Biodivers Conserv https://doi.org/10.1007/s10531-018-1521-2 1 3 ORIGINAL PAPER The efects of forest succession and grazing intensity on bird diversity and the conservation value of a Northern Adriatic karstic landscape Primož Kmecl 1  · Katarina Denac 1 Received: 2 March 2017 / Revised: 15 February 2018 / Accepted: 22 February 2018 © Springer Science+Business Media B.V., part of Springer Nature 2018 Abstract We studied the efects of diferent land uses on conservation value and bird diversity in a Northern Adriatic karstic landscape. Our research area was situated in SW Slovenia and was covered with dry pastures and meadows in diferent stages of forest suc- ession and with diferent grazing intensities. We surveyed birds in 2007 and 2012 using the line transect method, with 50.4 km being covered each year. In the analysis we divided the survey transects into 200 m tiles which were used as statistical units in the analysis. We then modelled conservation value, bird diversity and bird abundances with diferent land uses; we used boosted regression trees as a modelling tool. Canonical correspond- ence analysis showed that a distinct group of birds occurred on tiles with higher grazing intensity. The species in this group also had signifcantly higher abundances in 2012 than in 2007. Forest succession was the most important predictor of SPA conservation value (Special Protected Areas according to the Directive on the conservation of wild birds of the European Union) and had negative efect on it; grazing intensity had a unimodal posi- tive infuence on conservation value and was most benefcial at low intensity. The model for the European conservation value showed a rather low predictive power. Farmland bird diversity was also negatively afected by forest and positively by grazing intensity. For the four Natura 2000 species—protected species in the SPA Kras (Woodlark Lullula arborea, Red-backed Shrike Lanius collurio, Corn Bunting Emberiza calandra and Skylark Alauda arvensis), forest cover also had a negative efect. Grazing intensity had a positive efect for Woodlark, Red-backed Shrike and Skylark. The highest SPA conservation value and farmland bird diversity could therefore be achieved in a landscape with as low a forest suc- cession as possible and grazing present but at low intensity. We recommend inclusion of Communicated by David Hawksworth. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s1053 1-018-1521-2) contains supplementary material, which is available to authorized users. * Primož Kmecl primoz.kmecl@dopps.si 1 DOPPS – BirdLife Slovenia, Tržaška cesta 2, SI–1000 Ljubljana, Slovenia