Biology, distribution and control of the invasive species Ulex europaeus (gorse): a global synthesis of current and future management challenges and research gaps.
Ulex europaeus (Gorse) is one of the most invasive shrubs in the world, being now found in more than 50 countries where it economically and environmentally degrades the land. This highly versatile shrub can live more than 30 years and produce over 18,000 fertile seeds annually that can remain viable for over 30 years. Ulex europaeus spread is facilitated by its ability to germinate in a wide range of conditions, quick growth and maturing rate and several seed dispersal mechanisms. Despite extensive research and attempts at managing U. europaeus, current rates of control are not adequate to limit the species' competitiveness and impact on the environment. This has resulted in the species altering soil and landscape dynamics in areas of major invasion, inhibiting the growth of agricultural and native species, creating shelter for pest species and reducing the richness of competing species at a site, all of which contribute to the economic and environmental degradation of the land. This review highlights that herbicide application is the most successful technique used to control U. europaeus, although it has shown varying success across different climatic regions. In this regard, future research should investigate the possibility of integrating a range of techniques (competition, fire management, grazing, manual removal and mycoherbicides) to increase control success and reduce any potential risk of herbicide resistance. Further research is also required on the maintenance of longer-term viable populations of biological control agents to limit the success of this invasive species. Bridging the identified research gaps will help to facilitate the improved long-term management of U. europaeus and help land managers confidently to maintain sustainable land systems.