The enemy of my enemy: concomitant impacts of goat browsing on native vegetation during invasive plant control

The goal of invasive plant management is often to benefit native plants; however, the consequences of invasive plant management on native plants are not often assessed. While this is true generally for invasive plant management, it is particularly true for targeted grazing using livestock, such as goats, which is a rapidly expanding but little‐studied method. Opinions among land managers vary widely regarding the potential effects of targeted goat browsing on native plants, ranging from anticipating strong benefits to highly destructive effects. To elucidate this issue, we experimentally tested responses of deciduous‐woodland understory plant communities to goat browsing for control of the invasive shrub common buckthorn, Rhamnus cathartica . The immediate effects of goat browsing diverged greatly from its longer‐term effects. Immediately after browsing, there were reductions in R. cathartica abundance and declines in native plant diversity and abundance. However, 1 year later, both R. cathartica and native plants had recovered. In fact, native diversity was higher in the year following browsing, perhaps due to reductions in dominance by woody species. These results provide tentative support for goat browsing as a useful component of a broader woodland restoration strategy and illustrate that conclusions drawn from studies examining only the short‐term outcomes of invasive plant management may be unreliable. Monitoring should continue for a minimum of 1 year following treatment and should address responses of both target invasive species and associated native vegetation.