Cryptic Invasion

A cryptic invasion is one in which it is hard to distinguish the difference between the native species and the non-native species [1]. This poses a problem for scientists trying to remove or prevent the establishment of invasive species because it makes it difficult for them to tell the difference between the normal native species and the destructive non-native species. Cryptic invaders frequently outcompete their nearly identical native counterpart, so it is important for scientists to be able to identify them and attempt to remove them before they cause too much damage [1]. Their close appearance also makes it possible for them to invade without scientists noticing right away, further influencing their establishment [1].

A common example of a cryptic invader is the plant species ''Phragmites australis. ''This species is found in numerous areas across North America, but it has greatly increased in abundance in the past 150 years [2]. Scientists have determined that a non-native strain of Phragmites is the cause of this increase in abundance. They have also determined that the non-native strain has displaced much of the native strain, as well as expanded its range to areas that Phragmites wasn't previously found [2].

References:

1.Carbo, A. 2007. Common Reed ( Phragmites australis ). University of Montana. Retrieved from: http://fwcb.cfans.umn.edu/courses/nresexotics3002/GradPages/Phragmites/cryptic.html

2. Saltonstall, K. 2002. Cryptic invasion by a non-native genotype of the common reed, Phragmites australis, into North America. Proc Natl Acad Sci USA 99: pp. 2445-9. Retrieved from: http://www.pnas.org/content/99/4/2445.full