175Hamilton et al. ( 2005 ) suggested that introduced plants with low seed mass are likely
to be successful invaders in areas disturbed by humans. However, Moles and Westoby
( 2006 ) found that larger and heavier seeds may be more likely to survive in soil and
that species with high seed mass have a higher seedling survival rate. Schmidt et al.
( 2012 ) studied North American native plants and found that species having seeds with
Fig. 6.4 Frequency distribution of species’ mean seed masses by taxonomic section in the Bromus
genus, for introduction or impact categories combined ( left panels ) or separated ( right panels ).
Species may be both widely introduced and weedy and may be included in multiple weed
categories
6 Attributes That Confer Invasiveness and Impacts Across the Large Genus Bromus...