Managing invasions by terrestrial alien plants in Ireland: challenges and opportunities.
The successful management of plant invasions is a global concern, given the large ecological and economic impacts of many introduced plant species, which may be compounded by interactions with other environmental and socio-economic changes. With the aim of identifying the challenges and opportunities associated with the management of terrestrial plant invasions in Ireland, in the light of international obligations, we review some of the most important initiatives that have been conducted to manage current invasive alien plants and the principles that should guide their management and the restoration of invaded communities. While the focus of most management practices has been based on the application of herbicide treatments and/or mechanical removal, alternative approaches may be needed in the future due to general environmental or site-related concerns. The likelihood of the widespread and successful eradication of the most significant plant invaders is, however, unlikely and more focus needs to be on a prioritised approach that targets areas where they have the greatest impact. Our ability to do this is, however, limited due to a poor understanding of the long-term impacts of plant invasions and the effectiveness of many control measures that fail to recognise species- and habitat-specific factors. An improved understanding of how the relative importance of different pathways of introduction will change in the future is also needed, including the volumes of seed traded on the internet. A range of citizen science initiatives have been promoted to raise awareness of plant invasions, with the aim of reducing the demand for ornamental species and the unintentional spread of existing invaders. These will be important for the early detection and eradication of new introductions as well as limiting the spread of existing invaders. However, the effective control of existing plant invaders requires an all-island coordinated approach supported by appropriate resources and scientific expertise.