# Assessment of Ecosystem Services across the Land-Sea Interface in Baltic Case Studies
## 3 Results
### Ecosystem Services Flow  
An overview of selected ES, chosen indicators and resulting maximal flow values used for the ES flow assessment is shown in Table 2. A detailed description for each indicator and the background for the maximal flow calculation is provided as Supplementary Materials (File S2). In addition, for each indicator the absolute and relative (proportional to the maximal flow) flow values for each CSS are shown. As shown in Table 2, four provisioning ES represented by eight indicators were included in the flow assessment. For the ES 'crops' (P1), 'livestock' (P2), and 'wild food' (P3), different indicators for terrestrial and marine areas had to be chosen, due to the different types of cultured plants and domesticated or hunted animal species. We chose complementary indicators for land and sea. Yet, the flow values for P1 and P2 are not directly comparable due to different units used. Only for 'abiotic energy' (P4) could a common indicator and maximal flow value be applied for terrestrial and marine areas. Results for the CSS show that the ES flow of provisioning ES occurs mostly in terrestrial areas. Only for 'wild food' (P4) is an ES flow shown for terrestrial and marine areas. Here, the absolute flow values are higher for the marine areas of all CSS. Yet, in proportion to the maximal flow values, which differ strongly between land (1 t/km2) and sea (19 t/km2), the relative flow for 'wild food' is higher for terrestrial areas. Hence, our results show that the flow of provisioning ES is dominated by flows from terrestrial areas. 'Local climate regulation' (RM1), 'nutrient regulation' (RM2), and 'pest and disease control' (PM3) were the selected regulating and maintenance ES. The same indicators could be applied for terrestrial and marine areas. However, the approaches for defining maximal flow values and data sources differed between terrestrial and marine areas. 'Local climate regulation' (RM1) is assessed based on the indicator evapotranspiration. Nitrogen cleaning was used as an indicator for 'nutrient regulation' (RM2). For 'pest and disease control' (RM3) two indicators were applied, namely presence of pathogenic bacteria and of micro algae biomass, which were chosen based on their relevance for EU directives, namely the EU Bathing Water Quality Directive (BWD) and the WFD. For RM3, ES flows are assessed based values for coastal waters for marine areas and based on values for lakes for terrestrial areas. A disadvantage of the approach is that it is not applicable in areas without lakes, or only lakes for which BWD and/or WFD monitoring is not required. This was the case for the CSS Greifwald Bay and Curonian Lagoon. Relative flow values for RM1 and RM2 are largely equal for the CSS Schlei and Greifswald Bay. The CSS Curonian Lagoon forms an exception, with a much higher value for nitrogen cleaning for terrestrial areas compared to the other sites, but also in comparison to the relative flow indicated for marine areas of the CSS Curonian Lagoon. Three cultural ES were selected for the flow assessment. For'recreation and tourism' (C1) the ratio between residents and tourists was used as an indicator. 'Landscape aesthetics and inspiration' (C2) was assessed based on two indicators, namely habitat diversity and naturalness. Indicators and maximal flow values for C1 and C2 are equally applied for terrestrial and marine areas. Natural heritage (C3) is assessed based on the proportion of protected areas. It is applied to both terrestrial and marine areas and the same maximal flow value is used, but the flow values for terrestrial and marine areas were assessed separately in each CSS. Flow values for'recreation and tourism' (C3) were similar for all CSS. All CSS got high scores for habitat diversity (C2a), but the strong differences are show for naturalness (C2b). CSS Curonian Lagoon reached a relative flow score of 0.96 (compared to CSS Schlei: 0.48 and Greifswald Bay: 0.71). Thus, the total relative flow for C2 (mean value of C2a and C2b) was found to be highest for the CCS Curonian Lagoon.