Spridningsmönster och potentiella spridningsytor hos invasionsarten stor bockrot (Pimpinella major) i Tullgarns naturvårdsområde
ett framtida problem för områdets diversitet?
An organism that is transferred from one place to another, causing major problems to the native species is termed invasive. Its natural dispersal across barriers may have been prevented but as man has turned able to rapidly travel all over the world organisms are brought to sites where they were never before observed. Adding the increasing global warming organisms may find it necessary to move around even further. This might cause major disturbance to the biological diversity, and hybridization and homogenization is one of many scenarios that could disturb the native diversity. In Sweden more that 2/3 of all alien plant species have been introduced to disturbed areas and the major introduction mechanism is gardening. The object of study in this presentation, Pimpinella major (Apiaceae) was introduced in Sweden alongside garden grasses during the 19th century but has so far spread only marginally from the areas of introduction. The aim of the study was to quantify the appearance of Pimpinella major in different types of vegetation apart from road verges, where it has been noted systematically for over a decade. The investigation area covers most of the Tullgarn nature reserve. The result shows an astonishing tendency of P. major to remain growing only along the roads in the area. The very few findings besides next to roads are from deciduous and coniferous forests and fields. It seems that Pimpinella major almost without exception prefers heavily disturbed areas and access to large amounts of nitrogen fertilizer from exhaust fumes