Payments For Ecosystem Services Schemes Research Articles

Ecosystem services provided by South African palmiet wetlands: A case for investment in strategic water source areas

Wetlands globally are highly threatened by agriculture, and damage associated with it, such as invasion by alien species and the impacts of fertilizers and pesticides. South African palmiet wetlands make an interesting case study to investigate this, as they are valuable valley-bottom, peat-forming systems, highly threatened by agricultural development. Currently most agriculture in these palmiet wetlands is marginal (low agricultural productivity) due to the challenges of farming a system that experiences severe floods and erodes rapidly, forming gullies, when wetland vegetation is disturbed. The current situation seems to be a lose-lose situation for nature and society. We aimed to assess this conflict between water-related services and agriculture objectively by comparing provision of fifteen ecosystem services by degraded and pristine sections of three palmiet wetlands using a rapid ecosystem service assessment tool (WET-Ecoservices). To validate this technique, we compared results to those obtained from examining three key ecosystem service complexes in slightly more detail. We found that pristine palmiet wetlands provide valuable ecosystem services to society, which are currently being compromised for private, marginal agricultural gain. These pristine wetlands sequester between 21 and 41 g.m−2 of carbon per year, have nitrogen and phosphorus uptake efficiencies of 62–85% and 16–89% respectively, and provide about 16 times more flood attenuation relative to degraded ones. The full impact of degradation on wetland ecosystem services was not entirely captured by the rapid ecosystem service assessment tool: WET-Ecoservices. We suggest some adaptations to this tool for the valley-bottom wetland hydro-geomorphic unit. Overall, these wetlands have high potential for incorporation into a Payments for Ecosystem Services scheme, due to the ecosystem services provided and their position above important municipal dams. We recommend collaboration between private landowners struggling with marginal agriculture, and decision makers in cities dealing with water shortages and debt to ensure the most efficient and judicious use of these palmiet wetland ecosystem services.

Motivational Crowding in Payments for Ecosystem Service Schemes: a Global Systematic Review

We contribute to the growing body of literature on the ecological and socio-psychological impacts of providing payments as rewards for conservation. We conducted a systematic review of 74 payments for ecosystem services (PES) schemes and identified contextual factors that correlate with psychological mechanisms that enhance (”crowd-in”) or erode (”crowd-out”) autonomous motivation. Such indicators of crowding-in were more likely when schemes empowered local participants, provided in-kind non-monetary community benefits, and aimed to foster feelings of autonomy. Schemes that thwarted feelings of autonomy correlated with indicators of motivational crowding-out. Although motivational crowding had no effect on ecological success, indicators of crowding-in positively predicted social success (χ2 = 8.60, n = 48, p = 0.003) and crowding-out negatively predicted social success (χ2 = 9.59, n = 47, p = 0.002). Compared to past studies highlighting the negative impacts of extrinsic rewards on autonomous motivation, our study provides a more nuanced perspective and demonstrates that extrinsic incentives such as payments can promote crowding-in of autonomous motivation if schemes are designed equitably and provide opportunities for autonomous decision-making. Our study demonstrates how the application of psychological theories can contribute to the design of fair and effective PES schemes.

Achieving forest conservation in Fiji through payment for ecosystem services schemes

Most forests in Fiji are on native land owned by communities with tenure rights that are held largely with clans. Although there are examples in Fiji of local communities setting up conservation areas to protect their valuable forest resources, many are under pressure to issue leases to logging or mining companies for much-needed income. With inadequate legislation and government resources to secure the long-term protection of natural forests, conservation practitioners are looking at alternative models for establishing forest conservation areas in Fiji. One such model is the application of a forest payment for ecosystem services (PES) scheme to deliver both ecological and socioeconomic outcomes for local communities. A case study from Kilaka village, Fiji, is presented where the Wildlife Conservation Society (WCS) has worked with traditional land owners to secure a 99-year conservation lease for 402ha of pristine native forest in Vanua Levu. The lease, which was brokered through the government iTaukei Land Trust Board, provides an alternative source of income to logging and mining. The management plan which is nested within a larger ecosystem-based management plan for the district, sets out the comanagement arrangements between the community and WCS, with the day-to-day management of the forest, enforcement, monitoring and evaluation led by the traditional landowning clan. This PES model and co-management arrangement has potential for replication to other priority forest areas to meet Fiji’s obligations under the Convention on Biological Diversity, but at an estimated financial cost ranging from US$69.0–287.8 million.

Different ecosystem services, same (dis)satisfaction with compensation: A critical comparison between farmers’ perception in Scotland and Brazil

Payments for Ecosystem Services (PES) schemes have increasingly expanded to consider ecosystem services (ESS). In Brazil, the Forest Code permits PES but does not specify the scheme operationalization. The way ESS should be quantified and valued has not yet been implemented country-wide, nor has the funding source for PES. Through interviews with farmers in Rio Claro-SP, Brazil, and in Cairngorms National Park in the highlands and lowlands of Scotland, UK, we compared farmers’ perspectives concerning ESS and PES, focusing on the PES implementation in sugarcane landscape in São Paulo state. While Scottish farmers perceived more cultural services, Brazilian farmers focused on regulating services, which we attribute to socio-political and landscape differences. Despite these differences, farmers in both areas preferred opportunity cost approach for ESS valuation because this method captures efforts to maintain ESS. Thereby, the opportunity cost should be considered for valuation in PES schemes, but conversely, budgetary constraints make it impossible to satisfy farmers with PES in regions of high productivity in the southeast of Brazil. Lessons learned concerning the PES subsidies in Scotland indicates the importance of co-designing schemes with stakeholders, minimizing trade-offs between the environment. Therefore, the participants as ESS providers, beneficiaries and intermediaries in the public policies arena was recognized for co-optimize the trade-offs between costs and effectiveness in PES.

A machine learning approach to map tropical selective logging

Hundreds of millions of hectares of tropical forest have been selectively logged, either legally or illegally. Methods for detecting and monitoring tropical selective logging using satellite data are at an early stage, with current methods only able to detect more intensive timber harvest (>20 m3 ha−1). The spatial resolution of widely available datasets, like Landsat, have previously been considered too coarse to measure the subtle changes in forests associated with less intensive selective logging, yet most present-day logging is at low intensity. We utilized a detailed selective logging dataset from over 11,000 ha of forest in Rondônia, southern Brazilian Amazon, to develop a Random Forest machine-learning algorithm for detecting low-intensity selective logging (<15 m3 ha−1). We show that Landsat imagery acquired before the cessation of logging activities (i.e. the final cloud-free image of the dry season during logging) was better at detecting selective logging than imagery acquired at the start of the following dry season (i.e. the first cloud-free image of the next dry season). Within our study area the detection rate of logged pixels was approximately 90% (with roughly 20% commission and 8% omission error rates) and approximately 40% of the area inside low-intensity selective logging tracts were labelled as logged. Application of the algorithm to 6152 ha of selectively logged forest at a second site in Pará, northeast Brazilian Amazon, resulted in the detection of 2316 ha (38%) of selective logging (with 20% commission and 7% omission error rates). This suggests that our method can detect low-intensity selective logging across large areas of the Amazon. It is thus an important step forward in developing systems for detecting selective logging pan-tropically with freely available data sets, and has key implications for monitoring logging and implementing carbon-based payments for ecosystem service schemes.

Positive effects of payments for ecosystem services on biodiversity and socio-economic development: Examples from Natura 2000 sites in Italy

Payments for ecosystem services (PES) are promising instruments to create additional funding for biodiversity conservation, but related socio-economic effects are rarely assessed. This study aimed at evaluating socio-economic benefits using a set of indicators related to 13 topics. Based on 50 cases in 21 Natura 2000 sites in Italy, our results revealed positive effects on the socio-economic development of the local communities as well as an improvement in the defined conservation objectives. At greater spatial scales, potential effects were related to an increase in knowledge, innovation, and public finances supporting a green economy. Our results suggest that the level of socio-economic impacts is determined by a combination of several factors, including the type of ecosystem services, the conditions of the PES agreement, and the general socio-economic context. Specifically, PES related to regulating (e.g., water recharge, flood mitigation) and cultural services (e.g., recreational value) had positive effects on ecological and socio-economic conditions. Our findings highlight how PES schemes in protected areas can contribute to overcoming biodiversity finance gaps and strengthen sustainable development. However, PES should be planned carefully to not privilege individual ecosystems or services. As PES focus on a rather short period, long-term effects need to be evaluated.

Public discourses on conservation and development in a rural community in Colombia: an application of Q-methodology

People living in rural areas are caught between the two often conflicting objectives of conserving biodiversity and promoting economic development. Current approaches to conservation are built on the premise that conservation and development are not antagonistic. Social conservationists advocate win–win solutions that both conserve biodiversity and promote human well-being. In this paper we explore how the conservation-development relationship is understood by a rural community in Colombia where remaining areas of tropical dry forest are threatened by human activities, and a payment for ecosystem services scheme, PES, is proposed as a conservation strategy. Q-methodology was used to identify and categorise local peoples’ perspectives on forest conservation. Four distinctive perspectives were found: Social Conservationism, Fair Development, Development Advocate and Government’s Responsibility. Social conservationism places more importance on forest conservation while the other three perspectives emphasise development. This suggests that the conservation program at the local level must be explicit about tensions and trade-offs. Not to do so can compromise the social acceptability of the PES scheme and therefore the conservation objective.

Business attitudes towards funding ecosystem services provided by urban forests

Urban trees and woodlands provide a wide range of ecosystem services (ES) to society, for example, flood risk reduction, air purification, and moderation of urban heat islands. Despite this, local government budgets for tree planting and maintenance have declined in many cities throughout the world. Thus far, the academic literature has largely ignored whether businesses are willing to help fund urban forests and the ES they provide. Business financing via payments for ecosystem services (PES) within the urban realm is also under-researched and lacking in practice. This study aims to address these research gaps. Semi-structured interviews were carried out with 30 businesses of varying sizes and sectors, operating in Southampton, UK. Respondents thought a public-private partnership would be feasible, with a focus on voluntary payments towards enhancing air quality, reducing flood risk, and improving aesthetics. Respondents would prefer to choose from a list of location-specific, cost-effective, monitored projects to fund directly, for marketing and/or corporate social responsibility purposes. To facilitate business funding of urban forest-based ES, clear communication of the expected environmental benefits and a strong business case are required, drawing on the experience of similar initiatives. From our findings, we recommend the piloting and analysis of such PES schemes.

Can Payment for Ecosystem Services Schemes Be an Alternative Solution to Achieve Sustainable Environmental Development? A Critical Comparison of Implementation between Europe and China

The term “Ecosystem Services” was coined to indicate “all the multiple benefits humans obtain from ‘natural capital’ (i.e., the world’s stock of natural assets—geology, soil, air, water—including living things and beings)” that make human life possible, such as natural water purification, flood control by wetlands, and others. The concept expanded to include, nowadays, socio-economic and conservation objectives, and has been further popularized by the Millennium Ecosystem Assessment (MEA) in the early 2000s, as well as by the “Paris Agreement” reached at the 2015 UN Conference on Climate change (COP21). Payments for Ecosystems (or Environmental) Services (PESs) are financial incentives given directly to landholders to compensate them for implementing good land management, including conservation activities. Such compensation encourages them to “voluntarily” provide (or continue providing) such services, instead of monetizing their “natural capital” otherwise. This approach has been figuratively described as “making trees worth more standing than cut down” Examples of important PES schemes, implemented in China and in Europe, are described and analyzed in this paper, focusing on the methods applied, to assess their evolution over time, and attempt to identify which solutions could be most effective.

Incentivising Participation and Spatial Coordination in Payment for Ecosystem Service Schemes: Forest Disease Control Programs in Finland

This paper considers the problem of designing PES-type contracts to encourage participation and spatial coordination amongst private forest owners in Finland. The aim of the policy is to increase efforts to mitigate risks from invasive forest pests and diseases. Such control actions yield spill-over benefits to other landowners and to wider society, meaning that the level of privately-optimal disease control is likely to be less than the socially-optimal level. The policy designer may wish to encourage spatial coordination in the uptake of such PES-type contracts, as spatial coordination delivers an increase in the effectiveness of control measures on disease risks. We conducted a choice experiment with private forest owners in Finland in October 2016. The study elicited the preferences of woodland owners with respect to the design of forest disease control contracts, and gauged their willingness to cooperate with neighbouring forest owners within the framework of such programs.

Payments for forest ecosystem services: a look at neglected existence values, the free-rider problem and beneficiaries' willingness to pay

Payment for ecosystem services (PES) programs have emerged as a financial mechanism to ameliorate market failures associated with the multitude of non-market ecosystem services (ES) provided by forest ecosystems. However, the defining principles of PES in theory is far from what pertains in practice. Focusing on the concept of total economic value (TEV) of ES, we identify that PES often include compensation as a proxy for the supply of ES and largely neglect to encompass the different attributes of an ES' TEV, particularly existence values. Most PES schemes are limited by scope of funding and incentives often account for as little as 0.1% to 8.5% of the full annual ES economic values per ha. The mechanism of PES therefore needs to be broadened to integrate potential levels of payments that direct and indirect beneficiaries might be willing to pay to preserve forest ecosystems and their services. Some beneficiaries might be willing to pay for some ES and altruistically expect others to free-ride on their payment. Research efforts should aim at providing better understanding of beneficiaries' willingness to pay in order to expand the demand-side of PES and reduce uncertainties.

Multi-purpose forest management in the tropics: Incorporating values of carbon, biodiversity and timber in managing Tectona grandis (teak) plantations in Costa Rica

Plantation forestry is the ultimate alternative in reforesting degraded tropical ecosystems and in provisioning multiple ecosystem services beyond timber production. Therefore, we studied the management of Tectona grandis L.f. (teak) plantations in Costa Rica and simulated alternative management strategies incorporating simultaneously the values of carbon storage, biodiversity and timber production. Alternative management strategies included (1) extension of rotations, (2) reduced thinning and (3) conversion of even-aged to uneven-aged systems. Evaluation criteria were carbon storage in biomass, stand structural diversity as a proxy of biodiversity, and economic return from timber harvests. For growth predictions under future climatic conditions, we calibrated the hybrid forest growth model 3PG. We found that carbon storage could be increased by increasing rotation periods (e.g. +29.7% of carbon for a 50% increase in rotation length) and a no thinning management (+9.5% of carbon). For rotation extension associated economic losses were high (e.g. at 5% discount rate, the Land Expectation Value (LEV) decreased by 25.1% for a 50% extension of rotations). For thinning LEV increased with a low-thinning regime, but decreased with a no-thinning management (+9.5% and −23.6%, respectively). Payments for ecosystem services (PES) increased economic return by about 3–4%. Structural diversity increased by conversion to uneven-aged forest stands (Gini coefficients for basal area increased from 0.21 to 0.52). Economic returns from timber harvests were almost equal for even-aged and uneven-aged systems at 1% discount rate (max. −2% of LEV). At 5% discount rate, we observed economic losses of 11.1–20.1% compared to the even-aged scenario. At 10% discount rate, economic losses ranged between 43.6 and 104%. We concluded that extension of rotations and reduction of thinning intensity can be used as management strategies to increase the carbon storage of teak plantations. However, to compensate the associated economic losses through a PES scheme, payments for carbon sequestration need to be increased and special incentives for longer rotation periods and low thinning management need to be developed. The transformation into uneven-aged forest stands requires active investment at discount rates higher than 1%. Whether this investment can be offset by benefits from biodiversity and increased forest resilience is unknown and requires further investigations. Other measures of biodiversity conservation, such as the use of native and mixed tree species and the retention of old trees and deadwood are moreover necessary.

The economic value of high nature value farming and the importance of the Common Agricultural Policy in sustaining income: The case study of the Natura 2000 Zarandul de Est (Romania)

This study assesses the economic value of land use changes in the Zarandul de Est (Romania) Natura 2000 site, applying the ecosystem services approach proposed by the TESSA toolkit. The aim is to provide support to decision-making in the context of high nature value farming, debating the contribution of public subsidies and agri-environmental schemes to farmers' income. Local and global agroforestry ecosystem services are compared under two different land use scenarios: 1) land abandonment followed by natural afforestation; 2) sustainable cattle grazing in semi-natural grasslands. The scenario analysis shows that an improved use of pasture land determines a relevant increase in net economic value. However, direct and rural agro-environmental payments applied to high value nature farming are necessary to provide viable financial support to farmers and achieve the economic impacts described by the ecosystem services approach. Under the 2007–2013 rules, Common Agricultural Policy payments show to be equal to 130% of the household income and able to cover the full cost of the average farm in Zarand, a figure similar to other European marginalised areas. This result suggests that public support, in the absence of a full implementation of payment for ecosystem services schemes, is necessary to limit socio-economic deprivation of European marginalised farming systems. However, without reaching smallholders (farmers holding <1ha) and commoners (farmers using common grassland) who are both currently excluded, the current state agricultural payments shows limited impacts in sustaining the resiliency of the Zarand socio-ecological system. As alternatives to CAP payments, income diversification strategies (e.g. ecotourism, incentives to re-wilding) are proposed as well as the required conditions under which they can be applied, and in what terms these strategies can sustain the strict requirements of halting biodiversity loss in Natura 2000 sites.

More than just linking the nodes: civil society actors as intermediaries in the design and implementation of payments for ecosystem services–the case of a blue carbon project in Costa Rica

ABSTRACTWhile in many cases the benefits of ecosystem services (ES) can be enjoyed on different scales, the provision of ES requires engagement and commitment at the local scale. Therefore, the local level becomes important when thinking about compensation schemes or payments for ecosystem services (PES) as an approach to managing ES. The difficult task of bringing together different actors and institutions at different scales for specific conservation projects at the local level often remains in the hands of intermediaries. In this paper, we investigate the role of a civil society organisation (CSO) as an intermediary organisation in a PES scheme, the Community Blue Carbon Project (CBCP) in Costa Rica. To assess the role of intermediaries in a PES scheme, we rely on social network analysis and examine the position and role of the intermediary organisation. Based on Net-Map interviews, which is an interview-based mapping tool that helps people understand, visualise, discuss and improve situations in which many different actors influence outcomes, we find that the intermediary organisation in the CBCP is composed of several institutional and individual intermediaries who create both formal networks for connecting the international to the local level and informal networks for creating trusting relationships among the actors. Different spatial levels are reflected within the CSO’s organisational structure, and the CSO mitigates the distributional, procedural, recognition and contextual aspects of environmental justice.

Can Payments for Ecosystem Services Improve the Management of Natura 2000 Sites? A Contribution to Explore Their Role in Italy

Financing protected areas is crucial for guaranteeing the flow of ecosystem services (ES) provided by natural and semi-natural ecosystems, which are the basis of human well-being. In the last two decades, together with traditional conservation tools, innovative instruments, such as PES (Payment for Ecosystem Services), have been proposed and implemented all over the world in order to improve management effectiveness in biodiversity conservation. In this paper we identified and categorized 33 PES case studies in 19 Natura 2000 sites developing the hypothesis that a PES approach may contribute to improving the effectiveness of conservation actions at different spatial and administrative levels. We found that in these areas, farmers and foresters often allow the maintenance of natural and semi-natural ecosystems through their economic activity. Through PES schemes their important role can be formally acknowledged, both in environmental and economic terms. PES schemes are also a tool for involving more stakeholders, particularly local companies, residents and tourists in conservation actions. So PES can actually improve Natura 2000 sites’ management and increase the availability of financial resources in favor of conservation actions. However, careful attention must to be paid to the supporting role of public authorities, generally crucial for the success of a PES.

Exploring Institutional Factors Influencing Equity in Two Payments for Ecosystem Service Schemes

Payments for Ecosystem Services (PES) are considered promising instruments for promoting conservation and addressing socio-economic goals, including equity. While several studies analyse how institutions enable the delivery of cost effective conservation, fewer studies focus on the role that informal institutions play in influencing equitable outcomes especially in Africa. Focussing on the role of formal and informal institutions, this article contributes to the emergence of work that reflects alternative conceptualisations to mainstream neoclassical understandings of PES. A qualitative research approach is applied analysing two Kenyan cases to illustrate how historical institutional processes influence present day equity outcomes. The study explores both procedural and distributive equity. The results reveal that despite very similar land tenure origins, the schemes differ considerably regarding their equity outcomes. Formal and informal institutional interplay was found to influence perceptions of land value over time and bargaining processes are identified as determinants of the different equity outcomes. The study also reveals that institutional interplay may influence the simultaneous achievement of different equity dimensions. The study therefore recommends the integration of mechanisms that reconcile both formal and informal institutions, such as land tenure distribution and cultural norms in design and implementation of PES schemes to better achieve equity.

Power Strategies for Ecotourism in the Fernando de Noronha Archipelago (Brazil) for Implementing Payments for Ecosystem Services

Ecotourism is considered an important activity provided by natural ecosystem services in the Fernando de Noronha archipelago through recreation opportunities. Since 2010, the Fernando de Noronha National Marine Park has been experiencing a private-public partnership between the park’s management and a concessionaire, imposing fees to visitors in order to provide sustainable facilities to some attractions of the protected area. Payments for ecosystem services schemes are being implemented in many parts of the world in an effort to promote environmental protection, showing positive outcomes. Therefore, the objective of this study is to analyse the empirical case of payments for ecosystem services through ecotourism based on economic and political theory. The economic theory identifies the economic processes generated by the payments, while the political theory identifies the political actors and their respective power strategies that aid in the implementation of a specific scheme of payments for ecosystem services. Furthermore, the aim of the study is to determine which factors are successful in utilizing payments for ecosystem services as an instrument to preserve ecosystems via ecotourism. Moreover, the paper links an economic approach to power theories, which is a dynamic perspective on tourism studies. To reach the results, economic and political factors are identified according to existing theory and are then compared with empirical evidence from the archipelago. The most powerful actors that have influence on the ecotourism activities were interviewed in order to determine their power elements as well as their level of support for the payments, according to the power analysis that take into consideration the following power elements: coercion, incentives, and disincentives and dominant information. The economic analysis shows that payments for ecosystem services sufficiently meet the standards of the economic model and the political analysis explains this success by the influence of various powerful actors in Fernando de Noronha. Furthermore, the results support the hypothesis that only payments for ecosystem services which can gain the support of powerful actors are effective in practice. Subscribe to JPRA

Payments for Ecosystem Services Incentives and Adoption of Land Use Interventions in Uluguru Mountains, Tanzania

The role played by Payments for ecosystem services (PES) in promoting land use interventions is increasingly being recognized as an important instrument for changing land use management worldwide. Despite the increase, adoption of land use interventions promoted by PES and factors influencing it are not well understood. This study was carried out to assess the adoption of land use interventions promoted by PES scheme four years after its implementation in the Uluguru Mountains, Tanzania. The specific objectives of this study were to assess the adoption and factors that influenced it. The study employed questionnaire survey method to collect data from 219 households selected randomly. Focus group discussions and key informant interviews were also conducted to complement information obtained through questionnaire surveys. Descriptive and inferential statistical analyses were employed. Binary logistic regression was used to analyse quantitative data obtained, while content analysis was applied to qualitative data. Results revealed that during the project implementation, 40% of the households did not adopt any of the promoted interventions. Unexpectedly, four years after the project ended, every household sampled had adopted the interventions. Households headed by younger heads and those with land ownership, households which received PES incentives and lived for a long time in the same area and those with more labour force and access to extension services were found to have adopted more interventions (p ≤ 0.05). Thus, the study concludes that socioeconomic characteristics, agricultural extension services and incentives initially provided to farmers are key factors influencing the adoption of land use interventions. Therefore, it is recommended to the government that it should support farmers to get land tenure and to provide them with more incentives to improve their farms through adopting technologies.

Improving Spatial Coordination Rates under the Agglomeration Bonus Scheme: A Laboratory Experiment with a Pecuniary and a Non‐Pecuniary Mechanism (NUDGE)

The Agglomeration Bonus is a Payment for Ecosystem Services scheme that focuses on achieving spatially‐coordinated land use across neighboring, privately‐owned agricultural properties. In this article, I use a laboratory experiment to examine the role of two mechanisms in incentivizing spatially‐coordinated land uses under the Agglomeration Bonus scheme on a geographical landscape resembling a local circular network. The first mechanism is pecuniary in format and varies the payoffs associated with coordination, while the second is a non‐pecuniary mechanism that varies the amount of information participants have about the land use choices of other participants, specifically of those from another community. The payoff variation is implemented as a within‐subject treatment and the information treatment in a between‐subject format. The results indicate that the coordination rates are higher if payments associated with coordination are higher. Also, having information about outcomes of the Agglomeration Bonus scheme from another community improves spatial coordination rates in both communities.

Uncertainties in demonstrating environmental benefits of payments for ecosystem services

Payments for Ecosystem Services (PES) have become the flagship of conservation organizations in recent years. However, PES schemes are as much criticized as they are acclaimed in the literature. Researchers have pointed that many PES schemes, particularly water-related ones, are based on unreliable assumptions and lack strong causal links between land use and ecosystem services. Evidence of outcomes is hardly demonstrated. This uncertainty in PES schemes arises not only from practical difficulties, but from the complexity of the human-environment systems (HES), and the limits of current knowledge about HES. Many scientists and practitioners have proposed that more research is needed to improve the scientific basis of PES. Here we argue that this research should be complemented with a deeper understanding of the uncertainties involved in PES, an explicit treatment of these in the whole process of PES negotiation, design and monitoring, and clear uncertainty communication among the actors involved. Neglecting uncertainties could lead to unfounded expectations and poor assessments of PES outcomes. If recognizing and accounting for uncertainties are to threaten the success of PES, then uncertainty can be seen as an opportunity to open up the dialogue to alternative ways of achieving the desired conservation goals.