The assessment of ecosystems and their services needs spatially explicit data representing the landscape heterogeneity for different areas. Burkhard et al. (2018) underline the need for an integrated framework for mapping and assessment of ecosystems and their services that would support and coordinate the EU member state activities to achieve EU Biodiversity Strategy goals. They present a framework that builds on existing works done by the MAES working group and provides a 9-step approach directed to set up related research and development initiatives and to guide all involved parties through the different steps and related tasks of the process.

A set of indicators for nationwide assessment and monitoring of ecosystem services in Germany has been developed through several ongoing projects (Grunewald et al. 2017). The authors proposed a total number of 51 indicators applicable for 21 CICES classes that have been prioritised for the country by expert-based assessment. Maps of usable wood, avoided soil erosion, flood retention and accessibility of green spaces illustrate the indicators' application. However, “the establishment and legitimating of ES indicators are still at an early stage in Germany” (Grunewald et al. 2017), therefore the authors recommend particular measures developed within the nationwide framework and further integration of the works on different aspects of ES mapping including TEEB NEA-DE and IPBES works.

A conceptual framework for mapping and assessment of ES in Greece is presented by Dimopoulos et al. (2017). It took into account the specifics of the country and the availability of information within the given timeframe. It incorporates ecological data from monitoring and habitat mapping of the Natura 2000 network. The framework is organised into two steps, the first one includes mapping of ecosystem types and assessment of ecosystem condition while the second is focused on the ES mapping. The latter envisages mapping of ES supply, flow and demand as well as ES priority areas mapping, based on a set of indicator matrices. The framework pays special attention to the scale issue which “is considered as crucial for the creation of a reliable index to conduct large (national) scale assessments for various services” (Dimopoulos et al. 2017). The framework is developed within the framework of the Hellenistic Ecosystem Services Partnership (HESP)*4, which also developed an action plan for mapping and assessment of ES in Greece.

An evaluation of ES in Norway, based on a review of the available public reports and research articles, is presented by Skre (2017). It includes estimates and validation of ecosystem services and gives a basis for identifying some conflicts between stakeholders regarding different ecosystem services. A wide variety of ecosystem types is included e.g. mountain ecosystems, forests, agricultural areas, freshwater ecosystems, marine ecosystems and urban areas. The paper deals with how to implement questionnaires and cost-benefit analysis for ES valuation at a national scale.

Biophysical methods for mapping ecosystem services are used to quantify the capacity of ecosystems to deliver services and the amount of this capacity to ensure human benefits. Socio-cultural methods are related to the analysis of human preference, uncovering individual and collective values and perceptions towards ecosystem services in non-monetary units. The sessions dedicated to those methods were focused on the challenges and problems in the spatial aspects of the ES assessment, the challenges in their application for mapping purposes and their potential to derive indicators for ecosystem services supply, flow, demand and trade-offs. The papers included in this Special Issue present mapping of individual or groups of ecosystem services in different case studies around Europe.

Due to the many types of ecosystem services, it is preferable to group them together before attempting further evaluation. A GIS-based ES mapping and valuation model is tested within the real administrative boundaries of a typical municipality in Bulgaria for the purposes of territorial policy integration (Koulov et al. 2017). They also suggest analysing the "Total Economic Value" as the first step in the integrated assessment of ecosystem services in a specific administrative territorial unit. Koulov et al. (2017) succeed in updating the basic terminology supporting ES classification and evaluation by the introduction of the term “ecosystem services dysergy” in the valuation theoretical framework. The investigation overcomes some of the challenges of the application of ES valuation methods at the municipal level and the geospatial analysis of their results. The opportunities, challenges and limitations in the practical application of the ecosystem services concept are outlined.

Yaneva et al. (2018) present an original scientific interpretation of a still controversial issue of the spatial and temporal scales of ecosystem services’ mapping and assessment. They focus on the spatial patterns and the forest ecosystems’ dynamics over time by drawing attention to the soil properties and analysing their influence on ecosystem services supply potential. The study performs a successful experiment on the integration of forest ecosystems monitoring data (ICP Forests) into the biophysical assessment of ecosystem services because it manages to produce reliable maps of two different services (see Table 1). They review generated outcomes with reference to the DPSIR scheme and give feedback on the changes in the terrestrial ecosystems in the last 25-30 years.

Nikolaidou et al. (2017) comment on the particularly important issue of compatibility (synergy) between activities on ecosystem services’ concept implementation in practice with well-established biodiversity conservation approaches and policies such as Habitats (92/43/EC) and Birds Directives (79/409/EC), the Water Framework Directive (2000/60/EC) and the Noise Directive (2002/49/EC). They explore the potential correlation between territories of different or multiple designation types and their capacity to provide ecosystem services. The authors emphasise the need for further clarification of the criteria for assessment of such areas. Nikolaidou et al. (2017) suggest that the designation status of an area can be used as “an alternative tool for environmental policy, indicating the capacity for ES provision”. Multiple designations of areas can be used as proxies for detecting hotspots of ecosystem services. Such type of integration of established evaluation and designation with the ecosystem services’ concept perspectives creates an effective approach for communication with stakeholders and policy-makers in order to motivate them in complying with new standards and demands for nature conservation and environmental management.

The need for mechanisms to capture benefits and costs, as well as its incorporation in decision-making, is discussed by Nijnik and Miller (2017). They argue that ecosystems are complex systems, where neither the ecosystems nor the services that they provide are a sum but are an interrelated system of components. Instead of monetary valuation, they propose participatory approaches, based on mixed methods or the integration of methods. The application was demonstrated by national and local scale studies in Scotland which enable them to evaluate the multiple services provided by forest ecosystems. They conclude that these approaches can provide more complete, comprehensive and impartial insights into a range of benefits that humans derive from ecosystems (Nijnik and Miller 2017).

Two papers (Jacquemin et al. 2017, Stange et al. 2017) deal with assessment and mapping of pollination service. Mapping and assessment approach for informing about zoning decisions regarding urban honeybees by using a modified version the ESTIMAP pollination model is proposed by Stange et al. (2017). The model is applied in Oslo metropolitan area and the study demonstrates testing the policy relevance of ecosystem mapping tools beyond the general purpose of awareness-raising by providing some broader general lessons for ecosystem mapping and assessment. The application of the model enables the authors to produce three kinds of maps, i.e. pollinator habitat quality, relative honeybee foraging and relative resource demand of foraging honeybees. They conclude that, for cities like Oslo, urban development can also produce intermediate levels of habitat fragmentation and result in greater amounts of highly suitable edge habitats that can be found in rural landscapes (Stange et al. 2017). On the other hand, Jacquemin et al. (2017) evaluate the pollination service on a country-wide scale in Belgium by estimating the value of the contribution of insect pollination to the product used for human consumption. They use a methodology for evaluation of pollination at the national level based on crop dependency ratios. The results are presented in the form of maps of total production value and pollination value in monetary terms.

The ecosystem condition for the purpose of MAES is the physical, chemical and biological condition of an ecosystem at a particular point in time (Burkhard et al. 2018). The discussions on this topic during the conference were focused on the identification of appropriate indicators for quantification of the ecosystem condition and the spatial representation of these indicators. Two papers in this Special Issue present different aspects of the ecosystem’s condition. Nedkov et al. (2017) proposed an "integrated index of spatial structure" of urban ecosystems which incorporates built types and land cover from the Local Climate Zones (LCZ) concept with urban ecosystems' classes developed on the basis of MAES typology. The index is used to define vegetation cover and assess the ecosystem condition as part of a general assessment framework for urban ecosystems. The index provides an appropriate basis for characterisation and assessment of the urban ecosystems' condition and ecosystem services and enables the definition of the internal heterogeneity of the urban ecosystems at national level which is one of the main challenges in studying urban ecological systems (Nedkov et al. 2017). Dimitrov et al. (2018) present assessment of the health status of the tree and shrub vegetation in urban green infrastructure in a case study of Karlovo (Bulgaria) by using an integrated application of in-situ observation and remote sensing by Unmanned Aerial Vehicle technology. They prove that the implementation of this flexible approach provides rapid and low-cost results, with good quality of the generated information, which is appropriate as a basis for monitoring of green systems in urbanised areas.

The ecosystems' condition is also mentioned in some of the other papers. The vulnerability of crops to pollinator insect disappearance (Jacquemin et al. 2017) can be used as an indicator for the condition of the agricultural ecosystem which strongly affects pollination service provision. The rate of vulnerability across Belgium is presented in maps which show its spatial variability between different provinces. As Jacquemin et al. (2017) point out, this also makes it possible to discuss the relevance of certain agri-environmental measures by taking into account these dependency relationships between crops and pollinators. Their study shows the necessity to define policy recommendations in favour of the protection of pollinator insects. Koulov et al. (2017) place the assessment of the ecosystem state as an integral part of their framework of the investigation. The schemes, proposed by Burkhard et al. (2018) and Grunewald et al. (2017), define the assessment of ecosystem condition as a key element of the general assessment framework. In addition, Grunewald et al. (2017) point out that a database, that is at least partially provided by the ongoing ecosystem services and condition assessment, is needed for the National Capital Accounting.