Volume 33, Issue 3, 1 June 2015, Pages 300-317
a
Biological Museums, Dept of Biology, Lund Univ., PO Box 117, Lund, Sweden
b Swedish Museum of Natural History, PO Box 50007, Stockholm, Sweden
c IFM Biology, Conservation Ecology Group, Linköping Univ., Linköping, Sweden
b Swedish Museum of Natural History, PO Box 50007, Stockholm, Sweden
c IFM Biology, Conservation Ecology Group, Linköping Univ., Linköping, Sweden
Abstract
In a north European
context, identifying invasive species is far from trivial because the
vegetation has been influenced by human activities for thousands of
years. New species have immigrated continuously since the end of the
last glaciation, both spontaneously and through direct or indirect help
by man. Still, newly immigrated species may be problematic in a nature
conservation context and may harm biodiversity, and cause changes in
ecosystem services. In this study, all 721 presently established
vascular plant and bryophyte taxa known to have been introduced to, or
to have immigrated to, Sweden since the year 1700 are assessed for their
invasive potential. The assessment is based on six components
considered relevant for their invasiveness: 1) ability to compete in
natural vegetation, 2) ability to form dense populations, 3) realized
dispersal ability, 4) gene flow to native relatives, 5) time since
immigration and 6) distance to their native range. Although the relative
importance of these components is context dependent, a compound general
index of invasive concern is proposed and calculated for all taxa. The
index of invasive concern is validated by comparing it to assessments by
a Bayesian Belief Network in which the influences of the same six
components are assigned by expert opinions. In addition, rough estimates
of the present-day abundance of each taxon in Sweden are presented. The
origin, biology and possible impact of the 150 taxa with the highest
index values are discussed. Based on the index of invasive concern,
Campylopus introflexus, Epilobium adenocaulon, E. ciliatum, Rosa rugosa,
Lamiastrum galeobdolon subsp. argentatum, Orthodontium lineare,
Solidago canadensis, Calystegia sepium subsp. spectabilis, Rubus
armeniacus and Prunus serotina are identified as the ten most problematic alien vascular plant and bryophyte taxa in Sweden. © 2015 Nordic Society Oikos.
Indexed keywords
GEOBASE Subject Index: biodiversity; bryophyte;
ecosystem service; evolutionary biology; flora; gene flow; human
activity; immigration; invasive species; invasiveness; last glaciation;
nature conservation; new species
Regional Index: Sweden
Species Index: bryophytes; Calystegia sepium;
Campylopus introflexus; Epilobium ciliatum ciliatum; Lamiastrum
galeobdolon; Orthodontium lineare; Prunus serotina; Rosa rugosa; Rubus armeniacus; Solidago canadensis; Tracheophyta
