Examples of the most common surrogate types in conservation literature. Biodiversity surrogate types are in the middle of the image (the green area separated by a dashed line) and surrogate types discussed in this study are delimited within the blue line. Some of the flagship species also have significance as biodiversity surrogates and therefore belong to the green area, while others are being used ambiguously or purely for marketing purposes. Indicator species that are used to monitor the quality of the environment or changes in it are not included in biodiversity surrogates (the brown area) and our study.