Target species for this project are the European-wide threatened species, which depend on bog landscapes: capercaillie (Tetrao urogallus; Annex I EU Birds Directive), moor frog (Rana arvalis; Annex IV of EU Habitats Directive), whiteface dragonflies (Leucorrhinia; Annex II and IV of EU Habitats Directive) and four-footed butterflies (Nymphalidae). Favourable conservation status of these species is important on its own but, more importantly, it is instrumental for assessing the success of different components of ecosystem restoration: (i) the hydrological network – local changes of light conditions and hydrology (R. arvalis and aquatic insects); (ii) vegetation and small-scale landscape structure (butterfly communities); (iii) the landscape structure – optimal large-scale mixture of wooded and open bog habitats (T. urogallus), all caused by habitat restoration – clear cuttings, blocking and filling in ditches.
In 2015 the existing information on the distribution and population sizes of target species will be pooled for each project site. For amphibians, aquatic invertebrates and butterflies systematic data is lacking and the assessment will be accomplished by predictive habitat modelling based on the existing survey data from other sites in Estonia. 2016 large-scale field inventories of R. arvalis, semi-aquatic invertebrates and butterflies will be implemented in all project sites, to determine their habitat use and estimate the state of populations before the bog restoration. For T. urogallus similar inventory will be carried out in Sirtsi, Tudusoo and Laukasoo project sites by Tartu Un, additional inventories (including L. lagopus and other bird species) are carried out by ELF in other project sites. The inventory of species was conducted from April to July 2016 in all project sites. Altogether 13 experts of birds, amphibians and invertebrates as well as some volunteers participated. In addition, 7 conservation camps (in total 154 participants) were held to determine the presence of Tetrao urogallus in project sites.
The restoration impact will be assessed in two stages in all project sites, linked by an adaptive (“learning by doing”) process. In 2017, there will be a contrast between intact sites and the sites where restoration has been carried out already. Habitat use by target species and its quality (e.g. water attributes, light conditions) will be estimated in restored and unrestored sites. This information will be used in modifying the restoration techniques to better address the potential conflict between priority habitats vs. priority species. After restoration, all sites are monitored in 2018 and 2019 to detect the species’ distribution in restored sites and changes in abundance. It is possible that, in the case of sensitive species and ecosystems, the loss of existing habitats (in this case: drainage ditches; overgrown bogs) can exceed the provisioning of new ones at least in the short term. Thus, monitoring of impacts of habitat restoration on target species provides information on the success of the whole project and its learning process. The latter is valuable on its own, for understanding the limits of different bog restoration measures.