1 Centre for Econics and Ecosystem Management, Eberswalde University for Sustainable Development, 16225 Eberswalde, Germany. pierre.ibisch@hnee.de nuriselva@gmail.com.
2 Institute of Nature Conservation, Polish Academy of Sciences, Mickiewicza 33, 31-120 Kraków, Poland. pierre.ibisch@hnee.de nuriselva@gmail.com.