1.1. International classifications of ecosystem services

The overview of the source literature about economic, social and ecological assessment of ecosystem services can be found in [1]. The basic information about the assessment of ecosystem services is provided by [2]. In general, it can be stated that a huge amount of studies focused on the assessment of ecosystem services were published in the last decades. The Economics of Ecosystems and Biodiversity (TEEB) is a joint initiative of the European Commission and the United Nations Environment Programme [3] and is of considerable importance in Europe. It was arranged by the European Commissioner for Environment with the aim to draw attention to the global economic contribution of biodiversity and to the expenses connected to biodiversity loss and ecosystem degradation [4].

Nowadays, there are three international classifications of ecosystem services: the Millennium Ecosystem Assessment (MEA), the Economics of Ecosystem and Biodiversity (TEEB) and Common International Classification of Ecosystem Services (CICES). Depending on a specific context, each classification has its positive and negative sides [5].

Millennium Ecosystem Assessment [6] is based on the interconnection of people and ecosystems. Therefore, the changes of living conditions of society have a direct or indirect impact on ecosystem changes and vice versa. According to the MEA, there are several kinds of services: supporting, providing, regulating and cultural (which include also recreational services).

In the second half of the twentieth century, ecological economics started to be formed as a scientific field in the USA and Europe. It considers the benefits of nature to be utilizable and exchangeable [7–10]. After establishing the Millennium Ecosystem Assessment, there was a need to include this idea in the assessment of ecosystem services.

The Economics of Ecosystems and Biodiversity [4] is focused on the evaluation of expenses created when adopting insufficient measures to reduce biodiversity loss and the decrease in ecosystem services.

The study entitled "The Economics of Ecosystems and Biodiversity: Ecological and Economic Foundations" [4] divides ecosystem services to provisioning services, regulating services, cultural services and supporting services. The last ones are inevitable for maintaining the previous three types of services.

The development of the Common International Classification of Ecosystem Services (CICES) in 2011 was the result of the absence of standardized methodology for the classification of ecosystem services. It is connected to the framework of the System of Environmental-Economic Accounting (SEEA) of the United Nations. It is a recommended methodology of the EU Biodiversity Strategy to 2020 [11]. CICES distinguished ecosystem services as provisioning, regulating and maintenance services and cultural services.
