Regulation of Jacobaea vulgaris by varied cutting and restoration measures

Abstract

The growth of the noxious grassland weed Jacobaea vulgaris Gaertn. in pastures is a threat to grazing animals. This is especially true when it dominates vegetation cover, which often occurs on non-intensively used pastures that are managed with the nature-conservation goal to maintain and promote biodiversity. Thus, we wanted to find management techniques to reduce J. vulgaris without harming the floral biodiversity on the pastures. We tested six different mechanical and cultural methods to reduce the presence and spread of J. vulgaris. Seven study sites in Northern Germany (Schleswig-Holstein) were treated with various measurements, including: milling and seeding, hay transfer, mowing regimes at different times and frequencies, and combinations of mowing and seeding. Our results show that cutting within the bloom of the plant at the end of June and again four weeks later, when the plant is in its second bloom was the most effective treatment in reducing J. vulgaris abundance. This was the only treatment leading to a significant reduction in population growth rate and density without reducing surrounding plant species richness. The study reveals that management of J. vulgaris in non-intensively used pastures is possible, while preserving species-rich grasslands.