| dc.description.abstracteng | Over the last five decades, the growing demand for ecosystem services, such as food, water and fuel has led to the most rapid and extensive changes in ecosystems in human history. Examples for these transformations include the agricultural intensification at the habitat and landscapes scale. In the coming decades this pressure on ecosystems will continue to rise due to an expected further increase in global population and GDP. While these changes in ecosystems have induced substantial net gains in human well-being, they also entail a degradation of regulating and supporting ecosystem services (e.g. water purification, regulation of regional and local climate) that is often greater than what is socially optimal. To address this externality problem, Payments for Environmental Services (PES) are increasingly proposed as an efficient market-based policy instrument.
Previous studies on PES have primarily been based on the Coasean approach. However, practitioners can rarely find or establish the conditions that underlie the Coasean approach, such as perfect information. Critics thus postulate a new conceptualization of PES that accounts for the complexities that characterize the real-world implementation of PES. In this context, the management of uncertainty associated with heterogeneity in the environmental, socio-economic, and socio-cultural background (contextual factors) are of major concern, as well as strategic decisions regarding trade-offs in the PES outcomes, where measures of efficiency are not the sole rationale.
The aim of this thesis hence is to contribute to a better understanding of the relation-ships among contextual background, PES policy design and PES outcomes. More specifically, three research objectives were addressed. First, we assessed the relation between ecological outcomes (bird diversity, bird abundance) and economic outcomes (yields, revenue) of remnant or planted trees in smallholder oil palm plantations, along a management intensity gradient. Second, we investigated the crowding effect, induced by the framing of incentives as PES. Third, the conservation and distributional outcomes of two alternative PES schemes, adopting different implicit fairness criteria, were analyzed.
The empirical analyses were based on survey and ecological data (120 observations), as well as data from framed field experiments (360 observations). The data collection was conducted in the Province of Jambi, Sumatra, Indonesia, between November 2012 and April 2013. In the study region tropical lowland rainforest and extensive traditional production systems have been almost completely transformed into monoculture rubber and oil palm plantations with severe impacts on ecosystem service provision. To mitigate this degradation, wildlife-friendly strategies in which monoculture plantations are enriched with trees planted in gaps within the plantation or with agroforestry buffer zones to surrounding natural vegetation have been proposed.
In the first part of the study we assessed at what cost species diversity (abundance) can be conserved and identified along which section of the management intensity gradient cost-effective options for wildlife-friendly farming systems arise. Focusing on birds, results showed that the restoration of wildlife-friendly oil palm plantations, containing mixed tree stands, can mitigate the loss of diversity (abundance) with respect to edge-tolerant, open habitat and generalist bird species with low conservation status. This gain in diversity (abundance) comes along with a loss in yields and revenue. Since this relationship is non-linear, the marginal shadow price of bird species richness (abundance) changes depending on the initial level of management intensity. In relatively extensively managed oil palm plantations, environmental additionality -in terms of bird species richness- can only be achieved at the cost of relatively high revenue penalties, whereas in relatively intensively managed oil palm plantations the same increase in bird species richness can be achieved at a considerably lower loss in revenue. Results hence suggested that there is room for tree-based enrichment of intensively managed oil palm plantations.
In the second part of this thesis we investigated the extent to which contextual manipu-lations of a policy intervention, such as the explicit framing of an incentive as PES, affect conservation behavior using data from a framed field experiment. The results showed that the PES framing significantly crowds in conservation behavior. Furthermore, results of a zero-one inflated beta regression suggested that this crowding-in effect does not hold for the entire range of participants with different social preferences; the conservation behavior of participants with very weak preferences is not affected by the framing. To further identify mechanisms that can be abstracted from crowding effects, we controlled for social experimenter demand effects. Findings suggested that framing effects are driven by pro-social motives, such as the desire for social conformism or respect rather than by the activation of pro-nature motives. The results of this part highlight the importance for policymakers to take into consideration the contextual manipulations associated with the implementation of a policy and to carefully assess the heterogeneity in the existing preferences for the desired conservation activity.
The last part of this thesis explored the trade-off between conservation and equity considerations in the use of PES. In particular, we investigated the impact of two alternative PES schemes, which are implicitly associated with different fairness principles, on conservation and distributional outcomes under endowment and productivity heterogeneity (differences in opportunity costs of conservation). We tested an equal PES scheme, where a fixed flat rate per conserved hectare is paid, and a discriminatory PES scheme, where redistribution is explicitly considered as a strategic objective. Keeping the conservation fund constant, in the latter scheme the total payment is redistributed by offering higher payments per conserved land unit to low-endowed participants than to high-endowed participants. Results indicated that with the introduction of PES, the conservation behavior at group level significantly increases, indicating that environmental additionality in terms of conservation area can be achieved. Moreover, findings suggested that the introduction of a discriminatory PES scheme can function as a multi-purpose instrument that not only provides environmental additionality similar to an equal PES scheme, but also realigns the income distribution in favor of low-endowed participants and reduces inequality among group members (as measured by the gini index).
In the light of increasingly degraded ecosystems, this thesis illustrated empirically the complexities and context-dependencies associated with the implementation of market-based instruments, such as PES. Further collaborations between ecologists and econo-mists are needed to specify the uncertainties associated with the environmental con-text. Moreover, inducing general principles from observed psychological response pat-terns to the introduction of PES is essential for further research. | de |