Pimpinella Saxifraga Is Maintained in Road

17 Road verges have been proposed as refuges for vulnerable grassland species in the 18 modern, changing landscape, but little comparative knowledge exists on how 19 management regimes affect population dynamics of such species. We compared the 20 effects of various management regimes on population dynamics of Pimpinella saxifraga 21 in road verges and pastures, using elasticities and LTRE-analyses with underlying vital 22 rates as model components in three road verges and three pastures in a agricultural 23 landscape in western Norway. Under present management regimes, we observed 24 slightly higher projected population growth rates in pastures than in road verges. The 25 pasture populations had comparatively lower survival but higher reproduction than the 26 road verge populations, thus demonstrating a management-induced negative correlation. 27 Such negative correlations generally increase species’ adaptability to environment 28 changes, thereby reducing the extinction risk. We generally observed small changes in 29 P. saxifraga demography to management but considerable variation along 30 environmental gradients, underlining the importance of studying multiple populations. 31 The linear form of the road verges enabled a fine-scale mosaic application of different 32 management regimes. Individuals growing in zones receiving survival-lowering 33 management produced seeds that compensated the lack of seeds in zones receiving 34 fertility-lowering management. The study indicates that road verges may represent 35 refuges for vulnerable grassland species like P. saxifraga, given proper management. 36 The observation of ‘mosaic’ management that allows road verge metapopulations to 37 complement each others life-history characteristics exemplifies the unique potential of 38 road verge ecosystems to maintain semi-natural grassland species, as well as providing 39 habitats for different species exhibiting various life histories. 40 Key-words: LTRE, mosaic management, population growth rate, resource allocation 41 trade-offs, semi-natural grassland, source-sink populations, vital rates 42