A methodological framework to map and assess lake ecosystem services: a multi-temporal analysis study in Lithuania

The importance of freshwater ecosystems is pivotal for human well-being. Lakes, recognized as essential water reservoirs, these ecosystems support the provision of a wide array of ecosystem services (ES) across reams (terrestrial and aquatic). However, anthropogenic activities increase environmental degradation. Consequently, its contribution as ES provider may decrease over time. Thus, it is essential to analyze lake ES assessment over time. Mapping and assessment methodologies for lake ES assessment are scarce. Moreover, indicator data is limited in space and time. Therefore, most ES mapping and assessment research is conducted on a case study basis, focusing on qualitative approaches. Comprehensive quantitative national lake ES mapping and assessments are largely missing but necessary. In this study, we develop quantitative methodological frameworks to map and assess lake ES nationally. The methodologies were applied to Lithuania, which comprises more than 1000 lakes. Since all lakes were unavailable, we utilized information from the HydroLAKES database. The methods use freely available data from national and international databases and remote sensing imagery. In total, 5 ES, defined based on the Common International Classification of Ecosystem Services (CICES), were analyzed: (1) fibers and other material for non-nutritional purposes; (2) water for non-drinking purposes; (3) maintenance of nursery conditions; (4) maintenance of chemical conditions; and (5) recreation. Since lake ES are influenced by their surrounding terrestrial dynamics (e.g., nutrient flows, noise), we included a 5 km buffer around each lake. Land-use dynamics were assessed using Corine Land Cover for 1990, 2000, 2006, 2012, and 2018. The testing of methodology results allowed us to identify general patterns of lake ES supply in Lithuania. The ES fibers and other materials for non-nutritional purposes show a higher supply in the eastern part of Lithuania, which generally increased from 1990 to 2018. The ES water for non-drinking purposes shows only slight changes in its supply over time. The maintenance of nursery and chemical conditions ES show a decline in the supply over time, especially in the northeastern part of the country. The ES recreation also shows nearly no changes in its supply over time.

This study was conducted under the framework of the “Lithuanian lake ecosystem services: impacts of climate and land-use change” (LACLAN) Project. This project receives funding from the European Social Fund under the No 09.3.3-LMT-K-712 “Development of Competences of Scientists, other Researchers, and Students through Practical Research Activities” measure.