Table 1.
Features correlated with the introduction and invasion status of bamboos.
| Correlate/measurement | Expectation | Result | Consequence | Figure/table in this paper |
|---|---|---|---|---|
| Taxonomy (genera) | Introduced species will tend to come from certain genera | The genera Bambusa, Phyllostachys, Semiarundinaria, Shibataea, and Thyrsostachys had a significant proportion of species that have been introduced; and Bambusa, Phyllostachys and Pleioblastus had a significant proportion of species that were invasive (both relative to other genera) | The pool of introduced species is a very particular subset of all bamboos, so need to be careful about assessing traits linked to invasiveness only on introduced taxa | Fig. 4 |
| Phylogeny | There will be a non-random assortment of which species are introduced across the phylogeny | Only culm height showed significant phylogenetic signal, other variables including status were not | See Fig. S2 | |
| Lineage (neotropical woody, etc.) | Taxa from particular biogeographical regions are more likely to become introduced (even if phylogeny and introduction history are taken into account) | Temperate bamboos have had a high rate of species introduced compared with other lineages. Both temperate and paleotropical woody bamboos contain invasive species, but neither had a significant number compared with the other | Bamboos from other parts of the world are likely to have significant potential for utilisation in the future. Region of origin could be an important correlate of risk | Table 2 |
| Number of countries/regions a species have been introduced to | Species of bamboo that have been introduced to many ranges will have a higher likelihood of becoming invasive | The number of countries a species has been introduced to was strongly (positively) correlated with the likelihood of it being invasive | Risk and impacts caused by non-native bamboos are a function of propagule pressure | See text for details |
| Number of cultivars | Species with a greater number of cultivars will be more likely to have been introduced than species with fewer cultivars | Introduced species tended to have more cultivars | There has been a possible selection for species that show high levels of phenotypic variation, this can potentially be linked to a greater ability to adapt and so become invasive. On the other hand, more efforts may have simply been made to develop cultivars for common species | See text for details |
| Species with many cultivars will have a higher likelihood of becoming invasive | Greater number of cultivars was an important determinant of invasion | Invasiveness has been selected for during breeding and cultivation practices | ||
| Culm form | Woody lineages will have a higher proportion of introduced species than herbaceous. | Woody bamboos are preferred for introduction | As herbaceous species have had much lower rates of introduction, there has been a bias in the natural experiment. | Table 2 |
| Culm dimensions (diameter and height) | Introduced species will on average have greater culm dimensions than non-introduced species | There is an affinity for species to be introduced that have greater culm dimensions | Smaller bamboos will be less likely to have been introduced. | Fig. 5 |
| Rhizome form (running or clumping species) | Introduced bamboo species with running rhizomes are more likely to become invasive, although there is no prior expectation as to how this might affect which species are introduced | Rhizome form was not an indicator of invasive species. However, we did find more running type bamboos have been introduced (although this is correlated with temperate species which have had a bias for introduction) | Control and regulation of bamboos should consider both running and clumping forms | Table 2 |