Conservation of Northern European plant diversity: the correspondence with soil pH

Effective biodiversity conservation requires an analysis of the existing reserve system. In temperate and boreal regions, plant diversity has a strong positive association with soil pH. Consequently, in order to protect plant diversity effectively, a relatively large proportion of protected areas should be on high pH soils. Since biodiversity data are never complete for all taxa, biodiversity indicators, e.g., threatened species, should be used. We studied soil pH distributions in protected areas in Northern Europe and tested whether soil pH requirement differs between threatened and non-threatened bryophyte and vascular plant species. As result, the proportion of high pH soils in protected areas was significantly greater than the proportion of these soils in general. This ensures that a large regional pool of plant species preferring high pH soils is relatively well protected. Threatened and non-threatened species in Northern Europe did not differ in their soil pH requirements, but threatened species required a narrower soil pH range than non-threatened species. Consequently, threatened species diversity can be used for indicating overall plant diversity.     

Grouping and prioritization of vascular plant species for conservation: combining natural rarity and management need

National and International Red Lists and Legal Acts specify species with conservation needs, mainly on the basis of personal experiences. For effective conservation we need scientifically justified prioritization and grouping of these species. We propose a new combined approach where species are grouped according to the similar activities needed for their conservation. We used the national list of vascular plant species with conservation need for Estonia (301 species), and linked these species to eight qualitative conservation characteristics, four reflecting natural causes of rarity (restricted global distribution; restricted local distribution within a country; always small populations; very rare habitat type), and four connected with nature management (species needing the management of semi-natural grasslands; species needing local disturbances like forest fires; species needing traditional extensive agriculture; species which may be threatened by collecting). Only one positive association occurred among the characteristics - between restricted local distribution and small size of populations. Thus, natural causes of rarity and management aspects are not overlapping, and both should be used in conservation activities. Species grouping by different conservation characteristics allows one to focus on species groups with similar conservation needs instead of individual species. Prioritization of species with conservation needs can be based on the number of conservation characteristics that are associated with a particular species. Our prioritization did not correlate with the categories of the national Red Data Book, but a positive association was found with legal protection categories. The legislation, however, covers only the natural causes of rarity. We propose a new combined approach for plant species’ conservation planning that starts by considering human induced rarity and progresses through to natural rarity causes.     

Establishment of protected areas in different ecoregions, ecosystems, and diversity hotspots under successive political systems

Protected areas are valuable tools for nature conservation but the effectiveness of reserve networks must be monitored continuously. Knowing the history of the establishment of protected areas can help to improve future conservation. We explore how different ecoregions, ecosystems and diversity hotspots have been incorporated in protected areas in Estonia during the last century. We found that the average rate of establishment of protected areas has been surprisingly constant despite profound changes in political systems. However, establishment of protected areas has varied regionally; an agricultural region in south-east Estonia has seen less protection, partly due to lower biodiversity. Wetland ecosystems were initially more placed under protection, whereas recently semi-natural grasslands have gained more attention. In contrast, farmland is under-protected. Surprisingly, biodiversity hotspots were no more protected than the national average. We consider how the development of a protected area network has been influenced by individual persons and public opinion under successive political systems. We suggest that simultaneous gap analysis of ecoregions, ecosystems and diversity hotspots provides a more complete picture than examining a single aspect. Therefore this study can be used as a model for other regions.