Revista Chilena de Historia Natural 77 (3): 411-437, 2004
RESEARCH ARTICLE
Disruption of ecosystem processes in western North America by invasive
species
Many ecosystems of western North America have been dramatically changed by non-
native species. Here, we review ecological impacts of 56 plant, animal, fungus, and protest species that were brought to this region by
humans. We discuss characteristics of invasive species that can lead to major ecosystem impacts, and explore how invasive species
alter many different attributes of ecosystems. Specifically, we include examples of invasive species that affect geomorphology, fire
regimes, hydrology, microclimate, atmospheric composition, nutrient cycling, and productivity. Finally, we review the direct
consequences of biological invasions for some native species. We summarize examples from this paper in Appendix 1. Our examples
illustrate how, as invasive species have become dominant across large areas of western North America’s grassland, shrubland, dune,
riparian, and estuarine ecosystems, the properties and functioning of these systems have changed. To date, some systems in this
region, such as its forests, remain relatively unaffected by invasive species. However, recent attacks of forest pathogens highlight the
potential vulnerability of these ecosystems.
Key words:
biological invasions,
ecosystem functioning, community structure, exotic species, impact
