Due to both economic reasons and potential significant impacts to the City’s Natural Heritage System, social impacts, or human health and safety concerns, efforts must be focused on “priority species”. Effective invasive species control can only come from focused and sustained efforts over the long term. Without this, reintroduction into managed areas is likely and the original time, resources, and funds put into the project could be wasted. The City of London will focus on the following species and designate them as “priority species”: While all ‘watch-list’ species can have negative impacts, these species have been identified as “priority” due to either the ongoing significant impacts to the NHS, potential significant impacts to the NHS, and/or public health and safety.
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Phragmites
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Japanese Knotweed
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Dog Strangling Vine
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Common & Glossy Buckthorn
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Giant Hogweed
Developing a watch list to highlight particular species of concern in the London area will increase the likelihood of new invaders being caught quickly. Identifying and recording all vectors (or pathways of introduction) is crucial to managing the introduction of future invasive plant species. Vectors (pathways of introduction) can include the following:
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River, stream and ravine corridors
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Drainage ditches (along roadways)
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Garden escapes/disposal of yard waste in natural areas (and other encroachments)
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Nursery sales
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Contaminated topsoil/mulch
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Contaminated equipment
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Long lasting seedbank on heavily invaded sites