Abstract
Everyone in the world depends on Earth’s ecosystems and the services they provide, such as food, water, disease management, climate regulation, spiritual fulfillment, and aesthetic enjoyment. Ecosystem Services (ESs) are defined as the direct or indirect contribution of ecological structure and processes to human well-being in the form of (1) provisioning, (2) regulating & maintenance and (3) cultural services (based on the Common International Classification of Ecosystem Services - CICES). This implies that mankind is strongly dependent on well-functioning ecosystems and natural capital that are the basis for a constant flow of ESs from nature to society. Mapping and assessing ESs represent important approaches towards understanding the link between the provision of ESs and human society, which, in turn, facilitates decision-making and management. To effectively manage multiple ESs, it is essential to understand how the dynamics of ESs maintain healthy ecosystems to avoid potential ne ...
Everyone in the world depends on Earth’s ecosystems and the services they provide, such as food, water, disease management, climate regulation, spiritual fulfillment, and aesthetic enjoyment. Ecosystem Services (ESs) are defined as the direct or indirect contribution of ecological structure and processes to human well-being in the form of (1) provisioning, (2) regulating & maintenance and (3) cultural services (based on the Common International Classification of Ecosystem Services - CICES). This implies that mankind is strongly dependent on well-functioning ecosystems and natural capital that are the basis for a constant flow of ESs from nature to society. Mapping and assessing ESs represent important approaches towards understanding the link between the provision of ESs and human society, which, in turn, facilitates decision-making and management. To effectively manage multiple ESs, it is essential to understand how the dynamics of ESs maintain healthy ecosystems to avoid potential negative impacts on human well-being in the context of sustainable development. In this regard, implementing the ES framework in practice requires the identification of the complex interactions among ESs, and between ESs and human demand to optimize future ES provision and to mitigate current trade-offs. However, human demands for natural resources continue to grow rapidly, risking the short supply of ES. By accounting for both the supply and demand ES, it is possible to identify where ESs are not able to satisfy human needs. Mediterranean islands are widely recognized as biodiversity hotspots, with a long history of human activities shaping multi-functional landscapes. Socio-economic and environmental factors are among the most important factors driving the creation of diverse landscapes, with a high supply of ESs. However, these factors, along with climate change, could also have irreversible consequences on local ecosystems, which might have negatively impacted ESs. Within this context, this thesis aimed to improve the understanding of ES occurrence and ES relationships in complex and diverse Mediterranean ecosystems, such as those found in the Ionian Islands. This improved understanding offers important information to decision-makers and landscape planners about the possible impacts that management decisions and actions could cause on sensitive ecosystems. Specifically, the main objectives were to (1) assess the spatial dynamics and interactions among the supply of multiple ES, (2) identify the spatial congruence between the supply and demand of ES, and (3) reveal the socio-ecological factors that determine the spatial distribution of ES bundles in the four prefectures of Ionian Islands; namely, Corfu, Lefkada, Kefalonia, and Zakynthos. First, using a combined set of biophysical indicators and models, ESs were mapped to reveal their spatial distribution. Additionally, ES interactions were investigated by analyzing ES relationships, identifying ES bundles (sets of ESs that repeatedly occur together across space and time), and specifying ES occurrence within these bundles. The three ES groups (provisioning, regulating and cultural) exhibited similar patterns on some islands, but differed on other islands were areas of high recreation presented low provisioning and regulating ESs. Temporal variations showed both stability and changes to the supply and relationships of ESs. Among the islands, different patterns were caused by the degree of mixing between natural vegetation and olive orchards, as the olive bundle delivered the most ESs, while the non-vegetated bundle delivered negligible amounts of ESs. The findings of the spatial and temporal variation in ESs appear to be determined by agriculture, land abandonment, and increasing tourism, as well as the occurrence of fires. Second, using both biophysical and economic indicators, the capacity of ecosystems to provide benefits and societal needs were assessed to reveal ES spatial similarities and mismatches. The results showed that cropland and urban areas presented high demand for all three ES, due to the high presence of the human population, along with tourism activities. In comparison, more than 50% of the Ionian Islands are characterized by natural forests and olive orchards, leading large areas to be dominated by excess ES supply or by similar amounts of both ES supply and demand. The hot spot analysis (Getis-Ord Gi* statistic) conducted to identify spatial mismatches delineated zones with high connectivity, which could facilitate the prioritization of conservation areas. For areas where an unsustainable regime was revealed, recommendations on how to maintain or shift current spatial policies were given to improve the decision-making process. For the most part, results signified that human demands for ES were fulfilled. Consequently, understanding the balance between ES supply and demand can facilitate sustainable spatial planning and enhance the quality of life. Third, to support informed decision-making on landscape management, and implement appropriate planning actions, the final objective of this thesis was to reveal the importance of socio-ecological factors in shaping ES bundles. In specific, 17 socio-ecological variables were explored using an ensemble machine learning method (Random Forest) for their contribution to explaining the supply and demand of ESs. The results showed that the most important variables for the distribution of ES supply bundles were landscape heterogeneity, elevation, slope, landscape connectivity, and population. In comparison, variables representing elevation, slope, and population were among the most important variables contributing to ES demand bundles. The findings demonstrated that research on ESs should account for underlying socio-ecological drivers that influence the supply and demand of ES to improve our understanding of the possible impacts of future management decisions regarding the diverse Mediterranean landscapes of the Ionian Islands. In conclusion, ecosystem services are regarded as an effective communication tool to bridge the knowledge of science, policy-making, and practice, eventually becoming a major tool for decision making on global, national, regional and local scales.
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