Residence time determines the distribution of alien plants - Invasive Plants: Ecological and Agricultural Aspects - page 58

Residence time determines the distribution of alien
plants
Petr Pyˇek 1,2 and Vojtˇch Jaroˇík 2,1
1 Institute of Botany, Academy of Sciences of the Czech Republic, CZ-25243 Pr ° honice, Czech
Republic
2 Department of Ecology, Faculty of Sciences, Charles University, Viniˇná 7, CZ-12801 Praha 2,
Czech Republic
Introduction
Determining which biological traits enable a species to become invasive has
been a major objective in invasion ecology [1-5]. Part of the theory relies on
comparisons of large species sets; such studies attempt to identify the factors
that contribute to the probability that a species will be introduced to a region [6]
and become naturalized or invasive [7-9]. It has been shown that different fac-
tors are of different importance at particular stages of the invasion process [6,
10]. Recently, sophisticated data on alien floras from around the world have
become available in the scientific literature [8, 11-16]. Some biological and
ecological traits of invading species were identified as contributing to the suc-
cess of invasive species, e.g., high fecundity [17], efficient dispersal [18], abil-
ity to utilize generalist mutualists [19], ability to evade specific natural enemies
[20], small genome size [3], relative growth rate [5] or specific leaf area [5, 20].
However, not only species' biological traits are important. Cultural influ-
ence has been recognized as an important factor co-determining the fate of
species subsequent to their first introduction to a new area [21, 22]. Recently,
it has been emphasized that stochastic effects, which depend on initial inocu-
lum size, residence time, and the number of introduction events (propagule
pressure) and their spatial distribution [23] co-determine whether a species
becomes invasive. One of the robust emerging generalizations of invasion biol-
ogy is that the probability of invasion success increases with residence time
[24], i.e., the time since the introduction of a taxon to a new area. Residence
time represents another dimension of propagule pressure: the longer the spe-
cies is present in the region, the more propagules are spread and the probabil-
ity of founding new populations increases [25]. As it is usually not known
exactly when a taxon was introduced, the term 'minimum residence time'
(MRT) has been suggested and used in the literature [24-27].
Herein, we utilize available data to determine the effect of residence time in
plant invasions in detail at two temporal scales. First, the phenomenon is ana-