from straightforward to implement. In this case, the randomised trial was not central to concluding that Watershared had not produced a landscape scale impact. We suggest that this RCT provides valuable lessons for future use of randomised experiments to evaluate landscape-scale environmental management interventions.

Changes of Ecosystem Services and Landscape Patterns in Mountainous Areas: A Case Study in the Mentougou District in Beijing

Land use types have been strongly modified across mountainous areas. This has substantially altered the patterns and processes of ecosystems and the components of ecosystem services (ESs), and could in turn impact the sustainable development. In the mountainous Mentougou district of Beijing, we explored the changes in land use type (cropland, orchard, forested land, scrubland, grassland, bare land, water bodies, wasteland and built-up land), landscape patterns and ESs as well as their interactions during the past 30 years (1985–2014). The ESs included water yield (WY), carbon stocks (CS) and soil retention rate (SR). The results showed that 23.65% of the land use changed and the wasteland decreased by 80.87%. As for ESs, WY decreased by 47.32% since the year 2000, probably due to the increases in temperature and evapotranspiration. Although the decrease of forested land led to the decrease of CS, the increase of vegetation coverage improved SR. CS decreased by 0.99%from 1990 to 2014, and SR increased by 1.38% from 1985 to 2014. Landscape patterns became fragmented and dispersed, and MPS and CS, SHDI and SR were significantly negatively correlated. IJI and CS was positively correlated. This indicated that landscape patterns were highly correlated with ESs. In order to maintain the sustainable development of ESs, we should not only plan land use types, but also consider the rationality of landscape patterns.

Market-Based Conservation for Better Livelihoods? The Promises and Fallacies of REDD+ in Tanzania

Governments, multilateral organisations, and international conservation NGOs increasingly frame nature conservation in terms that emphasise the importance of technically managing and economically valuing nature, and introducing markets for ecosystem services. New mechanisms, such as REDD+, have been incorporated in national-level policy reforms, and have been piloted and implemented in rural project settings across the Global South. By reflecting on my research on REDD+ implementation in two case study villages in Tanzania, the paper argues that the emergence and nature of market-based conservation are multi-faceted, complex, and more profoundly shaped by structural challenges than is commonly acknowledged. The paper identifies three particularly important challenges: the politics surrounding the establishment of community-based forest management; the mismatch between formal governance institutions and actual practices on the ground; and the fickleness of income from carbon sales and alternative livelihood opportunities. I argue that these challenges are not merely teething troubles, but they question fundamental assumptions of market-based conservation, more generally. I end with reference to better ideas for achieving sustainable development.

Payments for environmental services supported social capital while increasing land management

Financial incentives for conservation are popular worldwide, but are also highly controversial. A core concern is that paying for environmental stewardship that community members have historically provided for free will undermine intrinsic conservation motivations or other prosocial attitudes, institutions, and values. We provide rigorous evaluation of the social capital impacts of a large payments for environmental services program. We find that conservation payments in Mexico increased land management activities, did not decrease prosocial work, and improved communal social capital. Although similar studies need to be conducted in multiple contexts, we provide evidence that conservation incentives can support social institutions, attitudes, and values while rewarding environmental stewardship.

Payments for environmental services (PES) programs incentivize landowners to protect or improve natural resources. Many conservationists fear that introducing compensation for actions previously offered voluntarily will reduce social capital (the institutions, relationships, attitudes, and values that govern human interactions), yet little rigorous research has investigated this concern. We examined the land cover management and communal social capital impacts of Mexico’s federal conservation payments program, which is a key example for other countries committed to reducing deforestation, protecting watersheds, and conserving biodiversity. We used a regression discontinuity (RD) methodology to identify causal program effects, comparing outcomes for PES participants and similar rejected applicants close to scoring cutoffs. We found that payments increased land cover management activities, such as patrolling for illegal activity, building fire breaks, controlling pests, or promoting soil conservation, by ∼50%. Importantly, increases in paid activities as a result of PES did not crowd out unpaid contributions to land management or other prosocial work. Community social capital increased by ∼8–9%, and household-level measures of trust were not affected by the program. These findings demonstrate that major environmental conditional cash transfer programs can support both land management and the attitudes and institutions underpinning prosocial behavior. Rigorous empirical research on this question can proceed only country by country because of methodological limitations, but will be an important line of inquiry as PES continues to expand worldwide.

Cultural group selection and the design of REDD+: insights from Pemba

Evolutionary analyses of the ways humans manage natural resources have until recently focused on the costs and benefits of prudent resource use to the individual. In contrast, the fields of environmental resource management and sustainability focus on institutions whereby successful practices can be established and maintained, and the extent to which these fit specific environmental conditions. Furthermore, recent theoretical work explores how resource conservation practices and institutions can emerge through co-evolutionary processes if there are substantial group-level benefits. Here we examine the design of a prominent yet controversial institutional intervention for reducing deforestation and land degradation in the developing world (REDD+), and its ongoing implementation on Pemba Island (Zanzibar, Tanzania) to determine the extent to which the features of REDD+ might allow for the endogenous adoption of sustainable forest management institutions. Additionally, we consider factors that might impede such outcomes, such as leakage, elite capture, and marginal community participation. By focusing on prospective features of REDD+ design that could facilitate the spread of environmentally sustainable behavior within and between communities, we identify distinct dynamics whereby institutional practices might coevolve with resource conservation practices. These insights should contribute to the design of more effective forest management institution in the future.