Approaches in demographic modeling for predicting population persistence across a moisture gradient of an invasive, hybridizing weed (Raphanus SPP.)

Human-induced global climate change has altered precipitation patterns, with consequences for weed infestations. Cultivated plants are known to readily hybridize with their wild relatives, which may create more problematic weeds in future environments. I compared the demography and seed bank dynamics of wild radish and crop-wild hybrid radish populations across a soil moisture gradient. In a seed-burial experiment and weekly population censuses, I assessed frequency and timing of various demographic parameters. Germination rates declined with time in the low rain treatment, but increased in the double rain treatment. Wild seedlings tended to emerge later than hybrid seedlings. Hybrid populations had marginally higher population growth rates (λ) than wild populations. Fecundity had the greatest influence on λ. This study better informs weed control measures by predicting seed banks’ role in population persistence and by isolating the most effective life-history stage ‘choke point’ to suppress population growth given new climate change scenarios.