Does a voluntary conservation program result in a representative protected area network?: The case of Finnish privately owned forests

Conservation contracting has attained growing interest worldwide as a tool for protecting biodiversity in privately owned lands. In this policy, landowners receive payments from an environmental agency in exchange for land use practices that contribute to the supply of biodiversity. This approach may result in a conservation network which does not cover all focal ecological characteristics, because landowners determine the supply of potential targets. In addition, the contracts are typically allocated by using a scoring method that is not giving information on the representativeness of the species composition of the sites. In this study, we investigated what is the performance of a voluntary conservation program in selecting sites that would maximize the number of specific target species in the selected conservation network subject to a given budget constraint. We focused on the Finnish pilot program named Trading in Natural Values (TNV). Our data consisted of 56 mature stands covering both stands that were offered to the TNV program and stands that were not offered. All the stands were surveyed for specific groups of wood-inhabiting fungi and epiphytic lichens that can be considered as good surrogates for forest species diversity. Our results showed that the participation in the TNV program was large enough to meet the ecological goals, because the offered targets uncovered only two of the 73 surveyed species, and the cost-effective conservation network included only a few targets that were not offered in the pilot program. However, the contract allocation method used in the TNV could be improved, because many ecologically valuable targets that were offered to the program were not accepted. In general, it could be justified to survey some indicator species, which would be relatively easy to identify, to maximize species coverage in contract allocation. Surveying indicator species causes some extra costs, but these are likely to be minor compared with the costs savings in opportunity costs, due to the improved targeting of protected areas.