The Extent of Selected Nonnative Invasive Plants on Southern Forest Lands

—Studies suggest that the southern United States is an area of primary concern with regards to the spread of nonnative invasive plant species. Recent data show that species such as Japanese honeysuckle (Lonicera japonica) and Nepalese browntop (Microstegium vimineum) are invading forests and displacing native species throughout the southern United States. Monitoring on large spatial scales is among the most important mechanisms for detecting the spread of nonnative species. Better assessments of ongoing biological invasions are a primary research priority in the Southeast. As one method for addressing this need, a federal-state partnership initiated a survey of 33 invasive plant taxa in 2001 on all southern forest ownerships. Presence information and estimates of cover for these invasives are collected as part of the U.S. Forest Service, Southern Research Station, Forest Inventory and Analysis (FIA) program. Within the FIA program, the Southern Invasive Plant Indicator Program monitors and reports on plant invasions within southern forests; it also develops tools to detect emerging invasions and potentially threatening invasive plant populations. Results from data collected through the FIA program in the southern United States from 2001 to 2008 are described in this paper. Current distribution maps for selected nonnative invasive plants are presented, along with a discussion of the potential impacts of these species on native forests of the southern United States. 1Forester (SNO) and Research Forester (CMO), U.S. Forest Service, Southern Research Station, Forest Inventory and Analysis, 4700 Old Kingston Pike, Knoxville, TN 37919. SNO is corresponding author; to contact, call 865-862-2000, or email [email protected]