Residence time determines the distribution of alien plants - Invasive Plants: Ecological and Agricultural Aspects - page 66

Figure 2. Examples of relationships between frequency and distribution range of alien species and
minimum residence time (MRT, in yrs). See Table 1 for parameters of standardized relationships.
Empty circles and dashed line refers to casual, solid squares and solid line to naturalized species on
figures referring to all aliens.
rare species that do not persist in the wild without repeated input of diaspores
by human activities [42]. Obviously, the longer the casuals are present the more
islands they colonize but the propagule pressure might have been too low to
ensure simultaneous increase in frequency; regardless of how long they have
been present, their frequency is on average the same. This suggests that for
casuals “being at the right place at the right time”, i.e., earlier than others, man-
ifests primarily into a better chance to achieve a wide range but not to become
more frequent.
The pattern is different in the Czech Republic, where only frequency is
available as a measure. Naturalized species again invaded significantly earlier