Invasive Species Policy Must Embrace a Changing Climate

With increasing impacts of climate change observed across ecosystems, there is an urgent need to consider climate change in all future environmental policy. But existing policy and management might be slow to respond to this challenge, leading to missed opportunities to incorporate climate change into practice. Furthermore, invasive species threats continue to rise and interact with climate change—exacerbating negative impacts. Enabling natural resource managers and individuals to be proactive about climate-driven invasive species threats creates a win–win for conservation. Recommendations include expanding opportunities for information sharing across borders, supporting proactive screening and regulation of high-risk species on the horizon, and incentivizing individual actions that reduce ecological impacts. In addition, invasive species risk should be considered when crafting climate mitigation and adaptation policy to reduce compounding stressors on ecosystems. As we develop much-needed tools to reduce harm, policy and management must consider the combined threats of invasions and climate change.

Mapping the purple menace: spatiotemporal distribution of purple loosestrife (Lythrum salicaria) along roadsides in northern New York State

Purple loosestrife (Lythrum salicaria L.) is an invasive, herbaceous plant, frequently found in wetlands, creating monoculture stands, resulting in intensive management strategies in central New York, Ontario, and Quebec. The goal of this study was to identify the extent of infestations and to investigate factors that promote the spread of purple loosestrife. We attempted to answer several questions regarding level of infestation, connection to mowing, and influence of culverts. During flowering season in July and August, 2017–2019, we mapped infestations along 150 km (93 miles) of state highway between the Adirondack Park and the St. Lawrence River using the ESRI Collector app. The results of our preliminary analysis revealed significant increase in the number of plants (P < 0.001). In addition, a linear correlation analysis demonstrated a higher loosestrife density with an increase in plant species richness and a decrease in the distance to the closest infestation and wetland (P < 0.001 each). We found no statistical evidence that mowing promotes the spread of loosestrife. As expected, there were more individual infestations in highway ditches, but larger and denser infestations in wetlands (P = 0.003 in 2019). Culverts enable purple loosestrife to spread underneath highways and should be managed to prevent spread.