1 Introduction
The concept of ecosystem services is seen as a promising approach communicating the links between ecosystems and human well-being (MEA, 2005*). Although the term “ecosystem services” was primary introduced by Ehrlich and Ehrlich (1981), the concept’s origin of the modern history dates back to the late 1960s and 1970s, highlighting the societal value on nature’s functions (King, 1966; Helliwell, 1969; Ehrlich and Ehrlich, 1970; Dee et al., 1973; Ehrlich et al., 1977; Bormann and Likens, 1979). In the 1970s and 1980s, it was already started to point out societal and economic dependence on natural assets in order to attract public interest on biodiversity conservation (e.g. Westman, 1977; de Groot, 1987). Important milestones in the mainstreaming of ecosystem services were on the one hand Daily’s book Nature’s Services: Societal Dependence on Natural Ecosystems (Daily, 1997*) and on the other hand the paper by Costanza et al. (1997*) on the value of global natural capital. The monetary figures presented in the last one resulted in a high impact on both science and policy making. Especially after the release of the Millenium Assessment (MEA, 2003*), which focused on the benefits people derive directly and indirectly from ecosystems, the literature concerning ecosystem services has increased exponentially (Fisher et al., 2009*). Since then, several authors and projects have been dealing with classifying, quantifying, mapping and valuing of ecosystem services in order to integrate the concept into decision making processes (Costanza et al., 1997*; Wilson and Carpenter, 1999; Heal, 2000*; de Groot et al., 2002*; MEA, 2003*; Turner et al., 2003*; MEA, 2005*; de Groot, 2006*; Fisher et al., 2009*; de Groot et al., 2010*; Rounsevell et al., 2010).As landscapes are considered to be multifunctional and are subject to a wide range of land uses, the concept of landscape functions or services, used as synonym to ecosystem services, raised much attention in the field of landscape ecology and landscape planning. The central notion in landscape development has always been that people are part of the landscape and that landscapes are changed for their benefit (Linehan and Gross, 1998; Antrop, 2001). Because landscape sciences focus on spatial pattern and scale, they can provide useful insights into how the spatial distribution of human activities influences important landscape processes and structures from which services are derived (Jones et al., 2008). Especially in Central and Eastern Europe both the analysis of landscape pattern and processes and the assessment of landscape functionality as a precondition for land use planning have a long tradition (Buchwald and Engelhardt, 1968). The idea of landscape function assessment (Bastian and Schreiber, 1994*; Lee et al., 1999) traces back to the multifunctionality concept of forests and green spaces (Konkoly-Gyuró, in press*). Whereas the term “natural territorial potentials” (Troll, 1950; Neef, 1966) was too abstract for practical landscape planning, the concept of landscape functions arose. Bastian and Schreiber (1994) for instance, developed a framework for the assessment of landscape functions to support sustainable land use management. Based on this concept, many studies dealing with different assessment methods, especially in the German speaking community, were carried out (Haber, 1979; Niemann, 1982; Bastian, 1997*; Bastian and Schreiber, 1999*; Leibowitz et al., 2000; Steinhardt and Volk, 2003; Palmer, 2004; Meyer and Grabaum, 2008*).
However, despite the great interest in this research topic there are still remaining challenges which need to be addressed to fully integrate the concept of ecosystem services into landscape planning and decision making (de Groot et al., 2010*). The development of an integrative framework (Figure 1*), which fully take the ecological, the economic as well as the socio-cultural values of landscapes into account, is still in process. Such a framework should be comprehensible, feasible and able to be applied at wide range of scales to different ecosystems or landscapes (Hein et al., 2006*). In the literature many limitations, obstacles and open questions regarding this process are documented and discussed (de Groot et al., 2010*). Because of the wide range of publications on the ecosystem service concept, different approaches to and implementations of the concept occur.
This paper aims at presenting the state-of-the-art of ecosystem service assessment regarding landscape research. The target is to provide a coherent knowledge base contributing to the on-going discussion process on finding solutions for integrating the concept of ecosystem services into landscape planning and decision making. The first sections of this paper address different key definitions used within the concept of ecosystem services and different classification systems of the services. The following sections illustrate various approaches and challenges of quantifying and mapping, different aspects of valuation methods and conclude with a discussion. Although the economic aspect within the concept of ecosystem services also remains as a main challenge, it is only marginally addressed in the present paper, because a review of economic valuation would go beyond the scope of this study. For more detail on this thematic, please refer to other reviews focusing on the economic approach (e.g. Peterson and Sorg, 1987*; Pearce and Moran, 1994*; Gómez-Baggethun et al., 2010*).