Compared to the large number of endangered species, the budget available for conservation measures is very limited. Therefore, a number of studies deals with questions of an effective use of those funds. Because an explicit consideration of all endangered species is not possible, several approaches how to choose priority species or areas are discussed in the ecological literature. On the other hand, questions on the implementation of conservation measures via environmental policy instruments are traditionally a matter of economic considerations. This thesis combines both themes by developing an ecological-economical concept, which is used for the cost-effective implementation of species conservation. As a first step, target species are determined using a species-based concept whose conservation causes umbrella effects for more species. Their conservation is implemented with different environmental policy instruments. The thesis provides an overview of relevant instruments and discusses criteria for their selection. Special attention to the particular requirements of conservation is paid by integrating so-called species- and situation-specific characteristics. The practical relevance of the theoretical considerations is demonstrated on the example of the European otter (Lutra lutra) in the Upper Lusatia.