Disturbance is commonly thought to promote biological invasion. However, disturbance can also be used as a management tool to control invasive species. In particular, it may be possible to manipulate up to five aspects of disturbance: frequency, intensity, duration, extent, and timing, as appropriate. We use a two cohort experiment to examine how one type of disturbance, mowing, can be used as a management tool to affect the growth, survivorship, reproduction and phenology of two invasive thistles Carduus nutans and C. acanthoides.
Results/Conclusions
Our results show that increasing intensity and including a late mow in the mowing strategy efficiently reduced the height and flowerhead number of the two species at the end of the growing season. However, high frequency mowing at a low intensity level did not affect ultimate flowerhead production because more stems were induced. Mowing also delayed the flowering of the two species and elongated their growing seasons. Our results provide important insights for application of mowing disturbances to control these two invasive species in particular. Our work also demonstrates how important it is to assess multiple aspects of a disturbance when seeking optimal control strategies for invasive species in general.
