To mitigate and prevent biodiversity loss due to invasive species, ecologists and wildlife managers must actively monitor and stop the spread of exotic species from entering native ecosystems. When prevention fails, control programs may be used to remove the exotic species by the most effective method, including mechanical, chemical, or biological means. However, examples of successful control are rare. This study assessed efforts by the New York State Department of Conservation (NYSDEC) to control giant hogweed in New York State. Giant hogweed is a federally listed noxious weed that can impact native plant species and also human health. NYSDEC Division of Lands and Forests Bureau of Invasive Species and Ecosystem Health has targeted giant hogweed by targeting all locales where it is known to grow with mechanical and/or chemical treatment. Sites are treated each year until plants are gone, and then monitored for 9 years before a site is declared “controlled”. We modeled how the initial size of the infestation and the duration of treatment affected the likelihood of success in controlling individual giant hogweed infestations. The number of sites increased from 2008 to 2022 to a total of 4112 during the timeline of our data, but the state-wide total area of infestation and average area per site decreased. We found that the probability of successful control of individual infested sites - defined by 9 years without plants - was 30% for the smallest sites and decreased as a site’s infestation size increased. Although the probability of complete control at each site was relatively low, current methods implemented by the NYSDEC successfully decreased the size of individual infestations. We emphasize that identifying sites in the early stages of infestation - when the area needing control is small - provides the NYSDEC with the greatest possibility for success.
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