Cryptic invasions are a largely unrecognized type of biological invasion
that lead to underestimation of the total numbers
and impacts of invaders because of the
difficulty in detecting them. The distribution and abundance of Phragmites australis in North America has increased dramatically over the past 150 years. This research tests the hypothesis that a non-native
strain of Phragmites is responsible for the observed spread. Two noncoding chloroplast DNA regions were sequenced for samples collected worldwide,
throughout the range of Phragmites.
Modern North American populations were compared with historical ones
from herbarium collections. Results indicate that an
introduction has occurred, and the
introduced type has displaced native types as well as expanded to
regions previously not
known to have Phragmites. Native types apparently have disappeared from New England and, while still present, may be threatened in other parts of
North America.
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