Controlling broom (Cytisus scoparius) encroachment by browsing based on shrub demographic strategy

摘要

Scotch broom (Cytisus scoparius) is a very dominant species, often having undesirable environmental impacts. Browsing appears to be a powerful tool to control it, since it is targeted at the juvenile stage, which is the most sensitive in the demographic strategy of this species. A seven-year experiment on a natural Scotch broom shrubland in a French Pyrenean rangeland assessed the effects of three different browsing intensities (two levels of manual stem biomass removal simulating light and heavy browsing vs an untreated control) on juvenile survival, morphology and reproductive success at a young adult stage. These browsing strategies, representing pertinent management practices, were repeated over a five-year period. We also analysed the recoveryof broom plants, i.e. surviving young adults after two years without browsing. Our results demonstrate that browsing the young plants is a promising strategy for controlling broom.