Management of UK priority invasive alien plants: a systematic review protocol

Background Invasive alien plant species often have negative environmental and social impacts, such as loss of biodiversity and alteration of ecosystem services. As a result, managing the introduction, establishment, and abundance of invasive species is a major priority. To do this effectively, we need evidence on the effect of management interventions (such as using herbicide or cutting to control invasive plants). This evidence should not only include the effects of these management interventions on invasive alien species, but also on native species and other non-target outcomes such as ecosystem services. Such evidence would allow for comparison of the trade-offs between different management interventions. In the planned review we aim to assess how management interventions to control nine priority invasive alien plants species in England and Wales affect environmental outcomes. These species are: Japanese knotweed (Fallopia japonica) Nuttall's waterweed (Elodea nuttallii), Chilean rhubarb (Gunnera tinctoria), Giant hogweed (Heracleum mantegazzianum), Floating pennywort (Hydrocotyle ranunculoides), Himalayan balsam (Impatiens glandulifera), Curly waterweed (Lagarosiphon major), American skunk cabbage (Lysichiton americanus), Parrot's feather (Myriophyllum aquaticum). Methods Searches will be in English and use bibliographic databases (Scopus, Web of Science Core Collection, Open Access Theses and Dissertations, and Conservation Evidence) and internet searches (Google Scholar), as well as specialist databases. Our methodology will only use the names of each species (scientific names and common names, including synonyms) as our search string (we will not use qualifiers, such as "AND invasive"). This will give low specificity but will increase the likelihood of capturing all relevant information. We will use predefined criteria for study inclusion and data extraction. We will screen publications in two stages: (1) using titles and abstracts and (2) using full texts. Consistency of inclusion will be checked by two people screening a random sample of 10% of titles and abstracts. This dual-screening will be subject to kappa analysis and any disagreements resolved through discussion. We will use critical appraisal to assess study validity by identifying studies that are potentially prone to bias.