Print PageBiological invasions are recognized as one of the greatest threats to the ecological and economic well-being of our planet. One of the patterns that frequently emerges for floras in different regions is that among the exotic plant species, the ones with vegetative reproduction (i.e. clonal plants) are the most invasive.
The determinants of this pattern are not known yet. In our project, we have tried to elucidate which clonal plant traits are associated with species invasiveness using a database approach.
We have constructed our database using all data from the clonal plants database (CLO-PLA). This database contains information on different aspects of clonal growth (e.g. type of clonal growth organ, yearly number of clonal offspring) of circa 3000 Central European plant species. As a proxy for global invasiveness of the species, we have added records from the Global Compendium of Weeds (Randall 2002; e.g. the number of weed lists in which the species is mentioned and the number of world regions in which the species is considered to be weedy or invasive). Furthermore, all species have been added to a phylogenetic tree to enable us to correct our analyses for phylogenetic non-independence in our data.
Results/Conclusions
Our results show that species that facultatively develop clonal growth organs are more invasive than species that develop them obligatorily. Invasive species do produce more daughter ramets per year, have a longer shoot life span, and break the connection between mother and daughter ramets sooner. Furthermore, we have found an increase in plant invasiveness with increasing distance between mother and daughter ramets, suggesting that plants with a guerilla growth form are more invasive than those with a phalanx growth form. Our results indicate that those clonal plant traits that cause a large lateral growth and spread of plants are positively correlated to invasiveness.
