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Oecologia
DOI 10.1007/s00442-013-2869-3
POPULATION ECOLOGY - ORIGINAL RESEARCH
Linking vital rates to invasiveness of a perennial herb
Satu Ramula
Received: 9 March 2013 / Accepted: 18 December 2013
© Springer-Verlag Berlin Heidelberg 2014
between regions. The population growth rate increased
linearly with plant establishment, and with the survival
and growth of vegetative individuals, while the survival of
flowering individuals and annual seed production were not
related to λ. The vital rates responsible for rapid population
growth varied among populations. These findings highlight
the importance of both regional and local conditions to
plant population dynamics, demonstrating that individual
vital rates do not necessarily correlate with λ. Therefore,
to understand the role of individual vital rates in a species
ability to invade, it is necessary to quantify their effect on
population growth rate.
Keywords Demography · Fitness · Invasion ecology ·
Population dynamics · Population growth rate
Introduction
Invasiveness is usually characterized as successful popula-
tion establishment and rapid spread across heterogeneous
landscapes. Species traits are of great interest in invasion
ecology because they could potentially be used to predict
species invasiveness outside their native range (Rejmánek
and Richardson 1996). In particular, traits directly related
to the fitness of individuals, such as survival, growth and
fecundity (i.e. vital rates), are often used to provide infor-
mation about invasiveness (reviewed by Daehler 2003;
Pyšek and Richardson 2007). Comparative reviews of
vascular plants have shown that invasive plant species are
larger in size and have a greater reproductive output and
better survival than non-invasive ones (Mason et al. 2008;
van Kleunen et al. 2010). However, others have found that
this is not always the case (e.g., Schumacher et al. 2009;
Flores-Moreno and Moles 2013). Further, plant vital rates
Abstract Invaders generally show better individual per-
formance than non-invaders and, therefore, vital rates
(survival, growth, fecundity) could potentially be used to
predict species invasiveness outside their native range.
Comparative studies have usually correlated vital rates
with the invasiveness status of species, while few studies
have investigated them in relation to population growth
rate. Here, I examined the influence of five vital rates (plant
establishment, survival, growth, flowering probability,
seed production) and their variability (across geographic
regions, habitat types, population sizes and population den-
sities) on population growth rate (λ) using data from 37
populations of an invasive, iteroparous herb (Lupinus poly-
phyllus) in a part of its invaded range in Finland. Variation
in vital rates was often related to habitat type and popula-
tion density. The performance of the populations varied
from declining to rapidly increasing independently of habi-
tat type, population size or population density, but differed
Communicated by Miguel Franco.
Electronic supplementary material The online version of this
article (doi:10.1007/s00442-013-2869-3) contains supplementary
material, which is available to authorized users.
S. Ramula (*)
Aronia Coastal Zone Research Team, Åbo Akademi University
and Novia University of Applied Sciences, Raseborgsvägen 9,
10600 Ekenäs, Finland
e-mail: sramula@abo.fi
S. Ramula
Department of Biology, Biodiversity Unit, Lund University,
223 62 Lund, Sweden
S. Ramula
Section of Ecology, Department of Biology, University of Turku,
20014 Turku, Finland