Large-Scale Assessment of Invasiveness and Potential for Ecological Impact by Nonnative Tree Species.This article is part of a larger document. View the larger document here.
Biological invasions represent one of the most significant environmental threats to the maintenance of natural forest ecosystems in North America and elsewhere (Liebhold and others 1995), and have been estimated to cause more than $100 billion annually in damage and control costs (Pimentel and others 2000). However, these costs do not take into account the economic value of nonmarket ecosystem services such as landscape aesthetics, outdoor recreation, and the knowledge that healthy forest ecosystems exist (Holmes and others 2009). Failure to address biotic invasions could result in severe consequences, including wholesale loss of natural resources in some regions, disruption of the natural processes that supply ecological services important to humans, and the impoverishment of ecosystems with the spread of cosmopolitan species (Mack and others 2000).