2.3. Data extraction
Suitable articles were reviewed manually and independently by two researchers. Files were exported in .csv (CSV) format for initial analysis, containing the following information: authors, title, year of publication, source, and document type for those analysed by Scopus, and authors, title, and source for articles analysed by WOS. Data extraction was done using an Excel® spreadsheet and collecting the following information from the full-text articles: ID, database in which the article is present, title, author(s), year of publication, ecosystem service category (provisioning, regulating, supporting, and cultural services) using the Millennium Ecosystem Assessment classification system
(Millennium Ecosystem Assessment 2005) Land Use, Land-Use Change and Forestry (LULUCF) activities, MBIs, spatial scale, geographical area, current market status (already implemented or only potential), presence or absence of an estimated Willingness to Pay (WTP), Willingness to Accept (WTA) compensation in the analysed paper, type of stakeholder involved, decision-making process adopted, and additional notes (
Table 2,
Appendix A).
To simplify the data extraction process, some variables were classified according to classification criteria already available in the literature.
Regarding the spatial scale, reference was made to the classification proposed by
Krishan and Singh (2019). At the “local” level, studies with reference to forest stands, municipalities, districts, and provinces are included. At the “subnational” level, studies on the geographical basis of counties, regions, and federated states are included. At the “national” level, countries are included, while at the “international” level, studies that include more than one country are included.
About the category of stakeholders, the classification proposed by
Nisbert et al. (2020) and
Paletto et al. (2021) was used. “Sellers” are those who manage natural capital and are responsible for its conservation, protection, and improvement through good management practices. “Buyers” are those who purchase the service provided by natural capital and provide seed capital to start implementing the PES scheme. “Intermediaries” are those who manage the market, regulate it at different scales or facilitate its development, and protection. Finally, “knowledge providers” are those involved in providing technical and scientific advice, promoting the market, and evaluating and monitoring its effectiveness.
MBIs have been grouped into five main options based on the intrinsic properties of the instrument.
Contracts include the following options: Payments for Environmental Services (
Wunder 2005)—also known as PES—watershed management contracts, reforestation contracts, and biodiversity management contracts.
Financial instruments include the following options: shares, bonds, CALL and PUT options (i.e., the rights to buy in the first case and to sell in the second to the holder who holds them, a given stock), crowdfunding.
Incentives include subsidies, government payments, green payments, private payments, and property tax incentives.
Tradable certificates include offset/carbon credits, certified emission reductions, and transferable development rights. There are no options in the
Auctions.