Sarah Reichard
Wednesday, October 15, 2008 - 8:30-9:00
Weed risk assessments usually include a number of biological factors used to determine potential invasiveness. Biological traits include those related to fast growth, high rates of reproduction, effective dispersal, dormancy, and difficulty of control. Climate change is expected to bring increasing temperatures and levels of CO2 and nitrogen. These changes may alter some of the biological traits associated with invasiveness, requiring a change of weighting in assessments for them to maintain accuracy. For instance, rising CO2 may change root to shoot ratios, making some species more difficult to control. Nitrogen-fixing plants may become even more invasive. Increasing temperatures have been shown to encourage shrub growth and will likely shift potential ranges, affecting range modeling. C4 species, including many invasive grasses, have shown decreased seed production and recruitment in response to increasing CO2 and temperature. None of these expected responses will invalidate any of the risk assessments currently used or under development, but may affect their accuracy. Awareness of changing plant responses to the environment under climate change may help maintain accuracy.
Keywords: WEED RISK ASSESSMENT, CLIMATE CHANGE