Multifunctionality of landscapes - an ecosystem service perspective

With increasing population growth, changed consumption patterns and the resulting need for resources, the management and use of cultural landscapes has intensified during the last century. Due to this intensification, cultural landscapes in Europe and other human-dominated regions around the world have transformed from multifunctional landscapes (i.e. providing a diverse set of ecosystem services) to more specialized and uniform landscapes (i.e. providing fewer ecosystem services). Since the widespread loss of ecosystem services can seriously affect human well-being, scientists and intergovernmental organizations have increasingly called for the restoration of multifunctionality at the landscape scale. This again resulted in a growing body of literature on the topic and an uncertainty about what multifunctionality actually is about and how to assess multifunctionality. In this dissertation, the focus is on ecosystem service-based multifunctionality (i.e. the quantification of multifunctionality through ecosystem services). Studies of this field generally examine how different ecosystem services interact, where their overall supply is highest and which factors influence the capacity of a landscape to provide multiple ecosystem services. The consideration of multiple ecosystem services at the landscapes scale specifically enables landscapes and the complex interactions within landscapes to be viewed and studied as socio-ecological systems. The assessment of ecosystem service-based multifunctionality is therefore regarded as an important tool for finding sustainable solutions in landscape management. The overall aim of this dissertation was to enhance and strengthen the concept of multifunctionality from a scientific point of view, and to provide novel conceptual and empirical insights on landscape multifunctionality that are relevant for environmental planning and management. In this dissertation, I have specifically focused on three topics that present challenges for the assessments of ecosystem service-based multifunctionality: 1) overcoming the conceptual and methodological uncertainties related to quantitative multifunctionality assessments, 2) accounting for spatial variability of ecosystem service supplies and 3) differentiating between stakeholders’ perspectives on multifunctionality. Each article of this cumulative dissertation focuses on one of the three challenges: The first article (Chapter 2) presents a quantitative literature review of 101 multifunctionality assessments. Conceptual and methodological differences between ecosystem function- and ecosystem service-based multifunctionality assessments were identified, as well as the most commonly used multifunctionality metrics: threshold approaches, average or sum approaches and diversity indices. The second article (Chapter 3) uses 18 ecosystem service indicators to quantify multifunctionality at the municipality scale (alpha-multifunctionality) and further introduces a new multifunctionality indicator (beta-multifunctionality) that accounts for the unique ecosystem service contributions of municipalities to regional multifunctionality. The results of this article show how multifunctionality at the municipality scale, as well as the unique contributions of municipalities to regional multifunctionality vary across Europe and across different land system archetypes. Finally, the third article (Chapter 4) of this dissertation uses eleven ecosystem service indicators to quantify multifunctionality in two peri-urban landscapes in Europe: the Vereinigte Mulde in Germany and the Kromme Rijn in the Netherlands. By weighting the ecosystem service indicators with stakeholder-derived valuations of the ecosystem services, a differentiation between multifunctionality beneficiaries was achieved. The main contributions of this thesis therefore include an overview of the most recent multifunctionality assessments and the testing of two alternative approaches to assess ecosystem service multifunctionality. By compiling previously used methods and linking them with the most recent conceptual advancements in scope of the literature review, I showed that a clear distinction between studies with an exclusively ecological focus and studies with a more integrated socio-ecological perspective is needed to strengthen the application of the multifunctionality concept. As a follow up on this review, I was able to derive common steps in multifunctionality assessments, as well as recommendations for future studies. In scope of the second and third article, I was able to highlight some specific challenges in current multifunctionality assessments and to test methods that go beyond the common quantification of multifunctionality at single spatial scales or for society as a whole. First of all, my work shows that, due to spatial variability of ecosystem service supplies, the diversity of ecosystem services (alpha-multifunctionality) cannot be maximized in all areas. Accounting for unique ecosystem service supplies (beta-multifunctionality) could thus be more relevant for finding viable land management solutions than assessing ecosystem service hotspots only. This approach is especially applicable, if maximizing (alpha-) multifunctionality is not possible or wanted. Second, maintaining a high diversity of ecosystem services is only meaningful, if the ecosystem services are demanded by society and if no land use conflicts evolve through increased multifunctionality. In my last research paper, I therefore show that accounting for different perspectives of stakeholders on landscape multifunctionality is another crucial aspect for finding viable and sustainable land management solutions. All in all, I conclude that maintaining a high diversity of ecosystem services that relevant to various stakeholders and at spatial scales that allow an implementation of multifunctionality, is important for preventing environmental degradation and for ensuring that society as a whole can benefit from landscape multifunctionality. Quantitative multifunctionality assessments can be used in various ways to answer current research questions in landscape ecology and thus to support the maintenance of ecosystem services in cultural landscapes. However, further development, improvement and applications are needed for multifunctionality assessments to work as strong tools for management and decision-making