Naturalized rainbow trout populations within other portions of native brook trout range have proven to be problematic for brook trout, principally via displacement. Generally, displacement issues are greater where naturalized rainbow trout populations are well established and more widespread. Such is the case in within some sections of Great Smoky Mountains National Park and vicinity, and in southwestern Virginia. Rainbow trout are the most dominate trout in the MountRogers area for example. North of Roanoke, the distribution of rainbow trout is more limited to spring creeks of which Pass Run is a good example. Generally, rainbow trout are more sensitive to the effects of acidification than either brook or brown trout. Pass Run, particularly the section downstream of the park, is one of the most well buffered and productive streams within or adjacent to the park since it flows extensively over limestone and is fed by a number of large limestone springs. Rainbow Trout - Shenandoah National Park (U.S. National Park Service)